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The Scientific World Journal
Volume 2014, Article ID 985185, 10 pages
http://dx.doi.org/10.1155/2014/985185
Research Article

Characterization and Thermal Dehydration Kinetics of Highly Crystalline Mcallisterite, Synthesized at Low Temperatures

Department of Chemical Engineering, Yildiz Technical University, 34210 Istanbul, Turkey

Received 18 November 2013; Accepted 19 January 2014; Published 25 February 2014

Academic Editors: A. L. R. Mercê and E. Mikuli

Copyright © 2014 Emek Moroydor Derun and Fatma Tugce Senberber. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The hydrothermal synthesis of a mcallisterite (Mg2(B6O7(OH)6)2 9(H2O)) mineral at low temperatures was characterized. For this purpose, several reaction temperatures (0–70°C) and reaction times (30–240 min) were studied. Synthesized minerals were subjected to X-ray diffraction (XRD), fourier transform infrared (FT-IR), and Raman spectroscopies and scanning electron microscopy (SEM). Additionally, experimental analyses of boron trioxide (B2O3) content and reaction yields were performed. Furthermore, thermal gravimetry and differential thermal analysis (TG/DTA) were used for the determination of thermal dehydration kinetics. According to the XRD results, mcallisterite, which has a powder diffraction file (pdf) number of “01-070-1902,” was formed under certain reaction parameters. Pure crystalline mcallisterite had diagnostic FT-IR and Raman vibration peaks and according to the SEM analysis, for the minerals which were synthesized at 60°C and 30 min of reaction time, particle size was between 398.30 and 700.06 nm. Its B2O3 content and reaction yield were % and %, respectively. Finally, average activation energies (conversion values that were selected between 0.1 and 0.6) were calculated as 100.40 kJ/mol and 98.31 kJ/mol according to Ozawa and Kissinger-Akahira-Sunose (KAS) methods, respectively.