Effect of electrode pulsation on the rate of simultaneous electrochemical recovery of copper and regeneration of ferric salts from dilute solutions

Abstract

The effect of vertical plate electrode pulsation on the rate of cathodic copper deposition and anodic oxidation of ferrous sulphate was studied in a divided cell. Electrode oscillation was found to enhance the rate of diffusion controlled copper deposition and ferrous sulphate anodic oxidation by a factor ranging from 1.9 to 7.8 compared to the natural convection value depending on the vibration velocity. Electrode pulsation was found to increase the current efficiency of copper deposition from 52% to 98%, while the current efficiency of anodic oxidation of FeSO 4 increased from 35% to 92% depending on the vibration velocity. Also, electrode vibration was found to decrease electrical energy consumption of copper deposition from 4 to 1.56 kWh/kg; for anodic oxidation of FeSO 4 electrode vibration reduces energy consumption from 3.35 to 1.25 kWh/kg depending on vibration velocity. The importance of the present results for treating dilute solutions containing copper and ferrous ions such as printed circuit etching solution, pickling waste solutions, chemical machining waste solution, mine drainage water, leaching liquor obtained by leaching low grade copper sulphide ore by ferric salts was highlighted. The present technique has the advantage of recovering a precious metal and recycling a valuable chemical in one step, this satisfies the policy of zero discharge industry.