Recycling of waste printed circuit boards: A review of current technologies and treatment status in China

Huang, Kui; Guo, Jie; Xu, Zhenming

doi:10.1016/j.jhazmat.2008.08.051

Cited by 512 publications

(290 citation statements)

References 30 publications

Supporting

Mentioning

260

Contrasting

Unclassified

Order By: Relevance

“…As the primary elements in most WEEE, printed circuit boards (PCBs) are widely used as the platform upon which microelectronic components such as semiconductor chips and capacitors are mounted. Waste PCBs contain approximately 70% nonmetals and 30% metals [2]. The nonmetal portions of waste PCBs consist of resins and brominated flame retardants (BFRs) [3].…”

Section: Introductionmentioning

confidence: 99%

Co-treatment of waste printed circuit boards and polyvinyl chloride by subcritical water oxidation: Removal of brominated flame retardants and recovery of Cu and Pb

Xiu

Zhang

2014

Chemical Engineering Journal

View full text Add to dashboard Cite

h i g h l i g h t sWe report an effective process for co-treatment of waste PCBs and PVC. Brominated flame retardants can be decomposed efficiently in co-treatment. Dechlorination of PVC was complete and safe. Cu and Pb in waste printed circuit boards can be recovered efficiently. Sn and Cr can be immobilized efficiently in the residue after co-treatment. t r a c tIn this work, an effective process for removal of brominated flame retardants (BFRs) and recovery of Cu and Pb from waste printed circuit boards (PCBs) was developed. In the process, waste PCBs and polyvinyl chloride (PVC) were co-treated by subcritical water oxidation (SBWO). PVC was used as a hydrochloric acid source and waste PCBs was used as a neutralizing reagent for the produced HCl. The dechlorination of PVC, removal of BFRs, and recovery of Cu and Pb could be achieved simultaneously by the one-step SBWO reaction. Experimental results showed that the dechlorination of PVC was complete when SBWO temperature exceeded 250°C. SBWO co-treatment was high efficient for the leaching of Cu and Pb from waste PCBs, and XRD spectra indicated that Sn was immobilized as SnO 2 in the residue after co-treatment. The optimum SBWO co-treatment conditions were temperature of 350°C, time of 60 min, solidliquid ratio of 1:9 g/ml, and PVC-to-PCBs ratio of 1:1, respectively. In the optimized co-treatment, 98.9% of Cu and 80% of Pb were recovered, while the leaching efficiencies of Sn and Cr were 15.3% and 3.9%, respectively. Meanwhile, approximately 100% of the bromine was changed into HBr and enriched in water after co-treatment.

show abstract

Section: Introductionmentioning

confidence: 99%

Co-treatment of waste printed circuit boards and polyvinyl chloride by subcritical water oxidation: Removal of brominated flame retardants and recovery of Cu and Pb

Xiu

Zhang

2014

Chemical Engineering Journal

View full text Add to dashboard Cite

show abstract

“…In general, waste PCBs contains approximately 30% metals and 70% nonmetals (Huang et al, 2009). The typical metals in PCBs consist of Cu, Sn, Pb, Cd, Cr, Zn, Ni, and Mn.…”

Section: Introductionmentioning

confidence: 99%

Recovery of metals from waste printed circuit boards by supercritical water pre-treatment combined with acid leaching process

2013

View full text Add to dashboard Cite

a b s t r a c tWaste 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.

show abstract

“…Technological innovation and intense marketing strategies engender a rapid turnover of electrical and electronic equipment (EEE) [1,2]. Since the mid-1990s, e-waste has been recognized as the fastest-growing component of the solid-waste stream in the industrialized world [3,4].…”

Section: Introductionmentioning

confidence: 99%

“…Printed circuit boards (PCBs), an essential part of almost all electric and electronic equipment, are widely subsistent in EEE [1]. In recent years, the average rate of worldwide PCBs manufacture increased by 8.7%, and this figure is much higher in Southeast Asia (10.8%) and mainland China (14.4%) [5].…”

Section: Introductionmentioning

confidence: 99%

“…Waste PCBs contain lots of valuable resources [6,7] together with plenty of hazardous materials [8,9], which are considered both an attractive secondary resource and an environmental contaminant [10]. Therefore, recycling of the Waste PCBs is an important subject not only from the treatment for waste but also from the recovery of valuable materials [1,11].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis of cuprous chloride and simultaneous recovery of Ag and Pd from waste printed circuit boards

Zhang

2013

Journal of Hazardous Materials

View full text Add to dashboard Cite

h i g h l i g h t s• An environmentally friendly process was developed for high quality cuprous chloride synthesis from waste PCBs.• Neither corrosive acid nor strong oxidant was used in the process.• Ag and Pd were simultaneously recovered during cuprous chloride synthesis.• A much faster reaction rate was achieved compared with other recovery methods.a r t i c l e i n f o t r a c tA benign and effective process for cuprous chloride synthesis and simultaneously recovery of Ag and Pd from waste printed circuit boards (PCBs) was developed in the present study. The main merit of the process is that neither corrosive acid nor strong oxidant was used. The PCBs were firstly pretreated by thermal shock process to obtain metallic particles (MPs), then cuprous chloride was synthesized by reacting MPs with cupric sulfate in the presence of sodium chloride. The optimum V Nacl /m CuSO 4 (mL/g) ratio, [Cu]/[Cu 2+ ] mole ratio, treatment time and operation temperature were 6, 0.95, 30 min and 60 • C, respectively. Approximately 98.5% of Cu could be recovered from the PCBs through two synthesis circles. During the synthesis process, Ag and Pd could be simultaneously recovered by forming a stable chloride complex since Cu 2+ played the role of oxidant in the system. The recovery percentages of Ag and Pd were 93.9% and 95.3%, respectively. Accordingly, it is believed that the process developed in the current study is benign and practical for copper and precious metal (Ag, Pd) recovery from waste PCBs.

show abstract

Recycling of waste printed circuit boards: A review of current technologies and treatment status in China

Cited by 512 publications

References 30 publications

Co-treatment of waste printed circuit boards and polyvinyl chloride by subcritical water oxidation: Removal of brominated flame retardants and recovery of Cu and Pb

Co-treatment of waste printed circuit boards and polyvinyl chloride by subcritical water oxidation: Removal of brominated flame retardants and recovery of Cu and Pb

Recovery of metals from waste printed circuit boards by supercritical water pre-treatment combined with acid leaching process

Synthesis of cuprous chloride and simultaneous recovery of Ag and Pd from waste printed circuit boards

Contact Info

Product

Resources

About