Pretreatment of high content of Si- and Al-containing cyanide tailings by water leaching to remove some impurities, such as the major impurities minerals of Si and A1, as well as its effect on Fe extraction in the wat...Pretreatment of high content of Si- and Al-containing cyanide tailings by water leaching to remove some impurities, such as the major impurities minerals of Si and A1, as well as its effect on Fe extraction in the water leaching process was investigated. The effects of different parameters on iron recovery were studied, and the reaction parameters were proposed as follows： sodium carbonate content of 30%, water leaching at 60 ~C for 5 min, liquid/solid ratio of 15：1, and exciting current of 2 A. Under these optimal conditions, magnetic concentrate containing 59.11% total iron and a total iron recovery rate of 76.12% was obtained. In addition, the microstructure and phase transformation of the process of water leaching were studied by X-ray powder diffraction technique （XRD）, Electronic image of backscattering （BEI）, X-ray fluorescence （XRF）, and energy dispersive spectrometry （EDS）. The results indicate that the soluble compound impurities generated in the roasting process are washed out, and the dissoluble substances enter into nonmagnetic materials by water leaching, realizing the effective separation of impurities and Fe.展开更多
Embedding direct reduction followed by magnetic separation was conducted to fully recover iron and titanium separately from beach titanomagnetite （TTM）. The influences of reduction conditions, such as molar ratio of...Embedding direct reduction followed by magnetic separation was conducted to fully recover iron and titanium separately from beach titanomagnetite （TTM）. The influences of reduction conditions, such as molar ratio of C to Fe, reduction time, and reduction temperature, were studied. The results showed that the TTM concentrate was reduced to iron and iron-titanium oxides, depending on the reduction time, and the reduction sequence at 1 200℃ was suggested as follows ： Fe2.75 Ti0.25O4→Fe2TiO4→FeTiO3→FeTi2O5. The reduction temperature played a considerable role in the reduction of TTM concentrates. Increasing temperature from 1 100 to 1 200℃ was beneficial to recovering titanium and iron, whereas the results deteriorated as temperature increased further. The results of X-ray diffraction and scanning electron microscopy analyses showed that low temperature （≤1100℃） was unfavorable for the gasification of reductant, resulting in insufficient reducing atmosphere in the reduction process. The molten phase was formed at high temperatures of 1250-1 300℃, which accelerated the migration rate of metallic particles and suppressed the diffusion of reduction gas, resulting in poor reduction. The optimum conditions for reducing TTM concentrate are as follows： molar ratio of C to Fe of 1.68, reduction time of 150 min, and reduction temperature of 1 200℃. Under these conditions, direct reduction iron powder, assaying 90.28 mass% TFe and 1.73 mass% TiO2 with iron recovery of 90.85%, and titanium concentrate, assaying 46.24 mass% TiO2 with TiO2 recovery of 91.15%, were obtained.展开更多
Magnetic plant biomonitoring has been proven to be an effective tool in the assessment of air quality. Kuwait presents a unique environment due to its dry desert climatic conditions and prevailing dry deposition patte...Magnetic plant biomonitoring has been proven to be an effective tool in the assessment of air quality. Kuwait presents a unique environment due to its dry desert climatic conditions and prevailing dry deposition patterns that may affect accumulation rates of magnetic mineral particles. This study evaluated two widely distributed ornamental species, buttonwood (Conocarpus erectus) and palm (Phoenix dactylifera) for their effectiveness as biomagnetic monitors over three different land use classes (urban, suburban and industrial land classes). The differences between land use classes were classified by their proximity to major pollution sources as well as population density. Leaf sampling was conducted over various heights and distances from the nearest road. Total leaf saturated isothermal magnetization (SIRM), hard isothermal magnetization (HIRM), hard isothermal magnetization percentage (HIRM%) and s-ratio have been measured. Scanning electron microscopy (SEM) was used to analyze leaf surface micromorphology. It was determined that NRM values are similar for all land use classes and species, ranging from 0.3 to 0.5 μA. Palm leaf overall magnetic concentration was identified to be higher at the industrial land use class than at the urban land use class, indicating high coercivity minerals to magnetically dominate the land use classes. Additionally, total leaf SIRM was determined to be higher at short distances of 0 - 5 meters from the vicinity of the road. The surface rugosity of palm has deep ridges and furrows with ununiform wax projections across the leaf surface, while buttonwood has a smooth wax film with low relief. Differences in leaf micromorphology in addition to plant physiology, justify species magnetic parametric variances. Palm leaf had an average SIRM value that is 120% higher than buttonwood. It has been highlighted that through the application of the magnetic parameter results to spatial distribution maps that there is an association between particulate matter (PM) and the locality of main roads and local services that may experience higher intensities of traffic.展开更多
A cantilever-structured magneto-mechano-electric(MME)generator comprising a magnetoelectric composite with a magnet proof mass is a potential candidate for powering autonomous wireless sensor networks.Recently,the con...A cantilever-structured magneto-mechano-electric(MME)generator comprising a magnetoelectric composite with a magnet proof mass is a potential candidate for powering autonomous wireless sensor networks.Recently,the concept of a magnetic flux concentrator(MFC)to enhance the output performance of the MME generator by focusing the ultralow-intensity magnetic field into the MME generator was introduced.However,the MFC-concentrated magnetic flux mostly focused on the end tip of the MME cantilever rather than at the magnet proof mass located on the cantilever beam.Considering that the torque generated by the magnet proof mass contributes more than half of the output power of an MME generator,optimizing the volume and position of the proof-mass with MFC is crucial for better performance.Furthermore,a smaller proof-mass is desirable for the long-term reliability of cantilevertype harvesters.Hence,we investigated the effect of the position and weight(volume)of the magnet proof mass with respect to the MFC on the output performance of the MME generator through finite element analysis and experiments.The MME generator with the lighter magnet proof mass at the optimized position generated a maximum power of 5.35 mW under a 10 Oe magnetic field,which was 210%of that of the MME configuration used in our previous study.Furthermore,the MME generator showed broadband characteristics around the practical frequency of 60 Hz,which could provide more freedom to design the harvester with high performance.展开更多
A passive current sensor,consisting of SmFe_(2)/PZT/SmFe_(2)self-biased magnetoelectric(ME)composite and Fe_(73.5)Cu_(1)Nb_(3)Si_(13.5)B_(9)nanocrystalline flux concentrator for weak current detection at power-line fr...A passive current sensor,consisting of SmFe_(2)/PZT/SmFe_(2)self-biased magnetoelectric(ME)composite and Fe_(73.5)Cu_(1)Nb_(3)Si_(13.5)B_(9)nanocrystalline flux concentrator for weak current detection at power-line frequency,was fabricated and characterized.Giant magnetostrictive material of SmFe_(2)plate with large anisotropic constant provides a huge internal anisotropic field to bias the ME transducer in closed magnetic loop.Consequently,the additional magnetomotive force induced by the internal field and the corresponding increased effective permeabil-ity contribute to the improvement of the sensitivity.Experimental results demonstrate that the presented sensor has a higher sensitivity of 152 mV·A^(-1)at 50 Hz with a slight nonlinearity of~0.01%full scale(FS)and matches well with the predicted value.This presented current-sensing device exhibits approximately 2.3 times higher sensitivity than that of conventional ME composite with[Pb(Zr_(0.48),Ti_(0.52)O_(3)](PZT)and Terfenol-D plates serving as a key sensitive component.In addition,time stabilities of the presented sensor were evaluated for a long period of 72 h and analyzed through mathematical statistics method,and favorable stabilities with an uncertainty of 0.5μV are obtained in continuous 1 h testing.These results provide a significant advancement toward promising application of the tri-layer self-biased ME laminate for power-line elec-tric cords monitoring.展开更多
基金Projects(ZR2010EL006,Y2007F60) supported by the National Science Foundation of Shandong Province of ChinaProject(J12LA04) supported by High Education Science Technology Program of Shandong Province,China
文摘Pretreatment of high content of Si- and Al-containing cyanide tailings by water leaching to remove some impurities, such as the major impurities minerals of Si and A1, as well as its effect on Fe extraction in the water leaching process was investigated. The effects of different parameters on iron recovery were studied, and the reaction parameters were proposed as follows： sodium carbonate content of 30%, water leaching at 60 ~C for 5 min, liquid/solid ratio of 15：1, and exciting current of 2 A. Under these optimal conditions, magnetic concentrate containing 59.11% total iron and a total iron recovery rate of 76.12% was obtained. In addition, the microstructure and phase transformation of the process of water leaching were studied by X-ray powder diffraction technique （XRD）, Electronic image of backscattering （BEI）, X-ray fluorescence （XRF）, and energy dispersive spectrometry （EDS）. The results indicate that the soluble compound impurities generated in the roasting process are washed out, and the dissoluble substances enter into nonmagnetic materials by water leaching, realizing the effective separation of impurities and Fe.
基金financially supported by the National Natural Science Foundation of China (Grant No.51474018)
文摘Embedding direct reduction followed by magnetic separation was conducted to fully recover iron and titanium separately from beach titanomagnetite （TTM）. The influences of reduction conditions, such as molar ratio of C to Fe, reduction time, and reduction temperature, were studied. The results showed that the TTM concentrate was reduced to iron and iron-titanium oxides, depending on the reduction time, and the reduction sequence at 1 200℃ was suggested as follows ： Fe2.75 Ti0.25O4→Fe2TiO4→FeTiO3→FeTi2O5. The reduction temperature played a considerable role in the reduction of TTM concentrates. Increasing temperature from 1 100 to 1 200℃ was beneficial to recovering titanium and iron, whereas the results deteriorated as temperature increased further. The results of X-ray diffraction and scanning electron microscopy analyses showed that low temperature （≤1100℃） was unfavorable for the gasification of reductant, resulting in insufficient reducing atmosphere in the reduction process. The molten phase was formed at high temperatures of 1250-1 300℃, which accelerated the migration rate of metallic particles and suppressed the diffusion of reduction gas, resulting in poor reduction. The optimum conditions for reducing TTM concentrate are as follows： molar ratio of C to Fe of 1.68, reduction time of 150 min, and reduction temperature of 1 200℃. Under these conditions, direct reduction iron powder, assaying 90.28 mass% TFe and 1.73 mass% TiO2 with iron recovery of 90.85%, and titanium concentrate, assaying 46.24 mass% TiO2 with TiO2 recovery of 91.15%, were obtained.
文摘Magnetic plant biomonitoring has been proven to be an effective tool in the assessment of air quality. Kuwait presents a unique environment due to its dry desert climatic conditions and prevailing dry deposition patterns that may affect accumulation rates of magnetic mineral particles. This study evaluated two widely distributed ornamental species, buttonwood (Conocarpus erectus) and palm (Phoenix dactylifera) for their effectiveness as biomagnetic monitors over three different land use classes (urban, suburban and industrial land classes). The differences between land use classes were classified by their proximity to major pollution sources as well as population density. Leaf sampling was conducted over various heights and distances from the nearest road. Total leaf saturated isothermal magnetization (SIRM), hard isothermal magnetization (HIRM), hard isothermal magnetization percentage (HIRM%) and s-ratio have been measured. Scanning electron microscopy (SEM) was used to analyze leaf surface micromorphology. It was determined that NRM values are similar for all land use classes and species, ranging from 0.3 to 0.5 μA. Palm leaf overall magnetic concentration was identified to be higher at the industrial land use class than at the urban land use class, indicating high coercivity minerals to magnetically dominate the land use classes. Additionally, total leaf SIRM was determined to be higher at short distances of 0 - 5 meters from the vicinity of the road. The surface rugosity of palm has deep ridges and furrows with ununiform wax projections across the leaf surface, while buttonwood has a smooth wax film with low relief. Differences in leaf micromorphology in addition to plant physiology, justify species magnetic parametric variances. Palm leaf had an average SIRM value that is 120% higher than buttonwood. It has been highlighted that through the application of the magnetic parameter results to spatial distribution maps that there is an association between particulate matter (PM) and the locality of main roads and local services that may experience higher intensities of traffic.
基金the National Research Foundation of Korea(NRFe2022R1F1A1073594).D.-Y Jeong thanks for the financial support from Inha University.
文摘A cantilever-structured magneto-mechano-electric(MME)generator comprising a magnetoelectric composite with a magnet proof mass is a potential candidate for powering autonomous wireless sensor networks.Recently,the concept of a magnetic flux concentrator(MFC)to enhance the output performance of the MME generator by focusing the ultralow-intensity magnetic field into the MME generator was introduced.However,the MFC-concentrated magnetic flux mostly focused on the end tip of the MME cantilever rather than at the magnet proof mass located on the cantilever beam.Considering that the torque generated by the magnet proof mass contributes more than half of the output power of an MME generator,optimizing the volume and position of the proof-mass with MFC is crucial for better performance.Furthermore,a smaller proof-mass is desirable for the long-term reliability of cantilevertype harvesters.Hence,we investigated the effect of the position and weight(volume)of the magnet proof mass with respect to the MFC on the output performance of the MME generator through finite element analysis and experiments.The MME generator with the lighter magnet proof mass at the optimized position generated a maximum power of 5.35 mW under a 10 Oe magnetic field,which was 210%of that of the MME configuration used in our previous study.Furthermore,the MME generator showed broadband characteristics around the practical frequency of 60 Hz,which could provide more freedom to design the harvester with high performance.
基金financially supported by the National High Technology Research and Development Program of China (No. 2012AA040602)the National Natural Science Foundation of China (No. 61374217)
文摘A passive current sensor,consisting of SmFe_(2)/PZT/SmFe_(2)self-biased magnetoelectric(ME)composite and Fe_(73.5)Cu_(1)Nb_(3)Si_(13.5)B_(9)nanocrystalline flux concentrator for weak current detection at power-line frequency,was fabricated and characterized.Giant magnetostrictive material of SmFe_(2)plate with large anisotropic constant provides a huge internal anisotropic field to bias the ME transducer in closed magnetic loop.Consequently,the additional magnetomotive force induced by the internal field and the corresponding increased effective permeabil-ity contribute to the improvement of the sensitivity.Experimental results demonstrate that the presented sensor has a higher sensitivity of 152 mV·A^(-1)at 50 Hz with a slight nonlinearity of~0.01%full scale(FS)and matches well with the predicted value.This presented current-sensing device exhibits approximately 2.3 times higher sensitivity than that of conventional ME composite with[Pb(Zr_(0.48),Ti_(0.52)O_(3)](PZT)and Terfenol-D plates serving as a key sensitive component.In addition,time stabilities of the presented sensor were evaluated for a long period of 72 h and analyzed through mathematical statistics method,and favorable stabilities with an uncertainty of 0.5μV are obtained in continuous 1 h testing.These results provide a significant advancement toward promising application of the tri-layer self-biased ME laminate for power-line elec-tric cords monitoring.
