Thermodynamic equilibrium diagram of CaCl2-Ca(OH)2-H2O system

The lg c-pH diagram of the CaCl2-Ca(OH)2-H2O system and its two subsystems at 298.15 K are constructed according to the theory of thermodynamic equilibrium.The interaction characteristics between the solubility of CaCl2 and Ca(OH)2 can be found out from the diagrams.CaCl2.6H2O(s),Ca(OH)2(s) and solution coexist when the pH value of solution is about 10.8.CaCl2 with the minimum solubility of 1 682.4 g/L is in equilibrium with solution when the pH value is lower than 9.4,and Ca(OH)2 with the minimum solubility of 2.749 g/L is in equilibrium with solution at the pH value over 12.1,which provides a theoretical basis for the treatment and reuse of calcium chloride mother liquor for collocating lime cream which is the precipitant in the process of synthesizing magnesium hydroxide.