Ni-phyllosilicates (garnierites) from the Falcondo Ni-laterite deposit (Dominican Republic): Mineralogy, nanotextures, and formation mechanisms by HRTEM and AEM

Cristina Villanova-De-Benavent, Fernando Nieto, Cecilia Viti, Joaquín A. Proenza, Salvador Galí, Josep Roqué-Rosell

Research output: Contribution to journalArticle

Abstract

Ni-bearing magnesium phyllosilicates (garnierites) are significant Ni ores in Ni-laterites worldwide. The present paper reports a detailed TEM investigation of garnierites from the Falcondo Ni-laterite deposit (Dominican Republic). Different types of garnierites have been recognized, usually consisting of mixtures between serpentine and talc-like phases that display a wide range of textures at the nano-meter scale. In particular, chrysotile tubes, polygonal serpentine, and lizardite lamellae are intergrown with less crystalline, talc-like lamellae. Samples consisting uniquely of talc-like and of sepiolitefalcondoite were also observed, occurring as distinctive thin lamellae and long ribbon-shaped fibers, respectively. HRTEM imaging indicates that serpentine is replaced by the talc-like phase, whereas TEM-AEM data show preferential concentration of Ni in the talc-like phase. We suggest, therefore, that the crystallization of Ni-bearing phyllosilicates is associated with an increase in the silica activity of the system, promoting the replacement of the Ni-poor serpentine by the Ni-enriched talc-like phase. These results have interesting implications in material science, as garnierites are natural analogs of Ni-bearing phyllosilicate-supported synthetic catalysts. Finally, SAED and HRTEM suggest that the Ni-bearing talc-like phase corresponds to a variety of talc with extra water, showing larger d001 than talc (i.e., 9.2-9.7 Å), described as "kerolite"-"pimelite" in clay mineral literature.

Original languageEnglish
Pages (from-to)1460-1473
Number of pages14
JournalAmerican Mineralogist
Volume101
Issue number6
DOIs
Publication statusPublished - 1 Jun 2016

Fingerprint

Dominican Republic
laterites
Talc
talc
Mineralogy
laterite
phyllosilicate
mineralogy
formation mechanism
Deposits
deposits
Bearings (structural)
lamella
transmission electron microscopy
minerals
Serpentine Asbestos
lizardite
Transmission electron microscopy
natural analog
2-aminoethylmethacrylate

Keywords

  • "kerolite"-"pimelite"
  • chrysotile
  • garnierites
  • HRTEM
  • lizardite
  • Ni-laterites
  • polygonal serpentine
  • sepiolite-falcondoite

Cite this

Villanova-De-Benavent, Cristina ; Nieto, Fernando ; Viti, Cecilia ; Proenza, Joaquín A. ; Galí, Salvador ; Roqué-Rosell, Josep. / Ni-phyllosilicates (garnierites) from the Falcondo Ni-laterite deposit (Dominican Republic) : Mineralogy, nanotextures, and formation mechanisms by HRTEM and AEM. In: American Mineralogist. 2016 ; Vol. 101, No. 6. pp. 1460-1473.
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abstract = "Ni-bearing magnesium phyllosilicates (garnierites) are significant Ni ores in Ni-laterites worldwide. The present paper reports a detailed TEM investigation of garnierites from the Falcondo Ni-laterite deposit (Dominican Republic). Different types of garnierites have been recognized, usually consisting of mixtures between serpentine and talc-like phases that display a wide range of textures at the nano-meter scale. In particular, chrysotile tubes, polygonal serpentine, and lizardite lamellae are intergrown with less crystalline, talc-like lamellae. Samples consisting uniquely of talc-like and of sepiolitefalcondoite were also observed, occurring as distinctive thin lamellae and long ribbon-shaped fibers, respectively. HRTEM imaging indicates that serpentine is replaced by the talc-like phase, whereas TEM-AEM data show preferential concentration of Ni in the talc-like phase. We suggest, therefore, that the crystallization of Ni-bearing phyllosilicates is associated with an increase in the silica activity of the system, promoting the replacement of the Ni-poor serpentine by the Ni-enriched talc-like phase. These results have interesting implications in material science, as garnierites are natural analogs of Ni-bearing phyllosilicate-supported synthetic catalysts. Finally, SAED and HRTEM suggest that the Ni-bearing talc-like phase corresponds to a variety of talc with extra water, showing larger d001 than talc (i.e., 9.2-9.7 {\AA}), described as {"}kerolite{"}-{"}pimelite{"} in clay mineral literature.",
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Ni-phyllosilicates (garnierites) from the Falcondo Ni-laterite deposit (Dominican Republic) : Mineralogy, nanotextures, and formation mechanisms by HRTEM and AEM. / Villanova-De-Benavent, Cristina; Nieto, Fernando; Viti, Cecilia; Proenza, Joaquín A.; Galí, Salvador; Roqué-Rosell, Josep.

In: American Mineralogist, Vol. 101, No. 6, 01.06.2016, p. 1460-1473.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Ni-phyllosilicates (garnierites) from the Falcondo Ni-laterite deposit (Dominican Republic)

T2 - Mineralogy, nanotextures, and formation mechanisms by HRTEM and AEM

AU - Villanova-De-Benavent, Cristina

AU - Nieto, Fernando

AU - Viti, Cecilia

AU - Proenza, Joaquín A.

AU - Galí, Salvador

AU - Roqué-Rosell, Josep

PY - 2016/6/1

Y1 - 2016/6/1

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AB - Ni-bearing magnesium phyllosilicates (garnierites) are significant Ni ores in Ni-laterites worldwide. The present paper reports a detailed TEM investigation of garnierites from the Falcondo Ni-laterite deposit (Dominican Republic). Different types of garnierites have been recognized, usually consisting of mixtures between serpentine and talc-like phases that display a wide range of textures at the nano-meter scale. In particular, chrysotile tubes, polygonal serpentine, and lizardite lamellae are intergrown with less crystalline, talc-like lamellae. Samples consisting uniquely of talc-like and of sepiolitefalcondoite were also observed, occurring as distinctive thin lamellae and long ribbon-shaped fibers, respectively. HRTEM imaging indicates that serpentine is replaced by the talc-like phase, whereas TEM-AEM data show preferential concentration of Ni in the talc-like phase. We suggest, therefore, that the crystallization of Ni-bearing phyllosilicates is associated with an increase in the silica activity of the system, promoting the replacement of the Ni-poor serpentine by the Ni-enriched talc-like phase. These results have interesting implications in material science, as garnierites are natural analogs of Ni-bearing phyllosilicate-supported synthetic catalysts. Finally, SAED and HRTEM suggest that the Ni-bearing talc-like phase corresponds to a variety of talc with extra water, showing larger d001 than talc (i.e., 9.2-9.7 Å), described as "kerolite"-"pimelite" in clay mineral literature.

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