Production of Fe-Si-Mn from leached sea nodule residue

A pilot plant for processing of polymetallic sea nodule on 500 Kg/day scale has been set up by Department of Ocean Development at CRDL, HZL, Udaipur. After recovery of Cu, Ni & Co by NH3/SO2 pressure leaching, the generated residue contains considerable amount of manganese and iron. Attempts on recovery of manganese from this residue has been made at National Metallurgical Laboratory and standard grade Fe-Si-Mn alloy has been produced. Two different routes of smelting were carried out which comprised single stage smelting of residue blended with manganese containing materials and two stage smelting of residue with out any blending. The process is developed at 20 Kg scale and has been tested at 300 Kg scale in pilot plant also. A maximum recovery of Mn in the form of Fe-Si-Mn alloy has been found 68.0%