Recovery of ammonia and hydrogen fluoride from ammonium fluoride solutions.

摘要

A method of recovering hydrogen fluoride and ammonia from an aqueous ammonium fluoride solution is provided. Ammonia and water are evaporated from a mixed liquor having an aqueous phase and an organic phase. The aqueous phase of the mixed liquor has a total fluorine concentration of at least about 15 wt% and an ammonium fluoride molar fraction of at least about 0.67. The mixed liquor is formed by combining the aqueous ammonium fluoride solution with (i) an aqueous solution of ammonium fluoride and ammonium bifluoride; (ii)a strong amine extractant which is immiscible in the aqueous solution of ammonium fluoride and ammonium bifluoride; and (iii) water. The evaporation of ammonia and water from the mixed liquor causes the amine to become loaded with hydrogen fluoride. The HF-loaded amine is recovered from the mixed liquor and hydrogen fluoride is stripped therefrom in an amount sufficient to lower the HF:amine molar ratio by at least about 0.2.