Abstract: Lithium hexafluorophosphate manufacturing enterprises produce large amount of mixed acid,which mainly contians fluorine hydride and chlorine hydride.A technology for preparation of calcium fluoride and by-product hydrochloric acid with fluorine-containing mixed acid by-produced from lithium hexafluorophosphate manufacturing enterprises and calcium chloride as raw materials was introduced.Optimum process conditions were investigated and confirmed as follows:reaction temperature of 60 ℃,mass fraction of calcium chloride solution of 50%,adding calcium chloride solution and mixed acid by two-way method(i.e.take 20% of mixed acid to be added into the reactor as the bottom liquid,add the calcium chloride solution and remained mixed acid into the reactor at the same time with a certain speed).Optimum process conditions were also verified by tests.Quality of calcium fluoride product met the first grade requirement of enterprise standard and the by-produced hydrochloric acid′s mass fraction reached more than 25%.This process is simple and production is easy to control.

Key words: fluorine-containing mixed acid, calcium fluoride, hydrochloric acid, fluorine hydride