混合电解质水溶液固液平衡计算

用Lu-Maurer活度系数模型在不增加任何模型参数的前提下回归出18种晶体的溶度积,在此基础上预测了H~+、Mg~(2+)、K~+、Na~+、NH_4~+、Ca~(2+)、Cl~-、SO_4~(2-)、NO_3~-等离子所组合的13种体系在不同温度(最低温度为273.15 K,最高温度为378.15 K)及最高离子强度为34.55 mol·kg~(-1)下的固液平衡.预测结果较为满意.从而说明了该模型的良好普适性和可靠的温度外推性.可以为工业结晶过程提供相平衡的预测估计.

CALCULATION OF SOLID-LIQUID EQUILIBRIA FOR MIXED AQUEOUS ELECTROLYTE SOLUTIONS

In the present study the Lu-Maurer model (1993,1996)for aqueous electrolyte solutions was used to correlate solubility products Ksp of 18 salts including MgSO4, KCaCl3, NH4NO3, MgSO4·H2O, MgSO4·4H2O,MgSO4·5H2O,MgSO4·6H20,MgSO4·7H2O,CaCL2·2H2O,CaCL2-4H2O, CaCl2·6H2O,KMgCl3·6H2O,KaCaCl4·2H2O, CaMg2Cl6·12H2O, K2Mg2(SO4)3, K2Mg(SO4)2·2H2O, K2Mg(SO4)2·4H2O and K2Mg(SO4)2·6H2O. With no additional parameters this model was used to predict solubilities of 13 systems including MgCl2-CaCl2-H2O, KCl-HCl-H20, NaCl-HCl-H20, NH4Cl-HCl-H20,CaCl2-KCl-H20,MgCl2-KCl-H20,CaCl2-NaCl-H20,MgCl2-NaCl-H20,MgS04-K2S04-H20, NH4N03-NH4C1-H2o, NaNO3-NH4NO3-H2O, NaCl-KCl-MgCl2-H2O and NaCl-KCl-CaCl2-H2O in the temperature range from 273.15 K to 378.15 K. It was shown that this model is capable of predicting solubilities in mixed electrolyte aqueous solutions at elevated temperatures and up to very high ionic strength. It could be used to predict the composition of solid liquid phase equilibria for determining the technical conditions for the separation and manufacture of the interest inorganic salts.