An Improved Process for the Production of Low-Carbon Ferromanganese in the Electric Arc Furnace

摘要

Low-carbon ferromanganese (LC-FeMn) is an essential ingredient for making high-strength low-alloy steel and stainless steel. The conventional industrial-scale silicothermic method for the production of LC-FeMn comprises several energy intensive complex steps consuming about 2000 kWh/ton. We have attempted an improved silicothermic process, which is based on a single step smelting of optimized charge mix in the electric arc furnace. Thermochemical simulation of the smelting process by FactSage 6.4 showed significant effect of the charge mix basicity (B = CaO/SiO2) on manganese, iron, silicon and phosphorous distribution between the metal and slag. The optimum basicity was found to be 1.5 at the charge mix ratio i.e., Mn ore/lime/SiMn of 1:1:0.6 in the smelting tests. Under optimum conditions, the energy consumption was about 690 kWh/ton. This approach has potential benefits for the ferromanganese industry in terms of simpler and energy efficient process.