EXTRACTION CHARACTERISTICS OF NIOBIUM(V) AND TANTALUM(V) ON TRIOCTYLMETHYL AMMONIUM CHLORIDE-IMPREGNATED POLYURETHANE FOAM

A reagent-impregnated polymer material has been prepared with trioctyl methyl ammonium chloride (TOMAC) and polyurethane foam as a new type o f extractant for niobium and tantalum. Niobium(V) and tantalum(V) can be easily concentrated from their hydrofluoric acid solutions with TOM AC-impregnated polyurethane foam. The log D value for tantalum(V) is m ore than 4 in the HF concentration range from 0.5 to 2 mol . L(-1). Th e recovery of tantalum(V) from hydrofluoric acid solutions containing a large amount of niobium(V) has been successfully carried out by a ba tch technique. Extraction characteristics of the present system are si milar to solvent extraction rather than to conventional anion-exchange rs with respect to the dependence of the value of log D on hydrofluori c acid concentration.