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E-waste treatment technology
 
Time: 2013-02-01 09:30:37     Author: Administrator

    According to “Regulations for the Administration of the Recovery and Disposal of Waste Electric and Electronic Products” (Decree of the State Council, No.551, came into effect on 1st Jan. 2011), the qualified enterprises usually deal with the five kinds of e-waste, including televisions, refrigerators, washing machines, air conditioners and computers. 

Waste Computer Monitor/Television

    At present, the CRT (cathode ray tube) display is the main category of scraped computers monitors/TVs in the domestic, of which the dismantling methods can be divided into two categories: i dismantling along the production line; ii dismantling at a single station. The process of these two methods are substantially the same except that the dismantling is completed by several workers in the former method and just by one worker in the latter one.

    The process of dismantling along the production line are mainly done manually and supplemented by machine. The general sequence includes: cutting off the power cord, removing the back cover after the removal of screws on it with pneumatic motor screw driver, cutting off the cables inside the computer monitor/TV, removing PCB (printed circuit board) and sending it to specific treatment process; removing the fixing screws of CRT, releasing vacuum of CRT by knocking off the neck glass manually, dismantling the deflection coil and speaker, sending CRT to specific treatment process. The significant feature of this method is that each worker just dismantle one component.

    Similarly, dismantling at a single station has the feature that each worker is responsible for the dismantling of the entire monitor/TV, but only a small part of scraped monitor/TVs are dismantled in this method at present.

    Most enterprises will make separation to the cone and screen glass of CRT before selling them to enterprises that have relevant treatment qualification, some enterprises will sell the CRT to treatment enterprises directly. 

Waste LCD Monitor

    There are just small amounts of LCD monitors be discarded, so the enterprises investigated don't have a specific treatment line for them and the main treatment method is dismantling manually. Some enterprises are carrying out small-scale treatment, such as Hua Xin Green Spring Environmental Co., LTD and TES-AMM (Suzhou) E-Waste Solution Co., LTD, but don't form industrial scale. The general dis sequence includes: cutting off the power cord, removing the plastic case after the removal of screws on it with screw driver, disassembling the components such as PCB, metal plate and fasteners and LCD panel and so on, the PCB will enter further treatment process. 

Waste Air Conditioner

     Similar to the dismantling of CRT and LCD monitor, the dismantling procedure of air conditioner also includes cutting off power cord, removing screws and cover. Disassembling the compressor, in which the refrigerant is recovered by refrigerant reclaiming machine. Compressor, heat exchanger and other components can be separated into plastic, copper, aluminum, iron and other categories of substances with further dismantling, treatment and separation. The process in some enterprises include manually dismantling, mechanical crushing, magnetic separation, winnowing and so on; some enterprises do these only by hand work, then the separated substances will be sold to recyclers. PCB will enter the enterprises’ specific treatment process if they have, or sold to PCB treatment enterprises with qualification. 

Waste Refrigerator

    Methods for waste refrigerators' treatment can be divided into two categories, what are briefly introduced below.

    Manual & mechanical method: dismantling scraped refrigerators manually to the level of separated components, including plastic, cable, glass, heat exchanger and PCB and so on; recovering the refrigerant, disassembling compressor and condenser from the main body; crushing the main body remain by machine, then separating the scraps by winnowing, magnetic separation, eddy current separation successively, and the resultant substances of each phase separation are plastics and polyurethane foam; iron; copper, aluminum and plastic.

    Mechanical method: putting scraped refrigerator on treatment line and removing the refrigerator door manually, recovering CFCs (chlorofluorocarbons) by specific equipment, the remain part will enter an enclosed integrated system including crushing, winnowing, magnetic separation, and eddy current separation equipment, and the final resultant substances are plastics, polyurethane foam, iron, copper and aluminum and son on.

Waste Washing Machine

    General process of waste washing machine treatment is cutting off power cord, inlet and outlet pipe, disassembling the panel, rotary switch, and the bottom counterweight successively. Then cutting the cable connecting washing machine outer case and inner cylinder, separating the washing machine iron shell; finally disassembling motor under the inner cylinder and large capacitor, pushing put the clutch of inner cylinder by hydraulic machine, making separation to the PP (polypropylene) plastic bucket and stainless steel inner cylinder tank.

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