Mechanism of dehydroxylation temperature decrease and high temperature phase transition of coal-bearing strata kaolinite intercalated by potassium acetate

Cheng, Hongfei, Liu, Qinfu, Cui, Xiaonan, Zhang, Qian, Zhang, Zhiliang, & Frost, Ray L. (2012) Mechanism of dehydroxylation temperature decrease and high temperature phase transition of coal-bearing strata kaolinite intercalated by potassium acetate. Journal of Colloid and Interface Science, 376(1), pp. 47-56.

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The thermal decomposition and dehydroxylation process of coal-bearing strata kaolinite–potassium acetate intercalation complex (CSKK) has been studied using X-ray diffraction (XRD), infrared spectroscopy (IR), thermal analysis, mass spectrometric analysis and infrared emission spectroscopy. The XRD results showed that the potassium acetate (KAc) have been successfully intercalated into coal-bearing strata kaolinite with an obvious basal distance increase of the first basal peak, and the positive correlation was found between the concentration of intercalation regent KAc and the degree of intercalation. As the temperature of the system is raised, the formation of KHCO3, KCO3 and KAlSiO4, which is derived from the thermal decomposition or phase transition of CSKK, is observed in sequence. The IR results showed that new bands appeared, the position and intensities shift can also be found when the concentration of intercalation agent is raised. The thermal analysis and mass spectrometric analysis results revealed that CSKK is stable below 300 °C, and the thermal decomposition products (H2O and CO2) were further proved by the mass spectrometric analysis. A comparison of thermal analysis results of original coal-bearing strata kaolinite and its intercalation complex gives new discovery that not only a new mass loss peak is observed at 285 °C, but also the temperature of dehydroxylation and dehydration of coal bearing strata kaolinite is decreased about 100 °C. This is explained on the basis of the interlayer space of the kaolinite increased obviously after being intercalated by KAc, which led to the interlayer hydrogen bonds weakened, enables the dehydroxylation from kaolinite surface more easily. Furthermore, the possible structural model for CSKK has been proposed, with further analysis required in order to prove the most possible structures.

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ID Code: 58048
Item Type: Journal Article
Refereed: Yes
Keywords: Coal-bearing strata kaolinite, Potassium acetate, Intercalation complex, Dehydroxylation, Structural model
DOI: 10.1016/j.jcis.2012.02.065
ISSN: 0021-9797
Subjects: Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > PHYSICAL CHEMISTRY (INCL. STRUCTURAL) (030600) > Structural Chemistry and Spectroscopy (030606)
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2012 Elsevier Inc. All rights reserved.
Copyright Statement: This is the author’s version of a work that was accepted for publication in Journal of Colloid and Interface Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Colloid and Interface Science, [VOL 376, ISSUE 1, (2012)] DOI: 10.1016/j.jcis.2012.02.065
Deposited On: 13 Mar 2013 02:00
Last Modified: 13 Mar 2013 20:53

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