Recycling of metallic values from discarded tantalum capacitors

Abstract

The generation of electronic waste generation has led to significant attention towards metal recovery from urban sources. Due to scarcity, finite resources, and geopolitical constraints, tantalum recycling from capacitors is essential. In this study, sequential separation involving the removal of tightly bound epoxy resin and metallic impurities is carried out. Pyrolysis as a pre-treatment and its response on phase transformation, resin decomposition and metal enrichment are investigated. Pyrolysis effectively liberates the tantalum-rich sintered core from outer resin which is followed by mild organic acid leaching. The manganese impurity was removed from the core to obtain Ta recovery of ∼94.8% with ∼96% purity in the leach residue. The separated resin component was subjected to conventional sink-float separation for the recovery of metallic values (silver, tantalum). It is found that 100 g (666 units) of Ta capacitors can yield 34 g of Ta, equivalent to 0.28 tons of primary ore.