Chloride-assisted electrochemical conversion of Fe-Cr-Ni alloy scrap into oxide powders for enhanced acid leaching
Year: 2026
Type: article
Abstract: This study investigates a chloride-assisted electrochemical conversion process for transforming compact, passivated Fe-Cr-Ni alloy scrap into recoverable oxide powders with enhanced acid leachability. The scrap contained 69.94 wt% Fe, 17.16 wt% Cr, and 6.90 wt% Ni. Electrochemical analyses showed that hydroxide electrolytes promoted the formation of compact oxide/hydroxide passive films, whereas chloride electrolytes induced passive film destabilization and sustained anodic dissolution. In KCl electrolyte, anodically released metal species subsequently precipitated and were recovered as oxide powders containing Fe 2 O 3 , Cr 2 O 3 , and NiO. Increasing the KCl concentration from 1 to 4 mol/L increased ionic conductivity and lowered the anode potential required to maintain the imposed current density. Among the examined conditions, 4 mol/L KCl provided the lowest and most stable anode-potential response while maintaining a powder yield comparable to those obtained at 2–3 mol/L. The electrochemically formed oxide powders exhibited an average particle size of 144.2 nm at 4 mol/L KCl. Under identical leaching conditions of 4 mol/L H 2 SO 4 at 50 °C for 30 min, dissolution efficiencies increased from 10.46%, 8.13%, and 9.23% for Fe, Cr, and Ni in untreated bulk scrap to 93.47%, 92.41%, and 96.64%, respectively, for the electrochemically formed oxide powders. This comparison indicates that the improved leaching response resulted from coupled electrochemical phase conversion and powder formation, rather than from an isolated particle-size reduction effect. These results demonstrate that chloride-assisted electrochemical conversion serves as an upstream activation step for downstream hydrometallurgical processing of passivated Fe-Cr-Ni alloy scrap.
Source: Electrochemistry Communications
Institutions: Korea University, Korea Institute of Industrial Technology
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,630
OpenAlex ID: W7223241733