Addition Of Kaolin Research Articles

The addition of Nigerian Kankara kaolin improves the ash properties of empty fruit bunches during combustion

The addition of Nigerian Kankara kaolin improves the ash properties of empty fruit bunches during combustion

Influence of calcined and hexadecyltrimethoxysilane modified kaolin on morphology, tensile, and thermal properties of hybrid thermoplastic composites

The purpose of this study is to investigate the incorporation effect of kaolin clay on the mechanical and thermal properties of PP/kaolin composites. Its performance is studied as a function of powder content in the different particle size. To improve the dispersion of the mineral clay and the interfacial interactions between matrix and filler, maleic anhydride grafted polypropylene (PP-g-MA) was used as a compatibilizer. Also, the filler surface was modified with a silane-coupling agent (hexadecyltrimethoxysilane). The change of the kaolin structure into metakaolin by calcination was carried at 600°C. The results show that silane modified kaolin leads to a better dispersion and to a better mechanical and thermal properties. However, addition of untreated kaolin increases E− modulus of about 32 at 5% wt content. Elongation at break was also enhanced in the presence of calcined and silane modified kaolin as compared to untreated composites. Thermal stability was found to increase with 2.5% of compatibilizer in PP/kaolin composites.

The Addition of Different Adsorbents In SA-PVA Matrix For Bacillus Subtilis Immobilization on Methylene Blue Decolorization

Wastewater which is not handled by a proper treatment before released in the water body, can cause damage for aquatic biota and its environment. MB is a synthetic textile dye which is toxic and difficult to degrade. Bioremediation by decolorization using microbes such as bacteria is one of the best methods for dye removal. By immobilizing Bacillus subtilis bacterium in an appropriate matrix, it could have more advantage on dye decolorization than by free cell only. The sodium alginate (SA) and polyvinyl alcohol (PVA) are well known as good matrix for decolorization. Besides the addition of B. subtilis in the SA-PVA matrix, the addition of adsorbents could enhance the decolorization. In this study, different adsorbents: bentonite, activated charcoal, kaolin, and corncob powder were investigated for influencing MB decolorization by immobilized B. subtilis in SA-PVA matrix. The result showed that the highest MB decolorization was reached by SA-PVA-B. subtilis with the presence of activated charcoal by approximately 88% of 100 mg/L, followed by the addition of bentonite (82%), kaolin (80%), and corncob powder (79%). The MB decolorization by SA-PVA-Activated charcoal-B. subtilis reached optimum condition at temperature 35 °C, 24 h incubation time in static condition.

Mechanistic study of PM2.5 reduction by kaolin-limestone compound additive in pulverized coal combustion

A novel compound additive prepared from kaolin and limestone shows promising prospects for in-furnace abatement of combustion PM2.5 (particulate matter with aerodynamic diameters equal to or less than 2.5 μm). However, the mechanisms need further clarification. These were investigated by combustion of a low-alkali coal on a high-temperature drop tube furnace (DTF). Combustion experiments with the kaolin-limestone additive were carried out at 1300 °C and in simulated air. Baseline tests of individual additives (i.e., kaolin and limestone) were also performed for comparison. Particulate samples were collected and classified by a Dekati low pressure impactor (DLPI). Heat-treated additive samples were also collected by DLPI and filter. They were characterized by various techniques such as laser diffraction particle sizing, X-ray diffraction (XRD), and field emission scanning electron microscopy equipped with energy dispersive spectrometry (FESEM-EDS). The results show that the addition of kaolin or limestone suppresses the emission of aerosols between 0.3 and 2.5 μm (PM0.3-2.5), but unexpectedly increases that of ultrafine aerosols less than 0.3 μm (PM0.3). The latter is primarily attributed to the carryover of ultrafine additive particles. Due to different effects on the two particle size fractions, the individual additives are found to have overall insignificant effects on PM2.5 emission. In striking contrast, the addition of the kaolin-limestone additive leads to an apparent reduction of both PM0.3 (∼46%) and PM0.3-2.5 (∼37%). As a result, a significantly high reduction of PM2.5 by ∼ 40% is achieved. The superior performance of the compound additive, compared with the individual additives, is accounted for by enhanced interactions between kaolin-limestone, additive-vapor, and additive-ash. These mechanisms, together with the collision-induced particle capture mechanism proposed previously, are believed to play key roles in PM2.5 abatement in real boilers when the compound additive and fuel are premixed.

The potential of polyvinylidene fluoride (PVDF)-kaolin membrane for water treatment

Polyvinylidene fluoride (PVDF)-kaolin membrane has been successfully fabricated. The addition of kaolin is aimed to optimize the performance of PVDF membrane for water treatment. Kaolin was prepared using 0.1 N HCl to activate the material. The fabrication of membranes was using phase inversion with 6 variations on PVDF composition within the membrane. FTIR analysis on kaolin activation shows minor changes on peak intensities and broadness without any addition or loss peak that indicates there is no reaction and only activation is occurred. The addition of kaolin affects the pure water flux. All of modified membranes shows gradually change on porosity and hydrophobicity properties under the contact angle measurement.

Characteristic comparison of cornstarch-based bioplastics using kaolin, microcrystalline cellulose and chitosan as fillers

In the study, the basic material for making bioplastics was corn starch with the addition of kaolin, microcrystalline cellulose, and chitosan as filler variations, as well glycerol as a plasticizer. The method used was the blending method. The characterization included the absorption test for water resistance, biodegradation test, tensile and elongation strength test, and functional group analysis using FTIR. Among fillers, the best bioplastic characteristic bioplastic was obtained with filler kaolin with the water absorption value of 88.62%, a tensile strength value of 1.44 x10-3 MPa, and the elongation strength value of 5.04%. Nearly 80% of the material was degraded in 15 days. Spectra of FTIR showed the appearance of some functional groups from starch, filler, and plasticizer, which meant that the process of bioplastic manufacturing was physical mixing.

Mechanochemical remediation of fluoranthene contaminated soil and biotoxicity evaluation

ABSTRACT A mechanochemical (MC) method was employed for the remediation of soil contaminated with fluoranthene (C16H10, FL) a four-ringed polycyclic aromatic hydrocarbon (PAH) containing three benzene rings and a central five-membered heterocyclic ring, with the effects of soil inorganic components, milling conditions, and the degradation mechanism investigated. Results showed that the addition of SiO2 and kaolin to soil resulted in a greater increase in the effectiveness of FL removal than other inorganic additives. After 3 hours of milling at 500 rpm, the FL removal rate from SiO2 containing soil, reached 99.26%, with the removal efficiency increasing in accordance with an increase in milling duration and speed. The milled samples were characterized by FT-IR, Raman spectroscopy, and GC-MS analysis, revealing the mechanism of FL degradation, including destruction of the aromatic skeleton structure and the formation of amorphous carbon and graphite. The MC remediation method was applied to FL contaminated soil, showing that FL was efficiently degraded in soil without any soil additives, resulting in a significant reduction in the biotoxicity of the remediated soil. The organic matter, moisture content and pH of the actual soil changed slightly after mechanical ball milling. Thus, the MC method has high potential in the remediation of PAH-contaminated soils. HIGHLIGHTS A mechanochemical (MC) method for the degradation of fluoranthene was assessed. The use of silica and kaolin as soil additives enhances fluoranthene remediation. Fluoranthene can be efficiently removed from contaminated soil by milling alone. The degradation mechanism was skeleton structure destruction and carbonization. The biotoxicity of soil was significantly reduced by milling.

Brine desalination via pervaporation using kaolin-intercalated hydrolyzed polyacrylonitrile membranes

Polyacrylonitrile (PAN) has been mostly used as a base polymer for asymmetric membrane synthesis with the aim of pervaporation (PV) applications, since it has a superior hydrophilicity and the ability to become hydrolyzed with an alkaline solution. Nonetheless, PAN and hydrolyzed PAN membranes have shown moderate permeate fluxes along with a mechanical softness. In this study, we aimed to improve the PV performance by exploring the possible effect of the hydrolysis of a novel mixed matrix membrane based on PAN and kaolin. Specifically, 15% PAN was used as a dope solution along with varying concentrations (2, 5, 7, and 10%) of kaolin to synthesize mixed matrix membranes using a non-solvent-induced phase separation technique. The 2% kaolin addition maximized the hydrophilicity and water sorption capacity of the membrane by developing well-organized, deep channel structures with increased porosity, membrane thickness, and surface roughness. The tensile strength was also the highest with the 2% kaolin addition. Further hydrolysis of the 2% kaolin-embedded PAN caused an extra enhancement of its hydrophilicity with a decrease of pore size due to the amplified carboxylic group density. PV performance tests under different salt concentrations confirmed that the hydrolyzed PAN membrane with a 2% kaolin intercalation had an outstanding permeation flux of 82 kg m-2h−1 and 59 kg m-2h−1 as well as a salt rejection of 99.93% and 99.91% with a 3.5% and 10% NaCl solution, respectively, at a 65 °C feed temperature.

Laser sintering of coated polyamide 12: a new way to improve flammability

In this study coatings of kaolin and talc particles were successfully applied on the surface of polyamide 12 powder intended for laser sintering (LS). Microscopic observations revealed that using carboxymethyl cellulose (CMC) as surface modifier for fillers led to a better coverage of polymer grains with a surface coverage between 6 and 16% as a function of filler type and content. Differential scanning calorimetry measurements showed that the addition of talc and kaolin led to an increase in the crystallization temperature of PA12, but at the expense of processability. Process parameters were optimized in order to manufacture LS samples with the different coated powders. Fire behavior assessed by cone calorimetry showed that the use of CMC resulted in a significant decrease in the peak of heat release rate depending on the filler type and content. This behavior can be partially explained by an interaction between CMC, fillers and polymer, with the formation of amide linkage between carboxyl part of CMC and amine end groups of polyamide, resulting in an increase in the complex viscosity of materials.

Effect of Kaolin Addition on the Sinter-Crystallisation Kinetics of Compacts of a Crystallising Frit

Effect of Kaolin Addition on the Sinter-Crystallisation Kinetics of Compacts of a Crystallising Frit

Influence of kaolin and coal fly ash addition on biomass ash deposition in an entrained flow reactor

The ash deposition behavior when firing different biomass (pulverized wheat straw, wood, bark, and leaves), with and without K-capture additives (kaolin and coal fly ash) was investigated through combustion experiments in the DTU (Technical University of Denmark) entrained flow reactor (EFR). In terms of deposit formation, the K- and Cl-rich Danish wheat straw proved to be the most problematic fuel, while milled wood pellets, leaves, and bark had significantly lower deposition propensities. Kaolin and two types of coal fly ash (Al- and Si-rich) were used as K-capture additives, and the results showed that with a fuel-K/additive-Al molar ratio of 1.0, the deposition propensity of wheat straw combustion was significantly reduced. However, the deposition propensity of the combustion of milled wood pellets did not change significantly with the addition of additives. ICP-elemental analysis of the deposits and fly ash samples showed that the water-soluble K content in the deposits and fly ash was significantly reduced for both wheat straw and wood pellet combustion. In comparison with the data from previous experiments, where pure K-salt reacted with solid additives, kaolin captured KOH more effectively than real biomass combustion. For coal fly ash, an opposite tendency was observed, i.e., it captured K more effectively under real biomass combustion conditions than under pure KOH reaction conditions.

Facile Preparation of Antibacterial Gelatin-Kaolin Bionano- composite Membranes and Study of Water Sorption and Water Vapour Transmission Rate (WVTR)

Glutaraldehyde crosslinked gelatin kaolin bionanocomposite films were prepared by casting method and characterized by various techniques and water vapour transmission rates and water sorption studies were performed. The FTIR study revealed the interaction between functional groups of gelatin and kaolin evidenced by shifting of some spectral peaks. The grain size of bionanocomposite films was calculated to be 29 nm from XRD analysis and the crystallinity was 62 %. The SEM and AFM analysis suggested for heterogeneous surfaces having pores and pits. The glass transition temperature of gelatin film was found to increase from 70 to 100°C as revealed by DSC technique. The thermal properties increased with increasing kaolin. The addition of kaolin marked an increase in Young’s modulus and tensile strength. The bionanocomposite films showed a fall in water sorption capacity with increasing kaolin content. The water vapour transmission rate (WVTR) decreased with increasing addition of kaolin. The films were found to show antibacterial nature against Aureus.

Silicone pressure-sensitive adhesives with increased thermal resistance

The purpose of this work was to obtain single-sided tapes with different concentrations of kaolin and to check its impact on the self-adhesive properties of commercial adhesives. The most important self-adhesive properties were examined, such as tack, peel adhesion, shear strength, shrinkage, and thermal resistance. Tapes based on silicone PSAs with kaolin can be used in many branches of industry to bond elements operating at elevated temperatures, i.e., in aeronautics, aerospace including solar cells for satellites and space stations. There are few reports on one-sided adhesive tapes based on silicones with the addition of kaolin. However, taking into account the number of their potential applications, we did self-adhesive tests and explained how kaolin affects them. In addition, the reactivity of the crosslinking compound and silicone adhesive during the crosslinking process and the thermal effects of this process were also examined. In connection with the various applications of the obtained tapes, also the flammability and heat of combustion were tested, in accordance with applicable standards. As a result of the tests, one-sided self-adhesive tapes with new properties (increased temperature resistance, less shrinkage, and increased resistance to flammability) were obtained.

Transformation of Cr under sintering of Ca-rich solid waste with kaolin: Analysis of multi-element coupled interactions

The high toxicity of Cr–Ca compounds generated during the heat treatment of solid waste will heavily threat the environment. In this work, a kind of Ca-rich river sludge which is bound with Ca and heavy metals was combusted with kaolin under 900 °C for 3 h in a muffle to study the transformation of Cr. The effects of kaolin on Cr transformation were investigated through sequential extraction, the risk assessment of heavy metals, and constant pH leaching test, also combined with crystal phase analysis of Ca–Al–Si minerals. The experimental results showed that the formation of Ca10(SiO4)3(SO4)3Cl2 was inhibited by the addition of 10% (mass fraction) kaolin and the released Cl promoted the evaporation of target elements in priority while 30% kaolin addition further inhibited the solidification of Cr. Furthermore, the effect of NaCl and CaCO3 on the Cr solidification by kaolin were also explored by leaching procedure or XRD analysis of calcination products of their mixtures. It should be noticed that the addition of kaolin in Cr2O3–CaCO3 mixture will directly react with CaCrO4 and fixed the generated Cr2O3 into internal layered structure, preventing its re-oxidization by the free CaO. This work aims to help illustrate the Cr transformation with existence of Ca during sintering of Ca-rich solid wastes and reduce the Cr contamination in future.

Reduction of the Adverse Impacts of Fungal Mycotoxin on Proximate Composition of Feed and Growth Performance in Broilers by Combined Adsorbents.

Synergistic interaction of adsorbents in reducing the adverse impacts of mycotoxin on performance and proximate composition of broiler feeds was investigated. Fungal growth was induced by sprinkling water on the feed. S. cerevisiae + bentonite, kaolin + bentonite or S. cerevisiea + kaolin adsorbent combinations (1.5 g/kg feed) were added and the feeds were stored in black polythene bags. An untreated group was kept as a positive control while fresh uncontaminated feed was used as a negative control. Mycotoxins were extracted from the feeds and quantified using reverse phase HPLC. Proximate composition, nutrient digestibility of the feeds, feed intake and weight gain of the broilers were measured. Deoxynivalenol (DON) concentration in the contaminated/untreated feed was 347 µg/kg while aflatoxin B1 (AFB1) was 34 µg/kg. Addition of bentonite and kaolin in the contaminated feed reduced AFB1 and DON to significantly lower levels. Feed intake and weight gain were low in the broilers fed the contaminated feed. The carbohydrate level was significantly (p < 0.05) reduced from 62.31 to 40.10%, crude protein digestibility dropped from 80.67 to 49.03% in the fresh feed and contaminated feed respectively. Addition of the adsorbents (S. cerevisiae and bentonite) significantly (p < 0.05) improved these parameters.

Effects of Kaolin Addition on Mechanical Properties for Cemented Coal Gangue-Fly Ash Backfill under Uniaxial Loading

In this investigation, six groups of cemented coal gangue-fly ash backfill (CGFB) samples with varying amounts of kaolin (0, 10, 20, 30, 40, and 50%) instead of cement are prepared, and their mechanical properties are analyzed using uniaxial compression, acoustic emission, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The uniaxial compressive strength, peak strain, and elastic modulus of CGFB samples decreased with the kaolin content. The average uniaxial compressive strength, elastic modulus, and peak strain of CGFB samples with 10% amount of kaolin are close to that of CGFB samples with no kaolin. The contribution of kaolin hydration to the strength of CGFB sample is lower than that of cement hydration, and the hydration products such as ettringite and calcium-silicate-hydrate gel decrease, thereby reducing strength, which mainly plays a role in filling pores. The contents of kaolin affect the failure characteristics of CGFB samples, which show tensile failure accompanied by local shear failure, and the failure degree increases with the kaolin content. The porosity of the fracture surface shows a decreasing trend as a whole. When the amount of kaolin instead of cement is 10%, the mechanical properties of CGFB samples are slightly different from those of CGFB samples without kaolin, and CGFB can meet the demand of filling strength. The research results provide a theoretical basis for the application of kaolin admixture in fill mining.

Shear Strength Characteristics of Cemented Clayey Sand Soil

Several techniques of soil stabilization are available to improve the behavior of many types of soil. The addition of cement to soils have proved a significant effect on the geotechnical properties of treated soils. In this study, an artificial clayey sand soil samples were prepared by mixing 20% kaolin clay of fine sand. Initially, compaction tests were conducted on soil mixture to study the effect of kaolin addition on maximum dry density, optimum moisture content of mixed soil at a relative density of 55%. The mixed soils were improved by cement. Then ,a series of unconfined compression tests were performed to clarify the performance of improved soil with different cement contents at the optimum water content of each cement content ,and the samples examined after two hours from preparation, and curing period of 7 days and 14 day. Results of compaction test indicate that adding kaolin increasing maximum dry density and moisture content. Tests results show that addition of cement to soil mixture increased stiffness and unconfined compression strength (UCS), and leading to a brittle behavior.

Numerical Analysis on Reduction of Ultrafine Particulate Matter by a Kaolin Additive during Pulverized Coal Combustion

Adding additives into the furnace is an effective way to reduce particulate matter (PM) formed during coal combustion. However, a numerical model that can predict the performance of additives on PM reduction is still lacking. In this work, a numerical framework, which contains the submodels for ash formation and ash–additive interactions, was developed to predict the ash particle size distribution with and without kaolin additives. The model fully considers the physical–chemical reaction process between the combustion gaseous products (alkali metal vapor) and the Si-/Al-based adsorbent particles. The simulation results are validated by experimental measurements of PM formed during the combustion of high-sodium Zhundong coal on a lab-scale furnace. Given the typical conditions of the lab-scale furnace, adding 3% (by weight) kaolin reduces the mass yield of PM0.3 by 33.35% but has no obvious influence on PM>1. On the basis of a time-scale analysis, we show that the chemical adsorption of the mineral precursors is the dominant mechanism for PM reduction. The influences of the kaolin particle size and dosage on PM reduction are evaluated. The PM reduction efficiency quickly increases and then enters into a plateau as the kaolin mass ratio increases. When a certain critical value is reached, a further increase of the addition ratio has a negligible effect on PM reduction. The critical kaolin mass ratio is 4.1% for 2.1 μm of kaolin and quadratically increases to 4.9% for 21.3 μm of kaolin. Increasing the kaolin size, in contrast, has a negative impact on PM reduction. On the basis of the simulation results, it can be concluded that there exists an optimal condition for PM1 reduction by kaolin addition. The numerical framework developed in the current work can help to quickly find the optimal addition strategy under different additive/coal properties, combustion temperatures, and atmospheres.

Dynamic parameters of subgrade soils prone to mud pumping considering the influence of kaolin content and the cyclic stress ratio

Rail transport industry often desires to increase the freight capacities for heavy-haul trains to transport more goods. However, this requires an increase in the axle loads, which results in the railway foundation being subjected to higher cyclic stress ratio (CSR), causing significant subgrade distress. Recent laboratory investigations indicate that addition of kaolin to low-to-medium plasticity soils can avert early softening and fluidization of the soil under increasing CSR, how the dynamic parameters such as the shear modulus (G) and the damping ratio (Dp) of soils may change consequentially to this modification needs appropriate quantification. Furthermore, while there are plenty of studies correlating shear strain and plasticity index (PI) with the dynamic properties of the soil, the role of loading parameters such as the CSR and number of cycles (N) has not been thoroughly investigated. Therefore, efforts have been made to characterise the dynamic parameters of moderately plastic silty-clay soils with varying kaolin content (cK) and loading parameters. The results indicate that as CSR exceeds a critical level, G decreases rapidly whereas Dp was found to increase abruptly in few loading cycles. The paper also shows that when G diminishes about 20% from its initial value, any further loss in shear modulus would cause soil to turn into an unstable stage where the excess pore water pressure and shear strain begins to increase rapidly. Although varying the kaolin content does not alter the PI significantly, it causes a considerable effect on the dynamic parameters of the soil. Based on the current experimental findings, empirical models are proposed to estimate dynamic parameters of subgrade soils prone to mud pumping considering loading condition under heavy haul railways.

Ash characteristics of oxy-biomass combustion in a circulating fluidized bed with kaolin addition

Biomass combustion in the oxy-fuel circulating fluidized bed is a promising technology to maximize the negative carbon dioxide emission and reduce pollutants emission in power plants. However, biomass ash related behaviors under oxy-combustion with kaolin additives still lack sufficient information. In this study, kaolin was used as an additive to manage ash problems during oxy-biomass combustion in a 0.1 MWth circulating fluidized bed combustion facility. Kaolin was fed at ratios of kaolin/wood pellet (wt./wt.): 0.21 and 0.25 by separately feeding or pre-mixing, respectively. The sampled ashes were characterized using X-ray fluorescence and X-ray diffraction analysis. Additionally, the potassium capture performance, slagging and fouling indices, attrition characteristics, and strength were also evaluated. The results revealed that potassium capture performance was improved by up to 24% at the ratio of kaolin/wood pellet (0.25) and kalsilite (KAlSiO4) within ash increased by adsorption on the metakaolin surface of gaseous potassium. The fouling formation decreased from 0.43 without kaolin to 0.07–0.15 with kaolin. In terms of oxy-fuel operation, SO2 emission was decreased when kaolin used, performing a high CO2 concentration of over 93 vol% and combustion efficiency of over 99%.