Minéralisations en Ta-Nb-W-Sn-Mo liées au magmatisme acide et à l'anatexie: Evolution chimique des magmas granitiques et caractéristiques des systèmes hydrothermaux associés

Report (1988)

Mineralogical and Chemical Characterizations of Natural Clays from NW Cameroon

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 ▲]

Mineralogical and geochemical study of pseudocoticules from the Stavelot Massif, Belgian Ardennes, and redefinition of coticule.

in Abstract Book (2012)

Mineralogical characteristics of copper flotation products from Cayeli mine, Turkey and their influence to mineral processing

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 ▲]

Mineralogical signatures of Lake Baikal sediments: Sources of sediment supplies through Late Quaternary

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 ▲]

Minéralogie de la carrière de Beez, Province de Namur, Belgique.

in Règne minéral (Le) (2012), 104

Minéralogie et propriétés physico-chimiques des smectites de Bana et Sabga (Cameroun). Utilisation dans la décoloration d'une huile végétale alimentaire

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 ▲]

Mineralogy and Nd and Pb isotope signatures of clay-size fraction of northern North Atlantic sediments during the Holocene and Late Glacial: Implications for the inception of modern deep circulation pattern

in Geochimica et Cosmochimica Acta (2007), 71(15), 265-265

Mineralogy and petrography of phosphate minerals from Sapucaia and Boca Rica pegmatites, Minas Gerais, Brazil

in Estudios Geologicos (2009), 19(2), 47-51

Minerals discovered in paleolithic black pigments by transmission electron microscopy and micro-X-ray absorption near-edge structure

in Applied Physics A : Materials Science & Processing (2006)