Characterization of extracting Cu from the circuit plank sludge with sulfuric acid

Extracting Cu from the circuit plank sludge with sulfuric acid was carried out. The effects of reaction time, liquid-to-solid ratio and the volume of sulfuric acid on the extraction rate were investigated. The experimental results show that, the circuit plank sludge has a high concentration of Cu, which is 80.7mg/g wet sludge. In leaching process, the Cu extraction rate rises at first and then declines with the increase of solid-liquid rate, and the extraction rate can reach to 98.6% when the solid — liquid rate is 5. The extraction rate increases with the increase of reaction time, and it can reach to 98.4% when the reaction time is 20min. The volume of sulfuric acid has a significant impact on the extraction rate. The extraction rate of Cu rises obviously with the increase of the volume of sulfuric acid, with nearly completely leaching when the volume of sulfuric acid is 4ml for 5.0g wet sludge. In leaching process, Fe and Zn in the circuit plank sludge can also be leached, but their maximum extraction rate are low, with values of 61.22% and 24.43% of Fe and Zn, respectively. It can be concluded with low concentrations of Fe and Zn in circuit plank sludge that recovery of Cu from leaching liquid will be favorable under proper conditions.