以氩氧脱碳(AOD)炉用后镁钙砖为原料,配以电熔镁砂在1873K保温2h,分别合成出MgO含量(质量分数)分别为80%、70%、60%的再生镁钙砖样品。研究了样品物相、显微结构、常温力学性能、高温抗折强度与抗水化性能。结果表明:样品组成主要为MgO、CaO、少量Ca3SiO5和4CaOAl2O3Fe2O3。MgO以较大颗粒连续弥散分布,CaO被MgO包裹呈孤岛状均匀分布。随用后镁钙砖加入量的增加,常温力学性能增强,高温(1373K)抗折强度仅在MgO含量为60%的样品中出现明显下降。样品具有良好的安定性和抗水化性能,最大水化质量增加率仅为0.82%,随用后镁钙砖加入量的增加,抗水化性能变差。
Regenerated MgO-CaO brick samples with MgO contents of 80%, 70%and 60%, respectively, were prepared with spent MgO-CaO bricks for AOD furnace and fused magnesite as raw materials at 1 873 K for 2 h. The phase composition, microstructure, mechanical property and the hydration resistance of the recycled samples at various composition were investigated. The results show that the recycled samples contain MgO and CaO, which are homogenously dispersive in the samples with a small amount of Ca3SiO5 and 4CaO?Al2O3?Fe2O3. The mechanical property at room temperature increases with increasing the spent MgO-CaO bricks content in the samples. A significant decrease of the flexural strength at 1 373 K occurs for the sample with MgO of 60%. The maximum weight gain rate is 0.82%, showing the recycled sample has a superior hydration resistance. The hydration resistance decreases as the spent MgO-CaO bricks content increases in the recycled samples.