Firstly, detailed explanation of titanium anode:
The titanium anode is called a 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 electrical conductivity.
Titanium anode classification:
According to the anodic precipitation gas in the electrochemical reaction, the chlorine anode is separated, such as the lanthanide-coated titanium electrode: the oxidized anode is called an oxygen evolution anode, such as a lanthanide-coated titanium electrode and a platinum-titanium mesh/plate.
Chlorine anode (lanthanide coating titanium pole):
High chloride ion content in the electrolyte: generally in the hydrochloric acid environment and electrolysis of seawater, electrolysis of saline environment. Such as Ir-Ru titanium anode, bismuth tin titanium anode.
Oxygen evolution anode (lanthanide coated titanium electrode):
The electrolyte is generally in a sulfuric acid environment.Ir-Ta anode, bismuth tin anode, high Ir anode.
Platinum anode (platinum titanium mesh / platinum titanium plate):
Titanium is the substrate. The surface is plated with precious metal platinum, and the thickness of the coating is generally 1-5 um (micrometers). Platinum titanium mesh mesh specifications are generally 12.7 * 4.5mm or 6 * 3.5mm.
Secondly, the advantages of titanium anode:
At present, domestic titanium anodes are mainly brushed. Such an electrode has a very wide range of applications, and the titanium anode is also known as a DSA anode because of its light and flexible manufacturing process, and has the following advantages over the superior performance of the same anode titanium anode;
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 improve the purity of metal products.
5. The current density is high, the overpotential is small, and the electrode has high catalytic activity, which can effectively capture 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 manufacture and can be highly accurate.
8. The titanium matrix can be reused.
9. The lower overpotential characteristics, the bubbles between the electrodes and the electrodes are easily eliminated, which can effectively reduce the voltage of the electrolytic cell.
The electrode extracting metal is a method for reducing the metal ions to be extracted in the leached and purified electrolyte in the cathode to obtain a pure metal. The Ti substrate and the noble metal and/or noble metal oxide coated thereon are electrochemically active. Layer composition.
In electrolytic metallurgy, it can replace the conventional lead alloy anode, under the same conditions, the voltage can be reduced, and the power consumption can be saved. For example, electrolysis of zinc has always used a lead alloy anode containing a small amount of silver, strontium or calcium. The following problems often occur: the lead alloy electrode is unstable in size; the oxygen evolution potential is too high (about 800 mV); corrosion occurs during anodic polarization; lead ions are dissolved in the electrolyte, deposited on the cathode, contaminating the metal zinc, affecting product quality . Titanium anodes for electrowinning metals can overcome the drawbacks of lead alloy anodes, and are suitable for high current density operation and narrow pole spacing electrical conditions; not only for sulfate systems, but also for chloride systems and sulfates and chlorides. Mixed system.
Thirdly, the role of metal oxide coating on the titanium anode:
By covering different coatings, the electrical conductivity and electrocatalytic activity are enhanced, the electrolysis reaction process is promoted, and the service life of the anode in different use environments is prolonged to achieve the intended use effect.
Thickness of metal oxide coating on titanium anode:
The electrocatalytic reaction is mainly the precious metal in the coating. Only the precious metal content can meet the requirements of use to ensure the normal operation of the anode product. The thickness is only an appearance, which is mainly determined by the number of passes of the brush and the concentration of the solvent, and the amount of precious metal. There is no direct contact, and a thick coating is more likely to fall off.