Thermochemical analysis of smelting of ferruginous manganese ore for silicomanganese production

Ferruginous manganese ores contain high concentrations of iron and having low Mn/Fe ratio and are not suitable to produce standard grade of silicomanganese. Thermochemical calculations based on available thermodynamics databases were used to understand the smelting behavior of the ore mix consisting of ferruginous manganese ore and slag from high carbon ferromanganese. A basicity map was constructed in terms of input burden material basicity B (= (CaO wt%+MgO wt%)/SiO2 wt%) and input R (= (CaO wt%+ MgO wt%)/Al2O3 wt%) value for estimating the optimum operating basicity window for low manganese and silicon partition ratio or high alloy recovery. Various experiments were conducted to check the maximum grade and recovery of the alloy based on the thermochemical equilibrium simulation study. The present study reveals usefulness of preliminary thermochemical calculations to facilitate process design and development of silicomanganese smelting using ore mix consisting of ferruginous manganese ore and slag from high carbon ferromanganese.