Les Sulfates Basiques Mixtes de Cuivre et de Zinc

The pure basic sulphates of copper and zinc obtained at 20°C by addition of soda to CuSO 4 and ZnSO 4 . solutions have the respective compositions Cu 4 (OH) 6 SO 4 (monoclinic symmetry) and 3 Zn(OH) 2 ·ZnSO 4 ·4 H 2 O (hexagonal symmetry with double layers). In mixed solutions (10 g Me ++ /l), the solid solution Cu 4‐x Zn x (OH) 6 SO 4 precipitates at the low zinc concentrations. The distribution curve shows a change of slope at 25% Zn at. (x = I). A transition zone caracterized by a continue modification of the structure and the hydration of the precipitate separates this compound from the tribasic sulphate of zinc saturated by copper (33% Cu at.). For this solid solution the substitution occurs in the hydroxide layers only. The distribution factor indicates a continue selectivity for copper in the different phases.