To evaluate the suitable sinter properties and desirable measures for blending flux in blast furnace burdens under the high-rate pulverized coal injecting operation, the off-line model experiments, actual sinter production and actual blast furnace operation have been carried out. Main results obtained are summarized as follows:
1. Sinter with low slag content was produced by reducing fluxes having SiO2-MgO and CaO components in sinter raw mixture, and lump fluxes were charged from the top or fine flux was injected through the tuyere in blast furnace to maintain the tapped slag compositions. By application of this measures, permeability in the lower part of blast furnace was improved. The test results showed that the fine flux injection is the most effective in comparison with other measures.
2. According to the hot model trial, the top charged or tuyere injected fluxes were almost slagged at the boundary of raceway.
3. Sinter with low SiO2-low MgO content produced at Muroran No. 6 sintering machine has a high reducibility in the lumpy zone due to the increase of hematite and has a good permeability in the cohesive zone due to the decrease of FeO contained melt in blast furnace.
