Recovery of platinum, tin and indium from spent catalysts in chloride medium using strong basic anion exchange resins.

This work describes a route for platinum recovery from spent commercial Pt and PtSnIn/Al(2)O(3) catalysts using strong basic mesoporous and macroporous anion exchange resins (Cl(-) form). The catalysts were leached with aqua regia (75 °C, 20-25 min). Platinum adsorption was influenced by the presence of other metals which form chlorocomplexes (tin, indium) and also base metals (aluminum). However, it was possible to overcome this fact by a sequential desorption procedure. Aluminum was selectively removed from the resins by elution with 3 mol L(-1) HCl. Platinum was desorbed passing 1 mol L(-1) Na(2)S(2)O(3) (pH 9). Tin was removed by elution with 0.1 mol L(-1) ascorbic acid. Indium was removed using 0.1 mol L(-1) EDTA as eluent. Desorption efficiency exceeded 99% for all metals. Metals were recovered in high yields (>98 wt%).