Crystallization mechanism of glass-ceramics prepared from Ni–Cu–Co mining wastes

The presence of minor elements on the crystallization kinetics of iron-rich glass obtained from a Ni–Cu–Co mining waste has been investigated. Two glasses named WG2 and RG were melted at 1500 °C. WG2 was prepared by using the mining waste, whereas RG contains pure oxides and no minor elements. WG2 and RG glasses presented high tendency toward crystallization with KH coefficients of 0.21 and 0.29, respectively. Due to the presence of minor elements WG2 crystallizes at lower temperatures than RG glass leading to an increase in the viscosity. Crystallization kinetics analyzed by different models gives activation energy values close to 500 and 400 kJ·mol− 1 for WG2 and RG, respectively. The Avrami parameter, n, depends on the particle size used for measurement and indicates the high tendency toward surface crystallization for both glasses.