磷石膏一步法制取硫酸钾工艺研究

磷石膏是磷酸及其盐的主要副产物,其处理方法多数是堆积放置,从而造成占用大量土地资源,同时还造成了污染。目前,硫酸钾生产主要以曼海姆法为主,即用浓硫酸与氯化钾反应。其主要缺点是设备投资高,腐蚀严重,生产成本高。以副产物磷石膏为主要原料生产硫酸钾,达到了克服上述缺点,避免土地资源浪费和环境污染之目的。磷石膏在助溶剂乙二胺四乙酸存在下,在混合溶剂甲醇和水中与氯化钾反应,生成硫酸钾析出。反应条件为：温度25℃,液固比25,助溶剂浓度为15％,甲醇与水之比为1∶1,反应时间1．5h,磷石膏用量为理论量的110％。产品经检测达到ZBG21006-89一等品指标。

Study on the new process of producing potassium sulfate from phosphogypsum by one-step technology

As the main by-product of the phosphoric acid and its salt, it's generally put in stacks. As a result, quantities of field was occupied, and pollution was caused as well. So far, potassium sulfate has been produced mainly by the reaction of concentrated sulfuric acid and potassium chloride. Its main disadvantage is high equipment investment, serious corrosion and high costs. In this article, phosphogypsum, the by-product are used as the main materials to produce potassium sulfate, so it can overcome the weakness of the above method, also can avoid the waste of field and environmental pollution. The procedure is as following. As the cosolvent of ethylenediamine tetraaetic acid exists, phosphogypsum will reacts with potassium chloride in the mixed solvent of alcohol to water, then the potassium sulfate will be separated out. The reaction condition are:the temperature is 25℃, the proportion of liquid to solid is 25, the concentration of co-solvent is 15% ,the ratio of alcohol to water is 1:1, the reaction time is 1.5 h, the dosage of phosphogypsum is 110% of its thoretical usage. After detection the product can meet the standard of ZBG21006-89.