The recycling of waste printed circuit board(WPCBs) is of great significance for saving resources and protecting the environment. In this study, the WPCBs were pyrolyzed by microwave and the contained valuable metals ...The recycling of waste printed circuit board(WPCBs) is of great significance for saving resources and protecting the environment. In this study, the WPCBs were pyrolyzed by microwave and the contained valuable metals Cu, Sn and Pb were recovered from the pyrolyzed WPCBs. The effect of pyrolysis temperature and time on the recovery efficiency of valuable metals was investigated. Additionally, the characterization for morphology and surface elemental distribution of pyrolysis residues was carried out to investigate the pyrolysis mechanism. The plastic fiber boards turned into black carbides, and they can be easily separated from the metals by manual. The results indicate that 91.2%, 96.1% and 94.4% of Cu, Sn and Pb can be recovered after microwave pyrolysis at 700 °C for 60 minutes. After pyrolysis, about 79.8%(mass)solid products, 11.9%(mass) oil and 8.3%(mass) gas were produced. These gas and oil can be used as fuel and raw materials of organic chemicals, respectively. This process provides an efficient and energy-saving technology for recovering valuable metals from WPCBs.展开更多
采用电动力学技术,研究废旧印刷线路板(WPCBs)投加量、离子液体体积分数、电流密度、电动力学时间以及H_2O_2用量等对Cu回收率的影响以及电动力学过程中铜的分布特性。研究结果表明:Cu基本集中于阴极区,并以粉末的形式回收;各因素对Cu...采用电动力学技术,研究废旧印刷线路板(WPCBs)投加量、离子液体体积分数、电流密度、电动力学时间以及H_2O_2用量等对Cu回收率的影响以及电动力学过程中铜的分布特性。研究结果表明:Cu基本集中于阴极区,并以粉末的形式回收;各因素对Cu回收率均有不同程度的影响,其中电动力学时间的影响最为显著;电流密度过高会导致电流效率的下降而降低Cu的回收率;加入2 g WPCBs,当离子液体体积分数为10%,电流密度为20 m A/cm^2,H_2O_2体积为2 m L时,处理24 h,Cu的总回收率为84.6%;所得金属粉末主要以Cu和Cu_2O的形式存在,含量为97.86%。此法可以直接在组成极其复杂的WPCBs中回收金属铜,为其资源化提供了新的途径。展开更多
Copper recovery is the core of waste printed circuit boards （WPCBs） treatment. In this study, we proposed a feasible and efficient way to recover copper from WPCBs concentrated metal scraps by direct electrolysis an...Copper recovery is the core of waste printed circuit boards （WPCBs） treatment. In this study, we proposed a feasible and efficient way to recover copper from WPCBs concentrated metal scraps by direct electrolysis and thctors that affect copper recovery rate and purity, mainly CuSO4.5H2O concentration, NaCI concentration, H2SO4 concentration and current density, were discussed in detail. The results indicated that copper recovery rate increased first with the increase ofCuSO4- 5H2O, NaCI, H2SO4 and current density and then decreased with further increasing these conditions. NaCI, H2SO4 and current density also showed a similar impact on copper purity, which also increased first and then decreased. Copper purity increased with the increase of CuSO4.5H2O. When the concentration of CuSO4-5H2O NaCI and H2oSO4 was respectively 90, 40 and 118 g/L and current density was 80 mA/cm-, copper recovery rate and purity was up to 97.32% and 99.86%, respectively. Thus, electrolysis proposes a feasible and prospective approach for waste printed circuit boards recycle, even for e-waste, though more researches are needed for industrial application.展开更多
基金supported by the National Key Research and Development Program of China (2019YFC1908404)the National Natural Science Foundation of China (Nos. 51834008, 51874040,52034002)+1 种基金the Guangxi Innovation-Driven Development Project(AA18242042-1)the Fundamental Research Funds for the Central Universities (FRF-TP-18-020A3)。
文摘The recycling of waste printed circuit board(WPCBs) is of great significance for saving resources and protecting the environment. In this study, the WPCBs were pyrolyzed by microwave and the contained valuable metals Cu, Sn and Pb were recovered from the pyrolyzed WPCBs. The effect of pyrolysis temperature and time on the recovery efficiency of valuable metals was investigated. Additionally, the characterization for morphology and surface elemental distribution of pyrolysis residues was carried out to investigate the pyrolysis mechanism. The plastic fiber boards turned into black carbides, and they can be easily separated from the metals by manual. The results indicate that 91.2%, 96.1% and 94.4% of Cu, Sn and Pb can be recovered after microwave pyrolysis at 700 °C for 60 minutes. After pyrolysis, about 79.8%(mass)solid products, 11.9%(mass) oil and 8.3%(mass) gas were produced. These gas and oil can be used as fuel and raw materials of organic chemicals, respectively. This process provides an efficient and energy-saving technology for recovering valuable metals from WPCBs.
文摘采用电动力学技术,研究废旧印刷线路板(WPCBs)投加量、离子液体体积分数、电流密度、电动力学时间以及H_2O_2用量等对Cu回收率的影响以及电动力学过程中铜的分布特性。研究结果表明:Cu基本集中于阴极区,并以粉末的形式回收;各因素对Cu回收率均有不同程度的影响,其中电动力学时间的影响最为显著;电流密度过高会导致电流效率的下降而降低Cu的回收率;加入2 g WPCBs,当离子液体体积分数为10%,电流密度为20 m A/cm^2,H_2O_2体积为2 m L时,处理24 h,Cu的总回收率为84.6%;所得金属粉末主要以Cu和Cu_2O的形式存在,含量为97.86%。此法可以直接在组成极其复杂的WPCBs中回收金属铜,为其资源化提供了新的途径。
文摘Copper recovery is the core of waste printed circuit boards （WPCBs） treatment. In this study, we proposed a feasible and efficient way to recover copper from WPCBs concentrated metal scraps by direct electrolysis and thctors that affect copper recovery rate and purity, mainly CuSO4.5H2O concentration, NaCI concentration, H2SO4 concentration and current density, were discussed in detail. The results indicated that copper recovery rate increased first with the increase ofCuSO4- 5H2O, NaCI, H2SO4 and current density and then decreased with further increasing these conditions. NaCI, H2SO4 and current density also showed a similar impact on copper purity, which also increased first and then decreased. Copper purity increased with the increase of CuSO4.5H2O. When the concentration of CuSO4-5H2O NaCI and H2oSO4 was respectively 90, 40 and 118 g/L and current density was 80 mA/cm-, copper recovery rate and purity was up to 97.32% and 99.86%, respectively. Thus, electrolysis proposes a feasible and prospective approach for waste printed circuit boards recycle, even for e-waste, though more researches are needed for industrial application.
