Calculation of phase equilibria in water-salt systems simulating the natural carbonate brines

Thermodynamic calculations of solubility diagrams were carried out for four -component systems with a common ion and four-component reciprocal water-sa lt systems containing sodium and potassium chlorides, sulfates, carbonates, and hydrocarbonates at temperatures from -5 degreesC to + 35 degreesC. Fit ter's equations were used to approximate the variations of excess thermodyn amic functions with solution composition. The calculation results are well consistent with experimental solubility data and can be used to simulate sa lt crystallization in the evaporative basins with the carbonate type of wat er.