Zr-Rich Eudialyte from the Lovozero Peralkaline Massif, Kola Peninsula, Russia

Panikorovskii, Taras L.; Mikhailova, Julia A.; Pakhomovsky, Yakov A.; Bazai, Ayya V.; Aksenov, Sergey M.; Kalashnikov, Andrey O.; Krivovichev, Sergey V.

doi:10.3390/min11090982

Cited by 3 publications

(1 citation statement)

References 41 publications

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“…Eudialyte is a unique mineral and nowadays is known as a potential source of rare earth and high-field-strength elements in the absence of radioactive elements such as uranium and thorium, which is the case for bastnasite, xenotime, monazite and steenstrupine. Significant resources of eudialyte and accompanied zirconosilicates are represented by Ilimaussaq and Tanbreez (Greenland), Norra Kärr (Sweden), Khibina and Lovozero (Russia), Mont Saint-Hilaire and Kipawa (Canada), Pilanesberg (South Africa), Saima (China) and Poços de Caldas (Brazil) [1,2]. Besides eudialyte and accompanied complex Zr and Ti silicates, the eudialyte ore consists of mafic minerals like amphiboles and pyroxenes and of alkali feldspars and feldspathoids like nepheline [3].…”

Section: Introductionmentioning

confidence: 99%

Prevention of Silica Gel Formation for Eudialyte Study Using New Digestion Reactor

Silin,

Dertmann,

Cvetković

et al. 2024

Minerals

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This work includes a combined hydrometallurgical treatment of a eudialyte ore sample with a subsequent preparation of leaching residue using mechanical separation methods. Hydrometallurgical treatment contains dry digestion with sulphuric acid at room temperature and filtration of the obtained product. The objectives of adopting these procedures are to test a new digestion reactor in order to prevent silica gel formation from the eudialyte ore. The obtained results revealed that silica gel formation is prevented during dissolution with sulphuric acid. A high leaching efficiency of light rare earth elements (La, Ce, Nd, Y) was reached using the dry digestion process with sulphuric acid, where the starting molarity was 12 mol/L. After the filtration process, magnetic separation is studied as the main method to recover weakly magnetic minerals like amphiboles and pyroxenes from the leaching residue in the magnetic fraction and feldspars in the nonmagnetic fraction. A new combined research strategy was developed for the production of different concentrates such as the one bearing Zr, Hf, and Nb.

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Section: Introductionmentioning

confidence: 99%

Prevention of Silica Gel Formation for Eudialyte Study Using New Digestion Reactor

Silin,

Dertmann,

Cvetković

et al. 2024

Minerals

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The Crystal Structure of Manganotychite, Na6Mn2(CO3)4(SO4), and Structural Relations in the Northupite Group

et al. 2023

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The crystal structure of manganotychite has been refined using the holotype specimen from the Alluaiv Mountain, Lovozero massif, Kola peninsula, Russia. The mineral is cubic, Fd3¯, a = 14.0015(3) Å, V = 2744.88(18) Å3, Z = 8, R1 = 0.020 for 388 independently observed reflections. Manganotychite is isotypic to tychite and ferrotychite. Its crystal structure is based upon a three-dimensional infinite framework formed by condensation of MnO6 octahedra and CO3 groups by sharing common O atoms. The sulfate groups and Na+ cations reside in the cavities of the octahedral-triangular metal-carbonate framework. In terms of symmetry and basic construction of the octahedral-triangular framework, the crystal structure of manganotychite is identical to that of northupite, Na3Mg(CO3)2Cl. The transition northupite → tychite can be described as a result of the multiatomic 2Cl− → (SO4)2− substitution, where both chlorine and sulfate ions are the extra-framework constituents. However, the positions occupied by sulfate groups and chlorine ions correspond to different octahedral cavities within the skeletons of Na atoms. The crystal structure of northupite can be considered as an interpenetration of two frameworks: anionic [Mg(CO3)2]2− octahedral-triangular framework and cationic [ClNa3]2− framework with the antipyrochlore topology. Both manganotychite and northupite structure types can be described as a modification of the crystal structure of diamond (or the dia net) via the following steps: (i) replacement of a vertex of the dia net by an M4 tetrahedron (no symmetry reduction); (ii) attachment of (CO3) triangles to the triangular faces of the M4 tetrahedra (accompanied by the Fd3¯m → Fd3¯ symmetry reduction); (iii) filling voids of the resulting framework by Na+ cations (no symmetry reduction); and (iv) filling voids of the Na skeleton by either sulfate groups (in tychite-type structures) or chlorine atoms (in northupite). As a result, the information-based structural complexity of manganotychite and northupite exceeds that of the dia net.

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Ion-Exchange-Induced Transformation and Mechanism of Cooperative Crystal Chemical Adaptation in Sitinakite: Theoretical and Experimental Study

et al. 2022

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The microporous titanosilicate sitinakite, KNa2Ti4(SiO4)2O5(OH)·4H2O, was first discovered in the Khibiny alkaline massif. This material is also known as IONSIV IE-911 and is considered as one of the most effective sorbents for Cs+ and Sr2+ from water solutions. We investigate a mechanism of cooperative crystal chemical adaptation caused by the incorporation of La3+ ions into sitinakite structure by the combination of theoretical (geometrical–topological analysis, Voronoi migration map calculation, structural complexity calculation) and empirical methods (PXRD, SCXRD, Raman spectroscopy, scanning electron microscopy). The natural crystals of sitinakite (a = 7.8159(2), c = 12.0167(3) Å) were kept in a 1M solution of La(NO3)3 for 24 h. The ordering of La3+ cations in the channels of the ion-exchanged form La3+Ti4(SiO4)2O5(OH)·4H2O (a = 11.0339(10), b = 11.0598(8), c = 11.8430(7) Å), results in the symmetry breaking according to the group–subgroup relation P42/mcm → Cmmm.

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Zr-Rich Eudialyte from the Lovozero Peralkaline Massif, Kola Peninsula, Russia

Cited by 3 publications

References 41 publications

Prevention of Silica Gel Formation for Eudialyte Study Using New Digestion Reactor

Prevention of Silica Gel Formation for Eudialyte Study Using New Digestion Reactor

The Crystal Structure of Manganotychite, Na6Mn2(CO3)4(SO4), and Structural Relations in the Northupite Group

Ion-Exchange-Induced Transformation and Mechanism of Cooperative Crystal Chemical Adaptation in Sitinakite: Theoretical and Experimental Study

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