多元轻稀土硝酸盐水溶液的等压实验研究

Isopiestic Experiment Studies on Multi-component Light Rare Earth Nitrate Aqueous Solutions

采用改进的等压法研究了影响多元轻稀土硝酸盐水溶液体系等压平衡的因素,确定了在低水活度区以氯化钙水溶液、高水活度以氯化钠水溶液为等压平衡参考物;等压平衡实验时间按水溶液浓度由高到低的顺序依次从4d到7d不等;确定了硝酸镧、硝酸镨及硝酸钕水溶液的等当点。结果表明,在实验误差允许范围内,所考察的系统符合偏理想溶液模型。

The factors for affecting isopiestic equilibrations of multi-component light rare earth nitrate aqueous solutions were studied by a modified isopiestic technique. The results showed that sodium chloride should be taken as a reference solution while the water activity was higher and calcium chloride should be taken as a reference solution if the water activity was lower. The isopiestic equilibrations time was 4d to 7d in turn according to the solution concentration. The equivalent points of lanthanum nitrate,praseodymium nitrate and neodymium nitrate aqueous solutions were determined,respectively. The results fitted the partial ideal solution model within experimental uncertainties.