Simultaneous sorption recovery of platinum and rhodium from sulfate-chloride solutions

The present work is devoted to simultaneous ion exchange recovery of platinum(II, IV) and rhodium(III) from sulfate-chloride solutions, freshly prepared and stored over 3 months, on commercial macroporous anion exchangers with different chemical structures. The sorption was carried out from solutions with 2.0; 0.1 and 0.01 mol/L HCl and H2SO4. The initial concentrations of platinum and rhodium in contacting solutions were 0.05-5.0 mmol/L. Sorption and kinetic properties of selected anion exchangers were investigated and the basic parameters of ion exchange capacity, recovery, distribution coefficients, separation factors, process rate, diffusion coefficients and half-exchange times were calculated. It was shown that the anion exchangers possess high sorption ability towards platinum and rhodium during their recovery from freshly prepared and stored sulfate-chloride solutions. The optimal molar ratio of hydrochloric and sulfuric acids was determined as 1:1. It was shown that freshly prepared sulfate-chloride systems have the same efficiency during simultaneous Pt/Rh recovery as chloride solutions. In case of stored systems, the sulfate-chloride solutions compare favorably with chloride ones. (C) 2012 Elsevier B.V. All rights reserved.