A novel low-temperature alkaline smelting process is proposed to convert and separate amphoteric metals in crushed metal enrichment originated from waste printed circuit boards. The central composite design was used t...A novel low-temperature alkaline smelting process is proposed to convert and separate amphoteric metals in crushed metal enrichment originated from waste printed circuit boards. The central composite design was used to optimize the operating parameters,in which mass ratio of Na OH-to-CME, smelting temperature and smelting time were chosen as the variables, and the conversions of amphoteric metals tin, lead, aluminum and zinc were response parameters. Second-order polynomial models of high significance and3 D response surface plots were constructed to show the relationship between the responses and the variables. Optimum area of80%-85% Pb conversion and over 95% Sn conversion was obtained by the overlaid contours at mass ratio of Na OH-to-CME of4.5-5.0, smelting temperature of 653-723 K, smelting time of 90-120 min. The models were validated experimentally in the optimum area, and the results demonstrate that these models are reliable and accurate in predicting the smelting process.展开更多
Thermal decomposition of waste epoxy PCBs was performed in different atmospheres （nitrogen, argon, air and vacuum） at a heating rate of 10 ℃/rain by DSC-TGA, and the pyrolysis characteristic was analyzed. The gases...Thermal decomposition of waste epoxy PCBs was performed in different atmospheres （nitrogen, argon, air and vacuum） at a heating rate of 10 ℃/rain by DSC-TGA, and the pyrolysis characteristic was analyzed. The gases volatilized from the experiment were qualitatively analyzed by TG-FTIR. Kinetics study shows that pyrolysis reaction takes place between 300 and 400℃, and the activation energies are 256, 212 and 186.2 kJ/mol in nitrogen, argon and vacuum, respectively. There are two mass-loss processes in the decomposition under air atmosphere. In the first mass-loss process, the decomposition is the main reaction, and in the second process, the oxidation is the main reaction. The activation energy of the second mass-loss process is 99.6 kJ/mol by isothermal heat-treatments. TG-FTIR analysis shows carbon dioxide, carbon monoxide, hydrogen bromide, phenol and substituent phenol are given off during the pyrolysis of waste epoxy PCBs.展开更多
Pyrolysis kinetics of a kind of printed circuit board waste was investigated under various conditions with thermogravimetry (TG) in the present work. The dynamic thermogravimetric analysis curve and its derivative wer...Pyrolysis kinetics of a kind of printed circuit board waste was investigated under various conditions with thermogravimetry (TG) in the present work. The dynamic thermogravimetric analysis curve and its derivative were analyzed to obtain information on the kinetic parameters. The data from experiments were processed to determine the pyrolysis mechanism of printed circuit board and the kinetic parameters such as activation energy E(kJ/mol) and pre-exponential factor A(1/min). A tube-type apparatus was used to pyrolyze printed circuit board waste under different conditions,and the products were analysised by using FTIR and EPMA.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
Pyrolysis experiments of a typical printed circuit boards has been carried out under various conditions in a laboratory installation Liquid yield of 15%～21%, gas yield of 15%～20% and solid yield of about 60% were ob...Pyrolysis experiments of a typical printed circuit boards has been carried out under various conditions in a laboratory installation Liquid yield of 15%～21%, gas yield of 15%～20% and solid yield of about 60% were obtained The liquid products had high gross calorific values that might be recycled as fuel oils after simple treatment CO, CO 2 and N 2 were the main constitutes of the gas products Using combustion method, organic carbon of 7% in the solid products could be removed Then the solid products, which contained high purity fiberglass and CaCO 3, could be reused as filling materials in the process of SMC production In addition, the effects of final pyrolysis temperature (FPT) and particle size on pyrolysis products had been investigated The yield of gas products will be increased under high temperature and with powder展开更多
基金Projects(51074190,51234009)supported by the National Natural Science Foundation of ChinaProject(2014DFA90520)supported by International Cooperation Program of Ministry of Science of ChinaProject(20110162110049)supported by the Doctoral Scientific Fund Project of the Ministry of Education of China
文摘A novel low-temperature alkaline smelting process is proposed to convert and separate amphoteric metals in crushed metal enrichment originated from waste printed circuit boards. The central composite design was used to optimize the operating parameters,in which mass ratio of Na OH-to-CME, smelting temperature and smelting time were chosen as the variables, and the conversions of amphoteric metals tin, lead, aluminum and zinc were response parameters. Second-order polynomial models of high significance and3 D response surface plots were constructed to show the relationship between the responses and the variables. Optimum area of80%-85% Pb conversion and over 95% Sn conversion was obtained by the overlaid contours at mass ratio of Na OH-to-CME of4.5-5.0, smelting temperature of 653-723 K, smelting time of 90-120 min. The models were validated experimentally in the optimum area, and the results demonstrate that these models are reliable and accurate in predicting the smelting process.
基金Project(2006AA06Z375) supported by the National High-tech Research and Development Program of China
文摘Thermal decomposition of waste epoxy PCBs was performed in different atmospheres （nitrogen, argon, air and vacuum） at a heating rate of 10 ℃/rain by DSC-TGA, and the pyrolysis characteristic was analyzed. The gases volatilized from the experiment were qualitatively analyzed by TG-FTIR. Kinetics study shows that pyrolysis reaction takes place between 300 and 400℃, and the activation energies are 256, 212 and 186.2 kJ/mol in nitrogen, argon and vacuum, respectively. There are two mass-loss processes in the decomposition under air atmosphere. In the first mass-loss process, the decomposition is the main reaction, and in the second process, the oxidation is the main reaction. The activation energy of the second mass-loss process is 99.6 kJ/mol by isothermal heat-treatments. TG-FTIR analysis shows carbon dioxide, carbon monoxide, hydrogen bromide, phenol and substituent phenol are given off during the pyrolysis of waste epoxy PCBs.
文摘Pyrolysis kinetics of a kind of printed circuit board waste was investigated under various conditions with thermogravimetry (TG) in the present work. The dynamic thermogravimetric analysis curve and its derivative were analyzed to obtain information on the kinetic parameters. The data from experiments were processed to determine the pyrolysis mechanism of printed circuit board and the kinetic parameters such as activation energy E(kJ/mol) and pre-exponential factor A(1/min). A tube-type apparatus was used to pyrolyze printed circuit board waste under different conditions,and the products were analysised by using FTIR and EPMA.
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Pyrolysis experiments of a typical printed circuit boards has been carried out under various conditions in a laboratory installation Liquid yield of 15%～21%, gas yield of 15%～20% and solid yield of about 60% were obtained The liquid products had high gross calorific values that might be recycled as fuel oils after simple treatment CO, CO 2 and N 2 were the main constitutes of the gas products Using combustion method, organic carbon of 7% in the solid products could be removed Then the solid products, which contained high purity fiberglass and CaCO 3, could be reused as filling materials in the process of SMC production In addition, the effects of final pyrolysis temperature (FPT) and particle size on pyrolysis products had been investigated The yield of gas products will be increased under high temperature and with powder
