SiO_2微粉加入量对Al_2O_3-SiC-C出铁沟浇注料性能的影响

Effect of microsilica addition on properties of Al_2O_3-SiC-C castables for iron trough

采用高铝矾土(8～5 mm)、棕刚玉(8～5、5～3、3～1 mm)、SiC(≤1、≤0.044 mm)、致密刚玉(≤1、≤0.044 mm)为主要原料,固定SiO2微粉和白泥的总加入量(w)为2.5%,研究了SiO2微粉加入量(其质量分数0、1%、1.5%、2%、2.5%)对Al2O3-SiC-C浇注料性能的影响。结果表明:试样在1 100、1 500℃分别保温3 h处理后,随着SiO2微粉加入量的增加即白泥加入量的降低,其加热永久线变化逐渐减少,显气孔率呈现先增大后降低的趋势,体积密度的变化趋势与显气孔率的正好相反,常温抗折强度及高温(1 450℃0.5 h)抗折强度呈现先增大后降低的趋势;当SiO2微粉加入量(w)为1.5%时,试样热震后的残余强度最大,SiO2微粉加入量(w)为2%的试样的强度保持率最低;在SiO2微粉加入量(w)为2%时,材料的抗渣侵蚀性能最好,继续增大SiO2微粉含量,抗渣侵蚀性能下降。综合各方面的因素,SiO2微粉和白泥复合使用时,SiO2微粉加入量(w)为2%左右,白泥加入量(w)为0.5%左右时,Al2O3-SiC-C快干浇注料具有最佳的综合性能。根据试验结果制备的快干浇注料在莱钢750 m3单铁口高炉铁沟使用,在未经任何修补的情况,主沟一次通铁量达到14万t。

Effects of microsilica additions（0,1%,1.5%,2% and 2.5% in mass） on properties of Al2O3-SiC-C castables for iron trough were researched using bauxite（8-5 mm）,brown corundum（8-5,5-3 and 3-1 mm）,SiC（≤1 and ≤0.044 mm） and dense corundum（≤1 and ≤0.044 mm） as main starting materials,and maintaining the total addition of microsilica and white clay at 2.5 mass%.The results indicate that：（1）after firing at 1 100 and 1 500 ℃ for 3 h,respectively,with microsilica addition increasing,that is,with white clay addition decreasing,the permanent change in dimensions on heating decreases gradually,the apparent porosity,cold modulus of rupture,and hot modulus of rupture（1 450 ℃ 0.5 h） firstly increase and then decrease,and the bulk density shows an opposite trend with apparent porosity;（2）after thermal shock,it performs the maximum residual strength with 1.5% of microsilica addition,and the lowest residual strength with 2% of microsilica addition;（3）the slag resistance is the best when the microsilica addition is 2%.Based on an overall consideration,the Al2O3-SiC-C rapid dry castables with 2% of microsilica and 0.5% of white clay have the optimum properties.The produced castables were used for the 750 m3 single taphole trough of Laiwu I ＆ S（Group） Co.,Ltd.and the main trough tapped 140 thousand tons hot metal without maintenance.