Method of manufacture of wall ceramic articles

FIELD: wall and facing ceramics; manufacture of heat-insulating and decorative materials: tiles, blocks, wall panels.

SUBSTANCE: proposed method includes grinding of clay component, introduction of foam glass grits at size of grains of 0.1-5.0 mm preliminarily treated with water-repellent agent till obtaining of smooth surface, moistening and plasticizing, molding blanks by semi-dry method, drying and burning. Molding mass contains components at the following ratio, mass-%: water-repellent foam glass grits, 5-70; the remainder being clay component. Amount of water-repellent agent ranges from 0.1 to 10% of mass of grits. Molding of blanks by semi-dry molding method is performed at specific pressure of 4 Mpa. Waterproofed grits may be of egg-shaped or spherical form.

EFFECT: reduced heat conductivity and density of wall ceramic panels at retained strength.

2 cl, 3 tbl, 2 ex

The invention relates to a wall and facing ceramics and can be used in the manufacture of insulation and decorative materials - tiles, bricks, blocks, wall panels and other

A known method of manufacturing ceramic products, including grinding the clay slate and stcloader.exe component, the introduction of lime, mixing, moistening the mixture of 5-10%solution of alkali, forming billets at specific pressure of 15-20 MPa, drying them to a moisture content of less than 1% and subsequent annealing at 750-800°and the shutter speed when it 1-3 hours [1].

The disadvantages of the method are: high thermal conductivity (0,68...to 0.72 W/m·K), which leads to increased consumption of building materials in construction; high density (1520...1580 kg/m³), which requires an increase in the cost of materials at the production stage and, as a consequence, weight mass wall constructions that impair the technological and performance characteristics.

Closest to the proposed solution is a method of manufacturing ceramic wall, which consists in grinding the dry clay raw materials before passing through a sieve of 1 mm, the dosage of it, adding grist foam with a grain size of 0.1-2.5 mm in a ratio by dry weight 5-60 wt.%; mix dry ingredients moisturize 5% aqueous Rast is a PR sulphite yeast brew (RRT) to a moisture content of 10%, stirring until smooth. The mixture is formed using dry pressing under a pressure of 10 MPa. The product is dried to a residual moisture content of 0.5...2%, and then calcined at a temperature of 900...950°With isothermal exposure 2 h [2].

The disadvantages of the prototype are: high thermal conductivity and high density of the obtained ceramic wall.

The proposed solution aims to reduce thermal conductivity and the decrease of the density of ceramic wall while maintaining their strength.

The technical result is achieved in that in the method of manufacturing ceramic wall including grinding the clay component, the introduction of grain foam, moisturizing and plasticization of the molding material, the molding blanks by semidry pressing, drying and firing, according to the proposed solution plasticization of the molding material is performed by the introduction of a specified grain foam with a grain size of 0.1-5.0 mm, pre-treated with water repellent to acquire its smooth surface in the following ratio, wt.%:

when this number is the number of water-repellent is 1...10% of the mass of grain, and forming workpieces by semidry pressing is carried out at a pressure of 4 MPa.

Smooth water repellent surface grain foam may have a spherical or ovoid shape.

Comparison of the proposed method with the prototype allowed us to establish that the proposed solution is the introduction of pre-treated water repellent grain foam glass having a grain size of 0.1-5.0 mm and a smooth surface, the number of water-repellent is 0.1...10.0% of the mass of grain. The proposed grist allows you to simultaneously plastifitsirovanie mixture, and reduce the amount of compaction pressure up to 4 MPa. Thus the proposed solution has the criterion of "novelty".

The study of other technical solutions proposed by the authors gidrofobizirovannogo grain foam is not revealed, which allows to make a conclusion on the conformity of the proposed solutions to the criterion of "inventive step".

Characteristic components of the mass:

1. As the clay component was used:

(a) refractory clay Lokoshchenko field. THE 21-4434-84. The resistance 1430 1570...°C. Plasticity 9-12. Color after firing red. The chemical composition of the clay Lokoshchenko fields shown in table 1.

b) fusible clay (loam) of the Tula region. Oneup most 1200 1230...° C. Plasticity 17. Color after firing red light. The chemical composition of loam Tula region is presented in table 1.

2. The glass on THE 5914-003-02066339-98 "Materials and building insulation products made in the Baltic state technical University (Belgorod). The original glass density 150...200 kg/m³was crushed in a jaw crusher and sieved through a sieve with the hole diameter 5 mm sieve Residue was crushed and again optionally sieved on a sieve with the hole diameter 5 mm For removal of particulate fractions of crushed foam glass, passed through a sieve of 5 mm, was placed on a sieve with a mesh size of 0.1 mm and vibrated to stop the spillage of dust. Thus, in the inventive composition of the raw mix used pieces of foam glass in the range of 0.1 to 5 mm and a bulk density of 350 kg/m³. For cooking grains, you can use the trim and the battle of blocks of foamed glass. The chemical composition of the foam are shown in table 1.

3. As the water-repellent surface grain foam used paraffin oil brand P-2 (GOST 23683-89) in the molten state. The thickness of the paraffin layer on the grain surface of the foam depends on the viscosity of the paraffin melt. The viscosity of the paraffin melt to a large extent depends on the temperature. Thus, by changing the temperature of the paraffin melt, it is possible to adjust the thickness of the hydrophobic plank the particles of foam in order to obtain the most rolled flat surface of the granules, allowing to form spherical and rounded pores in the mass of the finished product. When using fine grain foam with minimal surface irregularities can be applied very thin film with a low consumption of water-repellent (mix 3), and the molten wax is diluted with an organic solvent - xylene (TU 6-09-2438-77) in a 1:1 ratio. As the organic solvent can also be used kerosene, gasoline, acetone, ethyl alcohol, etc. that evaporates give a hydrophobic film strength, allowing the use of mechanical mixers and forming mud wall and cladding products. As a result of such dilution receive low-viscosity solutions, allowing you to apply a very thin film of water-repellent on the surface of the grains of foam glass. Nibs made of macroporous the source of the foam glass, requires smoothing of the surface layer increased consumption of water-repellent (mixture 4).

As the water-repellent surface grain foam you can use any organic compounds that can be applied to the grain surface of the foam glass, giving it hydrophobic properties, such as silicone fluids, synthetic fatty acids, etc. Control the thickness of the hydrophobic film on the grains of foamed glass can proizvoditelno, exploring slice gidrofobizirovannogo particles under a microscope, or by increasing the size of the treated water repellent particles compared to its original value using calipers.

Surface grain foam glass water repellent is filling disqualified to sit grains of foam glass in the range of 0.1...5 mm into the tank with a melt or solution of water-repellent, stirring the mass for 5...10 minutes and removing the liquid phase through the mesh wall with a cell size of slightly less than 0.1 mm After cooling or drying to constant weight, the resulting material is ready to process the application.

Analyzing the results of physical-mechanical tests of a series of experimental samples, we can conclude that the most preferred form of grain foam after the hydrophobization - spherical and ovoid, which is achieved by selecting the viscosity of the treatment solution.

Method of manufacturing ceramic wall is as follows.

Known pulverized clay raw material to the dispersion of particles less than 1 mm, dispense, add gidrofobizirovannogo grains of foam glass in the ratio by dry weight specified in table 2. Mix dry ingredients moisturize with water to a moisture content of 4...8% according to [3, s], mix until homogeneous is Oceania. The mixture is formed using dry pressing under pressure 4...7 MPa. The reduction of pressure during the moulding of products in comparison with the methods described in [1-3], contributes to a noticeable improvement in workability of the raw material mixtures, prepared by the present method, due to better slip between the particles of clay and gidrofobizirovannogo the surface of the foam glass. Vodostojot commodity charges can be reduced to 4%, which also facilitates the drying of raw material shrinkage during drying is virtually absent. The product is dried to a residual moisture content of 0.5...2%, similar to [2], and then calcined at a temperature of 900...950° [2; 3, s-128].

Example 1. Weighed pre-dried, crushed and sieved through a sieve with openings of 1 mm Lukacinsky clay in the amount of 5.8 kg (58%, see table 2), this clay was added 4.2 kg of crushed foam glass (consisting of 40% grain foam and 2% of water-repellent), sifted through a sieve with a size of the cell diameter of 5 mm and retained on the sieve 0.1 mm and treated with 0.2 kg of molten paraffin (table 2, mixture 1). These two components were mixed in a laboratory screw mixer and simultaneously mixing poured water in an amount of 0.4 kg of the resulting mass was molded using dry pressing in a hydraulic press under a pressure of 4 MPa. The obtained raw strength allows TRANS the clutch and drying of samples without any restrictions. Molded samples in the form of tiles with size 192×142×9 mm cylinder diameter and height of 50 mm (the latter samples were intended to determine the ultimate strength in compression) was dried to a residual moisture content of 2%, and then annealed at a maximum temperature of 950°aged 2 hours, i.e. simulated production conditions for obtaining a building of red brick [3, s.89-128]. After cooling, the specimens were tested for strength, determined by the density and thermal conductivity. Was determined visually decorative properties of the samples. The results are given in table 3 (mixture 1).

Example 2. Weighed pre-dried, crushed and sieved through a sieve with 1 mm aperture loam Tula in the amount of 5.8 kg (table 2, mixture 2), this loam was added 4.2 kg of crushed foam glass, sifted through a sieve with a size of the cell diameter of 5 mm and retained on the sieve 0.1 mm and treated with 0.2 kg of molten paraffin. These two components were mixed in a laboratory screw mixer and simultaneously mixing poured water in an amount of 0.4 kg Mass was molded using dry pressing in a hydraulic press under a specific pressure of 6 MPa. Molded samples in the form of tiles with size 192×142×9 mm cylinder diameter and height of 50 mm, dried

to a residual moisture content of 2%, and then annealed at a maximum temperature of 900°aged 2 hours. After cooling, the specimens were tested for strength, determined the density and thermal conductivity. Visually determined the decorative properties of the samples. Rez is ltati tests are given in table 3 (mix 2).

The ratio of raw materials and the firing temperature of the ceramic mass in examples 1 and 2 (table 2, mix 1-2) selected from the experimental sample series as the most rational microstructure and physical-mechanical properties of the obtained ceramic wall.

Similarly prepare the rest of the mixture according to the claimed method for producing a ceramic material and, accordingly, on the basis of samples of wall materials and wall tiles, including a spaceship values of grain size gidrofobizirovannogo grain foam glass (compositions 5-6), and the known composition of the paste 7 (prototype). The results of the properties are listed in table 3. The experiments were carried out in laboratory conditions BSTU.

Data analysis table 3 test results of sample properties of wall and facing ceramics manufactured by the present method, shows the following.

1. All grades 1-4 meet the requirements of GOST 7025-91 "Bricks and stones, ceramic and silicate".

2. The introduction of the mass gidrofobizirovannogo grain foam allows you to get durable, high-quality ceramic materials.

3. As the number of grains of foam glass up to 5 wt.% and deposited on the surface of water-repellent up to 0.05 wt.% in relation to the weight of the molding mixture (0.1% in relation to the weight of grain) of coefficients is ient thermal conductivity and density compared with the prototype reduced, this significantly - almost 2-fold increased strength samples (mixture 3). Further reducing the number gidrofobizirovannogo grain foam glass is impractical because the resulting ceramic materials slightly surpass comprehensive qualitative characteristics of the prototype.

4. When the number gidrofobizirovannogo grain foam to 70 wt.% (63,64 wt.% semolina and 6,36 wt.% the water-repellent) density and coefficient of thermal conductivity is reduced, however, and their strength is reduced by increasing the friability of the structural skeleton (mix 4), the further increase of the amount of grain in bulk is impractical because there is a drop of strength derived ceramic materials due to the small fraction of the clay component in the charge and the emergence of viplavam.

5. Use gidrofobizirovannogo grain foam glass with a particle size less than 0.1 mm is not possible to obtain ceramic products of low density and low thermal conductivity, because dust particles foam does not contribute to the creation of a porous structure of ceramic materials (mixture 5).

6. The use of crumb foam glass with a particle size greater than 5 mm are also impractical because the resulting system of large pores contributes to the emergence of convective heat transfer, which reduces insulation'hara the indices of the obtained materials (mixture 6), when firing a mass of serious structural defects, friability, wyplay, which reduce the strength characteristics, worsen the appearance of products.

The inventive method of manufacturing ceramic wall in comparison with the prototype has the following advantages:

1) heat-insulating properties are improved by 25...30%;

2) the density while maintaining the required physical and mechanical characteristics is reduced by 20...30%;

3) making gidrofobizirovannogo grain foam we carry out the plasticization of the mixture, discarding the use of sulphite-yeast brew, thus forming properties of the blends are improved so that you can reduce the pressure up to 4 MPa and humidity blanks with 10% (prototype) to 3...7% (table 3, a mixture of 1-4);

4) obtained by firing the ceramic material has a uniform closed-porous structure and has a good decorative properties.

The physico-chemical nature of the technical solution for achieving the task consists in the following: gidrofobizirovannym globules of foam glass due to its low bulk density (340 360...kg/m³and, occupying a volume of raw mass, forms a porous structure raw, and by hydrophobization of the surface of the grains and the presence of a layer of water-repellent treated pellet is smooth and ideal the capacity option - spherical and egg-shaped) surface within which is enclosed fusible porous glass mass. For this reason, the structure of the raw has all the prerequisites in the firing process for forming spherical vitrified closed pores.

The presence of uniformly distributed, predominantly spherical and egg-shaped, vitrified closed pores in the whole volume of ceramic products can significantly increase the ability to withstand mechanical loads compared to ceramics [2], where the form then has angular edges and uneven surfaces, contributing to the creation of centres of tension in the presence of mechanical stress. It is known that the spherical surface then you can greatly reduce the density, and hence the conductivity derived walling and cladding products derived from the claimed compositions of ceramic masses, while maintaining the strength characteristics.

Hydrophobizated particles of foamed glass having low adhesion to the clay component and between them, make the raw mass of the charge pattern and udoboukladyvaemost, i.e. plastificator it so that when the molding requires much less effort (4...7 MPa). Gidrofobizirovannym grit foam at the same time is Autodialer charge much Bo the greater degree, than the grains in the charge of the prototype [2], reducing its vodostojot from 10 a.m. to 4%, which leads to the elimination of shrinkage phenomena during drying of raw, excluding the formation of shrinkage cracks.

RRT (see 2)as plasticizing the raw weight of the additive and increasing its mobility, the molded products contributes to a more complete filling of surface roughness grain foam, which leads to an increase of the density, thermal conductivity and the decrease in strength of the finished wall and cladding materials. For these three reasons, the use of aqueous solution of the RRT as a plasticizer of the ceramic material becomes impractical in the claimed method it is excluded.

Upon firing, the organic repellent fade with exothermic effect, contributing to the accelerated preparation of raw sugar for baking. It is known that when reaching 780...850°With the glass goes into the liquid phase, actively interacting with the particles of the clay across the surface of the pores. By this time the clay component of the mass creates a strong structural skeleton of the material, which prevents thermal shrinkage of the product. During isothermal holding at the maximum temperature for 1...3 hours ready steklovata leads to faster reactions mulitauaopele with subsequent crystallization of mullite in the pore walls and what armirovanie (proved microscopic and petrographic studies). The authors found that reinforcement and high density vitrified walls of the pores prevents the cracking of the obtained glass-ceramic materials, this explains their high strength and low water absorption (8...10%) even with a reduced density compared to the prototype. Ensuring uniform closed porosity of the spherical shape in the ceramic material also leads to a lower thermal conductivity almost 25...30% compared to the prototype.

The reduction of the contacting surfaces of the components of the ceramic material in the firing process and the creation of a system of ordered spherical pore mitigates the appearance of viplavam when firing obtained by the present method of ceramic masses and increase the size of the used gidrofobizirovannogo grains up to 5 mm, which allows to further reduce the density and increase the insulating properties of the wall and cladding products.

Obtained by the present method walling and cladding products are of good decorative figures have the appearance of natural tuff materials and products made from white burning clay - limestone. To achieve a more decorative effect permitted the introduction of additional pigments in the composition of the raw ceramic material. The use claimed the th method of manufacturing ceramic wall in the building materials industry will also solve the problem of waste production of foam glass.

Sources of information

1. RF patent №2036880, CL 6 04 33/00, 28/20, 1995.

2. RF patent №2231505, CL 7, 04 At 33/00, 03 11/00, 2004.

3. Frost I.I. Technology of building ceramics. Kiev: "Vyscha SHKOLA, 1980. - S.89-128.

1. Method of manufacturing ceramic wall including grinding the clay component, the introduction of grain foam, moisturizing and plasticization of the molding material, the molding blanks by semidry pressing, drying and firing, characterized in that the plasticization of the molding material is performed by the introduction of a specified grain foam with a grain size of 0.1-5.0 mm, pre-treated with water repellent to acquire its smooth surface in the following ratio, wt.%:

the number of water-repellent is 1-10% by weight of grain, and forming workpieces by semidry pressing is carried out at a pressure of 4 MPa.

2. The method according to claim 1, characterized in that the smooth water repellent surface grain foam glass has a spherical or ovoid shape.