硫酸钙在Ca-Mg-K-Cl-H_2O体系转化过程中溶解度研究

脱硫石膏常压盐溶液法转化生成α-半水石膏是实现脱硫石膏综合应用的有效途径,文章着重研究了该转化过程中不同种类和浓度的盐溶液对硫酸钙溶解度的影响,以此作为脱硫石膏转晶的重要参数。实验过程中,硫酸钙溶解度测定采用溶解平衡法,结果表明温度、盐的种类及浓度对硫酸钙溶解度影响最为显著。在CaCl2溶液中,由于同离子效应的影响,CaSO·42H2O溶解度随着盐浓度的增加而降低;在MgCl2溶液中,低于4%浓度时CaSO·42H2O溶解度随着盐浓度的增加而逐渐升高,高于4%浓度时溶解度随温度和浓度的变化不明显;在KCl溶液中,CaSO·42H2O溶解度变化总体趋势是随着盐溶液浓度增加而升高。在混合盐溶液中,随浓度增加CaSO·42H2O溶解度有很明显的下降趋势,表明同离子效应影响最显著。

Calcium Sulfate Solubilities in the Ca-Mg-K-Cl-H2O System of Transformation Process

Flue gas desulphurisation(FGD) could transform to hemihydrate gypsum in salt solution at atmospheric pressure. It is an effective way to realize FGD resource utilization. This article focus on the solubility of gypsum in different types and concentrations of salt solution in the transformation processes, as an important parameter in FGD crystal transformatioa In the experimental process, solubility of calcium sulfate was determined by dissolved balance method. Experimental results shows that the solid calcium sulfate could achieve dissolution equilibriumsalt in 4 hours. The temperature, salt type and concentration has a significant impact on the solubility. In CaCl2 solution, as a result of the existence of the same ion effect, with the increase of salt concentration the solubility of CaSO4·2H2O decreased. In MgCl2 solution, when the concentration less than 4%, with the increase of salt concentration the solubility of CaSO4·2H2O increased, while higher than 4%, the solubility of CaSO4·2H2O was not obvious with the concentration increasing. In the KC1 solution, the general trend is that the solubility of CaSO4·2H2O increased with the concentration increasing. In the mixed salt solution, the solubility of CaSO4·2H2O reduced with the concentration increasing, it shows that the same ion effect has the most effect.