Plasma Smelting of Iron Ore Fines Having High Silica Content

Abstract

A lot of ore fines are collected at iron ore mines. Till date no measure move is being made for usage of fines for extraction of metallic iron. Generally metallic iron is produced through BFO and DRI processes where particle/ore size and reductant is the most important factor considered for BF charge. The present piece of research work is aimed at use of iron ore fines for production of metallic iron. So there is a process adopted for increasing recovery called agglomeration, which includes pellets and sinter. A newly emerging technology i.e. plasma smelting process is adopted for reduction of iron ore fines. In this project Pellets of iron ore fines (60 % Fe), 8.4% carbon, 0.3%catalyst (containing Al 33%, Ca 20%, Si 5%, Mg 42%) was sintered at 1260 degree centigrade. It is charged to a 35 KW dc arc plasma furnace and smelted for different time lengths i.e. 7, 9 and 13min using argon and nitrogen, as plasma forming gas. The amount of recovery for all samples is measured. Maximum of 93.6 % recovery is achieved. It is observed that use of nitrogen as plasma forming gas increases the rate of recovery than that of argon plasma, due to high energy flux of nitrogen gas which increases the enthalpy due to its diatomicity. The X-ray diffraction analysis shows the presence of ferrite, iron carbide and ferrosilicon nitride phases in the smelted product. Variation of microstructure is observed with the samples. The hardness measurement of different phases on the sample ensured the presence of ferrite, iron carbide and ferrosilicon phases depending on smelting condition