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Characterization study of some bauxite deposits in northern Brazil

Barbara da Rocha Pereira, Morgana Rosset, Jose Diogo de Oliveira Lima, Keila Palheta Gomes, Denise Crocce Romano Espinosa and Jorge Alberto Soares Tenorio
Characterization study of some bauxite deposits in northern Brazil
Clays and Clay Minerals (December 2023) 71 (6): 707-721

Abstract

Alumina is produced from bauxite, which contains a mixture of various oxides, such as aluminum (Al), iron (Fe), silicon (Si), and titanium (Ti). Bauxite can also be considered a source of several other valuable metals, such as scandium (Sc), vanadium (V), and gallium (Ga). The composition and mineralogy of alumina determine their economic value, but their characteristics vary by locality. The physicochemical characteristics of bauxites can also be influenced largely by weathering processes, even within the same locality. For this reason, the present study was undertaken with the objective of comparing the characterization data of three bauxite samples collected, which will be referred to as D, E, and F, from the Cruz Alta do Para plateau in northern Brazil. The samples were solubilized by multi-acid digestion and fusion with lithium metaborate to quantify their metal compositions by inductively coupled plasma optical emission spectrometry (ICP-OES). The mineralogical characterization was conducted by X-ray diffraction (XRD), and the phase changes of minerals in bauxite were detected by thermogravimetric analysis (TGA/DTG). The total organic carbon (TOC) technique was used to quantify the C in the samples, and the moisture content was also measured. Alumina was 30 wt.% on average for all samples, good for producing high-purity alumina by hydrometallurgical processes. The results, however, showed high ( approximately 20 at.%) silica concentrations in two samples and approximately 3 wt.% Fe in one sample, which can pose a challenge in the Bayer process. The X-ray diffraction (XRD) analysis showed that gibbsite (Gbs), kaolinite (Kln), anatase (Ant), and hematite (Hem) were the major mineral phases in these samples. The study showed that the samples from the same mine vary in their metal content, especially with regard to Si, and they, thus, need to be processed selectively to maximize their economic value.


ISSN: 0009-8604
EISSN: 1552-8367
Coden: CLCMAB
Serial Title: Clays and Clay Minerals
Serial Volume: 71
Serial Issue: 6
Title: Characterization study of some bauxite deposits in northern Brazil
Affiliation: University of Sao Paulo, Laboratory of Recycling, Waste Treatment, and Extraction - Chemical Engineering, Sao Paulo, Brazil
Pages: 707-721
Published: 202312
Text Language: English
Publisher: Clay Minerals Society, Chantilly, VA, United States
Accession Number: 2024-043692
Categories: Economic geology, general, deposits
Document Type: Serial
Bibliographic Level: Analytic
Annotation: Based on Publisher-supplied data.
S34°00'00" - N05°15'00", W74°00'00" - W34°00'00"
Secondary Affiliation: Mineracao Rio do Norte, BRA, Brazil
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2024, American Geosciences Institute. Reference includes data supplied by Springer Verlag, Berlin, Federal Republic of Germany
Update Code: 2024
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