冰晶石母液的综合利用

Comprehensive utilization of cryolite mother liquor

多氟多化工股份有限公司生产冰晶石采用两种方法,即黏土-盐卤法和氟硅酸钠法。黏土-盐卤法产生大量酸性母液,氟硅酸钠法产生大量碱性母液,两种母液中都含有对氟化盐生产有用的氟和钠。黏土-盐卤法生产冰晶石,其原料工业盐中氯化钙含量高,使得冰晶石中氧化钙含量超标。提出了冰晶石母液综合利用的方法,即将酸性母液与碱性母液混合,用于溶解工业盐,利用混合液里的氟离子和氢氧根把工业盐中的氯化钙转化成氟化钙和氢氧化钙除去,再用精制盐水代替地下水,用于稀释冰晶石母液,从而达到回用废液的目的。经过实验室试验和中间试验,证明该方法效果良好,不仅回收了废液中的有用成分,而且使黏土-盐卤法生产的冰晶石产品中氧化钙含量大大降低。

There are two methods, namely clay-bittern method and sodium fluosilicate method, being applied in Do-fluoride Chemicals Co. ,Ltd to produce cryolite. Clay-bittern method produces massive acidic mother liquor and sodium fluosilicate method makes large amount of alkali mother liquor,in both of which there are useful fluorine and sodium ingredients for fluoride production. In production of cryolite by clay-bittern method, calcium chloride content in its raw material （ i. e. industry salt）is high,which causes calcium oxide content in cryolite exceed the allowed figure. A comprehensive utilization method for cryolite mother liquors has been proposed, namely mix acidic mother liquor with alkali one, use the mixture to dissolve industry salt, remove calcium chloride by turning it into calcium fluoride and calcium hydoxide through the fluorine ions and hydroxid radicals in the mixture, and then use the purified salt water to replace primary water for diluting cryolite mother liquor, thus achieve the goal of reusing waste liquor. After the laboratory and pilot tests,effect of this method is good, not only has recycled the useful ingredients in waste liquor, but also greatly reduces calcium oxide content in cyrolite product produced by clay-bittern method.