Extraction of antimony and niobium with tributyl phosphate from fluoride-ammonium solutions

摘要

The purification of niobium from antimony impurity via extraction with tributyl phosphate from solutions of the HF + NH4F mixture has been studied. It has been established that at an HF + NH4F content equal to 7-16 mol/L and an NH4F concentration of 30% in the mixture, Sb extraction hardly changes (70-80% for one stage), and Nb coextraction abruptly decreases to values of less than 0.5%.