Temperature Effect on the Solid-State Synthesis of Dehydrated Zinc Borates

Turkey has 72 % of total world boron reserves on the basis of B2O3.Borates that is a refined form of boron minerals have a wide range of applications. Zinc borates can be used as multifunctional synergistic additives. The most important properties are low solubility in water and high dehydration temperature. Zinc borates dehydrate above 290°C and anhydrous zinc borate has thermal resistance about 400°C. Zinc borates can be synthesized using several methods such as hydrothermal and solid-state processes. In this study, the solid-state method was applied between 500 and 800°C using the starting materials of ZnO and H3BO3 with 1:4 mole ratio. The reaction time was determined as 4 hours after some preliminary experiments. After the synthesis, the crystal structure and the morphology of the products were examined by XRay Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and Raman Spectrometer. As a result the form of ZnB4O7 was synthesized with the highest crystal score at 800°C.




References:
[1] D. G├╝rhan, G. ├û. ├çakal, ─░. Ero─ƒlu, and S. ├ûzkar, Kesikli reaktörde ├ºinko
borat ├╝retimini etkileyen parametrelerin incelenmesi, 1. National Boron
Workshop Symposium Book, April 28-29, Ankara, 2005.
[2] D. Schubert, F. Alam, M. Visi and C. Knobler, "Structural
characterization and chemistry of the industrially important zinc borate
Zn[B3O4(OH)3]", Chem. Mater., vol. 15, pp. 866-871, 2002.
[3] A. V. Shete, S. B. Sawant, and V. G. Pangarkar, "Kinetics of fluid-solid
reaction with an insoluble product: zinc borate by the reaction of boric
acid and zinc oxide", J. Chem. Technol. Biot., vol. 79, pp. 526-532,
2004.
[4] X. Shi, Y. Xiao, M. Li, L. Yuan, and J. Sun, "Synthesis of an
industrially important zinc borate, 2ZnO┬À3B2O3┬À3H2O, by a rheological
phase reaction method" Powder Technol., vol. 186, pp. 263-266, 2008.
[5] X. Shi, M. Li, H. Yang, S. Chen, L. Yuan, K. Zhang, and J. Sun, "PEG-
300 assisted hydrothermal synthesis of 4ZnO.B2O3.H2O nanorods",
Mater. Res. Bull., vol.. 42, pp. 1644-1649, 2007.
[6] H. Igarashi, H. Sawada, A. Tatebe, and K. Sakao, Patent No: 6780913,
U.S.A., 2002.