China’s evolving aluminium industry: The country has multiplied its annual output of primary aluminium, while realizing energy-saving and emission-reduction technologies.

The aluminium industry in China has developed alongside the country’s broader industrialization and technological transformation. Over the last decades, China has evolved into the world’s largest producer and consumer of aluminium. Since the 1980s, the Chinese aluminium industry has developed significantly in two aspects: One is the annual output of primary aluminium that has continuously risen from roughly 400,000 t in 1983 to 40.21m t in 2022, accounting for 58.8% of the total annual global output. Another aspect is the average total energy intensity (i.e. the average comprehensive AC power per ton of aluminium), which has consistently decreased over the past 40 years.

Aluminium in China: from catching up to global player

Over successive decades, advances in extraction, smelting, and processing technologies have significantly improved production capacity and efficiency. More recently, innovation in automation, energy optimization, and materials science has reshaped the industry, reflecting China’s growing emphasis on technological self-reliance, industrial upgrading, and the integration of aluminium into high-value and emerging applications. In China, the progress in aluminium industry and its energy-saving technologies can be divided into three stages:

·         Stage 1: the ‘catching up’ stage from the 1990s to the mid-2000s

·         Stage 2: new energy-saving and emission-reduction technologies from the mid-2000s to the mid-2010s

·         Stage 3: expanding on energy savings and carbon emissions reductions

Stage 1: new technology for potlines

In the 1980s, Soderberg cells with line current of about 60 kA were widely used in China, yet their production environment and operating indicators were far from satisfactory. In the 1980s, China introduced a Japanese 160 kA prebaked-anode aluminium reduction potline, indicating the start of the modern aluminium smelting with large-scale reduction cells in China. However, the introduced process used an outdated fixed-time feeding control model, high molecular ratio (around 2.8) and high anode effect coefficient (1.0~1.2), resulting in less-advanced technical and economic indexes with current efficiency of about 87% and DC power consumption at about 13,800kWh/t-Al.

Upgraded technology to compete globally 

Starting from the late 1980s, the former China National Nonferrous Metals Industry Corporation (later known as Aluminum Corporation of China, or Chalco) organized its affiliated enterprises, Central South University, and other research institutes to jointly work on upgrading the imported potline. A valuable innovation was an intelligent fuzzy control technology developed in the mid-to-late 1990s. This technology upgraded fixed-time feeding to point-feeding and converted the ‘high molecular ratio (around 2.8)-low current efficiency (above 87%)’ process to a ‘low molecular ratio (around 2.3)-high current efficiency (above 93%)’ process, thus leading to a reduction of DC power consumption of large-scale prebaked-anode cell to around 13200 kWh/t-Al, reaching global advanced level during the same period.

Reduced energy intensity

In addition, based on the developed technologies of process, control and physical field simulation, a series of 180~280 kA aluminium electrolytic cells have been further developed. Within a few years of this century, such large-scale cells, as well as their process and control technologies, were widely promoted and applied in China, and all Soderberg potlines were shut down or transformed into prebaked-anode potlines, propelling China's average energy intensity indicator into the global advanced rankings in the mid-2000s.

Stage 2: saving energy, reducing emissions

At this stage, Chalco increased the capacity of China’s large-scale prebaked-anode aluminium electrolysis to more than 500 kA, as well as developing new energy-saving and emission-reduction technologies in collaboration with universities such as Central South University and Northeastern University. By the mid-2000s, advanced enterprises had already raised the current efficiency indexes to 93~95% by improving current efficiency to achieve energy savings, approaching the theoretical limit value of industrial reduction cells, and China had thus turned its attention to how to achieve energy savings by reducing the cell voltage on the premise of maintaining high current efficiency.

Based on this, a novel low-voltage and high-efficiency energy-saving process with critical-stability control technology, which was first developed by Central South University, represented an advance. This technology was able to reduce the cell voltage from 4.1~4.3 V in the past to below 3.75~3.95 V with the current efficiency being unchanged, resulting in significant energy savings and thus being widely used and promoted. At this point, the design concept of China's aluminium reduction cell has also realized a transition to low-voltage energy-saving types, which play an important part in making China's energy intensity indicator into the global top rankings in the mid-2010s.

Stage 3: expanding efficiency and sustainability

Since the mid-2010s, China has upgraded the maximum capacity of aluminium potline over 600kA and consistently developed and applied new technologies related to energy savings and emission reduction. Among them, the key technology of green, low-carbon, digitized and intelligent aluminium electrolysis, developed by Chalco in conjunction with Central South University etc., is a representative new technology, which is of great significance in promoting the aluminium electrolysis industry to achieve further energy savings and carbon emission reduction as well as sustainable development. Its main innovations are as follows:

·         Key technology for intelligent optimized manufacturing of aluminium electrolysis based on distributed sensing and digital twin

·         Energy-saving technology for aluminium electrolysis based on steady flow and heat preservation

·         Technology for the preparation and application of carbon dusting-free prebaked anodes

·         Green and safe disposal technology for aluminium electrolysis pollutants

Today’s aluminium industry in China

All these developments enable China nowadays to compete on a global level. Even more so, China’s output of primary aluminium has multiplied over the past years, so that now the Asian country is producing the majority of the total global primary aluminium. In 2024, the country of China produced more primary aluminium than all other regions of the world combined.

More aluminium means more alumina

As China produces more primary aluminium, naturally the output of alumina has gone up in the same period of time. Alumina, or aluminium oxide (Al₂O₃), is a critical intermediate material in the aluminium value chain, serving as the primary raw input for aluminium metal production. As demand for aluminium grows across sectors such as transportation, construction, and renewable energy, secure and technologically advanced alumina refining has become essential to ensuring stable supply. 

China needs bauxite imports

Even before alumina in the aluminium process chain there is bauxite. China does have bauxite deposits, but they are limited in quality and unevenly distributed. China’s bauxite resources are mainly located in the provinces of Shanxi, Henan, Guangxi and Guizhou. Much of this bauxite is low- to medium-grade, which makes refining more complex and costly. As a result, despite having domestic bauxite, China relies heavily on imports – particularly from countries like Guinea, Australia, and Indonesia – to support its large alumina and aluminium production capacity. As aluminium demand rises, China’s bauxite imports also go up. In the first half of 2025, bauxite imports have gone up 34% compared to the same period in 2024. 

All eyes on China’s aluminium industry

The global aluminium industry closely watches China’s aluminium sector due to its dominant position as both the largest producer and consumer of aluminium worldwide. China’s rapid industrial growth, coupled with advances in production technology, has positioned the country as a key player in the global aluminium market, influencing pricing, supply chains, and innovation.

The ALUMINIUM China trade fair plays a significant role in this dynamic, serving as a major platform for international stakeholders to showcase new technologies, discuss market trends, and forge business connections. The event highlights China's pivotal role in shaping the future of the aluminium industry, while also providing a venue for global companies to understand the latest developments in production, sustainability, and the evolving demands of the aluminium market. ALUMINIUM China has celebrated its 20th anniversary in 2025, attracting global visitors to explore the chances that the Asian aluminium market has to offer. 

Technology that advanced China’s aluminium industry

Over the last decades, China’s industry made a lot of advancements in processes and technologies for the aluminium industry, particularly in aluminium smelting and the production of primary aluminium. State-of-the-art technologies have been developed in order to optimize production, save energy, and reduce emissions. 

Digital twin and distributed sensing in electrolysis

In response to the long-standing problem that the online signals collected by the control system were only two (cell voltage and line current), which makes it impossible to realize online sensing and fine regulation of the spatio-temporal distribution characteristics of large cell, the developed technology advanced the online distributed detection and sensing method of reduction cell. This technology solved the long-term issues plagued by the aluminium industry of accurate, reliable and low-cost on-line detection of distributed signals of anode current distribution, and innovatively extended the online detected signals from the traditional two kinds (two detecting points) to seven kinds (nearly 300 detecting points).

On this basis, digital twin, fine and zoned control of reduction cell as well as intelligent decision-making for smelting process were realized, leading to an increase in the uniformity of the alumina concentration in the whole cell by more than 80% and a reduction of the abnormal cell by more than 50%. This technology had a great impact on further reducing energy intensity and increasing labor productivity, while also providing technical support for the construction of digital and intelligent factory of aluminium electrolysis, leading the transition of the digitalization and intellectualization of aluminium reduction cells and the production process control from the era of ‘aggregate parameters’ to the era of ‘distributed parameters’.

Energy-saving technology 

Aiming at the problem that existing technologies for improving magnetohydrodynamic stability (MHD) in aluminium reduction cells are approaching their limit, new technology featured with highly conductive collecting bar (including steel conductivity enhancement and size optimization), regional current conduction strengthening, thermal regulation and energy balance optimization was developed. This technology has not only achieved great breakthroughs in improving MHD, but also in optimizing flow field of aluminium liquid and thermal field of the cell, as well as reducing the cathode voltage drop, which provide new technical supports for efficiency promoting and energy saving at low voltage in aluminium reduction cells.

Realisation of dusting-free operation for electrolysis

In the past ten years, China has faced the environment and conditions that are unfavourable to the production of high-quality anodes and the stable operation of reduction cells. On the one hand, the supply of petroleum coke was gradually deteriorating, which has adversely affected on the quality of anodes. On the other hand, about half of the alumina used for the aluminium production in China was produced from gradually-deteriorating bauxite, which results in the increase of content of impurities in alumina, and, thus, impurities like lithium and potassium were prone to accumulating in the cell to form a complex electrolyte composition that was very unfavourable to the running stability of reduction cells. The overlap of the two named factors above makes it difficult to separate carbon particles detached from the anode from the electrolyte, which seriously affects the cell operation. Thus, the developed technology can not only solve the problem of producing high-quality anode from low-quality and complicated petroleum coke, but also realize dusting-free operation for aluminium electrolysis.

Green and safe disposal technology 

This technology solves a number of technical problems in the green, safe disposal and resourceful use of aluminium electrolysis overhaul slag and secondary aluminium ash, through which the contained toxic substances have realized safe and rapid leaching from slags and have been rendered completely harmless, allowing the tailing to be turned into building materials. The products and tailings after disposal meet the requirements of the national mandatory standard GB-5085.3 ‘Identification standards for hazardous wastes-Identification for extraction toxicity’, in which the leaching concentration of fluoride and cyanide is less than 9.0 mg/L and 0.03 mg/L, respectively.

For the secondary aluminium ash, the enhanced hydrolysis leaching and graded gas released and recycling technology has been developed, with the decomposition rate of AlN being greater than 95%, and the recovery rate of soluble salt, combustible gas and ammonia being greater than 98%. The alumina content of the leaching tailings was greater than 70%, with the reactivity and leaching toxicity meeting the requirements of national mandatory standards. After directional transformation, it can be used for the production of refractory materials, refining agent for steel-making, calcium aluminate powder and other aluminium-based products. Most of all, zero waste discharge is realized during the disposal and utilisation process, and all environmental and quality indicators meet the requirements of relevant standards. (tp)

Source：INTERNATIONAL ALUMINIUM JOURNAL