Thermodynamic equilibrium of CaSO4-Ca（OH）2-H2O system

• Published in: Transactions of Nonferrous Metals Society of China Vol. 19; no. 1; pp. 249 - 252
• Main Author: 彭小玉 王云燕 柴立元 舒余德
• Format: Journal Article
• Language: English
• Published: 2009
• Subjects: CaSO4-Ca（OH）2-H2O; 热处理; 金属表面处理
• ISSN: 1003-6326

The pc-pH diagrams of the CaSO4-Ca（OH）2-H2O system and its two subsystems at 298.15 K were constructed according to the theory of thermodynamic equilibrium. The interaction characteristics between the solubility of CaSO4（s） and Ca（OH）2（s） can be found out from the diagrams. CaSO4（s）, Ca（OH）2（s） and solution coexist when the pH value of solution is about 13.2. CaSO4（s） with the minimum solubility of 0.411 g/L is in equilibrium with solution when the pH value is lower than 13.2, and Ca（OH）z（S） with the minimum solubility of 2.749 g/L is in equilibrium with solution at the pH value over 13.2, which provides a theoretical basis for the treatment and reuse of industrial wastewater, especially for the wastewater containing sulfate which can be treated by lime-milk neutralization.