三元体系NaBr-Na_2SO_4-H_2O和KBr-K_2SO_4-H_2O 398K相平衡研究

Phase Equilibria of NaBr-Na_2SO_4-H_2O and KBr-K_2SO_4-H_2O Ternary Systems at 398 K

采用等温溶解平衡法研究了三元体系NaBr-Na_2SO_4-H_2O和KBr-K_2SO_4-H_2O在高温398 K的相平衡关系,测定了398 K条件下平衡溶液的溶解度。研究发现:两个三元体系均为简单共饱和型,无复盐及固溶体生成。根据溶解度数据绘制了相图,相图中均有一个共饱和点,2个平衡固相结晶区和2条单变量曲线。三元体系NaBr-Na_2SO_4-H_2O所对应的平衡固相为NaBr和Na_2SO_4;KBr-K_2SO_4-H_2O体系对应的平衡固相为KBr和K_2SO_4。对比了上述两个三元体系在不同温度条件下共饱点的液相组成,实验结果表明,NaBr和KBr分别对Na_2SO_4和K_2SO_4有较强的盐析作用。

Phase equilibria of NaBr-Na2SO4-H2O and KBr-KzSO4-H2O temary systems at 398 K were studied by an isothermal solution saturation method. The solubilities of these systems were determined. The results show that the two systems are both of simple type with no complex salts or solid solutions formed. Both phase diagrams show one eutectic point, two univariant curves and two crystallization regions. The solid phase in NaBr-Na2SOa-H2O is composited of sodium bromide（NaBr） and sodium sulfate（Na2SO4）, and the solid phase in KBr- K2SOa-H2O is composited of sodium bromide（KBr） and sodium sulfate（K2SO4）. The liquid components of the ternary systems at invariant points were compared at different temperatures. The results show that NaBr and KBr have better salting-out effects on Na2SO4 and K2SO4, respectively.