COPPER-EXTRACTION FROM CHLORIDE SOLUTIONS BY EVAPORATION AND REDUCTION WITH HYDROGEN

In order to obtain a metallic product from the CuCl2-HCl solution puri fied by anion-exchange separation, the straightforward method of evapo ration to dryness and reduction with H-2 was investigated. Thermodynam ic study of the probable reactions in the Cu-Cl-H-O system pointed out the feasibility of the direct reduction of CuCl2. In order to find ou t the practical reduction rates and effective recoveries, the process was tested under different conditions. The first step of reduction, wh ich results in the conversion of CuCl2 to CuCl, is readily executable at temperatures slightly below the CuCl-CuCl2 eutectic point. The seco nd step, which results in the metallic product, requires higher temper atures, though safely below the melting point of CuCl. Kinetic analysi s of the critical second step provided an activation energy of 138 kJ mol(-1) which could be interpreted in terms of a chemical reaction dom inated mixed mechanism.