Direct production of Fe-Cr-Ni-Mn crude alloy from the mine waste by arc smelting process

ABSTRACT The utilisation of mine waste/low-grade ores has become a major concern for the mining and metallurgical industries. Day by day, high-grade ores are rapidly depleted and fines/low-grade ores are dumped in the mining site, becoming a source of pollution and taking up a lot of area. To overcome the above problem, a novel smelting reduction technology was directly used to utilise low-grade/mine waste as an alternative raw material for the production of crude alloy and further for stainless steel. In this work, Fe-Cr-Ni-Mn crude alloy was directly produced from the mine waste/ low-grade ores by a high-temperature arc smelting process. The dried composite pellets were prepared using chromite overburden (COB), chrome ore fines (Cr ore fines), and lean-grade manganese ore (LG-Mn ore) in the ratio 4:3:3 at a 500 g scale. The effect of slag basicity (0.1–0.8) on metal concentration and recovery was studied and optimised for maximum metal recovery (Fe, Cr, Ni, and Mn) in the direct smelting experiments. The Fe-Cr-Ni-Mn crude alloy having 71.6% Fe, 22.69% Cr, 1.02% Ni, 0.972% Mn, and 2.41% C at 0.4 basicity was successfully produced with a metal recovery of 63.1% at ∼1700°C. GRAPHICAL ABSTRACT