Solvometallurgical leaching for selective extraction of platinum-group elements from end-of-life autocatalysts, electronic waste and tailings

Different lixiviants based on organic solvents will be developed with the aim to selectively dissolve PGMs (Pt, Pd or Rh) from end-of-life autocatalysts, electronic waste and tailings. . A first class of lixiviants consists of CuCl2 or FeCl3 dissolved in DMSO, DMF or acetonitrile, and where Cu(II) and Fe(III) acts as oxidizing agents. In contrast to in aqueous solutions, these metal ions are strong oxidants in organic solvents because copper(I) and iron(II) are the stable species in these solvents. A second class of lixiviants are bromine or iodine dissolved in organic solvents (methanol, DMF, DMSO), with or without addition of bromide or iodide salts. A third class of lixiviants are triiodide or tribromide salts of quaternary ammonium salts, used in pure liquid form or dissolved in organic solvents. Different process parameters are investigated (type of lixiviant, temperature, solid-to-liquid ratio, ...) in order to find the conditions for selective dissolution of palladium, platinum or rhodium. The leachates are further purified by non-aqueous solvent extraction or by non-aqueous ion exchange. Non-aqueous ion exchange is carried out by cation or anion exchange resins, or chelating resins, swollen in organic solvents.