RU2287495C1 - Composite blend for manufacturing granulated foamed glass - Google Patents

Abstract

FIELD: composite materials.

SUBSTANCE: invention relates to compositions for manufacturing granulated foamed glass appropriate as effective heat-insulation material and also as light concrete aggregate. Composite blend contains 31.5-23% of heat and power station slag, 3.0-5.0% of electrofilter dust from silicon production plants, 7.0-8.0% of soluble glass, and broken glass as major component.

EFFECT: increased strength of finished granules when compressed in cylinder, increased resource of raw materials, reduced cost, and improved environmental condition.

2 tbl

Description

The invention relates to compositions for producing granulated foam glass, used as an effective heat-insulating material, and also as a filler for lightweight concrete.

Foam glass is known, including: SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₂ , CaO, K ₂ O, Na ₂ O, SiC, TiO ₂ [ac 14130676, IPC С 03 С 11/00, publ. 07/30/88, Bul. No. 28].

The disadvantage of this foam glass is the high foaming temperature of 1443K.

The closest in technical essence and the achieved result to the claimed invention is a raw material mixture for producing granulated foam glass [p. 2243174, IPC С 03 С 11/00, publ. December 27, 2004, Bull. No. 36, (prototype)], including glass breakage, CHP slag, binder — soluble glass and pore former — aluminum sludge in the following ratio of components, wt.%:

Slag CHP 20.0-21.0 Aluminum sludge 1.0-2.0 Soluble glass 8.0-10.0 Glass break rest

The disadvantage of this raw material mixture is the presence of hydrophobic carbon particles in the sludge, which does not allow the introduction of a large amount of blowing agent and, accordingly, reduces the amount of waste used.

The technical result of the invention is to increase the strength of the finished granules by squeezing in the cylinder, expanding the raw material base, reducing costs and protecting the environment.

The technical result is achieved by the fact that in the composite mixture for producing granulated foam glass, including glass breakage, CHP slag, soluble glass and a blowing agent, it is new that dust from silicon electrostatic precipitators is used as a blowing agent in the following ratio of components, wt.%:

Slag CHP 21.5-23 Dust of electrostatic precipitators silicon production 3.0-5.0 Soluble glass 7.0-8.0 Glass break rest

In the composite mixture for the production of foam glass, window and container glass wastes, slag from thermal power plants are used, soluble glass is used as a binder, and dust from electrostatic precipitators of a silicon plant is used as a pore former, which eliminates the costly addition of silicon carbide and carbon black and obtain porous granules from waste from other industries.

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 composite mixture for the production of granular foam glass is as follows: cullet, CHP slag and dust from silicon-based electrostatic precipitators are subjected to joint grinding in a ball mill to a specific charge surface of 400-500 m ² / kg. The resulting mixture is loaded into a plate granulator, moistened with soluble glass with a density of 1.14-1.20 g / cm ³ to a moisture content of 16-18% and granulated. The obtained granules are dried at a temperature of 373-393K, and then foaming is carried out at a temperature of 943-1073K for 6-20 minutes. Foamed granules of foam glass to relieve temperature stresses are laid out in containers with heated sand.

Dust of silicon production electrostatic precipitators contains, wt.%, Fine: SiO ₂ - 55.6; C - 20; SiC - 24; TiO ₂ 0.2; P ₂ O ₅ - 0.2. With this ratio of pore former, foaming of the glasses is ensured at relatively low temperatures of 1003-1063K without crystallization. Crystallization occurs at temperatures above 1063 ° C, resulting in the formation of a crystalline crust, which provides an increase in compressive strength from 2.0 to 2.75 MPa in the cylinder, at a low bulk density.

TPP slag contains up to 33.4% CaO, up to 11.0% Fe ₂ O ₃ , 9.59% pp (production losses, consisting of carbon, water and sulfur), up to 0.60% TiO ₂ , up to 45.41% SiO ₂ .

The addition to the powder of glass of vitrified slag of the TPP, soluble glass and dust of electrostatic precipitators - waste in the production of silicon helps to strengthen the finished granules of foam glass and improves the foaming process during firing.

Joint introduction with dust of electrostatic precipitators of finely dispersed SiO ₂ ; FROM; SiC; TiO ₂ ; P ₂ O ₅ ; SO ₃ and Fe ₂ O ₃ introduced with the slag of the thermal power station positively affects the process of foaming and hardening of foam glass.

When heat treated from a temperature of 793 K, carbon burns out smoothly, which reacts with sulfur trioxide contained in glass and slag to form gaseous oxides

SO ₃ + C → S ^2- + CO + CO ₂

Divalent sulfur S ^{2 -} reacts with iron oxide Fe ₂ O ₃ according to the scheme

S ^2- + Fe ₂ O ₃ → FeS ₂ + O ₂

Carbon with oxygen form carbon dioxide according to the scheme:

C + O ₂ → CO ₂

Active hydrogen is released with water vapor

C + H ₂ O → 2H + CO

The released atomic hydrogen is involved in the decomposition of iron sulfide (metal sulfides)

FeS ₃ + 2H → H ₂ S + Fe

MeS ₂ + 2H → H ₂ S + Me

Pyrite in reducing conditions is restored according to the scheme:

3FeS ₂ + C → 6S + Fe ₃ C ↓

and distributed throughout the entire volume in a finely divided state.

In contact with water vapor released from the granules with a moisture content of up to 2%, there is an intensive gas evolution according to the scheme:

3S + 2H ₂ O → SO ₂ ↑ + 2H ₂ S ↑

as evidenced by the smell of hydrogen sulfide when crushing granules.

The foaming process in the presence of CO, CO ₂ and H ₂ S gases is very intense.

Thus, the introduction of dust from silicon production electrostatic precipitators into a composite mixture containing glass breakage and CHP slag makes it possible to obtain granular foam glass with a uniform porous structure and increases the strength indices at low temperatures of 943–1063 K, and titanium dioxide in dust from electrostatic precipitators in combination with sulfide sulfur, carbon and phosphorus pentoxide promote crystallization without the use of costly fluorine salts.

The granular foam glass obtained by this technology is characterized by a spherical pore shape of a predominantly closed structure.

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

Table 1 Name of components Examples of the proposed composition, wt.% one 2 3 Slag CHP 21.5 22.5 23 Silicon-made electrostatic dust 5 four 3 Soluble glass 7 7.5 8 Glass break 66.5 66 66

Table 2 shows the properties of the obtained materials.

table 2 Raw mix Foaming Temperature, K Property metrics Foaming ratio Bulk density, kg / m ³ The compressive strength in the cylinder, MPa Water absorption,% one 1063 5.2 150 2.00 2.48 2 1033 4.10 170 2,50 3.0 3 1003 3.76 200 2.75 0.71

Analysis of the obtained data allows us to conclude that from the proposed composite mixture receive granular foam glass having a bulk density of from 165 to 200 kg / cm ³ at lower foaming temperatures (1003-1063K) and compressive strength in the cylinder from 2.00 to 2, 75 MPa.

The use of slag from thermal power plants and dust from silicon-based electrostatic precipitators can expand the raw material base, reduce the cost of producing granulated foam glass and at the same time solve the problem of waste disposal and environmental protection and reduce the cost of maintaining dumps.

Claims (1)

A composite mixture for the production of granular foam glass, including glass breakage, CHP slag, soluble glass and a blowing agent, characterized in that it contains silicon electrostatic dust in the following ratio of components, wt.%: Slag CHP 21.5-23 Dust of electrostatic precipitators silicon production 3.0-5.0 Soluble glass 7.0-8.0 Glass break Rest