Total of 23 bench samples were taken from the No. 7 Coal of Iqe Coalfield, Qinghai Province, China, following Chinese Standard Method GB/T 482-2008 (2008). These samples were analyzed by powder X-ray diffraction (...Total of 23 bench samples were taken from the No. 7 Coal of Iqe Coalfield, Qinghai Province, China, following Chinese Standard Method GB/T 482-2008 (2008). These samples were analyzed by powder X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP- MS) and X-ray fluorescence (XRF). The results indicate that the No. 7 Coal belongs to a low rank (Ro.ran =0.659%) and high-ash coal (40.54%). Compared to common Chinese and world low-rank coals, the lqe coal contains anomalous concentrations of rare metal elements, rare-scattered (dispersed) elements and rare earth elements. The highest contents of Rb, Cs, Ga and REY reach to 180, 26, 37, and 397 ppm, respectively. Their average contents of these elements are 10.9, 15, 4.8 and 3.5 times higher than those of world coals, respectively. Minerals in the coal include kaolinite, quartz, muscovite, siderite, and traces of rutile, and brookite. Kaolinite could be main host minerals of Rb, Cs, Ga and REY. The anomalous rare element Rb and Cs accumulation in the Iqe coal is related to both organic and inorganic matter. The REY concentrations may be related to circulation of thermal solutions, contained or sorbed by clayey particles, and organic matter as well.展开更多
The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can b...The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can be easily produced between these three elements in the filler metal, which greatly limited the formation of the isolated phase Pb or Bi and also eliminated the bad effect of impurity elements Pb and Bi on the spreading property of Ag-based filler metal. The metallurgical and quantum-mechanical bond formation analysis show that a strong chemical affinity was existed between the rare-earth element Ce and impurity elements Pb and Bi, which was proved by the XRD analysis results.展开更多
Ground water samples are collected from south West Bank/Palestine and analyzed for different rare elements (Rb, Zr, U, P, Ti, V), rare earth elements (La, Ce, and Nd), and other common trace metals (Li, Na, Mg, Ca, Sr...Ground water samples are collected from south West Bank/Palestine and analyzed for different rare elements (Rb, Zr, U, P, Ti, V), rare earth elements (La, Ce, and Nd), and other common trace metals (Li, Na, Mg, Ca, Sr, Ba, K, Bi) that most of them usually have no maximum acceptable limits as either they are considered not to be toxic to human health or there is no sufficient data about their toxicity to human health. This study was conducted to determine the water quality of ground water which is used for drinking in the study area. Water samples from ten groundwater wells were obtained in three different dates of the year (November 2012, March 2013, and April 2013). Three water samples were obtained from each well for each sampling date;so a total of 90 water samples were collected from the ten wells. The results obtained from this study suggest a possible risk to the population of the study area given the high concentration of some metals that have no maximum allowed concentration, and the fact that for many people in the study area, ground water is a main source of their water supply.展开更多
Cu46Zr47-xA17Mx (M = Ce, Pr, Tb, and Gd) bulk metallic glassy (BMG) alloys were prepared by copper-mold vacuum suction casting. The effects of rare-earth elements on the glass-forming ability (GFA), thermal stab...Cu46Zr47-xA17Mx (M = Ce, Pr, Tb, and Gd) bulk metallic glassy (BMG) alloys were prepared by copper-mold vacuum suction casting. The effects of rare-earth elements on the glass-forming ability (GFA), thermal stability, and mechanical properties of Cu46Zr47-xA17Mx were investigated. The GFA of Cu46Zr47-xA17Mx (M = Ce, Pr) alloys is dependent on the content of Ce and Pr, and the optimal content is 4 at.%. Cu46Zr47-xA17Thx(X = 2, 4, and 5) amorphous alloys with a diameter of 5 mm can be prepared. The GFA of Cu46Zr47-xA17Gdx(x = 2, 4, and 5) increases with increasing Gd. Tx and Tp of all decrease. Tg is dependent on the rare-earth element and its content. ATx for most of these alloys decreases except the Cu46Zra2Al7Gd5 alloy. The activation energies △Eg, △Ex, and △Ep for the Cu46Zr42A17Gd5 BMG alloy with Kissinger equations are 340.7, 211.3, and 211.3 kJ/mol, respectively. These values with Ozawa equations are 334.8, 210.3, and 210.3 kJ/mol, respec- tively. The Cu46Zr45Al7Tb2 alloy presents the highest microhardness, Hv 590, while the Cu46Zr43A17Pr4 alloy presents the least, Hv 479. The compressive strength (at.f.) of the Cu46Zra3A17Gd4 BMG alloy is higher than that of the Cu46Zr43Al7Tb4 BMG alloy.展开更多
Effect of rare earth elements (RE) on erosion resistance of nitrocarburized layer of 38CrMoAl steel was investigated. The results indicate that significant improvement occurs in erosion resistance of nitrocarburized 3...Effect of rare earth elements (RE) on erosion resistance of nitrocarburized layer of 38CrMoAl steel was investigated. The results indicate that significant improvement occurs in erosion resistance of nitrocarburized 38CrMoAl steel by introducing RE during nitrocarburizing processing as compared with conventional nitrocarburizing processing. Results of mechanical testing show that both hardness and impact toughness of RE-nitrocarburizing layer of 38CrMoAl steel increase as compared with the conventional one. Optical microscopy reveals that there is improvement in the nitrocarburized layer attributed to the introduction of RE, which results in improvement in erosion resistance. Surface morphology observation of tested samples reveals that predominantly furrow-like peelings from plastic deformation are observed for RE nitrocarburizied 38CrMoAl steel, while the furrow-like peeling with initial cross crack and large grinding peelings were observed for conventionally nitrocarburized samples.展开更多
This rain water samples harvested for drinking and agriculture from Gaza collected in November 2012 were analyzed for different rare metals (Rb, Zr, Ti, Tl, Sb, Sc, Y), and rare earth metals (La, and Ce). These metals...This rain water samples harvested for drinking and agriculture from Gaza collected in November 2012 were analyzed for different rare metals (Rb, Zr, Ti, Tl, Sb, Sc, Y), and rare earth metals (La, and Ce). These metals usually have no maximum acceptable limits as there is no sufficient data about their toxicity to human health. Their control should be therefore controlled in water to monitor their concentration in water (ground, harvested, etc.). This study was conducted to determine the water quality of harvested water which is used for drinking in the study area. 43 water samples were collected in November 2012 during the first rain from house wells and rain water pools. The concentrations of the metals detected in the collected harvested rainwater vary significantly between the 43 samples, and all of them were detected in all water samples analyzed in this study. The results obtained from this study suggest a possible risk to the population of the study area given the high concentration of some metals that have no maximum allowed concentration, and the fact that for many people in the study area, harvested rain water is a main source of their water supply.展开更多
The study was carried out to determine the rare metal mineralization potential of some pegmatites associated with metasediments in the Igangan 240 NW sheet. Geological mapping on a scale of 1:50,000 revealed the pegma...The study was carried out to determine the rare metal mineralization potential of some pegmatites associated with metasediments in the Igangan 240 NW sheet. Geological mapping on a scale of 1:50,000 revealed the pegmatites intrude metasediments and geochemical analysis for major, trace and rare earth elements were carried out using ICP MS/AES. Petrographic studies reveal a mineral assemblage of quartz, microcline and tourmaline;SEM studies revealed garnet and tourmaline to be close to the spessartine end-member and schorl respectively with albite occurring as the dominant plagioclase feldspar in the pegmatites. Result of geochemical analysis revealed SiO2 with an average of 73.91% in the whole rock pegmatite Al2O3 with an average of 13.93%, and average concentration of 0.57%, 4.3% and 4.77% for CaO, Na2O and K2O respectively. It also revealed average concentration of 29 ppm, 153 ppm, 30 ppm, 118 ppm and 129 ppm for W, Li, Ta, Nb and Sn in the mica respectively which is above the average values in the whole rock, felspars and tourmaline extracts. REE abundance in the whole rock pegmatites is low to moderate with ∑REE varying between 8 - 220 ppm, 2 - 23 ppm in feldspars and 3 - 32 ppm in mica signifying no form of REE enrichment. Geochemical analysis results and trace elemental plots such as K/Rb vs. Rb, Ta vs. Ga, Ta vs. Cs were used to assess rare metal mineralization and it revealed the pegmatites have low level of rare metal and rare earth element mineralization with average k/Rb values of 177 indicative of low fractionation levels in the pegmatites.展开更多
基金supported by the China geological survey project"Qaidam Basin Oil and Gas Resources Evaluation"(Nr:([2013]4-(3),001-008)National Natural Science Foundation of China(No.41330317)
文摘Total of 23 bench samples were taken from the No. 7 Coal of Iqe Coalfield, Qinghai Province, China, following Chinese Standard Method GB/T 482-2008 (2008). These samples were analyzed by powder X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP- MS) and X-ray fluorescence (XRF). The results indicate that the No. 7 Coal belongs to a low rank (Ro.ran =0.659%) and high-ash coal (40.54%). Compared to common Chinese and world low-rank coals, the lqe coal contains anomalous concentrations of rare metal elements, rare-scattered (dispersed) elements and rare earth elements. The highest contents of Rb, Cs, Ga and REY reach to 180, 26, 37, and 397 ppm, respectively. Their average contents of these elements are 10.9, 15, 4.8 and 3.5 times higher than those of world coals, respectively. Minerals in the coal include kaolinite, quartz, muscovite, siderite, and traces of rutile, and brookite. Kaolinite could be main host minerals of Rb, Cs, Ga and REY. The anomalous rare element Rb and Cs accumulation in the Iqe coal is related to both organic and inorganic matter. The REY concentrations may be related to circulation of thermal solutions, contained or sorbed by clayey particles, and organic matter as well.
文摘The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can be easily produced between these three elements in the filler metal, which greatly limited the formation of the isolated phase Pb or Bi and also eliminated the bad effect of impurity elements Pb and Bi on the spreading property of Ag-based filler metal. The metallurgical and quantum-mechanical bond formation analysis show that a strong chemical affinity was existed between the rare-earth element Ce and impurity elements Pb and Bi, which was proved by the XRD analysis results.
文摘Ground water samples are collected from south West Bank/Palestine and analyzed for different rare elements (Rb, Zr, U, P, Ti, V), rare earth elements (La, Ce, and Nd), and other common trace metals (Li, Na, Mg, Ca, Sr, Ba, K, Bi) that most of them usually have no maximum acceptable limits as either they are considered not to be toxic to human health or there is no sufficient data about their toxicity to human health. This study was conducted to determine the water quality of ground water which is used for drinking in the study area. Water samples from ten groundwater wells were obtained in three different dates of the year (November 2012, March 2013, and April 2013). Three water samples were obtained from each well for each sampling date;so a total of 90 water samples were collected from the ten wells. The results obtained from this study suggest a possible risk to the population of the study area given the high concentration of some metals that have no maximum allowed concentration, and the fact that for many people in the study area, ground water is a main source of their water supply.
文摘Cu46Zr47-xA17Mx (M = Ce, Pr, Tb, and Gd) bulk metallic glassy (BMG) alloys were prepared by copper-mold vacuum suction casting. The effects of rare-earth elements on the glass-forming ability (GFA), thermal stability, and mechanical properties of Cu46Zr47-xA17Mx were investigated. The GFA of Cu46Zr47-xA17Mx (M = Ce, Pr) alloys is dependent on the content of Ce and Pr, and the optimal content is 4 at.%. Cu46Zr47-xA17Thx(X = 2, 4, and 5) amorphous alloys with a diameter of 5 mm can be prepared. The GFA of Cu46Zr47-xA17Gdx(x = 2, 4, and 5) increases with increasing Gd. Tx and Tp of all decrease. Tg is dependent on the rare-earth element and its content. ATx for most of these alloys decreases except the Cu46Zra2Al7Gd5 alloy. The activation energies △Eg, △Ex, and △Ep for the Cu46Zr42A17Gd5 BMG alloy with Kissinger equations are 340.7, 211.3, and 211.3 kJ/mol, respectively. These values with Ozawa equations are 334.8, 210.3, and 210.3 kJ/mol, respec- tively. The Cu46Zr45Al7Tb2 alloy presents the highest microhardness, Hv 590, while the Cu46Zr43A17Pr4 alloy presents the least, Hv 479. The compressive strength (at.f.) of the Cu46Zra3A17Gd4 BMG alloy is higher than that of the Cu46Zr43Al7Tb4 BMG alloy.
文摘Effect of rare earth elements (RE) on erosion resistance of nitrocarburized layer of 38CrMoAl steel was investigated. The results indicate that significant improvement occurs in erosion resistance of nitrocarburized 38CrMoAl steel by introducing RE during nitrocarburizing processing as compared with conventional nitrocarburizing processing. Results of mechanical testing show that both hardness and impact toughness of RE-nitrocarburizing layer of 38CrMoAl steel increase as compared with the conventional one. Optical microscopy reveals that there is improvement in the nitrocarburized layer attributed to the introduction of RE, which results in improvement in erosion resistance. Surface morphology observation of tested samples reveals that predominantly furrow-like peelings from plastic deformation are observed for RE nitrocarburizied 38CrMoAl steel, while the furrow-like peeling with initial cross crack and large grinding peelings were observed for conventionally nitrocarburized samples.
文摘This rain water samples harvested for drinking and agriculture from Gaza collected in November 2012 were analyzed for different rare metals (Rb, Zr, Ti, Tl, Sb, Sc, Y), and rare earth metals (La, and Ce). These metals usually have no maximum acceptable limits as there is no sufficient data about their toxicity to human health. Their control should be therefore controlled in water to monitor their concentration in water (ground, harvested, etc.). This study was conducted to determine the water quality of harvested water which is used for drinking in the study area. 43 water samples were collected in November 2012 during the first rain from house wells and rain water pools. The concentrations of the metals detected in the collected harvested rainwater vary significantly between the 43 samples, and all of them were detected in all water samples analyzed in this study. The results obtained from this study suggest a possible risk to the population of the study area given the high concentration of some metals that have no maximum allowed concentration, and the fact that for many people in the study area, harvested rain water is a main source of their water supply.
文摘The study was carried out to determine the rare metal mineralization potential of some pegmatites associated with metasediments in the Igangan 240 NW sheet. Geological mapping on a scale of 1:50,000 revealed the pegmatites intrude metasediments and geochemical analysis for major, trace and rare earth elements were carried out using ICP MS/AES. Petrographic studies reveal a mineral assemblage of quartz, microcline and tourmaline;SEM studies revealed garnet and tourmaline to be close to the spessartine end-member and schorl respectively with albite occurring as the dominant plagioclase feldspar in the pegmatites. Result of geochemical analysis revealed SiO2 with an average of 73.91% in the whole rock pegmatite Al2O3 with an average of 13.93%, and average concentration of 0.57%, 4.3% and 4.77% for CaO, Na2O and K2O respectively. It also revealed average concentration of 29 ppm, 153 ppm, 30 ppm, 118 ppm and 129 ppm for W, Li, Ta, Nb and Sn in the mica respectively which is above the average values in the whole rock, felspars and tourmaline extracts. REE abundance in the whole rock pegmatites is low to moderate with ∑REE varying between 8 - 220 ppm, 2 - 23 ppm in feldspars and 3 - 32 ppm in mica signifying no form of REE enrichment. Geochemical analysis results and trace elemental plots such as K/Rb vs. Rb, Ta vs. Ga, Ta vs. Cs were used to assess rare metal mineralization and it revealed the pegmatites have low level of rare metal and rare earth element mineralization with average k/Rb values of 177 indicative of low fractionation levels in the pegmatites.