Because recycled aluminum will produce a lot of scum in the production process, it is generally called aluminum ash. The content of metallic aluminum in aluminum ash is high, so general enterprises use the method of frying ash in a large pot to recover aluminum, and a large amount of smoke and dust will be produced during the whole process of frying ash. There are also some small and medium-sized enterprises that think coal is cheap and still burn coal directly at present. If coal can't burn completely, the flue gas will contain a lot of carbon monoxide gas, which will produce a lot of smoke and dust. Direct coal burning is also the main source of environmental pollution in the secondary aluminum industry. In order to obtain high-quality aluminum alloy, some enterprises usually add various solvents and refining agents in the smelting process. After melting, solid solvents and refining agents will react with impurities in the melt, producing scum and smoke. If the additives are not selected properly, toxic and harmful gases may be produced.
According to the survey, in addition to regular secondary aluminum enterprises, many enterprises have no environmental protection equipment, and some have simple environmental protection equipment, but they exist in name only. In particular, some smaller enterprises simply do not have the ability to build environmental protection equipment. "Every household smelt aluminum, and every household smoked" is a true portrayal of some small aluminum smelting enterprises concentrated areas. In recent years, the relevant departments have stepped up efforts to improve the environment, but after the improvement, some secondary aluminum enterprises have adopted the way of "stopping production during the day and producing at night" to cover up the pollution problem.
The most important reason for the backwardness of environmental protection in secondary aluminum industry is the environmental awareness of enterprise decision makers: some do not know that secondary aluminum production is polluted; Some people refuse to invest in environmental protection. In fact, most enterprises (with an annual output of more than 5,000 tons) have the ability to invest in environmental protection facilities, while decision makers are unwilling to invest in environmental protection. Although some enterprises have built environmental protection equipment, they are just putting on a show. They usually don't turn on the computer, and only deal with it when the environmental protection department checks it.
However, it is gratifying that many secondary aluminum enterprises have established gas generators to convert solid fuel into gas fuel, which not only greatly reduces the pollution caused by coal burning, but also reduces the production cost due to the improvement of combustion efficiency, which is undoubtedly a scientific choice.
Some enterprises no longer use additives that have an impact on the environment. At the same time, in order to avoid the pollution caused by recovering aluminum from aluminum ash, rotary kiln is used to treat aluminum ash, or press is used to recover aluminum from aluminum ash, so as to minimize the pollution caused by treating aluminum ash.
At present, China's secondary aluminum enterprises are "small, numerous and scattered" with low concentration; The dismantling and smelting conditions of waste metals are poor, which pollutes the environment; Due to the complexity of scrap metal resources, the commodity inspection and pricing of import links are more complicated, and the reduction of VAT deduction of production and processing enterprises increases tax revenue, which is not conducive to industrial upgrading and development. Faced with these problems, it is necessary to actively take corresponding countermeasures. The suggestions are as follows: with the increasing import volume, it is more appropriate to implement specific tax with low tax rate in the import link, which is convenient to reduce the complexity of commodity inspection and pricing, reduce the customs clearance cost of enterprises, and is conducive to the import of renewable resources; At the same time, standardize the laws and policies of recycled metal production parks, guide dismantling and processing enterprises to use environmental protection facilities, solve the environmental pollution caused by "small, large and scattered", gradually improve the level of technology and equipment, and realize large-scale production; Increase investment in science and technology and improve metal recovery rate; Increase the proportion of value-added tax deduction for recycling metal processing and utilization enterprises, reduce tax revenue, and promote enterprise upgrading and development of large-scale production. For details, please refer to Nonferrous Business Alliance.