废弃印刷线路板共热解影响因素及热解产物表征

热解是资源化利用废弃印刷线路板的重要方法之一。分别以沸石和Fe₃O₄为共热解剂,探讨了共热解剂与废弃线路板的质量比以及热解温度对液相产物产率的影响,并对热解后固、液、气三相产物进行了表征。结果表明,共热解剂的添加不会影响热解油的产率,但可有效降低液相中溴化有机物的含量。热解液相产物组分分析结果表明,直接热解废弃线路板时会有大量溴化有机物释放到液相产物中。加入共热解剂后,苯酚及其同系物成为液相产物的主要成分,溴变成主要以无机溴化物的形式存在。同时,不同共热解剂对废弃线路板的热解影响也不同。Fe₃O₄共热解时,液相产物中小分子苯类物质更多,这可能是由于铁类物质对大分子有机物的分解作用更强。共热解剂在高温下比较稳定,热解后固体主要含有共热解剂、玻璃纤维以及重金属,而热解气的主要成分则为H₂、CH₄和CO₂。

Factors that affects co-pyrolysis of waste printed circuit board and characterization of pyrolysis products

Pyrolysis was one of the methods employed for waste printed circuit board (WPCB) recycle. In this research, WPCB was co-pyrolyzed with zeolite and Fe₃O₄, the effects of mass ratio and temperature on liquid yield was investigated. In addition, solid, liquid and gaseous products from pyrolysis were characterized in details. Results showed that the addition of co-pyrolysis reagent did not affect liquid yield. The release of Br-containing organics into liquid was effectively suppressed. Analysis of liquid compositions revealed that Br-containing organics were found in liquid when WPCB was pyrolyzed alone. With the addition of co-pyrolysis reagent, phenol and its homologues predominated. Inorganic Br became the major form of Br compounds. The effects of co-pyrolysis reagent varied. The addition of Fe₃O₄ led to the generation of more small-molecule benzene products. This could be attributed to the fact that iron oxides were effective in breaking up macro-molecule organics in WPCB. Co-pyrolysis reagents were stable under high temperature. And the resultant solid products from pyrolysis were mainly composed of these reagents together with glass fiber and heavy metals from WPCB. On the other hand, pyrolysis gases were mainly composed of H₂, CH₄ and CO₂.