The total content of light rare earth elements( LREEs) in the soil of navel orange orchards of Gannan area is greater than that of heavy rare earth elements( HREEs). Appropriate content of LREE can not only promote th...The total content of light rare earth elements( LREEs) in the soil of navel orange orchards of Gannan area is greater than that of heavy rare earth elements( HREEs). Appropriate content of LREE can not only promote the growth of navel oranges,and it is also conducive to human health. On the basis of exploring the correlations between the content of LREE in the soil of navel orange orchards of Gannan area and the contents of LREE in navel orange leaves and fruit,the influence mechanism of LREEs on the quality of navel oranges was revealed. In this study,with two Newhall navel orange orchards with different soil LREEs background levels in Xinfeng County as the research object,the changes in the content of LREE( lanthanum,La; cerium,Ce; praseodymium,Pr; neodymium,Nd) in leaves and fruit of navel orange at different growth stages were analyzed using Inductively Coupled Plasma-Mass Spectrometry( ICP-MS),and the correlations between the content of LREE in the soil,navel orange leaves and navel orange fruit were studied. The results showed that the contents of the four kinds of LREEs in the soil ranked as Ce > La > Nd > Pr,and there were significant differences among them( P < 0. 01). Navel orange leaves and fruit have selective and heterogenic absorption for LREEs. At different growth stages,La showed the highest accumulation amount in the leaves and fruit of navel orange; and the content of LREE in the leaves of navel orange increased first and then decreased,while that in the fruit of navel orange showed continuous decrease. During the migration of LREEs from soil to leaves to fruit,the content of LREE decreased rapidly as the migration distance increased. The accumulation amount of LREE in navel orange was positively correlated with the content of LREE in the soil. The correlation between the content of LREE in the leaves and fruit of navel orange was greatest. Among the four kinds of LREEs,the correlation of La was greatest,followed by Ce,indicating that the accumulation amount of LREE in the navel orange body was affected by the element types.展开更多
The present paper proposes a new method of spectrophotometry based on linear combination of multiwavelength data by means of selecting a set of properly weighted coefficients and combination methods. It is clear that ...The present paper proposes a new method of spectrophotometry based on linear combination of multiwavelength data by means of selecting a set of properly weighted coefficients and combination methods. It is clear that the weighted combination absorbance attained is only in direct proportion to the concentration of the analysed component and independent of coexisting interferents.The accuracy of the analytical results is improved greatly for the analysis of light rare earths with the coexistence of heavy rare earths.The analyti- cal error from the reagent blank and co-coloration of light and heavy rare earths have also been overcome. The greatly improved linearity and additivity of absorbance are obtained.展开更多
Rare earth resources are relatively scarce worldwide, but their global consumption is increasing year-by-year. At present, China has about 36% of the global rare earth reserves, but provides 90% of the world's supply...Rare earth resources are relatively scarce worldwide, but their global consumption is increasing year-by-year. At present, China has about 36% of the global rare earth reserves, but provides 90% of the world's supply, which has generally met world demand and promoted the development of the world economy. In order to continuously and stably supply rare earths to international markets, the Chinese Government has financially supported the Institute of Multipurpose Utilization of Mineral Resources within the China Geological Survey to study the utilization of low-grade rare earth ores. Following many years of experimental research, the project has developed a new technology entitled "Flotation to Form Agglomerates and then Magnetic Separation", which will bring a technological revolution to the world's light rare earth ore dressing.展开更多
A novel high sensihtity, small-volume photothermal intheence detector has beenintroduced for capillap zone electrophoresis separation analysis. The utility of thes sdriulboconstecheque for momtomp chelating reachon of...A novel high sensihtity, small-volume photothermal intheence detector has beenintroduced for capillap zone electrophoresis separation analysis. The utility of thes sdriulboconstecheque for momtomp chelating reachon of light rare earth with tribromoarsenazo has beenreported.展开更多
The effects of rare earths with different contents on anti-degradation of Y base heavy rare earths-magnesium and cerium base light rare earths-magnesium nodular cast iron were studied. Curves of the relationship betwe...The effects of rare earths with different contents on anti-degradation of Y base heavy rare earths-magnesium and cerium base light rare earths-magnesium nodular cast iron were studied. Curves of the relationship between the spheroidization grade of liguid iron treated by different nodulizers and holding time were obtained. The results show that the more the remains of the rare earth, the longer the anti-degradation time, the liquid iron was treated either by Y-Mg-Si or by Ce-Mg-Si nodulizer. When the rare earth remains are above certain quantity, the spheroidization grade starts to decline. When liquid iron treated by either Y-Mg-Si or Ce-Mg-Si nodulizer with proper remains of rare earths about 0.04% 0.06%(mass fraction), the anti-degradation is the best, and the remains of Mg being about 0.04% -0.07% (mass fraction). Rare earths-Mg nodulizer with moderate RE remains is better than that of Mg-Si nodulizer in anti-degradation property. However, Y-Mg-Si nodulizer with moderate remins of Re is better than Ce-Mg-Si nodulizer. Sometimes Ce-Mg- Si nodulizer can be used for the production of heavy section nodular cast iron.展开更多
At present, the use of rare earth elements(REEs) has become an inevitable necessity in many modern industries. In general, liquid extraction is the best commercial method for extracting REEs due to its ability to co...At present, the use of rare earth elements(REEs) has become an inevitable necessity in many modern industries. In general, liquid extraction is the best commercial method for extracting REEs due to its ability to control high volumes of liquids with electrical load. With the aim of improving a separation technology that would be superior to the existing extraction systems, the extraction behaviors of La(Ⅲ),Pr(Ⅲ), and Nd(Ⅲ) from an HCI medium with Cyanex 272 in the presence of the complexing agent lactic acid(HLac) and auxiliary agents citric acid(H3 Cit), acetic acid(HAc), and Titriplex Ⅲ have been reported.The effect of pH and lactic acid concentration has been examined. The use of lactic acid as a complexing agent leading to a high extraction of REEs with Cyanex 272 at pH = 5 was compared with systems without lactic acid. The results show that the use of acetic acid along with lactic acid leads to an increase in the extraction percentage of LREEs. While use of citric acid and Titriplex Ⅲ reduces the extraction percentage of LREEs. Finally, the presence of Titriplex Ⅲ together with lactic acid could lead to an increase in the separation factor of Pr and Nd.展开更多
Remarkable progress was made in the development of white-light-emitting diodes (LEDs). White LEDs provided a light element having a semiconductor InGaN light-emitting chip (blue or UV LEDs) and luminescent phospho...Remarkable progress was made in the development of white-light-emitting diodes (LEDs). White LEDs provided a light element having a semiconductor InGaN light-emitting chip (blue or UV LEDs) and luminescent phosphors. Here we reported the sialon s-phase of (Sr,Eu)2A12Si10N14O4. Eu^2+ activator ions that were substituted for the strontium site represented a new type of yeUow-green phosphor that could be excited by blue LEDs used for application in the fabrication of white LEDs.展开更多
Solid-state white LED will be a new generation of energy-saving light source in 21 century. In order to emitting white light, one of important approaches is using luminescence conversion technology with rare earth pho...Solid-state white LED will be a new generation of energy-saving light source in 21 century. In order to emitting white light, one of important approaches is using luminescence conversion technology with rare earth phosphors, which can be excited by the 460 nm blue light or 400 nm near violet light emitted from the InGaN chip and then emit white light. The rare earths doped phosphors prepared by us such as YAG : Ce^3+, Ca1-xSrxS : Eu^2+, Ga2S3 : Eu^2+, MGa2S4:Eu^2+ (M = Ca, Sr, Ba), SrGa2+xS4+y :Eu^2+,(Ca1 - xSrx ) Se : Eu^2 + , SrLaGaaS6O : Eu^2 + , ( M1, M2 ) 10 (PO4)6XE(M1 = Ca, Sr, Ba; Ms = Eu, Mn; X = F, Cl, Br) and NaEu0.92 Sm0.08 (MoO4)5 were reported. They emit blue, green, yellow or red color light. Some white LEDs were made by these phosphors with blue or near violet InGaN chips and their chromaticity coordinate (x, y), correlated color temperature Tc, and color rendering index Ra are reported.展开更多
Rare earth-doped oxide thin-film phosphors may emerge as an alternate choice for the blue phosphor, due to their chemical and thermal stability in high vacuum and absence of corrosive gas emission under electron bomba...Rare earth-doped oxide thin-film phosphors may emerge as an alternate choice for the blue phosphor, due to their chemical and thermal stability in high vacuum and absence of corrosive gas emission under electron bombardment. The blue phosphors in this study were activated in air at temperatures suitable for glass substrates, which have been used in a number of applications. The effects of rare earth ions and oxide hosts on the blue-light-emitting properties of phosphors are discussed. In addition, novel blue-light emission was observed in certain typical undoped wide bandgap oxides. The luminescence of the oxides depends on the growth and annealing conditions under different atmospheres, suggesting that it is associated with the presence of oxygen vacancies. Radiative processes related to oxygen vacancies were also presented.展开更多
Different separation techniques such as solvent extraction, ion exchange, and precipitation are often used for recovery of rare earth elements (REEs) from pregnant leach solutions obtained from acid leaching. Solvent ...Different separation techniques such as solvent extraction, ion exchange, and precipitation are often used for recovery of rare earth elements (REEs) from pregnant leach solutions obtained from acid leaching. Solvent extraction is generally accepted as the most appropriate commercial technology for separating REEs due to the need to be able to handle larger volumes of diluted pregnant solutions. This study focused on the development of selective separation of light and heavy REEs from the pregnant leach solution obtained from leaching of apatite ore in 1 M sulfuric acid (H2SO4) using solvent extraction. Three different commercial organophosphorus extractants (di-(2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC88A) and tributyl phosphate (TBP)), and the influences of experimental parameters such as extractant concentration, organic/aqueous phase ratio, diluent type, pH, extraction time and stripping agent concentration were examined. Results showed that light REEs (LREEs) and heavy REEs (HREEs) in the pregnant leach solution were selectively separated with D2EHPA via a two-stage extraction process. In the first-stage of solvent extraction, >90% of (0.05 g/L) HREEs was extracted with 1.8 M D2EHPA in kerosene while the vast majority (>95%) of LREEs was remained in raffinate. In the second-stage, >93% (1.01 g/L) of LREEs was extracted from the raffinate with 1.8 M D2EHPA dissolved in kerosene at pH 1.6. HREEs (>95%) and LREEs (>90%) loaded with D2EHPA after the first and second-stage of extraction were stripped by 4 M H2SO4 and 1 M H2SO4 solutions, respectively. Distribution of middle rare earth elements (MREEs) was discussed through the extraction processes in this study.展开更多
A review of crystallochemical thermodynamic and phase diagram data of Mg RE and Al RE based systems is presented. On the basis also of their possible applications, special attention is given to the Mg rich and Al ...A review of crystallochemical thermodynamic and phase diagram data of Mg RE and Al RE based systems is presented. On the basis also of their possible applications, special attention is given to the Mg rich and Al rich alloys and to the effects of rare earth additions on their properties. A summary of the experimental work carried out by our research group on several binary and ternary alloys is reported: that is Mg RE, Al RE, and Mg RE RE′ and Al RE RE′ with two different rare earth metals. A number of regularities observed in the formation and in the crystallochemistry of binary and ternary Mg rich or Al rich phases are summarised and discussed. Their application to a fine planning of alloys having a well defined structure is suggested.展开更多
Under reduction atmosphere, a blue sky rare earth silicate light storage and emission material was prepared by high temperature solid phase synthesis. The best constituent ratio of this material was determined through...Under reduction atmosphere, a blue sky rare earth silicate light storage and emission material was prepared by high temperature solid phase synthesis. The best constituent ratio of this material was determined through orthogonal experiment, and its excitation and emission spectra and X-ray diffraction patterns were measured. And a comparative study was conducted on its application properties.展开更多
The interaction of ternary complexes [RE(phen)(cin)_3(H_2O)](RE= Nd (III),Ce(III),Eu(III))with calf thymus DNA was investigated by electronic absorption spectroscopy, ethidium bromide(EB)-DNA quenching fluorescent spe...The interaction of ternary complexes [RE(phen)(cin)_3(H_2O)](RE= Nd (III),Ce(III),Eu(III))with calf thymus DNA was investigated by electronic absorption spectroscopy, ethidium bromide(EB)-DNA quenching fluorescent spectra and resonance light scattering. All experimental results indicate that the three complexes bind to DNA by the electrostatic mode and the intercalative mode. It is predicted that these complexes show high anticancer activity or other biologic activity.展开更多
基金Supported by National Natural Science Foundation of China(31760551)Jiangxi Natural Science Foundation(20152ACB21002)Collaborative Innovation Special Funds of Jiangxi Academy of Sciences(2013-XTPH1-05)
文摘The total content of light rare earth elements( LREEs) in the soil of navel orange orchards of Gannan area is greater than that of heavy rare earth elements( HREEs). Appropriate content of LREE can not only promote the growth of navel oranges,and it is also conducive to human health. On the basis of exploring the correlations between the content of LREE in the soil of navel orange orchards of Gannan area and the contents of LREE in navel orange leaves and fruit,the influence mechanism of LREEs on the quality of navel oranges was revealed. In this study,with two Newhall navel orange orchards with different soil LREEs background levels in Xinfeng County as the research object,the changes in the content of LREE( lanthanum,La; cerium,Ce; praseodymium,Pr; neodymium,Nd) in leaves and fruit of navel orange at different growth stages were analyzed using Inductively Coupled Plasma-Mass Spectrometry( ICP-MS),and the correlations between the content of LREE in the soil,navel orange leaves and navel orange fruit were studied. The results showed that the contents of the four kinds of LREEs in the soil ranked as Ce > La > Nd > Pr,and there were significant differences among them( P < 0. 01). Navel orange leaves and fruit have selective and heterogenic absorption for LREEs. At different growth stages,La showed the highest accumulation amount in the leaves and fruit of navel orange; and the content of LREE in the leaves of navel orange increased first and then decreased,while that in the fruit of navel orange showed continuous decrease. During the migration of LREEs from soil to leaves to fruit,the content of LREE decreased rapidly as the migration distance increased. The accumulation amount of LREE in navel orange was positively correlated with the content of LREE in the soil. The correlation between the content of LREE in the leaves and fruit of navel orange was greatest. Among the four kinds of LREEs,the correlation of La was greatest,followed by Ce,indicating that the accumulation amount of LREE in the navel orange body was affected by the element types.
文摘The present paper proposes a new method of spectrophotometry based on linear combination of multiwavelength data by means of selecting a set of properly weighted coefficients and combination methods. It is clear that the weighted combination absorbance attained is only in direct proportion to the concentration of the analysed component and independent of coexisting interferents.The accuracy of the analytical results is improved greatly for the analysis of light rare earths with the coexistence of heavy rare earths.The analyti- cal error from the reagent blank and co-coloration of light and heavy rare earths have also been overcome. The greatly improved linearity and additivity of absorbance are obtained.
文摘Rare earth resources are relatively scarce worldwide, but their global consumption is increasing year-by-year. At present, China has about 36% of the global rare earth reserves, but provides 90% of the world's supply, which has generally met world demand and promoted the development of the world economy. In order to continuously and stably supply rare earths to international markets, the Chinese Government has financially supported the Institute of Multipurpose Utilization of Mineral Resources within the China Geological Survey to study the utilization of low-grade rare earth ores. Following many years of experimental research, the project has developed a new technology entitled "Flotation to Form Agglomerates and then Magnetic Separation", which will bring a technological revolution to the world's light rare earth ore dressing.
文摘A novel high sensihtity, small-volume photothermal intheence detector has beenintroduced for capillap zone electrophoresis separation analysis. The utility of thes sdriulboconstecheque for momtomp chelating reachon of light rare earth with tribromoarsenazo has beenreported.
文摘The effects of rare earths with different contents on anti-degradation of Y base heavy rare earths-magnesium and cerium base light rare earths-magnesium nodular cast iron were studied. Curves of the relationship between the spheroidization grade of liguid iron treated by different nodulizers and holding time were obtained. The results show that the more the remains of the rare earth, the longer the anti-degradation time, the liquid iron was treated either by Y-Mg-Si or by Ce-Mg-Si nodulizer. When the rare earth remains are above certain quantity, the spheroidization grade starts to decline. When liquid iron treated by either Y-Mg-Si or Ce-Mg-Si nodulizer with proper remains of rare earths about 0.04% 0.06%(mass fraction), the anti-degradation is the best, and the remains of Mg being about 0.04% -0.07% (mass fraction). Rare earths-Mg nodulizer with moderate RE remains is better than that of Mg-Si nodulizer in anti-degradation property. However, Y-Mg-Si nodulizer with moderate remins of Re is better than Ce-Mg-Si nodulizer. Sometimes Ce-Mg- Si nodulizer can be used for the production of heavy section nodular cast iron.
基金Project supported by Anguran Lead and Zinc Company(55/G/93)
文摘At present, the use of rare earth elements(REEs) has become an inevitable necessity in many modern industries. In general, liquid extraction is the best commercial method for extracting REEs due to its ability to control high volumes of liquids with electrical load. With the aim of improving a separation technology that would be superior to the existing extraction systems, the extraction behaviors of La(Ⅲ),Pr(Ⅲ), and Nd(Ⅲ) from an HCI medium with Cyanex 272 in the presence of the complexing agent lactic acid(HLac) and auxiliary agents citric acid(H3 Cit), acetic acid(HAc), and Titriplex Ⅲ have been reported.The effect of pH and lactic acid concentration has been examined. The use of lactic acid as a complexing agent leading to a high extraction of REEs with Cyanex 272 at pH = 5 was compared with systems without lactic acid. The results show that the use of acetic acid along with lactic acid leads to an increase in the extraction percentage of LREEs. While use of citric acid and Titriplex Ⅲ reduces the extraction percentage of LREEs. Finally, the presence of Titriplex Ⅲ together with lactic acid could lead to an increase in the separation factor of Pr and Nd.
基金Project supported by the Economic Affair (95-EC-17-A-07-S1-043)the National Science Council (94-2113-M-002-030)
文摘Remarkable progress was made in the development of white-light-emitting diodes (LEDs). White LEDs provided a light element having a semiconductor InGaN light-emitting chip (blue or UV LEDs) and luminescent phosphors. Here we reported the sialon s-phase of (Sr,Eu)2A12Si10N14O4. Eu^2+ activator ions that were substituted for the strontium site represented a new type of yeUow-green phosphor that could be excited by blue LEDs used for application in the fabrication of white LEDs.
文摘Solid-state white LED will be a new generation of energy-saving light source in 21 century. In order to emitting white light, one of important approaches is using luminescence conversion technology with rare earth phosphors, which can be excited by the 460 nm blue light or 400 nm near violet light emitted from the InGaN chip and then emit white light. The rare earths doped phosphors prepared by us such as YAG : Ce^3+, Ca1-xSrxS : Eu^2+, Ga2S3 : Eu^2+, MGa2S4:Eu^2+ (M = Ca, Sr, Ba), SrGa2+xS4+y :Eu^2+,(Ca1 - xSrx ) Se : Eu^2 + , SrLaGaaS6O : Eu^2 + , ( M1, M2 ) 10 (PO4)6XE(M1 = Ca, Sr, Ba; Ms = Eu, Mn; X = F, Cl, Br) and NaEu0.92 Sm0.08 (MoO4)5 were reported. They emit blue, green, yellow or red color light. Some white LEDs were made by these phosphors with blue or near violet InGaN chips and their chromaticity coordinate (x, y), correlated color temperature Tc, and color rendering index Ra are reported.
基金Project supported bythe National Natural Science Foundation of China (50472079)
文摘Rare earth-doped oxide thin-film phosphors may emerge as an alternate choice for the blue phosphor, due to their chemical and thermal stability in high vacuum and absence of corrosive gas emission under electron bombardment. The blue phosphors in this study were activated in air at temperatures suitable for glass substrates, which have been used in a number of applications. The effects of rare earth ions and oxide hosts on the blue-light-emitting properties of phosphors are discussed. In addition, novel blue-light emission was observed in certain typical undoped wide bandgap oxides. The luminescence of the oxides depends on the growth and annealing conditions under different atmospheres, suggesting that it is associated with the presence of oxygen vacancies. Radiative processes related to oxygen vacancies were also presented.
文摘Different separation techniques such as solvent extraction, ion exchange, and precipitation are often used for recovery of rare earth elements (REEs) from pregnant leach solutions obtained from acid leaching. Solvent extraction is generally accepted as the most appropriate commercial technology for separating REEs due to the need to be able to handle larger volumes of diluted pregnant solutions. This study focused on the development of selective separation of light and heavy REEs from the pregnant leach solution obtained from leaching of apatite ore in 1 M sulfuric acid (H2SO4) using solvent extraction. Three different commercial organophosphorus extractants (di-(2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC88A) and tributyl phosphate (TBP)), and the influences of experimental parameters such as extractant concentration, organic/aqueous phase ratio, diluent type, pH, extraction time and stripping agent concentration were examined. Results showed that light REEs (LREEs) and heavy REEs (HREEs) in the pregnant leach solution were selectively separated with D2EHPA via a two-stage extraction process. In the first-stage of solvent extraction, >90% of (0.05 g/L) HREEs was extracted with 1.8 M D2EHPA in kerosene while the vast majority (>95%) of LREEs was remained in raffinate. In the second-stage, >93% (1.01 g/L) of LREEs was extracted from the raffinate with 1.8 M D2EHPA dissolved in kerosene at pH 1.6. HREEs (>95%) and LREEs (>90%) loaded with D2EHPA after the first and second-stage of extraction were stripped by 4 M H2SO4 and 1 M H2SO4 solutions, respectively. Distribution of middle rare earth elements (MREEs) was discussed through the extraction processes in this study.
文摘A review of crystallochemical thermodynamic and phase diagram data of Mg RE and Al RE based systems is presented. On the basis also of their possible applications, special attention is given to the Mg rich and Al rich alloys and to the effects of rare earth additions on their properties. A summary of the experimental work carried out by our research group on several binary and ternary alloys is reported: that is Mg RE, Al RE, and Mg RE RE′ and Al RE RE′ with two different rare earth metals. A number of regularities observed in the formation and in the crystallochemistry of binary and ternary Mg rich or Al rich phases are summarised and discussed. Their application to a fine planning of alloys having a well defined structure is suggested.
文摘Under reduction atmosphere, a blue sky rare earth silicate light storage and emission material was prepared by high temperature solid phase synthesis. The best constituent ratio of this material was determined through orthogonal experiment, and its excitation and emission spectra and X-ray diffraction patterns were measured. And a comparative study was conducted on its application properties.
文摘The interaction of ternary complexes [RE(phen)(cin)_3(H_2O)](RE= Nd (III),Ce(III),Eu(III))with calf thymus DNA was investigated by electronic absorption spectroscopy, ethidium bromide(EB)-DNA quenching fluorescent spectra and resonance light scattering. All experimental results indicate that the three complexes bind to DNA by the electrostatic mode and the intercalative mode. It is predicted that these complexes show high anticancer activity or other biologic activity.