Non-isothermal Decomposition Kinetics of Gibbsitic Bauxite from Thermogravimetric Data

Ray, D.; Parya, T. K.
May 2013
Interceram: International Ceramic Review;May/Jun2013, Vol. 62 Issue 2, p120
Trade Publication
A comprehensive study to determine the thermal decomposition kinetics of naturally occurring high aluminous bauxite rock with variation of heating rate is of absolute necessity to better understand the underlying mechanism so that the course of the reaction, optimization of process conditions, and the nature of the end product can be carefully controlled. The kinetics of thermal decomposition of gibbsitic bauxite were studied by thermogravimetric analysis (TG) in static air using different heating rates (5.0, 7.5 and 10.0 K・min–1) under non-isothermal conditions. The isoconversional Flynn-Wall-Ozawa and model free Kissinger methods were applied to determine the kinetic activation energy and pre-exponential factor parameters of the decomposition process. The bauxite decomposed by two steps. The 1st step consisted of transformation through a dehydration process from bauxite to boehmite in the temperature range 275–350 °C. This was followed by a 2nd step conversion into pseudo boehmite or metastable transition alumina through removal of structural water from the boehmite crystal lattice in the temperature range 450–550 °C. The average activation energy computed by both methods was found to be well consistent with values from other reference sources. Finally, the Malek method was employed to elucidate appropriate model expression for the thermal decomposition mechanism of the bauxite.


Related Articles

  • Low Temperature Synthesis of Hexagonal Shaped α-Al2O3 Using a Solvothermal Method. A-Young Kim; Hyun Soo Kim; No-Kuk Park; Tae Jin Lee; Won Gun Lee; Heun Duk Kim; Jun Woo Park; Misook Kang // Journal of Nanomaterials;2012, p1 

    This study demonstrates the low temperature synthesis of αAl2O3 by solvothermal method using gibbsite alumina precursor in 1, 4-butanediol solvent according to various pH conditions. In acidic solution, an orthorhombic boehmite (AlOOH) structure was obtained after solvothermal reaction. A...

  • Novel Synthesis Method of Alumina Having a Large Pore-Volume. Sung-Wook Kim; Iwamoto, Shinji; Inoue, Masashi // Topics in Catalysis;Jun2010, Vol. 53 Issue 7-10, p535 

    The reaction of alumina isopropoxide (AIP) in straight-chain primary alcohols at high temperatures yields the alkyl derivatives of boehmite. Crystallinity of the alkyl derivatives of boehmite can be controlled by the feed ratio of AIP/alcohol. The alumina samples derived from the products having...

  • Analysis of Mechanically Induced Reactivity of Boehmite Using Kinetics of Boehmite to γ-AlO Transformation. Alex, T.; Sasi Kumar, C.; Kailath, Ansu; Kumar, Rakesh; Roy, S.; Mehrotra, S. // Metallurgical & Materials Transactions. Part B;Jun2011, Vol. 42 Issue 3, p592 

    This article focuses on the mechanically induced reactivity of boehmite prepared by thermal decomposition of gibbsite. Boehmite, which retained the morphology of gibbsite, was characterized by a specific surface area of 264 m/g. Mechanical activation (MA) was carried out in a planetary mill up...

  • Kinetics and Mechanism of Non-Isothermal Decomposition of Ca(II)-, Sr(II)- and Ba (II)- Cross-Linked Divalent Metal-Alginate Complexes. Zaafarany, Ishaq; Khairou, Khalid; Tirkistani, Fahd; Iqbal, Sayed; Khairy, Mohamed; Hassan, Refat // International Journal of Chemistry;Dec2012, Vol. 4 Issue 6, p7 

    The kinetics of thermal decomposition of Ca(II)-, Sr(II)- and Ba(II)- cross-linked metal-alginate biopolymeric complexes as biocatalysts have been studied using thermogravimetric (TG) and differential thermogravimetric (DTG) techniques in static air. The TG curves showed three stages of weight...

  • Thermal and kinetic analysis of uranium salts. Çılgı, Gülbanu; Cetişli, Halil; Donat, Ramazan // Journal of Thermal Analysis & Calorimetry;Feb2014, Vol. 115 Issue 2, p2007 

    Thermal decomposition of U(CO)·6HO was studied using TG method in nitrogen, air, and oxygen atmospheres. The decomposition proceeded in five stages. The first three stages were dehydration reactions and corresponded to removal of four, one, and one mole water, respectively. Anhydrous salt...

  • Thermal and spectroscopic studies of solid oxamate of light trivalent lanthanides. Caires, F.; Lima, L.; Gomes, D.; Gigante, A.; Treu-Filho, O.; Ionashiro, M. // Journal of Thermal Analysis & Calorimetry;Jan2013, Vol. 111 Issue 1, p349 

    Solid-state LnL·1.25HO compounds, where L is oxamate and Ln is light trivalent lanthanides, have been synthesized. Simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), experimental and theoretical infrared spectroscopy, TG-DSC coupled to FTIR, elemental analysis,...

  • Synthesis of γ-AlO nanowires through a boehmite precursor route. YANG, QI // Bulletin of Materials Science;Apr2011, Vol. 34 Issue 2, p239 

    Crystalline γ-AlO nanowires with diameter, 20-40 nm, length above 600 nm and aspect ratio above 30 have been successfully synthesized by thermal decomposition of boehmite ( γ-AlOOH) precursors obtained via hydrothermal route by using AlCl, NaOH and NH as starting materials....

  • Increase in Thermo-Stability of Chromia-Alumina Catalysts Used in Dehydrogenation of Paraffines by Means SHF Radiation. Khasanovich Karimov, Oleg; Rifovich Daminev, Rustem; Zainullovna Kasyanova, Liliya // Middle East Journal of Scientific Research;2013, Vol. 18 Issue 2, p127 

    The article investigates influence of microwave radiation thermo-stability of chromia-alumina catalysts used in the processes of de-hydrating of lowest paraffines. It was discovered that use of SHF radiation for manufacturing catalysts allows to increase thermo-stability. Increase in...

  • Carbon Nanotubes Synthesis by Catalytic Decomposition of Ethyne Using Fe/Ni Catalyst on Aluminium Oxide Support. Dikio, Ezekiel Dixon; Bixa, Nolukhanyo // International Journal of Applied Chemistry;2011, Vol. 7 Issue 1, p35 

    Carbon nanotubes were synthesized by catalytic chemical vapour deposition (CCVD) over Iron and Nickel mixed catalysts on aluminium oxide support. The catalyst was synthesized by co-precipitation from Fe-Ni nitrates. Raman spectroscopy, scanning electron microscopy and transmission electron...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics