Recovery and utilization of aluminum

Investigation report on recycling of metal waste Significance of recycling of metal waste

Active recycling of scrap metal is an important way to realize the sustainable development of China's metal industry, which can not only solve the problem of insufficient raw materials in domestic metal mines to a certain extent, but also help to protect natural resources and reduce the impact and destruction on the ecological environment during metal production and consumption. For example, most non-ferrous metals, such as scrap steel, copper, aluminum, lead, zinc, gold and silver, have good recyclability, which promotes the repeated recycling of renewable metals without affecting their properties. This is an outstanding advantage of metal compared with polymer synthetic materials, wood and cement. Giving full play to this advantage can greatly alleviate the growing demand of social and economic development for mineral resources, obviously reduce the energy consumption of coal and electricity in the process of metal production, reduce environmental pollution, realize the sustainable development of metal industry and create a conservation-oriented society.

Take aluminum for example. First of all, it is generally believed that bauxite needs about two tons of alumina to produce one ton of primary aluminum, while bauxite needs about two tons to produce one ton of alumina. In other words, it takes at least four tons of bauxite resources to produce one ton of primary aluminum. At present, the annual output of primary aluminum in the world is about 25 million tons, and the annual consumption of bauxite exceeds 1 100 million tons. If this development continues, there will be less and less bauxite resources on the earth until one day it is exhausted. If the aluminum consumed by human beings can be recycled, as long as the recycling amount reaches half of the output, the consumption of bauxite will be reduced by about 50 million tons every year, which is of great significance to the protection of global bauxite resources. Secondly, compared with the production of one ton of primary aluminum ingots with bauxite raw materials, the production of one ton of alloy aluminum ingots with waste raw materials can save more than 95% of energy consumption. According to relevant statistics, each ton of raw aluminum ingot needs to consume 2 13.2TJ of energy (electric energy accounts for about 82%), while the energy consumption of producing one ton of recycled aluminum ingot is 5.5TJ (fuel accounts for about 80%), which is only 2.6% of the energy consumption of raw aluminum ingot production, and the comparative advantage is obvious. Because aluminum can be recycled repeatedly, the energy-saving effect is more obvious by using recycled aluminum waste to reproduce aluminum. In addition, compared with primary aluminum production, the amount and emission of carbon dioxide in secondary aluminum production are greatly reduced. According to statistics, the production of recycled aluminum can reduce carbon dioxide emissions by 9 1% compared with the production of primary aluminum by hydropower, by more than 97% compared with oil power generation, and by more than 97% compared with coal power generation, with remarkable environmental protection benefits.

From the perspective of sustainable development, the recycling of copper, lead, zinc and other metals is basically similar to that of aluminum, and there are also many energy savings in producing cathode copper and recovering zinc from waste copper and zinc. For example, the energy consumption of producing copper from waste copper is only19.7% of that of producing copper from mineral raw materials; The energy consumption of producing zinc from waste zinc is only 27.4% of that of mineral raw materials. The contribution rate of copper and zinc produced by scrap metal to resource protection and ecological environment is even higher than that of aluminum. Therefore, some experts predict that after the social savings of scrap metals reach a certain level, the metals needed by the market can no longer rely on mineral raw materials, and can be completely solved by recycling non-ferrous metals. Therefore, making full use of recycled raw materials is an inevitable way for China metal industry to achieve the goal of sustainable development.

Known environmental pollution, such as lead and artificial radiation, cannot be adapted by the self-purification ability of natural systems, so they accumulate in places harmful to the ecological circle and people. At the same time, the environmental pollution caused by metals such as mercury and the lack of such metal resources are also the result of our wishful thinking.

Metal waste recycling method;

Value of waste aluminum: after melting, it can be recycled for countless times to make recycled aluminum ingots, which can be used to manufacture mechanical industrial parts and civil products. The benefits to the environment and resources are that recycling aluminum can save 95% of the resources needed for new aluminum production.

Scrap iron is used to make iron salts and iron oxide red.

Scrap steel is used for steelmaking.

After copper scrap is smelted, it can be cast into parts of machinery industry. The recycling of metal waste will promote the sustainable development of circular economy and create an economical society. The recycling of renewable resources will benefit the country and the people.