Recycling of Discarded Tantalum Capacitors for Metal Recovery

The massive generation of electronic waste presents an opportunity for resource recycling. Discarded tantalum capacitors contain 30-35 wt.% tantalum, which is tightly encapsulated in an epoxy housing. Tantalum recycling is necessary due to scarcity, finite resources, and geopolitical constraints. Pyrolysis effectively degrades the epoxy resin and liberates the tantalum-rich sintered core from the outer resin. The manganese (MnO2) was removed from the core using mild acid leaching to concentrate tantalum in the leach residue. Pyrolysis temperature (550-700 degrees C) influences the transformation of MnO2 to lower oxides, thereby affecting its dissolution. The decomposed epoxy housing consists mainly of silica and silver, which is subjected to density separation. The metallic enrichment in the underflow fraction is limited due to finer silver particles. Nearly, 100 g capacitors can yield 34 g of Ta, equivalent to 0.28 tons of primary ore.