RU2349563C2 - Manufacturing method of foam-ceramic products - Google Patents

Abstract

FIELD: construction industry.

SUBSTANCE: invention refers to building material industry, and namely to manufacturing of foam-ceramic materials. Manufacturing method of foam-ceramic products involves mixing of clay, filler, combustible, stabilising and fluxing additives, liquid glass, plastifier, portland cement, water and foaming agent, moulding, drying and burning of products. Saw dust with particle size of 0.25-0.315 mm is used as combustible additive, ceramic brickbats - as filler, powdered glass and aluminium etching waste with density of 1.05-1.3 g/cm³ - as fluxing additive, and foam prepared separately - as foaming agent. At that before component mixing there shall be crushed clay, ceramic brickbats and powdered glass to particle size of 70-100 microns. Mixture component ratio is as follows, wt %: clay - 36.30-41.90, ceramic brickbats - 7.72-9.10, aluminium etching waste - 3.20-5.30, powdered glass - 6.30-9.70, liquid glass -1.25-1.29, saw dust - 1.90-4.40, plastifier - 0.10-0.20, portland cement - 4.25-4.80, foam - 0.30-0.40, and water - 30.10-32.60.

EFFECT: improving strength, and reducing thermal conductivity.

3 cl, 8 tbl

Description

The invention relates to the construction materials industry, mainly to obtain ceramic foam materials for the device of effective building envelopes of residential and public buildings.

A known method of preparing foam clay, including the preparation of a slip, molding and 28 day exposure (Chernykh V., Mashtakov A., Galagan K., Shestakova E. Building products using clay raw materials // Building materials. 2003. No. 12. p.46- 47), and the slip consists, wt.%:

clay 43.8;

cement 21.9;

lime 1.31;

hydrophobic additive 0.15;

hardening accelerator 0.31;

foam 1.22;

water 31.28 (rest).

The disadvantage of this method is the relatively low strength, high density and low coefficient of water resistance of the resulting products and low frost resistance.

Closest to the invention is a method of producing ceramic foam, which involves mixing clay, aggregate, fiber, water and a blowing agent, forming products, drying and firing. Basalt fiber is used as fiber, ground glass or burnt clay and foam are used as filler. Additionally, plasticizer, water glass, phosphoric acid are introduced (application No. 2004111833/03, publication date 05/10/2005, patent start date 04/20/2004, author Galagan K.V. et al.). The ratio of the components of the mixture is, wt.%:

clay 46-56;

placeholder 7.8-12.8;

water glass 0.07-0.77;

fiber 0.39-0.43;

plasticizer 0.13-0.23;

phosphoric acid 0.13-0.38;

foam 2.6-3.8;

water is the rest.

The disadvantage of this method is the relatively low strength of ceramic products and increased thermal conductivity.

The invention is aimed at increasing strength, reducing thermal conductivity, expanding the raw material base of the initial components of ceramic foam products and improving environmental safety as a result of the disposal of industrial waste

The result is achieved in that in the method for producing ceramic foam products, comprising co-mixing finely ground clay, aggregate, burn-out, stabilizing and fluxing additives, water glass, plasticizer, water and a blowing agent, molding, drying and firing products according to the invention, as a burn-out additive using sawdust fractions 0,25-0,315 mm, as a filler bout ceramic bricks, fluxing agent as ground glass and aluminum etching waste density 1.05-1.3 g / cm ^3, e ohm clay, brick and ceramic battle ground glass components are ground before mixing to a particle size of 70-100 microns, and as a blowing agent is separately prepared foam additionally introduced Portland cement; drying the molded samples is carried out at 40-60 ° C, and firing at a temperature of 980-1050 ° C, while the ratio of the components of the mixture, wt.%:

clay 36.30-41.90;

ground battle of ceramic bricks 7.72-9.10;

sawdust 1.90-4.40;

Portland cement 4.25-4.80;

aluminum etching waste 3.20-5.30;

ground glass 6.30-9.70;

water glass 1.25-1.29;

plasticizer 0.10-0.20;

foam 0.30-0.40;

water 30.10-32.60.

The result is achieved by the fact that the products are molded in collapsible metal forms laid out by paper, which protects them after stripping from mechanical damage during transport to the furnace, before the products are fired, the paper is removed and reused.

The result is also achieved by the fact that the firing is carried out at an optimum temperature of 1030 ° C.

The following ingredients were used to obtain ceramic foam products: clay of the Saray-Chekurchinsky deposit, ground battle of ceramic brick - waste from the production of the Arsk brick factory, aluminum etching waste, the compositions of which are given in table 1.

Table 1 No. Content, wt.% H ₂ O SiO ₂ TiO ₂ Fe ₂ About ₃ MnO CaO MgO Na ₂ O P ₂ O ₃ SO ₃ ppp Al ₂ O ₃ FeO K ₂ O one 4.19 69.37 13.69 4,52 0.08 1.90 1.43 3.3 0.11 0,07 5.3 2 0.08 72.83 12.73 5.99 0.09 2.95 1.7 2.93 0.1 0.09 0.45 3 - - 38.0-40.2 1.7-1.8 - - - 44.2-46.0 - 1,0 - 2,3 - Note: 1 - clay Saray-Chekurchinskaya; 2 - battle of ceramic brick - a waste of the production of the Arsky brick factory; 3 - waste etching aluminum.

As a foaming agent used "Penostrom" according to TU 0258-001-22299560-97 or PB-2000 according to TU 2481-185-05744685-01.

Superplasticizer S-3, powder of light brown color, corresponds to TU 6-36-0204229-625. During operation does not have a harmful effect.

Aluminum etching waste is a dark yellow liquid with a density of 1.05-1.3 g / cm ³ . These multi-tonnage waste is currently not used anywhere and sent for regeneration, which requires large material costs for their neutralization. Aluminum etching waste - aluminate-salt solution in the form of monosodium aluminate Al ₂ O ₃ , in small amounts of Al (OH) ₃ and a small amount of other components. The chemical composition of alkaline components is given in table 1. The choice of these additives is justified by the presence of Na ₂ O and Al ₂ O ₃ , the presence of alkali metal oxides (in this case, Na ₂ O) in them reduces the formation temperature of the pyroplastic mass, and the presence of Al ₂ O ₃ in the system increases the strength of the crock.

Ground glass was obtained by grinding glass containers (GOST R 52022-2003) in a ball mill to a fraction of 70-100 microns.

Sodium liquid glass (GOST 13078-81) is a thick yellow or gray liquid without mechanical impurities and impurities.

As a stabilizing additive, Volsky Portland cement of grade 500 GOST 10178-85 was used.

Sawdust is a waste of wood processing plants, for example Vasilievsky - Vasilievo, Zelenodolsky district, Tatarstan, which are formed in large volumes and are currently not used anywhere. The bulk density of sawdust is 180-190 kg / m ³ , the fraction of wood sawdust used is 0.25-0.315 mm.

The water used to produce ceramic slurry and foam is in accordance with GOST 23732-79.

Ceramic mixture is prepared as follows. In the mixer, the component mixture is prepared within the limits indicated in the formula (in wt.%): Clay, ground brick, ground glass, Portland cement, water glass, aluminum etching waste, sawdust, S-3 plasticizer, water. Add foam and mix thoroughly for 0.5-1 minutes. The mixture is poured into forms coated on the inside with paper. Then dried at a temperature of 40-60 ° C for 24 hours, burned at a temperature of 980-1050 ° C for 12 hours. The temperature and duration of firing depend on the type of clay used, the amount of waste etched aluminum and ground glass. With an increase in the amount of etching waste and ground glass, the firing temperature decreases. The residual moisture of the samples after drying should be 5-7%. At lower and higher humidity, cracking occurs during firing of products and a decrease in strength.

The input of clay, the battle of ceramic bricks and ground glass, crushed to particle sizes of 70-100 microns, is justified by the fact that they, when fine grinding, interact better within the firing temperature of ceramic foam products. Table 2 shows that with a fineness of 70-100 microns, the greatest mobility of the ceramic slurry is ensured due to the fact that the most dense packing of the raw material particles is achieved at the lowest specific surface area. This helps to strengthen inter-pore walls and, ultimately, increase the strength of the product and reduce water absorption.

table 2 No. p / p The fineness of grinding battle brick and ground glass, microns Slip mobility, mm one less than 50 77 2 50-70 115 3 70-100 134 four 100-120 98

The addition of Portland cement and water glass helps to fix the structure during the drying of products, reduce shrinkage and density of foam. As can be seen from the results presented in table 3, the joint use of Portland cement with liquid glass mutually activates its action and accelerates the process of structure formation of foam, reducing its shrinkage.

Table 3 No. p / p Additive Properties of foam Density, kg / m ³ Shrink% Cracks pcs. (more than 10 mm) one Portland cement 590 eleven four 2 Liquid glass 595 14.5 6 3 Portland cement + water glass 590 9 2 four Counter. composition (no additives) 600 21.5 12

It is better to use S-3 superplasticizer as a plasticizer, which is used to increase the mobility of the slip, reduce moisture content and reduce the time required for the moisture transfer of the foam slip mass during drying of products. The results of the study of various plasticizers on the ceramic slurry mobility, presented in Table 4, confirmed that the C-3 superplasticizer contributes to the greatest increase in the ceramic slip mobility with an equal amount of mixing water for all compositions, which accelerates the process of moisture transfer during the drying of foam and reduces cracking

Table 4 No. comp. Slip composition,% (vol.) From clay W / T Spray mm Clay S-3 Soda PS Without additives one one hundred 0.3 0.6 161 2 0.3 0.6 134 3 0.3 0.6 128 four - 0.6 107

To reduce the shrinkage, increase the crack resistance of the raw material during drying, reduce the average density and thermal conductivity of the ceramic foam product, sawdust was used as a burnable additive. The introduction of wood sawdust is justified by their reinforcing effect, because Particles of wood sawdust, dispersedly distributed in the foam slurry, structurally strengthen it, reducing shrinkage and cracking. In the process of firing, sawdust burn out and form additional macroporosity, which reduces the density and thermal conductivity of ceramic foam. It was found that the greatest effect is achieved with the introduction of wood sawdust fractions of 0.25-0.315 mm, because with a smaller fraction, water demand increases sharply, and with a larger fraction, the finely porous foam slurry structure formed by the introduction of foam is destroyed.

The use of foam in the manufacture of ceramic foam products provides a cellular structure with closed pores, which improves heat-shielding properties and reduces thermal conductivity. Table 5 presents the results of a study of the influence of the type of foaming agent on the density and thermal conductivity of ceramic foam. It is seen that with the use of the PB-2000 and Penostrom foaming agents, the smallest shrinkage, average density and thermal conductivity are observed, this is due to the formation of a more uniform porosity and closed pore nature in comparison with samples prepared using other foaming agents.

Table 5 No. p / p Foaming agent The properties Note Density, kg / m ³ Thermal conductivity, W / (m · ° С) one PB 2000 520 0.106 2 Unipor 700 1.3 cracked 3 Penostrom 575 0.108 four ON 6 650 0.125

Drying is carried out to a residual moisture content of 5-7% at an optimum temperature of 40-60 ° C. The properties of the foam composition of the same composition at different drying temperatures are presented in table 6. At a higher temperature, the foam breaks and crack formation increases. Drying the foam at a temperature of less than 40 ° C slows down the process of moisture loss and fixing the structure of the foam, which increases shrinkage and cracking. At temperatures above 60 ° C, an increase in cracking and shrinkage also occurs due to the fact that at elevated temperatures the foam collapses and does not have time to fix the foam structure. Therefore, the optimum drying temperature is a temperature of 40-60 ° C, at which, as can be seen from table 6, the smallest shrinkage and cracking are observed. This is due to the fact that with uniform moisture loss, the structure of the foam has time to consolidate without destroying the foam and causing internal stresses. In the drying process after stripping, the raw material is turned upside down to change the direction of moisture loss, which allows to reduce shrinkage and maintain uniform porosity.

Table 6 No. p / p Drying temperature, ° С Properties of foam Shrink% Density, kg / m ³ Cracks pcs. (more than 10 mm) one 30-40 12 605 5 2 40-50 8.5 530 2 3 50-60 9 560 3 four 60-70 eighteen 685 9

The formation of ceramic foam products is carried out in collapsible metal forms. In this case, forms are used for molding, the bottom of the walls of which are preliminarily lined with paper, which, after stripping the foam-ceramic raw material, protects it from mechanical damage during transportation to the furnace, however, the paper is removed and reused before firing.

Ceramic foam firing is carried out at a temperature of 980-1050 ° C (optimal 1030 ° C) for 12 hours. The firing duration depends on the type of clay used, the amount of aluminum etching waste (hereinafter OTA) and ground glass. It was found that with an increase in the amount of OTA and ground glass, the firing temperature decreases. X-ray phase and differential thermal analyzes of the control samples of ceramic foam fired in the indicated temperature range showed that an increase in the strength of the shard when introducing fluxing components in the form of a mixture of OTA and cullet is associated with the formation of volostonite and monoclinic pyroxene.

The data of experiments on obtaining ceramic products are presented in tables 7 and 8.

Table 7 No. comp. The composition of the mixture, wt.% Clay Brick fight Ground glass Sawdust Aluminum etching waste Foaming agent Portland cement Liquid glass Plasticizer S-3 Water one 41.90 7.72 6.40 1.90 4.80 0.40 4,50 1.28 0.1 31.00 2 38.80 8.71 9.70 3.20 3.20 0.30 4,50 1.29 0.20 30.10 3 40.10 8.10 6.40 3.20 4.80 0.30 4.80 1.27 0.13 30.90 four 36.30 9.10 6.30 4.40 5.30 0.40 4.25 1.25 0.1 32.60 5 45.50 7.29 3.30 4.90 3.30 0.40 3.30 1.31 0 30.70 6 32.75 9.20 9.70 4.40 6.30 0.30 3.10 1.25 0.2 32.80 The composition of the prototype 7 46 Burnt clay 12.8 Basalt fiber 0.41 Phosphoric acid 0.38 3.8 0.77 0.23 35.61

It can be seen that the compressive strength of the samples obtained by the proposed method is 3.7-4.0 MPa at a density of 580-630 kg / m, the closest analogue (prototype) compressive strength is 3.5 MPa at a density 650 kg / m ³ . The thermal conductivity of the claimed compounds is 0.108-0.119 W / (m · ° C), the closest analogue is 0.14 W / (m · ° C).

The present invention can be used in almost any factory for the production of ceramic bricks for the manufacture of structurally heat-insulating foam-ceramic products, which can be used to create effective building envelopes in residential and public buildings. The invention allows to increase the strength of the ceramic foam product, reduce thermal conductivity, as well as expand the raw material base of the initial components of ceramic foam products and recycle industrial waste.

Table 8 The properties Composition Indicators one 2 3 four 5 6 Prototype The limit of compressive strength, MPa 3,7 3,7 3.8 4.0 2.1 5,4 3,5 The average density, kg / m ³ 590 580 600 630 420 870 650 Thermal conductivity, W / (m · ° С) 0,110 0.108 0.109 0.119 0,087 1,142 0.14

Claims (3)

1. A method of producing ceramic foam products, including joint mixing of finely ground clay, aggregate, burn-out, stabilizing and fluxing additives, water glass, plasticizer, water and a blowing agent, molding, drying and firing of products, characterized in that wood sawdust is used as a burn-out additive fraction 0,25-0,315 mm, as a filler - battle ground ceramic bricks, as a fluxing agent is introduced ground glass and aluminum etching waste density 1.05-1.3 g / cm ^3, wherein the clay bout ke bricks and ground glass before mixing the components are crushed to a particle size of 70-100 microns, and separately prepared foam is used as a foaming agent, Portland cement is additionally introduced, the molded products are heated during drying at 40-60 ° C, and firing at a temperature of 980 -1050 ° C, while the ratio of the components of the mixture is, wt.%:
clay 36.30-41.90 ground battle of ceramic brick 7.72-9.10 sawdust 1.90-4.40 Portland cement 4.25-4.80 aluminum pickling waste 3.20-5.30 ground glass 6.30-9.70 liquid glass 1.25-1.29 plasticizer 0.10-0.20 foam 0.30-0.40 water 30.10-32.60 2. The method according to claim 1, characterized in that the products are molded in collapsible metal forms laid out by paper, which protects them after stripping from mechanical damage during transport to the furnace, the paper is removed and reused before firing. 3. The method according to claim 1, characterized in that the firing is carried out at a temperature of 1030 ° C.