液氮改性-机械破碎法分离回收废旧光伏电池板

随着我国光伏装机总量逐年攀升,未来将会有大量的光伏固废需要回收处理。光伏电池板作为光伏发电设备的主要部件,对其进行简单的破碎热解回收,释放的有毒气体对生态环境有极大危害,并且其中的有价资源也无法高值利用。采用液氮对光伏电池板进行改性,并利用机械破碎法破碎改性后的光伏电池板。研究了液氮改性对电池板硅材料富集和玻璃去除的影响,考察了液氮改性—机械破碎后电池板中各主要材料如硅材料、玻璃、金属和有机物在不同粒级破碎颗粒中的分布情况。结果表明,与未改性光伏电池板相比,液氮改性后的光伏电池板EVA(乙烯—醋酸乙烯共聚物)胶膜粘黏力显著下降、脆性升高,更易于从各组分的界面处脱落,玻璃去除率和硅富集程度明显高于常规破碎的。在破碎8s时,硅富集程度最大,富集率为72%,玻璃去除率为70%。通过机械分级破碎预处理,可促使光伏电池板表面大部分EVA胶膜暴露,在有效减少后处理物料质量的同时,创造更多的扩散通道,可强化后续化学法的深度分离。

Liquid nitrogen modification-mechanical crushing method to separate and recycle waste photovoltaic panels

As the total installed photovoltaic capacity in my country is increasing year by year, there will be a large amount of photovoltaic solid waste that needs to be recycled and processed in the future. Photovoltaic panel is the main component of photovoltaic power generation equipment. The toxic gas released by simple crushing and pyrolysis of photovoltaic panels has great harm to the ecological environment. Moreover, the valuable resources can not be used with high value. Liquid nitrogen was used to modify the photovoltaic panels, and the mechanical crushing method was used to crush the modified photovoltaic panels. In this paper, the effects of liquid nitrogen modification on silicon material enrichment and glass removal were studied, and the distribution of main materials such as silicon material, glass, metal and organic matter in different particle size fractions was investigated. The results show that compared with unmodified PV panels, the adhesion of EVA (Ethylene Vinyl Acetate Copolymer) in PV panels decreases and the brittleness of EVA increases after liquid nitrogen treatment, and it is easier to fall off from the interface of each component. The removal rate and enrichment rate of glass modified by liquid nitrogen are better than that of normal temperature. When the PV panels were mechanically broken for 8 s after liquid nitrogen modification, the highest silicon enrichment rate was 72%, and the glass removal rate was 70%. As a pre-treatment step of photovoltaic panels, mechanical crushing makes most EVA film on the surface of photovoltaic panels exposed. At the same time, the weight of the post-treatment material is effectively reduced, and the diffusion channel is more created, which can strengthen the deep separation of subsequent chemical methods.