NEW LEAD ANODE FOR COPPER ELECTROWINNING R. Prengaman President Timothy W. Ellis Vice President Abbas H. Mirza* Senior Process Engineer *Author Correspondent RSR Technologies, Inc. 2777 North Stemmons Fwy, Suite 1800 Dallas, TX 75207 USA Phone: (214) 242-0357 ________________________________________________________________ Keywords: Lead anodes, rolled lead calcium tin alloys, cobalt, manganese, corrosion ABSTRACT Lead calcium tin anodes have been used for copper electrowinning for many years. Prengaman (1) developed the first rolled lead calcium tin alloy anode in the early 1980’s. These anodes have remained virtually unchanged since that time. Improvement in treatment and filtration of copper electrolyte has improved anode life. The addition of about 50-200 ppm cobalt to the electrolyte has also increased the anode life. The cobalt decreases the anode potential and permits the increased evolution of oxygen which reduces anode corrosion, reduces the deleterious effects of manganese and increases anode life. However, much of the cobalt is lost in the bleed from the tankhouse. RSR Technologies has developed a new anode for copper electrowinning which contains cobalt as an alloying element in the traditional rolled lead calcium tin anode. In the copper EW cell, the anode produces lower oxygen overpotential. The cobalt in the anode is not lost into the solution, but remains on the anode surface and dopes the PbO2 corrosion product. The cobalt is continually renewed at the anode surface. The new anode should enable operators of copper EW tankhouses to eliminate or greatly reduce cobalt additions to the electrolyte. This paper will describe the new anode, discuss some field trials, and estimate cost savings due to the reduction in cobalt additions to the tankhouse electrolyte. BACKGROUND
NEW LEAD ANODE FOR COPPER ELECTROWINNING R. Prengaman President Timothy W. Ellis Vice President Abbas H. Mirza* Senior Process Engineer *Author Correspondent RSR Technologies, Inc. 2777 North Stemmons Fwy, Suite 1800 Dallas, TX 75207 USA Phone: (214) 242-0357 ________________________________________________________________ Keywords: Lead anodes, rolled lead calcium tin alloys, cobalt, manganese, corrosion ABSTRACT Lead calcium tin anodes have been used for copper electrowinning for many years. Prengaman (1) developed the first rolled lead calcium tin alloy anode in the early 1980’s. These anodes have remained virtually unchanged since that time. Improvement in treatment and filtration of copper electrolyte has improved anode life. The addition of about 50-200 ppm cobalt to the electrolyte has also increased the anode life. The cobalt decreases the anode potential and permits the increased evolution of oxygen which reduces anode corrosion, reduces the deleterious effects of manganese and increases anode life. However, much of the cobalt is lost in the bleed from the tankhouse. RSR Technologies has developed a new anode for copper electrowinning which contains cobalt as an alloying element in the traditional rolled lead calcium tin anode. In the copper EW cell, the anode produces lower oxygen overpotential. The cobalt in the anode is not lost into the solution, but remains on the anode surface and dopes the PbO2 corrosion product. The cobalt is continually renewed at the anode surface. The new anode should enable operators of copper EW tankhouses to eliminate or greatly reduce cobalt additions to the electrolyte. This paper will describe the new anode, discuss some field trials, and estimate cost savings due to the reduction in cobalt additions to the tankhouse electrolyte. BACKGROUND
New%20Lead%20Anode%20for%20Copper%20Electrowinning.docx