The present work investigates the solubility of dipotassium and monopotassium phosphate in near- and supercritical water. The highest solubilities exceeded 100 mmol kg⁻¹ at 633.15 K and 30 MPa, the lowest temperature and highest pressure conditions examined, while at 723.15 K and 19 MPa, the lowest solubilities were observed for approximately 0.2 mmol kg⁻¹and 0.001 mmol kg⁻¹. For potassium phosphates, increasing density and decreasing temperature monotonically increased their solubility. Three semi-empirical models were employed to correlate the measured solubility data. Enthalpy model and ionization model were demonstrated to provide the highest accuracies for correlating the experimental solubility of di- and monopotassium phosphate, respectively. The chemical equilibrium reactions facilitating the dissolution and precipitation of potassium phosphates were assessed by theoretical calculations via R-HKF equations of state. Calculations by the R-HKF EOS indicated that precipitation was thermodynamically favored under all conditions, however, increasing temperature and water density promoted the dissolution and hydrolysis of potassium phosphates.

目前的工作研究了磷酸二钾和磷酸一钾在近临界和超临界水中的溶解度。在 633.15 K 和 30 MPa（所检查的最低温度和最高压力条件）下，最高溶解度超过 100 mmol kg ^-1，而在 723.15 K 和 19 MPa 下，观察到最低溶解度约为 0.2 mmol kg ^-1和 0.001 mmol kg ^{- 1}. 对于磷酸钾，增加密度和降低温度会单调增加它们的溶解度。三个半经验模型被用来关联测量的溶解度数据。焓模型和电离模型分别为关联磷酸二钾和磷酸二氢钾的实验溶解度提供最高准确度。通过 R-HKF 状态方程的理论计算来评估促进磷酸钾溶解和沉淀的化学平衡反应。R-HKF EOS 的计算表明，在所有条件下，沉淀在热力学上都是有利的，然而，温度和水密度的增加促进了磷酸钾的溶解和水解。