Influence of the particle-size reduction by ultrasound treatment on the dehydroxylation process of kaolinites
- 101 Downloads
- 11 Citations
Abstract
Kaolinites from well-known sources (KGa-1 and KGa-2) were used to study the influence of the particle-size reduction on the dehydroxylation process. Size reduction of particles was obtained by ultrasound treatment to avoid the effect of the progressive amorphization of the structure, which takes place with the traditional grinding treatment.
The particle-size reduction causes an increase of the mass loss between 140 and 390°C attributed to the loss of the hydroxyl groups exposed on the external surface of kaolinite; a shift to lower temperatures of the endothermic effect related with the mass loss between 390 and 600°C and a shift of the end of dehydroxylation to lower temperatures. The first modification can be explained by an increase of the number of hydroxyls exposed on the external surface of kaolinite which is proportional to the new surface generated in the particle reduction process, whereas the shift of the dehydroxylation to lower temperatures is related to the reduction of the dimensions of the particles which favour the diffusion controlled mechanisms.
Comparing between the DTA curves to the TG curves of the studied samples shows that the observed modifications in the thermal properties induced by the particle-size reduction are greater for the low-defect kaolinite. The intensity of these modifications depends on the effectiveness of the ultrasound treatment.
Keywords
kaolinite mass loss particle-size reduction sonication structural disorder thermal analysisPreview
Unable to display preview. Download preview PDF.
References
- 1.H. H. Murray, Clay Miner., 33 (1999) 65.Google Scholar
- 2.H. H. Murray, Appl. Clay Sci., 17 (2000) 207.Google Scholar
- 3.B. T. Shaw, J. Phys. Chem., 46 (1942) 1032.Google Scholar
- 4.W. D. Laws and J. B. Page, Soil Sci., 62 (1945) 319.Google Scholar
- 5.R. D. Dragsdorf, H. E. Kissinger and A. T. Perkins, Soil Sci. Soc. Am., 71 (1951) 439.Google Scholar
- 6.T. Haase and K. Winter, Bull. Soc. Fr. Ceram., 44 (1959)13.Google Scholar
- 7.J. G. Miller and T. D. Oulton, Clays Clay Miner., 18 (1970) 313.Google Scholar
- 8.Z. Juhász, Acta Mineralogica-Petrographica [suppl.], 24 (1980) 121.Google Scholar
- 9.J. Kristóf, R. L. Frost, J. T. Kloprogge, E. Horváth and É. Makó, J. Therm. Anal. Cal., 69 (2002) 77.Google Scholar
- 10.P. J. Sánchez-Soto, M. C. Jiménez de Haro, L. A. Pé rez-Maqueda, I. Varona and J. L. Pérez-Rodríguez, J. Am. Ceram. Soc., 83 (2000) 1649.Google Scholar
- 11.L. A. Pérez-Maqueda, O. B. Caneo, J. P. Poyato and J. L. Pérez-Rodríguez, Phys. Chem. Minerals, 28 (2001) 61.Google Scholar
- 12.J. L. Pérez-Rodríguez, F. Carrera, J. P. Poyato and L. A. Pérez-Maqueda, Nanotechnology, 13 (2002) 382.Google Scholar
- 13.A. Pérez-Maqueda, F. Franco, M. A. Avilés, J. P. Poyato and J. L. Pérez-Rodríguez, Clays Clay Miner., (in press).Google Scholar
- 14.F. Franco, L. A. Pérez-Maqueda and J. L. Pérez-Rodríguez, Thermochim. Acta, 404 (2003) 71.Google Scholar
- 15.L. Heller-Kallai and I. Lapides, J. Therm. Anal. Cal., 71 (2003) 689.Google Scholar
- 16.F. Franco and M. D. Ruiz Cruz, J. Therm. Anal. Cal., 73 (2003) 151.Google Scholar
- 17.H. Van Olphen and J. J. Fripiat, Oxford, Pergamon 1979, p. 346.Google Scholar
- 18.S. J. Chipera and D. L. Bish, Clays Clay Miner., 49 (2001) 398.Google Scholar
- 19.S. Guggenheim and A. F. K. van Groos, Clays Clay Miner., 49 (2001) 433.Google Scholar
- 20.D. N. Hinckley, Clays Clay Miner., 11 (1963) 229.Google Scholar
- 21.B. D. Cullity, Diffraction 1: The directions of diffracted beams, In: Elements of X-ray diffraction, Addison-Wesley Publishing Co., Inc., USA 1956, 78.Google Scholar
- 22.F. Franco, L. A. Pérez-Maqueda and J. L. Pérez-Rodríguez, J. Colloids Interface Sci., (in press).Google Scholar
- 23.K. Okada, N. Otsuka and J. Ossaka, J. Am. Ceram. Soc., 69 (1986) 51.Google Scholar
- 24.B. Sonuparlak, M. Sarikaya and I. A. Aksay, J. Am. Ceram. Soc., 70 (1987) 837.Google Scholar
- 25.P. Dion, J. F. Alcover, F. Bergaya, A. Ortega, P. L. Llewellyn and F. Rouquerol, Clay Miner., 33 (1998) 269.Google Scholar
- 26.R. L. Frost and A. M. Vassallo, Clays Clay Miner., 44 (1996) 635.Google Scholar
- 27.O. Castelein, B. Soulestin, J. P. Bonnet and P. Blanchart, Ceram. Int., 27 (2001) 517.Google Scholar