HYDROLYSIS OF ZINC-CHLORIDE IN AQUEOUS AMMONIACAL AMMONIUM-CHLORIDE SOLUTIONS

Zinc solubility in the ZnCl2-NH4Cl-NH3-H2O system for chloride concent rations lower than 5 m in the temperature range 30-50 degrees C was st udied. The experimental results show that, for chloride concentrations between 3.5 and 5.0 m, the zinc solubility is determined by the solub ility of the zinc diammine chloride. For chloride concentrations lower than 3.0 m, there are two zinc compounds, the hydroxide Zn(OH)(2) and the hydroxychloride Zn(OH)(1.6)Cl-0.4, on which the solubility of zin c depends, according to the value of the ratio [NH3](Total)/[Zn](Total ).