Measurements of Mineral Solubilities in the Quaternary System KCl-MgCl2-ZnCl2-H2O at 323 K

In the process of mineralization and the extraction, the solubilities of metal minerals are affected by chlorides of alkali and alkaline earth metals, such as NaCl, KCl, MgCl2 and CaCl2, the studies on solubilities of chloride minerals in solutions are of significance for the separation and enrichment of elements in hydrometallurgy. To study the solubility relationships of minerals (such as KCl, MgCl2 and ZnCl2) in aqueous solutions, the phase equilibria of the quaternary system KCl-MgCl2-ZnCl2-H2O at 323 K were investigated by means of the isothermal dissolution equilibrium method. These investigations were carried out and the mineral solubilities were measured. The dry salt phase diagram and water content diagram were plotted and there are three double salts formations of MgZnCl4 center dot 6H(2)O, KMgCl3 center dot 6H(2)O (Car) and 2KCl center dot ZnCl2. The dry salt phase diagram contains four invariant points and nine isothermal solubility curves, which divide the phase diagram into six crystallization regions, and the crystallization regions correspond to the existence of six equilibrium solid phases, namely ZnCl2, 2KCl center dot ZnCl2, MgZnCl4 center dot 6H(2)O, MgCl2 center dot 6H(2)O (Bis), Car and KCl. The crystallization zone of KCl is the largest, and those of ZnCl2 and MgCl2 center dot 6H(2)O are the smallest. In addition, the equilibrium solid phases at the invariant points of ternary subsystems at 323 K and 373 K were compared and discussed.

Automated summary

Studying the solubilities of chloride minerals in aqueous solutions is crucial for the separation and enrichment of elements in hydrometallurgy. Investigations of the phase equilibria of the quaternary system KCl-MgCl2-ZnCl2-H2O at 323 K revealed the formation of various double salts. The resulting dry salt phase diagram divided into six crystallization regions, providing insights into the equilibrium solid phases as well as the comparison of ternary subsystems at different temperatures.