CopperCopper anode slimesCopper anode slimes from electrolytic refining contain a significant amount of copper (>60%) along with precious and other base metals. DecopperizationDecopperization, the selective dissolution of Cu while retaining valuable metals, is a critical pretreatment step. This study investigates leachingLeaching of anode slimes using sulfuric acid in the presence and absence of hydrogen peroxideHydrogen peroxide. Different leaching parameters such as temperature, pulp density, leaching time, pH, and oxidant (hydrogen peroxide) addition were investigated. The results showed that the addition of hydrogen peroxide significantly increases leach efficiency of copper. However, the reactions are more favorable at lower (60 °C) than at higher (90 °C) temperature. Mass balances indicated that 90% of copperCopper reported to the solution (10% remained in residue), whereas only 20% of arsenic dissolved during leaching. Kinetic analysis using shrinking-core model equation (1 – (1–X)(1/3) = k_r·t and 1 – 2/3X – (1–X)(2/3) = k_d·t) yielded R2 ≈ 0.96 for surface-reaction control and R2 ≈ 0.99 for diffusion control, indicating a diffusion-controlled process. These results confirm that optimized hot oxidative leachingLeaching effectively removes copper, thus achieving decopperizationDecopperization.