添加Li_2CO_3和BaCO_3对合成堇青石性能的影响  

Influences of Li_2CO_3 and BaCO_3 on property of synthesized cordierite

作　　者：刘靖轩[1] 薛群虎[1] 周永生[2] 屈启龙[1] 

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 [2]西南科技大学

出　　处：《耐火材料》2007年第6期421-423,共3页Refractories

摘　　要：采用煤系高岭土、滑石和镁砂为主要原料，在化学组成（w）为MgO13．23％，Al2O3 33．78％，SiO2 51．16％的研究配方（试样A）的基础上，分别添加1．0％、1．5％、2．0％的Li2CO3（对应试样编号为L1、L2、L3）或1．0％、2．0％、3．0％的BaCO3（对应试样编号为B1、B2、B3），以100MPa压制成636mm×50mm的圆柱状试样，在110℃干燥4h后，以3～5℃·min^-1的升温速度升至1340℃保温3h烧成，然后检测试样的烧后体积收缩率及体积密度、显气孔率和热膨胀系数，并采用XRD分析矿物成分，K值法测量烧后试样的堇青石相含量，以探讨添加Li2CO3和BaCO3对合成堇青石性能的影响。结果表明：随着Li2CO3添加量的增加，烧后试样的体积收缩率和体积密度逐渐增大，显气孔率逐渐减小，而添加BaCO3对堇青石合成过程中的烧结性影响不大；烧后试样A和B2中除分别含有为90％和95％的堇青石外未检测到其他晶相，但L1中还存在一定量的LiAlSi2O6相；添加剂Li2CO3或BaCO3均能降低合成堇青石的热膨胀系数。Coal series kaolinite,talc and magnesia were used as the starting materials. Based on the formula of the specimen A （ MgO 1 3.23 %, Al2O3 33.78 %, SiO2 51.16% ）, the specimens L1, L2,L3, B1, B2, B3 were prepared by adding 1.0% Li2CO3,1.5% Li2CO3,2.0% Li2CO3, 1.0% BaCO3,2.0% BaCO3,3.0% BaCO3 respectively,pressing into the cylinders with size of φ36 mm ×50 mm at 100 MPa,drying at 110 ℃ for 4 h,firing at 1 340 ℃ for 3 h with rising rate of 3 ～5 ℃ · min^-1. The volume shrinkage,bulk density,apparent porosity and the thermal expansion coefficient of fired specimens were measured,the phase composition was analyzed by XRD and the content of cordierite was calculated by K value method to research the influence of Li2CO3 and BaCO3 on property of synthesized cordierite. The results show that： （ 1 ） With increasing of Li2CO3 addition,the bulk density and volume shrinkage increase and apparent porosity decreases gradually. The addition of BaCO3 has a little effect on synthesis process of cordierite. （2）The fired specimens A and B2 contain 90% and 95% cordierite phase respectively, and have not other crystal phase, but specimen L1 has a certain amount of LiAlSi2O6 apart from the cordierite phase. （3）Li2CO3 and BaCO3 are both able to decrease the thermal expansion coefficient of synthesized cordierite.

关 键 词：合成堇青石 碳酸锂 碳酸钡 热膨胀系数 

分 类 号：TQ174.1[化学工程—陶瓷工业]