Titanium anode is a titanium-based oxide coating anode. Its surface catalytic coating has a different oxygen evolution function and a different chlorine evolution function. The general electrode material should have good conductivity, a small distance change, high corrosion resistance, good mechanical strength and processing performance, a long life, a low cost, and good electrocatalytic performance on the electrode reaction. At the moment, titanium is the most capable of meeting the above comprehensive metal requirements, typically using industrial pure titanium Grade 1 or Grade 2.
Metal oxide coating has the following effects on titanium anodes: low resistivity, good electrical conductivity (titanium has poor electrical conductivity), chemical composition of precious metal coating stability, stable crystal structure, electrode size stability, good corrosion resistance, long life, good electric catalytic performance, reducing oxygen, chlorine overpotential, and saving power.
In the metallurgical industry, anodes are classified as soluble or insoluble.
During electrolysis, the soluble anode supplements metal ions while also conducting electricity, whereas the insoluble anode only conducts electricity. Graphite and lead anodes were the first insoluble anodes. In the 1970s, titanium anodes were used as a new technology in the electrolysis and electroplating industries.Insoluble anodes are currently classified into two types: chlorine anodes and oxygen anodes. Chlorine chromatography anode is primarily used for chloride electrolyte systems; the anode has chlorine gas released during the electroplating process, thus the name; oxygen evolution anode is primarily used for sulfate, nitrate, hydrocyanate, and other electrolytic liquid systems; the anode has oxygen released during the electroplating process, thus the name. Lead alloy anode oxygen evolution anode, titanium anode has oxygen evolution, chlorine evolution, or both functions depending on their surface catalytic coating.
Anodes made of lead and lead alloys
Lead alloy anodes are oxygen evolution anodes. The oxygen evolution reaction's electrolyte is sulfuric acid and sulfate, which are commonly used in electrolytic metallurgy. The geometric size of this type of anode will change during the electrolysis process. The lead anode matrix is first converted into lead sulfate and then into lead oxide during the electrolysis process. In sulfuric acid environments, lead sulfate acts as an insulator as well as a chemical barrier to protect the inner lead matrix.The outer layer of lead oxide serves as a practical electrode for the oxygen evolution reaction. Lead oxide has a very high oxygen evolution potential that increases rapidly with increasing current density. This property of a lead alloy anode is determined by the inherent properties of its outer material, lead oxide, which is a poor electrical conductor. Furthermore, during the electrolysis process, the electrochemical properties of the lead oxide anode structure are constantly attenuated, falling off to produce oxide layers of internal stress, Furthermore, as an intermediary lead sulfate is converted to lead oxide, the new outer oxide electric catalytic active substance, the inner layer of lead substrate by oxidation, The new lead sulfate intermediate protective layer is formed. As a result, during the electrolysis process, lead and its alloying elements are continuously dissolved and precipitated in the electrolyte, resulting in solution contamination (chemical precipitation in the solution) and cathodic product contamination (electrodeposition of pollutants on the cathode surface, and the purity of copper electrolysis cannot be well guaranteed).
Anode made of titanium
Because titanium anode does not suffer from mechanical size attenuation like graphite anode and lead alloy anode, it is also known as size stability anode. Titanium anodes have the following benefits: geometric stability; variety of geometric shapes; excellent electrochemical and chemical performance stability; excellent electrocatalytic active anode has low potential and is not sensitive to changes in circuit density. Energy savings, extended electrolyte service life; no maintenance; long life (very important); high cathode quality (no or very few impurities, uniform microstructure, such as electrolytic copper, zinc, nickel).Titanium anodes are a two-layer composite structure composed of a metal matrix and a coating on the matrix. The titanium matrix is a conductive body, and the coating serves as an electrochemical catalyst for the oxygen/chlorine evolution reaction. This coating has a low oxygen evolution/chlorine evolution potential, and the oxygen evolution/chlorine evolution potential almost does not change with current density. Titanium base conductive material is a permanent material with a long coating life and the ability to produce almost completely pure cathode products with no pollution.
