Purification of niobium from antimony by the extraction with tributylphosphate

The effect of the concentrations of HF and H2SO4 and organic-to-aqueous phase ratio V o : V aq on the distribution of Sb and Nb in their extraction with tributyl phosphate has been studied. It has been determined that, under the best conditions (HFfree 150 g/L, H2SO4 100 g/L, and V o : V aq = 0.3 : 1), and the extraction of Sb within one step is 72%, which is followed by the coextraction of Nb at 25%. The flow diagram of extraction and separation of Ta, Sb, and Nb from model solutions, which are close in composition to the reprocessed tantalite-columbites, has been suggested.