Improving current efficiency
We produce Zinc through electrowinning at a power consumption of 3300 kwh/Tonne of cathode. The cellhouse power is maintained at 13 KA during the stripping of cathodes (manual-once in 24 hrs) and 15 KAmps afterwards. The cell feed zinc is 60 gms/ltr and acidity of the spent electrolyte is 170 gms/ltr. The average cell temps are around 42 to 43 °C. The current density is at 440 KAmps/hr on avg. How can the current efficiency be improved to 90% and above? What is the relation between current efficiency, current density, cell temperatures and power consumption?G Balaji
There are many factors which affect the efficiency of the system like mass transfer, Electrode over potential, interelectrode gap, cell design, type of cell etc. It depends on how efficiently you stop the other reactions and enhance the preferred reaction, a very good cell design is important to get a good efficiency. Feed concentration do play a part but more to do with the Electrochemical cell design. You can refer some books or there are some people who can do it for you. Refer to Central Electro Chemical Research Institute at Karaikudi in Tamilnadu they do have lot of expertise on Electrowinning of Zinc.
Dear Mr. Balaji,
After going through your problem I found that with the information you have given it is difficult to tell you the actual problem where you loose energy rather than converting the same for zinc deposition. If possible you can visit our institute "Regional Research Laboratory (CSIR), Bhubaneswar where we work on electrowinning of non-ferrous metals like copper, nickel, Cobalt and zinc". I hope we can help you to sort out your problem.
Dr. B.C. Tripathy
Hydro & Electrometallurgy Department,
Regional Research Laboratory
- Bhubaneswar, Orissa, India