| dc.contributor.author | Xu, Jingyao | ca |
| dc.contributor.author | Amores, Sandra | ca |
| dc.contributor.author | Tauler, Esperança | ca |
| dc.contributor.author | Melgarejo, Joan Carles | ca |
| dc.contributor.author | Martínez, Salvador | ca |
| dc.contributor.author | Gonçalves, Antonio Olimpio | ca |
| dc.contributor.author | Campeny, Marc | ca |
| dc.contributor.other | Consorci del Museu de Ciències Naturals de Barcelona | ca |
| dc.date.accessioned | 2025-11-05T13:08:29Z | |
| dc.date.available | 2025-11-05T13:08:29Z | |
| dc.date.issued | 2017 | |
| dc.description | Kaolin deposits has been for long exploited in several regions of Angola, and some of the most important are
produced by weathering of anorthositic rocks from the Cunene complex. However, a systematic research has not
been carried out until the present moment. Some extensive outcrops of kaolinitic weathering proiles developed
on Precambrian granitic rocks were discovered during a recent trip in the Caluquembe area, in the Huila province
(SSE of Luanda).
The present study determined the mineralogical features and thermal properties of the clay minerals fromthese outcrops. The mineral composition was determined by means of X-ray diffraction, Raman spectroscopy and scanning
electron microscopy. The quantitative mineral phase analyses of the samples were obtained by X-ray diffraction
proile reinement using Topas V2.2. The thermal behaviour was studied by differential thermal and thermogravimetric analysis.
Whole-rock geochemical analyses on random powders (XRPD) reveal that samples are mainly composed of kaolinite, quartz, feldspars (e.g. albite and microcline) and muscovite. In addition, smectite and hematite have been
detected only in some samples. The obtained results indicate that samples present high kaolinite contents (~85
wt%), although a few samples which contain smectite have lower percentages of kaolinite (~28% wt%).
Thermal analyses were carried out to check the quantitative results of mineral phasesby XRPD. The differential
thermal analysis (DTA) curve showsonly an endothermic peak at about 540 °C in dry air which conirms the dehydration of kaolinite [1] in samples lacking smectite. Mass loss in the samples, measured by thermogravimetric
analysis (TG), is between 4 to 11 wt% until 650 ºC; samples with higher kaolinitecontents show the highest mass
loss values. The amount of kaolinite calculated by mass loss is between 90 and 25 wt%.
We can conclude that XRPD and TG results have a good correlation and the combination of both techniques is
suitable to determine the kaolinite content in this kind of clay deposits. Based on the high content of kaolinitefrom
the deposit of Caluquembe, this area is very suitable for the exploration and potential exploitation of kaolinite,
which is a very valuable raw material demanded in the fabrication of ceramics, cosmetics, paper or pharmaceutical
products. | |
| dc.format | application/pdf | ca |
| dc.format.extent | 1 p. | ca |
| dc.identifier | http://hdl.handle.net/2072/375898 | |
| dc.identifier.citation | XVI International Clay Conference (ICC 2017) (Granada, Spain) | ca |
| dc.identifier.entitat | consorcis | ca |
| dc.identifier.uri | http://hdl.handle.net/11703/120675 | |
| dc.language | eng | ca |
| dc.provenance | Recercat (Dipòsit de la Recerca de Catalunya) | ca |
| dc.rights | L'accés als continguts d'aquest document queda condicionat a l'acceptació de les condicions d'ús establertes per la següent llicència Creative Commons:http://creativecommons.org/licenses/by/4.0/ | |
| dc.rights | © Author(s) | |
| dc.rights.accessrights | info:eu-repo/semantics/openAccess | ca |
| dc.subject | Caolí | ca |
| dc.subject | Angola | ca |
| dc.subject | Raigs X | ca |
| dc.subject | Anàlisi tèrmica | ca |
| dc.subject.category | Ciència i tecnologia | ca |
| dc.subject.forma | conferències i ponències | ca |
| dc.title | Quantitative analysis and valorisation of Kaolinite from Caluquembe (Angola) by x-ray powder diffraction and thermogravimetric tecniques | |
| dc.type | info:eu-repo/semantics/conferenceObject | |
| dc.type.driver | info:eu-repo/semantics/conferenceObject | ca |
| metadadalocal.dependencia | 8008920 | |