溴
环氧树脂
超临界流体
苯酚
铜
降级(电信)
间歇式反应器
金属
材料科学
印刷电路板
化学
化学工程
核化学
冶金
有机化学
复合材料
催化作用
工程类
操作系统
电信
计算机科学
作者
Mingfei Xing,Fu-Shen Zhang
标识
DOI:10.1016/j.cej.2012.12.066
摘要
Waste printed circuit boards (WPCBs) contain high amount of brominated flame retardants and heavy metals which may bring a series of environmental and health problems. In the present study, an effective and benign process using sub- and supercritical water (sub/SCW) to simultaneously degrade brominated epoxy resin and recover metals from WPCBs was developed. Experiments were performed in a batch-type reactor with temperatures ranging from 200 to 400 °C, water adding amounts from 10 to 40 ml and holding times from 30 to 240 min. The results showed that brominated epoxy resins (BERs) could be quickly and efficiently decomposed under sub/SCW condition. The debromination rate was 97.8% by controlling the temperature, water adding amount and holding time at 400 °C, 40 ml and 120 min, respectively. Most of the bromine was changed into HBr and around 97.7% was enriched in water. Meanwhile, bromine-free oil was obtained of which the main compositions were phenol (58.5%) and 4-(1-methylethyl)-phenol (21.7%). After the sub/SCW treatments, the glass fibers and copper foils in the residue can be easily liberated and recovered respectively. The copper recovery rate reached 98.11% in the purities of 96.74% (grain size >2.0 mm) and 92.74% (0.147–2.0 mm). This study provides an efficient and green approach for WPCBs recycling.
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