Electrochemical performance and behavior of nickel pig Iron anodic electrolysis for enhanced sulfuric acid leaching

This study presents an innovative electrochemical method for producing ultra-fine Nickel Pig Iron (NPI) powders through anodically induced overpotential electrolysis, achieving a significantly high surface area and exceptional sulfuric acid leaching efficiency. Nickel, a critical material for energy applications, faces increasing supply constraints, leading to greater reliance on intermediates like nickel sulfate. Conventional high-pressure acid leaching (HPAL) processes, while effective, suffer from high operational costs and excessive acid waste generation. To address these challenges, this study employs anodic oxidation of NPI under high-voltage conditions (≥10 V), facilitating particle refinement and enhanced electrochemical reactivity. Electrochemical characterizations, including cyclic voltammetry, chronoamperometry, and Pourbaix diagram analysis, confirm the formation of oxidized Ni-rich phases at optimal voltage ranges with peak current exceeding 10 A. The resulting fine NPI powders exhibit a leaching efficiency surpassing 95 % in 2 mol/L sulfuric acid at ambient temperature and pressure, demonstrating their potential as a cost-effective alternative to HPAL. Further post-process evaluations reveal critical electrolysis parameters influencing oxidation behavior and leaching performance, providing key insights for optimizing nickel extraction via anodic electrolysis. • To leach and refine nickel alloys and ores, the High-Pressure Acid Leach process is essential. • Conducted an anodic oxidation process for leaching at ambient temperature and pressure. • Study of the behavior of fine powder formation through various electrochemical analyses. • The NPI particles generated in the electrolysis process achieved 95 % leaching success.