Modes of occurrences of scandium in Greek bauxite and bauxite residue

Vind, Johannes; Malfliet, Annelies; Bonomi, Chiara; Paiste, Päärn; Sajó, István E.; Blanpain, Bart; Tkaczyk, Alan H.; Vassiliadou, Vicky; Panias, Dimitrios

doi:10.1016/j.mineng.2018.04.025

Cited by 89 publications

(60 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It could analyze the elemental composition of particles with a diameter of 1 μm. And the WDS was used to accurately quantify the elemental composition of material [40][41][42]. The FE-EPMA-WDS results were shown in figure 3.…”

Section: Microstructurementioning

confidence: 99%

In situ decomposition of Ti₂AlN promoted interfacial bonding in ZnAl-Ti₂AlN biocomposites for bone repair

Shuai

Xue

Gao

et al. 2020

Mater. Res. Express

View full text Add to dashboard Cite

In this study, in situ decomposition of Ti 2 AlN was used to obtain strong interfacial bonding in Zn7Al-Ti 2 AlN composites prepared via laser melting. During the preparation process, the Al atoms in Ti 2 AlN could diffuse out of the lattice due to the weak bonding between Al and Ti, followed by easily diffusing into the liquid Zn7Al matrix. Consequently, the diffused Al could bond with the Al in Zn7Al matrix owing to their inherent chemical affinity, leading to a strong interfacial bonding in Zn7Al-Ti 2 AlN composites. This significantly improved the load transfer ability and prohibited the motion of dislocations in the composites. As a result, the hardness and compressive strength of Zn7Al-Ti 2 AlN composites were enhanced from 74 HV and 155 MPa to 80 HV and 205 MPa, respectively, which were more suitable for bone repair application. What's more, the composites also showed improved accelerated degradation and cytocompatibility.

show abstract

Section: Microstructurementioning

confidence: 99%

In situ decomposition of Ti₂AlN promoted interfacial bonding in ZnAl-Ti₂AlN biocomposites for bone repair

Shuai

Xue

Gao

et al. 2020

Mater. Res. Express

View full text Add to dashboard Cite

show abstract

“…The geochemical affinity of Sc with Fe 2 O 3 has been considered to a great extent both in bauxites and in laterites. Many authors [50][51][52] proposed that the Sc occurrence in residual soils is mainly related to an isomorphous substitution of Sc 3+ with Fe 3+ in the hematite lattice and lesser with the Sc 3+ uptaking as adsorbed metal onto the goethite surface. The behaviour of Ga during the bauxitization process could be variable.…”

Section: Genetic Processmentioning

confidence: 99%

Geochemical Characterization of Bauxite Deposits from the Abruzzi Mining District (Italy)

Putzolu¹,

Papa²,

Mondillo³

et al. 2018

Minerals

View full text Add to dashboard Cite

Abstract:The Abruzzi bauxite district includes the deposits located on the Campo Felice plateau and those of the Monti d'Ocre, which had been mined in the first part of the 20th century. Bauxite is of the karst type, with textures ranging between oolitic and oolitic-conglomeratic, the latter suggesting a partial reworking of evolved lateritic soils. The high contents of Al 2 O 3 and Fe 2 O 3 (average values 53.76 and 21.76 wt %, respectively) are associated with the presence of boehmite, hematite, and minor goethite. SiO 2 and TiO 2 have average values of 7.79 and 2.75 wt %, corresponding to the presence of kaolinite, anatase and rutile. Among the minor so-called "bauxitophile" elements V, Co, Ni, Cr and Zr, the most enriched is Cr, with an average value of 0.07 wt %. Nickel has an average value of 210.83 ppm. Vanadium shows an average value of 266.57 ppm, whereas the average Co concentration is 35.89 ppm. The total rare earth elements (REE) concentration in the sampled bauxite sites is variable between ca. 700 and 550 ppm. Among REEs, the most abundant element is Ce, with Ce anomalies commonly associated with authigenic REE-fluoro-carbonates, probably produced after the REEs remobilization from primary detrital minerals and their precipitation in neo-formed phases during the bauxitization process. Scandium and Ga occur in small amounts (57 and 60 ppm, respectively), but geochemical proxies of their remobilization and uptake in neo-formed minerals (Feand Al-(hydr)oxides, respectively) have been observed. The mean Eu/Eu* and Al 2 O 3 /TiO 2 ratios and the Ni-Cr contents of the Abruzzi bauxites suggest that the parent rock of these deposits was a material of acid affinity, likely corresponding to volcanic tephra or eolic loess-type sands.

show abstract

“…The fact that REEs and Sc are transferred to bauxite residue only in the composition of solid material is also supported by mineralogical studies [60,77]. One of the investigations has shown that the form of Sc occurrence mainly in the composition of hematite remains the same after bauxite processing [77]. On the other hand, the precursor REE phases found in bauxite are affected by the Bayer process conditions and REE ferrotitanate type compounds are created, but the transformations taking place seem to occur in situ on mineral grain surfaces without the dissolution of the precursor REE phases [60].…”

Section: Metals That Do Not Accumulate To Liquormentioning

confidence: 74%

“…None of the REEs or Sc enter into aluminium hydroxide, given the available detection limits, e.g., La < 0.5 mg/kg, Sm <0.1 mg/kg or Sc < 0.1 mg/kg (Supplementary Table S2). The fact that REEs and Sc are transferred to bauxite residue only in the composition of solid material is also supported by mineralogical studies [60,77]. One of the investigations has shown that the form of Sc occurrence mainly in the composition of hematite remains the same after bauxite processing [77].…”

Section: Metals That Do Not Accumulate To Liquormentioning

confidence: 82%

“…Enhanced concentrations of trace elements like Ni, Cr and V in the range of 700-4900 mg/kg were detected in perovskite-dominated matrix of a scale sample formed in the AoG's digestion autoclave. The cancrinite-dominated matrix of the same sample was, however, relatively depleted in trace elements (e.g., 140-170 mg/kg V) [77]. Sometimes, enhanced concentrations of V (112 mg/kg) and Ga (28 mg/kg) have been identified in the alumina dust from calciner electrostatic filters, making this material an attractive source of V and Ga [78].…”

Section: Metals (And Metalloids) That Accumulate To Liquormentioning

confidence: 92%

See 1 more Smart Citation

Distribution of Selected Trace Elements in the Bayer Process

Vind

Alexandri

Vassiliadou³

et al. 2018

Metals

Self Cite

View full text Add to dashboard Cite

Abstract:The aim of this work was to achieve an understanding of the distribution of selected bauxite trace elements (gallium (Ga), vanadium (V), arsenic (As), chromium (Cr), rare earth elements (REEs), scandium (Sc)) in the Bayer process. The assessment was designed as a case study in an alumina plant in operation to provide an overview of the trace elements behaviour in an actual industrial setup. A combination of analytical techniques was used, mainly inductively coupled plasma mass spectrometry and optical emission spectroscopy as well as instrumental neutron activation analysis. It was found that Ga, V and As as well as, to a minor extent, Cr are principally accumulated in Bayer process liquors. In addition, Ga is also fractionated to alumina at the end of the Bayer processing cycle. The rest of these elements pass to bauxite residue. REEs and Sc have the tendency to remain practically unaffected in the solid phases of the Bayer process and, therefore, at least 98% of their mass is transferred to bauxite residue. The interest in such a study originates from the fact that many of these trace constituents of bauxite ore could potentially become valuable by-products of the Bayer process; therefore, the understanding of their behaviour needs to be expanded. In fact, Ga and V are already by-products of the Bayer process, but their distribution patterns have not been provided in the existing open literature.

show abstract

Modes of occurrences of scandium in Greek bauxite and bauxite residue

Cited by 89 publications

References 42 publications

In situ decomposition of Ti₂AlN promoted interfacial bonding in ZnAl-Ti₂AlN biocomposites for bone repair

In situ decomposition of Ti₂AlN promoted interfacial bonding in ZnAl-Ti₂AlN biocomposites for bone repair

Geochemical Characterization of Bauxite Deposits from the Abruzzi Mining District (Italy)

Distribution of Selected Trace Elements in the Bayer Process

Contact Info

Product

Resources

About

Modes of occurrences of scandium in Greek bauxite and bauxite residue

Cited by 89 publications

References 42 publications

In situ decomposition of Ti2AlN promoted interfacial bonding in ZnAl-Ti2AlN biocomposites for bone repair

In situ decomposition of Ti2AlN promoted interfacial bonding in ZnAl-Ti2AlN biocomposites for bone repair

Geochemical Characterization of Bauxite Deposits from the Abruzzi Mining District (Italy)

Distribution of Selected Trace Elements in the Bayer Process

Contact Info

Product

Resources

About

In situ decomposition of Ti₂AlN promoted interfacial bonding in ZnAl-Ti₂AlN biocomposites for bone repair

In situ decomposition of Ti₂AlN promoted interfacial bonding in ZnAl-Ti₂AlN biocomposites for bone repair