分散剂对二氧化硅微粉浆料流变性的影响  

Effects of Dispersants on Rheological Properties of Silica Fume Slurries

作　　者：王超[1] 石颖恒 俞馗玲 李华春 员文杰[1,3] WANG Chao;SHI Yingheng;YU Kuiling;LI Huachun;YUAN Wenjie(The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;Saint-Gobain Research(Shanghai)Co.Ltd.,Shanghai 200245,China;National-provincial Joint Engineering Research Center of High Temperature Materials and Lining Technology,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China)

机构地区：[1]武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉430081 [2]圣戈班研发(上海)有限公司,上海200245 [3]武汉科技大学高温材料与炉衬技术国家地方联合工程研究中心,湖北武汉430081

出　　处：《陶瓷学报》2020年第5期678-685,共8页Journal of Ceramics

基　　金：湖北省中央引导地方科技发展专项(2019ZYYD076)。

摘　　要：由于烟气氧化冷凝制得的二氧化硅微粉呈球形结构、粒径小而常被用于浇注料中以增加流动性。二氧化硅微粉的类型、成分和粒度等特性以及不同分散剂的选用会对其浆料的流变性能产生较大影响。本工作采用同轴圆筒式流变仪测试了体积分数为30%二氧化硅微粉浆料的流变性能,并利用Herschel-Bulkey模型对浆料的流变曲线进行拟合,分析了二氧化硅微粉自身特性对流变性的影响,以及不同分散剂对二氧化硅微粉浆料屈服应力、表观粘度以及流变指数等的影响。结果表明,含锆二氧化硅微粉的pH值偏酸性,普通二氧化硅微粉的pH值偏弱碱性,实验所用三种分散剂均能降低浆料的粘度值。其中,含锆二氧化硅微粉因为ZrO2的表面积较大,易与SiO2表面之间发生摩擦从而发生团聚,导致其粒径更大,因此,在加水量一定时浆料中流动的自由水含量更多,粘度更低。对于呈酸性的含锆二氧化硅微粉而言,加入氧化铝为载体的聚羧酸盐型分散剂后其浆料稠度系数K与屈服应力值τy显著减小;偏弱碱性的普通二氧化硅微粉在加入聚乙二醇基分散剂后其浆料稠度系数K与屈服应力值τy最小,这类分散剂更适合用于普通二氧化硅微粉体系;以铝酸钙水泥为载体的聚丙烯酸盐型分散剂仅对部分含锆二氧化硅微粉分散效果较好。Silica fume has been widely used in castables for increasing flowability,due to its spherical morphology and small particle size.Characteristics,such as type,composition and particle size of silica fume and dispersants have significant influences on the rheological properties of the slurries.The rheological properties of silica fume slurries with a volume fraction of 30%were characterized by using a coaxial cylinder rheometer,while the rheological curves of the silica fume slurries were fitted with the Herschel-Bulkey model.Effects of dispersants on yield stress,viscosity and rheological index of the silica fume slurries were analyzed.It is found that the zirconia-containing silica fume is acidic and the common silica fume is weak alkaline.The zirconia-containing silica fume that is easily rubbed with the SiO2 leads to agglomerate,resulting in larger particle size and more free water flowing in the slurries to reduce the viscosity at a fixed content of water,because of the larger specific surface area of ZrO2.For acidic zirconia-containing silica fume,both the consistency coefficient(K)and the yield stress(τy)decreased significantly with the addition of alkaline polycarboxylate supported on alumina.For common silica fume,the consistency coefficient(K)and the yield stress value(τy)decreased significantly when adding polyethylene glycol.The polyacrylate type dispersants supported on calcium aluminate cement only have promising dispersion effect on some zirconia-containing silica fumes.

关 键 词：分散剂 二氧化硅微粉 pH 流变性能 Herschel-Bulkey模型 

分 类 号：TQ174.75[化学工程—陶瓷工业]