The main methods of treatment and disposal of waste e-waste are chemical treatment, fire, mechanical treatment, electrochemical method or a combination of several methods. Specifically as follows:
1, chemical treatment
Chemical treatment of e-waste, also known as wet processing, will be 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 distillation and ultimately get high-grade metal.
2, 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 leach gold and other precious metals in the 1980s began to study the extraction of low content of precious metals in the material of the new technology. h.brandl et al. the use of thiobacillus oxydans after crushing pre-treatment of e-waste crushed leaching test, in the selected temperature, ph, the amount of input, can be more than 90% of the leached cu, zn and ni, and pb was stabilized in the precipitate as pbso4.
Extended information:
Harms of e-waste
E-waste has a complex composition, with more than half of the materials harmful to the human body, and some of them are even highly toxic. For example, a computer has more than 700 components, half of which contain mercury, arsenic, chromium and other various toxic chemicals; televisions, refrigerators, cell phones and other electronic products also contain lead, chromium, mercury and other heavy metals; laser printers and photocopiers contain toner and so on.
When e-waste is landfilled or incinerated, the heavy metals in it penetrate into the soil and enter rivers and groundwater, which will cause pollution of local soil and groundwater, and directly or indirectly cause damages to the local residents and other organisms; and the organic matter is incinerated, which releases a large amount of hazardous gases, such as highly poisonous dioxins, furans, PCBs and other carcinogens, which cause harm to the natural environment and human body. cause harm to the natural environment and human body.
Baidu Encyclopedia-Electronic Waste