An investigation of copper and selenium recovery from copper anode slimes

• An alternative method to recover copper and selenium from anode slime was designed.
• The critical process parameters were investigated and optimized.
• 2 L/min flow rate of oxygen was enough to achieve the maximum dissolution rates.
• The maximum recovery of copper and selenium was found as 94% and 86%, respectively.
• The dissolution kinetic of selenium was examined according to Shrinking-core model.

In this study, an alternative method was investigated for the recovery of copper and selenium from copper anode slimes, supplied from Sarkuysan Co. in Turkey. The proposed process was composed of two hydrometallurgical steps; decopperization in H2SO4 medium and dissolution of selenium into NaOH solution. The effects of oxygen flow rate and solution temperature on the decopperization of anode slimes were examined in H2SO4 medium and copper recovery was achieved with an efficiency of 94%. The X-ray diffraction (XRD) analysis revealed Cu2Se as a remaining phase of copper in anode slimes after the decopperization process. Following the decopperization stage, anode slimes were treated with NaOH solution in order to dissolve selenium. The influences of NaOH concentration, temperature and various types of oxidants on selenium dissolution were inspected. The uniqueness of this technique is that it provides to have an efficiency of selenium recovery as high as 86.8% in an alkaline solution (4 M NaOH) under atmospheric conditions without requiring an autoclave.