贵州毕节金银山粘土的理化及工艺性能研究

从矿山采集具有代表性的粘土,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)对粘土的化学成分、矿物组成、理化性质和微观形貌进行了表征,并详细考察了其多项工艺性能指标.研究结果表明:该粘土的主要矿物组成为白云母(27.69wt％)、高岭石(33.12wt％)、石英(35.31wt％)和板钛矿(0.91wt％),呈典型的片状结构.该矿物原料可塑性非常好、阳离子交换容量低、流动性较大、触变性较小、干燥收缩很小、干燥强度较大.由于该粘土矿物中碱金属和碱土金属总含量不高(4.73wt％),因此烧结温度较高(烧结温度范围为1250℃～1300℃),并且其含有较多的Fe2O3(1.22wt％)和TiO2 (0.90wt％),导致烧成(1250℃)白度较低,仅为41.12％.

Physicochemical and Processing Properties of Jinyinshan Clay from Bijie in Guizhou

Clay specimens were collected from Jinyinshan in Bijie,Guizhou,then ball-milled and screened through an 80-mesh sieve for analysis.The chemical composition,mineral composition,physicochemical properties and microstructure of the clay were characterized by XRF,XRD,DTA-TG,FE-SEM and TEM.Its various processing properties were also investigated.The results indicate that the main mineral composition of the clay includes muscovite(27.69wt%),kaolinite(33.12wt%),quartz(35.31wt%) and brookite(0.91wt%).It is of typical laminar structure.The clay shows very good plasticity,low cation exchange capacity,high liquidity,less thixotropy,small drying shrinkage and high drying strength.Due to its low contents of alkaline metal oxides and alkaline earth metal oxides(4.73wt%),the clay is sintered at a relatively high temperature(1250℃~1300℃).And also,its relatively high Fe2O3(1.66wt%) and TiO2(0.23wt%) contents lead to low firing whiteness,which is only 41.12% when sintered at 1250℃.