Ca_(2)Mg_(2)Al_(28)O_(46)对水泥窑过渡带用镁质耐火材料结构和性能的影响  

Effect of Ca_(2)Mg_(2)Al_(28)O_(46) Addition on Structure and Properties of Magnesia Refractories for Cement Kiln Transition Zone

作　　者：胡越 尹洪峰[1] 刘云 辛亚楼 刘宇驰 汤云 任小虎 袁蝴蝶[1] HU Yue;YIN Hongfeng;LIU Yun;XIN Yalou;LIU Yuchi;TANG Yun;REN Xiaohu;YUAN Hudie(College of Materials Science and Engineering,Xi′an University of Architecture&Technology,Xi′an 710055,China)

机构地区：[1]西安建筑科技大学材料科学与工程学院,西安710055

出　　处：《硅酸盐学报》2024年第6期2118-2130,共13页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(51572213);先进耐火材料国家重点实验室开放课题基金项目(SKLAR202301)。

摘　　要：水泥回转窑过渡带由于难于结窑皮和所用耐火材料热导率较高,窑壳外表面温度高,散热损失大。本工作以氢氧化镁、碳酸钙和煅烧α-氧化铝为原料合成出Ca_(2)Mg_(2)Al_(28)O_(46),以此为骨料和烧结镁砂制备出方镁石–尖晶石–铝酸钙耐火材料。借助扫描电子显微镜、X-射线衍射仪等手段研究Ca_(2)Mg_(2)Al_(28)O_(46)的添加和烧成温度对镁质耐火材料结构和性能的影响。结果表明:1) Ca_(2)Mg_(2)Al_(28)O_(46)引入到镁质耐火材料中,因烧成过程方镁石存在使Ca_(2)Mg_(2)Al_(28)O_(46)发生分解,方镁石–尖晶石–铝酸盐三元体系在高温下形成液相,借助于液相辅助Kirkendall效应形成了孔洞实现了轻量化,并且随着Ca_(2)Mg_(2)Al_(28)O_(46)加入量增加,材料显气孔率升高,体积密度、耐压强度和荷重软化温度降低;相同Ca_(2)Mg_(2)Al_(28)O_(46)加入量,降低Ca_(2)Mg_(2)Al_(28)O_(46)粒度可使上述提及性能提高。2)随着烧成温度升高,材料的显气孔率降低、体积密度增加,但耐压强度并未升高,荷重软化温度保持在1 540℃以上较高的水平,当加入10%(质量分数)、0.50~1.00 mmCa_(2)Mg_(2)Al_(28)O_(46)颗粒,材料在1 700℃烧成时荷重软化温度可达1 603℃。3) 1 350℃侵蚀实验结果表明,引入10%粒度为0.088~0.500 mm Ca_(2)Mg_(2)Al_(28)O_(46)颗粒的样品,在1 650℃烧成具有最好的抗水泥物料侵蚀性能。Introduction Cement industry is one of the major carbon-emitting industries,which is characterized by a thermal efficiency below 54%and an energy consumption ranging from 3–4 GJ per ton of cement clinker.China annual average cement production reaches 2341 million tons,contributing to approximately 14.3%of the total CO_(2) emissions.In addition to the CO_(2) emissions resulting from the high-temperature decomposition of limestone,which serves as a primary raw material,the cement production process significantly contributes to elevated CO_(2) emissions due to its substantial energy consumption.The cement rotary kiln is a pivotal equipment in the production process,with its high energy consumption primarily attributed to subpar performance of certain refractory materials and an irrational configuration.Consequently,this leads to elevated temperatures(reaching up to 350–400℃)in both the transition zone and firing zone of the kiln shell,resulting in a substantial energy loss accounting for 8%–15%of the total heat input.Previous studies demonstrated that the implementation of light weight refractory materials could effectively mitigate heat loss from the kiln shell,thereby enhancing energy efficiency.The CA6/MA composite material C_(2)M_(2)A_(14) has the excellent high-temperature performance and chemical stability of both CA6 and MA.It is proven to be an effective ladle lining material in the non-slag line part.Incorporating a proper quantity of Fe_(2)O_(3) during the synthesis process of C_(2)M_(2)A_(14) results in a denser product under identical firing conditions.In this paper,C_(2)M_(2)A_(14) was introduced into magnesite refractories to achieve light weighting of magnesite refractories.In addition,the mechanism of achieving light weighting and the effects of addition amount and particle size on the microstructure and properties of magnesite refractories were also investigated.Methods Magnesium hydroxide,calcium carbonate and calcinedα-alumina fine powders as raw materials were mixed.Also,1%Fe_(2)O_(3) wa

关 键 词：钙镁铝氧化物 Kirkendall效应 镁质耐火材料 抗水泥侵蚀 水泥窑过渡带 

分 类 号：TQ175.7[化学工程—硅酸盐工业]