Extn. of nickel and other metals - from manganese nodules obtd. from ocean bed, using ammonium bisulphate and sulphur dioxide leach

摘要

In the extn. of metals from ores such as manganese nodules found on ocean beds, the milled ore is neutralised by acidified water and leached by NH4HSO4 with stirring at pH 1-3, the solid phase being removed and the liq. treated with NH3 to ppte. metallic impurities, the valuable metals being obtd. from the soln. by solvent extn. MnCO3 is ppte. from the residual soln. by injecting CO2, air and NH3, and the filtrate is conc. by evapn. to crystallise (NH4)2SO4 which is heated in a furnace to obtain NH4HSO4 and NH3, both being recycled for leaching, pptn. and pH adjustment. The NH4HSO4 leach is pref. accompanied by the controlled injection of SO2 for recovering part of the Mn and improving the dissolution of Ni and Cu. The winning of Ni, Cu, co and Ti by a simple, economic process is provided.