Electrolytic refinement of silver-enriched copper anodes for producing high-purity cathode copper utilizing ionic liquid additives

In the process of fabricating high-purity copper, the high silver (Ag) content in copper plates poses a significant impurity issue, adversely affecting the quality and appearance of cathode copper, such as purity and surface finish. Moreover, it diminishes the electrolytic efficiency during production and escalates costs. This study successfully reduced the silver content in cathode copper from 7 g/t to 4.5 g/t by employing 1-aminopropyl-3-methylimidazolium chloride ([C 3 NH 2 CIm][Cl]) as an single yet multifunctional additive to regulate the copper electrolytic refining process, thereby enhancing the purity of the cathode copper. The cathode copper products and anode slime prepared were characterized and analyzed using techniques such as SEM, XRD, and XPS. The findings indicated that [C 3 NH 2 CIm][Cl] exerts a flocculation effect on anode slime during electrolysis, mitigating the adhesion and inclusion of suspended anode slime in cathode copper. Furthermore, the silver decreasing efficacy of [C 3 NH 2 CIm][Cl] in the copper electrolytic refining process was investigated through electrochemical characterization. It was observed that [C 3 NH 2 CIm][Cl] can react with Ag + to form precipitates, thereby reducing the concentration of Ag + in the solution. Additionally, [C 3 NH 2 CIm][Cl] can complex with Ag + , elevating the electrode potential of Ag + during the electrolytic refining process, making it less likely for Ag + to be reduced at the cathode under comparable conditions. This research provides an effective additive strategy for improving the purity and production efficiency of copper.