某高铝矾土低温煅烧结晶特性研究

Crystallization Properties Research of High Alumina Bauxite at Low Calcination Temperature

为了解某高铝矾土低温煅烧水化活性被激发的机理,试验借助XRD分析和SEM分析的手段,从产物种类、结晶状态和表面形貌等方面的变化研究了试样在不同煅烧温度下的结晶特性,以及煅烧温度对生成物刚玉晶体活性的影响。结果表明,试样在500℃左右煅烧时的脱水速率最快,煅烧熟料的结晶度最差,晶相的胶凝反应活性最大,最适合作为胶凝材料掺合料制造矾土水泥和灌浆材料等;高铝矾土在煅烧升温过程中,一水硬铝石的层状结构逐渐粘合,形成刚玉的粒状结构,同时颗粒表面的横纹逐渐清晰,说明晶体结晶程度逐步增加,反应活性逐步降低。

In order to find the activation mechanism of high alumina bauxite calcination at low temperature,the crystallization characteristics of bauxite calcined at different temperatures were studied and the effects of calcination temperature on the activity of the corundum crystals were investigated by combining the product type,crystal state and surface morphology. Xray diffraction(XRD)was used to detect the type and crystal state of the calcined high alumina bauxite. The morphology of the calcined product was observed by scanning electron microscopy(SEM). The results show that the high alumina bauxite calcined at 500 ℃ has the fasted dehydration speed,lowest crystallinity and the highest gelation activity,and is more suitable as a cementitious material admixture in the manufacture of alumina cement and grouting materials. During the calcination and heating process,the layered structure of diaspore is gradually bonded to form the granular structure of corundum,and the horizontal stripes on the surface of the particles are gradually clear,indicating that the crystallinity of the crystal is gradually increased and the reactivity is gradually reduced.