Detailed explanation of titanium anode:
The full name of titanium anode is called titanium-based metal oxide coated titanium anode (MMO). Also called KSA anode. (Dimensional shape-stable anode). It uses titanium as the substrate and brushes the precious metal coating on the titanium substrate to make it have good electrocatalytic activity and conductivity.
Titanium anode classification:
According to the anode gas evolution in the electrochemical reaction to distinguish, chlorine precipitation is called chlorine evolution anode, such as ruthenium-coated titanium electrode: precipitation oxidation is called oxygen evolution anode, such as iridium-coated titanium electrode and platinum titanium mesh / plate .
Chlorine anode (ruthenium-coated titanium electrode):
High chloride ion content in the electrolyte: generally in hydrochloric acid environment and electrolyzed seawater, electrolyzed salt water environment. Such as ruthenium-iridium-titanium anode, ruthenium-iridium-tin-titanium anode.
Oxygen evolution anode (Iridium-coated titanium electrode):
The electrolyte is generally sulfuric acid environment. Iridium tantalum anode, iridium tantalum tin anode, high iridium anode.
Platinum-plated anode (platinum titanium mesh / platinum titanium plate):
Titanium is the base material. The surface is coated with precious metal platinum, and the thickness of the coating is generally 1-5um (micrometer). Platinum mesh mesh specifications are generally 12.7 * 4.5mm or 6 * 3.5mm.
The advantages of titanium anode:
At this stage, the domestic titanium anode is mainly brushed. Such electrodes have a very wide range of applications. Titanium anodes are also known as DSA anodes due to their light and flexible manufacturing process. Compared with similar anodes, titanium anodes have the following advantages;
- 1. The anode size is stable, and the distance between the electrodes does not change during the electrolysis process, which can ensure that the electrolysis operation is performed under the condition that the cell voltage is stable.
- 2. The working voltage is low, the power consumption is small, and the DC power consumption can be reduced by 10-20%.
- 3. Titanium anode has long working life and strong corrosion resistance.
- 4. It can overcome the dissolution problem of graphite anode and lead anode, avoid the pollution of electrolyte and cathode products, and thus can improve the purity of metal products.
- 5. High current density, small overpotential, high electrode catalytic activity, can effectively catch high production efficiency.
- 6. It can avoid the short-circuit problem after the lead anode is deformed and improve the current efficiency.
- 7. The shape is easy to produce and can be made with high precision.
- 8. The titanium substrate can be reused.
- 9. Low over-potential characteristics, the bubbles between the surface of the electrode and the electrode can be easily eliminated, which can effectively reduce the voltage of the electrolytic cell.
Electrodeposited metal extraction is a method for preparing pure metals by reducing metal ions to be extracted in the leached and purified electrolyte solution at the cathode. The Ti substrate and the precious metals and / or precious metal oxides coated thereon are electrochemical Active layer composition.
In electrolytic metallurgy, it can replace the conventional lead alloy anode. Under the same conditions, it can reduce the voltage and save power consumption. For example, electrolytic zinc production has always used lead alloy anodes containing small amounts of silver, antimony or calcium. The following problems often occur: the size of the lead alloy electrode is unstable; the oxygen evolution potential is too high (about 800mV); corrosion occurs when the anode is polarized; lead ions are dissolved in the electrolyte and deposited on the cathode, contaminating the metal zinc, affecting product quality . Titanium anodes for electrowinning metals can overcome the shortcomings of lead alloy anodes, and are suitable for high current density operation and narrow pole spacing electrowinning conditions; not only suitable for sulfate systems, but also suitable for chloride systems and sulfates and chlorides Mixed system.
The role of metal oxide coating on titanium anode:
By covering different coatings, it enhances the electrical conductivity and electrocatalytic activity, promotes the electrolytic reaction process and prolongs the service life of the anode in different use environments, and achieves the expected use effect.
Thickness of metal oxide coating on titanium anode:
The electrification catalytic reaction is mainly the precious metal in the coating. Only the precious metal content meets the requirements to ensure the normal operation of the anode product. The thickness is only an appearance, which is mainly determined by the number of brushing passes and the concentration of the solvent, and There is no direct connection, and the over-thick coating is easier to peel off.