铬酸钾-碳酸钾高效分离研究 Ⅰ.相图分析与溶解度计算

Study on the effective separation of potassium chromate and potassium carbonateⅠ.Phase diagram analysis and solubility calculation

铬酸钾-碳酸钾的高效分离是铬盐清洁工艺亚熔盐介质再生的重要环节。据K2CrO4-K2CO3-H2O体系溶解度分析,蒸发结晶是该分离过程控制的关键,对此进行了详细的相图分析。选用Pitzer模型的HW公式,以二元电解质溶液的Pitzer参数推算了100℃时K2CrO4-K2CO3-H2O体系相平衡情况,理论计算结果与实验结果吻合较好,最大相对误差为16.26%,平均相对误差为7.39%。

The effective separation of potassium chromate and potassium carbonate is of great importance for the regeneration of the Sub-Mohen Salt （SMS） media in the new cleaner production technol- ogy of chromate. According to the analysis on the solubility data of the K2CO3-K2CrO4-H2O system, evaporating crystallization is a key step to separate potassium chromate from potassium carbonate solution. The phase diagram analysis was carried out in detail. Using the binarysystem coefficients of the related electrolytes, the phase equilibria of the K2CO3-K2CrO4-H2O system at 100 ℃ redicted by Pitzer＇s model modified by Harvie and Wear, and the predicted results were in good agreement with the experimental results with the maximal relative error of 16.26 % and average error of 7.39 %.