湖北某化工公司将磷酸生产过程中的废水及磷石膏固结排出的渗水进行收集并循环利用,冬天废水中的无机盐类结晶堵塞泵体和输送管道,影响废水循环利用系统的正常运行。经分析结晶物主要成分是氟硅酸钾等难溶盐。采用平衡法测量了0~40 ℃内,氟硅酸钾在pH为1.5~3.5时稀硫酸溶液中的平衡溶解度,并采用Apelblat经验方程对氟硅酸钾平衡溶解度与温度做了关联,为废水中氟硅酸钾等难溶盐的结晶动力学研究提供了基础物性数据。研究结果表明：1）随着pH的降低或温度的升高,氟硅酸钾的溶解度增加;2）Apelblat经验溶解度方程能较好地关联氟硅酸钾平衡溶解度与温度。

The wastewater in the process of phosphoric acid production and the seepage water from the consolidation of phos-phogypsum were recycled by a chemical company in Hubei province.Crystallization of the inorganic salt in the wastewater in winter may block the pump body and the transportation pipeline,which has a great effect on cyclic utilization ratio of the wastewater.The component analysis results showed that the crystals were mainly composed of insoluble salts such as potassium fluosilicate.The equilibrium solubility of potassium fluorosilicate in dilute sulfuric acid solution with pH of 1.5~3.5 was measured by the equilibrium method in the temperature ranges of 0~40 ℃,and the equilibrium solubility of potassium fluorosilicate was correlated with temperature by Apelblat empirical equation,which provided basic physical data for studying the crystallization kinetics of insoluble salts such as potassium fluorosilicate in wastewater.Results showed that the solubility of potassium fluorosilicate increased with the increased environment temperature or decreased pH,and Apelblat empirical solubility equation was well correlated with the equilibrium solubility and temperature of potassium fluorosilicate.