Effects of the fragmentation type on the down-stream recovery of value-added metals from e-waste and composite materials

Abstract

This study examines the effects of the fragmentation type on the down-stream recovery of value-added metals from e-waste and composite materials, in particular of printed circuit boards (PCB). It describes the effect on the Selfrag fragmentation on the PCB and the copper liberation. It also examines the effects on the metal accustomed \textit{A. ferrooxidans} and \textit{A.thiooxidans} on the copper bioleaching. The size-reduction of the PCB was performed using a hammer mill and a Selfrag, and the energy consumed was measured. The output material has had its chemical composition analysed, as well as its particle size distribution. Three leaches were performed on the output from the hammer mill, as well as six bioleaches, three using the adapted bacteria and three using the non-adapted ones. For the Selfrag output, one leaching, one bioleaching using the adapted bacteria and one bioleaching using the non-adapted ones were performed. All tests were performed at the same conditions, except the initial $Fe^{3+}$ concentration. The fragmentation type didn't influence the copper recovery, as internal layers were still unavailable. The abiotic leaches were found to be slightly more efficient, even tough uncertainties remained. The effect of the accustoming of the bacteria mix couldn't be seen.