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.