Electrochemical Recovery of Iron from Spent Pickle Liquor by Chloride-Based Molten Salt Electrolysis

Badalbayli, Anar; Sinclair, Nicholas; Kim, Eunjeong; Baker, Alexander A.; Akolkar, Rohan

doi:10.1149/2754-2734/ae114b

Electrochemical Recovery of Iron from Spent Pickle Liquor by Chloride-Based Molten Salt Electrolysis

Journal Article · Thu Oct 23 00:00:00 EDT 2025 · ECS Advances

DOI:https://doi.org/10.1149/2754-2734/ae114b· OSTI ID:3003812

^[1]; ^[1]; Kim, Eunjeong ^[2]; Baker, Alexander A. ^[2]; ^[1]

Case Western Reserve Univ., Cleveland, OH (United States)
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Spent pickle liquor (SPL) is a waste stream generated in the steel industry that presents both a disposal challenge and a potential resource for metal recovery. This study investigates the electrochemical extraction of high-purity iron metal from SPL using chloride-based molten salt electrolysis (CMSE). Electrochemical characterization of diluted SPL confirmed Fe²⁺ as the dominant species. Thermal dehydration of SPL under inert atmosphere yielded FeCl₂-rich solids, which were directly employed as feedstock for electrolysis in LiCl–KCl eutectic melts at 500 °C. Cyclic voltammetry of FeCl₂ in this melt revealed well-defined Fe²⁺/Fe⁰ redox behavior within the electrochemical stability window of the supporting electrolyte. High coulombic efficiency (>85%) electrodeposition was achieved demonstrating that iron metal can be produced from dehydrated SPL by CMSE. The electrodeposited iron exhibited >98 wt% purity, which was further enhanced to 99.9 wt% via arc melting. The resulting iron powder was ferromagnetic, and its size distribution was found to be suitable for powder metallurgy applications. This work demonstrates a scalable, energy-efficient pathway for valorizing SPL into high-purity iron metal, advancing circular economy strategies in the steel industry.

View Accepted Manuscript (DOE)

Research Organization:: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Organization:: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Industrial Efficiency & Decarbonization Office (IEDO)

Grant/Contract Number:: AC52-07NA27344; EE0010846

OSTI ID:: 3003812

Report Number(s):: LLNL--JRNL-2009696

Journal Information:: ECS Advances, Journal Name: ECS Advances Journal Issue: 4 Vol. 4; ISSN 2754-2734

Publisher:: IOP PublishingCopyright Statement

Country of Publication:: United States

Language:: English

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