Chemical and Microbial Leaching of Valuable Metals from PCBs and Tantalum Capacitors of Spent Mobile Phones

Asma Sikander, Steven Kelly, Kerstin Kuchta, Anika Sievers, Thomas Willner and Andrew S. Hursthouse ()
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Asma Sikander: Department of Process Engineering, Hamburg University of Applied Sciences, Ulmenliet 20, 21033 Hamburg, Germany
Steven Kelly: School of Health Life Sciences, University of the West of Scotland, Scotland G72 0LH, UK
Kerstin Kuchta: Institute for Environmental Engineering and Energy Economics, TUHH—Hamburg University of Technology, 21079 Hamburg, Germany
Anika Sievers: Department of Process Engineering, Hamburg University of Applied Sciences, Ulmenliet 20, 21033 Hamburg, Germany
Thomas Willner: Department of Process Engineering, Hamburg University of Applied Sciences, Ulmenliet 20, 21033 Hamburg, Germany
Andrew S. Hursthouse: School of Computing, Engineering & Physical Sciences, University of the West of the Scotland, Scotland PA1 2BE, UK

IJERPH, 2022, vol. 19, issue 16, 1-17

Abstract: We compared chemical and microbial leaching for multi-metal extraction from printed circuit boards (PCBs) and tantalum capacitor scrap. A mixed consortium of acidophiles and heterotrophic fungal strains were used in the experiments and compared to chemical leaching using specific acids (sulfuric, citric and oxalic acids). Under optimum conditions, 100% extraction efficiency of Cu, and nearly 85% of Zn, Fe, Al and Ni were achieved from PCB and tantalum capacitor scrap samples using sulfuric acid. The mixed consortium of acidophiles successfully mobilized, Ni and Cu (99% and 96%, respectively) while Fe, Zn, Al and Mn reached an extraction yield of 89, 77, 70 and 43%, respectively, from the PCB samples. For the tantalum capacitor samples, acidophiles mobilized 92% Cu, 88% Ni, 78% Fe, 77% Al, 70% Zn and 57% Mn. Metal mobilization from PCBs and tantalum capacitor scrap by A. niger filtrate showed efficient solubilization of Cu, Fe, Al, Mn, Ni, Pb and Zn at an efficiency of 52, 29, 75, 5, 61, 21 and 35% from PCB samples and 61, 25, 69, 23, 68, 15 and 45% from tantalum capacitor samples, respectively. Microbial leaching proved viable as a method to extract base metals but was less specific for tantalum and precious metals in electronic waste. The implications of these results for further processing of waste electronic and electrical equipment (WEEE) are considered in potential hybrid treatment strategies.

Keywords: bioleaching; tantalum; WEEE; acidophiles; waste management; green technology (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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