Crystallization kinetics of glass prepared with foundry slag

Abstract

Iron foundry slag and hydrated lime were used in glass preparation by the melt-quenching method. The glass obtained was heat-treated using the thermal analysis technique. A crystallization kinetics study was carried out with glass powder samples using a non-isothermal method at five different heating rates by differential scanning calorimetry (DSC). Considering that few studies compare kinetic results obtained by different methods, in this work, the activation energy (E_a) of the crystallization process was obtained using the Kissinger and Augis-Bennett models for comparison purposes. The E_a results showed negligible variation in comparing the methods used, nevertheless, linear fitting of crystallization peaks was slightly better by the Augis-Bennett than the Kissinger model. The Avrami index values showed an increasing nucleation rate for two stable phases and decreasing for the metastable phase present in the glass-ceramic. Avrami indexes obtained also indicated an interface-controlled particle growth, whose scanning electron microscopy images showed different morphologies of crystalline particles in the bulk of the glass matrix.

Keywords:
slag; glass; glass-ceramic; crystallization; kinetics