LAUSR

Abstract Separation and recovery of platinum group metals (PGM) from dilute solutions have been examined using precipitation, ion exchange, and solvent extraction. Flotation separation of palladium (Pd) was investigated in the current study. Experimental results showed that Cl- forms complexes with Pd2+ ion and rendered Pd more soluble. Changes of speciation and solubility of Pd affected flotation separation significantly. Separation efficiency of Pd at pH 2.0 increased from 4.9% to 79.4% as Cl- concentration increased from 1.4 × 10-3 to 0.1 M when using cetyltrimethylammonium bromide (CTAB) as the collector. Different collectors showed various removal efficiencies, and CTAB and 1-hexadecyltrimethylammonium chloride (HDTAC) resulted in effective separation of Pd among four cationic collectors used. Effects of collector dose on Pd removal efficiency were discussed as well. The electrostatic interaction between cationic collector and anionic Pd-Cl species (PdCl3- and/or PdCl42-) was the main mechanism for Pd flotation separation. It was demonstrated that flotation separation of Pd could be an effective technology for dilute systems.