中文摘要：

从理论上研究在盐水溶解平衡计算中，自由能最小化法与溶度积法的关系，并比较两种计算方法，二者计算结果完全一致。对于低四元的体系，溶度积法较为方便，而对更高元的体系，自由能最小化法有其优越之处。计算中，采用合适的算法至关重要。一维搜索法、插值法、多项式拟合求解法、坐标轮换法、MatLab求解最优化问题的函数等，均可以顺利实现盐一水溶解平衡的体系自由能最小化计算；对于溶度积法，二分法、弦截法、优选法、牛顿法、最速下降法、抛物线法及MatLab求解联立方程问题的函数等都很有效。

英文摘要：

The relationship between the minifying free energy and solubility product were studied for the calculation of the equilibrium of sah-water system. The research showed that the results of two methods were agreeable; for the system freedom degree of which was lower than four, the method of solubility product was more convenient; but for the system freedom degree of which was more than four, the method of the minifying free energy was more precise. In these methods, it was important that suitable algorithm was used. One dimensional search method, interpolation method, polynomial-fitting method, variable rotating method and MatLab were effective for the minlfying free energy; dichotomy method, secant method, optimal method, Newton method, steepest descent method and parabolic method were effective for the method of solubility product.