Optimization of the electrothermal production of ferrosilicon from the leaching tailings of the oxidized copper ore of Almaly

Abstract

The increase in the integrated use of oxidized and mixed copper ores largely depends on the creation of a technology that allows not only to extract copper, but also to obtain marketable products from non-metallic components. The article presents the results of experimental studies of electric melting of leaching tailings of copper oxidized ore of the Almaly deposit containing by weight, %: 70.9 SiO2, 15.9 Al2O3, 2.1 MaO, 2.4 CaO, 3.6 K2O, 2.2 Na2O, 2.0 Fe2O3, 0.4 TiO2, 0.2 BaO, 0.2 CuO to obtain ferrosilicon. The studies were carried out using a single-electrode single-phase arc furnace with adjustable power, as well as the method of rotatable second-order research (Box-Hunter plan). The influence of the amount of coke and steel chips on the degree of silicon extraction into the alloy and its grade was determined. It was found that with a constant amount of coke, an increase in the charge of steel chips increases the extraction of silicon into the ferroalloy and reduces the concentration of Si in it. The influence of coke on the behavior of silicon has a lesser effect. Based on the obtained volumetric and planar images of changes in the extraction of silicon into the alloy and its composition, geometric optimization of the process was carried out. It was found that ferrosilicon grade FeSi25 with the extraction of 70-75% silicon in it is formed in the presence of 30-31.3% coke, 31.3-32.0% steel chips. To obtain ferrosilicon of the FeSi45 brand, with the extraction of 70-76% silicon, the amount of coke should be 32.2-36.3%, and steel chips 25.6-28.3% of the mass of the brags; in the presence of 24-25.2% of steel chips, 30.7-36.3% of coke, ferrosilicon of the FeSi50 brand should be smelted from the tailings.