2021 Volume 61 Issue 12 Pages 2944-2952
In this work, the softening and melting (S&M) behaviour and whole blast furnace (BF) performance of Newman Blend Lump (NBLL), plant sinter, and sinter-NBLL mixture were studied using S&M under load test and numerical BF modelling. Both physical and chemical interactions between sinter and lump were confirmed in the S&M process. Significant improvements were found in the S&M behaviour of the sinter-NBLL mixture because of the physical and chemical interaction. The physical interaction was examined using X-ray/Neutron Computed Tomography (CT) scanning on the samples from interrupted S&M under load tests. The void fraction in the ferrous layer of the sinter-NBLL mixture was found to be similar to the sinter and was higher than that for NBLL. The chemical interaction was investigated by analysing the Ca transfer from sinter to NBLL, which indicated that Ca transfer started around 1200°C in the S&M process. FactSage was used to assist in the interpretation of the S&M test results. It was found that the NBLL sample starts to melt at a lower temperature compared to other burdens used in the present study, which also agreed well with the CT scan results. The whole BF performance of different ferrous burdens was studied using the experimental results as inputs. The sinter-NBLL mixture behaved more like the sinter than the NBLL; compared with the sinter only burden with the same total basicity, the sinter-NBLL combination formed a more permeable CZ, had a lower total BF pressure drop, and a higher gas utilization rate.