A new kaolin deposit in western Africa: mineralogical and compositional features of kaolinite from Caluquembe (Angola)

Large kaolin deposits developed by weathering on Precambrian granitic rocks have been discovered in the Caluquembe area, Huíla province, Angola. To determine accuracy of analysis and to evaluate the samples kaolinite grade, it was used full profile Rietveld refinement by X-­‐Ray Powder Diffraction (...

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Authors: Tauler, Esperança, Xu, Jingyao, Melgarejo, Joan Carles, Gonçalves, Antonio Olimpio, Campeny, Marc
Format: article
Publication Date:2019
Country:España
Institution:Ajuntament de Barcelona
Repository:BCNROC. Repositori Obert de Coneixement de l'Ajuntament de Barcelona
OAI Identifier:oai:bcnroc.ajuntament.barcelona.cat:11703/120655
Online Access:http://hdl.handle.net/2072/358307
https://doi.org/10.1007/s42860-019-00021-4
http://hdl.handle.net/11703/120655
Access Level:Open access
Keyword:Caolí
Terres rares
Ciència i tecnologia
articles
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spelling A new kaolin deposit in western Africa: mineralogical and compositional features of kaolinite from Caluquembe (Angola)Tauler, EsperançaXu, JingyaoMelgarejo, Joan CarlesGonçalves, Antonio OlimpioCampeny, MarcCaolíTerres raresCiència i tecnologiaarticlesLarge kaolin deposits developed by weathering on Precambrian granitic rocks have been discovered in the Caluquembe area, Huíla province, Angola. To determine accuracy of analysis and to evaluate the samples kaolinite grade, it was used full profile Rietveld refinement by X-­‐Ray Powder Diffraction (XRPD) and Gravimetric Thermal Analysis (TGA). Caluquembe kaolin is mainly comprised of kaolinite (44 to 93 wt.%), quartz (0 to 23 wt.%) and feldspar (4 to 14 wt. %). AGFI Crystallinity Index, calculated by XRPD profile refinement, indicates low and medium defect kaolinite. Kaolinite particles show a platy habit and they are stacked together forming ‘booklets’ or radial aggregates, also occurring as fine anhedral particles in a finer-­‐grained mass. Muscovite-­‐kaolinite intergrowths have also been found. Whole-­‐rock chemical composition was analyzed, including major, trace, and Rare Earth Elements (REE). Chondrite and Upper Continental Crust normalized REE patterns show the same tendency for all samples, with a significant enrichment in Light Rare Earth Elements (LREE). Mineralogical and compositional features of the Caluquembe kaolin indicate that it is a suitable material in the manufacture of structural products, such as bricks, pavers and roofing tiles. In addition, REE significant contents of the Caluquembe kaolin can be considered as a potential future target of mining exploration. Caluquembe; Angola; kaolinite; AGFI; REE.Consorci del Museu de Ciències Naturals de Barcelona202520252019info:eu-repo/semantics/articlehttp://hdl.handle.net/2072/358307https://doi.org/10.1007/s42860-019-00021-4http://hdl.handle.net/11703/120655reponame:BCNROC. Repositori Obert de Coneixement de l'Ajuntament de Barcelonainstname:Ajuntament de BarcelonaInglésinfo:eu-repo/semantics/openAccessoai:bcnroc.ajuntament.barcelona.cat:11703/1206552026-05-27T12:53:21Z
dc.title.none.fl_str_mv A new kaolin deposit in western Africa: mineralogical and compositional features of kaolinite from Caluquembe (Angola)
title A new kaolin deposit in western Africa: mineralogical and compositional features of kaolinite from Caluquembe (Angola)
spellingShingle A new kaolin deposit in western Africa: mineralogical and compositional features of kaolinite from Caluquembe (Angola)
Tauler, Esperança
Caolí
Terres rares
Ciència i tecnologia
articles
title_short A new kaolin deposit in western Africa: mineralogical and compositional features of kaolinite from Caluquembe (Angola)
title_full A new kaolin deposit in western Africa: mineralogical and compositional features of kaolinite from Caluquembe (Angola)
title_fullStr A new kaolin deposit in western Africa: mineralogical and compositional features of kaolinite from Caluquembe (Angola)
title_full_unstemmed A new kaolin deposit in western Africa: mineralogical and compositional features of kaolinite from Caluquembe (Angola)
title_sort A new kaolin deposit in western Africa: mineralogical and compositional features of kaolinite from Caluquembe (Angola)
dc.creator.none.fl_str_mv Tauler, Esperança
Xu, Jingyao
Melgarejo, Joan Carles
Gonçalves, Antonio Olimpio
Campeny, Marc
author Tauler, Esperança
author_facet Tauler, Esperança
Xu, Jingyao
Melgarejo, Joan Carles
Gonçalves, Antonio Olimpio
Campeny, Marc
author_role author
author2 Xu, Jingyao
Melgarejo, Joan Carles
Gonçalves, Antonio Olimpio
Campeny, Marc
author2_role author
author
author
author
dc.contributor.none.fl_str_mv Consorci del Museu de Ciències Naturals de Barcelona
dc.subject.none.fl_str_mv Caolí
Terres rares
Ciència i tecnologia
articles
topic Caolí
Terres rares
Ciència i tecnologia
articles
description Large kaolin deposits developed by weathering on Precambrian granitic rocks have been discovered in the Caluquembe area, Huíla province, Angola. To determine accuracy of analysis and to evaluate the samples kaolinite grade, it was used full profile Rietveld refinement by X-­‐Ray Powder Diffraction (XRPD) and Gravimetric Thermal Analysis (TGA). Caluquembe kaolin is mainly comprised of kaolinite (44 to 93 wt.%), quartz (0 to 23 wt.%) and feldspar (4 to 14 wt. %). AGFI Crystallinity Index, calculated by XRPD profile refinement, indicates low and medium defect kaolinite. Kaolinite particles show a platy habit and they are stacked together forming ‘booklets’ or radial aggregates, also occurring as fine anhedral particles in a finer-­‐grained mass. Muscovite-­‐kaolinite intergrowths have also been found. Whole-­‐rock chemical composition was analyzed, including major, trace, and Rare Earth Elements (REE). Chondrite and Upper Continental Crust normalized REE patterns show the same tendency for all samples, with a significant enrichment in Light Rare Earth Elements (LREE). Mineralogical and compositional features of the Caluquembe kaolin indicate that it is a suitable material in the manufacture of structural products, such as bricks, pavers and roofing tiles. In addition, REE significant contents of the Caluquembe kaolin can be considered as a potential future target of mining exploration. Caluquembe; Angola; kaolinite; AGFI; REE.
publishDate 2019
dc.date.none.fl_str_mv 2019
2025
2025
dc.type.none.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/2072/358307
https://doi.org/10.1007/s42860-019-00021-4
http://hdl.handle.net/11703/120655
url http://hdl.handle.net/2072/358307
https://doi.org/10.1007/s42860-019-00021-4
http://hdl.handle.net/11703/120655
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.source.none.fl_str_mv reponame:BCNROC. Repositori Obert de Coneixement de l'Ajuntament de Barcelona
instname:Ajuntament de Barcelona
instname_str Ajuntament de Barcelona
reponame_str BCNROC. Repositori Obert de Coneixement de l'Ajuntament de Barcelona
collection BCNROC. Repositori Obert de Coneixement de l'Ajuntament de Barcelona
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,812455

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