| abstract |
The present invention relates to a method of recovering calcium fluoride as a raw material for hydrogen fluoride production from a by-product mixed salt containing sodium fluoride and / or potassium fluoride, purifying the same, and reusing the same. Alternatively, fluorine in a by-product mixed salt containing potassium fluoride is reacted with a calcium compound to recover calcium fluoride, and further reacted with fluoride to further increase the purity, and reused as a raw material for producing hydrogen fluoride. [Selection diagram] None |