Assessment of clay mineral deposits from Nkemkol in Ogoja local government area of cross river state for application as raw materials in ceramic industries

 Corresponding author: Paul Erungworo Okayim Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution License 4.0. Assessment of clay mineral deposits from Nkemkol in Ogoja local government area of cross river state for application as raw materials in ceramic industries Oru Ogar Njor 1, Gabriel Moshe Morod 1 and Paul Erungworo Okayim 2, * 1 Department of Chemistry, University of Cross River State, Nigeria. 2 Department of Physics, University of Calabar, Nigeria. World Journal of Advanced Research and Reviews, 2025, 27(03), 001-015 Publication history: Received on 11 June 2025; revised on 15 July 2025; accepted on 01 September 2025 Article DOI: https://doi.org/10.30574/wjarr.2025.27.3.2666 Abstract This research evaluated the potential of clay deposits from Nkemkol, Ogoja in Cross River State, Nigeria as local raw materials for industrial use. Four samples were gathered from various sites in the area. The clays were analyzed using X-ray fluorescence, X-ray and physical property tests to determine their geochemical composition, mineral content, and key characteristics. The analysis revealed high levels of silica (56.41%) and alumina (32.82%), which are typical of aluminosilicate clays. Iron oxide content was moderately high at 3.34% Fe2O3. The predominant clay minerals identified were kaolinite (18.9-37.0%) and illite (0.5-4.15%), along with non-clay minerals such as quartz, feldspars, and metal oxides. The clays exhibited significant plasticity (average plasticity index of 26.61%), facilitating easy molding and shaping. The average porosity was 21.33%, suitable for refractory applications. Firing shrinkage ranged from 6.5% to 19.2%, with density measurements between 1.54 and 1.76 g/cm³, both within acceptable limits. Post-firing strength met the minimum standard of 15 N/mm², with an estimated refractoriness of 1680.22°C. Overall, the Nkemkol clays possess favorable chemical, mineralogical, and physical properties for use in refractories and structural ceramics, pending some processing modifications. Utilizing these local deposits could enhance import substitution, foster rural industrialization, and support sustainable development in Nigeria. Further pilot testing is recommended to refine formulations and processes for specific ceramic products, along with a comprehensive national survey of clay deposits. The clays are deemed suitable for applications such as refractory bricks, ceramic tableware, architectural ceramics, wall tiles, and pottery items. Keywords: Clay mineral deposits; Ceramic industries; Cross River State; Geochemical composition; Aluminosilicate clays 1. Introduction Ceramics have played a vital role in human civilization for centuries, serving various purposes ranging from functional to decorative applications. Barsoum (2003) opined that the ceramic industry, which encompasses the production of a wide range of products such as bricks, tiles, pottery, sanitary ware, and advanced technical ceramics, is a significant contributor to the global economy. The success of this industry heavily depends on the availability and quality of clay resources, as clay is the primary raw material used in ceramic manufacturing. According to Guggenheim and Martin (1995), clay is a naturally occurring material composed primarily of hydrous aluminum silicates, along with other minerals and impurities. More specifically, it is mostly made up of hydrous aluminosilicate minerals that are organized in tightly packed layers or sheets using well-defined octahedral and tetrahedral geometry. According to Kerr (1952), if clay is composed of single units of alumina octahedral and silica tetrahedral, it is categorized structurally as (1:1); if clay is composed of two silica tetrahedral units, with an octahedral alumina unit sandwiched between the silica sheets, it is classified architecturally as (2:1). The unique properties of clay, including its plasticity, workability, and firing behavior, World Journal of Advanced Research and Reviews, 2025, 27(03), 001-015 2 make it an indispensable material in ceramic production. El Quahabi et al. (2014) studied the ceramic industry's potential for using clay raw materials from the northern Moroccan regions of Tetouan and Meknes. The authors noted that the Tetouan clays have medium to low SSA (specific surface area) and CEC (cation exchange capacity), according to the data, the clayey samples, SiO2 (35–54.3% wt), Al2O3 (20.6–43.9 % wt), and Fe2O3 (9.7–22.4% wt) were the principal oxides. Whereas CaO was exclusively found in some Tetouan clay, it ranges from 8.0 to 12.0% weight percent in Meknes clays. The authors also noted that the majority of Tetouan clays showed a notable densification of ceramic at fire temperatures exceeding 1000 °C, whereas Meknes clays shown this phenomenon starting at 800 °C. Consequently, the authors concluded that Tetouan and Meknes clays' chemical, textural, and ceramic qualities suggest that they are suitable for the creation of structural ceramics. Research on the characteristics of Cotrombian clay and its potential as an adsorbent was conducted by Macias-Quiroga et al. (2018). The authors pointed out that according to the chemical analysis, the main oxides are SiO2 (55.81% wt), Al2O3 (16.25 wt%), and Fe2O3 (7.51 wt%) and that the bulk clay's specific surface area, as determined by nitrogen adsorption, is 45.1 m2/g. They added that the potential of homogenized clay and organoclay for the removal of heavy metals in aqueous solutions was demonstrated by their achievement of Cr (III) and Cr (IV) removals greater than 85.05 ± 2.04% (pH between 3 and 4) and 82.93 ± 1.03 % (pH between 3 and 5), respectively. Aghayer and Kucukuysal (2018) investigated Usak clay's ceramic qualities in relation to Ukrainian clay. The results demonstrated that the samples differed, with quartz dominating USC (unifies soil classification) and kaolinite dominating UKC (unmodified kaolinite clay). Given that USC melts around 1300°C, it is unlikely that it can be categorised as refractory. This feature does, however, point to a potential financial benefit for USC in terms of creating technological traits at reduced temperatures. Akowanou et al. (2017) conducted a study to characterize clays from the "Se" region in the Southern part of Benin, which are utilized in the production of ceramic water filters. Three clay samples were obtained from a quarry in "Se", situated in the southwestern region of the Benin Republic. The samples underwent granulometric evaluation, X-ray Powder Diffraction (XRD), loss on ignition (LOI), cation exchange capacity (CEC), and measurement of Atterberg's limits for characterization. The clays' major elemental compositions were established. The chemical and mineralogical investigation reveals that all of the samples consist of different proportions of quartz and kaolinite, with muscovite and vermiculite being present as well. Additionally, they suggest that the clay components are composed of silico-aluminous clays. The CEC and N2 adsorption results indicate a low CEC and specific surface area, which is consistent with the existence of quartz and kaolinite quartz. The examined samples demonstrated that the clays possess a high degree of plasticity, with an organic matter concentration varying from 7.8% to 9.8% (as determined by loss on ignition). The TGA (thermogravimetric analysis) research indicated that the optimal sintering temperatures range from 700°C and higher. The authors noted that based on their mineral composition and physical properties, the clays are excellent as raw material for ceramic industries, notably for ceramic water filters. Abuh et al. (2018) explored the ceramics application of Mgbom clay: characterisation and micro-structural research. The physical, chemical and spectral characterization of the clay was carried out. It was revealed that band corresponding with quartz, carbonates and kaolinite were observed. The x-ray examination revealed the existence of quartz (SiO2). Kaolinite (Al2Si2O5 with hematite (Fe2O3). The physical characterization also indicated values of modulus of plasticity (1.23) and water of plasticity (46%) which characterises the clay as strong, plastic and expansive. From the chemical composition produced for SiO2 is deemed acceptable for paper, paint, mid-temperature refractory, glazes and clay wares ceramics but low values of Al2O3 and high values of Fe2O3. Ombaka (2016) determined the characteristics and categorization of clay-based substances for prospective applications in Rugi Ward, Kanya. The chemical and physical characteristics of the clayey minerals govern their employment in the process industries and beneficiation necessary before usage. The study aimed at establishing the potentiality of clayey minerals from the study area, and the possibilities of exploring and utilising them in order to accelerate industrial development and improve economic self-reliance of Kenya as a nation. It was shown that the clay samples composed of albite (5 - 16.7 %), kaolinite (11.4 - 36.2 %), microcline (15.2 - 35.3 %), quartz (24.3 - 68.1 %), hornblend (7.6% in samples from Nyamwa alone) and other mineral impurities in tiny amount. The data shows that clayey minerals from the research area can be utilised for commercial manufacturing of ceramic products following beneficiation using low cost and environmentally friendly processes in order to reduce the amounts of iron, quartz, and other impurities to acceptable levels. Ituma et al. (2018) explored the application of Nkpuma-Akpatakpa clay in ceramics; characterization and micro structural research. Chemical, mechanical and spectral analysis of the clay was carried out to acquire additional information from this clay found in commercial quantity at Ebonyi State Nigeria. The examined samples were constituted of quartz, qandilite, aragonite, muscorite and aratase. Porosity for the clay was too much for refractory, World Journal of Advanced Research and Reviews, 2025, 27(03), 001-015 3 thermal insulation and other high porosity desirable ceramics applications. Chemical evaluation demonstrated the presence of fluxing oxides at elevated levels which are responsible for the poor refractoriness and limits the application of the low or mid-temperature ceramics products. Characterising the Dabagi clay deposit for its potential in ceramics was studied by Abubakar et al. (2014). In addition to conducting physical property tests for bulk, density, permeability, linear distortion, thermal shock resistance, and cold crushing strength refractoriness, X-ray florescence spectrometry was used for the chemical analysis. The findings of chemical examination indicated that the clay was constituted of silica (SiO2), 64.50 %; alumina (Al2O3) 16.30 %; iron oxide (Fe2O3), 14.20%; calcium oxide (CaO), 0.2%; potassium oxide (K2O), 0.74 %; titanium oxide (TiO2), 1.71 % and other oxides in traces. While the physical investigation showed that the clay has an apparent porosity of 28.46 %, bulk density of 1.81 g/cm3, linear shrinkage of 6.8% thermal shock resistance of seven cycles, loss on ignition test 4.46 %, cold crushing strength of 14138 nm2 and estimated refractoriness of 1,349 °C. Research on analysis of Mbaukwu clay from Awka, South Anambra State, Nigeria, for Industrial Purposes was conducted by Chikwelu et al. (2018). The sample was examined for making plasticity, shrinkage, moisture, apparent thickness, volumetric density, loss on igniting, modulus of rupture, and water absorption applying established procedures. The findings of the chemical investigation revealed that: SiO2: 42.97%, Al2O3: 23.34%, Fe2O3: 4.95%, Na2O: 2.04%, K2O: 3.67%, MgO: 2.93%, CaO: 3.48%, MnO: 0.97%. Physical study indicated a mean modulus of plasticity to be 3.43 kg/cm3, mean making moisture (26.24%), total shrinkage range from 13.515.4%, apparent porosity from 33.65-28.95%, bulk density of 1.66-1.71 g/cm3 throughout a temperature range of 900-1200 °C and LOI of 14.55%. The clay is fairly pure due to its alumina/silica ratio (Al2O3:SiO2) of 0.54 comparative to 0.84 for pure kaolinite. The study also suggested that Mbaukwu clay could be suitable for manufacture of some ceramic industrial items like tiles, table ware and other ceramics wares production. Research on fabrication of electrical porcelain insulator using ceramic raw materials of Oromia region, Ethiopia was carried out by Merga et al. (2019). The raw materials mineralogy, chemical composition, and thermal characteristics determined by utilising x-ray diffractometer (XRD), atomic absorption spectrometer (AAS) and thermogravimetry (TGA), respectively. Based on the raw material’s chemical composition, five distinct porcelain insulator test bodies were created at firing temperature of 1000 °C, 1100 °C, 1200 C and 1300 °C. Water absorbance, apparent porosity, bulk density, dielectric strength and microstructure of burnt porcelain insulators were examined as a function of firing temperature. The XRD and AAS results revealed that in Bombowha clay, kaolinite mineral was discovered to be a main mineral constituent with appreciable silica (46.84 wt%) and alumina (36.74 wt%) content with moderate plasticity (PI 1/4 19-21%). The porcelain insulator body that was tested had better characteristics than the others. It was composed of 45% kaolin, 45% feldspar, and 10% quartz. It had a water absorbance of 0.010%, porosity of 0.088%, density of 2.466 g/cm3, dielectric strength of 8 Kv/mm, and a firing temperature of 1300 °C. Additionally, it had enough glassy phase to contain the quartz and mullite phases. Therefore, the experimental result verified that standard porcelain insulator can be produced from locally accessible ceramic raw materials (clay and quartz) in Ethiopia at optimal condition. 2. Materials and Methods The fieldwork and sampling activities involved the use of several materials such as a Brunton map, sample bags, hammer, spade, topographic maps, GPS device, clinometer, measuring tape, hammer, spade and digital camera. The sample preparation process involved the utilization of sealing bags, grinding equipment, sieve and a jaw crusher. The laboratory was equipped with an X-Ray Fluorescence Spectrometer (XRF), pressing equipment, sample mill, oven for chemical and mineralogical characterization. The necessary materials for the physical testing were grooving tools, plasticity cans, an electronic balance, a kiln, hydraulic press and a furnace. The area was dug using a digger while a soil auger was used to collect the soil from the desired depth and stored in an air tight container. A little portion of the soil was immersed in a beaker containing distilled water where the pH and conductivity were measured and recorded. The temperature of the soil was also determined insitu by creating a contact between the thermometer and the soil. The research area consists of clay deposits found in sand mining pits located in the Nkemkol location, Ogoja local government area of Cross River State, Nigeria. A total of four samples (A, B, C and D) were chosen within the latitude range of Latitude: 6° 39' 30.24" N and the longitude range of 8° 47' 57.23" E. Figure 3.1 displays the spatial arrangement of sampling locations within the area of Nkemkol. World Journal of Advanced Research and Reviews, 2025, 27(03), 001-015 4 Figure 1 Geological map of Ogoja 2.1. Field Sampling To extract the fine-grained, smooth clay sediments, excavation tools such as picks and hammers were utilized. The extraction process focused on sediment layers located between 3 to 5 meters deep within designated mining pits. Access to these clay deposits as shown in figure 3.2 was contingent upon the successful removal of the overburden layer. This overburden, characterized by its reddish-brown hue, consisted of a composite of lateritic soil, consolidated sandstone, and/or loose sand. The process involved systematically removing this overburden to expose the underlying clay unit. The clay layer, once uncovered, appeared as substantial bedrock formations with a range of colors including white, light grey, and brown. Within this clay matrix, occasional inclusions of friable sandstone were also observed. These sandstone fragments exhibited a crumbly texture, differentiating them from the more solid and consistent clay bedrock. The removal of the overburden layer was a critical step in the mining operation, as it allowed for the efficient extraction of the clay sediments. The reddish-brown overburden not only consisted of various soil types but also included different sedimentary rock formations, each requiring distinct handling techniques to avoid contamination of the clay. As the overburden was stripped away, careful attention was given to minimize disturbance to the underlying clay unit. This ensured that the quality of the clay remained intact for its intended use. Overall, the extraction process was methodically executed to maximize accessibility to the clay sediments while effectively managing the removal of the overburden. The use of picks and hammers facilitated the precise extraction of the clay, while the careful handling of the overburden helped in revealing the clay unit in its natural state, albeit with the occasional presence of friable sandstone elements. 2.2. Sample Preparation After being allowed to air dry for two weeks, the clay samples were mechanically crushed with a jaw crusher until they were reduced in grain size to less than 150 microns. A portion of the powdered fraction, around 40 grammes, were brought to the lab for mineralogical and chemical analysis and kept in sealed bags. For physical testing, the bulk sample that remained was kept. To prevent cross-contamination, the crusher was completely cleaned before each new sample. 2.3. Chemical Analysis The major oxide composition of the clay fraction was systematically analyzed using X-Ray Fluorescence (XRF) Spectrometry. To prepare the samples for accurate analysis, the clay was first milled to achieve a fine particle size of less than 150 microns. Each sample, consisting of approximately 30 to 40 grams of powdered clay, was carefully placed into sample cups. The XRF spectrometer was operated within a voltage range of 35 to 40 kV, which is crucial for optimizing the detection of various elements. During the analytical process, diffraction spectra were recorded, capturing the unique fluorescence emitted by the different elements present in the clay. These spectral data were then compared World Journal of Advanced Research and Reviews, 2025, 27(03), 001-015 5 against a comprehensive database to match the peaks observed. This comparison allowed for the precise determination of the weight percentages of the major oxides in the clay sample, providing detailed insight into its chemical composition. 2.4. Physical Test A comprehensive series of tests was conducted to assess the practical performance characteristics and industrial applicability of the Ogoja clay deposits. These evaluations aimed to determine the clay’s suitability for various applications and were carried out following established standards. The tests included assessments of the liquid limit, plastic limit, and plasticity index, all performed in accordance with ASTM D4318. These parameters are critical for understanding the workability and behavior of the clay under different moisture conditions. Additionally, the firing shrinkage of molded clay bars was measured following the procedure outlined in ASTM C326. This test provides insights into how the clay contracts upon heating, which is essential for predicting dimensional stability during industrial processing. The evaluation also encompassed the physical properties of the clay, such as apparent porosity, water absorption, bulk density, and apparent specific gravity. These properties were assessed according to ASTM C20 standards, providing a comprehensive understanding of the clay’s density and porosity characteristics, which are crucial for its performance in manufacturing applications. To further evaluate the material’s structural integrity, the compressive strength of cubic clay specimens was determined. This measure is vital for understanding the clay’s loadbearing capacity and its potential use in construction and manufacturing applications. Additionally, the refractoriness of the clay was predicted based on its chemical oxide content. Refractoriness is a critical attribute for materials used in high-temperature applications, as it determines the clay’s ability to withstand thermal stress without deforming or melting. Together, these tests provide a detailed assessment of the Ogoja clay deposits, offering valuable insights into their practical performance and potential industrial applications. 3. Results The results obtained in this study are presented in figures 2 to 10. and in tables 1 and 2. Figure 2 Linear shrinkage World Journal of Advanced Research and Reviews, 2025, 27(03), 001-015 6 Figure 3 Loss on ignition Figure 4 Plasticity World Journal of Advanced Research and Reviews, 2025, 27(03), 001-015 7 Figure 5 Making moisture Figure 6 Chart of the apparent porosity, apparent density and bulk density World Journal of Advanced Research and Reviews, 2025, 27(03), 001-015 8 Figure 7 Liquid limit, plastic limit and plastic index Figure 8 Cold crushing test World Journal of Advanced Research and Reviews, 2025, 27(03), 001-015 9 Table 1 Cold crushing test Sample Cold crushing test (Nmm2) A 23.8 B 15.9 C 20.6 D 28.15 Table 2 Major oxide composition of the studied clay compared to industrial specifications Studied sample Industrial Specifications Elemental Oxides A B C D Mean Range Crm % Rf % Bld % SIO2 56.39 56.46 56.76 54.38 55.88 54.3856.70 45.3047.90 67.5 51.0070.00 Al2O3 29.6 29.02 30.1 29.25 29.38 29.0231.23 37.9038.40 26.5 25.0044.00 Fe2O3 4,66 4.75 4.88 4.95 4.63 4.06-4.98 13.4013.80 0.501.20 0.2-0.7 TiO2 1.13 1.25 1.19 1.27 1.23 1.13-1.34 - - - CaO 1.66 1.75 1.81 1.69 1.7 1.61-1.81 0,03-0.25 0.180.30 0.1-0.2 P2O5 - 0.04 0,04 0.05 0.04 0.04-0.05 - - - K2O 0.89 0.98 0.76 0.88 0.88 0.76-1.01 0.10-0.40 1.103.10 - MnO 0.07 0.08 0,08 0.06 0.07 0.06-0.08 - - - MgO 4.69 4.99 4.99 4.84 4.81 4.29-4.99 0.20-0.30 0.100.19 0.2-0.7 Na2O 0.87 0.9 0.72 0.82 0.84 0.72-0.90 0.20-0.35 0.201.50 0.8-3.5 LOI 0.04 0.02 0.02 0.03 0.03 0.02-0.05 Sum 100.03 100.24 101.35 98.22 SiO2/Al2O3 6.565 6.6955 6.7657 6.8091 Al2O3/SiO2 0.5249 0.5139 0.5303 0.5378 SiO2/Al2O3 1.9051 19,455 1.8857 1.8591 Na2O/K2O 0.9775 0.9183 0.9473 0.9318 Al2O3/Fe2O3 34.26 33.71 34.98 34.2 CIA 89.6426 88.882 90.1467 89.6139 CIW 921,257 91.8354 92.2463 92.0969 *CIA – Chemical Index of Alteration; *CIW – Chemical Index of Weathering