Available hydrogen from formic acid decomposed by rare earth elements promoted Pd-Au/C catalysts at low temperature

ChemSusChem ◽  
2010 ◽  
Vol 3 (12) ◽  
pp. 1379-1382 ◽  
Author(s):  
Xiaochun Zhou ◽  
Yunjie Huang ◽  
Changpeng Liu ◽  
Jianhui Liao ◽  
Tianhong Lu ◽  
...  
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Rare Earth Elements ◽  
Formic Acid

scholarly journals EFFECTS OF THE LOW TEMPERATURE SEA-FLOOR WEATHERING ON THE RARE EARTH ELEMENTS OF THOLEIITIC BASALTS

1979 ◽  
Vol 18 (4) ◽  
pp. 385-394
Author(s):  
J. Urrutia Fucugauchi
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Rare Earth Elements ◽  
Baja California ◽  
Sea Floor ◽  
The Rare Earth

El presente trabajo se basa en resultados de elementos de tierras raras obtenidas en basaltos toleíticos provenientes de la boca del Golfo de California, México. Los basaltos fueron muestreados durante una operación de dragado en la latitud de 23° N.Los elementos de tierras raras fueron obtenidos por el método instrumental de activación por neutrones (López et al.. 1978). Las muestras fueron tomadas entre la cresta de la Dorsal de Pacífico Este y la plataforma continental de la península de Baja California. Las edades asignadas a las muestras con base en datos de anomalías magnéticas y de la relación batimetría edad del fondo oceánico son de 0, 1.7 y 3.5 millones de años. Los datos son empleados en este trabajo para evaluar el comportamiento de las tierras raras durante procesos de alteración a bajas temperaturas. Fue usado un procedimiento de normalización propuesto por Ludden y Thompson (1978) para datos de basaltos en la dorsal del Atlántico Medio (23°N). No obstante que el valor de la normalización (esto es, la abundancia de Yb para basaltos sin alteración) puede no ser válido para los basaltos de la Dorsal de Pacífico Este (23°N), los resultados obtenidos son consistentes y reflejan los efectos de alteración. Dichos resultados están de acuerdo con el modelo propuesto por Ludden y Thompson. Las muestras reflejan un enriquecimiento progresivo de las tierras raras ligeras (La a Sm) con la alteración (edad). Por otro lado, las diferencias observadas con respecto a los resultados anteriores indican que las tierras raras no se comportaran se igual forma en todos los ambientes de alteración. En particular, el elemento Ce muestra anomalías positivas y negativas. El agua de mar tiene una anomalía negativa, de aquí que este comportamiento puede ser interpretado en términos de la abundancia de Ce en el agua de mar o bien su fraccionamiento del agua de mar.

scholarly journals Allanite Geochemical Response to Hydrothermal Alteration by Alkaline, Low-Temperature Fluids

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 392 ◽  
Author(s):  
Katarzyna Gros ◽  
Ewa Słaby ◽  
Petras Jokubauskas ◽  
Jiří Sláma ◽  
Gabriela Kozub-Budzyń
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Rare Earth Elements ◽  
Geochemical Evolution ◽  
Additional Component ◽  
Second Stage ◽  
Ce Anomaly ◽  
Hydrothermal Processes ◽  
Fluid Infiltration ◽  
Two Stages

Allanite is one of the main rare earth elements (REE)-rich accessory minerals in composite dykes from the granitoid pluton of Karkonosze. These dykes differ in composition from the bulk of the pluton by elevated rare earth elements (REE), Y, Zr, and alkali contents, suggesting contribution of an additional component. Allanite exhibits complex alteration textures, which can be divided into two stages. The first stage is represented by allanite mantles, formed by fluid infiltration into previously crystallized magmatic allanite. These zones have low totals, are Ca-, Al-, Mg-, and light REE (LREE)-depleted, and Y-, heavy REE (HREE)-, Th-, Ti-, and alkali-enriched. The fractionation between LREE and HREE was caused by different mobility of complexes formed by these elements in aqueous fluids. The second stage includes recrystallized LREE-poor, Y-HREE-rich allanite with variable Ca, Al, Mg, and REE-fluorocarbonates. The alteration products from both stages demonstrate higher Fe3+/(Fe2+ + Fe3+) ratios and a negative Ce anomaly. These features point to the alkaline, low-temperature, and oxidized nature of the fluids. The differences in mobility and solubility of respective ligands show that the fluids from the first stage may have been dominated by Cl, whereas those of the second stage may have been dominated by F and CO2 (and PO4 in case of one sample). The inferred chemistry of the fluids resembles the overall geochemical signature of the composite dykes, indicating a major contribution of the hydrothermal processes to their geochemical evolution.

scholarly journals Low temperature NH3-SCR performance and mechanism of Mn and Fe supported CeCO3F-monazite catalysts

RSC Advances ◽  
2021 ◽  
Vol 11 (44) ◽  
pp. 27607-27619
Author(s):  
Na Li ◽  
Shenghan Zhang ◽  
Zedong Cheng ◽  
Wenfei Wu
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Rare Earth Elements ◽  
Excellent Performance ◽  
Nh3 Scr ◽  
Mineral Phases ◽  
Performance And Mechanism

The group has shown that Baiyun Ebo rare earth concentrate has excellent performance in NH3-SCR denitrification when used as a carrier, where rare earth elements are mainly present in cerium fluorocarbon ore (CeCO3F) and monazite (CePO4) mineral phases.

scholarly journals Genesis of the Xifeng Low-Temperature Geothermal Field, Guizhou, SW China: Constrains From Geology, Element Geochemistry, and D-O Isotopes

2021 ◽  
Vol 9 ◽  
Author(s):  
Yanyan Li ◽  
Ji Dor ◽  
Chengjiang Zhang ◽  
Guiling Wang ◽  
Baojian Zhang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Rare Earth Elements ◽  
Meteoric Water ◽  
Hot Springs ◽  
Geothermal Field ◽  
Frictional Heat ◽  
Geothermal System ◽  
Sw China ◽  
Deep Circulation

The Xifeng geothermal field is located in the Yangtze Craton, SW China, and is one of the most representative low-temperature geothermal fields in China. Widespread thermal anomalies, hot springs, and geothermal wells have been reported by previous studies. However, the nature and forming mechanisms of the field remain poorly understood. Element geochemical (ions, rare earth elements) and stable isotopic (D, O) composition of hot springs, geothermal fluids, rivers, and cold springs from different locations of the Xifeng geothermal field were analyzed in this study. The ions studies revealed that most samples featured the Ca-Mg-HCO3 type, except Xifeng hot springs, and which were characterized by the Ca-Mg-HCO3-SO4 type. Based on quartz geothermometers, the estimated reservoir temperature was 77°C. The results of stable isotopes (D, O) manifest that the Xifeng geothermal system was recharged by meteoric water at an elevation of 1,583 m from SW to NE. The research of rare earth elements (REE) revealed that their accumulation characteristics and obvious positive Eu anomaly were inherited from host feldspar-bearing reservoir dolomites through water-rock interactions. Combined with these observations, geological setting, and previous studies, it was concluded that the formation of the Xifeng geothermal field resulted from recharge, deep circulation, and secondary rising of the meteoric water along the faults. First, meteoric water infiltrated to depth through faults and crack zones. Second, the deep-infiltrated water was heated by radioactive heat, deep heat, and tectonic frictional heat. Finally, as the warmed-up waters underwent considerable deep circulation in the reservoir, it rose again along the main faults, and mixed with groundwater near the surface. Taken together, we suggest that the Xifeng geothermal system should be assigned as a faults-controlling, and deeply circulating meteoric water of low-temperature category.

Preparation and X-ray characterization of low-temperature phases of R2SiO5 (R = rare earth elements)

2001 ◽  
Vol 36 (10) ◽  
pp. 1855-1861 ◽  
Author(s):  
Jiaguo Wang ◽  
Shujian Tian ◽  
Guobao Li ◽  
Fuhui Liao ◽  
Xiping Jing
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Rare Earth Elements ◽  
X Ray
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