Calcination Condition of Dolomite‐Based Materials Influencing Static Dissolution in Synthetic Electric Arc Furnace Slag

The addition of basic additives in steelmaking processes is essential because these lead to slag adaptation and enable refining reactions. In calcination treatment, the process parameters temperature and dwell time influence the decomposition of dolomite as a magnesium-containing lime substitute. It results in specific properties such as varying residual fractions of carbonates CaCO3 center dot MgCO3 and porosity. The properties affect the dissolution kinetics, and the fast and complete dissolution is of interest. Hence, the static high-temperature dissolution tests using dolomite-based samples in diverse conditions (raw, modified, soft-burnt, and hard-burnt) are executed to determine the impact of the calcination state. The specimens are immersed in synthetic electric arc furnace slag, including 10 wt% Al2O3, 25 wt% SiO2, 25 wt% CaO, 8 wt% MnO, and 32 wt% FeO. The dolomite or dolime dissolves in the stagnant oxidic melt within the reaction time of 10 min at 1450 degrees C. The resulting chemistries of quenched slags, representing the current dissolution status, are examined by scanning electron microscopy using energy-dispersive X-ray spectroscopy analysis on metallographically prepared cross-sections and via X-ray fluorescence analysis of mechanically extracted slag fractions. The dissolution performance is characterized and compared for the different additive materials.