粉煤灰直接烧结制备多孔微晶玻璃

Preparation of Porous Glass Ceramics byDirect Sintering of Coal Fly Ash

以粉煤灰为原料,直接烧结粉煤灰至自膨胀温度点,制备多孔微晶玻璃.研究温度对多孔微晶玻璃结构和性能的影响.研究发现,在1200~1260℃,由石英和非晶玻璃体高温熔融形成的液相含量逐渐增加,析出的钙长石逐渐增多,由粘度的降低和晶体自膨胀引起的体积密度和孔隙率的变化率逐渐增大.1260~1320℃,粉煤灰中可熔融的石英和非晶态玻璃体已基本熔融,钙长石的量也基本稳定,体积密度的减小和孔隙率的增加主要是由升高温度引起的粘性流动速度的增大导致的.从1200~1320℃,多孔微晶玻璃的孔隙率逐渐增大,孔壁逐渐变薄,孔径分布逐渐变宽,多孔微晶玻璃的强度逐渐减小,变化率逐渐增大.本研究为粉煤灰资源化利用提供了新途径,同时也降低了多孔材料对天然原材料的需求.

Porous glass ceramics were prepared by directly sintering coal fly ash to self-expanding temperature point,using coal fly ash as raw material.The effect of temperature on the structure and properties of porous glass ceramics was studied.The result shows that from 1200℃to 1260℃,the content of liquid phase formed by high temperature melting of quartz and amorphous vitreous gradually increases,the precipitation of anorthite gradually increases,and the change rate of bulk density and porosity caused by the decrease of viscosity and crystal self-expansion gradually increases.From 1260℃to 1320℃,the fused quartz and amorphous vitreous in coal fly ash have been basically fused,and the amount of anorthite is basically stable.The decrease in bulk density and increase in porosity are mainly caused by the increase of viscous flow velocity caused by rising temperature.With the temperature ranging from 1200℃to 1320℃,the porosity of porous glass ceramics increases gradually,the pore wall becomes thinner,the pore size distribution becomes wider,and the strength of porous glass ceramics decreases and the change rate increases gradually.This study provides a new way for the utilization of fly ash and also reduces the demand for porous materials for natural raw materials.