COEXTRACTION - SELECTIVE STRIPPING FOR THE RECOVERY OF NICKEL AND COPPER FROM THE LEACH LIQUOR OF OCEAN NODULES

Ferromanganese deep sea nodules of the Indian Ocean have recently been recognised as a potential source of metals like copper, nickel, cobal t and manganese. For the treatment of the sea nodules following the re duction roast-ammonia leach process, the leach liquor containing coppe r, nickel and cobalt was processed to separate and recover these metal s by solvent extraction (SX) using 25% LIX 64N in kerosene. Almost qua ntitative extraction of copper and nickel was realized in a continuous run. During nickel stripping, the small amount of copper in the nicke l solution was removed by incorporating a copper extraction step using 10% LM 64N in kerosene. The purified pregnant nickel electrolyte was electrowon in a non-diaphragm cell. Copper was similarly recovered by electrowinning (EW). A closed circuit of SX-EW was run to produce cath odes of nickel and copper with energy consumptions of 3.85 and 2.01 kW h/kg for the respective metals.