English
The electrolytic cell for nickel electrowinninig contains a fairly high amount of chloride and will therefore require an electrode that is resistant to chlorine attack, as chlorine will be evolved at the anode. The complicating factor here is also the production of oxygen at the anode too. Most materials are resistant to either chlorine or oxygen, but not both, or at least not well. For this reason, inert or insoluble catalyst coated anodes applied on an inert substrate. Usually, the best bet is to use a layered inert anode material. The chlorine attack usually occurs on the substrate itself, so it should either have high chlorine over potential, it can be titanium (or tantalum) with a small layer of platinum electroplated to it. Then, the electrode substrate can be coated with an oxygen evolving catalyst, such as iridium dioxide or similar coatings. An excellent lifetime will be obtained in most of application, however care must be exercised not to allow the electrode to be cathodic, or the coating will be quickly lost.
Iridium oxide Coated Titanium Anode for Nickel Electrowinning Parameters:
Anode: Titanium Gr1/Gr2;
Coating: Iridium, tantalum, platinum + X;
Shape: Tubular, mesh, plate or customize;
Current Density: 300 - 500 A/m²;
Electrolyte solution: Sulfuric acid;
Operating Life: 5 years;
Warranty: ≥3 years.
Advantages:
Low cell voltage cuts cell energy consumption;
No pollution;
Less byproduct;
High corrosion stability.
Applications:
Electro winning of copper, cobalt, nickel, chromium, zinc and other metals;
Metal recovery systems;
Electro winning Pilot Plant.
UTron has developed a novel noble metal oxide coated titanium anode comprising nano iridium oxide in combination with amorphous tantalum oxide and other elements for nickel electrowinning. It can remarkable decrease cell voltage compared with traditional lead alloy anode, which can reduce the electric energy consumption in electro winning process. It gives additional merits in suppressing by products such as lead, MnOOH, or CoOOH on anode.
Conventional lead silver alloys are predominantly used in the zinc electrowinning, due to their cost efficiency and long-term stability at high current densities and in aggressive environments; however, their drawbacks include high over potential and the possibility of cathode contamination are worth considering. The Oxide Coated Catalytic Anodes are considered to improve cathodic zinc purity and decrease cell voltage during zinc electrowinning. Considering the Ti substrate and its coatings such as IrO2 and Ta2O5 coatings, the composites of OCAs have low over potentials 400–500 mV less than Pb-Ag anode.
The electrolytic cell for nickel electrowinninig contains a fairly high amount of chloride and will therefore require an electrode that is resistant to chlorine attack, as chlorine will be evolved at the anode. The complicating factor here is also the production of oxygen at the anode too. Most materials are resistant to either chlorine or oxygen, but not both, or at least not well. For this reason, inert or insoluble catalyst coated anodes applied on an inert substrate. Usually, the best bet is to use a layered inert anode material. The chlorine attack usually occurs on the substrate itself, so it should either have high chlorine over potential, it can be titanium (or tantalum) with a small layer of platinum electroplated to it. Then, the electrode substrate can be coated with an oxygen evolving catalyst, such as iridium dioxide or similar coatings. An excellent lifetime will be obtained in most of application, however care must be exercised not to allow the electrode to be cathodic, or the coating will be quickly lost.
Cylindrical electrowinning cell designs have been shown to significantly enhance mass transfer owing to high flow rates and a unique spiral flow within the cell.It proven to the advantages of increasing production capacity, reduction footprint, enhancing selectivity and recovery from lower concentrations than conventional technology. This technology has been widely employed in copper, zinc, nickel, cobalt electrowinning.
