Traditional off-season nonferrous metal aluminum

I. Complete industrial chain: China factory

China is the first big industrial country with a complete aluminum industrial chain in the world. From upstream bauxite mining, alumina smelting, electrolytic aluminum smelting, to downstream primary aluminum processing, to downstream aluminum deep processing in all walks of life, and subsequent application and consumption, except for upstream bauxite reserves, the capacity and output of other links are the highest in the world.

2. Bauxite: The peak of import dependence has passed.

Composition and quality standard of bauxite

Because of its active chemical properties, aluminum exists only in a combined state in nature. Aluminum minerals rarely form industrial deposits in pure state, but all coexist with other gangue and minerals. Bauxite is an industrial ore, which is mainly composed of gibbsite, diaspore or diaspore. According to the main components, bauxite can be divided into three types: gibbsite, diaspore and diaspore.

Bauxite contains as many as 42 elements, the main component is alumina and its hydrate, and the content is between 30% and 70%. It also contains silicon oxide, iron oxide, titanium dioxide, a small amount of calcium carbonate and impurities such as magnesium carbonate, sodium, gallium, vanadium, chromium, sulfur, phosphorus, fluorine, zinc and organic matter. Bauxite is divided into six grades according to its chemical composition, alumina content and mineral type. The quality standard refers to YB 123-62, as shown in the following table:

Global bauxite reserves distribution

According to the data of USGS, in 2022, the global bauxite basic resource reserves were 31.300 million tons, the output was close to 3.7 billion tons, and the basic resource retention period was close to 1.000 years.

From the perspective of global bauxite reserves distribution structure, Guinea's reserves rank first, and Guinea's bauxite basic resources reserves are 7.4 billion tons, accounting for 23.62% of the global bauxite basic reserves. Vietnam has the second largest reserves, with 5.8 billion tons of bauxite resources. 18.51%; Australia's reserves rank third, reaching16.28%; China has the seventh largest reserves, accounting for 2.27%.

Judging from the global bauxite reserves, China is not a country rich in bauxite resources. The bauxite reserves are not only far lower than those of Guinea, Australia and Brazil, but even lower than those of Vietnam and Indonesia in Asia.

Global classification of mineral deposits: most of them are of high grade.

The types of bauxite deposits in the world can usually be divided into two types: laterite type and sedimentary type. Its main components, physical and chemical characteristics, reserves and distribution are shown in the following table:

The difficulty of bauxite smelting is from low to high: gibbsite type, diaspore type and diaspore type. It can be found from the global data that most of the deposits are lateritic bauxite, belonging to gibbsite type and diaspore type, accounting for 88%, that is, high-grade mines.

Bauxite in China is mainly the third kind, which can only be dissolved under high temperature and high pressure. It is the most difficult to smelt, accounting for more than 99% of the total resources in China, while gibbsite bauxite is less than 1%, with low grade and small scale.

Distribution of bauxite reserves and grade in China: mixed feelings.

The proven reserves of bauxite in China are 765,438+tons, ranking seventh in the world, accounting for 2.27%, and the resource abundance is at a medium level.

Bauxite resources in China are concentrated, mainly in Guangxi, Henan, Guizhou and Shanxi provinces, with total reserves accounting for 9 1.9% of the total reserves in China. Guangxi has the most bauxite resources, accounting for 30% of the national reserves. Henan, Guizhou and Shanxi followed closely, with 24.43% in Henan, 24. 10% in Guizhou and 3.37% in Shanxi. The remaining six provinces, autonomous regions and municipalities with bauxite account for only 8. 1% of the total reserves in China.

Bauxite in China has low Al-Si ratio, mostly high Al (Al2O3 is more than 60%), high Si (SiO2 is between 5% ~ 15%) and low Fe (Fe2O3 is less than 10%). The ore body is thin and the grade fluctuates greatly. There are few bauxite resources suitable for economic development and utilization.

Global bauxite production distribution: relatively concentrated

According to iFind data, the global bauxite production increased from 245 million tons in 20 14 to 380 million tons in 2022.

From the distribution pattern of output in 2022, the global bauxite output is mainly concentrated in Australia, China and Guinea, and the output of the three countries accounts for 72.63% of the world.

Although China's bauxite reserves rank seventh in the world, the output of bauxite in 2022 is about 900 million tons, accounting for 23.68%, ranking second in the world. Australia's output is about 654.38 billion tons, ranking first in the world, accounting for 26.32%; The output of bauxite in Guinea is about 86 million tons, accounting for 22.63%, ranking third in the world. The output of Brazil, Indonesia and India is 33 million tons, 0.2 1 100 million tons and 0.10.700 million tons respectively, ranking fourth, fifth and sixth in the world.

China bauxite imports are increasing year by year.

Due to multiple constraints such as relatively limited resource reserves, unfavorable sintering grade and quality, and rising mining cost, domestic dependence on imported ore has increased year by year.

From the perspective of import sources, the import volume of Guinean minerals has increased year by year, accounting for more than 50% since 202 1; Since 2020, the import volume of Australian mines has been decreasing year by year; In recent years, the import volume from mines in Indonesia has remained at around 20 million tons. The proportion of these three aluminum resource countries in China's total imports has steadily increased, reaching 99.48% in 2022.

Bauxite-Overview

The global and China reserves are considerable, and the basic resources have a retention period of 100 years, far exceeding the upstream commodities such as copper and crude oil; 88% of the mineral resources in the world are high-grade, and the high-grade minerals in China's reserves are less than1%; China's import volume ranks first in the world, and its output also ranks among the top in the world. With the theme of environmental protection and double carbon, the space above the output is limited; According to China's import data, Australia, Guinea and Indonesia account for more than 99% of the imported resources. With the decrease of Australian imports year by year and the policy risk of Indonesian ban on bauxite export, China's dependence on Guinean ore imports is becoming more and more obvious.

Three. Alumina: Overcapacity can be exported.

Metallurgical grade alumina: 90%

Alumina can be divided into metallurgical grade alumina and non-metallurgical grade alumina according to different production uses. More than 90% of alumina in the world is metallurgical grade alumina. 95% of alumina is smelted from bauxite. Metallurgical grade alumina is used to produce metallic aluminum by molten salt electrolysis, and it is the main raw material for electrolytic aluminum production.

Alumina contains a variety of metal oxides, and these metals will first precipitate at the cathode during electrolysis, which will reduce the quality of aluminum. Therefore, alumina used in electrolytic aluminum smelting must have high purity and its impurity content should be as low as possible. The National Technical Committee for Standardization of Nonferrous Metals has stipulated the industry standard of metallurgical grade alumina, in which metallurgical grade alumina is divided into three grades according to chemical composition and physical properties, and the division standard is as follows:

The alumina mentioned below refers to metallurgical grade alumina.

Smelting process: Bayer process is mostly used.

The smelting process of alumina can be roughly divided into sintering process, Bayer process and sintering-Bayer combined process. At present, sintering method has been rarely used, and Bayer process is the mainstream smelting method.

Bayer process: alumina is dissolved in bauxite with caustic soda solution to prepare sodium aluminate solution; Al (OH) 3 was separated from the solution by cooling the solution, adding seed crystals and increasing stirring. The decomposed mother liquor is evaporated to re-dissolve a new batch of bauxite, and the remaining residue forms red mud. The dissolution process is carried out under heating and pressure, which is equivalent to the recycling of caustic soda mother liquor. The obtained Al(OH)3 was washed and calcined to obtain alumina.

Sintering method: soda ash and limestone are mixed into the furnace charge and sintered at high temperature to obtain calcium silicate, sodium aluminate and sodium ferrite; The sinter product is dissolved by dilute alkali liquor, sodium aluminate is dissolve, alkali is released by sodium ferrite water interpretation, and iron oxide enters that red mud together with calcium orthosilicate in the form of hydrate, and finally a sodium aluminate solution is obtained; The subsequent process is the same as Bayer process.

Bayer process has low cost, and the mother liquor can be recycled, which requires high grade bauxite. The specific data is the ratio of aluminum to silicon. The ore with low Al-Si ratio not only consumes a lot of caustic soda, but also it is difficult to obtain pure alumina directly by Bayer process, so sintering process is needed. In view of the large proportion of high-grade rich ore in the world, Bayer process is the most smelting process.

Alumina cost structure

According to the production process of alumina, the production cost of alumina mainly includes bauxite, limestone, caustic soda and other raw materials, power consumption, steam consumption, coke and other fuel and power costs, as well as other expenses such as labor, manufacturing and management. To produce 1 ton alumina (the amount of bauxite required to produce 1 ton alumina varies greatly with different grades) requires about 2. 1-2.7 tons of bauxite, 0.3-0.5 tons of coal and 0. 12-0. 14 tons. According to the latest data, the cost proportion distribution is as follows:

The data show that bauxite, caustic soda and power consumption account for 62. 1 1% of the total cost.

Global alumina production distribution: global production depends on Asia, and Asian production depends on China.

According to the global output data from 20 14 to 2022, the output of China, Africa and Asia (except China) maintained steady growth, with the same direction as the global total output and obvious trend; At the same time, the output of Oceania and South America is also considerable, and the output is relatively stable;

As far as the country is concerned, China is far ahead, while the output of Australia and Brazil is relatively stable.

From the distribution of alumina output and proportion in 2022, China's output accounted for 54.29%, ranking first; Australia ranked second, accounting for14.29%; Then it is Brazil's 7.86%, India's 5.29% and Russia's 2.2 1%.

Distribution of alumina production capacity in China: Shandong and Shanxi rank first.

During 20 1 1-2022, the alumina production capacity in China has been growing steadily, reaching 95 million tons in 2022, except for a short decline in 2020. Among them, Shandong and Shanxi have long been in the top two provinces with stable production capacity, accounting for nearly 60% of the total.

The production capacity data of each province in 2022 shows that Shandong and Shanxi rank in the echelon of more than 25 million tons, accounting for 57.92% of the total; Guangxi and Henan rank in the echelon of130,000 tons, accounting for 28.74% in total; Guizhou, Chongqing, Inner Mongolia, and Yunnan are in the echelon below100000 tons, accounting for 13.33%.

Distribution of alumina production in China: consistent with the distribution of production capacity.

The production trend of alumina in China is consistent with the capacity trend. Among them, Shandong and Shanxi have been in the first two provinces for a long time, and the output has been relatively stable since 20 17, accounting for nearly 60% of the total.

Judging from the output data in 2022, Shandong's output is more than 26 million tons, ranking first for a long time; Shanxi's output is about 20 million tons, ranking second, with the first two accounting for 57.25%; The output of Guangxi is also above100000 tons, accounting for 15.70%, and it is increasing year by year. Henan's output is relatively stable, always fluctuating around 6.5438+million tons, accounting for 654.38+02.28%; Other major producing provinces are all below100000 tons.

Utilization ratio of alumina production capacity in China: considerable supply elasticity.

Judging from the capacity utilization rate in 20 1 1-2022, except for 90% in 20 17, all the other years are below 88%; Since 20 17, if the epidemic situation is excluded, the utilization rate has decreased from the trend, but the total production capacity has increased. At the same time, combined with the simple characteristics of alumina smelting process, it can be started and stopped at any time, so the supply elasticity of alumina in China is considerable at present. Judging from the utilization rate of several main producing areas, Yunnan is running at full capacity, Shandong is above 90% all the year round, Guangxi and Guizhou are relatively stable above 80%, Henan, Shanxi and Inner Mongolia are decreasing year by year, and Chongqing is increasing year by year.

China's alumina overcapacity: the export model may be doomed to failure.

According to the SMM data in the above figure, from 20 14 to 2022, China's alumina net import and supply-demand balance data show that the output has been rising, the net import has slowed down, and the supply-demand balance has gradually changed from a gap to a surplus, and the surplus is still increasing.

According to the data of the National Bureau of Statistics and the General Administration of Customs in the above figure, from the data of China's alumina net import and supply-demand balance in 20 14-2022, the state of alumina surplus is more obvious.

From the data of total alumina production capacity, total electrolytic aluminum production capacity and their respective operating rates, the growth rate of electrolytic aluminum production capacity is much less than that of alumina, but the operating rate is obviously higher than that of electrolytic aluminum. Combined with the proportional relationship with alumina in electrolytic aluminum smelting, it can also be seen from the perspective of productivity that the excess state of alumina is fermentation.

20 14-2022, except 20 18, the export volume is less than the import volume, showing a net import state; The number of imports and exports is getting closer and closer, imports are decreasing and exports are increasing; The import and export volume is insignificant compared with the current domestic capacity and output; Combined with domestic alumina production capacity and electrolytic aluminum production capacity ceiling, the future alumina export pattern may be doomed.

Four. Electrolytic aluminum: the demand for metal in the future can be expected.

1. melting process: molten salt electrolysis.

The production process of aluminum electrolysis is divided into three stages: roasting, start-up and normal production, in which roasting and start-up take several days or more, and its quality has a great influence on the normal production and the service life of the electrolyzer in the future. Roasting: The main purpose of roasting the electrolyzer is to dry the furnace body, make the electrolyzer reach the operating temperature of 930℃~970℃, and prevent the molten electrolyte added when the electrolyzer is started from solidifying, which usually takes 4~8 days. Start-up: After roasting, cryolite and other solvents are melted to form the molten electrolyte needed for aluminum electrolysis, and at the same time, the furnace lining of the heating furnace is further heated to clean up the carbon slag, so that the main technical parameters of the electrolytic cell are within the range required for electrolysis. Normal production: In a high-temperature electrolytic cell at 930℃~970℃, using 1.92 ~ 1.94 tons of alumina as raw material, forming a molten electrolyte with fluoride solvents such as cryolite and aluminum fluoride, introducing 1.35 million kW·h direct current into the electrolytic cell, and performing electrochemical reaction at the cathode and anode. The density of electrolyte formed by melting alumina in cryolite is about 2. 1g/cm_, and the density of aluminum liquid is 2.3g/cm_. Because of the density difference, the aluminum liquid is layered up and down. Aluminum liquid is deposited on the bottom of the electrolytic cell, pumped out by vacuum lifting, purified and filtered to obtain primary aluminum 1t with purity of 99.5%~99.85%.

The smelting process of electrolytic aluminum belongs to heavy fixed assets investment. In the daily production process, except for irresistible factors such as maintenance, the continuous production process will not stop, and the cost of restarting the electrolyzer every time is high and the service life of the electrolyzer will be affected.

2. The cost structure of electrolytic aluminum

Smelting 1 ton electrolytic aluminum requires about 1.93 tons of alumina, 0.50 tons of prebaked anode, 20kg of aluminum fluoride, 10kg of cryolite and13500 kw h h dc. According to the latest data, the cost distribution is as follows, in which alumina, electricity and prebaked anode are the main costs, accounting for 365,438+0.68%, 365,438+0.34% and 65,438+03.94% of the total cost respectively, totaling 76.97%.

3. Distribution of global electrolytic aluminum production: China ranks first.

China is the largest producer of electrolytic aluminum in the world. According to iFind data, in 2022, the global output of electrolytic aluminum was 68.486 million tons, and that of China was 40.43 million tons, accounting for 59.03% of the global output. Since 20 13, China's electrolytic aluminum production has accounted for more than 50% of the world's electrolytic aluminum production. Except the proportion of 20 19 decreased, it kept increasing in other years, reaching 59% in 2022.

According to the data of output distribution, except China, the output of the Gulf region, Asia (except China), Russian, Eastern Europe and North America is relatively stable.

4. Distribution of electrolytic aluminum production capacity in China: "Aluminum moves from north to south".

China's electrolytic aluminum production capacity is relatively concentrated. According to Aladdin's data in 2022, the total electrolytic aluminum production capacity in Shandong (8.09 million tons), Xinjiang (6.54 million tons), Inner Mongolia (66.5438+0.9 million tons), Yunnan (4.95 million tons) and Guangxi (2.83 million tons) accounts for about 67.6% of the national production capacity. Among them, Xinjiang and Inner Mongolia are rich in coal resources, smelters can enjoy low-cost thermal power, Guangxi and Yunnan are rich in water resources, smelters can enjoy low-cost hydropower, and Shandong smelters enjoy a certain electricity price subsidy policy, which essentially determines the distribution of production capacity.

With the continuous promotion of "carbon dioxide emission peak" and "carbon neutrality", the upper limit of electrolytic aluminum production capacity in China has been determined. According to the data, since 20 19 production capacity plummeted, China's electrolytic aluminum production capacity has been slowly recovering, but the growth rate is obviously slower than before.

At the same time, the national electrolytic aluminum production capacity has a trend of "aluminum moving north to south". Limited by environmental protection and carbon emissions, the electrolytic aluminum production capacity in the north is gradually transferred to the water-rich provinces in the south. In fact, this process has been accelerated. As can be seen from the data, the production capacity of Shandong, Xinjiang and Henan provinces decreased significantly, while the production capacity of Yunnan and Guangxi increased significantly. The production capacity of thermal power-electrolytic aluminum is decreasing year by year, and the production capacity of hydropower-electrolytic aluminum is increasing year by year, and the proportion is also increasing year by year.

5. Utilization ratio of electrolytic aluminum production capacity in China: the supply elasticity is not great.

According to the utilization data of electrolytic aluminum production capacity in China, from 20 15 to 2022, the utilization rate is gradually increasing. From 20 19, the utilization rate was above 88%, and from 202 1, it increased to above 90%.

Judging from the utilization rate of main producing areas, except Guangxi, the utilization rate of other producing areas remains at a high level, and the room for improvement is limited. Considering that the electrolytic aluminum production capacity in Guangxi is at a medium level in the whole country, the electrolytic aluminum smelting process belongs to heavy fixed assets investment, and the domestic supply elasticity of electrolytic aluminum is limited in the short term.

6. Upper limit of electrolytic aluminum production capacity of 45 million tons in China: the incremental space is limited.

Since 20 17, domestic policies have been tightening the control of electrolytic aluminum. The main restrictive measures include: first, strictly control the increase of production capacity, and new projects must be replaced or reduced by the same amount; Second, strengthen the management of self-owned power plants and strictly implement the ladder price policy; Third, intensify efforts to eliminate backward production capacity and promote the establishment of a green power production model. With the supply-side reform of non-ferrous metals industry and the deepening of double carbon policy, the total production capacity of domestic electrolytic aluminum industry has formed a total ceiling of 45 million tons.

In recent years, due to the tightening of policy-side control, the speed of capacity expansion has slowed down, but it still shows an upward trend after 20 19. At present, the total domestic production capacity has approached the red line value of 45 million tons. In May 2023, the total domestic electrolytic aluminum production capacity was 447 1. 1 10,000 tons, reaching 99.36% of the red line value. At present, the production capacity is 410.083 million tons, and the capacity utilization rate reaches 910.46%. The future incremental space is limited, and the overall supply of the industry is relatively rigid.

7. Thermal power approval is more difficult: actively limit the production capacity of electrolytic aluminum.

At present, China's power structure is still dominated by thermal power generation, which will account for more than 70% of the country's total power generation in 2022. At the same time, thermal power is also a key carbon emission industry. According to the statistics of power grid, the carbon emission of domestic power industry accounts for 465,438+0% of the total energy industry, of which thermal power is the most important source. Therefore, after the introduction of the "double carbon policy" in 2020, the difficulty of domestic thermal power approval has increased significantly. In 2022, the installed capacity of domestic thermal power increased by 447 1 10,000 kilowatts, down by 3.39% year-on-year, down by 2 1.0 1% compared with 2020.

Due to the high energy consumption and power consumption of electrolytic aluminum industry, the mainstream production mode still needs to provide power from its own thermal power plant. This model has entered a bottleneck period under the background of energy saving and carbon reduction, and it is difficult to improve the production capacity. Taking Tianshan Aluminum Company as an example, the original planned 10 350MW thermal power units were only completed in the end. Even though the company is located in Xinjiang, where the pressure of environmental impact assessment is relatively low, it is still greatly reduced compared with the original construction plan.

8. Import and export of electrolytic aluminum: the import window is gradually opened.

The import window of electrolytic aluminum in China is closed all the year round, and the import volume is small. However, in the long run, as the ceiling of production capacity approaches, imported aluminum ingots will grow steadily. Judging from the net import data in the second half of 2020, this trend has been reflected.

9. Downstream applications are extensive.

At present, the terminal demand of electrolytic aluminum is still dominated by the demand of traditional industries, among which the aluminum for construction, transportation, power electronics and packaging accounts for 28.75%, 22%, 17.23% and1.63% respectively, accounting for about 79.6 1% in total. With the rapid growth of new energy vehicles, photovoltaics and other industries,

10, future demand increment 1: new energy vehicles

Lightweight automobile is an important direction for the development of new energy automobile industry. The goal is to reduce the quality of the whole vehicle by various means on the premise of ensuring the performance of the vehicle and realizing cost control.

At present, the research direction of lightweight mainly includes the following three aspects: using lightweight materials, using lightweight technology and optimizing automobile structure, among which the most direct and effective way is to use lighter materials. Aluminum alloy material has low density, moderate strength and good corrosion resistance, and is the mainstream material for vehicle lightweight.

Traffic aluminum is an important part of primary aluminum terminal application, mainly used in automobile manufacturing. The domestic automobile market has gradually recovered, and the proportion of new energy vehicles has been increasing. In the second half of 2022, affected by the COVID-19 epidemic, domestic automobile sales declined to some extent. In June 2023, the monthly sales volume of domestic automobiles was 1.9762 million, the lowest since June 201July. After entering February, with the optimization of domestic epidemic prevention and control policies, the automobile market has been quickly repaired, and has now rebounded to the middle and high-end level in recent years. At the same time, the sales volume and sales proportion of new energy vehicles are also increasing year by year. According to the data from 20 14 to 2022, the proportion has increased from 0.32% to 25.64%, with a rapid growth rate, and there is still much room for improvement in the future.

1 1. Future demand increment II: photovoltaic modules

The main application fields of aluminum in photovoltaic industry are frames, supports and aluminum paste. Aluminum paste is mainly coated on the surface of the battery as cathode paste, and the dosage is relatively small; As a component for fixing and sealing the battery cell, the frame needs to protect the edge of the glass and strengthen the sealing of the component. At present, domestic enterprises generally adopt aluminum alloy as the material for manufacturing vehicle frames. Bracket is the supporting structure of the whole photovoltaic system. The mainstream material is hot-dip galvanized carbon steel or aluminum alloy. The domestic application is mainly steel structure, and the export components are mainly aluminum alloy. From the cost composition of photovoltaic modules, the frame and bracket account for 10%.

The main competitive material of aluminum in photovoltaic field is steel, but compared with aluminum, the two materials have many performance advantages, and the unit aluminum consumption of photovoltaic is expected to continue to increase in the future; Compared with steel, aluminum has better compatibility with photovoltaic glass, and can ensure synchronous deformation when experiencing external temperature changes. The machining accuracy of steel is low, and it is easy to produce local stress concentration in bad weather, which leads to the explosion of module board. In terms of quality, the weight per unit area of aluminum bracket is about 1.5kg, and that of steel bracket is 3.5kg. For the construction of roof distributed photovoltaic power station with low bearing capacity, the use of steel will undoubtedly increase the bearing risk; In addition, the corrosion resistance of aluminum alloy is obviously better than that of steel material in strong corrosive scenes such as wind, sand and water.

Under the goal of "double carbon", photovoltaic industry is the key support object in the field of power infrastructure construction in China, and it has developed rapidly in recent years. At present, China's photovoltaic industry has formed a complete industrial chain from silicon materials, silicon wafers, battery components, equipment manufacturing, whole machine installation and application. It is the world's largest producer and exporter of photovoltaic modules, and its annual export volume accounts for more than 60% of the total domestic output. Driven by multiple favorable factors such as policy support, financial subsidies and technological innovation, the domestic photovoltaic industry has developed rapidly. In 2022, the newly installed capacity of photovoltaics in China was 88 million kilowatts, a year-on-year increase of 60.35%.

In 20021year, the Central Committee and the State Council pointed out in the Opinions on Comprehensively, Accurately and Comprehensively Implementing the New Development Concept and Doing a Good Job in Carbon Neutralization of Peak Carbon Dioxide Emissions that by 2030, the total installed capacity of wind-photovoltaic power generation will reach1200 million KW, and by May 2023, the total installed capacity of wind-photovoltaic power generation will reach 830 million kW, so there is still much room for development in the future photovoltaic industry.

12. Future supply increment: recycled aluminum

Because of its wear resistance and corrosion resistance, aluminum and its alloys have very low loss during use and will not lose their basic characteristics after repeated recycling, so they have high recycling value. According to the data of International Aluminum Association, more than 70% of the 6,543.8+0.5 billion tons of aluminum produced in the world history is still in use, and the recovery rate of aluminum cans can reach more than 95%.

Recycled aluminum not only has obvious economic advantages, but also can effectively save natural resources and protect the ecological environment. Compared with primary aluminum production, recycled aluminum takes waste aluminum and waste aluminum alloy materials as raw materials, and after sorting, simple treatment, remelting and refining, it directly enters the aluminum processing link, which saves three processes of bauxite mining, alumina smelting and electrolytic aluminum smelting, reduces energy consumption by more than 95%, and has extremely high economic advantages. A large amount of red mud containing metal wastes will be produced in the process of alumina production. There is no suitable treatment at present. The accumulation of a large number of red mud seriously affects the ecological environment, while the production of recycled aluminum does not involve the production of red mud, which has a positive impact on environmental protection.

Developed countries such as Europe and America have experienced a long process of industrialization, and more waste aluminum has been accumulated in society, and a relatively complete aluminum recycling system has been established. According to the data of the International Aluminum Association and USGS, recycled aluminum in Europe accounts for about 60% of the total primary aluminum and recycled aluminum, and the United States accounts for 83%. The proportion of recycled aluminum in China is only 17%, which is not only far lower than developed countries such as Europe and America, but also lower than the global average of 34.3%, indicating that the output of recycled aluminum in China is still low compared with primary aluminum, and there is broad room for improvement in the future.