Thermodynamics and Kinetics on Hot State Modification of BOF Slag by Adding SiO2

摘要

The application of BOF slag in the field of building materials is limited by its volume expansion during natural aging, which is mainly attributed to the hydration reaction of free calcium oxide in slag. In this study, the influence of SiO2 addition and atmosphere on the mineral modification of typical industrial converter slag, as well as, the dissolution kinetics of SiO2 in slag were explored. The results show that added SiO2 reacts with the free calcium oxide in slag to form dicalcium silicate. Ferrous oxide is oxidized to iron oxide under air atmosphere, which combines with free calcium oxide to form calcium aluminoferrite. Therefore, the amount of SiO2 required for complete digestion of free calcium oxide under air atmosphere is less than that under argon atmosphere. Based on the results of the immersion experiments of quartz rods, the dissolution model of spherical quartz sand was developed, which can be used to predict dissolution curves of quartz sand with different particle sizes in converter slag. The corrosion of magnesia crucible contacted with the molten slag in air atmosphere is more serious than argon atmosphere, which should attract more attentions.

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