Theoretical and experimental substantiation of obtaining an alloy from flotation tailings of lead-zinc sulfide ore

The article presents the results of thermodynamic and experimental research on the processing of cinders from the firing of Shalkiya deposit lead-zinc ore tailings with the production of siliceous ferroalloys. Thermodynamic modeling carried out using the HSC-6.0 complex based on the Gibbs energy minimization principle showed that the interaction occur with the formation of CaSiO3, FeSiO3, MgSiO3, K2OˑSiO2, FeSi, Fe5Si3, SiC, Fe3Si, Si, SiOg, FeSi2.33, FeSi2, CaSi, Zn, Zng, Pb, Pbg; an increase in the iron amount in the system allows increasing the silicon extraction degree into the alloy at 1800°C to 76%, to reduce the silicon concentration in the alloy from 41 to 24%; FS25 grade ferrosilicon formed at 1752-1867°C in the presence of 88-100% iron, and FS45 grade ferrosilicon – at 1863-1900°C and 20-22.4% iron. Electric melting of a charge containing 63.83% calcined cinder of tailings, 19.15% coke, and 17.02% steel chips allows to obtain FS45 grade ferrosilicon (44.1-43.9% Si) with the extraction of 69.7% silicon and sublimates with the content of 32-38% zinc and lead. The results obtained allow complex processing of lead-zinc sulfide ore tailings with the extraction of not only non-ferrous metals, but also silicon in the ferroalloy

Processing of phosphorites with extraction of phosphorus, obtaining calcium carbide and ferroalloy

The article considers the results of studying the thermodynamic computer modeling of the interaction of phosphorite (Karatau basin, Kazakhstan) with carbon and coke performed using the HSC-10 software package and electric smelting of the phosphorite with coke and steel shavings in an arc furnace. The modeling allowed us to determine the equilibrium extraction degrees of phosphorus into gas (Р2, Р4), silicon into ferroalloy in the form of iron silicides (FeSi2, FeSi, Fe3Si, Fe5Si3, Si) and calcium into CaС2. At temperatures above 1500 °C, regardless of the amount of iron, the extraction degree of phosphorus into gas is more 99%. The resulting ferroalloy contains 21.2-23.8% of Si, 1.6-2.8% of Al; the calcium carbide has a capacity of 288-325 dm3/kg. The extraction degree of silicon into the alloy was 89.8%, calcium in CaC2 – 72.5%, phosphorus into gas – 99.4%. The ferroalloy, formed at the electric smelting of the Chulaktau phosphorite together with coke and steel shavings and containing 24.9-29.8% of Si, is FS25 grade ferrosilicon, and the formed calcium carbide has a capacity of 278-290 dm3/kg and belongs to the third and second grades. The developed technology makes it possible to increase the degree of phosphorites’ comprehensive use two times (up to 87.5%)