Significance of the formation of pentahedral aluminum in the reactivity of calcined kaolin/metakaolin and its applications

Moya, J.S.; Cabal, B.; Lopez-Esteban, S.; Bartolomé, J.F.; Sanz, J.

doi:10.1016/j.ceramint.2023.10.304

Cited by 13 publications

(1 citation statement)

References 101 publications

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“…In recent decades, geopolymers have been seen as an environmentally viable alternative to Portland cement because of their performance. They have attracted attention for properties such as mechanical compressive strength, low permeability, good chemical resistance and durability against acid and sulfate attack, as well as excellent fire performance [5,13,15,[33][34][35][36][37][38]40,[77][78][79][80][81][82]. It has also been reported that obtaining geopolymers as alkali-activated inorganic materials reduces greenhouse gas (GHG) emissions [81,83].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Geopolymeric Materials from Industrial Kaolins, with Variable Kaolinite Content and Alkali Silicates Precursors

Martínez-Martínez,

Bouguermouh,

Bouzidi

et al. 2024

Materials

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In the present work, the development of geopolymeric materials with Na or K based on industrial kaolin samples, with variable kaolinite content and alkaline silicates, is studied. XRF, XRD, FTIR and SEM-EDS have been used as characterization techniques. Three ceramic kaolin samples, two from Algeria and one from Charente (France), have been considered. In particular, chemical and mineralogical characterization revealed elements distinct of Si and Al, and the content of pure kaolinite and secondary minerals. Metakaolinite was obtained by grinding and sieving raw kaolin at 80 μm and then by thermal activation at 750 °C for 1 h. This metakaolinite has been used as a base raw material to obtain geopolymers, using for this purpose different formulations of alkaline silicates with NaOH or KOH and variable Si/K molar ratios. The formation of geopolymeric materials by hydroxylation and polycondensation characterized with different Si/Al molar ratios, depending on the original metakaolinite content, has been demonstrated. Sodium carbonates have been detected by XRD and FTIR, and confirmed by SEM-EDS, in two of these geopolymer materials being products of NaOH carbonation.

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Section: Introductionmentioning

confidence: 99%

Preparation of Geopolymeric Materials from Industrial Kaolins, with Variable Kaolinite Content and Alkali Silicates Precursors

Martínez-Martínez,

Bouguermouh,

Bouzidi

et al. 2024

Materials

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Investigation of Microhardness, Microstructural, Tribological, and Thermal Properties of Al7075/TiO₂/Kaoline Hybrid Metal Matrix Composites Produced by Powder Metallurgy Process

Demir,

Okumuş

2024

Adv Eng Mater

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The shift from traditional, single‐component metals and alloys continues, and researchers are currently investigating alternative materials. This evolution has led to the creation of innovative materials, including hybrid metal‐matrix composites. The present study aims to investigate the microstructural, surface morphological, and thermal properties of a novel Al7075/TiO2/Kaoline hybrid metal‐matrix composite prepared using high‐energy ball milling and sintering methods. In this study, phases related to the composite components are formed depending on the milling time, no undesirable phase is formed, but the peak intensities decreas as the milling time increases. Particle size increases from 63 to 215 μm with increasing milling time. Increasing the kaoline reinforcement ratio and sintering temperature increases the microhardness from 62.27 ± 2 to 75.83 ± 2 HV, and reduces the friction coefficient from 0.82 ± 0.01 to 0.62 ± 0.01. The wear rate of the composite without kaoline addition is 2.1 (mm3 m−1) × 10−3, while with 6 wt% kaoline addition, it decreases to 1.5 (mm3 m−1) × 10−3. There are no cracks in the composite other than plastic deformation due to sintering and wear. Peaks indicating endothermic and exothermic reactions during continuous heating occurr in the 635–750 °C temperature range.

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Effects of hydroxyapatite content on cytotoxicity, bioactivity and strength of metakaolin/hydroxyapatite composites

Twinprai,

Sutthi,

Ngaonee

et al. 2024

Arabian Journal of Chemistry

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Significance of the formation of pentahedral aluminum in the reactivity of calcined kaolin/metakaolin and its applications

Cited by 13 publications

References 101 publications

Preparation of Geopolymeric Materials from Industrial Kaolins, with Variable Kaolinite Content and Alkali Silicates Precursors

Preparation of Geopolymeric Materials from Industrial Kaolins, with Variable Kaolinite Content and Alkali Silicates Precursors

Investigation of Microhardness, Microstructural, Tribological, and Thermal Properties of Al7075/TiO₂/Kaoline Hybrid Metal Matrix Composites Produced by Powder Metallurgy Process

Effects of hydroxyapatite content on cytotoxicity, bioactivity and strength of metakaolin/hydroxyapatite composites

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Significance of the formation of pentahedral aluminum in the reactivity of calcined kaolin/metakaolin and its applications

Cited by 13 publications

References 101 publications

Preparation of Geopolymeric Materials from Industrial Kaolins, with Variable Kaolinite Content and Alkali Silicates Precursors

Preparation of Geopolymeric Materials from Industrial Kaolins, with Variable Kaolinite Content and Alkali Silicates Precursors

Investigation of Microhardness, Microstructural, Tribological, and Thermal Properties of Al7075/TiO2/Kaoline Hybrid Metal Matrix Composites Produced by Powder Metallurgy Process

Effects of hydroxyapatite content on cytotoxicity, bioactivity and strength of metakaolin/hydroxyapatite composites

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Investigation of Microhardness, Microstructural, Tribological, and Thermal Properties of Al7075/TiO₂/Kaoline Hybrid Metal Matrix Composites Produced by Powder Metallurgy Process