Characteristics of steel slag under microwave heat treatment

The effects of microwave irradiation on the dissociation behavior and structural characteristics of steel slag were systematically investigated in this work. The microwave absorption characteristics of steel slag were studied by acquiring the heating curves of the RO phase, Fe3O4, Fe and gangue mineral components of this material. The selective heating characteristic of microwave irradiation accounted for the considerably different heating rates and saturation temperatures of the RO phase, Fe3O4, Fe, and gangue minerals under microwave heating. Scanning electron microscopy revealed that intergranular fractures formed between the RO phase and the matrix. The size and numbers of microcracks increased with increasing exposure time and microwave output power. Subsequent separation trials showed that the mineral liberation of the RO phase increased from 73.6 % to 80.6 % after microwave treatment. This work proved that microwave irradiation is an effective approach for removing the RO phase from steel slag. Moreover, this new technology would promote the application of steel slag in the cement industry by improving RO phase liberation.