Combination of mineral processing and leaching steps to produce a Pd-concentrate from spent electronic components

In a context of depletion of resources and tensions on supplies, it is now becoming necessary to develop recycling methods for end-of-life wastes that may contain high metal contents. With this objective, the CAREME project aims to produce new Pd and Au catalysts from electronic waste via short routes without intermediate production of pure metals. In this project, the first step consists in the production of a Pd concentrate from electronic waste in order to increase Pd content together with the removal of less valuable fractions. The waste targeted was spent integrated circuits (IC) and particularly Plastic Leaded Chip Carrier (PLCC). After characterizing the waste, this article presents different stages of mineral processing (grinding, sieving and gravimetric separation) in order to produce a Pd pre-concentrate. Afterwards, a leaching step of the pre-concentrate using Fe(III) in acidic medium (H₂SO₄) was performed to reduce the base metal content. The Pd content was increased by 23.4 between the initial waste and the final concentrate (Pd content of 4 890 mg.kg^-1) while the base metal content (Al, Co, Cu, Fe, Mn, Ni, Pb and Zn) was reduced to 6.55 wt%. From this data, a theoretical flowsheet was established. Pd content, enrichment ratio and recovery yield were estimated.