Studies of the Solubility of Copper, Zinc and Cobalt Sulphates in Ortophosphoric Acid at 30 and 80 °C

Abstract

The article presents the results of studying systems of copper sulfate, zinc sulfate, cobalt sulfate - phosphoric acid - water by the isothermal method at 30 and 80 °C. It has been established that copper sulfate at 30 °C does not interact with phosphoric acid and exists in the form of copper sulfate pentahydrate. At 80 °C, the isotherm has two branches of crystallization. The first corresponds to copper sulfate pentahydrate, and the second to the new compound CuSO₄∙CuHPO₄∙2H₂O. Zinc and cobalt sulfates in solutions of phosphoric acid change their hydration. At 30 °C, the isotherms have two crystallization branches corresponding to hexahydrates and monohydrates of zinc and cobalt sulfates. At 80 °C, one crystallization branch corresponding to monohydrates is observed in the systems.