Comparison of copper sludge ferritization by hydrometallurgical and pyrometallurgical process

In this study, hydrometallurgical and pyrometallurgical processes for the transformation from actual copper sludge into Copper ferrite (CuFe2O4) were investigated. Base on the results of XRD (X-ray diffraction), Ms (Saturation Magnetization) and TCLP (Toxicity Characteristic Leaching Process), the copper ferrite product was formed with ferromagnetic properties. As F6/M molar ratio was increased, both the crystalline phase and Ms of Cu-ferrites was increased. Even through the TCLP of ferrite was apparently decreased by hydrometallurgical process, but still above the regulation limit (15 mg/L). On the contrary, base on the results of XRD and Ms, it was revealed that the Cu-ferrite product with ferromagnetic properties was formed by pyrometallurgical process. As Fe/M molar ratio was increased, both the crystalline phase and Ms of Cu-ferrites was decreased due to the excess Fe,03 addition. It was evident that TCLP of Cu-ferrite product was below the regulation limit (15 mg/L) when Fe/M > 3.5 after 15hr isothermal time at 800 degrees C. Consequently, pyrometallurgical process was more effective in copper sludge stabilization than hydrometallurgical process.