电熔镁砂加入量对Al_2O_3-SiC-C浇注料性能的影响

Effects of fused magnesite on properties of Al_2O_3-SiC-C castables

以电熔棕刚玉颗粒（粒度为5～3mm、3～1mm，≤1mm）、电熔白刚玉细粉（≤0．088mm）、SiC颗粒（≤1mm）和细粉（≤O．088mm）、电熔镁砂细粉（≤0．088mm）、活性α-Al2O3微粉、SiO2微粉、Si粉和球状沥青为主要原料，以纯铝酸钙水泥为结合剂，配制成电熔镁砂细粉加入量（质量分数）分别为0、3％、6％、9％、12％的出铁沟用Al2O3-SiC-C浇注料，经振动成型、养护、脱模、100℃24h烘干后，分别于1100℃3h、1450℃3h热处理，测定处理后试样的体积密度、显气孔率、烧后线变化率、抗折强度、抗高炉渣侵蚀性和抗氧化性，并分析其物相组成和显微结构。结果表明：随着电熔镁砂加入量的增加，试样的显气孔率提高，体积密度、抗折强度和抗氧化性降低，抗渣性变化不大；1450℃3h处理后试样物相主要由3C—SiC、6H—SiC、刚玉、方镁石以及反应生成的尖晶石和莫来石组成，且随着电熔镁砂加入量的增加，尖晶石和莫来石的生成量也增加；在侵蚀面附近，刚玉颗粒边缘生成了厚度约80μm的尖晶石层。

Al2O3-SiC-C castables for iron trough with fused magnesite powder(0,3%,6%,9% and 12%) were prepared with brown fused corundum particle(5~3 mm,3~1 mm,≤1 mm),white fused corundum powders(≤0.088 mm),SiC particles(≤1 mm) and powders(≤0.088 mm),fused magnesite powders(≤0.088 mm),reactive α-Al2O3 micropowder,ultrafine SiO2,Si powder and sphere pitch as main starting materials,calcium aluminate cement as binder,vibrating moulding,curing,demoulding,drying at 110 ℃ for 24 h,firing at 1 100 ℃ for 3 h,1 450 ℃ for 3 h.Bulk density,apparent porosity,linear change rate,modulus of rupture,resistance to blast furnace slag,oxidation resistance,phase composition and microstructure were analyzed.The results show that:(1)With fused magnesite addition increasing,apparent porosity increases,bulk density,modulus of rupture and oxidation resistance lower,slag resistance varies slightly;(2)The main crystal phases in specimens fired at 1 450 ℃ for 3 h are 3C-SiC,6H-SiC,corundum,periclase,reaction-synthesized spinel and mullite,and forming quantity of spinel and mullite increases with fused magnesite addition increasing;(3)Near corroded side,spinel layer with about 80 μm thickness forms at corundum particles boundary.