RU2621796C1 - Raw material mixture, method of manufacturing and product of construction aerated ceramics - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: raw material mixture in the form of slip for manufacturing construction aerated ceramics includes, wt %: clay or loam 12.5-66.8, electrolyte 0.1-3.5, filler 2.1-35.4, fiber 0.02-0.72, an aqueous solution of surfactants of 0.1-2.1, water 25.1-59.0. A method for manufacturing the construction aerated ceramics from the above raw material mixture in the form of slip and a product are also provided. The group of inventions is developed in dependent claims of the invention formula.

EFFECT: production of aerated ceramic products with improved characteristics by total porosity, medium density, compressive strength, water absorption and the vapour permeability coefficient.

10 cl, 9 dwg, 8 tbl, 4 ex

Description

The invention relates to the production of building materials, in particular porous ceramics, and can be used in industrial and low-rise construction in the manufacture of porous aerated ceramics, which relates to effective (heat-insulating and structural-heat-insulating) ceramic materials for construction purposes.

State of the art

The well-known "METHOD OF PREPARING POROUS CERAMIC MATERIAL WITH HIGH RESISTANCE" according to the patent of the Russian Federation No. 2423334, (IPC С04В 38/02, published on 07/10/2011, application No. 2008137644/03 dated 03/27/2010), including the steps of: obtaining the first compositions in the form of a stable aqueous colloidal solution of silicon dioxide and alkali metal oxides; for preparing a second stable composition in the form of a suspension of inorganic and / or organic particles in an organic liquid, said second composition contains compounds which, when said second composition is mixed with said first composition, can destabilize the first composition, forming a gel, and can form an organic polymer network with a blowing agent; mixing said first composition and said second composition to form a mixture; obtaining from the above mixture a porous structure in the form of a gel, where the organic structure supports the resulting inorganic structure; curing said porous structure in the form of a gel, forming a porous ceramic material in which an organic polymer network surrounds inorganic parts. The method according to the present invention allows to obtain a porous ceramic material that contains parts of silicon dioxide, optionally aggregates of silicon dioxide and ceramic parts, which make up a separate inorganic part, which is contained in a separate organic network, which acts as a skeleton and support for the inorganic part, for ceramic particles , even if they are agglomerated, with porosity in which the organic network is achieved by polymerization and can not only surround the inorganic part, but also to be associated with it. This method involves the use of organic polymers to create a porous structure of a ceramic material, which leads to a higher cost of production. Products obtained by this method are not used in civil engineering.

The well-known "METHOD FOR PRODUCING WALL CERAMIC PRODUCTS (OPTIONS)" described in RF patent No. 2277520 (IPC С04В 33/02, С03С 11/00, С04В 38/02, published on 10.06.2006, application No. 2005107395/03 dated 16.03 .2005). The known method includes mixing ground clay with exhaust and intumescent additives, moistening, molding raw products in a plastic way, drying and firing. As an exhausting and intumescent additives, a cullet is used, ground together with a pore former, granular and hydrophobized with a particle size of 0.1 ÷ 2.0 mm Calcium or magnesium carbonates or a mixture thereof is used as a blowing agent, its amount in granules is 1 ÷ 6 wt.% Cullet, and the amount of water repellent is 1 ÷ 10 wt.% Cullet. The disadvantage of this solution is that this method does not allow to obtain heat-insulating and heat-insulating structural ceramic products.

The closest in technical essence and the achieved result is the “METHOD FOR PRODUCING FOAMED CONSTRUCTION MATERIALS” according to the RF patent for IZ No. 2517133 (IPC С04В 38/08, В28В 5/04, published on 05.27.2014, application No. 2012131262/03 of 23.07.07 .2012), which includes the preparation of a ceramic-foam mixture from clay raw materials, water, additives in the form of a foaming agent, a binder, drying, firing, molding, plasticizing additives. Foaming agent PB-2007 acts as a plasticizing additive, a cementing agent - crushed finished product or perlite sand fraction 1.25-5.00 mm. The resulting foamed mixture is placed in airborne molds, dried at a temperature of 30-35 ° C at the initial stage, 50-56 ° C at the final. Then the dried billet is freed from the mold and fired in the temperature range 800-1600 ° C. After firing, the array is cut into blocks. The disadvantages of this method are: the need to use a large amount of expensive foaming agent to obtain foam, the difficulty of uniformly mixing separately prepared foam and clay slurry.

Disclosure of invention

The problem to which the present invention is directed is to create a method for producing porous building ceramics based on local clay raw materials having the required physical, mechanical and thermophysical characteristics without the use of expensive components and complex technological operations.

The technical result of the invention is the manufacture of aerated ceramic products with a porous structure with improved characteristics of their total porosity, average density, compressive strength, water absorption and coefficient of vapor permeability.

The technical result from the use of the claimed invention is achieved in that the raw material mixture for the manufacture of building aerated ceramics, including clay raw materials and pore-forming additives, in the form of a slurry contains diluting additives of electrolytes, thinning additives of filler materials, reinforcing additives in the form of fiber, and as a pore-forming additive - an aqueous solution of surfactants in the following ratio of components, wt.%:

clay or loam 12.5 ÷ 66.8

electrolyte 0.1 ÷ 3.5

filler 2.1 ÷ 35.4

fiber 0.02 ÷ 0.72

surfactants 0.1 ÷ 2.1

water 25.1 ÷ 59.0.

In this case, an aqueous solution of surfactants contained in the slip is an aqueous solution of hydrocarbon surfactants. In this case, the electrolyte contained in the slip is, for example, sodium liquid glass, or potassium liquid glass, or soda ash, or various combinations thereof. In addition, filler materials in the form of thinning additives contained in the slip are based on, for example, fireclay, or natural sands, or sands from crushing screenings, or ground glass, or the battle of clay ceramics, or dehydrated clay, or ash, or slag, or pyrite cinders, or by-products of iron ore beneficiation, or combinations. In addition, the fiber contained in the slip is, for example, basalt fiber, or polypropylene, or chrysotile asbestos or kaolin, or combinations thereof. In a method for manufacturing building aerated ceramics, including the preparation of a slip from clay raw materials (clay component), the addition of a blowing agent, molding, drying and firing using the above mixture, thinners are added to the slip electrolytes, thinning additives (filler) are introduced, which are crushed to powder state materials with a maximum particle size of 0.63 mm, and fiber (reinforcing additive) with a fiber length of 1 ÷ 12 mm An aqueous solution of surface-active substances (surfactants) is added to the slip. Then the slip is subjected, using the rotation of the blades of the stirrers of a high-speed mixer, to intensive mixing. At the same time, it is possible to aerate and form a stable porous clay mass with a shrinkage of 0.1 ÷ 25% of the initial volume based on an aqueous solution of surfactants. Moreover, intensive mixing is carried out until a porous clay mass of constant density is obtained. Then the porous clay mass is laid in a rigid form. The inner walls of the mold are pre-lubricated with a composition that reduces the adhesion of the porous clay mass to the inner walls of the mold. Then carry out a preliminary exposure of the molded porous clay mass. In this case, the temperature regime is established from the calculation of the exclusion of deformations of the porous clay mass (raw). The preliminary exposure of the molded porous clay mass is performed until the air shrinkage rate of 10 ÷ 60% is reached, and free from the form. Then the raw material is dried to a residual moisture content of 0.1 ÷ 15%, cut into the required products with the specified geometric parameters, it is heat treated at a temperature of 850 ° ÷ 1550 ° C, depending on the size of the products and the thermal properties of the constituent components. Heat treatment is performed provided that the rise time to the firing temperature is in the range from 1 to 36 hours, and the isothermal exposure time at the maximum temperature in the range from 2 to 42 hours. Carry out the cutting of products after heat treatment. Then, the cut and processed products are cooled and finished products of porous ceramic are obtained. In this case, the slip is prepared on the basis of clay raw materials with a water-clay ratio in the range from 0.32 to 1.45. However, when laying the porous clay mass in a rigid form, vibration is allowed through the use of vibrating means, for example, vibroforms, or vibration plates, or vibration dies or vibration inserts. In addition, by-products formed during cutting of products are used as thinning additives in the clay slip composition. However, the product of building aerated ceramics contains an equal density highly porous structure obtained from the composition of the raw material mixture according to p. 1 and the method according to p. 6 3- with average density characteristics of 300 ÷ 1000 kg / m ³ , compressive strength 2.8 ÷ 30.4 MPa, water absorption 10 ÷ 40% by volume, vapor permeability coefficient 0.10 ÷ 0.28 mg / m × h × Pa.

Brief Description of the Drawings

The inventive method of manufacturing building aerated ceramics is illustrated in the following figures:

FIG. 1 - aerated ceramic raw material in the process of preliminary exposure, placed in the form;

FIG. 2 - samples of finished aerated ceramic products;

FIG. 3 - the porous structure and location of the pores of the sample of aerated ceramic products (fragment of the structure of the product in an enlarged view);

FIG. 4 - microporous structure of a sample of aerated ceramic products with the composition of the components from example 1 (A snapshot of a fragment of the structure of the product with a division value of 20 μm, made using a scanning electron microscope);

FIG. 5 - microporous structure of a sample of aerated ceramic products with the composition of the components from example 1 (A snapshot of a fragment of the structure of the product with a division value of 5 μm, made using a scanning electron microscope);

FIG. 6 - microporous structure of a sample of aerated ceramic products with the composition of the components from example 1 (A snapshot of a fragment of the structure of the product with a division value of 0.5 μm, made using a scanning electron microscope);

FIG. 7 - microporous structure of a sample of aerated ceramic products with the composition of the components from example 3 (A snapshot of a fragment of the structure of the product with a division value of 20 μm, made using a scanning electron microscope);

FIG. 8 is a microporous structure of a sample of aerated ceramic products with the composition of the components from example 1 (A snapshot of a fragment of the structure of the product with the spectra indicated using a scanning electron microscope);

FIG. 9 is a microporous structure of a sample of an aerated ceramic product with the composition of the components from example 3 (A snapshot of a fragment of the structure of the product with the spectra indicated using a scanning electron microscope).

The implementation of the invention

The claimed invention is as follows.

The raw material mixture (slip) for the manufacture of building aerated ceramics includes clay raw materials and blowing agent additives, contains diluting electrolyte additives, thinning filler additives, fiber reinforcing additives, and an aqueous solution of hydrocarbon surfactants as a blowing agent.

For the manufacture of building aerated ceramics, a method is carried out that is based on the principle of aeration (forced involvement of air bubbles) of a clay-based suspension with a content of clay particles of more than 30%, water, exhaust and thinning additives, followed by the addition of pore-forming additives. Dried (humidity not more than 5%) clay rock is crushed to a powder state. In this case, the pre-dried (humidity not more than 7%) filler is crushed to a particle size of not more than 0.63. The particle size of the filler depends on the average density of the finished aeroceramic products, i.e. with increasing average density, the maximum particle size of the filler increases.

A slip is prepared from clay raw materials, filler, thinning additives and water. The water-clay ratio of the slip is in the range from 0.32 to 1.45. Clay rocks with a clay particle content of at least 30% are used as clay raw materials. Water is used as a part of the slip (temperature is 4 ÷ 80 ° С), satisfying the requirements of GOST 7473. Regenerative additives are used as a filler in the composition of the slip. The depleting additives are crushed to a particle size of not more than 0.63 mm materials based on chamotte, natural sands, sand from crushing screenings, ground glass, clay ceramics, dehydrated clay, thermal power plant ash, slag, pyrite cinders, by-products of iron ore beneficiation , and combinations thereof. Also, a reinforcing additive, basalt fiber, polypropylene, chrysotile asbestos or kaolin fiber and their combinations, with a fiber length of not more than 12 mm in an amount of 0.2 ÷ 2.9 kg / m ^3, are additionally introduced into the slip. Moreover, as an electrolyte, thinning additives are used, including sodium liquid glass, liquid potassium glass or soda ash, as well as their various combinations, amounting to 0.1 ÷ 10 wt.% Slip.

Clay slip is obtained by mixing prepared components in certain proportions: clay rock (12.8 ÷ 66.8 wt.%), Filler (2.1 ÷ 35.4 wt.%), Electrolyte (0.1 ÷ 3.5 wt. .%), water (25.1 ÷ 59.0 wt.%). A pore former in the amount of 0.1 ÷ 2.1 wt.% Of all components of the clay slip is added to the clay slurry, followed by their joint mixing to obtain a porous clay mass. Synthetic surface-active substances (surfactants), for example, PB-Formula 2012, act as a blowing agent, and other substances can also be used that make it possible to obtain stable technical foam on their basis with shrinkage from the initial volume of no more than 15%, in an amount of 0, 2 ÷ 15.5 wt.% Water introduced into the clay slip. Options for aerated ceramic compositions are presented in table 1.

Then, the resulting clay slurry is subjected to intensive mixing using a high-speed mixer (paddle, turbine, milling, propeller, frame, anchor, conical, etc.) with a blade speed in the range of 300-3200 rpm until a porous clay mass of constant density is obtained .

Then, the prepared porous clay mass (suspension) is placed in side molds, the inner surfaces of which are pre-lubricated with a special composition that reduces the adhesion of the laid porous clay mass to the inner walls of the mold. Next, there is a preliminary exposure of the molded porous clay mass to the moment of completion of the main shrinkage deformations in it and reaching an air shrinkage index of more than 40% of the molded porous clay mass (raw). The temperature regime of preliminary exposure is set based on the calculation of the absence of any deformations of the raw material. After preliminary exposure, the raw material is freed from the form and dried to a residual moisture content of not more than 15% by weight.

Then, before heat treatment, the raw material is cut into the necessary products with predetermined geometric parameters. Cutting can be carried out after heat treatment of raw. The by-products resulting from the cutting of products are reused in the preparation of clay slip.

This is followed by heat treatment of cut porous clay products at a temperature of 850-1550 ° C, the mode of which is established taking into account the dimensions of the products and the thermal properties of the components (the rise time to the firing temperature is in the range from 1 to 36 hours, the time of isothermal exposure at maximum temperature is in the range from 2 to 42 hours).

After cooling, the finished fired aerated ceramic products are placed in shipping pallets, sent to the finished goods warehouse or to the consumer.

From the compositions shown in table 1, make products of porous building aerated ceramics. Physico-mechanical and thermophysical characteristics of finished aerated ceramic products, depending on their average density, made from the compositions indicated in table 1, are presented in table 2.

The following are examples of the manufacture of aerated ceramic products used in the method according to the present invention.

Example 1. The preparation of the slip is carried out on the basis of clay Borovichsko-Lyubytinskoye field, the chemical composition of which is shown in table 3.

Aerated ceramic composition is represented by the following ratio of the components of the mixture, wt.%:

1. Clay Borovichsky-Lyubytinsky - 49.36;

2. Finely ground battle of ceramic bricks - 16.46;

3. Sodium water glass - 0.56;

4. Frother “PB-Formula 2012” - 0.71;

5. Water - 32.91.

Example 2. Aerated ceramic mixture consists of the following components, wt.%:

1. Clay Borovichsky-Lyubytinsky - 51.67;

2. The blowing agent "PB - Formula 2012" - 0.64;

3. Water - 47.69.

Example 3. The slip is prepared on the basis of Cambrian clay of the Chkalovsky field, data on its chemical composition are presented in table 4.

Aerated ceramic composition has the following ratio of components of the mixture, wt.%:

1. Cambrian clay - 43.76;

2. Dehydrated Cambrian clay - 11.22;

3. Basalt fiber - 0.36;

4. Sodium water glass - 0.49;

5. Frother “PB - Formula 2012” - 0.63;

6. Water - 43.54.

Example 4. The clay component of the slip is represented by brick loams of the Second Shaberdinskoye field, the chemical composition of which is presented in table 5.

The raw material composition is represented by the following components, wt.%:

1. Loam Scaberdinsky - 52.62;

2. Sodium water glass - 0.66;

3. Calcined technical soda - 0.12;

4. Frother “PB - Formula 2012” - 0.75;

5. Water - 45.87.

Next, each of the compositions specified in examples 1 ÷ 4 is mixed using propeller mixers with a rotation speed of 2700 rpm for 5 minutes until the completion of aeration of clay slip. Then the porous mixture is placed in the form with dimensions of 280 × 134 × 73 mm (Fig. 1). After preliminary exposure, stripping and drying, the products were fired: within 2 hours - rise to a temperature of 950 ° C, within 5 hours - isothermal exposure, natural cooling. The characteristics of the initial slips, raw materials and finished aerated ceramic products are summarized in Table 6. The finished aerated ceramic samples and the structure of the mutual arrangement of pores in the material are shown in FIG. 2 and 3, respectively.

Pictures of the microporous structure of aerated ceramic samples from the raw mix of example 1 (Fig. 4-6) and example 3 (Fig. 7) were taken using a TescanVEGA 3 SBH scanning electron microscope. Elemental quantitative analysis of samples obtained on the basis of the compositions of examples 1 and 3 are presented in tables 7 and 8, respectively. A selection of spectra for analysis is shown in FIG. 8 and 9.

Thus, the proposed method allows to manufacture aerated ceramic products with a porous structure with improved characteristics of their total porosity, average density, compressive strength, water absorption and vapor permeability coefficient.

At the same time, obtaining porous building aerated ceramics with the required structural and thermal insulation characteristics can be carried out on the basis of local clay raw materials without the use of expensive components and complex technological operations.

The claimed technical solution can be used in the production of structural elements and structural heat-insulating elements of buildings and structures; ventilation ducts and shafts, decorative products; aggregates for lightweight concrete, etc., as well as in many areas of construction.

Claims (11)

1. The raw material mixture for the manufacture of building aerated ceramics, including clay raw materials and additives pore-forming, characterized in that the raw material mixture in the form of a slurry contains diluting additives of electrolytes, thinning additives of filler materials, reinforcing additives in the form of fiber, and as an additive pore-forming - an aqueous solution surfactants in the following ratio of components, wt.%: clay or loam 12.5 ÷ 66.8 electrolyte 0.1 ÷ 3.5 filler 2.1 ÷ 35.4 fiber 0.02 ÷ 0.72 surfactants 0.1 ÷ 2.1 water 25.1 ÷ 59.0 2. The raw material mixture according to claim 1, characterized in that the aqueous solution of surfactants contained in the slip is an aqueous solution of hydrocarbon surfactants. 3. The raw material mixture according to claim 1, characterized in that the electrolyte contained in the slip is, for example, sodium liquid glass, or liquid potassium glass, or soda ash, or various combinations thereof. 4. The raw material mixture according to claim 1, characterized in that the filler in the form of thinning additives contained in the slip are materials based on, for example, chamotte, or natural sands, or sands from crushing screenings, or ground glass, or clay ceramics or dehydrated clay, or ash, or slag, or pyrite cinder, or by-products of iron ore beneficiation, or combinations thereof. 5. The raw material mixture according to claim 1, characterized in that the fiber contained in the slip is, for example, basalt fiber, or polypropylene, or chrysotile asbestos or kaolin, or combinations thereof. 6. A method of manufacturing building aerated ceramic from a slip, including the preparation of a slip from clay raw materials, the addition of a blowing agent, molding, drying and firing, characterized in that the mixture according to claim 1 is used, while diluting electrolyte additives are introduced into the slip, thinning additives are introduced, which are powdered materials with a maximum particle size of 0.63 mm and a fiber with a fiber length of 1-12 mm, add an aqueous solution of surfactants to the slip, after which the slip under They twitch, using the rotation of the blades of the stirrers of a high-speed mixer, intensive mixing with the possibility of aeration and the formation of a stable porous clay mass with an aqueous solution of surfactants with shrinkage of 0.1-25% of the initial volume, and intensive mixing is carried out until a porous clay mass is obtained constant density, then the porous clay mass is placed in a rigid form, pre-lubricating the inner walls of the form with a composition that reduces adhesion to clay mass to the inner walls of the mold, after which preliminary exposure of the molded porous clay mass is carried out, setting the temperature regime for calculating the exclusion of deformations of the porous clay mass in the form of raw material, until the air shrinkage reaches 10-60%, and free from the form, then raw dried to a residual moisture content of 0.1-15%, cut into the required products with specified geometric parameters, carry out heat treatment at a temperature of 850-1550 ° C, depending on size products and thermal properties of the constituent components, provided that the rise time to the firing temperature is in the range from 1 to 36 hours, and the isothermal exposure time at the maximum temperature is from 2 to 42 hours, the products are cut after heat treatment, and then cooled, getting finished porous products of building aerated ceramics. 7. The method according to claim 6, characterized in that the slip is prepared on the basis of clay raw materials with a water-clay ratio in the range from 0.32 to 1.45. 8. The method according to claim 6, characterized in that when laying the porous clay mass in a rigid form, vibration is allowed through the use of vibrating means, for example vibroforms, or vibration plates, or vibration dies, or vibration inserts. 9. The method according to claim 6, characterized in that the by-products formed during the cutting of products are used as thinning additives in the clay slip composition. 10. An aerated ceramic building product containing a highly porous structure of equal density obtained from the composition of the raw material mixture according to claim 6 with average density characteristics of 300-1000 kg / m ³ , compressive strength 2.8-30.4 MPa, water absorption 10 -40% by volume, vapor permeability coefficient of 0.10-0.28 mg / m × h × Pa.

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