Reclamation of Precious Metals from Small Electronic Components of Computer Hard Disks

Present research work focuses on the recovery of precious metals (Ag, Au, Pd, and Pt) from the leach liquor of small populated chips present in the hard disk of computers. Initially, the hard disks were dismantled to separate the printed circuit boards (PCBs) followed by its depopulation to liberate the mounted small electronic components. The liberated black chips were pulverized to ~100 mesh and chemically analysed. The powdered black chips containing ~0.6% Ag, ~0.3% Au, ~0.01% Pd, ~0.0003% Pt, and 20% Cu on mass basis were first leached in nitrate medium for maximum dissolution of non-ferrous metals along with Ag leaving Au, Pd, and Pt in the residue. About 99.99% of precious metals were leached out from the residue using suitable lixiviant. The obtained leach liquor was purified using advanced separation techniques (solvent extraction/ ion-exchange/ precipitation) from which marketable products (metals/ salts) could be produced.