Rusal has commissioned the first electrolyzer with inert anodes. This event paves the way for replacing the EcoSoderberg technology, which is used by the largest aluminum plants in Russia – Bratsk, Irkutsk, Krasnoyarsk and others. The new technology not only nullifies greenhouse gas emissions, but also makes aluminum production a source of pure oxygen, the company said.
The traditional Soderberg technology has been used for over a hundred years. It was this technology that made it possible to establish mass production of aluminum and made the metal accessible. The carbon anode is constantly fed into the electrolyzer, self-ignites and serves as a current conductor. In the 1960s, plants were built using this technology, which ensured the USSR's world leadership in the production of "winged metal".
Scientists have consistently improved the classical technology, creating EcoSoderberg: reduced emissions of harmful substances, developed environmentally friendly petroleum pitch instead of coal pitch, introduced gas treatment that captures 99% of gases, and computer monitoring that halved the depressurization of electrolyzers.
A more environmentally friendly alternative is the baked anode technology, where harmful substances are burned in furnaces. The Sayansk, Khakass, Boguchansk and Taishet plants operate on it.
Both of these technologies have one thing in common: carbon anodes release CO₂ when reacting with oxygen. Inert anodes fundamentally change the process. They do not react, and about 900 kg of pure oxygen is released during the production of a ton of aluminum. No greenhouse gases.
Since 2017, Rusal has been testing the new technology and has achieved stable production of commercial aluminum of the highest grade (A7). Over the years of testing, 6,000 tons of such metal have been produced and shipped to customers. The company is starting industrial implementation.