Abstract
The article examines the results of studies on the production of ferrosilicon from tripoli -a sedimentary rock consisting of opal-like silica.The main part of tripoli is amorphous silica.The studies included the thermodynamic modeling using the HSC-6.0software package, based on the minimum Gibbs energy principle, combined with the second-order rotatable designs and electric melting of tripoli in an arc furnace.It was found that the interaction products in a tripoli-carbon-iron system under equilibrium conditions are FeSi 2 , Fe 3 Si, FeSi, Fe 5 Si 3 , SiC, SiO (g) , Al, Si.Formation of FeSi and Fe 3 Si occurs at 1200°С; of Fe 5 Si 3 and Si -at 1400°С; of FeSi 2 and SiC -at 1500°С; of aluminum -at 1700°С.An increase in the amount of iron from 25 % to 50 % by weight of tripoli allows to increase the extraction degree of silicon into the alloy at 1900°С to 82.5 %.To obtain FS45 grade ferrosilicon from tripoli, the following conditions are necessary: temperature of 1750 -1900°С, the presence of 37.8 -51 % of iron and 37 % of carbon.The electric smelting in an arc furnace allows producing FS50 grade ferrosilicon containing 51.1 % of silicon.