Abstract
Precious metal (PM) retrievement from e-waste is of great significance for reducing virgin mining activity and promoting rare resource sustainability. However, current PM recycling methods rely mainly on caustic aqua regia or unstable sulfur-based ligand, which has caused severe environmental damage and process inefficiency. Here, we propose an environmentally friendly halide-regulated strategy, utilizing milder and renewable oxidant—cupric/ferric ion for facile PM dissolution. This is realized by the synergistic effect of enhanced oxidizing ability of Cu(II) and reduced oxidation potential of PM with halide addition. Electrochemical tests and leaching experiment results show that Cu(II)/Cu(I) redox potential experiences great change with bromide, increasing from 0.4 to 0.75 V. Fast corrosion feature was observed for Au in Cu(II)/Fe(III)-Br- and Pd in Cu(II)/Fe(III)-Cl-, and it can be accelerated by increasing oxidant and halide concentration. Our proposed strategy outperforms traditional methods with stable and fast dissolution, where 2.5 mol/L Br- is appropriate for Au dissolution. Moreover, selective dissolution of base metal, Pd/Ag, and Au can be achieved via ligand alteration and be further combined with electrodeposition technique for multi metal recovery and oxidant regeneration. This halide-regulated strategy can lead PM recycling from pollutive status towards environmentally friendly road.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
