Solvent extraction of niobium, tantalum and titanium with trialkylbenzylammoniumchloride from tartaric acid solutions

Extraction of niobium, tantalum, and titanium from tartaric acid solutions with trialkylbenzeneammonium chloride (TABAC) in toluene has been studied. The aim of investigation is extraction separation of niobium and tantalum from titanium which interferes with photometric determination of these elements. As alkyl radicals, TABAC contains hydrocarbon chains consisting of 16-18 carbon atoms. When concentration of an extracting agent changes from 0.01 to 0.4 M, the distribution coefficients of metals increase, reaching maxima at TABAC concentration equal to 0.2 M. The distribution coefficients of niobium and tantalum rise with concentration of tartaric acid. The most complete extraction of niobium and tantalum into an organic phase is observed at concentration of tartaric acid 0.4-0.8 M(pH 1.5-1.3). The Me:TABAC ratio in the compound being extracted equal to 1:1 has been determined (conventional extraction constants for niobium, tantalum, and titanium are 6.6.104, 2.2.104, and 5.8.102, respectively). The effect of different organic solvents on extraction of the above metals in the form of compounds with TABAC from tartaric acid solutions has been studied. The most effective solvents turn to be those with a low value of dielectric constant: carbon tetrachloride, benzene, toluene