磷石膏制备K_2SO_4与CaCl_2·2H_2O新工艺研究

Study on the preparation of K_2SO_4 and CaCl_2·2H_2O by phosphogypsum

通过试验室模拟亚熔盐技术,以磷石膏、(NH_4)_2CO_3、KCl制备K_2SO_4与Ca Cl_2·2H_2O,试验制得的K_2SO_4产品质量满足GB 20406—2006《农业用硫酸钾》一等品质量要求;Ca Cl_2·2H_2O产品质量满足GB/T 26520—2011《工业氯化钙》Ⅱ类质量要求。根据试验结果,进行了50 kt/a磷石膏制备K_2SO_4与Ca Cl_2·2H_2O产业化工艺设备流程设计和经济效益测算,磷石膏综合利用效益约为264元/t。利用生态循环工程学新理论,采用亚熔盐技术,在不需要消耗氨的条件下实现磷石膏中的钙、硫、硅等资源回收利用,并且利用K_2SO_4与KCl的价格差,进一步实现磷石膏资源利用的经济效益。

K2SO4 and CaCl2·2H2O were prepared by phosphogypsum through simulating the submolten salt technology in the labo-ratory.The quality of K2SO4 product met with the quality requirement of first grade product of the national standard of potassium sulfatefor agriculture （GB 20406-2006） and the quality of CaCl2·2H2O products met the quality requirements of the national standard for in-dustrial calcium chloride（GB/ T 26520-2011）. According to the experimental results, the process design and economic benefit of theindustrial process equipment of K2SO4 and CaCl2·2H2O were carried out.The comprehensive utilization benefit of phosphogypsum wasabout 264 yuan RMB per ton. By adopting a new theory of ecological circular engineering, using the submolten salt technology torecovercalcium, sulphur and silicon in phosphogypsum without ammonia consumption, and taking the price difference between K2SO4 and KClinto account, the study realized the economic benefits of the process of phosphorus gypsum resource further.