نتایج جستجو برای: ree elements
تعداد نتایج: 278802 فیلتر نتایج به سال:
Marine microbialites serve as robust seawater rare earth element and yttrium (REE+Y) proxies through many intervals of Earth history, but questions remain about the partitioning of REEs into different coeval carbonate phases, potential syn-depositional contaminants and elemental redistribution during diagenesis. Microbial carbonates, cements and background sediments were analysed for stable iso...
The rare earth elements (REE) are increasingly important in a variety of science and economic fields, including (bio)geosciences, paleoecology, astrobiology, and mining. However, REE distribution in early rock-microbe-plant systems has remained elusive. We tested the hypothesis that REE mass-partitioning during incipient weathering of basalt, rhyolite, granite and schist depends on the activity...
The Kuh-e- Sefid and Banari phosphate horizons in Zagros Simply fold belt occurred in Pabdeh Formation. At this regard several samples collected from two phosphate horizons, for ICP-MS analyses. The result of ICP-MS analyses show that major oxides in two horizons are CaO> SiO2> Al2O3> Fe2O3> P2O5 respectively that the values of P2O5 in the Banari and Kuh-e- Sefid horizons is low and about 1.95 ...
We performed a series of experiments at high pressures and temperatures to determine the partitioning of a wide range of trace elements between ilmenite, armalcolite and anhydrous lunar silicate melt, to constrain geochemical models of the evolution of the interior of the Moon. Experiments yielding partition coefficients were performed in graphite-lined platinum capsules at pressures and temper...
The geochemistry of the suspended particulate matter (SPM) collected during the monsoon was determined to identify the sources of SPM and to understand the physicochemical processes in the Mandovi and Zuari river estuaries. The concentrations of SPM decrease seaward in both estuaries, but are relatively high at bay stations. Kaolinite is the most dominant clay mineral in the upstream of both ri...
Orthopyroxene (Opx) was present during a significant portion of crystallisation of the lunar magma ocean, but its influence on co-existing melt trace element contents is not well quantified. We performed high-pressure (P, 1.1 to 3.2 GPa), high-temperature (T, 1400 to 1600 °C) experiments on synthetic Fe-rich compositions at reducing conditions relevant to the lunar mantle to constrain trace ele...
Isotopic and elemental abundance signatures in the mass range Ba through Hf have been determined in a silicon carbide–rich sample of the Murchison carbonaceous chondrite, using inductively coupled plasma mass spectrometry (ICP-MS). Despite the problem of some isobaric interferences, useful results were obtained for a number of isotopes. Disagreements between astrophysical predictions and previo...
Fire clay of the Kabutarkuh deposit, located about 50 km southeast of Gonabad (Khorasan Province), was analyzed for its mineralogical and chemical compositions. Kaolinite, pyrophilite, quartz, dickite, gypsum, illite and alunite are the dominant minerals, and a minor phase of hematite is also present. Geochemical data show that the whole rock sample is mainly composed of SiO2, Al2O3 and K2O. Ch...
The demand for rare earth elements (REE) is increasing rapidly owing to the emergence of new clean-energy and defense-related technologies. China's dominates world production REE. In this paper, we review ore characteristics four typical REE deposits in China discuss conventional beneficiation techniques, including gravity magnetic separation, flotation, hydrometallurgical processing these ores...
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