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

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-11-01
Major/Subject
Mcode
Degree programme
Language
en
Pages
14
Series
Minerals Engineering, Volume 173
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.
Description
Funding Information: This study received financial support from Aalto University, School of Chemical Engineering and Business Finland funded SYMMET program (grant number 3891/31/2018). The utilization of the Academy of Finland’s RawMatTERS Finland Infrastructure (RAMI) based at Aalto University, GTK in Espoo, and VTT in Espoo is appreciated. Min Chen is grateful for the China Scholarship Council (grant number 201806370217) for a doctoral project grant. Funding Information: This study received financial support from Aalto University, School of Chemical Engineering and Business Finland funded SYMMET program (grant number 3891/31/2018). The utilization of the Academy of Finland's RawMatTERS Finland Infrastructure (RAMI) based at Aalto University, GTK in Espoo, and VTT in Espoo is appreciated. Min Chen is grateful for the China Scholarship Council (grant number 201806370217) for a doctoral project grant. Publisher Copyright: © 2021 The Authors
Keywords
Circular economy, Copper smelting, Resource efficiency, Trace elements, WEEE
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Citation
Chen , M , Avarmaa , K , Taskinen , P , Klemettinen , L , Michallik , R , O'Brien , H & Jokilaakso , A 2021 , ' Handling trace elements in WEEE recycling through copper smelting-an experimental and thermodynamic study ' , Minerals Engineering , vol. 173 , 107189 . https://doi.org/10.1016/j.mineng.2021.107189