RU2234483C2 - Raw mixture and method of production of air-entrained articles - Google Patents

Abstract

FIELD: production of air-entrained ceramics; manufacture of building materials.

SUBSTANCE: raw mixture contains the following components, mass-%: compacted micro-silica, 24.5-32; high-calcium flying ash, 50-65; spilled crushed coal lining of electrolyzers, 5-7; sulfated soap, 3-3.5. Proposed method includes preparation of raw mixture by mixing the micro-silica, sulfated soap granulated during supply to granulator in the amount of 1.5-1.8 mass=% with high-calcium flying ash and spilled material of electrolyzer coal lining; method includes also supply of sulfated soap in the amount of 1.5-1.7 mass-% in form of technical foam prepared by air bubbling; then, material is subjected to molding, drying at temperature of 60-80 C and roasting at 1000 C.

EFFECT: improved heat protective characteristics; reduced usage of materials.

3 cl, 2 tbl, 1 ex

Description

The present invention relates to the production of porous ceramics and can be used for the manufacture of building materials.

The closest to the proposed raw material mixture in technical essence and the achieved effect is a raw material mixture, including, wt.%: Silica fume production of crystalline silicon 15-85, high-calcium fly ash from burning brown coal 20-85.

The disadvantage of this mixture is the relatively high thermal conductivity and material consumption of the products (average density is 1120-1460 kg / m ³ ).

The technical result is an improvement in thermal characteristics and a decrease in the material consumption of products.

The technical result is achieved in that the raw material mixture for the manufacture of porous products, including high-calcium fly ash and compacted silica fume with a bulk density of up to 0.5 t / m ³ , additionally contains a spill from the battlefield of the spent coal lining of electrolyzers, and sulfate soap as a blowing agent , with the following ratio of components:

compacted silica fume 24.5-32

high calcium fly ash 60-65

coal spill from the battle

lining of electrolyzers 5-7

sulfate soap 3-3.5

Silica fume is an ultrafine waste of crystalline silicon production, having a high specific surface area of 25 ... 34 m ² / g, low bulk density of 150 ... 250 kg / m ³ and containing amorphous silicon oxide up to 93 wt.%. The chemical composition of silica fume, wt.%: SiO ₂ - 86-93; Fe ₂ O ₃ - 0.14-1.28; MgO - 1.03-1.20; Na ₂ O - 0.39-0.46; K ₂ O - 0.28-0.42; Al ₂ O ₃ - 0.7-1.05; CaO 0.26-0.44; RFP 3.7-5.29.

Due to its low bulk density, silica fume needs to be compacted before use (mechanical compaction, granulation, etc.) to reduce transportation costs and reduce dusting. The bulk density of the compacted silica fume reaches 0.5 t / m ³ .

A spill from the battle of the spent coal lining of electrolysis cells is a waste of aluminum production resulting from the overhaul of electrolysis cells. After crushing and screening, large pieces of the dismantled lining are disposed of in the metallurgical industry, and the spill from crushing with a particle size of up to 5 mm does not find any use for itself and is transported to the dump. The chemical composition of the waste, wt.%: SiO ₂ - 22.4; Al ₂ O ₃ - 15.01; Fe ₂ O ₃ - 2.05; CaO - 2.6; MgO - 1.58; F ⁺ - up to 15; Na ⁺ - up to 15; C - up to 67. The prevailing particle size (over 90%) - up to 1.25 mm. Bulk density - 760 kg / m ³ .

High-calcium fly ash is formed from the burning of coal from the Kansk-Achinsk coal basin and has the following composition, wt.%: SiO ₂ - 40 ... 55; Al ₂ O ₃ - 4 ... 10; Fe ₂ O ₃ - 6 ... 14; CaO - 20 ... 35; MgO - 3 ... 6; K ₂ O - 0.3 ... 1.5; Na ₂ O - 0.2 ... 0.5; SO ₃ - 0.9 ... 5; CaO _sv - 0.3 ... 13; combustible impurities - not more than 2.

Sulphate soap is a product that is removed from the surface of the black liquors of sulphate-cellulose production when cooking pulp from coniferous and deciduous species of wood, and is a buttery mass from dark yellow to dark brown. In accordance with TU 13-0281078-28-118-88, the chemical composition of sulfate soap, wt.%: Fatty, resin acids and unsaponifiable substances - not less than 40 ... 45%; water - no more than 35 ... 50; total alkali in terms of NaOH - not more than 9. Soap is contaminated with lignin, tannides and dyes, as well as mineral components.

The introduction of sulfate soap provides the formation of optimal differentiated porosity in size. In this case, the large pores formed by the foam are combined with the small ones obtained by air entrainment. This determines the increase in strength and thermal characteristics of the shard.

The combination of silica fume, high-calcium fly ash and coal lining causes the formation of high-strength, long-lasting crystalline phases during firing - feldspars, diopside, wollastonite, reinforcing shards.

A method of manufacturing porous products includes preparing a mixture, drying and firing products from a raw material porous in two stages. The first stage is provided by air entrainment when mixing silica fume, 1.5 ... 1.8 wt.% Compressed with the addition of sulphate soap, fly ash and spillage from the battle of the coal lining of electrolyzers due to the surface-active properties of fatty and resin acids. The second stage of porization is carried out by introducing technical foam prepared by bubbling an aqueous solution of sulfate soap (1.5 ... 1.7 wt.%) Into the above mass.

Example

The manufacture of the material is as follows. Silica fume is placed in a granulator while feeding an aqueous solution of sulfate soap. Silica fume, compacted to a bulk density, is mixed with a rotary mixer with fly ash, sprinkle from the battle of a coal lining and water for 1 ... 3 min. Technical foam made by sparging air with an aqueous solution of sulfate soap at a 1: 1 ratio of water to sulfate soap is introduced into the resulting mixture. The finished mixture is poured into molds, sent for drying at 60 ... 80 ° C. Products are fired at a temperature of 1000 ° C.

The compositions of raw mixtures and the physical and technical characteristics of products based on them are given in table. 1 and 2.

Literature

1. RF patent No. 2086517, MKI ⁶ C 04 V 35/14, 35/16. Tacki L.N., Lokhova N.A., Gershanovich G.L., Senichak E.B. The raw material mixture for the manufacture of wall ceramic products // Bull. Revelation Inventor, 1997, No. 22.

Claims (2)

1. The raw material mixture for the production of porous ceramics, including high-calcium ash and silica fume, characterized in that as a silica fume use compacted silica fume with a bulk density of up to 500 kg / m ³ , the mixture additionally contains a spill from the battle of a coal lining of electrolyzers, and as an air entrainment and pore-forming additives - sulfate soap, in the following ratio of components, wt.%: Sealed silica fume 24.5-32 High calcium fly ash 60-65 Coal from the battlefield lining of electrolyzers 5-7 Sulfate soap 3-3.5 2. A method of manufacturing ceramic foam products and a raw material mixture containing high-calcium ash and silica fume, comprising preparing a mixture, molding, drying and firing, characterized in that when using the mixture according to claim 1, silica fume is compacted by granulation when feeding 1.5-1 to the granulator, 8 wt.% Sulfate soap in the form of an aqueous solution, after which the compacted silica fume is mixed with high-calcium ash - entrainment, spilled from the battle of the coal lining of electrolyzers and water with a rotary mixer, then 1.5-1.7 is introduced into the resulting mixture wt.% sulfate soap in the form of technical foam, prepared by sparging with air.