RU2605982C2 - Method of producing granular construction material - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to production of construction materials, in particular, to production of artificial porous aggregates for concrete and granular heat-insulating materials for charging of heat insulation, as well as to production of semi-finished product for production of granulated construction material. Method of producing granular construction material, which involves preparation of a silica component, preparation of a binding solution, mixing of components, granulating mixture and heat treatment, binder solution is prepared based on colloidal silica and soluble salts of alkali metals by combined wet grinding with simultaneous dissolution of sodium silicate with silica modulus of 1.0 to 4.0, sodium carbonate and/or other water-soluble compounds of alkali metals at temperature 80–110 °C, at following ratio of basic components: vitreous sodium silicate – 10–50 %, sodium carbonate – 5–40 %, water – 40–80 %, wherein mixing silica component with a binding solution is combined with addition of gas-forming agent and granulation of mixture, wherein mixing and granulation are carried out in one device – granulator with ratio of binding solution and silica component from 1:5 to 1:1.2, then raw granules are subjected to thermal treatment: drying to moisture content 1–15 % and annealing at 750–1,100 °C, wherein total content of alkaline oxides in finished material ranges from 5 to 20 wt%. Invention is developed in subclaims.

EFFECT: improved operational characteristics of material, particularly low packed density and volumetric water absorption.

6 cl, 10 ex

Description

The invention relates to the field of production of building materials, in particular the production of artificial porous aggregates for concrete and granular insulating materials for backfill insulation, as well as to the production of a semi-finished product for the production of granular building material.

A known method of producing a semi-finished product for the manufacture of building materials, including granular porous material, comprising mixing a silica-containing component, an alkaline component, which is used as sodium hydroxide, and water to obtain a suspension and drying it to obtain a semi-finished product, drying is carried out by spraying the suspension to obtain granular semi-finished product with a moisture content of not more than 9 wt.%, molding a bulk semi-finished product to obtain raw billets from it in the form of granules, calcining raw of granules, after which the raw granules are subjected to thermal expansion to obtain a porous backfill, heat-insulating or structural-heat-insulating material (RF patent No. 2397967, 2009).

The disadvantage of this method is the high humidity of the reaction suspension, spray drying of which is associated with high energy consumption for the evaporation of water and the high cost of equipment, as well as the two-stage production of raw granules based on granular semi-finished product. Also a disadvantage of this method is the high price of caustic soda, compared with soda ash and its derivatives. The disadvantage of this method is the danger of sodium hydroxide solutions that cause chemical burns to the skin and eyes.

The closest in technical essence and at the same time a prototype is a method of obtaining a building material, including in the form of granular material, including the preparation of a siliceous component and a binder solution, mixing them to obtain a homogeneous mass, its exposure at a temperature of 0-150 ° C for the formation of hydrosilicates and subsequent firing, using siliceous rock composition, wt.%: SiO ₂ 30-98, Al ₂ O ₃ up to 20, Fe ₂ O ₃ up to 8, CaO up to 25, MgO up to 8, carry out its drying, heat treatment at 250 -700 ° C for at least 0.5 hours, from grinding to a fraction of less than 5 mm, then mixing in the following ratio of components, wt.%: silica-containing component 60-98, alkali 2-40, water 0-100 by weight of dry components, and upon receipt of a granular structural-heat-insulating or heat-insulating material, the components are mixed and additionally enter 0-10 wt.% mineral pigment, then the mixture is granulated, carry out the specified exposure, drying, heat treatment at 250-650 ° C for at least 0.5 hours and burn at 660-1000 ° C for 0.2 -12 h, while in the capacity of alkali isp Sodium hydroxide or potassium hydroxide is used.

The bulk density of the obtained granular material is 200-250 kg / m ³ with a raw granule size of 5-10 mm (RF Patent No. 2333176, 2007).

With the essential features of the invention, the following set of features of the prototype coincides: "A method for producing granular building material, including preparing a siliceous component, preparing a binder solution, mixing the components, granulating the mixture and heat treatment."

The disadvantages of the prototype are:

- low heat engineering parameters of the obtained product and increased raw materials costs due to its relatively high density - 200-250 kg / m ³ ;

- a relatively high volumetric water absorption exceeding the water absorption of granular foam glass of similar density;

- the preparation of raw granules for the production of granular material includes two technological operations carried out in different apparatuses: preparing the raw material in the mixer and granulating the resulting mass, the presence of a phase for the preparation of a viscous molding mass that quickly hardens as the components interact, which makes it difficult to obtain a semi-finished product;

- the high price of caustic soda, compared with soda ash and its derivatives;

- the danger of sodium hydroxide solutions that cause chemical burns to the skin and eyes.

The problem to which the invention is directed is to: improve the operational characteristics of the material, namely, reducing the bulk density and lowering the water absorption, reducing the consumption of raw materials per unit of finished product (cubic meter), using cheaper sodium-containing raw materials than sodium hydroxide, and simplification of the process and increase productivity of equipment.

The problem is solved by using a multicomponent binder solution, which provides a greater foaming coefficient and lower open porosity of the material, in a special way to prepare a multicomponent binder solution, as well as the choice of a single-stage method for producing raw granules from a silica component powder and a binder solution, combining mixing and granulation operations.

When carrying out the invention, the following technical results can be obtained: improving the operational properties of the building material, using available raw materials in the form of siliceous rocks in its preparation, reducing the total consumption of sodium-containing components by reducing the proportion of sodium oxide, using cheaper and safer sodium-containing components in the form of vitreous silicate sodium and soda ash, simplifying the process by combining mixing and granulating operations, sn reduction of energy consumption by reducing the moisture content of the raw mix.

These technical results are achieved due to the fact that in the method for producing granular building material, including preparing a siliceous component, preparing a binder solution, mixing the components, granulating the mixture and heat treatment, the binder solution is prepared on the basis of colloidal silica and soluble alkali metal salts by co-wet grinding with the simultaneous dissolution of glassy sodium silicate, sodium carbonate and / or other water soluble alkaline metal compounds alls at a temperature of 80-110 ° C, with the following ratio of the main components: glassy sodium silicate -10-50%, sodium carbonate - 5-40%, water - 40-80%, and the mixing of the siliceous component with a binder solution is combined with the addition of a blowing agent and granulating the mixture, while mixing and granulating is carried out in one device - a granulator with a ratio of the binder solution and the siliceous component from 1: 5 to 1: 1.2, after which the raw granules are subjected to heat treatment: drying and calcination, while the total content is alkaline oxides in the finished material is from 5 to 20 wt.%.

In addition, to further reduce the specific gravity of the material, carbon, and / or carbonate, and / or carbide type gas blowers can be used.

To increase the productivity of the granulator, before the granulation, the components are pre-mixed to obtain a loose unconsolidated mixture, which is compacted into compact granules during granulation.

To accelerate the process of obtaining a binder solution, ground glassy sodium silicate is dissolved in an aqueous solution of sodium carbonate and / or other water-soluble alkali metal compounds.

To obtain aggregated granules, raw granules are further processed on a disk or screw granulator or other forming device.

Raw granules are used as a charge for the manufacture of building material in the form of an array: plates, blocks, panels and other products.

The method is as follows.

Rocks containing silica in finely dispersed and chemically active form, mainly in the form of opal, quartz or zeolite, are used as a siliceous raw material component. Such rocks include flasks, tripoli, diatomites, spongilites, radiolarites, zeolites, siliceous loams, as well as their transitional varieties, including those with a clay component. Waste and dumps of technogenic origin, in particular silica fume as a by-product of metallurgical production, as well as mixtures of the listed raw materials, can also act as a siliceous component.

As a binder solution, which is also an alkali-containing component, multicomponent aqueous solutions of sodium and / or potassium silicates with a silicate module are used in the range of 1-4, soda ash, potash, alkali metal hydroxides, alkali metal sulfates, alkali metal nitrates, obtained by joint dissolving the corresponding chemical compounds or industrial waste containing the compounds, and the list of components is not exhaustive.

The composition of the binder solution must include at least 15% sodium silicate and at least one alkali metal salt or hydroxide from the above list.

The ratio of the siliceous component and the binder solution is selected based on the composition of the binder solution, the granulation method and the required alkaline oxide content in the finished material, which should be from 5 to 20 wt.%.

The water content in the binder solution is determined based on the required proportion of alkaline oxides in the final product, comprising from 5 to 20 wt.% Alkali metal oxides and the granulation technology used.

The time to obtain a homogeneous binder solution and, accordingly, the productivity of the equipment will be limited by the rate of dissolution in water of glassy sodium silicate, which comes in the form of crushed glass (silicate block), the dissolution of which with the formation of an alkaline silicate solution requires high temperature and a long time.

It is known that the industrial process of dissolving technical glassy sodium silicate (block of silicate) to produce a sodium silicate solution requires hydrothermal treatment at temperatures above 100 ° C, takes several hours and, as a rule, is carried out in autoclaves, which is associated with additional costs and complication of the process .

Therefore, when using glassy sodium silicate as a raw material for the manufacture of a binder, the intensification of its dissolution process and the combination of dissolution with other technological operations can significantly reduce the cost and simplify the process, increase the productivity of the equipment.

It is known that the rate of dissolution (corrosion) of silicate glasses (which include sodium silicate glasses and a silicate block, in particular) is limited by the formation on the glass surface of a layer of hydrated silica, which inhibits the diffusion of alkaline ions, and therefore can be significantly (several times) accelerated by mechanical removal of the upper hydrated glass layer, which is achieved by wet grinding (the effect of mechanical activation of surface reactions).

The dissolution of sodium silicate glasses, including glassy sodium silicate, in an aqueous medium is significantly accelerated with increasing temperature.

Also, the dissolution rate (corrosion) of glasses, which include glassy sodium silicate, significantly increases in solutions of sodium and potassium salts having an alkaline reaction, for example, in solutions of soda and potash.

The proposed method uses all three methods of activating the dissolution of sodium silicate in water - mechanical, thermal and chemical.

A distinctive feature of the proposed method is the one-stage preparation of a multicomponent binder solution, combining wet grinding of a silicate block, mechanical activation of dissolving a silicate block in a hydrothermal treatment, chemical acceleration of dissolution due to the inclusion of readily soluble in water and corrosive against glass of carbonates and hydroxides of alkali metals, creating a strongly alkaline environment when dissolved.

In this case, the mixture is heated to a temperature of 80-110 ° C due to both the heat of dissolution of the components in water and the mechanical energy of the grinding, which passes into heat directly in the mixture of components, which saves energy and simplifies the technology.

The combination of mechanical, thermal and chemical activation of dissolving the silicate block reduces the grinding time and energy consumption for grinding by at least 2–3 times depending on the composition of sodium silicate (silicate block) and eliminates the grinding of the silicate block as a separate technological operation .

Thus, in the proposed method, the binder solution is obtained in one step, under conditions that provide maximum equipment performance, which is determined by the dissolution rate of the silicate block, as the most hardly soluble component.

To obtain a binder solution, dry components (sodium silicate and soluble salts of alkali metals) and water are loaded into a ball mill, attritor, vibration mill or other wet milling machine of periodic or continuous action, where the combined technological operation of grinding, mixing, dissolving and hydrothermal treatment is carried out the reaction mixture, passing at a temperature of 80-110 ° C for 10-180 minutes (with a batch process) or until all or most of the components are dissolved with continuous the process of preparing the binder solution.

Combining operations in one device reduces the number of units of equipment, eliminates interoperational transportation of semi-finished products and thereby reduces capital costs for equipment, and also simplifies its operation.

The use of highly viscous solutions of sodium and / or potassium silicates, which are colloidal in nature, as a basis for a binder solution makes it possible to exclude crystallization of water-soluble salts of alkali metals in a solution, as a result of which, upon heat treatment of raw granules, the binder solution, losing water and increasing viscosity, directly transfers to low-melting glass at temperatures below the glass transition temperature, bypassing the formation of crystalline phases during the synthesis of the glass phase and maintaining almost perfectly homogeneous amo fnoe (non-crystalline) state.

Due to the direct transition of the binder solution to the glass phase, the formation of closed pores occurs at a lower temperature and / or lower content of sodium oxide, which increases the degree of foaming and reduces raw material costs.

Thus, the method can be attributed to the nanotechnology of colloidal silica, namely to sol-gel processes of low temperature synthesis.

Next, a powdery silica component is mixed with a binder solution, and, if necessary, with a gasifier (examples 8-10) to obtain raw granules.

In the proposed method, granulation, combining in one device a mixture of a siliceous component and a binder solution, is carried out in a mixer-granulator of a speed, plate, blade or other type, providing a single-stage production of raw granules from a dry powder of a siliceous component and a complex binder, dosed in a proportion that provides the necessary composition of raw granules.

Received in the mixer-granulator wet raw granules are dried to a final moisture content of 1-15%, providing the necessary flowability, strength and water resistance of raw granules. The type of dryer is not significant.

The final technological operation is the high-temperature heat treatment (foaming) of raw granules. The foaming temperature, depending on the composition and production technology of raw granules, is from 750 to 1100 ° C, the duration of stay in rotary drum furnaces of continuous action is from 5 to 60 minutes.

Fluidized bed furnaces or similar aggregates with aerodynamic heating of raw granules can also be used for foaming.

To obtain material in the form of an array, including blocks, plates and shaped products, raw granules are placed in a heat-resistant form coated with a release layer, for example, based on kaolin powder, and are heat-treated at a foaming temperature, followed by annealing, the duration of which depends on geometric dimensions array and material properties.

Raw granules produced by this method are used for the production of foamed glass ceramic gravel or slab material in conveyor hearth furnaces by the method of producing a continuous tape of foamed material, to produce foam glass ceramic (in the absence of annealing) or plate material (solid), in the presence of an annealing furnace.

The advantages of the proposed method:

- improvement of material properties (decrease in density and decrease in volumetric water absorption),

- simplification of technology (combining mixing and granulation in one technological operation,

- cheaper raw materials (replacing caustic soda with sodium silicates and soda ash), the possibility of obtaining a fine fraction (in contrast to a plate granulator).

The following are examples of specific implementation of the method.

Example 1

For the preparation of raw granules, natural diatomite of the following composition was used:

The following components were used to prepare the binder solution:

silicate block (sodium silicate) with silicate module 3 (25% wt. Na ₂ O) soda ash, tap water with a salinity of 1-1.5 g / l in the following ratio of components:

To prepare the binder solution, silicate block, crushed to a size of 0-3 mm, soda and water were loaded into a wet grinding attritor (vertical ball mill) with a capacity of 30 l with ball loading from steel balls with a diameter of 6 mm, weighing 25 kg. 5 minutes after the start of grinding, the loading temperature reached 80 ° C and was maintained by supplying water to the attritor's water jacket at a level of 90-100 ° C. 20 minutes after the start of grinding, the solution became transparent, which indicates the complete dissolution of the silicate block and soda. When the solution is cooled to 20 ° C, the solution does not crystallize.

Dried ground diatomaceous earth with a physical moisture content of 3% was placed in a 50 L high-speed mixer-granulator. The binder solution obtained previously was added to a working mixer-granulator. 80 seconds after the dosing of the binder solution was completed, the dusting of the solution ceased, after 110 seconds the granulation was completed.

The finished mixture of raw granules was dried in a rotary drum dryer at a temperature of 200 ° C. Dried raw granules have a dense texture, dark brown color, satisfactory water resistance.

After mixing with a separation medium in the form of kaolin in an amount of 5%, the raw granules were fired (expanded) in a rotary drum furnace at a temperature of 880 ° C; the average residence time of the granules in the heating zone was 10 minutes.

The obtained granular foamglass ceramic has the following characteristics:

Volumetric water absorption - 0.8-1.0%.

Example 2

A part of the raw granules obtained in Example 1, after mixing with a separation medium in the form of kaolin in an amount of 5%, was fired (expanded) in a rotary drum furnace at a temperature of 930 ° C; the average residence time of the granules in the heating zone was 10 minutes.

The structure of the granules is large-pore, the degree of vitrification is high (the cell walls are transparent), a tendency is observed for the granules to stick together during firing.

Volumetric water absorption - 1.5%.

Example 3

Part of the raw granules obtained in example 1, after mixing with a separation medium in the form of kaolin in an amount of 5%, was fired (expanded) in a rotary drum furnace at a temperature of 830 ° C, the average residence time of the granules in the heating zone was 10 minutes.

The structure of the granules is finely porous, the degree of vitrification is moderate (the cell walls are cloudy).

Volumetric water absorption - 3.5%.

Example 4

For the preparation of raw granules, natural diatomite of the following composition was used:

The following components were used to prepare the binder solution: silicate block (sodium silicate) with silicate module 3 (25% wt. Na ₂ O), soda ash, tap water with a salinity of 1-1.5 g / l in the following ratio of components:

To prepare the binder solution, silicate block, crushed to a size of 0-3 mm, soda and water according to the recipe were loaded into a wet grinding attritor (vertical ball mill) with a capacity of 30 l with ball loading from balls with a diameter of 6 mm, weighing 25 kg. 5 minutes after the start of grinding, the loading temperature reached 80 ° C and was maintained by supplying water to the attritor's water jacket at a level of 90-100 ° C. After 28 minutes, the solution became clear, indicating complete dissolution of the silicate block and soda.

At temperatures below 40 ° C, the binder solution crystallizes with the release of a fine crystalline soda precipitate.

Dried ground diatomaceous earth with a physical moisture content of 3% was placed in a 50 L high-speed mixer-granulator. The binder solution obtained previously was added to a working mixer-granulator. 85 seconds after the dosing of the binder was finished, dusting ceased, after 120 seconds the granulation was completed.

The finished mixture of raw granules was dried in a rotary drum dryer at a temperature of 200 ° C. Dried raw granules have low strength, dark brown color, low water resistance, adsorb moisture from the air with the formation of a layer of crystals of ten-sodium sodium carbonate.

After mixing with a separation medium in the form of kaolin in an amount of 5%, the raw granules were fired (expanded) in a rotary drum furnace at a temperature of 880 ° C; the average residence time of the granules in the heating zone was 10 minutes.

The obtained granular foamglass ceramic has the following characteristics:

Volumetric water absorption - 4.5%.

Example 5

For the preparation of raw granules, natural diatomite of the following composition was used:

The following components were used to prepare the binder solution: silicate block (sodium silicate) with silicate module 3 (25% wt. Na ₂ O), soda ash, tap water with a salinity of 1-1.5 g / l in the following ratio of components:

To prepare the binder solution, silicate block, crushed to a size of 0-3 mm, soda and water according to the recipe were loaded into a wet grinding attritor (vertical ball mill) with a capacity of 30 l with ball loading from balls with a diameter of 6 mm, weighing 25 kg. 5 minutes after the start of grinding, the loading temperature reached 85 ° C and was maintained by supplying water to the attritor's water jacket at a level of 90-100 ° C. After 35 minutes, the solution became clear, indicating complete dissolution of the silicate block and soda.

Dried ground diatomaceous earth with a physical moisture content of 3% was placed in a 50 L high-speed mixer-granulator. The binder solution obtained previously was added to a working mixer-granulator. 90 seconds after the dosing of the binder was completed, the dusting of the mixture ceased, after 125 seconds the granulation was completed.

The finished mixture of raw granules was dried in a rotary drum dryer at a temperature of 200 ° C. Dried raw granules have a dense texture, dark brown color, satisfactory water resistance.

After mixing with a separation medium in the form of kaolin in an amount of 5%, the raw granules were fired (expanded) in a rotary drum furnace at a temperature of 880 ° C; the average residence time of the granules in the heating zone was 10 minutes.

The obtained granular foamglass ceramic has the following characteristics:

Volumetric water absorption - 1.5%.

Example 6

For the preparation of raw granules, natural diatomite of the following composition was used:

The following components were used to prepare the binder solution: silicate block (technical sodium silicate) with silicate module 3 (25% wt. Na ₂ O), soda ash, tap water with a salinity of 1-1.5 g / l in the following ratio of components:

To prepare the binder solution, silicate block, crushed to a size of 0-3 mm, soda and water were loaded into a wet grinding attritor (vertical ball mill) with a capacity of 30 l with ball loading from steel balls with a diameter of 6 mm, weighing 25 kg. 5 minutes after the start of grinding, the loading temperature reached 80 ° C and was maintained by supplying water to the attritor's water jacket at a level of 90-100 ° C. 20 minutes after the start of grinding, the solution became transparent, which indicates the complete dissolution of the silicate block and soda.

When the solution is cooled to 20 ° C, the solution does not crystallize.

Dried ground diatomaceous earth with a physical moisture content of 3% was placed in a 50 L high-speed mixer-granulator. The binder solution obtained previously was added to a working mixer-granulator. 80 seconds after the dosing of the binder solution was completed, the dusting of the solution ceased, after 110 seconds the granulation was completed.

The finished mixture of raw granules was dried in a rotary drum dryer at a temperature of 200 ° C. Dried raw granules have a dense texture, dark brown color, satisfactory water resistance.

After mixing with a separation medium in the form of kaolin in an amount of 5%, the raw granules were fired (expanded) in a rotary drum furnace at a temperature of 900 ° C, the average residence time of the granules in the heating zone was 10 minutes.

The obtained granular foamglass ceramic has the following characteristics:

Volumetric water absorption - 4.2%.

Example 7

A part of the raw granules obtained in Example 1 in an amount of 700 g were poured into a mold with a lid of 200 × 200 × 100 mm in size stainless steel, previously coated with a suspension of kaolin in a 2% aqueous solution of polyvinyl alcohol, after which the material was subjected to heat treatment (foaming) in a muffle furnace in the following mode: heating to 880 ° C at a rate of 5 ° C / min, holding at 880 ° C for 20 minutes, slow cooling to 850 ° C for 20 minutes, cooling to 750 ° C for 30 minutes, further - natural cooling in a closed oven to room temperature.

The resulting foam glass ceramic block with a density of 165 kg / m ³ has a uniform porous structure with a pore diameter of up to 2 mm, compressive strength of 22-25 kg / cm ² . Volumetric water absorption 2.3%.

Example 8

For the preparation of raw granules, natural diatomite of the following composition was used:

The following components were used to prepare the binder solution: silicate block (technical sodium silicate) with silicate module 3 (25% wt. Na ₂ O), soda ash, ground marble with a specific surface of 5 thousand cm ² / g, as a carbonate blowing agent - tap water with a salinity of 1-1.5 g / l in the following ratio of components:

To prepare the binder solution, silicate block, crushed to a size of 0-3 mm, soda and water were loaded into a wet grinding attritor (vertical ball mill) with a capacity of 30 l with ball loading from steel balls with a diameter of 6 mm, weighing 25 kg. 5 minutes after the start of grinding, the loading temperature reached 80 ° C and was maintained by supplying water to the attritor's water jacket at a level of 90-100 ° C. 20 minutes after the start of grinding, the solution became transparent, which indicates the complete dissolution of the silicate block and soda.

When the solution is cooled to 20 ° C, the solution does not crystallize.

Dried ground diatomaceous earth with a physical moisture content of 3% and ground marble powder with a specific surface of 5000 cm ² / g as a carbonate blowing agent were placed in a 50 L high-speed mixer-granulator. The binder solution obtained previously was added to a working mixer-granulator. 80 seconds after the dosing of the binder solution was completed, the dusting of the solution ceased, after 110 seconds the granulation was completed.

The finished mixture of raw granules was dried in a rotary drum dryer at a temperature of 200 ° C. Dried raw granules have a dense texture, dark brown color, satisfactory water resistance.

After mixing with a separation medium in the form of kaolin in an amount of 5% by weight of the charge, the raw granules were fired (expanded) in a rotary drum furnace at a temperature of 900 ° C; the average residence time of the granules in the heating zone was 10 minutes.

The obtained granular foamglass ceramic has the following characteristics:

Volumetric water absorption - 4.6%.

Example 9

For the preparation of raw granules, natural diatomite of the following composition was used:

The following components were used to prepare the binder solution: silicate block (technical sodium silicate) with silicate module 3 (25% wt. Na ₂ O), soda ash, ground silicon carbide with a specific surface of 7000 cm ² / g, tap water with a salinity of 1- 1.5 g / l in the following ratio of components:

To prepare the binder solution, silicate block, crushed to a size of 0-3 mm, soda and water were loaded into a wet grinding attritor (vertical ball mill) with a capacity of 30 l with ball loading from steel balls with a diameter of 6 mm, weighing 25 kg. 5 minutes after the start of grinding, the loading temperature reached 80 ° C and was maintained by supplying water to the attritor's water jacket at a level of 90-100 ° C. 20 minutes after the start of grinding, the solution became transparent, which indicates the complete dissolution of the silicate block and soda.

When the solution is cooled to 20 ° C, the solution does not crystallize.

Dried ground diatomaceous earth with a physical moisture content of 3% and ground silicon carbide powder with a specific surface of 7000 cm ² / g as a carbide blowing agent were placed in a 50 L high-speed mixer-granulator. The binder solution obtained previously was added to a working mixer-granulator. 80 seconds after the dosing of the binder solution was completed, the dusting of the solution ceased, after 110 seconds the granulation was completed.

The finished mixture of raw granules was dried in a rotary drum dryer at a temperature of 200 ° C. Dried raw granules have a dense texture, dark brown color, satisfactory water resistance.

After mixing with a separation medium in the form of kaolin in an amount of 5%, the raw granules were fired (expanded) in a rotary drum furnace at a temperature of 900 ° C, the average residence time of the granules in the heating zone was 10 minutes.

The obtained granular foamglass ceramic has the following characteristics:

Volumetric water absorption - 2.8%.

Example 10

For the preparation of raw granules, natural diatomite of the following composition was used:

The following components were used to prepare the binder solution: silicate block (technical sodium silicate) with silicate module 3 (25% wt. Na ₂ O), soda ash, ground graphite with a specific surface of 8000 cm ² / g as a carbon blowing agent, tap water with mineralization of 1-1.5 g / l in the following ratio of components:

To prepare the binder solution, silicate block, crushed to a size of 0-3 mm, soda and water were loaded into a wet grinding attritor (vertical ball mill) with a capacity of 30 l with ball loading from steel balls with a diameter of 6 mm, weighing 25 kg. 5 minutes after the start of grinding, the loading temperature reached 80 ° C and was maintained by supplying water to the attritor's water jacket at a level of 90-100 ° C. 20 minutes after the start of grinding, the solution became transparent, which indicates the complete dissolution of the silicate block and soda.

When the solution is cooled to 20 ° C, the solution does not crystallize.

Dried ground diatomaceous earth with a physical moisture content of 3% and ground graphite powder with a specific surface area of 8000 cm ² / g as a carbon blowing agent were placed in a 50 L high-speed mixer-granulator. The binder solution obtained previously was added to a working mixer-granulator. 80 seconds after the dosing of the binder solution was completed, the dusting of the solution ceased, after 110 seconds the granulation was completed.

The finished mixture of raw granules was dried in a rotary drum dryer at a temperature of 200 ° C. Dried raw granules have a dense texture, dark brown color, satisfactory water resistance.

After mixing with a separation medium in the form of kaolin in an amount of 5%, the raw granules were fired (expanded) in a rotary drum furnace at a temperature of 900 ° C, the average residence time of the granules in the heating zone was 10 minutes.

The obtained granular foamglass ceramic has the following characteristics:

Volumetric water absorption - 3.0%.

The main properties of the material in comparison with the prototype

Thus, with the optimal technological mode, the proposed method of manufacturing the material provides a significant reduction compared with the prototype bulk density from 200-250 to 150 kg / m ³ as the main indicator that determines the heat-insulating properties of the material, its cost and productivity of the equipment, and also reduces water absorption.

Claims (6)

1. A method of obtaining a granular building material, including preparing a siliceous component, preparing a binder solution, mixing the components, granulating the mixture and heat treatment, characterized in that the binder solution is prepared on the basis of colloidal silica and soluble alkali metal salts by co-wet grinding while dissolving sodium silicate with a silicate module from 1.0 to 4.0, sodium carbonate and / or other water-soluble alkali metal compounds at a temperature of 80-110 ° C, with the following ratio of the main components: glassy sodium silicate - 10-50%, sodium carbonate - 5-40%, water - 40-80%, moreover, the mixing of the siliceous component with a binder solution is combined with the addition of a blowing agent and granulating the mixture, while mixing and granulation is carried out in one device - a granulator with a ratio of binder solution and siliceous component from 1: 5 to 1: 1.2, after which the raw granules are subjected to heat treatment: drying to a moisture content of 1-15% and firing at a temperature of 750-1100 ° C, while the total content of alkali oxides in the finished material is from 5 to 20 wt.%. 2. The method according to claim 1, characterized in that the gas blowing agents of the carbon and / or carbonate type and / or carbide type are used for mixing. 3. The method according to claim 1, characterized in that before granulation, preliminary mixing of the components is carried out to obtain a loose unconsolidated mixture, which is compacted into compact granules during granulation. 4. The method according to claim 1, characterized in that the glassy sodium silicate is dissolved in an aqueous solution of sodium carbonate and / or other water-soluble alkali metal compounds. 5. The method according to claim 1, characterized in that the raw granules are further processed on a disk or screw granulator or other forming device. 6. The method according to claim 1, characterized in that the raw granules are used as a mixture for the manufacture of building material in the form of an array: plates, blocks, panels and other products.