Smelting Process of Chromite Ore Fines to Produce Crude Fe–Cr–Ni–N Alloy

Abstract

The smelting behavior of waste chromite ore fines containing Cr and Ni to produce crude Fe–Cr–Ni–N alloy was investigated in this study. In the experiments, for each heat, liquid steel melt (metal pool 1 kg) was prepared in a 3--capacity laboratory-scale electric arc furnace for the absorption of reduced metals like chromium, nickel, etc., under hydrogen and nitrogen plasma atmosphere at ~ 1600 °C temperature. The result shows the formation of crude alloy containing ~ 13% Cr, ~ 3% Ni along with ~ 500 ppm nitrogen. The highest recovery level of chromium was achieved ~ 63% in 20-min nitrogen plasma exposure. A negligible amount of chromium recovery (14.73%) in case of only hydrogen plasma and improved recovery (60%) for a combination of carbon and hydrogen plasma was observed. Suitable nitrogen level in the Fe–Cr melt can replace the required nickel content for making austenitic stainless steel. Hence, smelting reduction of chromite ore fines in the plasma arc furnace could be feasible to produce crude Fe–Cr–Ni–N alloy. This alloy could be used for making austenitic stainless steel after adopting suitable decarburization techniques. © 2020, The Indian Institute of Metals - IIM.