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

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 50.80 ± 1.12% and 85.80 ± 0.61%, respectively. Finally, average activation energies (conversion values (α) 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.

Magnesium Borates: The Relationship between the Characteristics, Properties, and Novel Technologies

“…"Asymmetric stretching of B (4) -O" can be explained with the peaks in the range of 1200-950 cm À1 . The peaks at the lower wavelength values of 750 cm À1 can be interpreted with the "bending of B (3) -O" [6][7][8]. In Raman analyses of magnesium borates, the characteristic peaks are seen in the wavelength region of 1200-250 cm À1 .…”

“…For the hydrated forms of magnesium borates, the stretching for polyanion of [B 6 O 7 (OH) 6 ] À2 and [B 3 O 3 (OH) 4 ] À2 is seen between 750 and 620 cm À1 . The "bending of B (3) -O" and "bending of B (4) -O" can be seen in the Raman shift wavelength ranges of 620-500 cm À1 and 500-250 cm À1 , respectively [6,7,9].…”

Effect of Capping Agents on the Nanoscale Metal Borate Synthesis

“…Water is selected as the solution medium in liquid-state conditions; however, other types of fuels could also be used in metal borate preparation. The liquid-state synthesis procedure could also be entitled as hydrothermal, combustion, and co-precipitation methods [42][43][44]. The capping agent is usually added to the mixture of the dissolved sources.…”

Microwave Dehydration Behaviour of Inderite and Comparison with Thermal Analyses Methods

“…The second step is called dehydroxilation which is removal hydroxyl groups on a compound as water molecules. Dehydration behaviors for different kinds of metal borates were studied in literature; and the thermal parameters were calculated [5,6].…”