China's Refractories

Abstract: Three different kinds of corundum aggregates—tabular sintered alumina, dense sintered alumina, and fused dense corundum—were introduced into the silica fume free or silica fume containing Al₂O₃-SiC-C iron runner castables to investigate their influences on the flow ability, linear change on heating, bulk density, apparent porosity, cold strength, hot modulus of rupture, thermal shock resistance, slag resistance, oxidation resistance as well as wear resistance of Al₂O₃-SiC-C iron runner castables. The results show that (1) compared with the specimens with fused dense corundum, the specimens with dense sintered alumina have equivalent installation property, slag resistance and oxidation resistance, equivalent or even higher cold modulus of rupture, cold crushing strength and hot modulus of rupture, exhibiting better thermal shock resistance and cold wear resistance; (2) adopting bimodal alumina micropowder LISAL22RABL as well as water reducers ZX2 and ZD2 can well reduce the water requirement of silica fume free castables, solving the problem of deteriorated flow ability resulted from the lack of silica fume; since the lack of silica fume avoids the formation of low melting point liquid, the hot modulus of rupture and the thermal shock resistance of the silica fume free castables are both better than those of the silica fume containing castables; (3) the density of the castable specimens with dense sintered alumina is 4%-6% lower than that of the castable specimens with fused dense corundum so the refractories consumption of one iron runner reduces by 5% by using the castable with dense sintered alumina, which obviously reduces the cost of refractories. 

Key words: alumina-silicon carbide-carbon castables for iron runner, tabular sintered alumina, dense sintered alumina, fused dense corundum