A Chemical Model to Characterise the Dissolution of Sulfides in CuCl2 - CuCl- FeCl3 - FeCl2 - NaCl - HCl- H2O System: Cupric Chloride Leaching of Synthetic NiS

A chemical model has been developed to investigate the dissolution of sulphide minerals in brine solutions containing copper and iron chlorides. The model has been employed to study the dissolution .of synthetic NiS using different initial concentrations of Cu(II), Cu(I), Fe(III) and temperature. The speciation of copper with particular reference to the formation of hydroxy-chlorides as a function of total chloride and H+ has been computed. The model predictions are in agreement with experimental results. It has been found that addition of Fe(III) results in the maintenance of a high Cu(II)/Cu(I) ratio leading to enhanced rates of dissolution and suppresses the loss of Cu(II) due to the formation of hydroxyl-complexes.