INTENSIFICATION OF REDUCTION OF OXIDE NICKEL ORES

摘要

Laboratory studies into reduction of oxide nickel ores with cast iron in sparged melt were carried out in crucibles at 1500 C. Argon blowing at a rate of 0.9 to 1.1 m3/m2s through a vertical lance submerged into the melt down to the iron/ore interface permitted production of discard slag with 0.03% to 0.05% Ni and 0.01 Co. Bench-scale investigations of metallothermic reduction of oxide nickel ores were carried out in a plasma-arc furnace in intermittent mode. Ore containing 1.0% Ni and 0.08% Co was fed to the furnace along with 15% of calcium oxide as fluxing agent. Coke fines were fed onto the melt surface at a rate of 1% of the weight of the ore to reduce iron in the ore to wuestite and prevent "boiling-up" of the melt. The ferronickel obtained contained 15.2%Ni, 1.75% Co, 0.35% Si and 0.43% Cr. The nickel and cobalt contents in "discard" slags after blowing were on average 0.045 and 0.015%, respectively. The reduction process can be intensified by changing the position of the blowing lances in the bath and the depth of their submersion. The nickel and cobalt contents of ferronickel can be increased by periodical carbonization of cast iron.