Elsevier

Minerals Engineering

Volume 173, 1 November 2021, 107189
Minerals Engineering

Handling trace elements in WEEE recycling through copper smelting-an experimental and thermodynamic study

https://doi.org/10.1016/j.mineng.2021.107189Get rights and content
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Highlights

  • Experimental study on recycling WEEE through copper smelting.

  • Ag can be effectively recovered into copper alloy at all conditions.

  • Co and Ni favored the solid phases compared to their dissolution in slags.

  • Ni and Sn were concentrated in copper alloy at lower PO2 but in slag at higher PO2.

  • Higher temperatures and lower PO2 favor the deportment of trace elements into the copper alloy.

Abstract

Recycling of waste electrical and electronic equipment (WEEE) is attracting increasing attention, due to the presence of valuable metals and the risk of environmental emissions associated with WEEE disposal. In this study, the distributions of trace elements (Ag, Ni, Co, and Sn) between copper alloy and magnetite/wüstite-saturated iron silicate slags were investigated at 1200–1300 °C and PO2 of 10-10-10-6.5 atm, simulating the conditions of WEEE reprocessing through secondary copper smelting and converting. The high-temperature isothermal equilibration experiments were conducted in synthesized magnetite/wüstite crucibles under controlled CO-CO2 atmospheres followed by quenching in an ice-water mixture. The phase compositions and concentrations of the trace elements in copper alloy, magnetite/wüstite, and slag were determined by Electron Probe X-ray Microanalysis and Laser Ablation-High-Resolution Inductively Coupled Plasma-Mass Spectrometry. The distribution coefficients of all investigated trace elements between copper alloy and slag increased with decreasing oxygen partial pressure and increasing temperature. Ag distributed strongly into the copper alloy at all conditions, whereas Co mainly deported into the slag phase. Ni and Sn were concentrated in the alloy at lower PO2 and in the slag at higher PO2. Varying concentrations of Ni, Co, and Sn were also dissolved into the solid magnetite/wüstite phase.

Keywords

Trace elements
WEEE
Circular economy
Resource efficiency
Copper smelting

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