RU2243174C1 - Raw mixture for pelletized glass foam - Google Patents

Abstract

FIELD: building materials, in particular effective heat insulating materials.

SUBSTANCE: claimed mixture contains (mass %): ach from heat-electric generation plant 20.0-21.0; slurry form aluminium manufacturing 1.0-2.0; soluble glass 8.0-10.0; and balance: glass scrap.

EFFECT: reduced bulk density; increased squeeze strength; decreased foaming temperature and cost; as well as superset source of raw materials.

2 tbl

Description

The invention relates to construction materials, and in particular to a technology for the manufacture of effective heat-insulating materials.

Known foam glass obtained from glass breakage and carbon pore-forming additives - coke [and.with. USSR No. 550348, cl. C 03 C 1/00, publ. 1974].

The disadvantages of this mixture include the high cost and bulk density of the resulting products in the synthesis of foam glass in oxidizing conditions.

The closest in technical essence and the achieved result to the invention is a raw material mixture for the manufacture of foam glass [and.with. USSR No. 844597, class S 03 S 1/00, bull. No. 25 dated 07/07/81], including glass breakage and a carbon pore-forming additive - shungite.

The disadvantage of this raw material mixture is the high foaming temperature and low compressive strength of the granules.

The technical result of the invention is to reduce the bulk density, increase the compressive strength in the cylinder, reduce the foaming temperature and the cost of foam glass and expand the raw material base.

The technical result is achieved by the fact that in the raw mixture to obtain granular foam glass, including glass breakage and a blowing agent, the new is that it additionally contains slag from a thermal power station and a binder - soluble glass, and as a blowing agent - aluminum sludge and in the following ratio of components, wt .%:

Slag CHP 20.0-21.0

Sludge from aluminum production 1.0-2.0

Soluble glass 8.0-10.0

Glass Break Else

Comparative analysis with the prototype allows us to conclude that the inventive composition of the raw material mixture for producing granulated foam glass differs from the prototype in the introduction of new components: CHP slag, aluminum sludge and soluble glass.

Thus, the claimed technical solution meets the criterion of "novelty."

And the use of these components in the claimed quantitative ratios provides a decrease in bulk density, increased strength, lower foaming temperature and the cost of foam glass.

Thus, the inventive raw material mixture for producing granulated foam glass meets the criterion of "inventive step".

The raw mix uses window and container glass waste, slag from thermal power plants, soluble glass as a binder, and carbon-containing and fluorine-containing alkaline waste obtained from aluminum production (aluminum sludge) as a pore former.

The manufacture of granular foam glass is based on a powder method, which involves the preparation of a finely divided charge consisting of glass powder, CHP slag and a blowing agent, granule formation, sintering of the charge with its simultaneous porization, fixing the porous structure and relieving temperature stresses.

The manufacturing technology of the raw material mixture for the production of foam glass is as follows: cullet, CHP slag and pore former - aluminum sludge, are subjected to joint grinding in a ball mill (vibration mill) to a specific charge surface of 400-500 m ² / kg.

The resulting mixture is moistened with soluble glass with a density of 1.18-1.20 g / cm ³ to a moisture content of 16-18% and granulated on a plate granulator. The granules are dried at a temperature of 373-393K, then foaming is carried out by thermal shock: in a furnace heated to a temperature of 1003-1063K, the granules are installed in the furnace and kept at set temperatures of 6-20 minutes. In laboratory conditions, foamed granules to relieve temperature stresses are laid out in a container with heated sand.

Sludge is a black material with a particle size of from 0.071 to 10 mm. It consists of flotation tailings, electrostatic dust, gas cleaning sludge and coal foam, which are pumped to the sludge storage in the form of pulp and accumulate in dumps, polluting the natural pool. The sludge contains fluorine compounds, consisting mainly of cryolite, Na ₃ AlF ₆ (8-10%) with a small amount of NaF and AlF ₄ (4-6%), fluorite CaF ₂ (4-6%). In addition, the sludge contains a large amount of soda (5-7 wt.% R ₂ O), as well as carbon, sulfate and sulfide sulfur. The content of non-carbonate carbon in the sludge is up to 60.0 wt.% In the form of metamorphosed carbon particles of graphite.

Introduction to the composition of the mixture to obtain foam glass slurry of aluminum production in the amount of 1.0-2.0 wt.% Provides the introduction of an alkaline component without the introduction of expensive soda, which is fluff, lowering the foaming temperature, as well as blowing agents: fluorine, carbon and sulfur instead of expensive fluorine-containing compounds (cryolite, etc.).

When Na ₂ CO ₃ · H ₂ O is present in the sludge, it begins to decompose when the temperature rises and is smooth, lowering the foaming temperature. The resulting carbon dioxide interacts with carbon, forming carbon monoxide, which contributes to the expansion of the granules.

Alkalis also increase the plasticity of the mass and the final strength of the raw granules and improve the viscosity properties of the mixture during firing.

The addition of vitrified slag of CHP, soluble glass and aluminum sludge to the glass powder contributes to the hardening of raw granules and improves the foaming process during firing.

The use of soluble glass with aluminum sludge in the granulation of foam glass on a plate granulator increases the strength of dry granules.

When mixing soluble glass diluted with water with a raw mixture contained in the sludge, cremnefluoride reacts with it:

Na ₂ SiF ₆ + 2 (Na ₂ O · SiO ₂ + H ₂ O) = 6NaF + 3SiO ₂ · nH ₂ O

Sodium silicofluoride and soluble glass partially react with each other, partially forming solid solutions.

When diluting a solution of soluble glass with water, alkaline silicates are hydrolyzed.

Na ₂ O · SiO ₂ + mH ₂ O = 2NaOH + nSiO ₂ (m-1) H ₂ O

2NaOH + Si + Н ₂ О = Na ₂ O · SiO ₂ + 2Н ₂

In very dilute solutions, alkaline silicates turn out to be almost completely hydrolyzed to NaOH and SiO ₂ . Under the action of water, glassy alkaline silicates contain different amounts of hydrated water, which positively affects the foaming of granules.

The hardening of raw granules based on glass and CHP slag with aluminum sludge during mixing with soluble glass with a density of 1.18-1.20 occurs mainly due to compaction of silica gel formed from a solution of soluble glass under the influence of the chemical and coagulating action of sodium silicofluoride formed from cryolite, as well as sludge present in the composition.

The liberated colloidal silica adheres firmly to the surface of solid particles and cements them.

When the raw material mixture is heated, a liquid phase appears due to fusible eutectics and compounds. With the appearance of a sufficient amount of the liquid phase, the viscosity of the pyroplastic mass decreases and reaches a value when, under the influence of the dynamic pressure of the evolving gaseous phase, the material is plastically deformed. In the range of foaming temperatures, the liquid phase formed from the components of the raw material mixture creates an optimal viscosity that provides the capsulation of gas bubbles while counteracting the gas pressure in the bubbles with a sharp decrease in the perforation of the walls of the resulting pores. In this case, intense and uniform porosity of the material takes place, since all the evolved gases are held in mass without breaking the walls and without forming caverns.

The formation of pores in the material also contributes to the remainder of the undecomposed soluble glass.

The joint introduction of fluorine-containing compounds, carbon and sulfur contained in the sludge contributes to the partial crystallization of the granules, increasing their strength.

Fluorine-containing compounds, namely, CaF ₂ , is simultaneously a flux that lowers the foaming temperature. However, the carbon content is limited to 1.0-2.0%, since an increase in the concentration of sludge slows down the processes of silicate formation in the presence of hydrophobic carbon particles with respect to the silicate melt.

Thus, the introduction of sludge into a raw material mixture containing glass breakage and CHP slag makes it possible to obtain foam glass with a uniform porous structure and increases the strength indices at low temperatures of 1003-1063K.

At the same time, the introduction of fluorine in combination with sulfide sulfur and carbon promotes crystallization without the use of expensive fluoride salts, which increases the strength of the finished product.

Table 1 shows the specific compositions of the mixtures for the preparation of granulated foam glass.

Table 2 shows the properties of granular foam glass of the proposed and known mixtures.

Analysis of the obtained data allows us to conclude that from the proposed raw material mixture, granular foam glass is obtained having a bulk density of 150-200 kg / cm ³ at lower foaming temperatures of 1003-1063K, water absorption is reduced and crushing strength in the cylinder is increased, which makes it possible to reduce consumption process fuel by lowering the foaming temperature.

It is also important to expand the raw material base for the production of granular foam glass through the use of slag from thermal power plants and the disposal of sludge from aluminum production. This allows you to reduce the cost of granular foam glass, and the disposal of waste helps to protect the environment and eliminates the cost of maintaining dumps.

Claims (1)

The raw material mixture for producing granulated foam glass, including glass breakage and a blowing agent, characterized in that it additionally contains CHP slag and a binder - soluble glass, and aluminum production slurry as a blowing agent and in the following ratio, wt.%: Slag CHP 20.0 - 21.0 Sludge from aluminum production 1.0 - 2.0 Soluble glass 8.0 - 10.0 Glass break rest