用硅溶胶对硅莫砖再生骨料进行浸渍处理, 研究了硅溶胶含量(质量分数)对骨料性能的影响。用扫描电子显微镜和能谱仪对浸渍后硅莫砖骨料的显微结构进行表征。通过水润湿角测试判断硅莫砖骨料的水润湿性。结果表明: 骨料经浸渍处理后, 吸水率从6.9%降低到2.6%。骨料的水润湿性有了较大的改善, 水润湿角从55°降低到7°。将浸渍后的硅莫砖替代棕刚玉, 作为再生骨料应用于Al2O3-SiC-C浇注料中, 当硅溶胶含量为15%浸渍的硅莫砖骨料替代棕刚玉时, 1 450 ℃热处理后浇注料的显气孔率最低(17.1%), 常温耐压强度最高(73.7 MPa), 比以棕刚玉为骨料的浇注料的强度提高了45.7%, 浇注料热震后残余抗折强度和残余抗折强度保持率分别提高了69.4%和24.1%, 综合性能最佳。

For the improvement of the fluidity of castables with recycled aggregates of mullite-SiC bricks due to their high porosity, high water absorption and massive cracks, silica sol was used to impregnate mullite-SiC brick aggregates. The effect of silica sol concentration on the aggregate properties of mullite-SiC bricks was investigated. The microstructures and the element distributions of modified mullite-SiC bricks aggregate were analyzed by scanning electron microscopy coupled with energy dispersive spectroscopy. The water wettability of mullite-SiC brick aggregates was characterized via water contact angle measurement. The results show that after the impregnation of mullite-SiC brick aggregates, the water absorption of mullite-SiC brick aggregate reduces from 6.9% to 2.6%, and the water contact angle decreases from 55 ° to 7 °, thus improving the water wettability of the aggregate. The impregnated mullite-SiC bricks were used as recycled aggregates instead of brown corundum in Al2O3-SiC-C castables. In addition, the effect of aggregates on the properties of castables was also investigated. The results indicate that Al2O3-SiC-C refractory castables with silica sol concentration of 15% modified mullite-SiC bricks aggregates after heat-treated at 1 450 ℃ have the minimum apparent porosity of 17.1% and the maximum cold compressive strength of 73.7 MPa, which is 45.7% greater than the strength of castables with brown corundum as aggregates. Meanwhile, the residual strength and the residual strength ratio of castables after thermal shock are increased by 69.4% and 24.1%, respectively.