Apatite enrichment by rare earth elements: A review of the effects of surface properties

Owens, Camilla L.; Nash, George; Hadler, K.; Fitzpatrick, Robert; Anderson, Corby; Wall, Frances

doi:10.1016/j.cis.2019.01.004

Cited by 54 publications

(18 citation statements)

References 120 publications

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“…The EF of Sr correlates to apatite abundance and reflects the well documented substitution of Sr 2+ for Ca 2+ [47,57]. With the exception of Ce, the lanthanides, as well as Y, have a good correlation with apatite, due to the substitution of REE +3 in Ca 2+ and P 5+ sites in the apatite structure [47,[57][58][59]. The Ce anomaly [55] relatively to the average shale of both siliciclastics and phosphorites is less than unity, which implies that anoxic conditions were not prevalent.…”

Section: Trace Elementsmentioning

confidence: 99%

Significance and Distribution of Apatite in the Doig Phosphate Zone

Silva¹,

Bustin²

2020

Preprint

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The Doig Phosphate Zone (DPZ) is a phosphate-bearing marine unit located at the base of the Doig Formation, in the Triassic section of the Western Canada Sedimentary Basin. The DPZ has a maximum thickness of 90 m and extends across northeastern British Columbia and western central Alberta. In this study we characterize the significance and interpret the origin of apatite in the DPZ, through mineralogical and geochemical analyses, thin section study and field emission-scanning electron microscopy. The occurrence of apatite in the DPZ is not evenly distributed, but restricted to discrete 10 to 20 cm thick beds, located near the base of the DPZ. Phosphorites are of two types: grainstones composed primarily of unconformity-bounded coated grains, and intraclastic phosphorites composed of detrital silt-sized grains and apatite coated grains in a cryptocrystalline phosphatic matrix. The phosphorite beds are records of stratigraphic condensation due to low detrital input during transgression. The erosionally-truncated phosphatic coated grains and intraclasts are interpreted to be a result of various phases of phosphatization, exhumation, erosion reworking, winnowing and redeposition in alternating quiescence and storms or bottom currents. The abundance of pyrite and chalcophile trace elements, as well as the low concentration of proxy elements for organic matter productivity and preservation, are further evidences of stratigraphic condensation, with sulfidic pore water development and extensive organic recycling promoted by biological activity during the long exposure times. The phosphorites were formed under oxygenated water conditions, as suggested by the depletion in Ce and presence of a diverse benthic fauna.

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Section: Trace Elementsmentioning

confidence: 99%

Significance and Distribution of Apatite in the Doig Phosphate Zone

Silva¹,

Bustin²

2020

Preprint

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“…The EF of Sr correlates to apatite abundance and reflects the well-documented substitution of Sr 2+ for Ca 2+ [50,60]. With the exception of Ce, the lanthanides, as well as Y, have a strong to moderate positive correlation with apatite, due to the substitution of REE 3+ in Ca 2+ and P 5+ sites in the apatite structure [50,[60][61][62]. The Ce anomaly [58] relative to the average shale of both siliciclastics and phosphorites is less than unity, which implies that anoxic conditions were not prevalent.…”

Section: Trace Elementsmentioning

confidence: 99%

Significance and Distribution of Apatite in the Triassic Doig Phosphate Zone, Western Canada Sedimentary Basin

Silva

Bustin

2020

Minerals

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The Doig Phosphate Zone (DPZ) is a phosphate-bearing marine unit located at the base of the Doig Formation, in the Triassic section of the Western Canada Sedimentary Basin. The DPZ has a maximum thickness of 90 m and extends across northeastern British Columbia and west-central Alberta. In this study, we characterize the significance and interpret the origin of apatite in the DPZ through mineralogical and geochemical analyses, thin section study, and field emission scanning electron microscopy. The occurrence of apatite in the DPZ is not evenly distributed but restricted to discrete 10 to 20 cm thick beds, located near the base of the DPZ. Phosphorites are of two types: grainstones composed primarily of unconformity-bounded coated grains, and intraclastic phosphorites composed of detrital silt-sized grains and apatite coated grains in a cryptocrystalline phosphatic matrix. The phosphorite beds are records of stratigraphic condensation due to low detrital input during transgression. The erosionally truncated phosphatic coated grains and intraclasts are interpreted to be a result of various phases of phosphatization, exhumation, erosion, reworking, winnowing, and redeposition in alternating quiescence and storms or bottom currents. The abundance of pyrite and chalcophile trace elements, as well as the low concentration of proxy elements for organic matter productivity and preservation, are further evidence of stratigraphic condensation, with sulfidic pore water development and extensive organic recycling promoted by biological activity during the long exposure times. The phosphorites were formed under oxygenated water conditions, as suggested by the depletion in Ce and the presence of a diverse benthic fauna.

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“…In the flotation, OA often acted by combining with calcium atoms on the surface of fluorapatite to form calcium oleate [34][35][36][37]. In this chemical interaction process, the HOMO of OA as an electron donor loses electrons, while the LUMO of fluorapatite as an electron acceptor gets electrons.…”

Section: Effect Of Impurity On the Reactivity Of Fluorapatitementioning

confidence: 99%

“…On the other hand, apatite and its associated gangue minerals, such as dolomite and calcite, are usually separated by flotation [34][35][36][37]. The traditional collector for apatite flotation is fatty acids (such as oleic acid) and its salt [25,38,39].…”

Section: Introductionmentioning

confidence: 99%

“…The traditional collector for apatite flotation is fatty acids (such as oleic acid) and its salt [25,38,39]. In this process, the floatability of minerals depends on many properties, but most fundamentally on the surface properties, which have been studied and attempted by many researchers using different aspects, such as zeta potential and the isoelectric point [35]. Lattice defects of mineral have a great influence on their surface properties, which can change the lattice parameters of crystal, Fermi energy, electronic structure and frontier orbitals [29,33].…”

Section: Introductionmentioning

confidence: 99%

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A Theoretical Study on the Electronic Structure and Floatability of Rare Earth Elements (La, Ce, Nd and Y) Bearing Fluorapatite

et al. 2019

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Calcium atoms are often replaced by rare earth elements (REEs) in the lattice of fluorapatite (Ca10F2(PO4)6), making the phosphate ore an important potential rare earth resource. In this paper, the electronic properties of REEs (La, Ce, Nd and Y) bearing fluorapatite crystals have been investigated by density functional theory. Results of calculation indicated that the existence of REEs increased the cell parameters of fluorapatite in varying degrees. The REEs substitution made the Fermi level of fluorapatite to move to higher energy levels, making it easier to accept electrons. Except for Y, all the other REEs (La, Ce and Nd) showed that the electronic state mainly exists in the valence band. The Fermi level of REEs were mainly contributed by La5d, Ce4f, Nd4f and Y4d, respectively. The Mulliken values of REE–F and REE–O bonds in REEs-bearing fluorapatites were larger than those of Ca–F and Ca–O bonds in the perfect crystal, and the values of Y–F and Y–O bonds were the largest. The results of interaction between fluorapatite and oleic acid by frontier molecular orbital analysis suggested that the substitution of REEs can improve the reactivity of fluorapatite with oleic acid.

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Apatite enrichment by rare earth elements: A review of the effects of surface properties

Cited by 54 publications

References 120 publications

Significance and Distribution of Apatite in the Doig Phosphate Zone

Significance and Distribution of Apatite in the Doig Phosphate Zone

Significance and Distribution of Apatite in the Triassic Doig Phosphate Zone, Western Canada Sedimentary Basin

A Theoretical Study on the Electronic Structure and Floatability of Rare Earth Elements (La, Ce, Nd and Y) Bearing Fluorapatite

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