Tagebuch des fondamentaux de l'énergie renouvelable et des applications
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ISSN: 2090-4541
ISSN: 2090-4541
MKh Rumi, MA Zufarov, EP Mansurovа and NA Kulagina
The results on crystallization of glasses of the cordierite composition, synthesized under the influence of concentrated radiant flux of different densities, are presented. Synthesis was carried out using a solar furnace or a solar simulator, wherein Xenon lamps of 10 kW power serve as a heat source. We studied glasses of the following stoichiometric composition 2MgO: 2Al2O3: 5SiO2 without a catalyst and with TiO2 as a catalyst. The initial raw materials were MgO, Al2O3 and quartz-kaolinite-pyrophyllite rock as a main source of SiO2. The natures of phase transitions in the samples obtained are studied using the X-ray analysis (DRON-UM-1) and the differential-thermal method (Derivatograph Q-1500 D). The absorption spectra are obtained on spectrophotometer SF-56. A comparison of the phase composition of the crystallized samples shows that the crystallization of μ-cordierite and the transition of μ-cordierite to α-cordierite in glasses, synthesized using a Xenon lamp, occurs at lower temperatures than those synthesized using solar radiation, provided the same conditions of synthesis and annealing. Besides of this, in glasses containing TiO2, the content of Ti3+ increases, and a decay of the concomitant phase, magnesium-aluminum-titanate, is activated at annealing temperatures above 1200°C. The differences in the character of the phase formation affect the activity of glass powders to sintering.
It is found that peculiarities of the spectral composition of a Xenon lamp and the Sun affect the nature of the glass crystallization process. A presence of a significant proportion of extreme ultraviolet radiation initiates the crystallization process by the photo-activation mechanism and has the same effect as a rise of the glass crystallization temperature or an increase of the catalyst concentration.