Academic literature on the topic 'Clay minerals – Nigeria'

Studies of mineral distribution in soils provide vital information for understanding the genesis of the soil. We studied the soils formed on the floodplain of the River Niger to determine the occurrence, distribution, and weathering transformations of minerals in a soil chronosequence in eastern Nigeria. Five soil profiles representing 5 depositional stages were studied. The soils have aquic moisture regimes and an isohyperthermic temperature regime by Soil Taxonomy. Gleysation due to poor drainage is very dominant. The soils are low in pH, organic matter, and exchangeable cations. Plinthisation and ferralitisation resulting in high values of Fe2O3 and Al2O3 were observed in the coarse sand, while in the fine sand fractions, quartz and feldspar grains have accumulated with mica being next in abundance. The occurrence of expansible minerals and kaolinite in the clay fractions is as a result of transformation of mica and feldspars giving rise to these minerals. We postulate that the origin and abundance of K2O and MgO in the clay fractions were from the breakdown of the structural units of the expansible minerals, micas and feldspars. Illite undergoes a transformation process to expansible minerals, while kaolinitisation is the major process in the clay fractions. Principal component analysis shows that 23 mineral variables which relate with kaolinite and other silicate clays can be reduced to 5 principal components.

Three residual clay occurrences in Papalanto, Ifo, and Imoto areas which belong to the sedimentary basin of southwestern Nigeria were investigated to determine their industrial applications.The samples were pulverized, sieved, digested with mineral acids and characterized. Clay mineralogy was determined using X-ray Diffraction (XRD). Elemental compositions of the clay samples were determined using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Grain size distribution data were obtained by conducting grain size analysis in two parts; sieve analysis and sedimentation. Thermal properties, plasticity tests, density measurement, linear shrinkage and water absorption capacity were determined to evaluate their industrial potentials. Chemical Index of Alteration (CIA) was calculated to determine the degree of weathering in the area.The X-ray diffraction results showed that kaolinite is the dominant mineral, while quartz, anatase and hematite are the major non clay minerals. Chemical data showed that the average values of SiO2, Al2O3, and Fe2O3were 59.46%, 22.16%, and 3.06% respectively constituting 98.3% of the bulk compositions. Papalanto possessed high plasticity and mouldability.Evaluation of the clay thermal characteristics, firing colour, water absorption capacities and shrinkage values showed that the whitish Ifo clay and Papalanto kaolinitic clays could serve as raw materials for ceramics, building bricks, and other structural wares. Kaolin which is the dominant mineral in all the clays can be used for cosmetics, tooth paste, pharmaceutical purposes

<p class="zhengwen">Three residual clay occurrences in Idi-Ayunre, and Akure areas which belong to the Precambrian basement complex of southwestern Nigeria were investigated for their mineralogical, chemical and industrial properties. The investigation was to evaluate their industrial applications and economic importance. The clay within the weathered profiles above banded gneiss at Idi-Ayunre is whitish with red spots, whereas the clays derived from profiles above porphyritic granite and granite gneiss in Akure are grayish and brown in color respectively.</p><p class="zhengwen">The X-ray diffraction studies show that kaolinite is the dominant clay mineral, goethite, microcline, quartz, albite are the major non clay minerals in the samples. Chemical data showed that the average values of SiO₂, Al₂O₃, and Fe₂O₃ were 52.3. 30.29 and 3.54 wt% respectively constituting 86.13% of the bulk compositions.</p>Evaluation of the clay thermal characteristic, firing colour, water absorption capacities and shrinkage values show that the brownish Idi-Ayunre clay, gray and brown Akure kaolinitic clays could serve as raw materials for ceramics, building bricks, and other structural wares

Two residual clay deposits and one transported clay deposit in Ijesha-Ijebu area were investigated for their mineralogical, chemical and industrial properties. The investigation was to evaluate their industrial applications and economic importance. The mineralogy of the clay samples was determined using X-ray Diffraction (XRD). The chemical composition of the clay samples was determined using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Physical tests which include; thermal properties, plasticity tests, density measurement, linear shrinkage and water absorption capacity were determined to determine their industrial potentials. The clay within the weathered profiles above banded gneiss and pegmatite at Ijesha-Ijebu is brownish with red spots, while the clays derived from sedimentary terrain is chocolate in colour. The X-ray diffraction results showed that kaolinite is the dominant mineral, while quartz, albite and muscovite are the major non clay minerals. Chemical data showed that the values of SiO2, Al2O3 and Fe2O3 are 66.11%, 20.53% and 3.07%, respectively in weathered banded gneiss, in sedimentary the values of SiO2, Al2O3 and Fe2O3 are 42.12%, 34.43% and 7.37%. In weathered pegmatite, the values of SiO2, Al2O3 and Fe2O3 are 53.17%, 32.7%, 1.44%, respectively. The average percentage of clay in the banded gneiss, pegmatite and sedimentary samples are 50%, 56% and 47% respectively. The clay mouldability ranged between moderate to high. Evaluation of the clay properties and characteristics shows the industrial application of the clay like production of ceramic, building bricks and other structural wares. Keywords: Clay, Mineralogy, Chemistry, Ceramics, Building bricks.

This paper focuses on the need for domesticating the production of building materials like tiles to address the problem of Nigeria over dependence on imported goods, despite adequate availability of mineral resources like clay, quartz and feldspar in the country. Clay, quartz and feldspar, and milled glass were respectively obtained from Ogijo in Ogun State, Okpila in Edo State and Oshodi, Lagos State of Nigeria were characterized using ASTM C71 as a guide. Samples of the ceramic tile were produced from varying mixtures of clay, quartz, feldspar and milled glass. The chemical and physio mechanical properties of the samples were also determined. The results showed that the clay sample belong to Alumino-silicate group with 59.20% silica and 21.25% alumina. The samples’ properties met the required standards; hence, the materials were found suitable for production of ceramic tiles of acceptable standards. Though, the porosity of the sample tiles increased as thepercentage weight of the clay material in the mixture decreased the proportion of quartz, feldspar and milled glass increased. The sample containing 70% Clay and 30% Feldspar had better formulation properties than others.

Plasticity is an essential property of clay that determines its suitability for water filtration. There are no published works on the plastic behavior of clays from the study locations. The plastic behavior of seven Nigerian clays was examined using plasticity indices and compressive stress parameters in relation to chemical compositions and moisture content. The objective is to determine plastic behavior of some Nigerian clays and their suitability in production of Expanded Clay Aggregates (ECA) for water filters. Compressive stresses and deformation parameters were determined experimentally and compared theoretically. Atterberg limits (D 4318) were used to determine the plasticity indices. Chemical compositions of the samples were examined with XRF and correlated with plasticity and mineral contents of the clays. The clays are aluminosilicates with SiO2/Al2O3 ratio of 1.61 to 3.03 and plastic indices of 8 to 49. Low plastic indices (8–11) and low compressive stresses parameters were observed for kaolinite clays (0.002 MPa) due to their low affinity for water while zeolite rich clays showed high plastic indices (46 and 49) for Obowo and Minna and sharp difference in their compressive stresses parameters (0.15 and 0.03 MPa) at optimum moisture contents of 57% and 53%, respectively. Despite varying moisture content, chemical and mineral compositions, all curves showed similar trends apart from kaolinites at 40% moisture content. Relationships exist among microstructural properties, chemical composition, moisture content, compressive strength, and plasticity indices of the clays. The plastic behaviors show they are suitable for development of ECA for water filters.

Exploring for mineral deposits within the Anka Schist Belt involves the use of traditional geological techniques such as geochemical and geophysical studies that are very expensive and time consuming. There is therefore need for a better alternative that will provide accurate and reliable information with cost effective and time efficient solution. This effort seeks to explore the potential of remotely sensed digital data in highlighting mineralized zones through hydrothermal alteration studies. Landsat 8 OLI data covering the investigated area was used to detect and map locations of hydrothermal alterations. Image processing methods used were spectral enhancement, false colour composites, band rationing and Principal Component Analysis. Results of false colour composites of band 5: 7: 3 highlighted generally locations of hydrothermal alterations. Band ratios of 4/2, 6/7 and 6/5 revealed the presence of ferric iron minerals, clay rich minerals and ferrous minerals respectively. Principal Components (PCs) of two sets of images (2, 4, 5, 7 H-image and 2,5,6,7 F-image) depicting iron-oxide and hydroxyl mineral deposits as bright pixels were generated. Colour composite of H, F and H+F images enhanced the location of the mineral deposits, by showing areas of mineralization in dark blue (Fe rich), bright yellow (clay rich) and white (Fe and clay rich areas) pixels. Field coordinates of mining locations were superimposed on the remote sensing generated mineral map. The results were found to be in tune. This study recommends the use of remote sensing and geospatial technology in mineral studies through hydrothermal alteration within the basement complex rocks of Nigeria.

Clays are geological materials of economic potential in the manufacturing and environmental industries. Geotechnical properties and geochemical composition of Ifon clay deposits in Ondo State, Nigeria were investigated with the aim of determining their economic potentials. The geotechnical investigation includes consistency limits, strength, permeability and firing tests, while, X-ray fluorescence (XRF) method was used for determination of the bulk elemental composition of the clays using standard techniques. Geotechnical appraisal of the clay deposits revealed that high proportion of clay size fractions (52.3 – 66.1%) makes the clays suitable in their natural state for industrial raw materials. Activity of the clays was found to be low at approximately 0.3 – 0.7 and classified as inactive clays. Unconfined compressive strength varies between 3.4 N/mm2 and 4.7 N/mm2 and moderate shrinkage values (≤ 12%) indicate that the clays could be used as building construction materials. Coefficient of permeability of 7.75 × 10-8 to 1.72 × 10-5 cm/sec described the clays as low to impermeable soils suitable as barrier soils. SiO2 (64.41 – 68.74%) and Al2O3 (22.98 – 28.45%) contents dominate the clay geochemistry followed by iron oxide, Fe2O3 (3.57 – 8.31%) content among other oxides in traces, imply that they originated from underlying basement rocks subjected to varying degree of weathering. Low MgO, CaO, K2O and Na2O indicate no expandable clay minerals in the clays. The clays show low heavy metal concentrations which guarantee their suitability as raw materials in chemical industries. Thus, Ifon clay deposits are suitable for the production of ceramics, refractory bricks, paper, paints, rubber and fertilizer.

Clay generally refers to either fine grained earth material with particle size of less than two micron (< 2 m) or group of hydrous aluminum silicate minerals that are characterized by sheet silicate structure of composite layers stacked along the C-axis. They are common deposits found in most geological setting like in fine grained sedimentary rocks such as shale, mudstone, and siltstone, in fine grained metamorphic slate and phyllite. The interest in clay deposits arises from its numerous uses of the mineral group and the behaviour of soils constituents when used as engineering soil and its resultant effects on engineering structures like roads, dams, bridges and houses. Evaluation of the soil properties of the Chad Formation indicated that the plasticity characteristics of the samples are of low to medium plasticity as indicated by matching the result with the DIN. chart. The results of free swell showed that the samples are susceptible to swelling when they absorbed water. The particle size distribution tests indicate that the percentage of fine (i.e. samples passing the 75µm sieve) is about 1.7 % implying that the grain sizes are within the texture of medium grain fraction

X-ray diffraction is a basic tool in mineralogical analysis of sediments, and in the case of fine grained sediments an essential one. Understanding of rocks composition, the nature of clay mineralogy content and provenance is very important in Basin evaluation. This study therefore focuses on the use of X-ray diffraction to study the clay stone unit exposed along Igbile, southwestern Nigeria. Five clay stone samples were collected following fieldwork in the study area and were subjected to X-ray Diffraction analysis. This was done in order to delineate the associated mineral composition in the rock samples, determine the crystal forms and shape of the mineral and probably provenance of the mineral content. Observations from the result of the X-ray Diffraction indicated peaks with d-spacing range of 1.488Å, 1.63 Å, 1.59 Å, 1.62 Å and 7.17 Å indicative of Kaolinite and d-spacing range of 1.541Å, 1.817 Å, 2.282 Å, 2.458 Å, 3.343 Å and 4.26 Å indicative of quartz as the only significant, minor to moderate abundance minerals in the rock samples. The nature of the kaolinite in the rock samples is suggestive of a transformational and neoformational origin with acid tropical environment where the degree of leaching is probably intensive. The d-spacing and the plane axis values of the kaolinite also indicated Dioctahedral, Trioctahedral and Pinacoid crystal shape with range of forms {001},{060}, {133},{134}and {002}. Similarly the quartz d-spacing and plane axis values suggested Orthorhombic and Trigonal crystal shape with crystal forms {101}, {100}, {112}, {211}, {110}and {102}. In conclusion, the clay deposit exposed in the study area is made up of detrital kaolinite and quartz which are probably sourced from low latitude region in acid tropical high leaching environment.

Les gisements uranifères nigériens sont localisés dans les formations carbonifères et jurassiques du bassin de Tim Mersoï. AREVA est actionnaire de 3 sites miniers de cette région: la SOMAÏR et la COMINAK dans le district d'Arlit, en exploitation depuis 50ans, et IMOURAREN, 80km plus au Sud, dont l'exploitation est programmée pour 2015. La minéralisation du gisement d'Imouraren est comprise dans la formation fluviatile du Tchirézrine 2 (Jurassique), formée de chenaux et de plaines d'inondation. Les faciès de remplissage de chenaux vont des grès grossiers aux grès très fins (cortège détritique : quartz et feldspaths), tandis que les faciès de débordement sont constitués d'analcimolites. La minéralogie secondaire est acquise lors de 2 évènements : 1- la diagenèse, avec formation de minéraux argileux, d'analcime, de quartz et d'albite secondaires, et 2- un épisode de circulations de fluides, qui induit une altération des minéraux détritiques et diagénétiques, la formation de nouvelles phases et le dépôt de l'uranium. Cette altération dessine une zonation minéralogique à l'échelle du gisement.L'hétérogénéité du Tchirézrine 2, tant au niveau des faciès que de la minéralogie, se perçoit lors du traitement du minerai, puisqu'il réagit différemment selon sa provenance, avec parfois des problèmes de récupération de l'U. Des essais de traitement de minerais, ont montré que analcimes et chlorites étaient les deux pénalisants, pour 3 raisons : 1- les piégeages des phases U au sein des analcimes, 2- la dissolution de ces 2 minéraux a tendance à faire sortir des conditions de solubilisation de l'U (pH et Eh) et à former de nombreux sulfates, 3- problèmes de percolation. Une méthode de détection des minerais riches en analcimes, basée sur la spectroscopie infrarouge, a été développée afin d'optimiser les mélanges de minerais et ainsi de réduire les effets néfastes des pénalisants lors du traitement
Nigerian uraniferous deposits are located in carboniferous and jurassic formations of Tim Mersoï basin. AREVA is shareholder of 3 mine sites in this area: SOMAÏR and COMINAK, both in exploitation since 1960’s and IMOURAREN, 80km further South, whose exploitation is planned for 2015. Mineralization of Imouraren deposit is included in the fluvial formation of Tchirezrine 2 (Jurassic), composed of channels and flood plains. Facies of channel infillings range from coarse sandstones to siltstones, while overflow facies are composed of analcimolites.Secondary mineralogy was acquired during 2 stages: 1- diagenesis, with formation of clay minerals, analcime, secondary quartz and albites, and 2- stage of fluids circulations, which induced alteration of detrital and diagenetic minerals, formation of new phases and uranium deposition. A mineralogical zoning, at the scale of deposit resulted from this alteration. The heterogeneity of Tchirezrine 2, at the level of both facies and mineralogy, is also evidenced during ore treatment, as ore reacts differently depending on its source, with sometimes problems of U recovery. Ore treatment tests showed that analcimes and chlorites were both penalizing minerals, because of 1- the sequestration of U-bearing minerals into analcimes, 2- their dissolution which trends to move away from U solubilization conditions (pH and Eh) and to form numerous sulfates, and 3- problems of percolation. A detection method of analcime-rich ores, based on infrared spectroscopy, was developed in order to optimize ore blending and so to reduce negative effects during ore treatment process

PhDENV (Geology)
Department of Mining and Environmental Geology
The Cretaceous period marked the breaking up of Gondwana, giving rise to the separation of the African and South American continents with the subsequent emergence of the South Atlantic Ocean. Most correlation studies between the two continents with respect to paleoenvironmental conditions and tectonic settings during the Cretaceous- Tertiary periods have been concentrated more on the use of flora and fauna as indicators with less application of kaolinite as paleoenviromental proxies, hence, this study. The research involved the evaluation of paleoenvironmental conditions and tectonic settings of four (4) selected Cretaceous-Tertiary kaolin deposits with two (2) each from the Eastern Dahomey (Eruku and Lakiri) and Niger Delta (Awo-Omama and Ubulu-Uku) Basins in Nigeria. Representative kaolin samples collected from the selected deposits were analysed for physico-chemical, mineralogical, geochemical, isotopic, and geochronological data. The geochemical data obtained by x-ray fluorescence (XRF) spectroscopy and laser ablation inductively coupled plasma mass spectrometry (LAICPMS) were used in unraveling the provenance and tectonic settings of the kaolins. The kaolinite stable isotopic data for oxygen and hydrogen determined using a Finnigan Delta XP Mass Spectrometer were used to assess the paleoenvironmental and paleoclimatic conditions under which the kaolins were formed. The detrital zircon geochronological data acquired by laser ablation – single collector – magnetic sectorfield – inductively coupled plasma – mass spectrometry (LA-SFICP-MS) as well as kaolinite stable isotopic data were employed in constraining the probable timing of kaolinisation. The industrial applications of the kaolins were assessed based on the physico-chemical (Colour, particle size distribution (PSD), pH, electrical conductivity, and Atterberg limits), mineralogical, and geochemical data. The mineralogical data were obtained through x-ray diffractometry (XRD), Fourier transform infrared (FTIR) spectroscopy, Thermogravimetric analysis and differential scanning calorimetry, and scanning electron microscopy (SEM). Correlative studies between selected Cretaceous African and South American kaolins were conducted. The results showed that the dominant colour in the studied kaolins was pale red (39 %) followed by pinkish and light grey (35 %) as well as reddish yellow, light pink, light brown, vii reddish brown, and pinkish white. The pH and EC values generally ranged from 4.27 to 5.29 and 0.2 to 13.1 μS/cm, respectively. The kaolins predominantly have clay to sandy clay textures with plasticity indices between 10 and 22 wt %. Bulk mineralogical quantitative results indicated that the Cretaceous kaolins have kaolinite, quartz, and muscovite present in that decreasing order with anatase, goethite, and hematite in traces whereas Tertiary kaolins have kaolinite and quartz present in that decreasing order with anatase and goethite in traces. In the silt fractions, kaolinite and quartz were the dominant mineral constituents, whereas in the clay fractions, the dominant clay mineral was kaolinite accounting for 69 to 99 wt % with the non-clay minerals like quartz, anatase, hematite and goethite accounting for percentages between 1 to 28 wt % in the Cretaceous – Tertiary kaolins. Morphologically, the studied kaolins were characterised by pseudohexagonal stacks to books and thin platy kaolinite particles with moderate structural order. The chemical compositions of the Cretaceous-Tertiary kaolin deposits were identical to hydrated alumino-silicates based on the dominance of SiO2, Al2O3 and LOI. The chemical index of alteration (CIA) and chemical index of weathering (CIW) values varied between 96.98 to 99.39 % and 98.95 to 99.89 %, respectively. The clay fractions were enriched in Cr, Nb, Sc, Th, U, V, Zr, and LREE and depleted in Ba, Co, Rb, Sr, and HREE, respectively, relative to the average Upper Continental Crust (UCC). The Th/Sc, La/Sc, Th/Cr, and Eu/Eu* ratios were within the range of sediments derived from felsic rocks. The TiO2 versus Al2O3 and La-Th-Sc plots indicated source rocks with granitic – granodioritic - gabbroic compositions. Geochemical discrimination plots showed that the Cretaceous and Tertiary kaolins were deposited in passive margin tectonic settings. The stable isotopic results indicated that the values of the Cretaceous kaolins ranged from – 47 to – 57 ‰ and 19.1 to 19.8 ‰, respectively, with paleotemperatures between 29.0 and 32.2 ˚C, whereas the δD and δ18O corresponding values for the Tertiary kaolins ranged from – 54 to – 66 ‰ and 20 to 21.5 ‰, respectively, with paleotemperatures between 17.0 and 23.9 ˚C. viii The U-Pb dating of the detrital zircons showed that the Cretaceous - Tertiary kaolins have inputs from rocks of Eburnean (2500 – 2000 Ma) and Pan African (750 – 450 Ma) ages. The age of maximum deposition determined from the least to statistically robust approach corresponds to the Ediacaran Period (645 – 541 Ma) of the Neoproterozoic Era (1000 – 541 Ma). The Cretaceous – Tertiary kaolins were formed under intense anoxic chemical paleoweathering conditions of predominantly felsic rocks in addition to contributions from intermediate and mafic rocks in passive margin tectonic settings. The Cretaceous kaolins were formed under warmer conditions relative to the Tertiary kaolins. The West African Massif rocks were the main sediment sources for the Cretaceous kaolins, whereas both the West African and Northern Nigerian Massif rocks were the major sediment sources for the Tertiary kaolins. The most probable timing of kaolinisation for the Cretaceous – Tertiary kaolins occurred between the Ediacaran (645 – 541 Ma) and Early Cretaceous Periods for the Cretaceous kaolins and between the Ediacaran Period (645 – 541 Ma) and Oligo – Miocene age for the Tertiary kaolins. The Nigerian and Brazilian Cretaceous kaolins formed under similar warm tropical paleoclimate. The study corroborated the occurrence of the Eburnean (Transamazonian) and Pan African (Brasiliano) orogenic events across the African and South American continents. Beneficiation of the Cretaceous – Tertiary kaolins will allow large scale industrial applications in paper coating, ceramics, pharmaceutical, and cosmetics industries. The major contributions from this study have been: the better understanding of the past environmental conditions and tectonic settings, the dating of the possible timing of kaolinisation, and improvement on the potential industrial applications of the Cretaceous – Tertiary kaolins.
NRF