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

Highlights: → Platinum, tin and indium recoveries from spent reforming catalysts. → Adsorption of metal chlorocomplexes on strongly basic anion-exchange resins. → Sequential desorption via elution with reducing (Pt, Sn) or complexing (In) agents. → The elements were recovered in very high yields. → The anion-exchange resins can be reused. - Abstract: This work describes a route for platinum recovery from spent commercial Pt and PtSnIn/Al2O3 catalysts using strong basic mesoporous and macroporous anion exchange resins (Cl- form). The catalysts were leached with aqua regia (75 oC, 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 Na2S2O3 (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%).