Solubility of Calcium Sulphate in the Binary NaCl-H2O and Ternary NaCl-MgSO4-H2O Systems

Central Salt & Marine Chemicals Research Institute, Bhavnagar-364 002

Manuscript received 16 November 1995, revised 19 August 1996, accept.ed 3 January 1997

The solubility of calcium sulphate in different concentrations of sodium chloride and magnesium sulphate have been determined at 25, 35 and 100º. The calcium sulphate occurs as its dehydrate at lower temperatures bot at higher temperatures as its anhydrate in the solid phase. The study has been extended to the solubility of calcium sulphate in the system NaCI-H₂O and NaCI-MgSO₄-H₂O. Further, it has been applied to interpret the solubility of calcium sulphate with increasing density of sea water brine and underground brines in view of the multi-ions occurring in them.