贵州大方县百纳村高岭土的理化及工艺性能研究

从矿山采集代表性的高岭土样品,球磨并过80目筛备用。利用X射线荧光光谱仪(XRF)、X射线衍射仪(XRD)、综合热分析仪(DTA-TG)、场发射扫描电子显微镜(FE-SEM)和透射电子显微镜(TEM)对高岭土的化学成分、矿物组成、理化性质与微观形貌进行了表征,并详细考察了其多项工艺性能指标。结果表明:该高岭土的主要矿物组成为多水高岭石(84.77wt%)和绿脱石(1.33wt%),具有典型的六方管状结构,管直径在十几到几十个纳米不等,管长约为几百纳米。该高岭土可塑性较好,阳离子交换容量值很高,流动性和触变性小,干燥收缩大,干燥强度较低。由于该高岭土样品的Fe2O3(0.43wt%)含量低,从而具有较高的烧成白度,1250℃下烧成样品的白度为70.8%。

Physicochemical and Processing Properties of Bainacun Kaolin from Dafang in Guizhou

Kaolin samples were collected from Bainacun in Dafang,Guizhou,then ball-milled and screened through an 80-mesh sieve for analysis.The chemical composition,mineral composition,physicochemical properties and microstructure of the kaolin were characterized by XRF,XRD,DTA-TG,FE-SEM and TEM.Various processing properties of the clay were detailedly investigated.The results indicate that the main mineral composition of the kaolin includes halloysite(84.77wt%) and nontronite(1.33wt%).It is of typical hexagonal tubular structure.The tube diameter was about tens or dozens of nanometers,while the tube length was about hundreds of nanometers.The kaolin shows good plasticity,very high cation exchange capacity,less liquidity and thixotropy,large drying shrinkage and low drying strength.Meanwhile,its low Fe2O3(0.43wt%) content leads to high firing whiteness,which reaches 70.8% when fired at 1250℃.