Salting Out Effect of Electrolyte Solutions in The Extraction of Tantalum and Niobium Using Aqueous Biphase System

Abstract

The salting-out effect of various solutions of electrolyte in the extraction of tantalum and niobium using aqueous biphasic system (ABS) was investigated. This was achieved by leaching ball-milled Tantalite ore with mineral acids (H2SO4 and HF) in the ratio of 3:1. The leached liquor was then divided into five parts and each part mixed with ABS formed (e.g. PEG-3350/20wt/wt Na₂CO₃) for the extraction of tantalum and niobium and then with Na₂SO₄, K₂CO₃, K₂SO₄, KBr, and KI salts in turn. The amount of tantalum pent oxide extracted was determined using X-ray fluorescence method. The results show that the percentage tantalum extracted was in the range of 28.17% to 54.93% i.e. increased in the order KI< KBr < K₂CO₃< Na₂SO₄, < K₂SO₄ with 28.17%, 30.28%, 34.51%, 43.31% and 54.93% respectively; while that of niobium pent oxide increased in the order KI< KBr < K₂CO₃< Na2SO₄, < K₂SO₄ with 27.3%, 29.35%, 33.78%, 34.64% and 41.98% respectively. In conclusion electrolyte with high ionic charge and hydration radius salts-out Ta₂O₅ better in the ABS/electrolyte system than those with low values.

Keywords: Tantalum, niobium, salting-out, extraction, aqueous biphase