E-waste: refers to electrical or electronic equipment that is discarded and no longer in use, mainly including household appliances such as refrigerators, air-conditioners, washing machines, televisions and other household appliances, and computers and other communication electronics and other electronic technology obsolete products.
There are many types of e-waste, which can be roughly divided into two categories:
One category is the waste electronic products containing relatively simple materials and less harmful to the environment, such as refrigerators, washing machines, air-conditioning and other household appliances, as well as medical and scientific research electrical appliances, etc., which are relatively simple to dismantle and handle.
The other category is the materials contained in the more complex, more harmful to the environment of the waste electronic products, such as computers, television tubes within the lead, computer components containing arsenic, mercury and other harmful substances, cell phone raw materials of arsenic, cadmium, lead and a variety of other persistent degradation and bioaccumulation of toxic substances.
Expanded
E-waste treatment
1, chemical treatment
E-waste chemical treatment is also known as wet treatment, the crushed particles of e-waste into the acidic or alkaline liquid, the leachate and then through a series of processes, such as extraction, precipitation, replacement, ion exchange, filtration and The leachate is then extracted, precipitated, replaced, ion-exchanged, filtered and distilled in a series of processes to ultimately obtain high-grade metals. However, in the process of chemical treatment to use strong acids and highly toxic fluoride, etc., will produce a large number of waste liquids and emissions of toxic gases, a greater harm to the environment.
2, fire treatment
Fire treatment is the e-waste incineration, smelting, sintering, melting, etc., to remove plastics and other organic components to enrich the metal method. Pyro-processing can also cause serious harm to the environment. From the point of view of resource recovery, ecological and environmental protection, these methods are difficult to promote.
3, mechanical treatment
Electronic waste mechanical treatment is the use of physical property differences between the components of the sorting method, including disassembly, crushing, sorting and other steps, sorting and processing of materials and then after subsequent processing can be obtained respectively metal, plastic, glass and other renewable raw materials. This treatment method has the advantages of low cost, simple operation, not easy to cause secondary pollution, easy to realize the advantages of scale, is the hot spot of the development of countries.
4, microbial treatment
The use of microorganisms to extract gold and other precious metals is in the 1980s began to study the extraction of precious metals in the low content of materials in the new technology. The use of microbial activity makes gold and other precious metal alloys in other non-precious metals oxidized to become soluble and enter the solution, so that the precious metals exposed in order to facilitate the recovery. Biotechnology extraction of gold and other precious metals has the advantages of simple process, low cost, simple operation, but the leaching time is longer.
Baidu Encyclopedia-Electronic Waste