The enrichment of copper from copper–cyanide wastewater by solvent extraction was investigated using a quaternary ammonium salt as an extractant. The influences of important parameters, e.g., organic-phase components...The enrichment of copper from copper–cyanide wastewater by solvent extraction was investigated using a quaternary ammonium salt as an extractant. The influences of important parameters, e.g., organic-phase components, aqueous pH values, temperature, inorganic anion impurities, CN/Cu molar ratio, and stripping reagents, were examined systematically, and the optimal conditions were determined. The results indicated that copper was effectively concentrated from low-concentration solutions using Aliquat 336 and that the extraction efficiency increased linearly with increasing temperature. The aqueous pH value and concentrations of inorganic anion impurities only weakly affected the extraction process when varied in appropriate ranges. The CN/Cu molar ratio affected the extraction efficiency by changing the distribution of copper–cyanide complexes. The difference in gold leaching efficiency between using raffinate and fresh water was negligible.展开更多
This paper presents an asymmetric anode structure and cathode extraction fast and soft recovery diode.The device anode is partial-heavily doped and partial-lightly doped.Theregion is introduced into the cathode.Firstl...This paper presents an asymmetric anode structure and cathode extraction fast and soft recovery diode.The device anode is partial-heavily doped and partial-lightly doped.Theregion is introduced into the cathode.Firstly,the characteristics of the diode are simulated and analyzed.Secondly,the diode was fabricated and its characteristics were tested.The experimental results are in good agreement with the simulation results.The results show that,compared with the P–i–N diode,although the forward conduction characteristic of the diode is declined,the reverse recovery peak current is reduced by 47%,the reverse recovery time is shortened by 20%and the softness factor is doubled.In addition,the breakdown voltage is increased by 10%.展开更多
The rapid development of the fluorinated pesticide industry has produced a large amount of fluorine-containing hazardous waste, especially inorganic fluoride-containing waste（IFCW）. A two-step process, including ext...The rapid development of the fluorinated pesticide industry has produced a large amount of fluorine-containing hazardous waste, especially inorganic fluoride-containing waste（IFCW）. A two-step process, including extraction and recovery, was developed to recover fluorine as synthetic cryolite from IFCW produced by the pesticide industry. The optimum conditions for extraction were found to be a temperature of 75℃, an initial p H（p Hi） of 12, a4-hr incubation time and a liquid-to-solid ratio of 40 m L/g; these conditions resulted in a fluorine extraction ratio of 99.0%. The effects of p H and the F/Al molar ratio on fluorine recovery and the compositional, mineralogical and morphological characteristics of the cryolite products were investigated. Field-emission scanning electron microscopy of recovered precipitates showed changes in morphology with the F/Al molar ratio. Coupling Fourier transform and infrared spectroscopy, X-ray diffraction indicated that the formation of Al F3-6was restricted as increasing p H. Both the amount of fluorine recovered and the quality of the cryolite were optimized at initial p H = 3 and a F/Al molar ratio 5.75. This study proposed a reliable and environmentally friendly method for the treatment of fluoridecontaining wastes, which could be suitable for industrial applications.展开更多
文摘The enrichment of copper from copper–cyanide wastewater by solvent extraction was investigated using a quaternary ammonium salt as an extractant. The influences of important parameters, e.g., organic-phase components, aqueous pH values, temperature, inorganic anion impurities, CN/Cu molar ratio, and stripping reagents, were examined systematically, and the optimal conditions were determined. The results indicated that copper was effectively concentrated from low-concentration solutions using Aliquat 336 and that the extraction efficiency increased linearly with increasing temperature. The aqueous pH value and concentrations of inorganic anion impurities only weakly affected the extraction process when varied in appropriate ranges. The CN/Cu molar ratio affected the extraction efficiency by changing the distribution of copper–cyanide complexes. The difference in gold leaching efficiency between using raffinate and fresh water was negligible.
基金Project supported by the National Natural Science Foundation of China(No.51177133)
文摘This paper presents an asymmetric anode structure and cathode extraction fast and soft recovery diode.The device anode is partial-heavily doped and partial-lightly doped.Theregion is introduced into the cathode.Firstly,the characteristics of the diode are simulated and analyzed.Secondly,the diode was fabricated and its characteristics were tested.The experimental results are in good agreement with the simulation results.The results show that,compared with the P–i–N diode,although the forward conduction characteristic of the diode is declined,the reverse recovery peak current is reduced by 47%,the reverse recovery time is shortened by 20%and the softness factor is doubled.In addition,the breakdown voltage is increased by 10%.
基金supported by the Hi-Tech Research and Development Program (863) of China (No. 2007AA061300)the Innovation Program of Undergraduate Students in Shanghai Province (No. 0400107092)Collaborative Innovation Center for Regional Environmental Quality
文摘The rapid development of the fluorinated pesticide industry has produced a large amount of fluorine-containing hazardous waste, especially inorganic fluoride-containing waste（IFCW）. A two-step process, including extraction and recovery, was developed to recover fluorine as synthetic cryolite from IFCW produced by the pesticide industry. The optimum conditions for extraction were found to be a temperature of 75℃, an initial p H（p Hi） of 12, a4-hr incubation time and a liquid-to-solid ratio of 40 m L/g; these conditions resulted in a fluorine extraction ratio of 99.0%. The effects of p H and the F/Al molar ratio on fluorine recovery and the compositional, mineralogical and morphological characteristics of the cryolite products were investigated. Field-emission scanning electron microscopy of recovered precipitates showed changes in morphology with the F/Al molar ratio. Coupling Fourier transform and infrared spectroscopy, X-ray diffraction indicated that the formation of Al F3-6was restricted as increasing p H. Both the amount of fluorine recovered and the quality of the cryolite were optimized at initial p H = 3 and a F/Al molar ratio 5.75. This study proposed a reliable and environmentally friendly method for the treatment of fluoridecontaining wastes, which could be suitable for industrial applications.
