Gallium and Indium Selective Sulfidation and Vapor Phase Transport from e-Waste Feedstocks
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11837_2025_Article_7623.pdf
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6.75 MB
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33c2469c44493618b8f56a4055320691
Author(s)
Benderly-Kremen, Ethan
Daehn, Katrin
Allanore, Antoine
Date Issued
August 25, 2025
Journal
JOM
Publisher
Springer US
Citation
Benderly-Kremen, E., Daehn, K. & Allanore, A. Gallium and Indium Selective Sulfidation and Vapor Phase Transport from e-Waste Feedstocks. JOM 77, 7415–7434 (2025).
Version
Final published version
Abstract
Gallium (Ga) and indium (In) share similarities in their chemical behavior, their dilute presence in waste electronics (e-waste), and recycling rates close to 0% from such streams. Designing processes to extract gallium from LED chips and indium from LCD screens simultaneously reveals the potential and necessary distinctions for a flexible process based on elemental sulfur reactivity, which can be applied to both feedstocks. Whereas Ga- and In-compounds found in e-waste (gallium nitride, GaN; indium tin oxide, ‘ITO’) are recalcitrant to dissolution in aqueous feedstocks, the reaction with sulfur gas to form volatile sulfides may support their selective extraction from prepared e-waste. Process conditions for selective sulfidation are herein informed from thermodynamics and demonstrated experimentally. Vapor phase transport of the volatile sulfides is a powerful means to collect and enrich gallium and indium. Practical implementation likely calls for physical separation approaches to disassemble e-waste, remove excess material (epoxy, glass, metallic leads, and housing) from LED chips, and expose the ITO layer within LCD screens.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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Creative Commons Attribution
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DOI of Published Version
https://doi.org/10.1007/s11837-025-07623-5
