Recently, the "Aluminum Electrolysis Energy-saving and Carbon-reducing Technology Based on Reducing Perfluorocarbon Emissions" led by Yuefeng Aluminum Research Institute has solved the common industry problem of high perfluorocarbon emission intensity when using domestic alumina in large-scale aluminum electrolysis cells. This technology has reduced the equivalent carbon dioxide emission intensity of aluminum electrolysis per ton of aluminum to below 0.26 tons, with a reduction rate of over 77%, marking a significant breakthrough in the green transformation and deep carbon reduction of the aluminum industry in China.
Perfluorocarbon is a strong greenhouse gas produced during aluminum electrolysis, with a global warming potential of over 6,500 times that of carbon dioxide.
Due to the high content of lithium, potassium, and other elements in domestic alumina, it lowers the initial crystallization temperature of the electrolyte by more than 30°C, seriously affecting the dissolution of alumina. Moreover, as electrolysis cells become larger, the uneven distribution of alumina concentration within the cells becomes more prominent, leading to frequent local anode effects and a significant increase in perfluorocarbon emissions. As the world's largest producer of electrolytic aluminum, the industry's perfluorocarbon emission intensity was previously higher than the global average due to these factors.
To address this common industry problem, the research team of Yuefeng Aluminum Research Institute started from the mechanism of perfluorocarbon generation and conducted continuous research for nearly two decades. They were the first in the world to reveal the generation mechanism of non-anode effect perfluorocarbons and identified that "local low alumina concentration" was the key factor causing continuous perfluorocarbon emissions. They broke through the traditional understanding that only increasing the average concentration ignored the low local concentration.
The research team of Yuefeng Aluminum Research Institute combined reducing perfluorocarbon emissions with artificial intelligence and pioneered a three-dimensional integrated coupling technology of "differential control of electrolyte composition - balanced energy balance of electrolysis cell regions - precise control of alumina feeding". This technology inhibits anode effects from the source and reduces perfluorocarbon emissions. Among them, the differential control technology of electrolyte composition established a molecular ratio control model related to the content of each fluoride, which can customize the control of electrolyte composition based on the differences in raw materials of each enterprise, significantly improving the adaptability to complex electrolyte systems; the balanced energy balance technology optimizes the energy distribution in the cell to improve the solubility of alumina in the complex electrolyte, reducing the deviation of alumina concentration distribution by 48%; the precise control technology of alumina feeding achieved core control targets such as a shell-breaking penetration rate of ≥ 90% and a feeding deviation of ≤ 10%. The three technologies work together to ensure that the alumina concentration in each region of the cell remains within a safe range. "In simple terms, we have equipped the aluminum electrolysis cells with an 'intelligent brain', allowing alumina to 'dissolve evenly' and 'be consumed accurately' in the electrolyte, blocking the generation conditions of perfluorocarbons from the source." The project technical director said.
Currently, this technology has been applied in more than 20 electrolytic aluminum enterprises across the country, covering an output capacity of over 6 million tons. The actual application data shows that this technology has achieved significant environmental protection and economic benefits. The equivalent carbon dioxide emission intensity of perfluorocarbons has decreased from 1.12 tons per ton of aluminum to below 0.26 tons per ton of aluminum, with the average DC power consumption per ton of aluminum reduced by more than 47 kilowatt-hours. Since 2022, it has saved 1.133 billion kilowatt-hours of electricity and reduced 18.71 million tons of carbon dioxide emissions, generating an additional economic benefit of 1.146 billion yuan. This technology has been granted 29 invention patents and 2 utility model patents. The core patent "A Method for Reducing Perfluorocarbon Emissions in Aluminum Electrolysis" has completed patent layout in the United States, Norway, Canada, Russia, and the United Arab Emirates.
Industry experts believe that this achievement has opened up a new path for deep carbon reduction in green electricity aluminum. In the current context of increasingly strengthened green trade barriers globally, this self-controlled source reduction technology will provide important technical support for electrolytic aluminum enterprises to cope with carbon constraints, enhance the international competitiveness of China's aluminum industry, and promote the green and low-carbon transformation of the industry.
