Electric smelting of phosphorites with production of a ferroalloy, calcium carbide and sublimation of phosphorus

Abstract

The article presents the results of a study of the interaction of phosphorites from the Chulaktau deposit of the Karatau basin with coke and steel shavings. The studies were carried out by computer thermodynamic modeling using the HSC-10 software package, together with mathematical planning of experiments, as well as by electric phosphorite melting in an electric arc furnace. On the basis of the conducted studies it was established that the joint formation of intermediate products from the systems Ca₃(PO₄)₂-SiO₂-C-Fe is possible at the temperature ˃ 1635-1702ºC. Based on the obtained volumetric and planar images of the coke and steel shavings effect on the technological parameters of the phosphorite’s electric smelting, it was found that in order to produce FS25 grade ferrosilicon containing 20-30% of Si and calcium carbide with a capacity of 245.1-248.1 dm³/kg (2^nd grade), the process should be carried out in the presence of 52-58% of coke and 24.4-38% of steel shavings. In this case, the extraction degree of silicon into the ferroalloy was 70-80%, and calcium into calcium carbide – 60-70%.