Kinetic behaviour of thermal transformations of kaolinite

Ondro, Tomáš; Trník, Anton

doi:10.1063/1.5047627

Cited by 7 publications

(2 citation statements)

References 22 publications

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“…Similarly, Skinner et al reported that the dehydroxylation of HA starts above 700 • C [42]. The endothermic peak at 498 • C corresponds to the dehydroxylation of kaolinite, which is reflected in kaolin and the HA-kaolin composites [40,43]. Here, dehydroxylation of the crystalline kaolinite structure took place, resulting in the formation of a calcined metakaolin phase.…”

Section: Thermal Analysismentioning

confidence: 90%

Hydroxyapatite–Clay Composite for Bone Tissue Engineering: Effective Utilization of Prawn Exoskeleton Biowaste

Satish,

Hadagalli,

Praveen

et al. 2023

Inorganics

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Hydroxyapatite (HA, Ca10(PO4)6(OH)2)-based porous scaffolds have been widely investigated in the last three decades. HA, with excellent biocompatibility and osteoconductivity, has made this material widely used in bone tissue engineering. To improve the mechano-biological properties of HA, the addition of clay to develop HA-based composite scaffolds has gained considerable interest from researchers. In this study, a cost-effective method to prepare a HA–clay composite was demonstrated via the mechanical mixing method, wherein kaolin was used because of its biocompatibility. Prawn (Fenneropenaeus indicus) exoskeleton biowaste was utilized as a raw source to synthesize pure HA using wet chemical synthesis. HA–clay composites were prepared by reinforcing HA with 10, 20, and 30 wt.% of kaolin via the mechanical mixing method. A series of characterization tools such as XRD, FTIR, Raman, and FESEM analysis confirmed the phases and characteristic structural and vibrations bonds along with the morphology of sintered bare HA, HA–kaolin clay composite, and kaolin alone, respectively. The HA–clay composite pellets, uniaxially pressed and sintered at 1100 °C for 2 h, were subjected to a compression test, and an enhancement in mechanical and physical properties, with the highest compressive strength of 35 MPa and a retained open porosity of 33%, was achieved in the HA–kaolin (20 wt.%) clay composite, in comparison with bare HA. The addition of 20% kaolin to HA enhanced its compressive strength by 33.7% and increased its open porosity by 19% when compared with bare HA. The reinforcement of HA with different amounts (10, 20, 30 wt.%) of kaolin could open up a new direction of preparing biocomposite scaffolds with enhanced mechanical properties, improved wear, and better cell proliferation in the field of bone tissue engineering.

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Section: Thermal Analysismentioning

confidence: 90%

Hydroxyapatite–Clay Composite for Bone Tissue Engineering: Effective Utilization of Prawn Exoskeleton Biowaste

Satish,

Hadagalli,

Praveen

et al. 2023

Inorganics

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“…Kaolinite (Al 2 O 3 •2SiO 2 •2H 2 O), the principal kaolin mineral, is a 1:1 layered phyllosilicate made of one tetrahedral sheet of silica and one octahedral sheet of alumina. There are smaller metal cations in the centre of the tetrahedrons and octahedrons and their apices are filled with oxygen atoms and groups of hydroxyls [2]. Thermal decomposition at 400 °C -700 °C disrupts kaolinite's crystalline structure.…”

Section: Introductionmentioning

confidence: 99%

METAKAOLINITE: Si & Al PRECURSORS FOR KALSILITE SYNTHESIS

Yusslee¹

2021

Ceramics - Silikaty

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Metakaolinite has been used as a silica and alumina precursor to synthesise kalsilite via the hydrothermal method with the addition of potassium hydroxide (KOH) as the potassium source. The effects of the KOH concentrations and reaction temperatures have been investigated. X-ray diffraction (XRD) diffractograms and field emission scanning electron microscope (FESEM) images showed the formation of hexagonal kalsilite after the hydrothermal reaction of metakaolinite at 190 °C in 1.25 M KOH for 24 hours. Kalsilite formed as a minor crystalline phase at a KOH concentration of less than 1.0 M KOH, while, at a higher KOH concentration, the crystallinity of the product increases. On the other hand, 190 °C was sufficient to convert metakaolinite to kalsilite. Besides, zeolite F and muscovite have been found as the dominant products at a lower KOH concentration and temperature, respectively.

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