Polycrystalline tungsten（W）and molybdenum（Mo）materials both non-annealed and annealed at temperatures of 800-1750~C have been irradiated with low-energy（220 eV）,high-flux（~10^（21）ions/m^2.s）He~＋at an irradi...Polycrystalline tungsten（W）and molybdenum（Mo）materials both non-annealed and annealed at temperatures of 800-1750~C have been irradiated with low-energy（220 eV）,high-flux（~10^（21）ions/m^2.s）He~＋at an irradiation temperature of 600℃and at a dose of1.0×10^（25）ions/m^2.This non-destructive conductive atomic force microscopy technique provides direct observation and comparison of surface swellings with growth of nanoscale defects in the irradiated materials.A coral-like surface structure and nanostructured defects were formed in W when irradiated at a He＋dose of 1.0×10^（25）ions/m^2.Increasing the annealing temperature resulted in an increase in the size of nanostructured defects and serious surface damage of W.Compared to W,Mo suffered much less surface damage after being irradiated at various He~＋doses.展开更多
The melting, evaporation and oxidation behaviors as well as the solidification phenomena of tungsten and molybdenum in induction plasma were studied. Scanning electron microscopy was used to examine the morphology and...The melting, evaporation and oxidation behaviors as well as the solidification phenomena of tungsten and molybdenum in induction plasma were studied. Scanning electron microscopy was used to examine the morphology and the cross section of plasma-processed powders. X-ray diffraction was used to analyze the oxides formed on the particle surface of these two metals. The influence of spray chamber pressure on the spheroidization and oxidation phenomena was discussed. The results show that fewer Mo particles than W particles are spheroidized at the same powder feed rate under the same plasma spray condition although molybdenum has a lower melting point. A small fraction of tungsten is evaporized and condensed either on the surface of tungsten particles nearby or on the wall of spray chamber. Tungsten oxides were found in tungsten powder processed under soft vacuum condition. Extremely large grains form inside some spheroidized particles of tungsten powder.展开更多
Several kinds of tungsten thermonic cathodes have been introduced. As a promising alternative for thoriated tungsten, rare earth doped molybdenum cathode has been studied. Compared with the traditional thoriated tungs...Several kinds of tungsten thermonic cathodes have been introduced. As a promising alternative for thoriated tungsten, rare earth doped molybdenum cathode has been studied. Compared with the traditional thoriated tungsten, La-Mo cathode has higher emission current density at lower temperature, but it has poor emission stability. In order to improve the emission stability, systematical study on the emission mechanism of La-Mo cathode has been carried out. The life of La-Mo cathode has been improved and has achieved 1400 It, which exceeds the minimum life for practical uses (1000 h). As another alternative for thoriated tungsten cathode, Y-Mo cathode has shown better performance. The thermionic emission capability of Y-Mo cathode is between that of La-Mo cathode and Th-W cathode.展开更多
This article introduces a method determining the equation of penetration curve by multielement regression(MER) in study of double glow discharge plasma metallizing(DGM) and the slope of the penetration curve can be ca...This article introduces a method determining the equation of penetration curve by multielement regression(MER) in study of double glow discharge plasma metallizing(DGM) and the slope of the penetration curve can be calculated by derivation,the xdy can also be obtained.This method is more reliable and accurate than graphical integration.The variation of diffusion coefficient with the concentration of W and Mo are determined.展开更多
The interaction of nitrilotriacetic acid （NTA） and iminodiacetic acid （IDA） with tungsten（VI） （pH 7.5） and molybdenum（VI） （pH 6.00） has been studied in aqueous solutions at 25℃, and different ionic streng...The interaction of nitrilotriacetic acid （NTA） and iminodiacetic acid （IDA） with tungsten（VI） （pH 7.5） and molybdenum（VI） （pH 6.00） has been studied in aqueous solutions at 25℃, and different ionic strengths （0.1 〈 1 （mol dm^-3） 〈 1.0 for NaClO4） by a combination of potentiometric and UV spectroscopic（260-270 nm） measurements. Dependence on ionic strength was taken into account by using the Bronsted-Guggenheim-Scatchard specific ion interaction theory （SIT） and parabolic model. The data included in this work, together with some previously published data, make it possible to calculate parameters for dependence on ionic strength by using the aforementioned models.展开更多
Research on the separation of tungstenand molybdenum is of importance as it is a ba-sic problem in the metallurgy and industry oftungsten.Traditional methods for the separa-tion include precipitation with sulfides and...Research on the separation of tungstenand molybdenum is of importance as it is a ba-sic problem in the metallurgy and industry oftungsten.Traditional methods for the separa-tion include precipitation with sulfides andsolvent extraction.There are,however,certaindisadvantages for these methods.A novelmethod was developed based on another展开更多
The title complex was obtained by reactions of [Mo(CO)_3(MeCN)_3] with [CuBr(pySH)(PPh_3)_2]or directly with pySH and PPh_3. The latter method can be used to synthesize the corresponding tungsten complex [W_2(CO)_4(μ...The title complex was obtained by reactions of [Mo(CO)_3(MeCN)_3] with [CuBr(pySH)(PPh_3)_2]or directly with pySH and PPh_3. The latter method can be used to synthesize the corresponding tungsten complex [W_2(CO)_4(μ-pyS)_2(PPh_3)_2].The molecular structure of the title compound was determined by X-ray diffraction method.展开更多
The Gaoaobei tungsten-molybdenum deposit is a newly discovered large-scale quartzvein-type deposit in the Nanling metallogenic belt in South China.The ore bodies are hosted in the Indosinian granites and the Cambrian ...The Gaoaobei tungsten-molybdenum deposit is a newly discovered large-scale quartzvein-type deposit in the Nanling metallogenic belt in South China.The ore bodies are hosted in the Indosinian granites and the Cambrian Xiangnan Group slates and are controlled by NWW-oriented faults,which are obviously different from the“five-story building”model in southern Jiangxi Province.The magmatic rocks in the study area are dominated by medium-to coarse-grained biotite monzogranite,with a few NW-oriented fine-grained granite dykes.The medium-to coarse-grained biotite monzogranite and fine-grained granite dykes have zircon U-Pb ages of 229.4±1.9 Ma(MSWD=1.5)and 164.9±3.3 Ma(MSWD=0.75),respectively,corresponding to the Indosinian and Yanshanian magmatism.The monzogranites have higher contents of FeO,CaO,K2O,P2O5,and TiO2,while the granite dykes have slightly higher contents of SiO2,Al2O3,MnO,and Na2O.Their A/CNK values are 1.11-1.75 and 1.19-2.25,and the contents of CIPW normative corundum are 1.71%-6.66%and 2.41%-9.50%,suggesting both the monzogranites and granite dykes are S-type granite.The total amount of rare earth elements in the monzogranites(from 84.7 ppm to 129 ppm)is slightly lower than that in the granite dykes(from 128 ppm to 133 ppm).The Eu/Eu*values range from 0.12 to 0.30 in monzogranites and from 0.0011 to 0.0013 in granite dykes,indicating the fine-grained granites underwent more intense fractional crystallization.The monzogranite and granite dykes have high 87Sr/86Sri values of 0.7169-0.7193 and 0.72825-0.72880,lowεNd(t)values ranging from-10.2 to-9.6 and from-11.5 to-11.4,and TDM2 ages of 1835-1785 and 1957-1946 Ma,respectively.These isotope data indicate their origin from the remelting of the Paleoproterozoic crustal materials.Combined with regional geology,it is concluded that the medium-to coarse-grained biotite monzogranite was formed in a post-collisional extensional environment.In addition,40Ar-39Ar dating of the greisen type tungsten-molybdenum ore gave consistent plateau age of 164.0±1.2 Ma,isochronal age of 162.0±2.4 Ma and anti-isochronal age of 161.4±1.8 Ma.Combined with the published molybdenite Re-Os age,the Gaoaobei tungsten-molybdenum deposit was formed at~164 Ma,which is inferred to be genetically related to the contemporaneous finegrained granite dykes(165 Ma).The deposit was likely formed during the large-scale magmatism and mineralization event in the early Yanshanian of the Nanling Range in an intra-continental extensional environment caused by the subduction of the paleo-Pacific plate.The late and small granite dykes within the large granite plutons thus require further attention during mineral prospecting in the regions.展开更多
试验采用高分辨率电感耦合等离子体质谱法(High-Resolution Inductively Coupled Plasma Mass Spectrometry,HR-ICP-MS)测定钨钼矿石中钨、钼、锂、铬、钴、镍、铜、锌、镓、锗、砷、硒、铷、铌、铟、锡、锑、铼、铊和铋等元素的含量。...试验采用高分辨率电感耦合等离子体质谱法(High-Resolution Inductively Coupled Plasma Mass Spectrometry,HR-ICP-MS)测定钨钼矿石中钨、钼、锂、铬、钴、镍、铜、锌、镓、锗、砷、硒、铷、铌、铟、锡、锑、铼、铊和铋等元素的含量。参考国家一级标准物质,对HR-ICP-MS进行数据比较和精确度验证,按照相关标准规定的方法确定HR-ICP-MS的检出限。结果表明,采用HR-ICP-MS测量钨钼矿石金属元素的相对标准偏差(Relative Standard Deviation,RSD)为0.86%~9.70%,各元素的检出限介于0.002~27.000 mg/kg,加标试验后的回收率损失小于2%,该方法可靠可信,准确度和精密度都能达到测试要求。展开更多
研究了采用ZGA351大孔强碱性阴离子交换树脂从粗钨酸铵溶液中吸附分离钼的工艺方法,考察了树脂型号、料液硫含量、料液陈化时间、料液陈化温度、料液pH值、吸附流速、吸附温度对树脂吸附分离钼效果的影响。结果表明:使用100 mL ZGA351...研究了采用ZGA351大孔强碱性阴离子交换树脂从粗钨酸铵溶液中吸附分离钼的工艺方法,考察了树脂型号、料液硫含量、料液陈化时间、料液陈化温度、料液pH值、吸附流速、吸附温度对树脂吸附分离钼效果的影响。结果表明:使用100 mL ZGA351树脂进行动态吸附试验,在料液硫含量为理论量1.1倍、料液陈化时间48 h、料液陈化温度40℃、料液pH值10.0、吸附流速15 mL/h、吸附温度40℃的最优条件下,料液钨损失率仅为0.54%,树脂钼穿透容量为107.77 g/L_(湿树脂),相比目前工业生产应用的HBDM-1树脂钼穿透容量提高了3.15倍。另外,重复试验稳定性良好,ZGA351树脂吸附后得到的纯钨酸铵溶液平均钼钨比为0.88×10^(-4),满足工业生产APT产品用纯钨酸铵溶液钼钨比小于2×10^(-4)的需求。综合而言,采用强碱性阴离子交换树脂从粗钨酸铵溶液中分离钼具有钼穿透容量高、钨损失率低、钨钼分离效率高等优势,为工业化应用提供了一种有效技术参考。展开更多
基金supported by the National Magnetic Confinement Fusion Program of China(No.2011GB108011)National Natural Science Foundation of China(No.11405023)+1 种基金the Scientific Research Fund of Liaoning Provincial Education Department(No.L2014539)the Fundamental Research Funds for the Central Universities of China(No.DC201502080410)
文摘Polycrystalline tungsten（W）and molybdenum（Mo）materials both non-annealed and annealed at temperatures of 800-1750~C have been irradiated with low-energy（220 eV）,high-flux（~10^（21）ions/m^2.s）He~＋at an irradiation temperature of 600℃and at a dose of1.0×10^（25）ions/m^2.This non-destructive conductive atomic force microscopy technique provides direct observation and comparison of surface swellings with growth of nanoscale defects in the irradiated materials.A coral-like surface structure and nanostructured defects were formed in W when irradiated at a He＋dose of 1.0×10^（25）ions/m^2.Increasing the annealing temperature resulted in an increase in the size of nanostructured defects and serious surface damage of W.Compared to W,Mo suffered much less surface damage after being irradiated at various He~＋doses.
文摘The melting, evaporation and oxidation behaviors as well as the solidification phenomena of tungsten and molybdenum in induction plasma were studied. Scanning electron microscopy was used to examine the morphology and the cross section of plasma-processed powders. X-ray diffraction was used to analyze the oxides formed on the particle surface of these two metals. The influence of spray chamber pressure on the spheroidization and oxidation phenomena was discussed. The results show that fewer Mo particles than W particles are spheroidized at the same powder feed rate under the same plasma spray condition although molybdenum has a lower melting point. A small fraction of tungsten is evaporized and condensed either on the surface of tungsten particles nearby or on the wall of spray chamber. Tungsten oxides were found in tungsten powder processed under soft vacuum condition. Extremely large grains form inside some spheroidized particles of tungsten powder.
基金This work was financially supported by the National Key Fundamental Research Program (973) G1998061316 and theYoung Researcher
文摘Several kinds of tungsten thermonic cathodes have been introduced. As a promising alternative for thoriated tungsten, rare earth doped molybdenum cathode has been studied. Compared with the traditional thoriated tungsten, La-Mo cathode has higher emission current density at lower temperature, but it has poor emission stability. In order to improve the emission stability, systematical study on the emission mechanism of La-Mo cathode has been carried out. The life of La-Mo cathode has been improved and has achieved 1400 It, which exceeds the minimum life for practical uses (1000 h). As another alternative for thoriated tungsten cathode, Y-Mo cathode has shown better performance. The thermionic emission capability of Y-Mo cathode is between that of La-Mo cathode and Th-W cathode.
文摘This article introduces a method determining the equation of penetration curve by multielement regression(MER) in study of double glow discharge plasma metallizing(DGM) and the slope of the penetration curve can be calculated by derivation,the xdy can also be obtained.This method is more reliable and accurate than graphical integration.The variation of diffusion coefficient with the concentration of W and Mo are determined.
文摘The interaction of nitrilotriacetic acid （NTA） and iminodiacetic acid （IDA） with tungsten（VI） （pH 7.5） and molybdenum（VI） （pH 6.00） has been studied in aqueous solutions at 25℃, and different ionic strengths （0.1 〈 1 （mol dm^-3） 〈 1.0 for NaClO4） by a combination of potentiometric and UV spectroscopic（260-270 nm） measurements. Dependence on ionic strength was taken into account by using the Bronsted-Guggenheim-Scatchard specific ion interaction theory （SIT） and parabolic model. The data included in this work, together with some previously published data, make it possible to calculate parameters for dependence on ionic strength by using the aforementioned models.
文摘Research on the separation of tungstenand molybdenum is of importance as it is a ba-sic problem in the metallurgy and industry oftungsten.Traditional methods for the separa-tion include precipitation with sulfides andsolvent extraction.There are,however,certaindisadvantages for these methods.A novelmethod was developed based on another
文摘The title complex was obtained by reactions of [Mo(CO)_3(MeCN)_3] with [CuBr(pySH)(PPh_3)_2]or directly with pySH and PPh_3. The latter method can be used to synthesize the corresponding tungsten complex [W_2(CO)_4(μ-pyS)_2(PPh_3)_2].The molecular structure of the title compound was determined by X-ray diffraction method.
基金supported by China Geological Survey(Nos.DD20230342,PMGR202108,DD20243431,and DD20190154)
文摘The Gaoaobei tungsten-molybdenum deposit is a newly discovered large-scale quartzvein-type deposit in the Nanling metallogenic belt in South China.The ore bodies are hosted in the Indosinian granites and the Cambrian Xiangnan Group slates and are controlled by NWW-oriented faults,which are obviously different from the“five-story building”model in southern Jiangxi Province.The magmatic rocks in the study area are dominated by medium-to coarse-grained biotite monzogranite,with a few NW-oriented fine-grained granite dykes.The medium-to coarse-grained biotite monzogranite and fine-grained granite dykes have zircon U-Pb ages of 229.4±1.9 Ma(MSWD=1.5)and 164.9±3.3 Ma(MSWD=0.75),respectively,corresponding to the Indosinian and Yanshanian magmatism.The monzogranites have higher contents of FeO,CaO,K2O,P2O5,and TiO2,while the granite dykes have slightly higher contents of SiO2,Al2O3,MnO,and Na2O.Their A/CNK values are 1.11-1.75 and 1.19-2.25,and the contents of CIPW normative corundum are 1.71%-6.66%and 2.41%-9.50%,suggesting both the monzogranites and granite dykes are S-type granite.The total amount of rare earth elements in the monzogranites(from 84.7 ppm to 129 ppm)is slightly lower than that in the granite dykes(from 128 ppm to 133 ppm).The Eu/Eu*values range from 0.12 to 0.30 in monzogranites and from 0.0011 to 0.0013 in granite dykes,indicating the fine-grained granites underwent more intense fractional crystallization.The monzogranite and granite dykes have high 87Sr/86Sri values of 0.7169-0.7193 and 0.72825-0.72880,lowεNd(t)values ranging from-10.2 to-9.6 and from-11.5 to-11.4,and TDM2 ages of 1835-1785 and 1957-1946 Ma,respectively.These isotope data indicate their origin from the remelting of the Paleoproterozoic crustal materials.Combined with regional geology,it is concluded that the medium-to coarse-grained biotite monzogranite was formed in a post-collisional extensional environment.In addition,40Ar-39Ar dating of the greisen type tungsten-molybdenum ore gave consistent plateau age of 164.0±1.2 Ma,isochronal age of 162.0±2.4 Ma and anti-isochronal age of 161.4±1.8 Ma.Combined with the published molybdenite Re-Os age,the Gaoaobei tungsten-molybdenum deposit was formed at~164 Ma,which is inferred to be genetically related to the contemporaneous finegrained granite dykes(165 Ma).The deposit was likely formed during the large-scale magmatism and mineralization event in the early Yanshanian of the Nanling Range in an intra-continental extensional environment caused by the subduction of the paleo-Pacific plate.The late and small granite dykes within the large granite plutons thus require further attention during mineral prospecting in the regions.
文摘试验采用高分辨率电感耦合等离子体质谱法(High-Resolution Inductively Coupled Plasma Mass Spectrometry,HR-ICP-MS)测定钨钼矿石中钨、钼、锂、铬、钴、镍、铜、锌、镓、锗、砷、硒、铷、铌、铟、锡、锑、铼、铊和铋等元素的含量。参考国家一级标准物质,对HR-ICP-MS进行数据比较和精确度验证,按照相关标准规定的方法确定HR-ICP-MS的检出限。结果表明,采用HR-ICP-MS测量钨钼矿石金属元素的相对标准偏差(Relative Standard Deviation,RSD)为0.86%~9.70%,各元素的检出限介于0.002~27.000 mg/kg,加标试验后的回收率损失小于2%,该方法可靠可信,准确度和精密度都能达到测试要求。
