Influence of Fe2O3 and Atmosphere on Crystallization Characteristics of Synthetic Coal Slags

Crystallization in the molten slag of entrained-flow coal gasifiers can increase its viscosity and affect the flow of the slag layer along the wall. The chemical composition of the slag plays an important role in crystallization behavior and crystal characteristics. The aim of the work reported here is to study the influence of Fe2O3 on crystallization tendency. Six synthetic slags with different Fe2O3 concentrations, ranging from 5 to 30 wt %, were investigated using differential scanning calorimetry (DSC) and the single hot thermocouple technique (SHTT). In addition, three of the slags were reduced in a 60:40 CO/CO2 atmosphere, and their crystallization characteristics were compared to the original slags. The time–temperature–transformation (TTT) diagrams for each slag were constructed. The Kissinger method was used to calculate the activation energy based on DSC results under cooling conditions, and the Johnson–Mehl–Avrami (JMA) equation was applied to calculate crystallization mechanisms under isother...