decorative ceramic tile, probably, will not soon lose its relevance - and this despite the huge number of various finishing materials on the shelves of hardware stores. And since there is a non-decreasing demand for products (and this, as you know, is almost half the success), then why not create an appropriate offer? And it would be wrong to assume that any manufacturing enterprise in the construction segment will require large investments. For example, a mini-plant for the production of ceramic tiles in Russia can pay off in less than a year. What details have to be thought out by a person who has paid attention to this market niche.

Our business valuation:

Starting investments - from 2500000 rubles.

Market saturation is low.

The complexity of starting a business is 6/10.

Why is the production of ceramic tiles profitable?

Of course, in the case of large-scale production, a small workshop will bring much less profit. But the advantages here are also more than enough, the main of which is the affordable price of equipment. In addition, in this case, it is necessary to work with individuals, and it is much easier to find such customers than wholesalers.

A mini-workshop for the production of ceramic tiles can produce high-quality products at a cost that is quite acceptable to consumers. Judge for yourself - many of the major players in the market are only dealers of major European brands, and the increase in exchange rates has made the products they sell quite expensive. "Small" producers will not adhere to such high prices for finished products - raw materials are inexpensive.

Main competitive advantage, with the help of which a novice entrepreneur will be able to draw the attention of buyers to their products - the design of ceramic tiles. Large enterprises can hardly boast of a variety of product lines - quantity is more important here. But a small workshop can create truly unique products.

The main difficulties that the "young" enterprise will face are the development of recipes and original collections.

Product range

In order for production, albeit small, to bring maximum profit, it is necessary to expand the range as much as possible. Then each client will be able to choose what he needs.

All subsequent actions will depend on what type of product is planned to be launched - the selection of a recipe, the purchase of raw materials and equipment.

All ceramic tiles can be divided into several large groups.

And the products differ not only in the method of production, but also in their purpose:

• porcelain stoneware (high-strength product obtained by sintering a mixture of 2 clays, quartz, spar and pigments),
• double-fired tiles (a product that is fired twice during the manufacturing process),
• single-fired tile (a product that is fired 1 time during the manufacturing process),
• clinker (single-fired glazed or unglazed product with a compacted base, cured by extrusion),
• cotto (porous single-fired product made of red clay, obtained by extrusion).

According to the “fields of application”, tiles can be distinguished: for floors, for walls, mosaics, for interior cladding, for outdoor work. Practice shows that the manufacture of ceramic tiles for walls and floors brings great profit to an entrepreneur, since this is the most popular product among consumers.

When working on the assortment, it is important to correctly calculate your capabilities - some types of products will require additional expensive equipment.

The main stages of ceramic tile manufacturing technology

Technological scheme for the manufacture of ceramic tiles

It may seem that the technology for the production of ceramic tiles is difficult to implement, because this is a process within an industrial enterprise. In fact, this is not so - even a person who is far from the manufacturing industry can figure it out.

In general, there are several methods for making tiles. But the easiest to implement is the pressing method. It does not require bulky devices, renting large areas, hiring highly qualified specialists, and therefore this is the best option for a mini-workshop.

And no matter what products are manufactured, the technological scheme of the pressing method looks like this:

• dosing components,
• mixing of raw materials
• raw material pressing,
• drying,
• burning.

To develop a client base, manufacturing finished products should be debugged - no marriage!

What raw materials will be required?

The necessary raw materials for the production of ceramic tiles can be obtained in any region. You should not rush to choose a supplier, since each of them offers different conditions for cooperation. Therefore, it would be better to pre-monitor this market.

The list of main components includes the following components:

• Clay and kaolin.
• Sand.
• Spars, slags, nephelines.
• Various additives (surfactants, thinners).

Even if you plan to make ceramic tiles with your own hands, it is important to supply only high-quality raw materials. Cheap components of a poor composition will negatively affect the quality of the finished product.

Mini workshop equipment

Line for the production of ceramic tiles

To start production, you need to buy equipment for the production of ceramic tiles. Offers on the market industrial equipment mass - starting manual machines and ending with high-performance lines.

To organize a mini-workshop, you will need low-power devices, and, accordingly, their cost will be quite accessible only to an entrepreneur who is getting on his feet. The basic equipment of the line consists of the following machines:

• Concrete mixer. Price - from 30,000 rubles.
• Vibropress (forms - separately). Price - from 70,000 rubles.
• Kiln for drying and roasting. Price - from 1500000 rubles.

If according to the recipe it is planned to glaze finished products, then a special chamber will also be required, the cost of which is 80,000-100,000 rubles. The line can also be supplemented with an extruder (≈150,000 RUB) and a tile cutting machine (≈80,000 RUB) to introduce other production methods.

The final price of the equipment will depend on the degree of automation and capacity. And if for the production of products at home it is possible to equip a workshop for 2,000,000 rubles, then the cost of industrial lines sometimes exceeds 1,000,000 rubles.

Sales market and business payback

Sale of ceramic tiles can be carried out both wholesale and retail lots. Look for clients among:

• construction shops and markets,
• construction and renovation companies,
• individuals.

It has been proven in practice that the mini-production of floor ceramic tiles can fully pay for itself already a year after the launch. And the costs here can reach 2500000 rubles. (purchase of a line, rent of premises, purchase of raw materials). But such quick payback- this is an ideal case when the distribution channels are debugged from the first for the operation of the line. Most start-up entrepreneurs in the first year of operation of the workshop face the problem of seasonality, when winter-autumn period line is idle. And to prevent this from happening, we throw all our efforts into advertising our products.

Mixtures of various materials are used:

1. clay materials that provide the plasticity of the wet mass necessary for molding tile blanks;
2. quartz raw material - mainly quartz sand, which forms the "skeleton" of a ceramic product, that is, it performs the structural function necessary in order to limit and control the dimensional change of the product, which is inevitable during drying and firing;
3. materials containing feldspars (aluminosilicates of sodium, potassium, calcium, etc.) or carbonates (in particular, calcium), due to which the required viscosity is achieved during firing, which provides a vitreous and dense structure of the finished product.

The production of ceramic tiles consists of the following steps:

1. Clay mining. The production process begins in the quarries where the raw materials are mined. The types of clay used must have a strictly defined chemical composition; in the future, this largely determines the properties of the material and its behavior during pressing and firing. Clay goes to the factory, where it is stored in special containers. Each container has its own type of clay.
2. Mixture preparation. Clay is mixed with other components in a strictly calculated proportion, enters the pre-grinding area to a certain size and undergoes the following operations: 1) grinding; 2) mixing; 3) moisturizing. The preparation of ceramic mass, depending on the properties of the feedstock and the type of manufactured products, is carried out:
   - in a semi-dry way (by pressing from a powdered mass - the clay is first crushed and dried, then crushed and fed for molding);
   - plastic method (from dough-like mass by heat treatment - clay is crushed under pressure, then sent to a clay mixer, where it is mixed with additives until a homogeneous plastic mass is obtained);
   - wet way ( source materials crushed and mixed with a large amount of water (up to 60%) until a homogeneous mass is obtained, then the liquid mixture enters special tanks).
   To make the body of the tile (in production it is often called a biscuit, as it resembles a cake layer in color and shape), the raw materials are carefully crushed and mixed to obtain a completely homogeneous mass for subsequent molding.
3. Product molding. Two methods are used for molding - pressing and extrusion.
   During pressing, the powdered mass is compressed by the press in two directions, under high pressure the granules move and partially deform, due to which even unfired tiles have the appropriate density and strength.
   During extrusion, clinker tiles are made from a dough-like mass and are molded by forcing through a special extruder hole, having the shape of a future profile. Extrusion differs from dry pressing in that manufacturing process there is a so-called "liquid phase", when a viscous mass is squeezed out of a certain form under pressure and then cut off. It is these technological subtleties that allow the production of material various shapes, while by pressing it is possible to obtain only a flat tile of certain dimensions. Clinker tiles made by extrusion can be much thicker than pressed ones, moreover, convex or concave, which makes it possible to produce special clinker elements, for example, corner, external and internal.
4. Product drying. An obligatory intermediate operation of the technological process for the production of ceramic products is drying. Drying plays an important role, since at this stage water is removed from the product, which was necessary for molding. Drying conditions are extremely importance to ensure the integrity of the product, therefore, the process should be carefully controlled to avoid the formation of deformations, cracks and other defects. In the production of ceramic tiles today, the most common are dryers with hot air drying. Such an installation provides moisture to the surface of the product, its further evaporation and removal. The speed of the installation (the drying process lasts several tens of minutes) is ensured by good heat transfer, efficient ventilation and relatively high air temperature, at which the drying is performed. If the raw material, which has a high moisture content, is fired immediately after molding, it will crack. Further, in the process of drying and final high-temperature firing, the “shrinkage” of the tile takes place (a proportional decrease in linear dimensions), this is exactly what explains the presence of calibers assigned to the tile - in fact, the designation of its actual size. This is due to the fact that it is impossible to foresee this decrease in the firing process with an accuracy of a millimeter, it depends on many factors. Therefore, in the future, at the final stage, the tiles are sorted according to the actual size (caliber), which in turn has small tolerances, according to ISO standards.
5. Application of glaze (enamel). Glaze (from the German Glasur, from Glas - glass) is a vitreous protective and decorative coating on ceramics, fixed by firing (transparent or opaque, colorless or colored). Glaze is a mixture of various minerals and compounds (frits, sand, various oxides, coloring pigments, which are applied to the surface of the product and melted). Glazes are different kind, colored or non-colored, matte and glossy, even transparent. The color of the glaze is achieved by adding salts and metal oxides, for example, cobalt gives blue color, chrome - green, iron - red. Tiles can be glazed or unglazed. In glazed tiles, the upper, relatively thin layer has a vitreous structure, that is, the surface of the tile differs from its base and provides a visual effect (color, gloss, ornament, etc.), as well as a number of properties, such as water resistance, hardness, etc. which the tile base cannot provide. Thus, a glazed tile contains two layers with different structures: the glaze on the surface and the base below. Unglazed tiles, on the contrary, have a uniform structure throughout their thickness. To date, there are several dozen ways to apply glazes to the surface of ceramic tiles. Glaze can be applied in the form of granules, pasty mass or spray suspension. Technologically, enamel is applied using a machine - a large round drum, the circumference of which is several times greater than the length of the tile. The drum, rolling, applies liquid enamel, and since the length of its circumference is much greater than the length of the tile, 3-4 tiles are processed in one revolution. The moment of application can occur in different ways: before firing, after firing and even during firing. To give the tile a more aesthetic appearance, the glazing process can be used in conjunction with the application of various images. Often, an axial displacement of the drum is used in order to make a large number of tiles with a non-repetitive pattern, while maintaining the selected design and color of the series.
6. Burning. By firing tiles, as well as others ceramic products acquires mechanical characteristics that make it suitable for various uses. These characteristics are the result chemical reactions and the physical changes that occur both in the tile itself and in the glaze (in the case of glazed tiles). Firing is carried out in kilns continuous action, which are a tunnel through which the tile moves on special conveyors, while being preheated, as a result of which moisture evaporates, then the tile is fired at a temperature, depending on the type of product, from 900 to 1250 ° C or more. A characteristic property of clays is their ability to turn into a stone-like mass during firing. For each type of tile (and sometimes for each collection) an individual temperature regime. different and Maximum temperature firing for different materials. For double firing tiles - about 950 ° C, for single firing - up to 1180 ° C, for porcelain stoneware - up to 1300 ° C. After staying for a certain time in the firing section, the tile moves further along the tunnel, successively cooling down to a temperature that ensures its safe unloading from the furnace. After cooling, the tile acquires a structure with high mechanical strength.
7. Sorting. Before entering the packaging area and further to the warehouse, the tiles are carefully sorted. This process is designed to achieve three goals: 1) reject defective products; 2) to separate tiles of the first grade from tiles of lower grades; 3) group the tiles of each grade into trade lots in terms of dimension (caliber) and color (tone). The sorting order can be as follows: after leaving the oven, the tile comes to the area for flaw detection and calibration, and then visual control of the tonality. Tests at the flaw detection section consist in the fact that each tile falls on the so-called rails located along the edges of the tile and a roller is rolled in the center, acting on the tile with a certain load. If the tile has a defect, then it does not withstand the load and breaks, automatically not falling into further tests. Enamel surface defects are checked visually, at the same time as determining the tonality of the tile. Next, the tiles are sorted into batches, packed, labeled and delivered to the finished product warehouse.

Types of ceramic tiles

Each stage of production for various kinds tiles has its own characteristics, which further determine the characteristics of the resulting material.

BIKOTTURA

Enamelled ceramic tiles designed for indoor wall cladding. Enamel gives the tile shine and allows you to display the pattern of any design, and also protects the ceramic body of the tile from moisture penetration. The body of the tile, the so-called "cookie", is obtained by pressing a moist mass of red clay under pressure in special molds, followed by firing at a temperature of up to 1040 ºС. The entire production cycle of this type of tile takes place in two processes: 1) to create the base, only the base of the tile is fired, firing is carried out at low temperatures. The result is a highly porous shard (with a water absorption index of up to 10%), which has not undergone shrinkage and does not require further sorting of tiles by size (calibration). At the end production cycle the tile passes the control of planometric parameters and linear dimensions. In case of non-compliance of the tile with the specified parameters, it is automatically removed from the conveyor and goes for processing. 2) To fix the enamel, glaze is applied to the base and secondary firing takes place, characterized by an even lower temperature (700-900 ºС). Only previously selected high-quality tiles are allowed to the second phase of firing - the enameling phase. The general meaning of staged firing is to provide the necessary strength characteristics of the "biscuit" (high temperatures are required), and to preserve the color of the desired brightness and saturation (at low temperatures, coloring pigments practically do not fade). The thickness of the "cookie" is 5-7 mm, it is inferior in strength to other types of tiles and has an interior application. The enamel covering double-fired tiles is either glossy or matt and does not have high surface strength, since this tile, used mainly on walls, is not expected to be subjected to mechanical and abrasive loads (it will not be walked on). The exception is some series of tiles recommended by manufacturers and as floor tiles. Since the process of applying enamel does not affect the geometry of the tile in any way, these parameters are no longer controlled after the end of production, the tile is checked for surface defects. The main formats for the production of tiles: 20x20 cm, 20x25 cm, 25x33.3 cm. Outwardly, bicottura can be distinguished by: relatively small thickness; red-brown clay base; light weight; glossy shiny enamel.
Bicottura is usually made in collections consisting of several colors: lighter - most often basic in a series and additional - darker and with a large number of decorated elements. Decorated items are made in the following ways:
- using an additional third firing: a pre-made tile is cut under right size(for example, a border). The necessary pattern is applied to the finished tile. It's done different ways depending on the expected effect - drawing a pattern through grids or stencils with paints, gold, glaze (sometimes in the form of powder). Next, another layer of enamel is applied to the product, followed by firing at an even lower temperature (up to 700 ºС) to fix the pattern, while the glaze powder melts, forming a relief pattern.
- with the help of gypsum: for the manufacture of relief decorative elements of large thickness, gypsum is added to the batch, which gives plasticity, then molding takes place, followed by enameling and firing (sometimes drying without firing).

MONOKOTTURA

This is an enameled ceramic tile designed for both wall cladding and floor tiling. Some of its types are frost-resistant and, accordingly, allow the use of this series indoors and outdoors. The entire production cycle of monocottura takes place in one firing process. A specially prepared mixture, consisting of different types of clay with the addition of other natural ingredients, is mixed in special containers and moistened at the same time. Then it is dried and ground in huge vertical drums almost to the state of suspension, and under pressure it is fed into the mold. The size of the pressed tiles at this stage exceeds the nominal size by about 7-10%, i.e. the ceramic tile, which has a catalog size of 30x30 cm, still has a size of approximately 33x33 cm. This is because the tiles narrow during the final firing and drying process. , proportionally decreasing in linear dimensions. Next, the ceramic tiles are sent to a special final drying chamber and to the area where enamel is applied to the tiles that have not yet been fired, which, after firing, protects the structure of the tiles and gives the originally intended color and design of the tiles. After applying the enamel, the tile is sent to a furnace up to 100 m long. Gradually heating up there to a temperature of 1200 ° C and then gradually cooling down, the ceramic tile undergoes the same single firing, as a result of which the base becomes extremely hard and the enamel is fixed on it, forming a strong tile with the tile. a single whole. After leaving the furnace, the tiles are sent to the area for flaw detection and visual control of tone and calibration, after which they are sorted into batches, packed, labeled and sent to the finished product warehouse.
The main differences between bicottura and monocottura are: greater hardness (density) of the material as a result of using a more powerful press and a higher firing temperature, the presence of series with low water absorption (<3%), морозостойкими качествами (некоторые типы плитки одинарного обжига производят специально для эксплуатации при минусовой температуре, такой плиткой можно облицовывать постройки снаружи), более толстая и прочная основа плитки, более твердая, износостойкая эмаль. Плитка одинарного обжига подвержена усадке, поэтому могут встречаться расхождения в размерах (калибрах плитки), которые отличаются в разных партиях. Эмаль у плиток одинарного обжига, кроме повышенных прочностных характеристик, обладает стойкостью к бытовым моющим средствам, а некоторые виды этой плитки обладают также повышенной стойкостью к агрессивным химическим средам.
Decors for monocottura are produced in two types: floor and wall. The production of floor decors is very similar to the production of the base material, with the only difference being that a pattern of a given design is applied to blanks of the required size, which is then also fired, and therefore the hardness of the decor enamel is not inferior to the strength of the base field. Wall decors are made using the same technologies as for bicottura, respectively, without having the strength characteristics of the base material. In many cases, monocottura ceramic tiles are offered as floor tiles in matching colors and sizes for some bicottura series, thus complementing them.
There is also a special subtype of monocottura produced in the 10x10 cm format. Tiles of this format are recommended, as a rule, for facing the “apron” in the kitchen (decorating and protecting the wall between the lower furniture tables and the upper cabinets) and have a smaller thickness (about 6 mm) and more number of different decors. Since this ceramic tile is mainly used in the interior, it does not have all the advantages of monocottura (softer parameters are used in pressing and firing), but, nevertheless, it is stronger than bicottura and can be used as flooring in private interiors ( cottages, apartments, etc.).

MONOPOROSIS

A separate type of single-fired tile is produced using the technology of pressing and subsequent single simultaneous firing of the tile body and the applied glaze. In the production of monoporosa, clay with a high content of carbonates is used. This product is highly porous and has a high water absorption rate - up to 15%. The thickness of the base is 12 mm, because the strength of such a tile is less than that of a monocottura. Monoporose production technology makes it possible to produce large slabs. Since a white mixture is used in the production, this allows you to apply a thin layer of light enamel. This is very advantageous because, for example, bicottura, which has a red base, requires a thick layer of a light coating. Therefore, the most common are colors that mimic marble. The surface of the tile is decorated both in the traditional way - by drawing a pattern on the product, and by cutting under high pressure water on special equipment, so you can get a beautiful prefabricated decor, including pieces of natural stone. Such tiles are less dense than monocottura, and can only be used for interior decoration.

GRES (Ceramic granite)

Solid Colored Porcelain Granite is a non-enamelled, single-fired ceramic tile made from light-coloured clays. The mixture from which gres tiles are made consists of clays of several varieties, quartz sand, feldspar and coloring pigments (metal oxides) - natural components that, unlike natural stone, do not serve as a source of increased radioactive background and are a material that is safe for health. The production phases of ceramic granite are similar to those of monocottura. The mixture is pressed, dried, and then fired at very high temperatures. In this case, the starting material is sintered and forms a monolith. Thanks to this, porcelain stoneware has high technical characteristics, such as: low water absorption rate - less than 0.05%, resistance to chemical attack, increased resistance to abrasion, impact strength, bending strength, resistance to temperature changes, clarity of pattern and color, coloring product does not change under the influence of external factors. According to the type of surface, ceramic granite is divided into several main types:

1. Matte - tiles with such a surface are not further processed after leaving the oven, so they have a natural look.
2. Polished - the raw surface of the gres is cut evenly and then brightened. As a result, the tile becomes sparkling. After polishing, a composition is applied to the product, which closes the micropores and makes the surface less susceptible to contamination. However, such a tile has several disadvantages (if water gets on it, it becomes very slippery, besides, it is very easy to scratch it, so the polished gres should be monitored especially carefully and cleaned with special non-abrasive liquid detergents).
3. Semi-polished (lapped - from the Italian lappato - lapped, smoothed) porcelain stoneware - is obtained by cutting off a smaller upper layer of gres using surface grinding technology (special grinding stones are used for this). Usually uneven tiles are treated in this way, resulting in a spectacular combination of polished and matte areas. The surface of lappated ceramic granite is easier to clean from dirt. Lapatated ceramic tiles differ from polished tiles in less intense tile processing, as a result of which the tile acquires a shine and a non-slip surface.
4. Smalted ceramic granite (gres porcelanato smaltato) has become widespread. Its manufacturing technology is very similar to the production of monocottura - the applied enamel, which determines the color and texture of the surface, is fired together with the tile as a result of a single firing, but at the same time the material has the same high strength and frost-resistant characteristics as porcelain stoneware.
5. Retification is another technology for processing ceramic granite. Retification is an additional mechanical processing of an already finished material, which consists in cutting the side edges on each side of both matte and polished tiles on special machines (using diamond wheels) to give all tiles in the series, without exception, the same size in each format and equally smooth edges of the product. This operation allows you to lay tiles of different sizes, as well as to combine matt and polished tiles of the same series with minimal joints from 1mm, which is an additional advantage and is almost impossible for non-refined tiles. Nevertheless, it is still recommended to lay such a tile with a seam - so that when the building shrinks, or when the tile expands (for example, from temperature changes), it does not crack.

COTTO

These are usually unglazed single-fired ceramic tiles. It is made from red clay by extrusion - punching through a square, rectangular or, for example, hexagonal shape. Cotto is mainly used for flooring. The extrusion method allows you to get tiles of the most bizarre configuration. The most popular sizes: 250x250, 300x300, 200x400 and 400x600 mm. The body of the cotto has a variety of natural colors of yellow, brown and reddish. The front surface is usually processed with special brushes, as a result of which hard bumps appear on it. Finally, the surface of the cotto can be polished, polished or, conversely, made deliberately rough. The main technical characteristics of cotto: low water permeability and abrasion, resistance to compression and bending, resistance to chemical and atmospheric influences.

CLINKER

Clinker is a single-fired ceramic tile with a densified base, in the manufacture of which the extrusion method is used, as well as pressing technology (for example, at the Paradyz factory). Sometimes it is enameled or covered with the so-called "salt" - a thin layer of transparent glass. The main characteristics of clinker: high resistance to mechanical stress, low abrasion and water permeability, resistance to chemical attack, resistance to temperature extremes, frost resistance. Typically, clinkers are used for flooring both inside and outside, as well as in the construction of swimming pools - in the decoration of plinths, corners, drains, steps and various connecting elements.

MAJOLICA

A large-pored tile with a colored base and a front surface, as a rule, covered with an opaque glaze, on which a bright pattern is applied. For the production of majolica, quarry clays containing sand, carbonate fractions and iron oxides are taken. The tile is obtained by pressing followed by double firing. Majolica is distinguished by high mechanical strength and resistance to the formation of craquelure (small cracks on the surface of the paint layer in painting - in old paintings on canvas and wood, as well as on ceramics, enamel, glass), but due to the porous base, majolica easily absorbs water, therefore can only be used for finishing interior walls in dry rooms. Despite the limited area of ​​​​use and energy-intensive double firing, majolica is in steady demand due to its high decorative qualities, strongly associated with antiquity.

General recommendations for the selection and use of tiles can be formulated as follows

Bicottura - used for wall cladding in interiors, sometimes for flooring (if the selected series is recommended for such use), but only in those rooms that are not directly connected to the street and where, as a result, there is no risk of damaging the enamel with mechanical particles (sand, dust).
Monocottura - used for cladding all types of surfaces in interiors, and especially resistant types of this tile can be used as a floor covering in public places with not very intensive traffic (after all, it should be borne in mind that enameled ceramic tiles will wear out faster during operation one way or another than porcelain stoneware dyed in mass). Also frost-resistant series can be used for outdoor and indoor work.
Porcelain stoneware dyed in mass - cladding of all types of surfaces both indoors and outdoors. It has practically no restrictions on its use - it can be private interiors, restaurants, airports, swimming pools, sidewalks, etc. It is only worth noting here that for some outdoor works and floors in special rooms it is necessary to select tiles with an appropriate anti-slip surface (for stairs) or streets, special rooms (warehouses, production workshops). Choice of polished porcelain stoneware tiles: due to the very smooth surface of this material, it is mainly used in indoor areas where there is no danger of water getting on it, which makes it very slippery. You also need to take into account the fact that the use of this material in places that have direct contact with the street (restaurants, cafes, lobbies) exposes it to additional wear, as it will be more subject to mechanical stress and may lose its appearance over time.

Properties and features of ceramic tiles

Ceramic tile is a very durable material. If the tile is correctly laid, then its tensile strength is 10–20 times higher than the similar limit for cement or reinforced concrete - it can reach 30 thousand tons per square meter! The high rigidity index allows ceramic tiles not to bend or deform even under very high tensile loads. And the thicker it is, the higher this figure. The vitreous surface of the ceramic tile (glaze or enamel) protects the ceramic tile from water. This material has properties of fire resistance and fire resistance, thanks to which the tile can be used for lining stoves and fireplaces. It does not burn, protects the lined surface, and does not emit toxic substances when heated. The tile is not subject to destruction in contact with chemicals (the only threat is hydrofluoric acid). When in contact with ceramic tiles, there is no discharge of static electricity, as is the case with synthetic surfaces (carpet, linoleum), that is, the tile is a dielectric. Ceramic tiles are made from natural ingredients and are environmentally friendly. Ceramic tile quickly absorbs and conducts heat, that is, it has a high thermal conductivity. It is one of the most hygienic materials and is very easy to keep clean.

1. Wear resistance is one of the most important qualities of floor tiles, which characterizes the resistance of tiles to abrasion and the ability to keep their appearance unchanged. Researchers at the American Institute of Porcelain and Enamel, who analyze, test and research ceramic materials, have developed a classification of tiles according to the degree of abrasion. It is abbreviated as PEI and is used to correctly select tiles of a certain wear resistance group, depending on the type of premises in which they will be laid. If you put a tile of an inappropriate group on the floor, it will wipe off very quickly, lose strength, become covered with scratches, and the glaze will lose its luster. The PEI classification includes five groups: PEI I - tiles of this group assume a light degree of exploitation without exposure to abrasive particles (used for walls in bathrooms). PEI II - tiles of this group require operation with a small presence of abrasive particles (used for walls / floors in bedrooms, offices, bathrooms). PEI III - tiles of the third group fit in any residential premises and in small offices that do not have a direct entrance from the street. The tile is not suitable for stairs, corridors and other areas with high traffic. PEI IV - tiles of this group have higher strength characteristics than the tiles of the previous group, and therefore are suitable for any living rooms, as well as for covering stairs, halls, corridors. PEI V - Tiles of the fifth group are the most durable and abrasion resistant glazed tiles. Therefore, only it is used both in private and public interiors with above-average traffic (offices, shops, cafes, restaurants). For places with heavy traffic (traffic), it is recommended to use unglazed porcelain tiles (airports, train stations, shopping centers).
2. Water absorption - the ratio of the mass of water absorbed by the sample when it is completely immersed in water, to the mass of dry matter. The ratio is expressed as a percentage. The water absorption of glazed ceramic floor tiles must not exceed 3% (standard EN 176 Bl), for wall tiles the water absorption must be at least 10% (standard EN 159 BIII). The water absorption index of the tiles plays an important role in the lining of swimming pools. For this, it is necessary to use only special tiles, such as porcelain tiles, clinker, porcelain tiles.
3. Frost resistance - the ability of a tile to resist temperature changes. Water absorption and frost resistance are interrelated characteristics that directly depend on the porosity of the tile. When firing any ceramic tile, no matter what technology is used, pores form in its body - from the evaporation of residual moisture, from the release of gases formed during high-temperature chemical reactions. Naturally, moisture from rain, fog, snow can penetrate into them - if the tiles are laid on the street, or from various technological liquids - if, for example, a refrigerator is lined with tiles. Frost resistance - the ability of ceramic products saturated with water to withstand repeated alternate freezing in air and thawing in water without signs of destruction and without a significant decrease in strength, in other words, the frost resistance indicator is resistance to cyclic freezing and thawing. European testing methods stipulate that 25 freeze / thaw cycles at a temperature of -15Cº to +15Cº (at a temperature of -20Cº to +25Cº according to GOST 7025-91) is sufficient to establish the presence or absence of resistance. The resistance of ceramic tiles is determined by two parameters: the presence and number of pores. Double-fired tiles are quite porous and therefore not frost-resistant. A single-fired tile with a water absorption of less than 3% is considered frost-resistant. Porcelain stoneware, unlike ceramic tiles, has the lowest level of water absorption - less than 0.05%, which is characterized by the absence of pores and microcracks on the surface and resists the penetration of water inside, does not expand and does not cause destruction during frost. Frost resistance must also be taken into account when the tiles are laid outdoors or in an unheated room where the air temperature drops below 0C.
4. Cracking is the appearance of fine cracks in the enamel coating. This happens with poor-quality or improperly selected tiles under the influence of sudden changes in temperature. Such a defect is sometimes present on the tiles before laying. If it can be proven that the "crack resistance" standard was violated in the manufacture of the tile, the defect is considered a manufacturing defect. When the tile cracks some time after laying, the cause may be improper tiling: the use of a bad mortar or adhesive, too thick or thin layer of these materials.
5. Slip resistance is a characteristic that determines the ability of a surface to prevent an object placed on it from sliding. It is expressed by the coefficient of friction, which is most often measured by the German DIN standard method. The result of the test is expressed in terms of the angle of inclination of the floor at which the object begins to slide. Slip resistance is a basic requirement for the safety of residential and industrial premises, as well as for outdoor flooring. In baths, saunas and pools, ribbed tiles with grooves are usually laid.
6. Chemical resistance is a characteristic of tile enamel, reflecting its ability to withstand contact with chemicals at room temperature. Chemicals include acids, salts, bases, as well as household chemicals, pool additives, and household products. The tile must resist the aggressive or mechanical action of these substances without undergoing external changes. According to the EN 122 standard, the following classes of tiles are distinguished in terms of resistance to aggressive environments (environments that cause the destruction of materials and deterioration of its properties - the use of household detergents, atmospheric exposure): Class AA - during testing, the tile completely retained its appearance, Class A - appearance changed slightly, Class B - significant changes in appearance were revealed, Class C - there was a partial loss of appearance, Class D - the original appearance was completely lost. You should not forget about the seams on the tiled surface. They can be protected by filling with epoxy materials that resist chemical attack well.
7. The tone and caliber of the tiles. Hue - the color saturation of the tile, which may slightly differ from the declared color. It is indicated on the packaging by a number or a letter. Caliber - the actual size of the tile, which sometimes differs by a couple of millimeters from the nominal. The caliber is indicated on the package next to the nominal size. Slight discrepancies in size often occur when producing tiles with a very dense backing. During production, the tiles are sorted into batches of the same size with a tolerance for the difference established by the regulations. Before laying, the tiles should be checked for discrepancies with the size/gauge comparison indicated on the packaging, otherwise even slight deviations may cause unevenness or other defects in the coating.
8. Bending resistance is a characteristic that determines what limit value of a static load applied to three points of one ceramic tile, it can withstand without breaking. The resistance to bending is higher, the lower the water absorption of the tile. Porcelain stoneware has a very high bending resistance, while porous tiles have a lower bending resistance.
9. Tensile strength - the level of possible load that the tile must withstand. It directly depends on its thickness. The ability to withstand loads is especially important for floor tiles. Loads such as the weight of a person or furniture, the tiled flooring must withstand easily and not break.
10. Surface hardness is a characteristic that expresses the ability of a surface to be resistant to scratches and damage. In accordance with the EN101 standard, tiles are classified on a scale of 1 to 10, according to the increasing hardness of the minerals used for the test. Scratches are clearly visible on the shiny surface of the tile, but they are less noticeable on the matte surface.
11. Resistance to temperature extremes is the ability of the enamel surface not to undergo visible changes due to the "shock" caused by a sudden change in temperature through successive cycles of immersion in water at room temperature and subsequent placement in an oven with a temperature of over 105°C. The test shows the greater or lesser resistance of the tile to such influences.

Ceramic tile is the cladding material that is present in every home. Coming to the salons, we evaluate the colors, design, sizes, shapes, without even thinking about how the tile that we now hold in our hands is actually produced. But this is a very interesting process, and believe me, the modern production of ceramic tiles has its own secrets.

Composition of ceramic tiles

Raw materials for the production of ceramic tiles are mixtures of various materials, through the use of which the technical, aesthetic and operational characteristics of the product are ensured:

• clay materials provide the plasticity of the wet mass, necessary for the molding of tile blanks;
• quartz raw material- quartz sand, which forms the "skeleton" of ceramic tiles, performs the structural function necessary to control and limit the dimensional changes of the tiles that inevitably occur during drying and firing;
• materials containing feldspars (aluminosilicates of sodium, potassium, calcium, etc.) or carbonates (in particular, calcium). Due to these materials, during firing, the required viscosity is achieved, which provides a vitreous and dense structure of the finished product.

Production process of ceramic tiles

1. Clay mining

The production process begins in the quarries where the raw materials are mined. Clay grades must have a strictly defined chemical composition, since it largely determines the properties of the material and its behavior during pressing and firing. That is why leading manufacturers carry out strict control of this stage. The quality of raw materials is controlled both during collection and delivery to the factory. Having arrived at the factory, the clay is stored in special containers: a separate container is intended for each type of clay.

On a note: Manufacturers use different grades of clay. Most of the Spanish factories "work" with red clay, since Spain has rich deposits of this raw material. But the highest quality is white clay, it provides the best performance and a high level of stability of the product.

For example, the Aparici factory works mainly with white clay and they bring it from Australia.

Among the factories that use only varieties of white clay in the production process are Porcelanosa and Venis. For Porcelanosa, clay is mined in England, Ukraine, Belgium, Turkey and Holland.

2. Preparation of the mixture

At the second stage, clay, in strictly calculated proportions, is mixed with other components. Different types of mixture are used to produce certain colors, formats and patterns of tiles.

The resulting mixture enters the pre-grinding section and undergoes the following operations:

• grinding
• mixing
• moisturizing

To make the body of the tile, which is also called the "biscuit", the raw materials are carefully crushed and mixed to obtain a perfectly homogeneous mass.

Today, there are three types of technologies for the preparation of ceramic mass. The choice of one technology or another depends on the properties of the feedstock and the type of product being manufactured.

• Semi-dry method, i.e. pressing from powdered mass. To do this, the clay is first crushed and dried, after which it is crushed and fed for molding.
• plastic way- from dough-like mass by heat treatment. First, the clay is crushed under pressure, then it enters the clay mixer, where it is mixed with additives until a homogeneous plastic mass is obtained.
• Wet way. The raw materials are crushed and mixed with a large amount of water (up to 60%) until a homogeneous mass is obtained. After that, the already liquid mixture enters special tanks.

3) Product molding

The resulting homogeneous mass goes through the next stage of the production process - the molding of the product.

There are two molding methods - pressing and extrusion.

Pressing allows you to get only a flat tile of a certain size; extrusion also provides the production of material of various shapes, including convex or concave.

Product molding by pressing: the powdery mass is compressed by a press in two directions. Under high pressure, the particles move and are partially deformed, due to which even unfired tiles already have the appropriate density and strength.

Product molding by extrusion: clinker tiles are made from a dough-like mass, which is pressed through a special extruder hole that has the shape of a future profile. There is a "liquid phase" in the manufacturing process: a viscous mass is squeezed out of a certain shape under pressure and cut off. It is due to this moment (which is not present in molding by pressing) that the extrusion method ensures the production of material of various shapes.

Such tiles can be much thicker than pressed ones, they can be convex or concave, which makes it possible to produce special clinker elements - corner, external, internal.

The material obtained at this stage is still very soft, it is easy to break it with your hands.

4) Product drying

This is an obligatory process for the production of ceramic tiles, since if a material with a high level of moisture is sent for firing immediately after molding, the product will crack.

Due to drying, the percentage of water that was necessary for its molding is removed from the product. The integrity of the tiles depends on drying (the absence of deformations, cracks and other defects), so this process is very tightly controlled.

Drying can be carried out by different methods, but in modern production plants with hot air drying are most often used. They provide moisture to the surface of the product, its further evaporation and removal. The drying process takes several tens of minutes. The speed of the process is achieved due to good heat transfer, effective ventilation and relatively high air temperature during the dehumidification of the material.

In the process of drying and final high-temperature firing, the “shrinkage” of the product occurs, i.e. proportional reduction in linear dimensions. At the same time, it is impossible to foresee the actual reduction in size with an accuracy of a millimeter, it depends on many factors. This explains the presence of calibers, i.e. designations of the actual size of ceramic tiles. The definition and assignment of calibers to the finished product occurs at the sorting stage.

On a note: many Porcelanosa collections are not dried in the traditional sense. The material dries naturally, reaching the desired state. Of course, this requires special conditions and time, but such material is considered more natural, of better quality.

5) Application of glaze (enamel)

Ceramic tiles are always glazed. Porcelain stoneware can be glazed and unglazed. In glazed tiles and glazed porcelain stoneware, the upper relatively thin layer has a vitreous structure. That is, the surface of the tile is different from its base and provides a visual effect (color, gloss, ornament, etc.), as well as a number of properties, such as water resistance, hardness, etc., that the base of the tile cannot provide. Thus, a glazed tile contains two layers with different structures: the glaze on the surface and the base below. Unglazed porcelain stoneware, on the contrary, has a uniform structure throughout its thickness.

What is glaze in ceramics? Glaze (from the German Glas - glass) is a vitreous protective and decorative coating on ceramic products, fixed by firing. This coating may be transparent or opaque, colorless or tinted, matte or glossy.

The composition of the glaze is a mixture of various minerals and compounds, such as coloring pigments, frits, various oxides, sand. The color of the glaze is given by various salts and metal oxides. For example, chromium will give green color, iron - red, cobalt - blue.

The prepared mixture is applied to the surface of the product and melted on it during the firing process.

There are three main ways to apply glaze to the surface of ceramic tiles: using the "drum", "dome" and digital printing.

Glazing can be applied to tiles before firing, during firing, or after firing.

Glaze can be applied in the form of a pasty mass, granules, in the form of a sprayed suspension. The glazing process is carried out using a machine, which is a round drum with a circumference several times the length of the tile. The drum, rolling over the tile, applies liquid enamel to the surface of the product, and since the length of its circumference is several times greater than the length of the tile, 3-4 products are processed in one revolution.

The glazing process can be combined with the drawing process. Most often, the axial displacement of the drum is used for this, which allows the production of a large number of tiles with a non-repeating pattern. But the design and color is preserved for the entire collection.

Another way of applying the glaze is done with a machine in the form of a "dome". At the same time, the machine does not touch the surface of the tile, it “poureds” the surface of the product with the prepared mixture from above.

The digital printing method offers a number of advantages over the other two printing methods:

• Provides very high print quality
• makes it possible to decorate embossed surfaces;
• provides reproduction of natural and other textures in photographic quality;
• allows you to quickly create new designs;

On a note: Currently, ceramic tile manufacturers either buy a ready-made glaze (the actual mixture that will be applied to the tile) or develop it themselves. For example, the Peronda factory presented a new collection with an exclusive coating resembling crystallin. This is a development of the factory itself and currently other manufacturers do not have such glaze.

Among the well-known manufacturers of various types of glazes for the ceramic industry, Torrecid can be noted. The current direction of Torrecid is the production of glaze for digital technologies.

6) Firing

Due to firing, ceramic tiles acquire the mechanical characteristics necessary for its subsequent operation. At high temperatures in the tile (and if the tile is glazed, then in the glaze) a series of chemical reactions and physical changes take place. When fired, the clay turns into a stone-like mass.

Roasting takes place in continuous kilns, which are tunnels through which tiles move on special conveyors. During the firing process, the tile is preheated, due to which the last remaining moisture evaporates, and then the products are fired at a temperature of 900 to 1250 ° C and above. The choice of temperature will depend on the type of product. For each type of tile, an individual temperature regime is developed.

The temperature in the oven rises gradually: the tile heats up from a lower temperature to a higher one. Otherwise, the product would immediately crack.

Different materials have their own maximum firing temperature. So, for double firing tiles - about 950 ° C, for single firing - up to 1180 ° C, for porcelain stoneware - up to 1300 ° C. After staying in the firing area, the tile moves through the tunnel, successively cooling down to the temperature necessary for its safe unloading from the furnace. After cooling, the tile acquires a structure with high mechanical strength.

On a note: It takes approximately 55 minutes for a tile to pass through the oven at Porcelanosa (from start to finish). Each sector of the oven is connected to its own computer, each sector has its own temperature, for example, in the middle of the oven - about 1200°C.

7) Sorting

Before the tiles arrive at the packaging area and then to the warehouse, they go through a sorting stage. The following tasks are performed here:

• rejection of products with a defect;
• tiles of the first grade are separated from tiles of lower grades;
• tiles of each grade are grouped into trade lots, based on the tonality (color) and caliber (actual dimensions);

After leaving the furnace, the tile goes to the area of ​​flaw detection and calibration, then goes to the visual control of the tonality.

At the flaw detection section, each tile passes along special “rails”, a roller is rolled through the center of the product, which exerts a certain pressure on the tile. In cases where a product has a defect, it breaks and automatically does not fall into further testing.

At the site of visual control of the tonality, defects in the enamel surface are checked, respectively, if they are present, the tile is rejected. And at the same stage, the tone of the tile is determined.

On a note: Previously, visual control of the tonality was performed by people. Today, the production of many factories is automated to such an extent that this work is done by machines, and they are controlled by, say, one person. For example, at the Aparici factory, colors are compared by a special machine, the quality of which is monitored by a factory employee. In principle, such machines are quite accurate, so control over their work is optional, but recommended.

Man has always sought to decorate his home and make it practical. For these purposes, he uses various materials, many of which have remained relevant for millennia. So, the first prototypes were found at the excavations of the Euphrates and Mesopotamia Tigris. In ancient times, this material was used to decorate the walls of temples and houses of the nobility. Over time, its popularity grew, and manufacturing methods improved. Let's take a closer look at modern ceramic tiles and find out how it has earned such an impeccable reputation.

Compound

First of all, let's figure out what ceramic tiles are made of. The main raw materials used in the production of ceramics are represented by the following materials:

1. clay materials. They give the wet mass the plasticity necessary for molding blanks.
2. Quartz materials (mainly sand). They perform a structural function, that is, they create the "skeleton" of the product. They allow to limit and control the change in the dimensions of the product, which inevitably accompanies the firing process.
3. Materials containing feldspars (aluminosilicates or carbonates of potassium, sodium, calcium, and so on). With their help, when the product is fired, its structure remains dense and vitreous.

The manufacturing process of ceramic tiles consists of the following stages:

1. Mixing materials.
2. Molding.
3. Drying.
4. Applying glaze.
5. Burning.
6. Sorting.

We will dwell on each of the stages separately.

Material mixing

It all starts with the extraction of materials, but we will not consider it, since we are interested in the process of manufacturing ceramic tiles. First of all, clay is mixed with the rest of the components according to strictly calculated proportions. The finished mixture enters the preliminary grinding, where it is crushed and moistened.

The method of preparing the ceramic mass depends on the properties of the raw material and the desired product. There are such ways:

1. Semi-dry. The components are first crushed, then dried a little, crushed, mixed and sent for molding. This method is called semi-dry because the components themselves have a certain degree of moisture.
2. Plastic. Clay is crushed and sent to a mixer, where it is mixed with additives and takes the form of a homogeneous plastic mass.
3. Wet. The materials are crushed and mixed with the addition of water (up to 60%). Homogeneous liquid mixture is fed into special tanks.

Regardless of which ceramic tile production line is used, to obtain a good product, it is necessary that all materials are carefully crushed and mixed.

molding

Forming is done in two ways: pressing and extrusion. In the first case, special presses squeeze the powdery mass in two directions. Being under high pressure, the granules are subjected to compaction and partially deformation. Due to this, the tile acquires the appropriate density and strength.

When using the extrusion method, the tiles are made from a dough-like mass, which is formed by forcing through the holes of the extruder. This method differs from dry pressing by the presence of a liquid phase in the production process. It is due to the fact that the viscous mass is squeezed out of the apparatus and cut off, it is possible to produce products of various shapes. made by extrusion, can be convex or concave. When pressing, only the size of the products can be varied.

Drying

An obligatory stage in the production technology of ceramic tiles is drying. At this stage, moisture is removed from the finished molds, which was necessary for comfortable molding. Drying conditions play a crucial role in ensuring the integrity and strength of the future product, so they are strictly controlled. Modern tile factories use dryers that blow hot air over the raw (molded wet product). Heating leads to the formation of moisture on the surface of the semi-finished product, which quickly evaporates and is removed by the ventilation system.

Good heat transfer, effective ventilation and high air temperature ensure the unit's speed. If you subject the raw material to firing, bypassing the drying stage, it will crack. At the final stages of drying and during the firing process, the tile shrinks, that is, a proportional decrease in its linear dimensions. This explains the need for calibration of finished products. The higher the level of the enterprise, the more likely it is that its products will have the same dimensions. Therefore, it is better to choose options in the middle price range (for example, from Shakhtinskaya ceramic tiles, Euroceramics, Sokol, etc.) than to get an uneven wall.

Glaze application

Glaze (enamel) - a vitreous coating that is applied to the front side of the tile and fixed during the firing process. Glazing is performed to decorate and strengthen the product. The composition of the glaze may include various materials and compounds (sand, oxides, frits, coloring pigments, etc.). It can be glossy and matte, colored and monochrome, and sometimes even transparent. Coloring is achieved by adding metal oxides and salts to the composition (iron-red, chromium - green, cobalt - blue, etc.). Enamel has a vitreous structure and differs from the base of ceramics not only in appearance, but also in characteristics, the most important of which is water resistance.

Today, a ceramic tile factory can use several dozen methods for applying glazes to its products. Enamel can be applied as a spray suspension, paste or granules. In the basic version, it is applied to molded blanks using a large round drum, which, making one circle, processes several tiles at once. Application can be made before or after firing, and in some cases even during firing.

In order for the product to have a more aesthetic appearance, the enameling process can be accompanied by an image. Ceramic tiles with a pattern are much more popular than plain ones. To ensure that each tile has a non-repeating image, but retains the style of the series, the drum is simply shifted along the axis of rotation. Of course, this applies to models with abstract pictures.

Burning

Ceramic tiles are fired to make them sufficiently hard and durable. This happens due to chemical and physical changes in the composition of the material and glaze, which take place under the influence of high temperatures. Typically, ceramic tile manufacturers use continuous kilns for this purpose. In fact, such an oven is a tunnel, moving through which, with the help of a special conveyor, the tile is first preheated (allows you to get rid of moisture residues), and then fired.

A characteristic property of clay is its ability to turn during firing into a strong stone-like mass. Depending on the type of product, the firing temperature ranges from 900 to 1300°C. After spending a certain time in the oven, the tile is successively cooled to a temperature at which, without compromising quality, it can be unloaded from the oven.

Sorting

Before entering the packaging line and warehouse, the finished tiles are carefully sorted. This procedure solves three problems:

1. Discard products with defects.
2. Separate tiles of the first grade from tiles of lower grades.
3. Group trade lots by grade and color.

Usually, manufacturers of ceramic tiles sort in the following way - after leaving the oven, it goes through three stages: flaw detection, calibration, visual inspection. To detect defects, each product is fed onto rails and rolled by a roller. Due to the fact that the rails are located along the edges of the tile, and the roller presses into the center, defective samples break, unable to withstand the load. Paint defects are checked visually, along with the definition of tone. It remains only to sort the products into batches and send them to the warehouse.

As you can see, the production technology of ceramic tiles is quite simple. However, in order to obtain a high-quality product, it is necessary to approach each stage with full responsibility and compliance with all technological rules. That is why many aspiring entrepreneurs who have opened a ceramic tile factory cannot achieve the proper quality of their products. Now we will briefly find out what properties ceramic tiles should have.

wear resistance

Of course, this is one of the most important qualities of floor tiles, as it characterizes its resistance to abrasion and the ability to maintain an attractive appearance after long-term use. Despite the fact that the material as a whole is quite durable, its type should be selected depending on the operating conditions. So, designed for a simple bathroom, patterned ceramic floor tiles placed in a public toilet will quickly wipe off and lose their appearance.

Water absorption

Water absorption is the ratio of the mass of water absorbed by the tile when it is completely submerged under water, to the mass of the dry product, expressed as a percentage. For the floor, it should not be higher than 3%. For wall stamps, this figure rises to 10%. In this regard, for facing pools, for example, not any tile is suitable. Large manufacturers, for example, the Shakhtinskaya Ceramic Tiles enterprise, can produce various types of specialized products at their facilities, from bath tiles to ceramics for swimming pools.

Frost resistance

As well as water absorption, this property depends on the porosity of the product. Regardless of the production technology, pores remain in ceramic tiles, into which moisture can penetrate. As you know, when water freezes, it expands in volume. The ability of a tile saturated with moisture to withstand frequent alternating freezing is called frost resistance. This indicator is important when choosing an outdoor finishing material. The fewer pores in ceramics, the lower its water absorption index, and the higher the frost resistance index.

Slip resistance

As you might guess, this property determines the ability of the tile enamel to prevent the objects on it from sliding. This requirement is important when finishing the floor of residential and industrial premises, especially those in which it is always humid. In pools and baths, ribbed tiles are most often used, which have increased slip resistance.

Chemical resistance

This is the name of the characteristic of tile enamel, reflecting its ability to tolerate contact with chemicals (acids, bases, household chemicals, additives for disinfecting water in pools, etc.). The tile should not undergo external changes under the aggressive influence of these substances. By the way, considering the resistance of ceramics to certain influences, one should not forget that the seams between the tiles can also be subject to destructive effects. To avoid this, they are covered with protective compounds.

Tensile strength

This indicator expresses the level of permissible load that ceramic tiles can withstand. Usually it is directly proportional to the thickness of the product. Load bearing capacity is important mainly for floor tiles.

Surface hardness

This characteristic illustrates the resistance of the surface to damage and scratches. It is especially important for floor tiles. Surface hardness is determined by the quality and composition of the glaze. It is noteworthy that mechanical damage is much more noticeable on a shiny surface than on a matte one.

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Introduction

Basic properties of building materials

Introduction

1. Product range

2. Technological part

2.1 Raw materials and semi-finished products

2.2 Choice of production method

2.3 Technological scheme for the production of ceramic tiles

2.4 Description of the technological scheme

2.5 Selection of the main technological and transport equipment

2.6 New in the technology of production of finishing materials and products

Conclusion

Bibliography

Introduction

Due to the huge volume of reconstruction of old and construction of new buildings, a wide variety of building materials and products is required.

The introduction of new technologies for the production of finishing works must begin with a serious and detailed study of them by bachelor students in the production of building materials, products and structures.

The particular relevance of these guidelines is caused by the training of specialists to perform an ever-increasing volume of repair and construction work and a significant number of objects carried out according to the principle of free spaces (without finishing the premises). According to an independent assessment, 60% of the country's housing stock is worn out by more than 40% and, therefore, modernization and major repairs of engineering systems are required, followed by finishing of the premises at a modern level.

Finishing work is the final cycle of construction work, on the implementation of which an opinion is created and an assessment is given to the completed construction object.

Preparation of the base of surfaces for finishing remains an important and responsible stage of finishing work. To a greater extent, the durability and quality of the finish itself depends directly on the quality of the base and not even so much on the finishing materials themselves. Knowledge of modern work technologies and high qualification of performers also ensure the achievement of a high quality result of finishing work.

The introduction of structures with decorative ready-made coatings, which exclude finishing, contributes to a decrease in the labor intensity of work. These are structures of various types of suspended, false, stretch ceilings, prefabricated office partitions and large-sized sheet materials with finished types of coatings.

The main task of the course work is a reasonable choice of a method for the production of a certain finishing material. The solution of this problem is preceded by the choice of the main material, raw material or semi-finished product, the development of a technological scheme of production, the choice of the main technological equipment.

The course work is an independent work of the student and must contain elements of new and original solutions to a given technological process in the production of finishing materials.

Topics of term papers are assigned in accordance with the practical tasks of the industry and must have industrial and scientific value.

The main topics of the course work are related to the development of modern methods for the production of finishing materials, with a variety of painting compositions, decorative plasters, wallpaper, ceramic tiles, facing panels, etc., new technologies for mechanized application of dry mixes, a variety of each type of finish, etc.

For the production of finishing materials, there are many technological redistributions. Therefore, the possible topics of the work are not limited to instructions, but can be supplemented at the request of the student or the decision of the supervisor.

The presented materials can serve as a basis for the study and practical use of new technologies and building materials, in an important matter - improving comfort, environmental friendliness and modern design of residential and public buildings.

Coursework allows you to consolidate and deepen knowledge in the discipline "Finishing materials" and is a confirmation that the student is able to apply the knowledge gained in solving a specific problem.

Basic properties of building materials

Density a quantity equal to the ratio of the mass of a substance to the volume occupied by it is called; expressed in kilograms per cubic meter (kg/m3).

True Density - the limit of the ratio of mass to volume of a body or substance, without taking into account the voids and pores in them.

Bulk density -- the ratio of the mass of granular materials, materials in the form of a powder to the entire volume they occupy, including the space between particles.

Average density - a physical quantity determined by the ratio of the mass of a body or substance to the entire volume occupied by them, including the voids and pores in them.

Relative density -- the ratio of the density of a body or substance to the density of a standard substance under certain physical conditions.

Porosity -- the ratio of the pore volume to the external volume (dimension) of the material. It is expressed as a percentage.

Porosity determines the basic properties of materials: strength, frost resistance, gas permeability, water permeability, etc.

Water absorption - the ability of the material to absorb and retain water. Water absorption is determined by the difference in the mass of a material sample in a water-saturated and absolutely dry state and is expressed as a percentage of the mass of dry material.

Water absorption by volume B is equal to the mass of water absorbed by the sample when it is saturated, divided by the volume of the sample.

The water absorption of the material by volume is less than 100%, and the water absorption by mass of very porous materials is more than 100%.

The ratio of the strength of a material saturated with water to its dry strength is called softening factor . The numerical value of this coefficient ranges from 0 to 1.

With a softening coefficient of more than 0.8, the building material is considered waterproof, with a coefficient of less than 0.7 - non-waterproof, and it is recommended to use it in wetted structures and structures with high humidity.

Moisture return - the ability of the material to give moisture when the environment changes. Moisture yield is characterized by the rate of drying of the material per day at a relative humidity of 60% and a temperature of 20 °C.

Humidity material in percent is determined by the moisture content related to the mass of the material in a dry state.

Water permeability - the ability of the material to pass water under pressure. Water permeability is characterized by the amount of water that has passed through 1 cm 2 of the surface of the material in 1 hour at constant pressure. The degree of water permeability of the material depends on its density and structure.

Adhesion - the ability of a material to adhere to the surface of another body. Quantitatively, it is characterized by the specific work expended on the separation of bodies. Adhesion is an important property of paint and varnish polymer coatings, anti-corrosion compounds, waterproofing and roofing emulsions and suspensions, etc.

Frost resistance -- the ability of a material in a state saturated with water to withstand repeated alternating freezing and thawing without visible signs of destruction and a decrease in strength.

Frost resistance is characterized by the number of sustained freezing cycles, determined by a decrease in the strength of the material by no more than 25% and a weight loss by no more than 5%.

The frost resistance of the material is checked by repeated freezing of samples at a temperature of -15...-20 °C and subsequent thawing in water at a temperature of 20...25 °C.

Thermal conductivity - the ability of a material to transfer heat through its thickness from one surface to the opposite due to the temperature difference.

Heat capacity - the property of a material to absorb heat when heated and give it away when cooled; characterized by a heat capacity coefficient equal to the amount of heat in joules required to heat 1 kg of material by 1 °C. The heat capacity per unit mass is called the specific heat capacity. The heat capacity of the material allows you to maintain the heat resistance of buildings.

Gas permeability - the ability of the material to pass gas or air through the thickness. The volume of gas passing through a layer of material is directly proportional to the wall area, gas flow time, pressure difference and inversely proportional to the wall thickness.

Sound transmission - the property of the material to transmit air and shock sounds. Enclosing structures of buildings are evaluated by soundproofing ability: a quantitative measure - decibel (dB). The soundproofing of the walls is characterized. an indicator of permeability from air sound, and interfloor ceilings - an indicator of sound insulation from air and shock sounds. For residential buildings, the sound insulation index from airborne sound of inter-apartment walls and interfloor ceilings must be at least 1 decibel, and the sound insulation index from impact noise of interfloor ceilings must be 0 (zero) decibel.

fire resistance - the property of the material to withstand prolonged exposure to high temperatures under load (without softening or deforming).

fire resistance - the property of a material to resist the action of fire during a fire for a certain time. It depends on the combustibility of the material, that is, on its ability to ignite and burn. According to the degree of combustibility, materials are divided into combustible, slow-burning and fireproof.

elasticity a solid body is called its property to spontaneously restore its original shape and size after the termination of the external force.

plasticity a solid body is called its property to change shape or size under the action of external forces without collapsing; moreover, after the termination of the force, the body cannot spontaneously restore its size and shape, and some residual deformation remains in the body, called plastic deformation.

fragility of a solid body is called its ability to collapse without the formation of noticeable residual deformations.

strength a solid is the ability of a material to resist fracture under the action of stresses arising from a load or other factors.

The strength of the material is estimated by the tensile strength.

The tensile strength is the stress corresponding to the load that causes the destruction of the material sample:

where P razr is the load that causes the destruction of the sample,

F -- area,

M is the bending moment,

W is the moment of resistance.

Chemical resistance. The level of resistance of the material under the action of aggressive media - harmful gases, acids, alkalis and their solutions is called the chemical resistance of the material. The destruction of the material under the action of various reagents, moisture and gases is called corrosion. In industrial conditions, many building materials are operated under the influence of aggressive liquids and gases. In Central Asia, basically all buildings and structures are built on a saline base, which also acts aggressively on materials and leads to their destruction.

Most building materials are not resistant to acid, alkali and salt environments. Natural stone materials (limestone, granite, dolomite, etc.) are destroyed under the influence of acid. And materials from bituminous compositions, high-strength ceramic materials (plates, pipes, etc.), polymeric materials are resistant to aggressive media.

To determine the resistance of materials, a special chamber of aggressive media is used, and the samples are stored under these conditions for a certain time, then the results are compared with the reference ones.

Technological properties. The ability to change the state of the material in the process of their production is characterized by technological properties.

The technological properties of building materials include crushability, sawnability, grindability, nailability, etc.

Aesthetic properties. The sensory perception of architectural forms is associated with the aesthetic properties of building materials, which include color, shape, texture, texture, etc. These properties are important for the visual perception of the facade and the general appearance of the building.

Color - one of the properties of the objects of the material world, perceived as a conscious visual sensation. Each material has a certain color, which is perceived by sight.

White color consists of a complex of various colors. This essence was first revealed in 1666 by Isaac Newton using a special device. He noticed different spectra on a white screen, which are called Newton's spectra. There are 7 colors in the spectrum. They are arranged in the following sequence: red, orange, yellow, green, blue, indigo and violet.

The color of building materials is divided into achromatic and chromatic. Achromatic color consists of black, white and their mixture (gray). The remaining colors of the spectrum and their mixing with black and white are chromatic. A person can distinguish 300 achromatic and about 10,000 chromatic colors. Each chromatic color has 3 properties: hue, lightness and saturation.

Color tone characterized by the wavelength of radiation in nanometers: violet - 380-430, blue - 430-470, cyan - 470-510, green - 510-560, yellow - 560-590, orange - 590-620, red - 620-760. In the boundary areas, mixed colors are perceived - yellow-orange, red-orange, etc.

Lightness - a dimensionless quantity used in lighting engineering that quantitatively characterizes the difference between the visual sensations caused by two adjacent monochrome surfaces. The lightness of a material can be understood as the relative brightness of its surface.

The degree of difference between a chromatic color and an achromatic color of the same lightness is called color saturation. Saturation characterizes the level, the strength of the expressiveness of a color tone; in the human mind, it is associated with the amount of pigment in paints.

Texture - the visible structure of the surface of the material. According to the nature of the surface of the material, two groups of textures are distinguished: embossed and smooth.

Texture - these are natural patterns on the surface of wood, natural stones, etc.

In finishing materials, texture and texture are determined by comparison with the standard.

Introduction

Ceramics (dr. Greek kEsbmpt - clay) - products from inorganic, non-metallic materials (for example, clay) and their mixtures with mineral additives, manufactured under the influence of high temperature with subsequent cooling.

In a narrow sense, the word ceramics refers to clay that has been fired. However, modern usage of the term extends its meaning to include all inorganic non-metallic materials. Ceramic materials may have a transparent or partially transparent structure, may originate from glass. The earliest pottery was used as pottery made of clay or its mixtures with other materials. At present, ceramics is used as an industrial material (machine building, instrument making, aviation industry, etc.), as a building material, as an art material, as a material widely used in medicine and science. In the 20th century, new ceramic materials were created for use in the semiconductor industry and other fields.

Today, ceramic tiles have taken their rightful place not only in the design of bathrooms and kitchens, but can already be found in the design of any room. Modern manufacturers began to produce a huge variety of ceramic tiles of different shades of colors, shapes, textures and sizes, which gives unlimited possibilities in creating a unique style.

The builders got at their disposal the most diverse in size, shape, texture and color engobed, glazed, decorative mosaic tiles for facing walls and rolls, sanitary ware, new types of tiles, profile architectural inserts, three-dimensional sculptural art ceramics, etc.

Manufacturing methods:

1) Casting - the clay mass is poured into molds and fired. This is the oldest way to make tiles, but now it is not used: the edges of the tiles are uneven, and the tiles are not the same. This method is sometimes used in individual small factories, but such production is expensive.

2) Cutting - sawing natural stone (travertine or sandstone) into tiles. An even more expensive production method, which also has a low yield of tiles.

3) Extruding - stretching and cutting clay mass using a special machine.

4) Pressing - at the moment it is the most common and technologically advanced method of manufacturing ceramic tiles. Finished products are as durable as possible, and also have high aesthetic qualities. There are two main technologies for pressing ceramic coatings: bicottura and monocottura.

In modern ceramic technology, the following methods of decorating products of various purposes, shapes and sizes are used: a) glazing, b) engobing, c) coloring with ceramic paints, d) applying pre-made decorative images to the surface, e) staining with natural mineral dyes, f) two-layer molding, g) surface texturing.

Despite its venerable age, ceramics does not lose its attractiveness today. Facing with ceramic tiles continues to be one of the most convenient and practical ways to decorate rooms. Along with the decoration of the bathroom or kitchen that is familiar to us, the trend of using ceramic tiles in the interior of residential premises - bedrooms and living rooms, - decorating public buildings with ceramics and porcelain stoneware, is becoming more and more popular.

1. Product range

Ceramic tile is a flat, as a rule, thin-walled glazed or unglazed product made from ceramic mass, used for exterior or interior wall cladding and wall panels, as well as for flooring.

Glazed ceramic cladding tiles are intended for cladding the internal surfaces of walls and partitions of medical and commercial premises, canteens and kitchens, sanitary facilities, amenity premises, etc.

For the manufacture of facing tiles, white-burning clays and kaolin, quartz sand, feldspar, pegmatite, marble and some other components are used. The production of these products is carried out according to the method of semi-dry pressing of masses prepared by the slip method. the technological process consists of the following operations: preparation of raw materials, preparation and dehydration of slip, preparation of press powder, pressing tiles, their drying, glazing and firing.

All tiles can be divided into several groups:

ceramic granite (porcelain stoneware);

· terracotta;

two-burning tiles;

single-fired tiles.

Tiles are classified according to the nature of the surface - into flat, relief-ornamented, textured; according to the type of glaze - transparent or deaf, shiny or matte, one-color or decorated with multi-color patterns; in shape - into square, rectangular and shaped; by the nature of the edges - with straight and rounded on one or several adjacent sides (with a blockage).

Currently, there are several main methods for the production of ceramic tiles:

pressing and then double firing (bicottura);

pressing and single firing (monocottura);

monoprose;

extrusion technology (cotto and clinker).

Pressing and then double firing (Bicottura) - enameled ceramic tiles are produced for indoor wall cladding. Enamel gives the ceramic tile shine and allows you to display the pattern of any design, and also protects the ceramic body of the tile from moisture penetration. The entire production cycle of this type of ceramic tiles takes place in two firing processes: the first to create the base, and the second to fix the enamel. The body of a ceramic tile (“cookie”) is obtained in this way: first, a moistened mass of red clay is pressed in special forms, then it is fired at a temperature of up to 1040 ° C.

Clinker tiles. Clinker tiles are sometimes simply called clinker, although real clinker is a facing brick, a very durable, non-absorbent refractory brick made of clay fired in a special way. Clinker belongs to the group of stone-ceramic materials, made from highly plastic clays. Since facade tiles perform the same functions as facing bricks - the exterior decoration of buildings, and are also often made in the form of bricks (to imitate brickwork), such a mixture of names is permissible.

Another name is building clinker, clinker products. In general, clinker products are clay products fired to full sintering, usually in the form of a brick. The name "clinker" comes from the Dutch "klink", which means "clear ringing", since this is the sound that should be made when real clinker slabs are tapped against each other, which makes it possible to distinguish genuine ceramic tiles from tiles made of other materials. Clinker is also called a semi-finished product in the production of cement, which is a sintered mixture of limestone and clay (or slag).

Clinker is classified as an elite, high-quality finishing material. He received this recognition for high rates of strength and durability. Clinker tiles have low porosity, high mechanical strength and resistance to abrasion and chemical agents, which makes them particularly suitable for indoor and outdoor floors, stairs, for cladding the exterior walls of buildings (plinths and facades), as well as for cladding swimming pools. Clinker tile is a fire-resistant material, therefore it is often used in the decoration of fireplaces, stoves. It is also used for paving roads, lining hydraulic structures, lining tanks in chemical industries.

Clinker is made from heterogeneous types of clay with the addition of dye oxides, fluxes and chamotte. Clinker tiles can be pressed or extruded.

Classification:

In accordance with GOST 6141-91, tiles are distinguished by the following features.

According to the shape of the tiles are divided into square, rectangular and curly.

The side faces of the tiles can be without a blockage or with a blockage.

The value of the blockage radius is not a rejection sign.

Also, products of fine building ceramics can be faience, porcelain and semi-porcelain. They differ from each other in the degree of sintering of the shard, strength, and water absorption.

The front surface of tiles and fittings can be smooth or embossed, one-color or multi-color (decorated by various methods).

Decoration of tiles can be carried out by seriography, spraying, applying glazes with different surface tension, etc.

Glaze can be shiny or matte, transparent or muted.

The symbolic designation of tiles in the technical documentation when ordering should consist of an indication of their type, color and designation of this standard.

Symbol example:

white square tiles without blockage, type 2:

Type 2 white GOST 6141-91

colored rectangular tiles with a blockage of four faces, type 33:

Type 33 colored GOST 6141-91

colored shaped corner pieces, type 38:

Type 38 colored GOST 6141-91

white curly tiles, type 50:

Type 50 white GOST 6141-91

2. Technological part

2.1 Raw materials and semi-finished products

As raw materials for the production of ceramic tiles, mixtures of various materials are used, in particular:

1. clays and kaolin, which provide the plasticity of the wet mass necessary for molding tile blanks, ensuring sufficient strength of the semi-finished product in the dried state. But with an increase in their content in the mass, air and general shrinkage increases, therefore, the number of defects in production increases.

2. quartz sand, which forms the "skeleton" of the ceramic product, that is, it performs the structural function necessary to limit and control the dimensional changes of the product that are inevitable during drying and firing;

3. carbonate materials, depending on the nature of the action, are divided into fluxes (feldspars-aluminosilicates of sodium, potassium, calcium; pegmatite; dolomite, etc.) and lean (chamotte, quartz sand, etc.), due to which, during firing the desired viscosity is achieved, which provides a vitreous and dense structure of the finished product.

In addition to the main raw materials, the production uses additional ones introduced into the mass as electrolytes - soluble glass, caustic soda, surfactants of organic origin (Sulfite-alcohol bard, etc.); bleaching materials - cobalt sulfate, etc.

Glaze is a mixture of various minerals and compounds (frits, kaolin, sand, various oxides, coloring pigments), which are applied to the surface of the product and melted. According to the sintering temperature, the glaze is divided into refractory (1100-1350 ° C) and fusible (900-1100 ° C). The fusibility of the glaze depends on its constituent materials.

Refractory glazes are applied to the product in its raw form, i. without prior melting. They include: quartz, kaolin, clay, natural carbonates of divalent metals (dolomite, marble, etc.)

Low-melting glazes are pre-fused. Materials for fusing such glazes: quartz, feldspar, borax or boric acid, strontium carbonate, magnesite, dolomite, etc.

Upon subsequent cooling, the molten mass solidifies, forming glass, which gives the top layer of the tile special properties.

During slip preparation of the mass, the clay components are dissolved in water to a colloidal state, thinning and fluxes are dispersed to particles less than 0.06 mm. The refining of the components, their mixing and homogenization of the slip mass take place in an aqueous suspension, which creates the necessary conditions for subsequent technological processes - molding, drying and firing.

Grinding and coarse grinding of clay is carried out in crushing and grinding machines for primary crushing (rollers of various designs, disintegrators, planers, runners); fine grinding and mixing of components - in ball mills. The duration of grinding clay and lean is different, therefore, first, harder lean ones are loaded with a small amount of clay (up to 7%), which are crushed for 3-5 hours to prevent separation of the suspension. Then the rest of the clay is introduced and grinding is continued for another 2--3 h.

For more efficient grinding of the charge components, it is recommended to use strong surfactants that improve its rheological characteristics. These can be mono-, di- or trialkyl phosphate esters. They are added after supplying sufficient water during wet grinding.

Improving the technology of ceramic tiles in order to improve its quality is carried out at all stages of the process of its production - the selection and calculation of ceramic masses, the processing of raw materials, the preparation of slip and its dehydration when obtaining powder, pressing, drying, firing and decorating products.

To improve the structure of the shard, it is recommended to additionally introduce porcelain production waste into the composition for producing ceramic tiles.

It is proposed to use chamotte dust as lean components, since the properties of ceramic tiles with the addition of chamotte dust correspond to the regulated indicators. High-quality facing tiles are also proposed to be obtained using waste from gravity coal enrichment. Here, a feature of the technology is the preliminary roasting of the rock to burn out carbon and activate the clay component. The cost of such a tile is 40% lower than usual. Facing glazed tiles in this case has the following characteristics: water absorption 12-17%, bending strength 12-14 MPa, average density 1.9 g/cm 3 .

For the manufacture of facing tiles, solid residues of mine water are also used; in this case, the tiles may contain iron oxide in the amount of 7-20%.

name of raw materials	Unit
Clay Veselovskaya
Sand quartz
Feldspar
Liquid glass
Fitta frosting
Pigments - dyes

2.2 Choice of production method

At the factories of building ceramics, products are produced mainly in three ways: semi-dry pressing from powders with a moisture content of 5–7% (the main method), slip casting (clay suspension in water) with a moisture content of 30–33%, and plastic molding from masses with a moisture content of 14– -twenty%.

Building ceramic products are generally obtained in the process of technological processing of clay raw materials with mineral additives, molding products, drying and firing (heat treatment) to varying degrees of sintering, depending on the purpose of the product and the quality of clay raw materials.

Flow-conveyor lines (PKL) of ceramic tile production include a set of equipment, each unit of which is an independent unit in a single technology: semi-dry pressing presses, distributing and unloading devices for pressed semi-finished products before drying and firing, a slot dryer, glazing and decorating devices, high-speed firing kilns, installations for sorting and packing products.

The raw materials for ceramic tiles are the main components (clays, kaolins), thinning components to reduce shrinkage (quartz sands, natural and obtained by enriching kaolins), fluxes to lower the sintering temperature (natural - feldspars, nephelines, perlites and artificial - glass and slags) and additives (thinners, surfactants, mechanically activating, etc.).

Ceramic tiles for interior wall cladding are obtained mainly from red fusible, less often light refractory clays by semi-dry pressing of press powders with a moisture content of 6--7%, most often using slip

2.3 Technological scheme for the production of ceramic tiles

Figure 1 shows the algorithm for the production of tiles obtained by pressing in molds and further firing. In fact, each of the production stages for each type of tile has its own characteristics, which further determine the characteristics of the resulting material.

Figure 1. Algorithm for the production of tiles obtained by pressing in molds and further firing

Obtaining certain types of ceramic tiles primarily depends on the production technology. Figure 2 shows the main stages of various technological cycles and lists the main types of ceramic tiles that they allow to obtain.

Figure 2. Technological cycles for the production of various types of ceramic tiles

2.4 Description of the technological scheme

Raw material selection

Quartz sand, clay, feldspar and carbonate materials are used as raw materials for the base of the tile. The basis of ceramic glaze is frits - alloys of salts with glass. A glaze consisting only of frits has a glossy surface and is used in a double firing. To create matte glazes, quartz, metal oxides, kaolin, and coloring pigments can be added to frits.

Preparing the mixture

There are two technologies for preparing the mixture: wet and dry.

At wet technology raw ingredients are crushed and mixed in drum crushers in the presence of water. Crushers are huge drums rotating around an axis: grinding parts (stones or balls from a sintered mixture of aluminum oxide), hitting each other, crush the raw ingredients. As a result of grinding, an aqueous suspension of raw materials (slip) is obtained.

If it is necessary to press the mixture, the water is removed by the atomization process (countercurrent spraying of the slip with heated air with immediate evaporation of the water). As a result of this process, a mixture is obtained in the form of a powder, which contains 5-6% of the moisture necessary for high-quality pressing of the product.

If it is necessary to extrude the mixture, the residual moisture content of the mixture must be higher than the specified value: in this case, it is possible to remove water from the slip using a filter press.

With dry technology, raw ingredients are crushed in hammer mills and then moistened in special machines.

Grinding of the raw material is necessary to homogenize the mixture and extremely reduce its particle size, which facilitates the next firing process of the ceramic product.

Wet grinding technology is more expensive (requires a lot of energy to remove water) but gives much better results.

Single-fired, high-porosity and porcelain stoneware (gres) ceramic tiles are made from wet-grinded mixtures, while type ceramic tiles are made from dry-mixed mixtures. Clinker tiles and double-fired tiles can be produced in both ways.

The preparation of the mixture consists of several operations that provide a homogeneous material, the desired grain size and the water content necessary for subsequent molding. At this stage of production, a powder with a water content of 4-7% for compression molding or a mass with a water content of 15-20% for extruded tiles is obtained. In any case, there are three main operations at this stage - grinding, mixing - homogenization, moisturizing.

When preparing the powder for pressing, two technologies can be used: dry grinding raw materials, followed by bringing the moisture level to the desired values ​​​​with the help of humidifiers and wet technology when the raw material is crushed in water, followed by drying of the slip by spraying. The choice of this or that technology depends on the type of mass and on the characteristics of the product itself.

molding

All modern methods of molding ceramic tiles, according to ISO standards, are divided into three groups. Group A - extrusion method (production of cotto tiles, clinker). Group B - pressing method (porcelain stoneware, monocottura, bicottura). Group C included all other methods (hand molding, glass mosaic casting).

The pressing method is the most widely used. During pressing, the powdered mixture is loaded into the molds of a hydraulic press, where it is compacted under high pressure (up to 500 kg/cm²) and acquires a certain strength. At this stage, the tile may be subjected to additional processing. So, to obtain prepolished porcelain stoneware, the surface of the tile is polished with soft brushes even before firing. With the help of molds, not only the geometric shapes and sizes of ceramic tiles are set, but also the texture of its surface.

Pressing or extrusion are two molding methods used in the production of ceramic tiles. Pressed ceramic tiles are made from a powder mixture that is compacted and molded under high pressure using a hydraulic press through molds.

Extruded ceramic tiles are made from a dough-like mass of raw materials and are formed by passing through a special extruder hole using a die-die, which provides the ceramic tile with thickness and width. Next, the product is cut along the length with special knives (thin wire).

Most ceramic tiles are produced by pressing. During pressing, a powdery mass with a moisture content of 4-7% is compressed in two directions, usually under a pressure of about 200-400 kg/cm². Under pressure, the movement and partial deformation of the granules occurs, due to which even unfired tiles have the appropriate density and strength. Other types of products (fired products, clinker) are obtained mainly by extrusion, while the initial mass contains moisture from 15 to 20%, depending on the type of product. The strip exiting the extruder is then cut into appropriate dimensions.

Drying

During the drying process, moisture is removed from the product, which was necessary for molding. Its content is reduced to 0.2%. The process is carried out in dryers with hot air drying. Before entering the kiln, the ceramic tile passes through a drying chamber where hot air is supplied and where the ceramic tile loses the remaining moisture.

Drying plays an important role, since at this stage water is removed from the product, which is necessary for molding. Drying conditions are critical to product integrity, so the process is carefully controlled to avoid warping, cracking, or other defects. In the production of ceramic tiles, hot air dryers are by far the most common. Such an installation ensures the release of moisture to the surface of the product, its further evaporation and removal. The speed of the installation (the drying process lasts several tens of minutes) is ensured by good heat transfer, efficient ventilation and relatively high air temperature at which drying is performed.

Glaze application

To date, there are several dozen ways to apply glazes to the surface of ceramic tiles. Glaze can be applied in the form of granules, pasty mass or spray suspension. The moment of application can occur in different ways: before firing, after firing and even during firing. To give the tiles a more aesthetic appearance, the glazing process can be used in conjunction with the application of various images. One of the most common methods of applying ornaments is called silk-screen printing, when drawings are applied using paints through a special mesh with holes of different sizes and frequencies. The more complex the drawing, the more grids are applied.

Glaze is a mixture of various minerals and compounds that are applied to the surface of a ceramic tile and melted. Upon subsequent cooling, the molten mass solidifies, forming glass, which gives the top layer of the tile special properties. Glaze preparation consists in dosing various materials and grinding them in water. In this case, a suspension with a water content of 40-50% is obtained, ready for use. Glaze can be applied either to the fired surface (double firing) or to the dried surface as in single firing. Various types of equipment are used to apply the glaze (cone or spinneret machines, bucket or tubular dispensers, disc sprayers, airbrushes). They are included in fully automated lines, which also include machines for applying ornaments (silk-screen printing machines). Some types of ornamentation may be applied after the glaze has been fired; in this case further heat treatment (third firing) is required.

Burning

Then the tiles are fired, which can last from 40 to 120 minutes. The kiln is a closed conveyor with a length of 50 to 80 meters. By supplying gas through pipes for every 20 cm of the furnace, a certain temperature is maintained at each point. Thus, in the process of moving through the furnace, the product is fired at a temperature of 200 to 1200°C.

The most important element of the tile firing process is the development and maintenance of a temperature curve. It is the correct construction of the temperature curve that is reflected in the most important technical indicators of the tile in the future. As soon as the batch of raw materials changes, the temperature curve must be developed anew. Therefore, it is very important for a tile manufacturer to have a permanent supplier of raw materials. And, therefore, only those manufacturers who have a long history of production are able to provide consistent quality. For each type of tile, an individual temperature regime is developed. The maximum firing temperature for different materials also differs. For double-fired tiles - about 950°C, for single-fired tiles - up to 1180°C, for porcelain stoneware - up to 1300°C. In the process of firing at high temperatures, the tile loses moisture and decreases in size (shrinks). The shrinkage value increases with the firing temperature and can vary from 0% (for double-fired tiles) to 8% (for porcelain stoneware). Those. to obtain ceramic granite with a size of 300 * 300, the size of the mold should be 324 * 324.

Single firing(monocottura), when the glaze and base are fired together, is usually used to produce glazed floor tiles. The high firing temperature results in a well-sintered, durable biscuit, and provides the glaze with significant abrasion resistance. With this method of production, it is impossible to obtain products of bright, saturated colors, since at high temperatures the coloring pigments burn out and fade. It has been observed that less bright glazed tiles are more resistant to surface abrasion.

Features of single firing, caliber

Monocottura, as well as its separate type Monoporosis, is an enameled ceramic tile designed both for wall cladding and for laying on the floor. It has a denser base made of white clay compared to bicottura, and therefore some of its types are frost-resistant.

The entire manufacturing process of monocottura takes place in one firing cycle. The prepared mixture, consisting of various light grades of clay with the addition of other natural ingredients, is moistened and mixed in special drums. Then it is dried in huge vertical silos and fed in the necessary portions onto a conveyor belt, followed by placement in a mold. There, with the help of a dispenser, there is a uniform distribution of the required amount of the mixture over the entire shape of the stamp. Modern presses used at the factory allow each tile to be pressed with a load of up to 500 kg/cm², evenly distributing the force over all surfaces.

At this stage, it is very important to note that the size of the tiles coming out from under the press is approximately 7-10% larger than the nominal size (this roughly corresponds to the moisture content in the batch after the press), that is, a tile that has a catalog size of 30x30 has yet Another size is approximately 32x32. Further, in the process of drying and final high-temperature firing, the tile narrows, as it were, proportionally decreasing in linear dimensions. It must be understood that this is precisely what explains the presence of calibers assigned to tiles - in fact, the designation of its actual size. This is due to the fact that it is impossible to provide for this decrease in the firing process with an accuracy of a millimeter, it depends on many factors. Therefore, in the future, at the final stage, the tiles are sorted according to the actual size (caliber), which in turn has small tolerances, according to ISO standards. ceramic tile equipment raw materials

After leaving the press, the tiles are sent to a special final drying chamber, and then to the area where enamel is applied to the not yet fired tiles, which, after firing, protects the body of the tile and gives the appearance conceived by the designer.

After applying the enamel, the tile is fed into a furnace up to 100 m long. Gradually heating up there to a temperature of up to 1200 ° C, and then gradually cooling down, the tile goes through the same single firing, as a result of which the base acquires exceptional hardness and the enamel is fixed on it, forming a strong single whole. The whole firing process is strictly controlled by computers at each phase of the furnace. After leaving the furnace, the tile comes to the area for flaw detection and calibration, and then visual control of the tonality. Then it is sorted into batches, packed, labeled and delivered to the warehouse of finished products.

Tests at the flaw detection section consist in the fact that each tile falls on the so-called rails located along the edges of the tile and a roller is rolled in the center, acting on the tile with a certain load. If the tile has a defect, then it does not withstand the load and breaks, automatically not falling into further tests. Enamel surface defects are checked visually, at the same time as determining the tonality of the tile.

Properties of monocottura resulting from the technology of its production

The main differences between monocottura and bicottura are as follows:

? a thicker and more durable tile base, made exclusively from light clay;

? higher density as a result of using a more powerful press, and a higher firing temperature, and as a result, the presence of frost-resistant series (water absorption< 3%);

? stronger wear-resistant enamel, most often matte.

Scope, formats

Single firing tiles are produced in the formats 15.25x15.25, 16.5x16.5, 20x20 30.5x30.5 33.3x33.3 15.25x30.5 16.5x33.3. For most series, skirting boards and steps are produced in the appropriate sizes.

In many cases, monocottura tiles are offered as floor tiles for most bicottura series, thus complementing them. It can also be offered as separate series with wall decors and recommended for use on walls and floors.

There is also a special subtype of monocottura produced in 10x10 format. Tiles of this format are intended, as a rule, for facing the "apron" in the kitchen. They have a reduced thickness (approximately 6 mm) and a large number of different decors. Since this tile is mainly used in the interior, it does not have all the advantages of monocottura, but nevertheless it is stronger than bicottura and can be used as flooring in private interiors.

Monoporosis, raw material difference, properties and scope

A separate type of single-fired tile is monoporosis. This type of tile is produced by pressing and then simultaneously firing the body of the tile and the applied glaze. In this, it is completely similar to monocottura. But due to the use of several other components in the preparation of the batch, the physical properties, and, accordingly, the scope of this tile, are significantly different, and are closer to bicottura tiles.

In the production of traditional high-density single-fired tiles (monocottura and porcelain stoneware), clays with a high content of iron oxide are used, and feldspar-based fluxes are used to speed up the sintering process and give strength. In the production of monoporosa, a fundamentally different clay is used - with a high content of carbonates. During firing, as a result of chemical processes, a rather porous white mass is formed, with high water absorption (up to 15%). The strength of such a tile is noticeably less than the strength of a conventional monocottura, so the base has a thickness of 12 mm. Naturally, such tiles can only be used indoors.

This technology makes it possible to bake large-format slabs of almost ideal dimensions, which, after additional machining of the edges, can be laid with minimal seams. In the production of bicottura, where the base itself is made from red clays, the light enamel must be thick enough so as not to lose color. In monoporosis, the white base allows you to apply a thin layer of light enamel, realizing expensive graphic and chromatic effects. Decors are made both in the traditional way - by drawing a pattern on tiles, and by cutting with water under high pressure on special equipment: in this way you can get a very beautiful prefabricated decor, using, among other things, pieces of natural stone.

The white porous base and a thin layer of enamel require special rules for working with monoporous tiles: for laying it is necessary to use a white adhesive, it is necessary to rub the seams very carefully, trying not to damage the enamel. The surface for laying large format tiles must be perfectly flat.

bicottura

Double firing (bicottura) is used to produce glazed wall tiles.

The entire production cycle of this type of tiles takes place in two firing processes: the first - to create the base, and the second - to fix the enamel.

The body of the tile, the so-called base or "cookie", is obtained by pressing a moistened mass of red or white clay in special forms, followed by firing at a temperature of up to 1040 ° C. This tile is considered quite porous, with a water absorption rate of up to 10%. The thickness of the base, as a rule, is 5-7 mm, it is inferior in strength to all other types of tiles. The above properties determine its exclusively interior use for wall cladding.

The creation of "cookies" is a separate production cycle, after which the tiles undergo control of planimetry and dimensions. If the tiles do not meet the specified parameters, they are removed from the conveyor and sent for processing. To the second phase of firing - to fix the enamel, only pre-selected high-quality tiles are allowed.

The enamel covering the double-fired tiles is either glossy or matt. It does not have high surface strength as it is not expected that this tile used for wall cladding will be subjected to mechanical and abrasive loads.

The exception is some series that are recommended by the manufacturer and as floor. Naturally, they can only be laid on the floor in the bathrooms of private apartments and in no case in public places. At the same time, bicottura enamel is sufficiently resistant to household detergents used to clean ceramics, as well as to cosmetic and hygiene products that may come into contact with the tile surface in bathrooms.

Enamel application

Enamel, painted in different colors, is applied in different ways. The main one, the so-called. roller - using the RottoColor machine - a large round drum coated with a special material. The drum, rolling, applies liquid enamel, and since the length of its circumference is much greater than the length of the tile, 3-4 tiles are processed in one revolution, and the axial displacement of this drum is also often used. All this is necessary in order to make a larger number of tiles with a non-repeating pattern, while maintaining the selected design and color of this series.

Since the process of applying enamel does not affect the geometry of the tile in any way, these parameters are no longer controlled after the end of production, but are checked only for surface defects.

Bicottura properties and scope, formats

The main formats (in centimeters) currently accepted for production are: 20x20 20x25, 25x25, 25x33.3, 25x45, 12.5x45.

Bicottura is usually made in collections consisting of several colors that are combined with each other and with a large number of decors.

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