METHOD OF RECOVERING AND PURIFYING CALCIUM FLUORIDE FROM BYPRODUCT SALT MIXTURE CONTAINING FLUORINE

摘要

PROBLEM TO BE SOLVED: To provide an effective method by which fluorine is recovered at high recovery rate as calcium fluoride from a byproduct salt mixture produced from the reduction process of metal tantalum and/or metal niobium and after impurities are remarkably reduced, calcium fluoride is recycled as a raw material of hydrogen fluoride. SOLUTION: Fluorine in the byproduct salt mixture containing sodium fluoride and/or potassium fluoride is reacted with a calcium compound to be recovered as calcium fluoride. The reaction of the fluoride is advanced further to increase the purity of calcium fluoride and the calcium fluoride is used as the raw material for the production of hydrogen fluoride. COPYRIGHT: (C)2004,JPO