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See detailMineralogical and Chemical Characterizations of Natural Clays from NW Cameroon
Mache, Jacques Richard ULg; Fagel, Nathalie ULg; Njoya, André

Poster (2012, June)

In this study physical and chemical characterization of seven clay samples from Cameroon is reported. The various analysis show that the main clay mineral in all samples is smectite with a small amount of ... [more ▼]

In this study physical and chemical characterization of seven clay samples from Cameroon is reported. The various analysis show that the main clay mineral in all samples is smectite with a small amount of kaolinite; some non clay minerals as cristobalite, K-feldspars, plagioclase, ilmenite and quartz are also present. The Cation Exchange Capacities range from 24.2 to 62.0 meq/100g. The specific surface area range from 58 to 123 m2/g. The chemical composition of the clays is dominated by SiO2, Al2O3 and Fe2O3 whereas MgO and Na2O are present only in small quantities. [less ▲]

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See detailMineralogical and geotechnical characterization of clays from Northern Morocco for their potential use in ceramic industry
El Ouahabi, Meriam ULg; Daoudi, Lahcen; Fagel, Nathalie ULg

in Clay Minerals (2014), 49

This study focuses on the mineralogical and geotechnical characterization of Northern Morocco clays (i.e., from Tangier and Tetouan areas) and further comparison with main clay ores used in national ... [more ▼]

This study focuses on the mineralogical and geotechnical characterization of Northern Morocco clays (i.e., from Tangier and Tetouan areas) and further comparison with main clay ores used in national ceramic (i.e., from Meknes, Fes, Salé and Safi regions). Sampled clays were analyzed by X-ray diffraction on bulk and clay (< 2 µm) fractions to identify the mineralogical assemblages of the clay outcrops. Further analyses were conducted to determine the particle size distribution (laser diffraction particle analyser), the total organic matter content (from LossOnIgnition measurements) and the Atterberg limits of the raw clays. The aims of this study were first to investigate the spatial variability of the clay samples and second to evaluate their potential application as raw materials in ceramic industry. Tetouan and Tangier clays are characterized by diversified mineralogical assemblages (in particular a variable proportion of clay, quartz and calcite) in regard with Meknes, Fes, Salé and Safi clays (high clay content, quartz and calcite). The clay fraction of Tetouan and Tangier samples is dominated by illite and kaolinite with variable contribution of chlorite, smectite and/or vermiculite. Illite is the dominant phase in Meknes, Fes, Safi and Salé clays, but is associated with kaolinite. There is no direct relationship between the mineral assemblage composition and the lithology of the series. The studied clays materials consist generally in fine particles with medium to high plasticity and low organic matter content. Taking into account mineralogy, grain-size distribution and plasticity those clays seem to be suitable as raw material for the growing Morocco ceramic industry. [less ▲]

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See detailA mineralogical and microstructural study of 7 eucrites (A-881394, Y-791195, Y-981617, Y-790266, Y-791186, Y-792510, Y-793591)
Foucart, Hélène ULg; Holness, Marian; Namur, Olivier ULg et al

Conference (2012)

The mineral chemistry and the detailed microstructure of seven eucrites (A-881394, Y-791195, Y-981617, Y-790266, Y-791186, Y-792510 and Y-793591) of the NIPR collection of Antarctic meteorites have been ... [more ▼]

The mineral chemistry and the detailed microstructure of seven eucrites (A-881394, Y-791195, Y-981617, Y-790266, Y-791186, Y-792510 and Y-793591) of the NIPR collection of Antarctic meteorites have been examined in order to constrain their modal mineralogy and chemistry and to explore the potential of microstructural analysis as a new tool for interpreting meteorites. [less ▲]

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See detailMineralogical and Physical Changes during Sintering of Plastic Red Clays from Sanaga Swampy Valley, Cameroon.
Nzeukou, Aubin; Traina, K.; Mjedo, E.R. et al

in International ceramique review (2014), 63(4), 186-192

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See detailMineralogical characteristics of copper flotation products from Cayeli mine, Turkey and their influence to mineral processing
Strashimirov, S.; Dobrev, S.; Stamenov, S. et al

in Annual of the University of Mining and Geology, Sofia, 47, I, 147-153 (2004)

The paper presents mineralogical characteristics and pecularities of minerals distribution in products from Cu cycle of clastic ore mineral processing in Cayeli concentrator, Turkey. Special attention has ... [more ▼]

The paper presents mineralogical characteristics and pecularities of minerals distribution in products from Cu cycle of clastic ore mineral processing in Cayeli concentrator, Turkey. Special attention has been drawn to the mineralogical pecularities of sphalerite. The study has covered 16 samples from Cu flotation feed, Cu rougher concentrate, Cu final concentrate and tailing, each sieved in 4 granulometric classes. Significant quantity of sphalerite charactarized by higher amount of Cu and Fe as isomorphic impurities or extemely fine crystals of chalcopyrite are present in the Cu concentrate. Based on the performed studies, an improvement in the processing circuit has been suggested - especially in the grinding and hydrocycloning circuits. [less ▲]

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See detailMineralogical characterization of a gold ore through a computational mineral liberation analysis
Rojas, Ronald; Torem, Mauricio; Merma, Antonio et al

in Proceedings of the XV Balkan Mineral Processing Congress - BMPC 2013 (2013, June)

This work presents the mineralogical characterization of a very low-grade Brazilian gold ore. The aim is to provide mineralogical information and liberation distribution characteristics in order to assess ... [more ▼]

This work presents the mineralogical characterization of a very low-grade Brazilian gold ore. The aim is to provide mineralogical information and liberation distribution characteristics in order to assess a possible economic byproducts recovery. This may include a direct tailings processing or alternative gold processing routes. It was studied the distribution of all minerals present in the ore, mainly the gangue minerals. Distribution based on speciation, particle size, mineralogical association and liberation determined through the use of the automated analytical Scanning Electron Microscope technique (MLA). The study is complemented with chemical and mineralogical analysis by XRF and XRD respectively. It also includes particle size analysis, gravity separation and magnetic separation tests. Chemical analysis showed that the ore consists essentially of SiO2 (62.33%), Al2O3 (15.95%), Fe2O3 (7.66%), K2O (4.60%), TiO2 (1%) and others (8.46%). Based on this analysis, the study was mainly directed to the characterization of titanium-bearing minerals due to its economic importance. Therefore, minerals as ilmenite, rutile and anatase were identified as the Ti-bearing minerals. After a meticulous analysis of the results, it was identified a possible route for processing TiO2, taking into account the mineralogical and liberation point of view. [less ▲]

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See detailMineralogical gradients associated with alvinellids at deep-sea hydrothermal vents
Zbinden, M.; Le Bris, N.; Compère, Philippe ULg et al

in Deep-Sea Research Part I-Oceanographic Research Papers (2003), 50(2), 269-280

Alvinella pompejana and Alvinella caudata live in organic tubes on active sulphide chimney walls at deep-sea hydrothermal vents. These polychaete annelids are exposed to extreme thermal and chemical ... [more ▼]

Alvinella pompejana and Alvinella caudata live in organic tubes on active sulphide chimney walls at deep-sea hydrothermal vents. These polychaete annelids are exposed to extreme thermal and chemical gradients and to intense mineral precipitation. This work points out that mineral particles associated with Pompeii worm (A. pompejana and A. caudata) tubes constitute useful markers for evaluating the chemical characteristics of their micro-environment. The minerals associated with these worm tubes were analysed on samples recovered from an experimental alvinellid colony, at different locations in the vent fluid-seawater interface. Inhabited tubes from the most upper and lower parts of the colony were analysed by light and electron microscopies, X-ray microanalysis and X-ray diffraction. A change was observed from a Fe-Zn-S mineral assemblage to a Zn-S assemblage at the millimeter scale from the outer to the inner face of a tube. A similar gradient in proportions of minerals was observed at a decimeter scale from the lower to the upper part of the colony. The marcasitc/pyrite ratio of iron disulphides also displays a steep decrease along the few millimeters adjacent to the external tube surface. The occurrence of these gradients indicates that the microenvironment within the tube differs from that outside the tube, and suggests that the tube wall acts as an efficient barrier to the external environment. (C) 2003 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailMineralogical signatures of Lake Baikal sediments: Sources of sediment supplies through Late Quaternary
Fagel, Nathalie ULg; Thamo-Bozso, Edith; Heim, Birgit

in Sedimentary Geology (2007), 194(1-2), 37-59

The mineralogical composition of Late Quaternary sediments was investigated in three piston cores recovered on elevated plateaus in Lake Baikal: on Continent Ridge, a northern extension of Academician ... [more ▼]

The mineralogical composition of Late Quaternary sediments was investigated in three piston cores recovered on elevated plateaus in Lake Baikal: on Continent Ridge, a northern extension of Academician Ridge in the North Basin; on the Posolsky Bank near the Selenga Delta; and on the Vydrino Shoulder in the South Basin. The sediments are alternating biogenic diatom-rich muds and terrigenous silty clays, with sandy layers occurring in the southern (Vydrino) core. Core stratigraphy is based on AMS C-14 dates on pollen, diatom zonation, and magnetic record correlation: the 6-10 m long cores cover the last similar to 40 kyr in Vydrino, similar to 60 kyr in Posolsky and similar to 185 kyr in Continent Ridge. The bulk, clay (< 2 mu m) and sand (63-200 mu m) mineral signatures are compared with the mineralogical assemblages identified in river sediments and rocks sampled in the Selenga watershed and surface sediments collected in the various sub-basins. Spatial variability in the bulk mineral signature mainly reflects the sediment location relative to the lake margin. The complex clay mineral assemblages are more distinctive in terms of source-area. The clay signature of Vydrino core differs from the two other sites, in its high illite content. The Posolsky assemblage is consistent with the Selenga River clay mineral signature. The Continent Ridge clay assemblage is highly variable, reflecting mixing of several sources including a more proximal contribution than the Barguzin or even the Selenga tributaries. The similar homblende-dominated heavy mineral compositions of the Continent Ridge and Posolsky Bank sediments reflect the homogenous granitoid signature of the watersheds of the eastern side of Lake Baikal. In contrast, in the Southern Basin, the sediments from Vydrino Shoulder are mica-dominated, recording local sedimentary and metamorphic detritus supplies by numerous small rivers. Besides the control of sediment supply by the Selenga River, our data emphasize the significant influences of the Lake Baikal coastal margins in South and North Basin. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailMinéralogie de l’ancienne mine de plomb de La Roche-en-Ardenne (Belgique).
Blondieau, Michel; Hatert, Frédéric ULg

in Le règne minéral (2009), 88

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See detailMinéralogie de la carrière de Beez, Province de Namur, Belgique.
Blondieau, Michel; Hatert, Frédéric ULg; Defoy, Michel

in Règne minéral (Le) (2012), 104

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See detailMinéralogie et palynologie de croûtes et encroûtements calcaires de la steppe algérienne
Tsaki, H.; Mathieu, L.; Marcoen, Jean Marie ULg et al

in Biocénoses (1988), 3(1-2), 108-118

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See detailMinéralogie et pétrographie des phosphates de pegmatites brésiliennes, avec un intérêt particulier pour leurs relations avec les silicates
Baijot, Maxime ULg; Hatert, Frédéric ULg; Philippo, Simon

in Abstract book, 26ème Réunion annuelle des collaborateurs scientifiques du Musée d'histoire naturelle du Luxembourg (2009)

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See detailMinéralogie et propriétés physico-chimiques des smectites de Bana et Sabga (Cameroun). Utilisation dans la décoloration d'une huile végétale alimentaire
Mache, Jacques Richard ULg

Doctoral thesis (2013)

In this study, clay samples were collected in the localities of Bana and Sabga, in the regions of the west and north-west Cameroon, respectively. The purpose of this study was to determine their ... [more ▼]

In this study, clay samples were collected in the localities of Bana and Sabga, in the regions of the west and north-west Cameroon, respectively. The purpose of this study was to determine their mineralogical composition, their physico-chemical properties and to assess their potential use in the bleaching process of palm oil, which is the main edible vegetable oil produced and refined in Cameroon. <br /> The results obtained from the analyses (XRD, FTIR, DTA / TGA and SEM) revealed that montmorillonite is the main clay mineral in these materials. It is associated with kaolinite and mica. Non-clay minerals such as quartz, anatase, cristobalite, K-feldspar and heulandite are also identified in variable quantities. Chemical analyses of the major elements show that the clays from Bana and Sabga consist mainly of the follow oxides such as SiO2, Al2O3 and Fe2O3. Bana clays have a cation exchange capacity (CEC) between 50 and 60 meq/100 g and a specific surface area between 50 and 60 m2/ g. Sabga clays have a lower capacity cation exchange (38- 46 meq/100 g) and a wider range of specific surface area (33-90 m2 / g). The characterization of the natural clays allowed to select of one sample by locality for sulfuric acid treatment. <br />The acid treatment of these materials led to structural, morphological and textural changes. Analysis by X-ray diffraction showed a progressive decrease in the intensity of the (001) reflection of montmorillonite and a shift of its basal d001-value. Treatment with more acid concentration causes an increase in the surface area of the obtained products and a decrease in cation exchange capacity. <br />The assessment of the bleaching power of natural and acid-activated Bana clay in palm oil decolorization shows that the activated clay has a high bleaching capacity (~ 87%) compared to the natural clay (~ 55%). palm oil Bleaching by these clay materials does not deteriorate the bleached oil. These materials can thus be used as bleaching earths in the refining oil process. [less ▲]

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See detailMineralogy and petrography of phosphate minerals from pegmatites of the Conselheiro Pena district, Minas Gerais, Brazil
Baijot, Maxime ULg; Hatert, Frédéric ULg; Philippo, Simon

in Acta Mineralogica-Petrographica, Abstract series (2010), 6

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