An experimental study on the solubility of copper bichloride in water vapor

Using the solubility method, the solubility of CuCl2 in liquid-undersaturated HCl-bearing water vapor was investigated experimentally at temperatures of 330–370°C and pressures of 4.2–10 MPa. The results have shown that hydration could significantly enhance copper solubility and the concentrations of copper were positively correlated with $P_{H_2 O} $ . The solubility of copper in vapor phase increased with increasing $P_{H_2 O} $ at the constant temperature. CuCl2 was transported as hydrated species CuCl2(H2O)n gas in water vapor. The formation of complexes is proposed to be the result of the following reaction: $$CuCl_2^{solid} + nH_2 O^{gas} = CuCl_2 (H_2 O)_n^{gas} $$ The hydration number n decreased slightly with increasing temperature. Statistical hydration numbers are 4.0, 3.6 and 3.3 at 330, 350 and 370°C, respectively.