焙烧温度对污泥陶粒烧胀过程及结构特征的影响

按质量比为m(污泥)∶m(盐渍土)∶m(蒙脱土)=75∶20∶5的配比,将料球分别烧至1000℃、1050℃、1100℃和1150℃,研究了焙烧温度对污泥陶粒烧胀过程和结构特征的影响。结果表明,1100℃时陶粒的主晶相是石英、蓝晶石和钙长石,1150℃时陶粒的主晶相是莫来石、石英和蓝晶石。莫来石是由蓝晶石转化而来,在高温时形成富硅铝和富钙的液相以及二液分相现象,最后生成莫来石、玻璃体和钙长石。陶粒烧胀的原因是在还原气氛下发生铁碳反应。陶粒内部形成玻璃体为主体,中间有莫来石增强相的结构,陶粒断面形成致密结构和均匀的封闭孔。

Effect of Sintering Temperature on Expansion Process and Structure Characteristics of Sludge Ceramsite

With the mass ratio of sludge:saline soil:montmorillonite being 75:20:5,the effect of calcina-tion temperature (1000 ℃,1100 ℃,1050 ℃ and 1150 ℃)on the sintering process and structural characteristics of sludge ceramsite was studied.Results showed that quartz,kyanite and anorthite were the main crystalline phases of ceramsite at 1100 ℃,while the mullite,quartz and kyanite were those of ceramsite at 1150 ℃.Rich silicon aluminum from kyanite and rich calcium from liquid phase were transformed at high temperature,which caused the dual-liquid-phase separation phenomenon.Meanwhile,kyanite was transformed into mullite,and in the end,mullite,vitreous and anorthite were produced.The reason of the burning expansion of the ceramic is the iron carbon reaction under the reduction atmosphere.A compacted structure of ceramsite with a few mullite reinforcing phases can be found in the glass phase,and the uniform and closed pores are formed in ceramsite section.