The Effect of Thermal and Mechanical Treatments on Kaolinite: Characterization by XPS and IEP Measurements

Sánchez, Rosa M. Torres; Basaldella, Elena Isabel; Marco, José F.

doi:10.1006/jcis.1999.6241

Cited by 70 publications

(18 citation statements)

References 21 publications

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“…-At 980°C, the exothermic peak without any weight loss has been attributed to various phenomena: formation of a spineltype phase and/or germination of mullite [22], evolution of aluminum coordinance toward VI [23], extraction of amorphous silica from metakaolinite and germination of mullite [24], or separation into a silica-rich and an alumina-rich domains [25]. Fig.…”

Section: Thermal Characterizationmentioning

confidence: 99%

Comparison of surface properties between kaolin and metakaolin in concentrated lime solutions

Konan

Peyratout

Smith

et al. 2009

Journal of Colloid and Interface Science

112

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Section: Thermal Characterizationmentioning

confidence: 99%

Comparison of surface properties between kaolin and metakaolin in concentrated lime solutions

Konan

Peyratout

Smith

et al. 2009

Journal of Colloid and Interface Science

112

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“…This indicates that the halloysite phase is more ordered in the acid-treated materials, and the high content in octahedral Al of halloysite makes it, especially resistant to acid attack [24]. When halloysite sample (Hal) was calcined at 600˚C for 2 h (HalC) dehydration occurred, the peaks of halloysite disappeared, and little amount of an amorphous phase, that some authors ascribe to an amorphous phase of SiO 2 [25], began to separate as evidenced by the presence of a very broad band between 2θ = 10˚-40˚. Heating halloysite above 550˚C transforms it into metakaolin (HalC) by the effect of the loss of structural OH groups and a rearrangement in Si and Al atoms leading to a decrease in octahedral Al and the appearance of penta-and tetra-coordinated Al [26].…”

Section: Characterization Of Materialsmentioning

confidence: 93%

Trichlorophenol removal from aqueous solutions by modified halloysite: kinetic and equilibrium studies

Sahnoun

Boutahala

Zaghouane-Boudiaf

et al. 2016

Desalination and Water Treatment

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A B S T R A C TTo obtain new materials, we modified Algerian halloysite by thermal activation (HalC), acid activation (HalA), combined thermal-acid activation (HalCA) and acid-thermal activation. X-ray diffraction, Fourier Transform infrared and BET textural analysis were used to characterize changes. After the HalC of halloysite at 600˚C, no XRD peaks were shown and a total disappearance of the absorption bands ranging from 3,700 to 3,600 cm −1 . The treatment of halloysite by sulphuric acid increases the surface area from 185.4 to 321.0 m 2 /g. Halloysite is first calcined and then activated by acid, its surface area increases from 74.3 to 538.6 m 2 /g. The effect of initial pH, adsorbent dose, contact time and temperature on the removal of 2,4,5-trichlorophenol (TCP) by modified halloysite samples was investigated. Equilibrium data were fitted to the Langmuir, Freundlich and Toth models. The best fit of the cited models was the Freundlich model, which suggested infinite adsorption onto heterogeneous surface. The pseudo-first-order, pseudo-second-order and intraparticle diffusion models were applied to the experimental kinetic data. The results showed that the pseudo-second-order is the best model to describe the process. The study of thermodynamic parameters shows that the process of adsorption of TCP onto the prepared samples was spontaneous, endothermic and physical in nature.

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“…Calcined products shown very clear weak diffraction peaks at 2θ = 27.39 resulted from rutile at 800 °C indicating the transformation of the anatase crystal structure. The mullite were observed from the XRD patterns of calcined products at 900 °C and 1000 °C, which implied the recrystallization of the metakaolinite [13]. Compared with all XRD patterns, the degree of disorder of the calcined products was highest at 800 °C which might have high pozzolanic activity.…”

Section: Fig 1 Dta-tg Curves Of Waste Kaolinmentioning

confidence: 94%

Preliminary Investigation of Pozzolanic Properties of Calcined Waste Kaolin

Huang¹,

Deng²,

Wang³

et al. 2018

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Current research aims to investigate the influence of calcination temperature on the pozzolanic activity of the waste kaolin and the impact of calcination products on Portland cement hydration. The raw material with approximately 85 % kaolinite was calcined to temperatures ranging between 500 and 1000 °C. The clay and its calcined products were characterized by TGA-DTA, SEM-EDS, XRD, FT-IR and BET. The pozzolanic activity of the calcined products was assessed by electrical conductivity test and compressive strength in mortars with 30 % substitution of Portland cement. The effect of calcined products on Portland cement hydration was characterized by XRD and SEM. The results showed that the calcination temperature had an important influence on mineral phase transition and the pozzolanic activity of calcined products. The degree of disorder and pozzolanic activity of calcined products at 800 °C was the highest at temperatures ranging from 500 and 1000 °C. The impact of calcined products on the hydration of blended systems was a combination of a filler effect at early ages and the pozzolanic reaction at later. The experimental results indicated that calcined products of waste kaolin constituted a potential source of high reactivity pozzolanic materials.

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The Effect of Thermal and Mechanical Treatments on Kaolinite: Characterization by XPS and IEP Measurements

Cited by 70 publications

References 21 publications

Comparison of surface properties between kaolin and metakaolin in concentrated lime solutions

Comparison of surface properties between kaolin and metakaolin in concentrated lime solutions

Trichlorophenol removal from aqueous solutions by modified halloysite: kinetic and equilibrium studies

Preliminary Investigation of Pozzolanic Properties of Calcined Waste Kaolin

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