Q: I use a conventional electrowinning circuit to recover copper from my pickling solution. What are the benefits of using the EMEW® technology?
A: In order for the pickling process to be efficient, copper concentration needs to be kept low (and acid high). In conventional electrowinning this is difficult to efficiently achieve below 20 grams per liter (20,000 ppm). Using EMEW® electrowinning, copper concentration can easily be controlled below 3 grams per liter, thus maximizing the efficiency of the pickling bath.

Conventional electrowinning uses lead anodes which anodically dissolve and can contaminate the bath and the copper product. EMEW® electrowinning uses DSA anodes which do not dissolve.

Q: We use a copper sulphate production facility to process the spent pickling solution, what would be the drivers in replacing this process with EMEW® electrowinning?
A: Production of copper sulphate has a proportionally high operational cost. Based on recent analysis, the replacement of such a plant with an EMEW® electrowinning facility would provide a payback of between 18 and 36 months.

This is primarily achieved through the drastic reduction in the use of acid, and the higher value obtained from 99.99% copper cathode.

Q: What are the typical current efficiencies that can be achieved using the EMEW® technology?
A: 92% to 95% is common for acid pickling solutions.

Q: What purity of copper cathode will the EMEW® technology produce?
A: >99.99% is common for acid pickling solutions.

Q: What happens to the acid when the copper is electrowon from the solution?
A: It is returned to the pickling bath and reused.

Q: Electrowinning produces acid mist. What requirements will there be for providing a safe working environment?
A: During conventional electrowinning of copper, oxygen bubbles are produced at the anodes. When these bubbles reach the surface they burst, liberating an aerosol of sulfuric acid called acid mist, which can affect the health of operators, the environment and plant infrastructure, The EMEW® technology captures ALL gases that can be generated and makes them available for collection and safe disposal or reuse. This feature of EMEW provides significant improvements to the working environment. There is no requirement for surfactants, surface foam or vented tankhouse hoods.

Q: To what level can the EMEW® cell recover metals?
A: Again this does depend somewhat on the solution chemistry and the target metals. However in the case of copper the EMEW® cell has achieved a discharge level of 0.1 ppm.

Q: Does the EMEW® cell have any moving or rotating parts?
A: No, the pump is the only moving part of the plant.

Q: What is the flow rate through each cell?
A: Approximately 6000 liters per hour in the plating cell and 2000 liters per hour in the powder cell.

Q: At what weight will the cathode require harvesting?
A: Approximately 25 kg.

Q. How long does it take to harvest a single cell/cathode?
A. About 2 to 3 minutes for plating cells.

Q. What is the anode made of?
A. For low pH solutions the anode (DSA®) is made from a titanium tube that is coated with iridium oxide. For high pH solutions the anode is typically constructed of stainless steel.

Q. What is the life of the anode?
A. Electrometals use the world leading Dimensionally Stable Anode (DSA®) from the De Nora Group. In most cases the anode life is 4 to 6 years, at which point the anode may require recoating.

Q. How much cathode area is there in a commercial EMEW® plant?
A. Depending on the application this can vary from only a few square centimeters to over 1000 M².

Q. Are there any commercial EMEW systems installed?
A. Yes, we have commercial facilities in Asia, Africa, North America, South America and Europe.

Q. Is electrowinning a new process?
A. No, electrowinning has been a commercial process for almost 100 years.

Q. How uniform in thickness is the copper cathode?
A. Very uniform as the current distribution is very even.

Q. How does the copper cathode quality differ to that of conventional EW?
A. It will be higher purity as the EMEW® process is less prone to contaminants.