铬酸钾-碳酸钾高效分离研究Ⅱ.结晶工艺实验研究

Study on the effective separation of potassium chromate and potassium carbonate Ⅱ. Experimental investigation on the crystallization process

针对铬酸钾碳化法生产重铬酸钾母液利用过程,研究了K2CO3-K2CrO4-H2O体系蒸发-冷却结晶过程工艺条件。发现控制过饱和度的产生速率是过程控制的关键,少量铝、硅杂质的存在会在一定程度上抑制成核。铬酸钾的回收率可达95%以上,实现了碳酸钾与铬酸钾的高效分离。

The optimum evaporating-cooling crystallization process conditions were studied for the separation of potassium chromate from the K2CO3-K2CrO1-H20 system for the cleaner production of potassium dichromate from potassium chromate by using carbon dioxide as the acidifying agent. The experimental results showed that the control of the supersaturation level during evaporation was of significance and the small amount of silicon and aluminum remained in the system suppressed the nucleation of K2CrO4 to some extent. A remarkably high removal rate of more than 95% was achieved for potassium chromate, and therefore the effective separation of potassium chromate and potassium carbonate was achieved before the regeneration of the Sub-Molten Salt （SMS） media.