Bio-Assisted Leaching of Non-Ferrous Metals from Waste Printed Circuit Boards—Importance of Process Parameters

The effect of varying process parameters during bio-catalyzed leaching metals from end-of-life printed circuit boards (PCBs) was investigated. Fragmented PCBs (under 2 mm) were subjected to an indirect bioleaching in a stirred tank reactor while pulp density, pH and initial ferric iron content varied. An oxidizing Acidithiobacillus ferrooxidans 61 microbial strain used generate the lixiviant through Fe(II) Fe(III). Chemically generated Fe(III) tested as under same conditions biological one for comparative purposes. Cell enumeration microscopic observations input leached conducted parallel shed light on observed phenomena. degree bringing solution found depend mainly concentration pH. For entire duration being always kept 24 h, substantial portion Cu (~87%) extracted respectively at 1% density (PD), 15.5 g/L Fe3+ 1. Zn Ni, nearly 100% recovery 5% PD, 18 1.1. achieved results offer possibilities further studies higher ultimately render approach enabling economical environmentally friendly technology urban mining non-ferrous metals.