To achieve the utilization of the abandoned ultrafine ilmenite(-20 μm) produced in the titanium magnetite processing plant in Panzhihua,the superconducting high-gradient magnetic separation(SMS) technology was propos...To achieve the utilization of the abandoned ultrafine ilmenite(-20 μm) produced in the titanium magnetite processing plant in Panzhihua,the superconducting high-gradient magnetic separation(SMS) technology was proposed in this study.After optimizing the conditions of magnetic intensity,feeding and pulsation,an SMS concentrate with TiO_(2) grade of 16.03% and TiO_(2) recovery of 66.39% was obtained through one roughing-one cleaning pre-concentration flowsheet.The specific magnetic force and magnetic force were calculated and analysed to illustrate the pre-concentration mechanism,and the results revealed that the combination of high magnetic field and strong pulsating resulted in the effective preconcentration of the ultrafine ilmenite in the SMS process.In addition,the magnetic force analysis indicated that the high magnetic intensity and high magnetic gradient are the key factors of the SMS technology.Furthermore,the EDS-Mapping detection certified that the ultrafine ilmenite was concentrated from the gangue minerals using SMS technology.展开更多
We synthesize a series of Mn substituted （Li, Fe）OHFeSe superconductor single crystals via a modified ion-exchange method, with the Mn concentration z （the atomic ratio of Mn：Se） ranging from 0 to 0.07. The distr...We synthesize a series of Mn substituted （Li, Fe）OHFeSe superconductor single crystals via a modified ion-exchange method, with the Mn concentration z （the atomic ratio of Mn：Se） ranging from 0 to 0.07. The distribution homogeneity of the Mn element incorporated into the lattice of （Li, Fe）OHFeSe is checked by combined measurements of high-angle- annular-dark-field （HAADF） imaging and electron energy-loss spectroscopy （EELS）. Interestingly, we find that the superconducting transition temperature Tc and unit cell parameter c of the Mn-doped （Li, Fe）OHFeSe samples display similar V-shaped evolutions with the increasing dopant concentration z. We propose that, with increasing doping level, the Mn dopant first occupies the tetrahedral sites in the （Li, Fe）OH layers before starting to substitute the Fe element in the su- perconducting FeSe layers, which accounts for the V-shaped change in cell parameter c. The observed positive correlation between the Tc and lattice parameter c, regardless of the Mn doping level z, indicates that a larger interlayer separation, or a weaker interlayer coupling, is essential for the high-Tc superconductivity in （Li, Fe）OHFeSe. This agrees with our previous observations on powder, single crystal, and film samples of （Li, Fe）OHFeSe superconductors.展开更多
A new muon beam facility,called the Experimental Muon Source(EMuS),was proposed for construction at the China Spallation Neutron Source(CSNS).The design of the complex muon beamlines for the EMuS baseline scheme,which...A new muon beam facility,called the Experimental Muon Source(EMuS),was proposed for construction at the China Spallation Neutron Source(CSNS).The design of the complex muon beamlines for the EMuS baseline scheme,which is based on superconducting solenoids,superferric dipoles and room-temperature magnets,is presented herein.Various muon beams,including surface muons,decay muons and low energy muons,have been developed for multipurpose applications.The optics design and simulation results of the trunk beamline and branch beamlines are presented.With a proton beam power of 25 kW at a standalone target station that consists of a conical graphite target and high-field superconducting solenoids,the muon beam intensity in the trunk beamline varies from 10^(7)/s for surface muons to 10^(10)/s for high-momentum decay muons.And at the endstations,these values vary from 10^(5)/s for surface muons to 10^(8)/s for decay muons.展开更多
基金financial support from the Joint Fund (Key program U2067201) for Nuclear Technology Innovation Sponsored by the National Natural Science Foundation of China and the China National Nuclear CorporationNational key research and development program (2019YFC1907702) Sponsored by MOSTthe Fundamental Research Funds for the Central Universities (N2001013) for supporting this research。
文摘To achieve the utilization of the abandoned ultrafine ilmenite(-20 μm) produced in the titanium magnetite processing plant in Panzhihua,the superconducting high-gradient magnetic separation(SMS) technology was proposed in this study.After optimizing the conditions of magnetic intensity,feeding and pulsation,an SMS concentrate with TiO_(2) grade of 16.03% and TiO_(2) recovery of 66.39% was obtained through one roughing-one cleaning pre-concentration flowsheet.The specific magnetic force and magnetic force were calculated and analysed to illustrate the pre-concentration mechanism,and the results revealed that the combination of high magnetic field and strong pulsating resulted in the effective preconcentration of the ultrafine ilmenite in the SMS process.In addition,the magnetic force analysis indicated that the high magnetic intensity and high magnetic gradient are the key factors of the SMS technology.Furthermore,the EDS-Mapping detection certified that the ultrafine ilmenite was concentrated from the gangue minerals using SMS technology.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFA0303003 and 2016YFA0300300)the National Natural Science Foundation of China(Grant No.11574370)the Strategic Priority Research Program and Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(Grant Nos.QYZDY-SSW-SLH001,QYZDY-SSW-SLH008,and XDB07020100)
文摘We synthesize a series of Mn substituted （Li, Fe）OHFeSe superconductor single crystals via a modified ion-exchange method, with the Mn concentration z （the atomic ratio of Mn：Se） ranging from 0 to 0.07. The distribution homogeneity of the Mn element incorporated into the lattice of （Li, Fe）OHFeSe is checked by combined measurements of high-angle- annular-dark-field （HAADF） imaging and electron energy-loss spectroscopy （EELS）. Interestingly, we find that the superconducting transition temperature Tc and unit cell parameter c of the Mn-doped （Li, Fe）OHFeSe samples display similar V-shaped evolutions with the increasing dopant concentration z. We propose that, with increasing doping level, the Mn dopant first occupies the tetrahedral sites in the （Li, Fe）OH layers before starting to substitute the Fe element in the su- perconducting FeSe layers, which accounts for the V-shaped change in cell parameter c. The observed positive correlation between the Tc and lattice parameter c, regardless of the Mn doping level z, indicates that a larger interlayer separation, or a weaker interlayer coupling, is essential for the high-Tc superconductivity in （Li, Fe）OHFeSe. This agrees with our previous observations on powder, single crystal, and film samples of （Li, Fe）OHFeSe superconductors.
基金supported by the National Natural Science Foundation of China(Nos.11527811 and 12035017).
文摘A new muon beam facility,called the Experimental Muon Source(EMuS),was proposed for construction at the China Spallation Neutron Source(CSNS).The design of the complex muon beamlines for the EMuS baseline scheme,which is based on superconducting solenoids,superferric dipoles and room-temperature magnets,is presented herein.Various muon beams,including surface muons,decay muons and low energy muons,have been developed for multipurpose applications.The optics design and simulation results of the trunk beamline and branch beamlines are presented.With a proton beam power of 25 kW at a standalone target station that consists of a conical graphite target and high-field superconducting solenoids,the muon beam intensity in the trunk beamline varies from 10^(7)/s for surface muons to 10^(10)/s for high-momentum decay muons.And at the endstations,these values vary from 10^(5)/s for surface muons to 10^(8)/s for decay muons.
