Extraction of nickel and copper from the ammoniacal leach solution of sea nodules by LIX 64N

Abstract

Studies on the extraction of nickel and copper from the ammoniacal ammonium carbonate solution were undertaken using LIX 64N as an extractant. The solvent showed preference for extraction of copper over nickel from the ammoniacal solutions. The leach liquor of sea nodules from the Indian Ocean was processed in a laboratory-size mixer-settler unit by coextracting nickel and copper in 20% LIX 64N in kerosene. The extracted ammonia from the. solvent was removed by scrubbing with ammonium bicarbonate and dilute sulfuric acid. 'Nickel was selectively stripped with the spent electrolyte of 1.75 pH, and the strip solution was purified with a stream of LIX 64N to remove the residual copper. Copper was subsequently stripped with spent electrolyte containing 170.5 g/L sulfuric acid. These strip solutions were found to have an appropriate amount of acid for electrowinning the metals.