The use of technogenic raw materials to produce a high-alumina chamotte

Abstract

Abstract When fused corundum is crushed, a finely dispersed powder is formed with an Al2O3 content of 93–95%, in the form of substandard material. It is advantageous to utilize this powder to obtain high-alumina chamotte with Al2O3 content of more than 62%. High-alumina aggregate (chamotte) was obtained by semi-dry technology with intermediate briquette molding from a mixture of corundum dispersed powder and enriched kaolin. Based on a final Al2O3 content of 65 wt. % the batch composition of the mass to produce a high alumina aggregate (chamotte) was calculated. From a mixture of dispersed corundum powder and kaolin moistened with a 5–7% technical lignosulfonate solution with a density of 1050 kg·m−3, a briquette was formed at a specific pressing pressure of 15–20 MPa. The briquette was fired at a temperature of 1700°C. The fired briquette had a strength of 164 to 193 MPa. The water absorption of briquettes was 11–12%. The phase composition of the briquette is represented mainly by corundum and mullite. The enriched kaolin did not show sintering effect on fine corundum.