The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
J Ruizfuertes - One of the best experts on this subject based on the ideXlab platform.
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a brief review of the effects of pressure on Wolframite type oxides
Crystals, 2018Co-Authors: Daniel Errandonea, J RuizfuertesAbstract:In this article, we review the advances that have been made on the understanding of the high-pressure (HP) structural, vibrational, and electronic properties of Wolframite-type oxides since the first works in the early 1990s. Mainly tungstates, which are the best known Wolframites, but also tantalates and niobates, with an isomorphic ambient-pressure Wolframite structure, have been included in this review. Apart from estimating the bulk moduli of all known Wolframites, the cation–oxygen bond distances and their change with pressure have been correlated with their compressibility. The composition variations of all Wolframites have been employed to understand their different structural phase transitions to post-Wolframite structures as a response to high pressure. The number of Raman modes and the changes in the band-gap energy have also been analyzed in the basis of these compositional differences. The reviewed results are relevant for both fundamental science and for the development of Wolframites as scintillating detectors. The possible next research avenues of Wolframites under compression have also been evaluated.
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high pressure phase transitions and compressibility of Wolframite type tungstates
Journal of Applied Physics, 2010Co-Authors: J Ruizfuertes, S Lopezmoreno, D Errandonea, J Pellicerporres, R Lacombaperales, A Segura, P Rodriguezhernandez, A Munoz, A H Romero, J A GonzalezAbstract:This paper reports an investigation on the phase diagram and compressibility of Wolframite-type tungstates by means of x-ray powder diffraction and absorption in a diamond-anvil cell and ab initio calculations. X-ray diffraction experiments show that monoclinic Wolframite-type MgWO4 suffers at least two phase transitions, the first one being to a triclinic polymorph with a structure similar to that of CuWO4 and FeMoO4-II. The onset of each transition is detected at 17.1 and 31 GPa. In ZnWO4 the onset of the monoclinic-triclinic transition has been also found at 16.7 GPa. This transition does not involve any change in the atomic coordination as confirmed by x-ray absorption measurements. These findings are supported by density-functional theory calculations, which predict the occurrence of additional transitions upon further compression. Calculations have been also performed for Wolframite-type MnWO4, which is found to have an antiferromagnetic configuration. In addition, our study reveals details of the l...
Jiehua Yang - One of the best experts on this subject based on the ideXlab platform.
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la icp ms upb geochronology of Wolframite by combining nist series and common lead bearing mtm as the primary reference material implications for metallogenesis of south china
Gondwana Research, 2020Co-Authors: Zhen Zheng, Yanwen Tang, Jiehua YangAbstract:Abstract Direct dating of W and W Sn deposits by Wolframite is more reliable relatively to gangue mineral and important for understanding their timing and genesis. However, such analysis still lacks of homogeneous Wolframite standard recently. Due to containing considerable and variable common lead, and inhomogeneous in different grains, the Wolframite sample of MTM, which is a promising candidate reference material proposed by previous studies, is not suitable as a primary standard for Wolframite U Pb dating by LA-ICP-MS using the normal normalization method as zircons. In this contribution, a modified normalization method is established for Wolframite U Pb dating, in which NIST612 or 614 and MTM are used for correction of Pb Pb and U Pb ratios, respectively. Wolframite U Pb dating are performed on the Langcun, Xihuashan, Piaotang, Shamai W or W Sn deposits and the Baiganhu ore district, the obtained lower intercept 206Pb/238U ages are comparable with the ages from syngenetic molybdenite, cassiterite, muscovite and the genetically related granites, as well as Wolframite by water vapor-assisted ns-LA-ICP-MS U Pb dating method. The results of this analysis demonstrate that the robust age for W mineralization can be determined by LA-ICP-MS U Pb dating of Wolframite using this modified calibration method. Mineralization ages of 125–130 Ma by directly dating of metal minerals for the Langcun W, Jianfengpo Sn and large-size Xianglushan W deposits confirm that there exists an important W Sn mineralization event in this period. The close temporal and spatial correlation indicates the granites and W-Cu-Mo-Pb-Zn-Sn mineralization have a genetic relationship with each other and are resulted from the same tectonic-magmatic-hydrothermal events during 140 to 120 Ma in South China.
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tracing the origin of ore forming fluids in the piaotang tungsten deposit south china constraints from in situ analyses of Wolframite and individual fluid inclusion
Ore Geology Reviews, 2019Co-Authors: Jiehua Yang, Lifang Kang, Jiantang Peng, Youqiang QiAbstract:Abstract The Piaotang vein-type tungsten deposit, hosted by Cambrian metasedimentary rocks, is one of the largest vein-type hydrothermal deposits in South China. Wolframite is the dominant ore mineral and intergrown with quartz and cassiterite in the main mineralization stage. Wolframite, cassiterite and quartz crystals have δ18O values ranging from 2.5 to 6.8‰, 6.1 to 7.2‰, 10.3 to 13.7‰, respectively. δD values of fluid inclusions in these minerals are very homogenous and lie mostly between −66.1 and −78.3‰. Chondrite-normalized REE patterns of Wolframite show HREE enrichment with significant negative Eu anomalies, which are different from those of hosting metasedimentary rocks. H-O isotopes of fluid inclusions and trace elements of Wolframite indicated that the ore-forming fluids in the Piaotang tungsten deposit are dominantly magmatic in origin. Metamorphic and meteoric fluids were not involved in the main mineralized stage although the Wolframite-quartz veins were hosted by metasedimentary rocks. Element pairs Zr/Hf and Y/Ho of Wolframite are remarkably fractionated (Zr/Hf = 13.4–34.6, Y/Ho = 10.0–14.4). Almost all the analyses of Wolframite display unusual tetrad effect REE patterns (TE1–3 > 1.1). These peculiar trace element characteristics of Wolframites indicate that ore-forming fluids have high ligands F and/or Cl contents. LA-ICP-MS analyses of individual fluid inclusion show that ore-forming fluids contain all elements necessary for the formation of Wolframite (W, Fe, Mn) and incompatible elements (e.g., Li, Rb, Cs). Cs/Na ratios are positively correlated with Rb/Na ratios. We conclude that the ore-forming fluids were reduced in nature and likely exsolved from the highly evolved granite that concealed in the vicinity of the deposit. Wolframite precipitation resulted from decreasing temperature and pressure of magmatic fluids during infilling along fracture, rather than fluid mixing and fluid-rock interaction.
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metal source and Wolframite precipitation process at the xihuashan tungsten deposit south china insights from mineralogy fluid inclusion and stable isotope
Ore Geology Reviews, 2019Co-Authors: Jiehua Yang, Jiantang Peng, Chengbiao LengAbstract:Abstract The Xihuashan tungsten deposit, hosted in the late Jurassic granitic pluton in the Nanling Range of South China, has a total resource of about 81,300 tonnes of WO 3 with an average ore grade of 1.08% WO 3 . Wolframite is the dominant ore mineral and intergrown with quartz in the main mineralization stage. Ore-forming fluids trapped in Wolframite have δD and δ 18 O values from -82‰ to -64‰ and 7.4‰ to 8.8‰, respectively. Those in quartz have similar δD (-72‰ to -58‰) and δ 18 O (6.8‰ to 8.0‰) values, indicative of a magmatic fluids simultaneously trapped by quartz and Wolframite. LA-ICP-MS analyses for individual fluid inclusion show that this mineralizing fluid contains measurable Li, Rb, Cs, K, Na, Ti, Cu, Zn, As and W (1 to 125 ppm with average of 19 ppm) while depleted in Fe and Mn. The Wolframite from the Xihuashan tungsten deposit contains high FeO (10.9 to 17.7 wt. %) and MnO (5.9 to 12.7 wt. %) contents with Fe/(Fe+Mn) atomic ratio of 0.46 to 0.75, thus requires the availability of external Fe and Mn. We detect that the Fe and Mn contents in mica from the greisen are remarkably lower than primary mica from granite. Some magmatic micas were observed in greisen and were subjected to hydrothermal alteration. Compared to the core, the rim of these micas depleted in Fe, Mn, F, and Na. The siderite and pyrophanite are formed along cleavage planes of altered magmatic mica that are evidence to be due to Fe and Mn release during granite alteration. Thus, we demonstrate quantitatively that magmatic fluids at Xihuashan provide W in solution, whereas the hosted granite alteration contributes Fe and Mn to precipitate Wolframite. It is also supported by Wolframites have trace and rare earth elements characteristics similar to those of granite and some characteristics similar to the greisen. Therefore, the ore-forming fluids has components derived from the last highly evolved residual granitic melt and components acquired by releasing through the hosted granite alteration. Fluid-rock interaction exert a principle control on Wolframite precipitation. Based on mineralogy, fluid inclusion and stable isotope, we proposed three-stage process to illustrate the genetical link between tungsten mineralization and granite.
Chengbiao Leng - One of the best experts on this subject based on the ideXlab platform.
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metal source and Wolframite precipitation process at the xihuashan tungsten deposit south china insights from mineralogy fluid inclusion and stable isotope
Ore Geology Reviews, 2019Co-Authors: Jiehua Yang, Jiantang Peng, Chengbiao LengAbstract:Abstract The Xihuashan tungsten deposit, hosted in the late Jurassic granitic pluton in the Nanling Range of South China, has a total resource of about 81,300 tonnes of WO 3 with an average ore grade of 1.08% WO 3 . Wolframite is the dominant ore mineral and intergrown with quartz in the main mineralization stage. Ore-forming fluids trapped in Wolframite have δD and δ 18 O values from -82‰ to -64‰ and 7.4‰ to 8.8‰, respectively. Those in quartz have similar δD (-72‰ to -58‰) and δ 18 O (6.8‰ to 8.0‰) values, indicative of a magmatic fluids simultaneously trapped by quartz and Wolframite. LA-ICP-MS analyses for individual fluid inclusion show that this mineralizing fluid contains measurable Li, Rb, Cs, K, Na, Ti, Cu, Zn, As and W (1 to 125 ppm with average of 19 ppm) while depleted in Fe and Mn. The Wolframite from the Xihuashan tungsten deposit contains high FeO (10.9 to 17.7 wt. %) and MnO (5.9 to 12.7 wt. %) contents with Fe/(Fe+Mn) atomic ratio of 0.46 to 0.75, thus requires the availability of external Fe and Mn. We detect that the Fe and Mn contents in mica from the greisen are remarkably lower than primary mica from granite. Some magmatic micas were observed in greisen and were subjected to hydrothermal alteration. Compared to the core, the rim of these micas depleted in Fe, Mn, F, and Na. The siderite and pyrophanite are formed along cleavage planes of altered magmatic mica that are evidence to be due to Fe and Mn release during granite alteration. Thus, we demonstrate quantitatively that magmatic fluids at Xihuashan provide W in solution, whereas the hosted granite alteration contributes Fe and Mn to precipitate Wolframite. It is also supported by Wolframites have trace and rare earth elements characteristics similar to those of granite and some characteristics similar to the greisen. Therefore, the ore-forming fluids has components derived from the last highly evolved residual granitic melt and components acquired by releasing through the hosted granite alteration. Fluid-rock interaction exert a principle control on Wolframite precipitation. Based on mineralogy, fluid inclusion and stable isotope, we proposed three-stage process to illustrate the genetical link between tungsten mineralization and granite.
Qiming Feng - One of the best experts on this subject based on the ideXlab platform.
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Beneficial effects and mechanism of lead ion on Wolframite flotation
Physicochemical Problems of Mineral Processing, 2020Co-Authors: Siyuan Yang, Ziyong Chang, Qiming Feng, Tiefeng Peng, Chuangang ZhongAbstract:In this study the effects and mechanism of lead ions influence on Wolframite flotation with benzohydroxamic acid (BHA) were studied through micro-flotation, adsorption experiments, zeta potential measurements, logarithmic concentration diagram, and X-ray photoelectron spectroscopy. It was observed that lead ions could significantly enhance the recovery of Wolframite in flotation and adsorption density of collector BHA onto the Wolframite surface. The results showed that Pb existed in the forms of lead ion, monohydric lead, and lead hydroxide at the water-Wolframite interface respectively, at three pH ranges. They increased the zeta potential of Wolframite. However, the zeta potential of Wolframite was still negative, resulting in repulsive electrostatic force to anionic collector BHA. Combining with XPS spectra, it revealed the chemisorption of BHA onto the Wolframite surface. In addition, PbO or Pb(OH)2 was observed on the Wolframite surface due to the reaction between lead ions and Wolframite. These reaction products increased the adsorption site of BHA on the Wolframite surface because Pb-hydroxamate was found on the Wolframite surface.
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effect of temperature on floatability and adsorption behavior of fine Wolframite with sodium oleate
Journal of Central South University, 2018Co-Authors: Qingyou Meng, Qiming Feng, Leming OuAbstract:The influence of pulp temperature on the floatability and adsorption behavior of fine Wolframite with sodium oleate was investigated by microflotation experiments, electric conductivity tests, adsorption measurements, and FT-IR analysis. Microflotation results show that fine Wolframite with sodium oleate exhibits a good floatability at pH 8–9. Electric conductivity tests indicate that the high temperature enhances the ionization degree and electric mobility of oleate species, then the flotation recovery of fine Wolframite and the adsorption amount of sodium oleate are observed to increase with the rise in pulp temperature. The results of adsorption experiments are found to meet Freundlich isotherms successfully, and the isosteric enthalpy (ΔHΘ) is in conformity with the chemical bonding. The changes in FT-IR analysis provide sufficient evidence that sodium oleate interacts with the metal cations of Wolframite surface, and the increase in pulp temperature clearly promotes the chemisorption intensity. These findings will be beneficial to strengthen the flotation behavior of fine Wolframite.
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the effect of quartz on the flotation of fine Wolframite with octyl hydroxamic acid
Minerals, 2017Co-Authors: Qingyou Meng, Qiming Feng, Zhitao Yuan, Leming OuAbstract:The influence of quartz on the flotation of fine Wolframite using octyl hydroxamic acid (OHA) as the collector was investigated by micro-flotation tests, inductively coupled plasma (ICP) measurements, adsorption experiments, zeta potential, and Fourier transform infrared spectroscopy (FT-IR) analysis. Micro-flotation tests showed that a large difference in floatability existed between fine Wolframite and quartz in the pH range of 7.0 to 10.0. However, in a synthetic mixture, the flotation separation of fine Wolframite from quartz became more difficult as the particle size of the latter decreased. When a dissolved solution of Wolframite was used as the flotation medium, quartz floatability improved significantly. Zeta potentials of quartz particles shifted positively in the dissolved solution of Wolframite compared to distilled water, especially at a pH level of 7.0–10.0, which was attributed to the metal ions dissolved from the Wolframite being adsorbed onto the quartz surface. The surface activation of quartz led to an increase in the OHA adsorption and made the surface hydrophobic. FT-IR analysis further demonstrated that OHA could adsorb onto the activated quartz surface through a dominantly chemical process.
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recovery enhancement of ultrafine Wolframite through hydrophobic flocs magnetic separation
Mineral Processing and Extractive Metallurgy Review, 2017Co-Authors: Qingyou Meng, Qiming Feng, Leming OuAbstract:ABSTRACTThe recovery of ultrafine Wolframite (<10 μm) by using flocs magnetic separation was investigated. Magnetic-separation results showed that recovery was closely correlated with the particle size of Wolframite, where ultrafine particles were difficult to capture. Hydrophobic particles induced by octyl hydroxamic acid (OHA) could generate flocs, which enlarged the apparent size of particles. Furthermore, the recovery of ultrafine Wolframite by flocs magnetic separation was higher than that by conventional magnetic separation. These findings indicated that the recovery was related to the increase in the magnetic force due to the particles’ size induced by hydrophobic flocculation.
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Recovery Enhancement of Ultrafine Wolframite through Hydrophobic Flocs Magnetic Separation
Mineral Processing and Extractive Metallurgy Review, 2017Co-Authors: Qingyou Meng, Qiming Feng, Leming OuAbstract:ABSTRACTThe recovery of ultrafine Wolframite (
Michel Cuney - One of the best experts on this subject based on the ideXlab platform.
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tracing metal sources in peribatholitic hydrothermal w deposits based on the chemical composition of Wolframite the example of the variscan french massif central
Chemical Geology, 2018Co-Authors: Matthieu Harlaux, Christian Marignac, Julien Mercadier, Chantal Peiffert, Christophe Cloquet, Michel CuneyAbstract:Abstract We present a complete dataset for major, minor and trace elements in Wolframite ([Fe,Mn]WO4) based on the example of several peribatholitic hydrothermal W deposits located in the Variscan French Massif Central (FMC). The Wolframite samples were characterized down to the micrometer scale by combining scanning electron microscopy observations and in situ chemical analysis by electron probe microanalyzer and laser ablation – inductively coupled plasma – mass spectrometry. Most samples are Fe-dominated Wolframites and are characterized by variable Fe/(Fe + Mn) values for the studied deposits (from 0.36 to 0.86) without significant alteration features. Wolframites present intracrystalline variations for concentrations of several minor and trace elements, principally for Nb, Ta, and Sn, which reflect growth zoning. The minor and trace element compositions of the different Wolframite samples show at first order similar enrichments in Ta, Nb, Sn, Zn, and In, as well as depletions in LREE, Li, Th, Ti, Zr, Hf, Pb, V, Co, and Mg, compared to the upper continental crust. Second order compositional variations are observed between the studied deposits, which can be separated in four main regional geochemical groups. This work highlights that the chemical composition of Wolframite is controlled by both the crystallochemical parameters and the composition of the primary hydrothermal fluid. The regional variations observed in the geochemical signatures of Wolframite reflect local variations in the composition of the hydrothermal fluid, i.e. variable metal sources. Therefore, this suggests that the minor and trace element contents in Wolframite likely represent direct markers of the source of the hydrothermal fluid and ultimately of the metals. The comparison between the trace element compositions of Wolframite with the compositions of regional granitic rocks and worldwide shales suggests that evolved peraluminous granites represent the main source of metals in peribatholitic hydrothermal W deposits from the FMC, whereas metasedimentary rocks have a limited to no influence on the metal budget.
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40 Ma of hydrothermal W mineralization during the Variscan orogenic evolution of the French Massif Central revealed by U-Pb dating of Wolframite
Mineralium Deposita, 2018Co-Authors: Matthieu Harlaux, Christophe Morlot, Christian Marignac, Julien Mercadier, Rolf L Romer, Michel CuneyAbstract:We present U-Pb thermal ionization mass spectrometer (TIMS) ages of Wolframite from several granite-related hydrothermal W±Sn deposits in the French Massif Central (FMC) located in the internal zone of the Variscan belt. The studied Wolframite samples are characterized by variable U and Pb contents (typically
