Sulfurization of Fe-Ni-Cu-Co Alloy to Matte Phase by Carbothermic Reduction of Calcium Sulfate

摘要: Calcium sulfate (CaSO4) is proposed as an alternative sulfur source to convert the Fe-Ni-Cu-Co alloy matte phase. Solid carbon was used a reducing agent and influence of oxide fluxes on sulfurization efficiency at 1673 K (1400 °C) in CO-CO2-SO2-Ar atmosphere investigated. When CaSO4 equilibrated with without any agent, it reduced by Fe liquid alloy, resulting formation FeS. The about 56 pct, even though excess amount (gypsum equivalent, G eq = 1.7) added. Adding solid significantly shortened equilibration time from 36 3.5 hours increased 91 lower than theoretical equivalent for carbothermic reduction CaSO4, viz. C eq = 0.7. Although CaS (not FeS) formed primary reaction product, continuously reacted forming CaO-rich slag. Neither nor were affected addition Al2O3 (-SiO2) fluxes, but fell 2.5 Al2O3-Fe2O3 flux because former systems produced primarily calcium silicate aluminate, which have relatively high melting points, whereas latter system ferrite, has point. Consequently, (waste gypsum) can replace expensive pure raw material small amounts iron (Fe2O3) material. present results be improve recovery rare metals, such Ni Co, deep sea manganese nodules.