| Currently, the waste electrical and electronic equipment (WEEE) is one of the fastest growing solid waste which our country produce about25million individuals amount to500,000ton according to the statistics by the Ministry of Environmental Protection and has grown at12～20%each year. WEEE contains not only enormous metals (gold, silver, copper, etc), plastic(propene polymer, acrylonitrile-butadiene-styrene, etc), glass and other materials, but also tremendous heavy metals(tin, lead, zinc, etc), flame retardants and other toxic and harmful substances, which causes potential environmental threats. With the rapid increase of the WEEE, millions of waste plastic were abandoned as it is widely used in household appliances which accounted for about30%(wt). WEEE plastic recycling could improve the utilization in its circulation compared to traditional approaches such as landfill, incineration, recycling of waste plastics has become the main direction of development. After consulting to the global technology of WEEE plastic shell recycling, this article mainly focused on the recycling of waste washing machine shell and investigated the technology in cleaning, sorting and modification (recycling).For the problems existing in recycling of waste plastic, long cleaning time, serious second ary pollution, this paper discussed a green cleaning method——ultrasonic cleaning technolo gy and studied the cleaning system using alkyl poly glycosidase (APG), alcohol ether sulpha te (AES), lauryl alcohol polyoxyethylene ether(AE) as surfactant. Its integrated effect is muc h better compared to commercial merchants and dosage less. Optimum conditions were as follows:45℃water containing1%homemade detergent cleaning8min by ultrasonic after soaking30min.Most companies only rely on the worker’ manual labour and experience which lead to bad classification, low added value of granulation products. For the production of high value products by waste plastics, it is the method to get single, high purity of waste plastics become the key technology. This essay studied the floatation principle of PP, ABS, PET and discussed the technology to separate waste plastics by flotation. Using a homemade plastic dissolved air flotation machine, with methyl isobutylcarbinol (MIBC) as frothing agent, tannic acid (TA), methyl cellulose (MC) and calcium lignosulfonate (CaLS) as wetting agent, exploring the affection of type of wetting agents, dosage of frother, time of adjustment in the whole system. Preliminary determined the optimal condition for the floating separation: using8mg/L TA to adjust15min, PP will rise after the floating5min from the mixed plastics, then use10mg/L MC or5mg/L CaLS as a wetting agent adjust15min, adding0.2ml/L MIBC for frother floating5min, the ABS and PET has separatedPolypropylene (PP) is one of the commonly used plastics in electronics, however, ageing, degradation, decreasing of notched impact strength and elongation could be the problems while using. It is difficult in recycling compared to PVT and PET. In this paper, studied the mechanical properties of PP modified by POE and SBS which both are commonly used as toughening agent in the waste washing machine shell, get the best project which would increase the impact strength by2.3times. The shock resistance of modified waste PP reached to the standard of washing machine, but needed to go further investigation on its tensile strength and flexural strength to meet the production requirements. |
PDF Full Text Request