The most popular recycling problem of waste alumin

2022-07-30
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China has no special laws and regulations and no special promotion policies for the recycling of aluminum cans. However, due to the high value of aluminum, there are spontaneous collection groups of waste materials all over the country, who undertake the recycling of waste cans and resell them to recycling stations

it is estimated that the recovery rate of waste aluminum cans in China is about 85%, which is a country with a high recovery rate of waste cans in the world. At least 160000 tons of waste cans are recovered every year, and a small amount of imports, with a total amount of about 200000 tons. China is also a low-grade country in the world

although most cans can be recycled, this spontaneous situation can not form a scientific recycling system. The market is scattered and the recycling channels are unstable, which directly affects the utilization of waste aluminum cans. China's preferential tax policies for waste materials also need to be adjusted, otherwise it will affect the rational utilization of waste aluminum cans

technical problems

the recycling of waste cans began in the United States in the 1960s. The earliest is to directly melt the bulk cans into the furnace, but the burning loss is large; Then the waste cans are packed to improve the density, reduce the surface area, and improve the metal recovery rate. However, the product is still recycled aluminum ingot. After the 1980s, some countries in Europe and the United States began to use waste cans to produce alloy aluminum ingots of the original brand. The elements contained in the can body, cover and pull ring of the can are different. At present, there is no simple and economic method to separate the alloys of these three different components, and only the remelted aluminum ingot with more alloy components can be obtained by remelting

the most difficult problem in reuse is paint layer treatment. The main technical problem in producing 3004 aluminum alloy from waste cans is pretreatment. Developed countries have advanced pretreatment technology and equipment. They use a self ignition rotary kiln to carbonize the paint layer and remove the paint layer without pollution, simplifying the smelting process and improving the product quality

the main body of the recycling of cans in China is the scattered small melting workshop, which has the advantages of high efficiency, energy saving and high cost performance. There is no special pretreatment equipment and no paint stripping. Small crucible boilers are used for melting. The equipment is simple, the technology is backward and the working environment is poor, but the aluminum recovery rate is not low. The small crucible boiler also has its rationality. Generally, the smelting recovery rate can reach 85%~90%, which is not much different from that in developed countries, but it will cause the sensor damage to be obviously insufficient in large-scale application

unreasonable utilization of resources

the material of cans is a high-grade aluminum alloy. Due to backward technology, all waste cans have been degraded for use in China. So far, there is no enterprise producing the original aluminum alloy with waste cans. Developing waste cans to produce 3004 aluminum alloy will have high environmental, resource and economic benefits. It is the best way to use it to reduce the raw materials for producing can aluminum strip

most of the waste aluminum cans in China are used as additives in other production fields or as non-standard aluminum ingots, and few of them are really reduced for production. This is because the waste aluminum tank is still in an extensive stage in the process of recovery, storage and transportation, sorting, pretreatment and smelting processing, and the high-value waste aluminum resources are degraded for use. In particular, small enterprises generally adopt the mixing production mode, resulting in waste of resource utility and dislocation of resource allocation

at present, 2/3 of the cans in the United States are produced by melting with waste cans. Some foreign companies wanted to introduce this technology to China, but due to the scattered recycling of waste aluminum cans, low resource enrichment, lack of scale and imperfect tax system, scientific utilization is impossible

standards need to be changed

the main problem affecting the scientific utilization of waste aluminum cans in China is not technology, but insufficient quantity. If the conditions for large-scale utilization are not met, the technology required for industrial application will not appear, let alone environmental protection. So, can we solve this problem through import, which is bound to expand the foam granulator

waste aluminum cans belong to aluminum scrap and are allowed to be imported. However, the import inspection standard for non ferrous metal scrap generally stipulates that the amount of residual liquid of imported scrap shall not be high and shall be re welded; If the performance of components becomes worse than one in ten thousand, and the waste aluminum can has thin and light wall and is a special container for drinks, it is impossible for its residual liquid to meet this standard. Therefore, the import of waste aluminum cans has been hindered for a long time. Fortunately, the law enforcement environment is different across the country, and a small amount of imported scrap aluminum cans are available every year, but the scale effect is still not achieved

reprinted from: recycling and utilization of non-ferrous metals

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