Reduction roasting of deep sea manganese nodules using liquid and gaseous reductants

National Metallurgical Laboratory has developed a reduction roast-ammonia leach-solvent extraction-electrowinning process operational at pilot scale for the recovery of Cu, Ni and Co from sea nodules of Central Indian Ocean. This paper describes the effect of the various process parameters in reduction roasting on the leach recoveries of Cu, Ni and Co with the use of both liquid and gaseous reductants. For this purpose, reduction roasting experiments on sea nodules has been carried out at laboratory scale. Leach recoveries in excess of 95% for Cu & Ni and 75% for Co could be achieved under optimum conditions with both liquid and gaseous reductants