The Core Value And Technical Composition Of Titanium Anodes in The Chlor-Alkali Industry

The Core Value and Technical Composition of Titanium Anodes in the Chlor-Alkali Industry

In the chlor-alkali industry, the core process is the electrolysis of saturated brine to produce chlorine, caustic soda, and hydrogen. The anode, as a key component of the electrolysis process, directly determines energy consumption, efficiency, and operational stability. The titanium anode, commonly known as a Dimensionally Stable Anode (DSA), has completely replaced traditional graphite anodes as the industry standard since the 1970s due to its revolutionary technological advancements.

The essence of a titanium anode is a composite electrode material. Its substrate is made from industrial pure titanium (grades TA1/TA2), formed into a mesh or plate to provide mechanical support and conductivity. The functional core is a micron-level electrocatalytic active coating loaded onto the titanium substrate surface through processes like thermal decomposition oxidation. This coating primarily consists of precious metal oxides, most commonly ruthenium-titanium based systems (e.g., RuO₂-TiO₂) and iridium-tantalum based systems (e.g., IrO₂-Ta₂O₅).

This structure provides fundamental advantages. First, the titanium substrate passivates under electrolysis conditions, suffering minimal dimensional change. This ensures a long-term stable electrode gap in the electrolyzer, preventing the continuous voltage increase caused by electrode consumption. Second, the active coating exhibits excellent catalytic properties for the chlorine evolution reaction, significantly reducing the electrochemical overpotential and thereby achieving substantial savings in DC power consumption. Finally, its high catalytic selectivity effectively suppresses the oxygen evolution side reaction. This not only improves the purity of the chlorine product but also extends its service life from a few months for graphite anodes to six years or more. Currently, conventional membrane cell processes predominantly use the cost-effective ruthenium-titanium based coating, while processes with strong oxygen evolution side reactions (e.g., those paired with oxygen-depolarized cathode technology, or chlorate production) must use the more stable iridium-tantalum based coating.