...Figure 12. Variation in parent-rock normalized light rare-earth elements with cerium anomaly/heavy rare-earth elements in specific state/parent rock indicated as (LREE-Ce)/HREE s/p ( a ) and whole-rock normalized cerium anomaly/heavy rare-earth elements in specific state/whole rock, (LREE-Ce...

...Yuanyuan Wang; Liu Liu; Mingqi Sun; Jian Huang; Yufeng Huang; Xiaoliang Liang; Wei Tan; Hongping He; Jianxi Zhu Abstract Ion adsorption-type rare earth deposits (IADs) are developed via prolonged weathering of REE-rich volcanic and metamorphic rocks. Intense magmatic activity which occurred during...

... transformation is ascribed to the drastic changes in the humid to arid climate, where former served as a source of Al and some of the Si and Mg ions for the later. Jhilmili and Anjar clays represent similar charge occupancies at different sites, but later contains relatively higher amount of palygorskite, formed...

... of corrugation than do Zr and Ti cations. The more open structures of neodymium and cerium silicates contain large channels that may serve as pathways for fast alkali ion transport. Copyright © 1997 by the Mineralogical Society of America 1997 ...

...John W. Adams Abstract Certain rare-earth elements, notably neodymium, praseodymium, erbium, and holmium, produce absorption bands in the visible region of the spectrum when present as trivalent ions in solutions or compounds In crystalline minerals these bands may be almost line-like and-have...

...Howard W. Jaffe; Howard T. Evans, Jr.; Randolph W. Chapman Abstract Chevkinite, a titano-silicate of the cerium earths, occurs as a well-crystallized accessory mineral in fayalite-quartz syenite of the Devil's Slide ring dike near Stark, New Hampshire. The mineral is monoclinic; space group C2/m...

... constituents (ash) of the coal. The extract contains, together with uranium, a concentration of several elements such as manganese, cerium, and vanadium that are present in the coal.Fischer assays of this weathered coal from the Red Desert indicate a yield of 16.7 gallons of tar per ton. Yields of both tar...

... 3 , Na 0.454 La 0.523 Ti 0.994 O 3 , Na 0.380 La 0.567 Ti 0.980 O 3 , and La 0.692 Ti 0.979 O 3 , respectively. The enthalpies of formation of cerium perovskites are −99.98 ± 5.78 and −45.78 ± 3.30 kJ/mol from oxides (Ce 2 O 3 , Na 2 O, TiO 2 ), and −1611.34 ± 6.90 and −1602.06 ± 2.72 kJ/mol from...

...% on the Ce/Y-Zr-MMT catalyst, additional peaks at 28.6, 33.1, 47.5 and 56.4°2θ were detected, indicating the formation of CeO 2 with a cubic fluorite structure. Hence, the diffraction profiles of the catalysts indicate that some of the cerium ions may be transferred into the interlayer of the Y-Zr-MMT...

...Xiangjie Cui; Huan Liu; Xiancai Lu; Juan Li; Jiani Chen; Ting-Shan Chan; Xiandong Liu; Rucheng Wang Abstract The ion-adsorption rare earth element (REE) deposit, a valuable type of REE deposit, has been thought to be derived from the release and enrichment of REE during granite weathering...

... and chevkinite is responsible for the enrichment of ΣLREE (Max.1645ppm) over ΣHREE (Max.129ppm) in Podili syenite evolved through volatile enriched Podili alkali granite. Enrichment of fluorocarbonate bastnaesite indicates the presence of halogen F- in the melt, which substitutes hydroxyl ion (OH...

... , G. , Gao , X. , Zhang , X. , & Song , S. ( 2017 ). Effect of cerium ions initial distribution on the crystalline structure and catalytic performance of CeY zeolite . Journal of Rare Earths , 35 , 791 – 799 . 10.1016/S1002-0721(17)60978-5 Zhang , J. , Li , X...

... and parent rock material had yet to completely break down. Results from X-ray fluorescence mapping, scanning electron microscopy (SEM), SEM-focussed ion beam milling (FIB-SEM), inductively-coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS highlight the migration pathways of REEs...

...) as is common in Paleozoic phosphate deposits. The nodules commonly preserve conspicuous europium anomalies that are not typical of phosphate deposits elsewhere in the geologic record, suggesting extremely reducing diagenetic conditions. Contrastingly, minor cerium anomalies imply oxidizing conditions...

... to Ce(III)-based solution has been demonstrated to accelerate the precipitation of a Ce-conversion coating layer (Hinton & Wilson, 1989). During the dipping, hydroxyl ions are generated from the reduction of H 2 O 2 at cathodic sites ( Ardelean et al ., 2001 ; Wang et al ., 2004 ): 5...

...Rui Wang; Yu Fu; Yayue Tang; Dengfeng Li; Xiaoming Sun; Gaowen He Cerium (Ce) anomalies in ferromanganese nodules serve as a crucial indicator of redox conditions during their formation, due to the differential solubility between Ce(III) and Ce(IV). Nodules of different origins always exhibit...

... for several bivalent metal ions and cerium(III) with the acetylacetonate ion . Journal of Physical Chemistry 59 : 235 - 237 Lehmann B Nakai S Höhndorf A Brinckmann J Dulski P Hein UF Masuda A ( 1994 ) REE mineralization at Gakara, Burundi: Evidence for anomalous...

... the existence of a mechanism of rare-earth metal accumulation different from the hydrogenic one and involving exchange reactions with Mn 4+ ions. Rare-earth phosphates associated with ferromanganese crusts, permanently exhibit a cerium minimum, which we called the cerium paradox. Fig. 22. Modified...

... of the increased productivity and to test the applicability of cerium anomalies as markers of redox-sensitive and/or indicators of paleoenvironmental or paleoceanographic conditions. The rare earth element (REE) data show typical seawater patterns and negative Ce/Ce* anomalies which appear to indicate...