China should develop aluminum recycling industry b

2022-08-22
  • Detail

China should better and faster develop the aluminum recycling industry

since the beginning of the new century, in order to further make up for the shortage of China's mineral and metal resources and alleviate the tension between supply and demand, under the guidance of a series of national support and standardized industrial development policies, China's renewable metal industry has made full use of international resources for rapid development, with trade accounting for more than half of the global non-ferrous metal waste, and more than 80 countries or regions have transnational allocation of resources, A total of more than 100 million tons of copper and aluminum waste were imported, and nearly 70 million tons of recycled non-ferrous metal products were produced. Among them, recycled copper produced from imported copper containing waste accounts for more than 70% of the total; Recycled aluminum produced from imported aluminum containing waste accounts for nearly 55% of the total. It has achieved the phased goal of rapidly utilizing international non-ferrous metal waste resources to expand China's renewable non-ferrous metal industry, and made a positive contribution to the non-ferrous metal materials to meet the needs of economic and social development

Since last year, the state has further strengthened the construction of ecological civilization, comprehensively banned the entry of foreign garbage, and promoted the reform of solid waste import management system; Recently, the Sino US trade war has restricted the import of aluminum alloy waste, which has seriously affected enterprises that have long relied on imported waste for production. In the face of these challenges, we should recognize the supply pattern of the domestic aluminum alloy scrap market, correct the blurred vision clearly by improving the efficiency of resource utilization, eliminating the impact of the trade war, and find back the missed and wasted resources, so that more aluminum scrap resources can quickly return to production enterprises, so that China's renewable aluminum industry can turn from import driven development to self-sufficient and healthy development

aluminum alloy scrap market

aluminum can be recycled indefinitely, and the energy required for recycling aluminum is about 95% lower than that for producing raw aluminum, reducing emissions by more than 90%. Since the production of aluminum began in 1888, about 1 billion tons have been produced, 75% of which are still recycled. As aluminum is processed into consumer goods or industrial products according to market needs, aluminum waste is composed of "new" and "old" waste forms. Aluminum will produce new waste in the process of forging and casting products, and the old waste will be recycled from scrap products or all types of waste raw materials, which account for nearly 75% of the manufacturing cost. There is also a kind of garbage (aluminum ash) that is often ignored and doesn't feel very important

due to the high economic value of aluminum, the recovery rate of aluminum has been very high. The recovery rate of aluminum cans in the construction and transportation fields and the packaging industry can reach 95%. In addition, the recovery of foil in the packaging industry is also growing. In 2017, the total global aluminum output was 94.848 million tons, of which 30.986 million tons were produced from scrap metal aluminum (recycled aluminum or secondary aluminum), accounting for 32.7%, and 63.826 million tons were produced from alumina (primary aluminum), accounting for 67.3%

it is obvious that countries with high aluminum consumption are also the standards required for the flexible addition of Zu in the production of aluminum waste; I many countries, at present, the world's aluminum waste is mainly concentrated in the United States, the European Union and China; A large part of high-quality waste from Europe and the United States is recycled internally to manufacture new aluminum materials. Due to the relatively short service life of packaging and cars, the recovery rate and recovery speed of waste are fast, so the surplus part is exported. Previously, China was the main importer of broken automotive aluminum alloy waste from Europe and the United States

the United States is an area with a long history of aluminum production and consumption, and also an area rich in aluminum alloy scrap resources in the world. In addition to meeting the waste required for domestic secondary aluminum production, it also exports 2million tons of waste every year, accounting for one third of the total global waste supply. In 2016, the total consumption of aluminum in the United States was 9.538 million tons, including 5.325 million tons of recycled aluminum, accounting for 55.8% of the total consumption of aluminum. In 2016, the United States produced 6.508 million tons of recycled aluminum. Among them, 1.972 million tons were produced from new waste, accounting for 30.3%, and 4.536 million tons were produced from old waste, accounting for 69 The argument is very big 7%

EU - accounting for more than 15% of global aluminum consumption, aluminum consumption is mainly concentrated in Germany, Britain, France and Italy, which is the location of the world's largest automotive manufacturer Zui. The development of the global aluminum industry largely depends on this market. In 2016, the total consumption of metal aluminum in the EU was 10.231 million tons, including 4.62 million tons of recycled aluminum, accounting for 44.8% of the total metal consumption. In 2016, the EU produced 5.288 million tons of recycled aluminum. Among them, 1.767 million tons were produced from new waste, accounting for 33.4%, and 3.521 million tons were produced from old waste, accounting for 66.6%

China is the largest aluminum producer in the world, and its aluminum output has been ranking first in the world since 2001. In 2016, the output of primary aluminum accounted for 54.4% of the world, and the total aluminum consumption was 42.518 million tons, of which 9.952 million tons were recycled aluminum, accounting for 23.4% of the total metal consumption. In 2016, China produced 8.507 million tons of recycled aluminum. Among them, 3.06 million tons are produced from old waste, accounting for 36%, and 5.45 million tons are produced from new waste. The structural characteristics of electronic universal tensile machine account for 64%

ignored and forgotten facts

with the continuous increase of China's metal aluminum savings, China's aluminum alloy waste production is also increasing. Only from 2001 to 2016, China has produced 230 million tons of electrolytic aluminum, with a per capita consumption of 24 kg and a per capita reserve of 130 kg. The import volume of aluminum alloy scrap decreased from 2.85 million tons in 2010 to 1.92 million tons in 2016, and the import volume was less than 30% of the total scrap supply of 7.45 million tons

although the import of scrap is decreasing year by year, some situations are still ignored, that is, China has entered the peak period of scrap of aluminum since 2010. At present, the scrap is growing Zui fast, in which the scrap of forged aluminum alloy accounts for more than 60%, and the scrap of cast aluminum alloy accounts for 30%, with a total amount of more than 10million tons. Theoretically speaking, China no longer needs to import ordinary scrap aluminum alloy scrap as supplement at this stage, but the actual situation is that the production and operation modes of old and new scrap in China are not separated, and a large number of deformed aluminum alloy old scrap and new scrap are produced into ordinary cast aluminum alloy ingots as diluents of waste aluminum. This has contributed to the continuous expansion of the production capacity of cast aluminum alloys and the import of waste aluminum alloys. Obviously, if there is an advanced and standardized recycling system for deformed aluminum alloy waste, it is definitely not worthwhile to produce ordinary cast aluminum alloy by using the diluent of primary aluminum scrap and miscellaneous aluminum, which is an indisputable fact

aluminum will produce slag in the process of smelting, processing and recycling. In 2017, China's aluminum slag was conservatively estimated at more than 4.2 million tons, of which the content of metallic aluminum exceeded 2.2 million tons. If international advanced technology is adopted, 98% (2.156 million tons) of aluminum can be recycled, and 100% (2.044 million tons) of the remaining oxides can be converted into green industrial raw materials to realize resource recycling. At present, domestic technology is backward, and the recovery rate of aluminum is less than 55%. The harmless and resource-based treatment technology of oxide is still blank, that is to say, in 2017, only 1.21 million tons of aluminum was recovered from 4.2 million tons of aluminum slag in China, 990000 tons of aluminum became oxide, and the total amount of hazardous waste increased by 2.99 million tons from 2 million tons. According to the estimation of 15000 yuan per ton of aluminum, the direct loss of the whole industry is 15billion yuan. This is the second important fact that has long been ignored by Chinese aluminum industry enterprises

impact of trade war

in 2017, China imported about 820000 tons of aluminum waste from the United States, accounting for 50% of China's total aluminum waste imports and 52% of the total U.S. exports

obviously, the Sino US trade war does not pose a threat to the development of China's recycled aluminum industry. As long as China slightly improves the resource efficiency of aluminum by 2 percentage points, it is enough to replace the amount of imports from the United States. Therefore, the current prominent problem in China's aluminum industry is resource efficiency, and the core is technological innovation to improve competitiveness

challenges in improving resource efficiency

maximize the recycling of waste aluminum and aluminum containing waste for recycling

automatic mechanized pretreatment and classification technology, advanced crushing and separation technology, and make it widely available

advanced process control technology optimizes the treatment of elements and residues that are not suitable for reuse in recycled aluminum

expand the number of available aluminum alloys, adapt to the direct production of more aluminum alloy waste into products, and perform well in high quality and high added value

improve resource efficiency and realize graded recycling, such as using hot extrusion technology to separate waste materials that are polluted or mixed with casting alloys, that is, using the difference between the solidus temperature of forged and cast aluminum alloys for mechanical separation. Because the casting alloy has a high content of alloying elements, the solidus temperature is lower than that of the malleable alloy, so the mixture of forging and casting waste is heated to a temperature lower than the eutectic temperature, and then the forged alloy is separated by centrifugal force. X-ray fluorescence (XRF), laser-induced breakdown spectroscopy (LIBS), X-ray transmission (XRT) and other techniques are used to measure the concentration of alloy elements. Forged alloys with different compositions are melted after being separated by series

improve resource efficiency, optimize process technology, further reduce energy consumption and melting loss, reduce emissions, prolong furnace life, and improve alloy quality. For example, the residual elements Fe, Sn, Mn and Cu are eliminated by improving the melting technology. These elements are harmful to the mechanical properties, and some alloy elements need to be added to neutralize them. This requires more research to improve the knowledge of recycling technology. The manufacturing process of new alloys also needs to be optimized accordingly. The process basis needs to be studied to better understand the physical phenomena occurring in the melting, solidification and recycling processes, so as to create a knowledge base for aluminum producers to better control their processes. These aspects also include the following:

-- Methods for recycling aluminum waste from as many products as possible should be continued to be developed

-- the most cost-effective remelting process strategy should be adopted, including the technology of promoting the separation of unwanted elements such as Fe and Ni

-- alternative products, such as Al Fe deoxidizer, should be developed to take advantage of recycled aluminum parts that cannot be economically and effectively used to produce new aluminum alloys

-- new aluminum alloys designed for direct application in recycled aluminum should be seriously considered and studied

-- a study should be conducted to explore the potential to increase the number of alloys available for direct recovery, which should more accurately identify the source and expected composition range of current and future recycled metal content

improve resource efficiency and realize the harmlessness and resource utilization of slag. Aluminum slag and aluminum ash contain aluminum metal, salt and compound alumina, which can be completely recycled and recycled as non-toxic materials with advanced technology. At present, aluminum slag has been banned from landfilling in the United States, Canada and Europe. The treatment of aluminum slag has a considerable economic effect, which directly affects the profitability of enterprises. The measures that should be taken at present include the following:

-- optimize the operation process and prevent the oxidation of aluminum slag

-- shorten the transportation distance of aluminum slag, quickly seal and cool, and prevent oxidation loss

-- aluminum slag is treated under the protection of salt

-- establish a salt residue disposal system to stabilize the recovery rate of aluminum at more than 98%. Salt can be recycled indefinitely, and green inert alumina can enter the downstream industry

in short, there is considerable room to improve the resource efficiency of aluminum recycling in China. The focus of innovation is to improve the value of aluminum waste, reduce degradation and dilution, expand the ability to melt different types of waste, and establish and improve the slag treatment system. As long as these measures are in place, the recovered losses are immeasurable, which is of great importance to resource conservation

Copyright © 2011 JIN SHI