PHYSICAL PROPERTIES OF SLAGS OF CaO – SiO2 – B2O3 SYSTEM CONTAINING 15 % OF Al2O3 AND 8 % OF MgO

Abstract

Influence of the chemical composition of CaO – SiO2 – B2O3 oxide system containing 15 % Al2O3 and 8 % MgO (in this expression  and hereinafter indicated by mass %) on viscosity and crystallization  temperature was studied using experiment method of simplex lattice  planning. Addition of B2O3 to the slags of oxide system expands the  range of slags composition with a low crystallization temperature and  viscosity. Slags with a basicity of 2  –  3, containing 1  –  3  % of B2O3  are characterized by a low crystallization temperature, varying from  1400 to 1450  °С and have high flowability. The viscosity of such slags  when heated to 1550 and 1600  °C does not exceed 0.20 and 0.15  Pa·s,  respectively. An increase in B2O3 content to 4  –  6  % in slags with a  basicity of 2  –  3 is accompanied by a decrease in crystallization temperature to 1350  –  1425  °C with keeping low, not more than 0.15  Pa·s,  viscosity in the range of heating temperatures at 1550 and 1600  °C.  The displacement of formed slags containing 1  –  6  % of B2O3 to the  area of increased basicity up to 3  –  5 preserves their relatively high  fluidity. In this case, with an increase in B2O3 concentration, there is a  clear tendency for the studied oxide system to shift to the region of low  crystallization temperatures. Crystallization temperature of slags with  basicity of 3  –  4 containing 6  % of B2O3 reaches 1400  °С and practically does not exceed 1475  °С of slags with basicity of 4  –  5 containing 1  –  2  % of B2O3 . At temperature of 1600  °C, the viscosity of such  slags varies from 0.15  Pa·s with a basicity of 3 and a content of 5  –  6  %  of B2O3 to 0.25  Pa·s in the basicity range of 4  –  5 with B2O3 content  of 1  –  3  %. A decrease in temperature of the studied oxide system by  50  °C is accompanied by a slight (no more than 0.05  Pa·s) increase in  viscosity.