重烧气氛对水泥窑用镁铁铝尖晶石砖性能的影响

摘要

为了研究共处置水泥窑常用的高铁镁砂-镁铝尖晶石砖和方镁石-铁铝尖晶石砖在使用过程中气氛波动下的稳定性,分别在氧化气氛(空气)及埋炭还原气氛下,将高铁镁砂-镁铝尖晶石砖、方镁石-铁铝尖晶石砖分别置于电炉1 450℃保温4h条件下进5次重烧试验,然后对不同重烧次数下高铁镁砂-镁铝尖晶石砖、方镁石-铁铝尖晶石砖的显气孔率、体积密度、物相组成和显微结构进行对比分析,进而评判两种砖抗气氛波动的稳定性.结果发现:高铁镁砂-镁铝尖晶石砖经氧化和还原气氛重烧后的显气孔率、体积密度、物相组成和显微结构无明显变化;而方镁石-铁铝尖晶石砖重烧过程中则有大量新相生成,导致显微结构破坏严重,显气孔率和体积密度随着重烧次数增加有较大变化,特别是还原气氛下尤为严重.可见,高铁镁砂-镁铝尖晶石砖抗气氛波动性能要优于方镁石-铁铝尖晶石砖的.%High iron magnesia-spinel bricks and periclase-hercynite bricks were reheated 5 cycles under air oxidizing atmosphere or carbon-embedded reducing atmosphere at 1 450 ℃ for 4 h in electrical furnaces in order to research their stability under atmosphere fluctuation in cement kilns.Then the apparent porosity,bulk density,phase composition and microstructure after different reheating cycles were analyzed to evaluate their anti-atmosphere fluctuation stability.The result shows that the apparent porosity,bulk density,phase composition and microstructure of the high iron magnesia-spinel bricks reheated under oxidizing or reducing atmosphere have no significant change;while in the reheated periclase-hercynite bricks,there forms a lot of new phases,the microstructure is damaged severely,and apparent porosity and bulk density have a greater change with the increase of the reheating cycles,and the damage of periclase-hercynite bricks reheated under reducing atmosphere is particularly serious.The anti-atmosphere fluctuation stability of high iron magnesia-spinel bricks is much better than that of periclase-hercynite bricks.