Evolution of Metakaolin Thermal and Chemical Activation from Natural Kaolin

Sánchez, Isabel Ortega; García, Isabel Sonsoles de Soto; Casas, Marina; Villa, Raquel Vigil de la; García-Giménez, Rosario

doi:10.3390/min10060534

Cited by 10 publications

(14 citation statements)

References 34 publications

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“…Natural kaolin clay was converted to active kaolin (metakaolin) by calcination at 550 °C for 2 h in an electric heater [25]. Table 1 shows the chemical composition of kaolin clay.…”

Section: Preparation Of 13x Zeolitementioning

confidence: 99%

Comparative Study on the Catalytic Performance of a 13X Zeolite and its Dealuminated Derivative for Biodiesel Production

Alshahidy

Abbas

2021

Bull. Chem. React. Eng. Catal.

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Natural kaolin clay was used to successfully prepare 13X zeolite catalysts, which were modified by dealumination with citric acid. Acid leaching eliminates impurities and aluminum, and improves the Si/Al ratio of the zeolite framework. The X-ray diffraction (XRD) patterns of both the original and modified 13X zeolites were the same, indicating that the crystalline frameworks were not destroyed during the dealumination process. X-ray fluorescence data of the dealuminated 13X zeolite showed an improved Si/Al ratio. Also, Atomic Force Microscopy (AFM) was used for the characterization of the catalysts. The catalytic performance of the original and modified catalysts was tested in the esterification reaction of oleic acid in a batch reactor. A higher conversion of oleic acid was obtained using the modified 13X zeolite. The resulting experimental data from the esterification reactions were fitted to the heterogeneous Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetic model to determine the rates of reaction. The results of the reaction kinetics showed an increase in the rate of reaction velocity and a distinct decrease in the activation energy when using the modified zeolite, indicating that employing the modified catalyst will give a higher conversion over a shorter time through a reaction with less sensitivity to temperature. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

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“…Natural kaolin clay was converted to active kaolin (metakaolin) by calcination at 550 °C for 2 h in an electric heater [25]. Table 1 shows the chemical composition of kaolin clay.…”

Section: Preparation Of 13x Zeolitementioning

confidence: 99%

Comparative Study on the Catalytic Performance of a 13X Zeolite and its Dealuminated Derivative for Biodiesel Production

Alshahidy

Abbas

2021

Bull. Chem. React. Eng. Catal.

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“…They have many pores due to the modification as a result of the calcination process. The presence of characteristic kaolinite profiles ("structures") with dense surfaces and varying dimensions has been confirmed by the studies [2,3]. There was increase in quantity of MK produced with increase in calcination temperature, which promotes the dissolution of kaolinites and generates more gels to bind the quartz powder as supported by [18].…”

Section: Surface Morphologymentioning

confidence: 72%

“…MK is a kind of pozzolan that demonstrates enhanced cementitious behaviour. An amorphous aluminate silicate is formed when KC is dehydroxylated at temperatures between 500 and 800°C [1][2][3][4]. KC is a naturally occurring granular white rock that is rich in hydrated aluminium silicate and is characterized by the mineral kaolinite.…”

Section: Introductionmentioning

confidence: 99%

Potential of Carica Papaya Stem Activated Carbon in Removal of Undesired Compounds from Metakaolin

Adetoro,

Abdulwahab,

Adetoro

et al. 2024

Trends Sci

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Metakaolin (MK) is a pozzolan exhibiting additional cementitious tendency and is made by dehydroxylating Kaolin Clay (KC). In this study,potential of Carica papaya Stem Activated Carbon (CPSAC) in removal of undesired compounds or impurities from MK was examined.Carica papaya Stem (CPS) was processed into powder and chemically activated using hydrochloric (HCl) acid, while MK was produced from KC through calcination process.Five conical flasks contained 5 to 25 % CPSAC at 5 % weight intervals. Two hundredg of MK or KC was added and well mixed to achieve homogeneity.The KC+CPSAC samples were subjected to calcination inside a muffle furnace at 700 °C and removed after 1 to 2 h then allowed to cool; while the MK+CPSAC samples were soaked in water (125 mL for each sample) for 24 h, thereafter oven-dried at 105 °C. Subsequently, the samples obtained were subjected to Scanning Electron Microscopy (SEM) analysis to investigate their surface morphology, while X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) techniques were employed to ascertain their chemical and mineralogical compositions, respectively.The data obtained from chemical composition analyses were thereafter subjected to optimization studies.The SEM plates showed thatthe sizes of all thesamples were within ranges of 2 and 50 nm, and their intensity pinnacles from XRD plots ranged between 200 and 4000 cps. CPSAC (21.42%) eliminated the unwanted compounds in the MK andincreasethe amount of its major oxides (Al2O3, CaO, SiO2 and Fe2O3by 43.76,16.89, 12.76, 6.51 %, respectively). In conclusion, CPSAC showed potential as a viable industrial treatment material for MK. HIGHLIGHTS Remediation of unwanted compounds from MK CPSAC’s efficacies in soil (MK) remediation Treatment effects of calcination process and agricultural adsorbent on MK Optimization studies of MK compounds GRAPHICAL ABSTRACT

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“…Using a muffle furnace, the clay was heated at 600 °C for 4 h with no N 2 or air flow. 17 The material remained inside until it cooled down to ∼100 °C, followed by its further cooling in the desiccating chamber. Characterization was performed intermittently using the stored samples.…”

Section: Methodsmentioning

confidence: 99%

Understanding Iron Impurities in Australian Kaolin and Their Effect on Acid and Heat Activation Processes of Clay

et al. 2023

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Iron impurities present in the crystal structure of kaolin minerals or in accessory species are frequently encountered in clay deposits. As knowledge of the location and states of the iron is crucial when modifying the properties of clays by activation, it is important that new deposits are well characterized in terms of the amount and location of this metal. The Western Australia Noombenberry deposit has been identified as a large resource of kaolin composed largely of halloysite and kaolinite. We sampled six from one hundred drill holes and grouped them according to major mineral and iron impurities. First, we characterized them to understand the source of iron impurities. Then, we performed three physicochemical activation processes of samples involving acid treatment (by 3 M HCl), heating at 600 °C, and a combination of both. State-of-the-art tools, including X-ray diffraction, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy, and nuclear magnetic resonance, revealed the properties of kaolin, iron impurities, and the changes incurred after activation. The iron impurities were found to be linked to non-kaolin minerals, i.e., in mica or illite. Once the iron was removed mainly by acid activation, the surface area, pore volume, and negative surface charges increased, and that was significant for halloysite-rich samples. These properties helped adsorb N2 gas compared to the raw kaolin. Therefore, knowing the iron’s location and states in associated mineral species and their dissolution/retention may expand the scope of material development for gas adsorption. They are also useful in other applications like clay purification and adsorbent or additive formulations.

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Evolution of Metakaolin Thermal and Chemical Activation from Natural Kaolin

Cited by 10 publications

References 34 publications

Comparative Study on the Catalytic Performance of a 13X Zeolite and its Dealuminated Derivative for Biodiesel Production

Comparative Study on the Catalytic Performance of a 13X Zeolite and its Dealuminated Derivative for Biodiesel Production

Potential of Carica Papaya Stem Activated Carbon in Removal of Undesired Compounds from Metakaolin

Understanding Iron Impurities in Australian Kaolin and Their Effect on Acid and Heat Activation Processes of Clay

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