Kinetics Study on Controlled Crystallization of a Ca₂ZnSi₂O₇ Phase in Materials Obtained from Vitrification of Metallurgical Slag and Recycled Soda Lime Glass

Abstract:

Non isothermal kinetics of a glass obtained from a mixture of 59 wt % of metallurgical slag and 41 wt % of soda lime recycled glass was studied by differential thermal analysis (DTA), x-ray diffraction (XRD) and scanning electron microscopy (SEM). The curves of differential thermal analysis revealed the presence of two exothermic peaks, a major peak at 810 °C and a minor peak at 1085 °C. DRX revealed that the first exothermic peak corresponds to the formation of hardystonite, Ca₂ZnSi₂O₇ and aegirine, NaFe³⁺Si₂O₆, while the second minor peak corresponds to the formation of zinc ferrite, ZnFe₂O₄. The activation energy of the crystallization, E_a, was calculated with the Kissinger equation from DTA data, obtained at different heating rates. In addition, the particle size effect on the kinetics of crystallization was studied. The Avrami factor, n, was calculated with Augis-Bennett method. The values of obtained E_a increase with bigger particle sizes and also the value of n, indicating that for small particles the superficial crystallization mechanism is predominant, while bulk mechanism is preferential on large particles. Obtained materials are suitable for some structural applications.

• Periodical: Advances in Science and Technology (Volume 68)
• Pages: 114-119
• DOI: https://doi.org/10.4028/www.scientific.net/AST.68.114
• Online since: October 2010
• Authors: Erika Iveth Cedillo González, Juan Jacobo Ruiz Valdés, Anabel Álvarez Méndez
• Keywords: Hardystonite, Metallurgical Slag, Non Isothermal Kinetic

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