Crystallization behavior of amorphous slag beads prepared by gas quenching of blast furnace slag

Slag beads with different amorphous phase contents can be prepared by gas quenching of blast furnace slag (BFS). The amorphous phase content can affect the activity of these slag beads, with higher amorphous phase contents leading to higher activity. In this study, thermodynamic simulations with FactSage 7.1 and differential scanning calorimetry were used to investigate the crystallization behavior of BFS during continuous cooling. The influence of different cooling rates and basicities on the crystallization behavior of BFS was studied, and the activation energy for crystallization was calculated by the Kissinger and Ozawa methods. The results showed that the precipitation of crystals could be prevented at high cooling rates and low BFS basicity. Accordingly, no precipitation of BFS crystals was observed when basicity was less than 0.91 and the cooling rate was above 50 °C/min. In addition, the activation energy for crystallization of BFS decreased with increasing basicity