Abstract: To enhance the resource utilization of magnesite tailings and reduce the production cost of magnesia-based refractories,porous MgO-Mg₂SiO₄-MgAl₂O₄ aggregates were synthesized in-situ using magnesite tailings and coal gangue powder as raw materials,firing at 1 300 ℃ for 4 h.The effects of the coal gangue powder additions (0,10%,20%,30%,and 40%,by mass) on the phase composition,microstructure,bulk density,apparent porosity,cold crushing strength,and thermal shock resistance of the specimens were investigated.The results show that:(1)with the increase of the coal gangue powder addition,the linear shrinkage decreases the specimens first decrease and then increase decreases,the apparent porosity decreases,the bulk density and the cold crushing strength increase,and the thermal shock resistance first increases and then declines;(2)when the coal gangue powder addition is 30%,the specimen primarily consists of the crystalline phases of MgO,Mg₂SiO₄,and MgAl₂O₄,showing the optimal comprehensive performance:the linear shrinkage of 12.7%,the volume shrinkage of 30.5%,the apparent porosity of 43.4%,the bulk density of 1.81 g·cm^-3,the cold crushing strength of 56.0 MPa,and the crushing strength retention ratio of 83.3% after 3 thermal shocks.

Key words: magnesite tailings, coal gangue, porous aggregates, magnesium aluminate spinel, forsterite

摘要： 为了提高菱镁矿尾矿资源化利用,降低镁质耐火材料生产成本,以菱镁矿尾矿与煤矸石粉为原料,经 1 300 ℃保温4 h原位合成了MgO-Mg₂SiO₄-MgAl₂O₄多孔骨料。研究了煤矸石粉加入量(加入质量分数分别为0、10%、20%、30%和40%)对试样物相组成与显微结构、体积密度和显气孔率、常温耐压强度和抗热震性能的影响。结果表明:1)随着煤矸石粉加入量的增加,试样线收缩率先降低后升高,体积收缩率降低,显气孔率降低,体积密度升高,常温耐压强度升高,抗热震性先上升后降低;2)当煤矸石粉加入量为30%(w)时,试样的主晶相为MgO、Mg₂SiO₄和MgAl₂O₄,综合性能最优,其线收缩率为12.7%,体积收缩率为30.5%,显气孔率达 43.4%,体积密度为1.81 g·cm^-3,常温耐压强度为56.0 MPa,3次热震后的耐压强度保持率为83.3%。

关键词: 菱镁矿尾矿, 煤矸石, 多孔骨料, 镁铝尖晶石, 镁橄榄石