固硫灰渣中含硫矿物的种类及分布规律

Study on the varieties and distribution of sulfur minerals in CFBC ash/slag

与普通粉煤灰相比,固硫灰渣中硫含量较高(以SO3计可达10%),易造成体积安定性不良而限制了其建材资源化利用。采用X射线衍射和化学分析方法研究了固硫灰渣中含硫矿物的种类,利用筛分法、密度分离法和微观分析法(SEM和EDS)研究固硫灰渣中含硫矿物的分布规律。结果显示:固硫灰渣中含硫矿物基本以Ⅱ-硬石膏形式存在;硬石膏在固硫灰渣中分布不均匀,主要富集在颗粒较细、密度较大的致密颗粒上。

Compared to normal pulverized coal combustion （PC） fly ash, the SO3 content of circulating fluidized bed combustion （CFBC） ash/slag is higher （exceeding 10% or more by weight） ,which tends to make a negative impact on the volume stability of the gel system, limiting the utilization of CFBC ash/slag as construction materials. In this study, the varieties of sulfur minerals in CFBC ash/slag were investigated by X-ray diffraction and chemical analysis. In addition, the distribution of sulfur minerals was also studied using sieving test, density separation test, SEM and EDS. The results show that the sulfur content in CFBC ash/slag exists mainly as Ⅱ -anhydrite. The distribution of sulphur in CFBC ash/slag is non-uniform and most sulphur is presented in the denser particles with smaller diameter or higher density.