Abstract
The article presents the results of studies using computer thermodynamic modeling for the extraction of magnesium and heavy non-ferrous metals into the gas phase from the tailings of the Kentau processing plant using the HSC-5.11 Chemistry software package. Studies of the enrichment tailings – nFeSi2 system were carried out in the temperature range 500-2000°С, a pressure of 0.001 bar and a content of FeSi2 (20% and 35% of the tailings mass). Adequate regression equations for the effect of temperature and amount of ferrosilicon on the degree of transition of magnesium, zinc and lead to the gas phase have been obtained. It was found that under equilibrium conditions, the interaction of the enrichment tailings with the reducing agent ferrosilicon, the temperature of the onset of formation of gaseous substances is: for magnesium more than 1000°С; zinc ≥500°С, lead ≥800°С, SiOg ≥ 1300°С. Silicon and iron silicides are reduced in systems already at ≥ 500°С. In the temperature range 733-800°С the degree of zinc transition to gas is 98-98.5% at a maximum content of 20-34% FeSi, whereas magnesium is 95-97.7% at 1775-1850°С in the presence of 30.6-34% FeSi2. Copper contained in the enrichment tailings is completely converted into the resulting alloy, which is classified as a copper-containing ligature (31.7% Si, 63.4% Fe, 4.9% Cu). It was revealed that in the process of complex processing of the tailings of the Kentau enrichment plant in the presence of FeSi2, as a reducing agent, it is possible to extract magnesium, zinc, and lead into the gas phase and obtain a copper-containing ligature that can be used in the smelting of copper steel.