Natural and Synthetic Fluoride Carbonates

Grice, Joel D.; Maisonneuve, Vincent; Leblanc, M.

doi:10.1021/cr050062d

Cited by 44 publications

(48 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Authigenic bastnäsite and parisite group phases were further reported as representatives of authigenic fluorocarbonate LREE minerals in Parnassos-Ghiona bauxite (Pera Lakkos) [63]. As it is not clear on what basis was the distinction of parisite group from the rest of calcium-bearing REE phases made, we categorise it together with other calcium containing LREE fluorocarbonates, synchysite and röntgenite [64]. A recent report questions the earlier identifications of cerium-predominant REE phases, that they could be rather cerium oxides or carbonates, because of the absence of phosphorus and fluorine.…”

Section: Precursor Ree Phases In Aog's Bauxite Feedmentioning

confidence: 99%

Rare Earth Element Phases in Bauxite Residue

et al. 2018

View full text Add to dashboard Cite

Abstract:The purpose of present work was to provide mineralogical insight into the rare earth element (REE) phases in bauxite residue to improve REE recovering technologies. Experimental work was performed by electron probe microanalysis with energy dispersive as well as wavelength dispersive spectroscopy and transmission electron microscopy. REEs are found as discrete mineral particles in bauxite residue. Their sizes range from <1 µm to about 40 µm. In bauxite residue, the most abundant REE bearing phases are light REE (LREE) ferrotitanates that form a solid solution between the phases with major compositions (REE,Ca,Na)(Ti,Fe)O 3 and (Ca,Na)(Ti,Fe)O 3 . These are secondary phases formed during the Bayer process by an in-situ transformation of the precursor bauxite LREE phases. Compared to natural systems, the indicated solid solution resembles loparite-perovskite series. LREE particles often have a calcium ferrotitanate shell surrounding them that probably hinders their solubility. Minor amount of LREE carbonate and phosphate minerals as well as manganese-associated LREE phases are also present in bauxite residue. Heavy REEs occur in the same form as in bauxites, namely as yttrium phosphates. These results show that the Bayer process has an impact on the initial REE mineralogy contained in bauxite. Bauxite residue as well as selected bauxites are potentially good sources of REEs.

show abstract

Section: Precursor Ree Phases In Aog's Bauxite Feedmentioning

confidence: 99%

Rare Earth Element Phases in Bauxite Residue

et al. 2018

View full text Add to dashboard Cite

show abstract

“…All associations of the above minerals exist and were early recognized from morphological measurements. These features also explain the very long resistance of these minerals toward accurate structure determinations [45].…”

Section: Bastnaesitementioning

confidence: 91%

“…The addition of another anion, F − , can influence this topology. The development of a structural hierarchy of fluoride carbonates requires consideration of ratios of these two anions and their attached cationic polyhedral groups [45].…”

Section: Bastnaesitementioning

confidence: 99%

See 1 more Smart Citation

On the Origin of Bastnaesite-(La,Nd,Y) in the Nissi (Patitira) Bauxite Laterite Deposit, Lokris, Greece

et al. 2017

View full text Add to dashboard Cite

A detailed geochemical study and a thorough mineralogical description of the rare-earth elements (REE)-minerals and associated minerals were carried out in two vertical profiles of approximately 4 m length, from the Nissi (Patitira) bauxite laterite deposit, Lokris, Greece, characterized by the presence of goethite in small sizes resembling bacterial cell coated by goethite and a significant REE enrichment. The enrichment of the REE concentrated in bastnaesite-group minerals, the intergrowths between REE-minerals and Al-Ni-silicates with significant sulfur contents and their association with goethite microtextures interpreted as bacteriomorphic, indicate REE remobilization along with iron bio-leaching and re-precipitation on karstified limestone. In addition to the previous-reported hydroxylbastnaesites, a (La,Nd,Y)(CO 3 )F member of the bastnaesite-group associated with Al-Ni-silicates were identified, the stability of which may reflect the dependence on the source rocks and the local variations of pH-Eh. Interaction between downward percolating water and carbonate rocks seems to be a very effective mechanism for REE fluorocarbonates deposition under alkaline and reducing conditions.

show abstract

“…Hence, from the Equations (2) and (3) we can see that the NLO coefficient x (2) ijk is proportional to the density of the [CO 3 ] group (n/V) and the structural criterion (C). According to the notation of Grice et al [30], the [CO 3 ] groups in RbNa 5 Ca 5 (CO 3 ) 8 had two arrangements, flat-lying and standing-on-edge. The flat-lying [CO 3 ] groups in two successive [CaCO 3 ] ∞ layers present an opposite orientation, which give almost no contribution to the C factor.…”

Section: Relationship Between Structure and Nlo Propertiesmentioning

confidence: 99%