关键词:

酚醛型线路板, 回收, 碳酸钙, 热重分析, 混合热解, 脱溴

Abstract:

Phenolic resin type waste PCB (wPCB) is one of the most important kinds of waste electrical and electronic equipment (WEEE) in China.It is usually hard to recycle for its high content of brominated flame retardants, so the key of recycling the wPCB is to debrominate, i.e., to convert the organic bromides into inorganic ones, e.g., hydrogen bromide (HBr).Hence, pyrolytic debromination experiments were conducted to reveal the effect of blending calcium carbonate (CaCO₃) with the wPCB in pyrolysis.The results of thermogravimetric analysis indicated that CaCO₃ could absorb HBr to restrain them from reacting with organic molecules when the wPCB was blended with CaCO₃ powders in pyrolysis.Further, a pyrolysis experiment blending the wPCB with CaCO₃ in a quartz glass tube reactor was performed by means of silver nitrate titration to determine the content of inorganic bromides.The results showed that 93.4% inorganic bromides were trapped when the wPCB and CaCO₃ blended in the same quantity, and two times of inorganic bromides than without blending CaCO₃ were produced.Moreover, when the wPCB was pyrolyzed with CaCO₃, the contents of organic bromides in the pyrolysates, measured by GC/MS, were 25% less than those when just wPCB was pyrolyzed.It proved that the CaCO₃ helped to debrominate in the pyrolysis of the wPCB.

Key words:

酚醛型线路板, 回收, 碳酸钙, 热重分析, 混合热解, 脱溴