Rhabdophane-(Y), YPO&lt;sub&gt;4&lt;/sub&gt;&amp;middot;H&lt;sub&gt;2&lt;/sub&gt;O, a new mineral in alkali olivine basalt from Hinodematsu, Genkai-cho, Saga Prefecture, Japan

Takai, Yasuhiro; Uehara, Satoshi

doi:10.2465/jmps.111020j

Cited by 8 publications

(9 citation statements)

References 3 publications

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“…Aqueous REEs frequently become immobilized in phosphate minerals by the consumption of apatite or they are simply bound to aqueous P during alteration processes [27,64]. Under typical environmental conditions, the hydrated RE phosphates observed in the present study are expected to initially form at nanoscale sizes.…”

Section: Discussionmentioning

confidence: 87%

“…Organic matter, in particular, has the potential to control the stability of the rhabdophane structure, as some previous studies have reported that the rhabdophane structure was stable even for HREE (Yb, Lu) when organic matter was added to the starting reagent [60][61][62] or mechanical treatment was used to introduce it to the churchite structure [49,63]. A natural occurrence of rhabdophane-Y was reported by Takai and Uehara [64]; however, the mineral they discovered contains a wide variety of other LREE including~20 wt % La 2 O 3 and 15 wt % Nd 2 O 3 in addition to~15 wt % Y 2 O 3 . Thus, their report is consistent with the results obtained in the present experiments, which conclude that the structure is determined by the average ionic radius for phases that include multiple REEs.…”

Section: Discussionmentioning

confidence: 97%

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Crystal Chemistry and Stability of Hydrated Rare-Earth Phosphates Formed at Room Temperature

Ochiai

Utsunomiya

2017

Minerals

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Abstract:In order to understand the crystal chemical properties of hydrous rare-earth (RE) phosphates, REPO 4,hyd , that form at ambient temperature, we have synthesized REPO 4,hyd through the interaction of aqueous RE elements (REEs) with aqueous P at room temperature at pH < 6, where the precipitation of RE hydroxides does not occur, and performed rigorous solid characterization. The second experiment was designed identically except for using hydroxyapatite (HAP) crystals as the P source at pH constrained by the dissolved P. Hydrated RE phosphate that precipitated at pH 3 after 3 days was classified into three groups: LREPO 4,hyd (La → Gd) containing each REE from La-Gd, MREPO 4,hyd (Tb → Ho), and HREPO 4,hyd (Er → Lu). The latter two groups included increasing fractions of an amorphous component with increasing ionic radius, which was associated with non-coordinated water. RE all PO 4,hyd that contains all lanthanides except Pm transformed to rhabdophane structure over 30 days of aging. In the experiments using HAP, light REEs were preferentially distributed into nano-crystals, which can potentially constrain initial RE distributions in aqueous phase. Consequently, the mineralogical properties of hydrous RE phosphates forming at ambient temperature depend on the aging, the pH of the solution, and the average ionic radii of REE, similarly to the well-crystalline RE phosphates.

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Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 97%

Crystal Chemistry and Stability of Hydrated Rare-Earth Phosphates Formed at Room Temperature

Ochiai

Utsunomiya

2017

Minerals

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“…Most rhabdophane crystals in the Velence aplite dyke are euhedral hexagonal prisms which are rarely observed due to predominantly indistinguishable crystals forming massive and cryptocrystalline earthy aggregates, mammillary rounded forms, encrustations or pseudomorphs (cf. Hildebrand et al ., 1957; Fisher and Meyrowitz, 1962; Atkin et al ., 1983; Nagy and Draganits, 1999; Takai and Uehara, 2012; Matýsek, 2013). Chemically, they are typically Ce dominant, but in some La or Nd are dominant.…”

Section: Discussionmentioning

confidence: 99%

“…The REE phosphates of the rhabdophane group, including brockite, are documented from oxidized carbonatites (Andersen et al ., 2016). Moreover, rhabdophane-(Y) has been recorded in a druse in alkaline Higashimatsuura basalt in Japan (Takai and Uehara, 2012); and brockitic rhabdophane-(Ce) and rhabdophane-(La) occur in alkaline basalt (‘teschenite’) of the Silesian Unit, Czech Republic (Matýsek, 2013). Several occurrences of rhabdophane-group minerals and the closely related phase ningyoite have been reported in sedimentary uranium deposits of the Bohemian Cretaceous Basin, Czech Republic (Scharmová and Scharm, 1994).…”

Section: Introductionmentioning

confidence: 99%

Minerals of the rhabdophane group and the alunite supergroup in microgranite: products of low-temperature alteration in a highly acidic environment from the Velence Hills, Hungary

et al. 2018

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An assemblage of alunite-supergroup minerals (ASM), rhabdophane-group minerals (RGM), goethite and associated clay minerals occurs in Permian A-type porphyritic microgranite in the eastern part of the Velence Hills, Hungary. The secondary sulfates/phosphates include jarosite, Pb-rich jarosite and alunite, corkite, hinsdalite and rhabdophane-(Ce), -(La) and -(Nd). Detailed electron probe microanalysis and Raman spectroscopy reveal a wide miscibility among RGM end-members and show a rhabdophane–tristramite–brockite solid solution with extensive compositional variation. Moreover, ASM show heterogeneous composition and complex substitution mechanisms within the alunite, beudantite and plumbogummite groups. The formation of this rare mineral assemblage reveals extensive remobilization of rare-earth elements (REE), Th, U, P, S, Fe and Pb under supergene conditions. Compositional variations and substitution trends of the RGM investigated indicate that Th, U, Ca and Pb are incorporated into the rhabdophane structure by a (Ca, Pb)2+ + (Th, U)4+ ↔ 2REE3+ substitution mechanism. Consequently, we suggest the following end-member formulae for RGM containing divalent and tetravalent cations: (Ca0.5Th0.5)PO4·H2O for brockite, (Pb0.5Th0.5)PO4·H2O for grayite and (Ca0.5U0.5)PO4·2H2O for tristramite. The ASM and RGM originated from total leaching of the primary magmatic REE, Th, U and P minerals in the microgranite [most probably allanite-(Ce), fluorapatite and possibly also xenotime-(Y)], together with input of Pb and S in low-temperature, acid sulfate solutions, connected with an adjacent Palaeogene andesite–diorite intrusion and the accompanying hydrothermal sulfide mineralization.

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“…Based on the electron diffraction and compositional analysis, the phase was consistent with a rhabdophane type phase. Rhabdophane group minerals are hydrated phosphates (ideal formula is MPO 4 ⋅ nH 2 O), with M, in natural minerals, being light rare earth elements, Ca 2+ , Th 4+ , Pb, and U 4+ [25,26].…”

Section: Integral Ferric Iron Branching Edge Onset Fe-l 3 /L 2 Concenmentioning

confidence: 99%

Nature of nano-sized plutonium particles in soils at the Hanford Site

et al. 2014

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The occurrence of plutonium dioxide (PuO 2 ) either from direct deposition or from the precipitation of plutonium-bearing solutions in contaminated soils and sediments is well described, particularly for the Hanford site in Washington State. However, past research has suggested that plutonium at the Hanford site may exist in chemical forms in addition to PuO 2 . Although the majority of the plutonium is present as oxide, we present evidence for the formation of nano-sized mixed plutoniumiron phosphate hydroxide structurally related to the rhabdophane group minerals in 216-Z9 crib sediments from Hanford using both transmission electron microscopy (TEM) and X-ray absorption spectroscopy (XAS). The ironplutonium phosphate formation may depend on the local microenvironment in the sediments, availability of phosphate, and hence the distribution of these minerals may control long-term migration of plutonium in the soil.

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Rhabdophane-(Y), YPO<sub>4</sub>·H<sub>2</sub>O, a new mineral in alkali olivine basalt from Hinodematsu, Genkai-cho, Saga Prefecture, Japan

Cited by 8 publications

References 3 publications

Crystal Chemistry and Stability of Hydrated Rare-Earth Phosphates Formed at Room Temperature

Crystal Chemistry and Stability of Hydrated Rare-Earth Phosphates Formed at Room Temperature

Minerals of the rhabdophane group and the alunite supergroup in microgranite: products of low-temperature alteration in a highly acidic environment from the Velence Hills, Hungary

Nature of nano-sized plutonium particles in soils at the Hanford Site

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