THERMODYNAMIC AND EXPERIMENTAL RESEARCH OF EFFECTS OF TEMPERATURE AND PRESSURE ON THE PRODUCTION OF SILICON ALLOY, CALCIUM CARBIDE, AND PHOSPHORUS FROM CHILISAY PHOSPHORITES
The article presents the results of a study on the effect of pressure and temperature on the processing of phosphorites of the Aktobe basin of the Chilisay deposit to produce phosphorus, calcium carbide and siliceous ferroalloy. The studies were carried out by thermodynamic modeling using the HSC-6.0 software package, as well as by electric melting in an arc furnace. It was found that under equilibrium conditions, a decrease in pressure from 1 to 0.01 bar increases the degree of silicon extraction into the alloy and the silicon content in the temperature range of 1900-2100 °C, amounting to 83.04 and 53.88 %, respectively, at a pressure of 0.01 bar and 2100 ° C. Pressure reduction reduces the degree of calcium extraction into the alloy from 30.05 % (2000°C) up to 12.78 %; (1500 °C) and a capacity of calcium carbide from 189.57 to 96.73 dm3/ kg. Reducing the pressure reduces the temperature of the complete transition of phosphorus to gas from 1400 to 1100 °C. Reducing the pressure does not significantly change the coefficient of integrated use of raw materials (it varies from 74.04 to 76.25 %), however, 1 bar is optimal, at which the extraction of calcium into the alloy is maximum. By electric melting of a charge consisting of 62 % phosphorite, 25 % coke, 13 % steel shavings, a ferroalloy containing 43.8 % Si and calcium carbide with a capacity of 198 dm3/kg was obtained.