emew Electrowinning

Conventional electrowinning involves placing an anode and cathode into a bath of slowly circulating or stagnant electrolyte. The metal ions eventually make their way to the cathode via diffusion to be plated. With emew electrowinning, the electrolyte is circulated rapidly past the anode and cathode at a very high flow rate, significantly enhancing mass transfer and allowing for improvements in efficiency and recovery.

“Novel electrochemical cell designs are emerging as alternative process units for various applications in industry. Most of the advances in electrochemical cell design are in the field of improving mass transfer. Improved mass transfer allows increased specific production capacity, reduced footprint, increased selectivity, and plating from lower concentrations. One of the designs gaining acceptance in industry is the annular/tubular/cylindrical electrochemical cell. It is concluded that swirl flow significantly improves mass transfer over axial flow in annular electrochemical cells due to the slower formation of the diffusion layer.”

Source: Mass Transfer in Annular Cylindrical Electrochemical Cells, Etienne Roux

emew electrowinning
conventional electrowinning vs emew electrowinning

emewPlate

The emewPlate cell is used for more concentrated electrolytes generally when the target metal concentration is greater than 10 g/L. The emewPlate cell is often used for recovering copper, nickel and tin cathode in a variety of applications including mining, refining, and recycling. The emewPlate cells can also be paired with solvent extraction (SX) and ion exchange (IX) when pre-concentration of the target metal is necessary.

emew cell

Metal cathode is easily harvested by removing the upper end cap and using the specially designed harvester head and an overhead hoist. The reusable stainless steel starter sheet releases from the metal tube and is inserted back into the cell for the next plating cycle. This entire process typically takes as little as 30-60 seconds per cell. A cathode can weigh as much as 25 kg or approximately 50 lbs when harvested. The production rate of a single emewPlate cell can be as high as 15 kg/d depending on the metal and current density utilized.

emewPowder

The fully automated emewPowder cells use the same basic philosophy as emewPlate cells, however, they are designed to produce a metal powder.  The emewPowder cells generally operate at lower target metal concentrations (<5 g/L), higher current density and lower flow rate than their plating cell counterparts.  The metal powder formed on the cathode surface is automatically harvested using a flush-through methodology.  The closed nature of these cells coupled with automated flushing makes them ideally suited for precious metals applications such as silver, silver-gold and palladium.  Having a single collection point for the precious metal enhances security, reduces losses and facilitates metallurgical accounting.  In addition to precious metals, emewPowder systems are also used to produce specialty powders such as electrolytic copper and nickel powders, as well as bismuth and copper arsenide.

silver-powder

emewPolish

Direct electrowinning is pushed to the extreme with emewPolish. Using the same concept of high-efficiency emew electrowinning equipped with a sophisticated, proprietary high surface area cathode, this type of emew cell can recover metals down to less than 5ppm. Not possible with conventional electrowinning technology, the emewPolish cell is ideal for recovering metals from dilute concentration bleed streams, wastewater or any industrial process stream with low metals concentration.  

Applications for emewPolish include:

  • Silver refineries looking for an alternative to AgCl to treat bleed streams and spent electrolyte
  • Zinc refineries looking to minimize zinc dust usage to remove copper, cadmium, bismuth and others during zinc electrolyte purification
  • Any industrial wastewater that is too dilute to be treated by conventional means
emew polish electrowinning

emewClean

A unique fusion of emew cell designs, emewClean is specifically formulated for environmental applications.  This proprietary hybrid technology uses emew high surface area ‘3D’ cathode in combination with emewPlate technology to recover metals from dilute streams and produce high purity cathode.  This innovative, additive approach further expands the capability of emew electrowinning technology so that the sum truly is greater than the individual components.  The result is an advanced metal recovery system that can recover metals to less than 5ppm while also producing cathode for reuse or sale.  

Applications for emewClean include:

  • Copper waste from semiconductor fabrication plants
  • Rinse baths and drag out from electroplating facilities
  • Any industrial wastewater that is too dilute to be treated by conventional means
electrowinning for environmental applications