Removal and recovery of titanium (IV) from leach liquor of high-sulfur bauxite using calcium alginate microspheres impregnated with di-(2-ethylhexyl) phosphoric acid

Abstract

Abstract In the leaching solution of high-sulfur bauxite roasted by sulfuric acid, a high concentration of aluminum presented along with titanium and iron. The present work was to remove Ti(IV) from the leach liquor by calcium alginate microsphere sorbent material (CA-P204) based on natural alginate impregnated with di-(2-ethylhexyl) phosphoric acid (D2EHPA) to purify leaching solution. Cation exchange and chelation make major contributions to the adsorption mechanism according to Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis. The results showed that Ti(IV) was successfully removed by the CA-P204 adsorbent from the Ti(IV)−Al(III)−Fe(III) ternary system with a dynamic column experiment. The removal rate of titanium was nearly 95% under optimal conditions and the maximum adsorption capacity was 66.79 mg/g at pH 1.0. Reusability of CA-P204 was evaluated over three consecutive adsorption/desorption cycles. The adsorption process was simple, low-cost, and had no waste discharge, suggesting that the CA-P204 was promising, efficient, and economical for removing Ti(IV) from high-sulfur bauxite leaching solution.