Nickel, Cobalt and Copper Recovery from Sea Nodules by Direct Smelting Process

A direct smelting process has been developed at CSIR-National Metallurgical Laboratory, to recover all four valuable metals such as Ni, Co, Cu and Mn. Initially sea nodules containing 1.1% Cu, 1.15% Ni, 0.76% Co, 22.3% Mn, 5.5% Fe and 13.1% SiO2 was smelted in presence of coke to produce an alloy rich in Ni, Co, Cu and Fe. Various parameters such as amount of coke, quartz, smelting temperature and holding time etc. were optimized on different scale between 0.5–20 kg scale. Under optimized condition, the alloy of composition: 16.% Cu, 18.4% Ni, 1.2% Co 57.0%) Fe and 3.6% Mn was produced on 20 kg scale using 7% coke with more than 90% metal recovery. The process was further up-scaled to 250 kg where similar recovery was achieved with 8% coke and 1 h holding time. The alloy and slag was further processed to recover different value added products.