The experiments were conducted under a simulated blast furnace condition to study the effect of material composition on softening and melting properties of the burden materials. In was found that the sinter produced at China Steel Corporation possessed a high softening temperature (around 1400 ℃) but a relatively low meltdown ratio and poor high temperature permeability. The decrease in basicity (CaO/SiO_2) and increase in Al_2O_3 content favoured the high temperature permeability of the sinter. In general, the lump ore and the commercial acid pellet had imperfections in low softening temperature and large gas flow resistance during the softening and melting stage. These imperfections could be overcome by adding a small amount of small-size coke (e.g. 3%). Mixing of ferrous burdens (sinter, pellet, lump ore) was also one of the effective ways to improve the softening and melting properties. It was observed that the mixtures containing 60% to 80% sinter, 0% to 20% acid pellet and 20% lump ore exhibited much better properties than the individual sinter, acid pellet or lump ore. Small-size iron ore and sinter generated the specific problems in softening and melting properties, respectively. Several mixing patterns could also eliminate the problems and present satisfactory softening and melting properties.
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