Department of Environment and Equipment Engineering, Fujian University of Technology, Fuzhou 350108, People's Republic of China.
Waste Manag. 2013 May;33(5):1251-7. doi: 10.1016/j.wasman.2013.01.023. Epub 2013 Mar 7.
Waste printed circuit boards (PCBs) contain a large number of metals such as Cu, Sn, Pb, Cd, Cr, Zn, and Mn. In this work, an efficient and environmentally friendly process for metals recovery from waste PCBs by supercritical water (SCW) pre-treatment combined with acid leaching was developed. In the proposed process, waste PCBs were pre-treated by SCW, then the separated solid phase product with concentrated metals was subjected to an acid leaching process for metals recovery. The effect of SCW pre-treatment on the recovery of different metals from waste PCBs was investigated. Two methods of SCW pre-treatment were studied: supercritical water oxidation (SCWO) and supercritical water depolymerization (SCWD). Experimental results indicated that SCWO and SCWD pre-treatment had significant effect on the recovery of different metals. SCWO pre-treatment was highly efficient for enhancing the recovery of Cu and Pb, and the recovery efficiency increased significantly with increasing pre-treatment temperature. The recovery efficiency of Cu and Pb for SCWO pre-treatment at 420°C was 99.8% and 80%, respectively, whereas most of the Sn and Cr were immobilized in the residue. The recovery of all studied metals was enhanced by SCWD pre-treatment and increased along with pre-treatment temperature. Up to 90% of Sn, Zn, Cr, Cd, and Mn could be recovered for SCWD pre-treatment at 440°C.
废弃印刷电路板 (PCBs) 中含有大量金属，如 Cu、Sn、Pb、Cd、Cr、Zn 和 Mn。本工作提出了一种从废弃 PCB 中通过超临界水（SCW）预处理结合酸浸高效环保地回收金属的方法。在该工艺中，首先对废弃 PCB 进行 SCW 预处理，然后对浓缩金属的分离固相产物进行酸浸以回收金属。研究了 SCW 预处理对从废弃 PCB 中回收不同金属的影响。研究了两种 SCW 预处理方法：超临界水氧化（SCWO）和超临界水解聚（SCWD）。实验结果表明，SCWO 和 SCWD 预处理对不同金属的回收有显著影响。SCWO 预处理对提高 Cu 和 Pb 的回收率非常有效，随着预处理温度的升高，回收率显著提高。在 420°C 的 SCWO 预处理下，Cu 和 Pb 的回收率分别达到 99.8%和 80%，而大部分 Sn 和 Cr 则被固定在残渣中。SCWD 预处理可提高所有研究金属的回收率，且回收率随预处理温度的升高而增加。在 440°C 的 SCWD 预处理下，Sn、Zn、Cr、Cd 和 Mn 的回收率可达 90%。
