Separation of cerium from mixed rare earth in the rare earth hydroxide concentrates by calcination and leaching using hydrochloric acid

Abstract

This study aims to determine the optimum conditions for the separation process of Ce from a mixture of rare earths in the rare earth hydroxide concentrate for variations in the concentration of hydrochloric acid, operating temperature and contact time. This experiment was carried out by calcining the rare earth hydroxide concentrate at 1000 °C for 2 hours followed by leaching in hydrochloric acid with various concentrations of 0.3, 0.6, 0.9 and 1.2 M, temperature 30, 45, 60 and 75 °C, ratio of feed to solvent (mass / volume) 1: 5 and variation of contact time 5, 10, 15 and 20 minutes. The results of REE leaching in the residues were analyzed by XRF. The optimum leaching process was achieved at a hydrochloric acid concentration of 0.9M, temperature of 75 °C, and contact time of 10 minutes with the leaching efficiency of Y, La, Ce, Pr and Nd respectively 4.078%, 79.472%, 0.049%, 49,901% and 46,844%. In this condition the separating factors Y, La, Pr and Nd with respect to Ce were 20.283, 29.69×103, 18.62 × 103 and 16.73 × 103.