Investigation of the Testing Method of Softening–Melting Properties of Iron-Bearing Materials

The softening–melting properties of iron-bearing materials play a crucial role in the reduction process in the lumpy zone in the blast furnace (BF) and affect the height, thickness, and shape of the cohesive zone, as well as gas permeability in the BF. A novel softening–melting method was developed based on actual BF production practices, which consistently matches the reduction index and metallization degree observed in actual BF operations compared to the conventional methods. Under the novel softening–melting testing method, the characteristic temperatures (T40 and TS) increase by about 5 °C and 49 °C, respectively, compared to the conventional method. Additionally, the permeability index (S) of the sinter in the novel method is about 707 kPa·°C lower compared to the conventional method. Clearly, the novel method results in higher softening–melting characteristic temperatures for iron-bearing materials compared to the traditional method, more closely matching actual BF conditions. This approach can provide valuable insights for improving gas permeability and enhancing the reduction process of iron-bearing materials in the BF.