Thermochemical treatment of non-metallic residues from waste printed circuit board: Pyrolysis vs. combustion
Thermochemical treatment of non-metallic residues from waste printed circuit board: Pyrolysis vs. combustion
复制标题
废印刷电路板非金属残留物的热化学处理：热解与燃烧
DOI：
10.1016/j.jclepro.2017.11.232
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发表时间：
2018
影响因子：
11.1
通讯作者：
Chen Mindong
中科院分区：
文献类型：
--
作者：
Shen Yafei;Chen Xingming;Ge Xinlei;Chen Mindong
废印刷电路板（NMF-WPCB）的非金属部分主要由具有高含量Br的塑料、玻璃纤维和金属（例如，Cu）。本文研究了碱、酸、碱盐预处理后的NMF-WPCB的热解和燃烧。铜（Cu，2.5%）、钙（Ca，28.7%）和铝（Al，6.9%）是主要的金属成分。同时，硅（Si，28.3%）和溴（Br，26.4%）是主要的非金属成分。重金属如Cu用酸显著减少92.4%（例如，HCl）预处理。塑料中的有机溴可以通过热解过程转化为HBr。碱预处理有利于Br在半焦中的固定。特别地，通过NaOH预处理结合热解过程，由于形成的HBr与NaOH反应生成NaBr，因此Br固定效率可高达53.6%。与热解过程相比，固相中的溴在燃烧过程中可以大部分转移到液相和气相中。气态有机溴会造成严重的环境污染。此外，生态风险评价分析表明，盐酸浸出与NaOH预处理相结合的方法具有很高的潜力，可用于NMF-WPCB的环境友好热解处置。
The non-metallic fraction of waste printed circuit board (NMF-WPCB) mainly consists of plastics with high content of Br, glass fibers and metals (e.g., Cu). This work studied the pyrolysis and combustion of NMF-WPCB pretreated by alkalis, acids and alkali-salts. Copper (Cu, 2.5%), calcium (Ca, 28.7%), and aluminum (Al, 6.9%) were the main metal constituents. Meanwhile, the silicon (Si, 28.3%) and the bromine (Br, 26.4%) were the predominant non-metallic constituents. The heavy metal such as Cu was significantly reduced by 92.4% with the acid (e.g., HCl) pretreatment. The organic Br in the plastics can be converted to HBr via the pyrolysis process. The alkali pretreatment was benefit for the Br fixation in the char. In particular, the Br fixation efficiency can reach up to 53.6% by the NaOH pretreatment combined with the pyrolysis process, since the formed HBr reacted with NaOH to generate NaBr. Compared with the pyrolysis process, most of Br in the solid phase can be transferred to the liquid and gas phase in the combustion process. The gaseous organic-Br can cause serious environmental pollution. Furthermore, the ecological risk assessment analysis showed that the HCl leaching combined with the NaOH pretreatment has a high potential to be used for the pyrolysis disposal of NMF-WPCB environmentally friendly.