Papers by Keyword: Kaolin

Abstract: Zeolites being used as builders in detergents are synthesized from expensive chemicals with a cumbersome production process. In this study, zeolite was synthesized from cheaper and readily available kaolin for possible use in detergent production. Kaolin from two sources namely Ajebo, Ogun State and Darazo, Bauchi State, Nigeria was used as starting materials while wet beneficiation followed by acid leaching was used to purify the kaolin and hydrothermal process was used to synthesize the zeolite. The chemical analysis confirms the presence of silica and alumina which are the precursors materials for zeolite synthesis. An increase in the amounts of the desired silica and alumina for both kaolin accompanied by a reduction in the amounts of the undesired oxides present in the kaolin as impurities are clear indications that the acid leaching was successful. The zeolites synthesized from both kaolin shows better water adsorption capacity and ion exchange capacity compared to those reported for zeolite synthesized from pure chemicals, this ability makes zeolite more suitable for the production of detergent. These results are indications that zeolites synthesized from kaolin can serve as a possible replacement for the more expensive zeolite synthesized from chemicals used as builders in detergent production.

Abstract: Kaolin is one of the most vital industrial minerals whose application is reliant on its chemistry and structural makeup. This research attempts to determine the properties of unfired kaolinitic clay bricks for sustainable construction. Samples of the material were pre-treated and analyzed to obtain their physical and refractory properties, such as chemical composition, microstructure, moisture content, dry density, linear shrinkage, plastic index, and crushing strength. The results revealed that the clay comprises high percentages of silicon and alumina oxides being 75.6% and 17.0% of the total oxide composition respectively. The clay also contained some residual impurities in the form of metallic oxides i.e., oxides of iron, sodium, calcium, potassium, manganese, and lead. Characterization tests on the clay presented a specific gravity of 2.66, liquid limit of 38, plastic limit of 25.9, and plasticity index of 12.1 which classifies the clay as low-plasticity clay based on the Unified Soil Classification System. The river sand used was distributed between 0.06 – 3 mm falling within the category of medium and fine sand. The aggregate fineness modulus was obtained as 3.03%. The coefficient of uniformity was lower than 4.0 and thus classified as being uniformly graded. Stabilization of the clay with sand and lime resulted in decreased compression and flexural strength but increased durability. The results imply that kaolinitic clay can be used in an unfired form for earth construction.

Abstract: During the calcination of kaolin particles, kaolinite is thermally activated at high temperatures, causing the crystal structure to collapse and yielding amorphous metakaolinite through dehydroxylation. This metakaolinite is used as a supplementary cementitious material, and one of the most important factors influencing the pozzolanic properties is calcination conditions. Fourier transform infrared spectroscopy (FTIR) has become useful in distinguishing and obtaining information about structural order-disorder and phase transformation following the calcination process. In this study, water-washed kaolin particles were thermally activated at elevated temperatures ranging from 600 to 800 °C for 3–4 h at a rate of 10 °C/min before being analyzed with FTIR to determine the optimum conditions for calcining kaolin particles by examining functional groups, and also to study structural order-disorder or crystallinity of calcined kaolin particles. The most reactive metakaolinite state of water-washed kaolin particles was achieved after 3 h of calcination at 800 °C. Using both empirical and numerical approaches, variations in the position and relative intensity of O-H stretching and deformation of hydroxyl groups in the infrared spectrum can be used to classify the degree of structural order of water-washed kaolin particles. By increasing the calcination temperatures and period, the well-ordered and partially-ordered structures of kaolin particles were transformed into well-ordered, partially-ordered, and poorly-ordered structures. These structural disorder and crystallinity have a significant impact on pozzolanic activity because well-ordered kaolinite can be transformed into less reactive metakaolinite, whereas poorly-ordered kaolinite with high defects can be transformed into more reactive metakaolinite. However, in this study, the structure of water-washed kaolin particles that achieved complete dehydroxylation was discovered to be partially-ordered to poorly-ordered and can be transformed into highly reactive pozzolans.

Abstract: Desiccation is the process of extreme drying that results in cracking in materials such as soils. Cracking is a complex process that has the potential to spread and penetrate deeper into the soil, which could lead to instability in earth structures like embankments. A number of desiccation tests were conducted to observe the crack behaviour of manufactured kaolin clay at laboratory scale. All samples were prepared at variation of initial water content and desiccation tests carried out using aluminium desiccation trays. Their crack behaviour was monitored at different thickness and comparison made to the samples tested on different base materials such as ceramic, steel and wood plates. The drying process, crack propagation and pattern were measured and observed daily. A digital image is captured and the crack intensity factor (CIF) calculated manually using a grid system. It was found that a sample of kaolin clay that was 5 mm thick had the highest CIF with rapid propagation and produced non-orthogonal patterns. It also discovered that the thickness of the samples, type of plates utilised and soil state at the start of the test have an impact on the formation and propagation of cracks.

Abstract: The current study ensures the possibility of improving the mechanical and dielectric properties of polystyrene/kaolin reinforced with glass fibers. Polystyrene was dissolved using coloring in a ratio of 1 to 2. The prepared composites were studied and the results of the tensile, impact, hardness, thermal conductivity, and dielectric, has been obtained. Through the tensile results, it was found that with an increase in the addition of kaolin, both the yield points and the Young modulus decreased with a small and noticeable increase for the sample with the percentage of addition beyond 8 percent in Elongation, and shown high flexibility. The highest tensile strength appeared in the pure sample (x= 0%), where the value reached 22.85 MPa, while the lowest was for the sample with ratio 2%. While the impact result showed a noticeable increase with the increase in the percentage of addition of kaolin in the few percentages only. The sample with an addition rate of 8% kaolin, showed a high rebound energy, through the results of the energy absorption test, and it had the highest thermal conductivity and dielectric coefficient.

Abstract: Crude petroleum filters were prepared from low-cost materials based on kaolin powder and combustible materials as palm fronds powder which acts as pore creating agent. The samples with different content (10, 20, 30,40) wt% of palm fronds powder (P.F) were fabricated using a dry pressing method and fired at 1100 °C. Crude petroleum filters were characterized by X-ray diffraction (XRD), energy dispersive analysis (EDS) and Scanning electron microscopy (SEM). Physical properties (linear shrinkage, apparent porosity, water absorption, apparent density), mechanical properties (compressive strength and diametrical strength ) and Metallic Content.

Abstract: In this study, Natural Rubber Vulcanizates (NRV) reinforced with organomodified kaolin was developed. The NRV were subjected to thermal degradation to ascertain its suitability for high-temperature automotive applications. Kaolin intercalation was achieved using derivatives of Rubber seed oil (Hevea brasiliensis) and Tea seed oil (Camellia sinensis) in the presence of hydrazine hydrate as co-intercalate. The developed Natural Rubber Vulcanizates were characterised using Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) Spectroscopy and Scanning Electron Microscopy (SEM). FTIR spectra obtained for the organomodified natural rubber vulcanizates revealed the presence of carbonyl groups at bands 1564cm^-1 and 1553cm^-1 which is an indication of organomodified kaolin intercalation within the Natural Rubber matrix for kaolin intercalates of Rubber seed oil and Tea seed oil respectively while no value was reported for the Natural Rubber vulcanizates obtained from the pristine kaolin filler. TGA results indicated that NRV developed from kaolin intercalates of Rubber seed oil (RSO) with onset degradation and final degradation temperatures of 354.2°C and 601.3°C were found to be the most thermally stable of the Natural Rubber Vulcanizates investigated. The SEM micrograph revealed that the kaolin nanofillers in Rubber Seed Oil modified Natural Rubber Vulcanizates were well dispersed as compared to that of Tea Seed Oil modified Natural Rubber Vulcanizates.

Abstract: High-alumina chamotte with an Al₂O₃ content of more than 62% is a desirable raw material to produce high-alumina refractories. The production of high-alumina aggregate (chamotte) is carried out in various ways, using plastic or semi-dry technology for briquetting from commercial alumina and refractory clay. When grinding fused corundum, the dust containing 93–95% Al₂O₃ is formed; it is currently a substandard material. It is of interest to involve this waste product in the production of high-alumina chamotte. The developed technology allows obtaining the desirable material and utilizing production waste. In this project the briquetting parameters to produce high-alumina chamotte using corundum waste and refractory enriched kaolin were determined.

Abstract: Plastic is materials that are not easily broken down, so it can cause a variety of complex problems such as loss of natural resources, environmental pollution, and depletion of landfill space. Plastic favored by the public is Polypropylene (PP) and High Density Polyethylene (HDPE) for example, food storage, transparent drinking glasses and drinking bottles for babies. This will be a problem in the future. Some alternatives used to reduce the volume of plastic waste are the thermal transformation process which is divided into three types of processing, namely combustion, gasification, and pyrolysis. Pyrolysis is a process of thermal degradation of long chains into smaller molecules. The process of pyrolysis in this study used a variety of catalysts (without catalyst, 5%, 10%, 15%, and 20%) and used variations in particle size, namely size I (30 cm³); size II (7.5 cm³); size III (1,875 cm³) weighing 350 grams of plastic cups and 350 grams of bottle caps. Pyrolysis run for 100 minutes and took the result of pyrolysis every 20 minutes interval. The test carried out by using proximate analysis, fuel specification analysis, and GC-MS. Based on the result of research conducted on the pyrolysis process of a mixture of HDPE and PP variations of catalysts, it obtained optimum liquid and gas yields of 98.57% and 1.43%. Besides, in the size variation, the optimum liquid and gas yield was 96.57% and 3.43%. The proximate result has fulfilled the conditions set by the value of ash content, fly substance, and carbon bound 0.15%; 99.57%; 0.28%. In the GC-MS (Gas Chromatography-Mass Spectrometry) test the highest % area was 39.18% with C₉H₁₈ or 2,4-dimethyl-1-heptane compounds. The best simulation result obtained the value of activation energy and reaction speed for liquid and gas in the variation of the catalyst of (87,930.07; 101,527.17) J/mol and (2.03 x 10²; 3.74 x 10³).

Abstract: Soft soil is normally associated with high moisture content and fine content which result in high compressibility and low strength. However, a proper treatment such as solidification by means of hydraulic binders is required in order to be usable for beneficial purposes (e.i backfilling). This paper experiments the effects of cement treatment on the one-dimensional (1D) consolidation behavior of a high moisture content (MC) soil (twice liquid limit), based incremental loading test. The effects of Portland cement addition are evaluated for dosages ranging from 0 % to 15% by dry mass of soil. After curing, it was found that 10 % cement was required to make meaningful reduction in MC for kaolin while no major difference was noted between after mixing and after curing for DMS. In kaolin the moisture content decreased by 6.5 % for each 5 % increment of cement. Similarly, the MC of DMS reduced by 10 % for each 5 % increment. Thus, the reduction, immediately after mixing, in DMS was higher by 3.5 % compared to kaolin. The most evident effect of the treatment feasibility is the development of a cementation-induced yield stress after 7 days of curing: the bigger the cement dosage, the greater the yield stress and the greater the vertical effective stress that can be sustained at any void ratio. The maximum yield stress at 15 % cement content was found 30 kPa and 70 kPa for DMS and kaolin respectively. The highest void ratio values were found in the control specimens (3.77) in kaolin and DMS (5.66) whereas the lowest void ratio was corresponded to 15 % cement 3.35 and 4.65 for kaolin and DMS respectively. The control specimens decreased dramatically from 38.93 m² / KN - 0.13 m² / KN and 36.03 m² / KN - 0.19 m² / KN for kaolin and DMS specimens respectively. The results correspondingly provide a consistent depiction of the effects of cement treatment on MC, void ratio and coefficient of volume compressibility. The effectiveness of the treatment is obvious compared to the untreated soil.