煤粉与钙基复合添加剂混烧的灰分矿相特性

MINERAL CHARACTERISTICS IN ASH WHEN CO-FIRING COAL AND CALCIUM-BASED COMPOUND ADDITIVES

在自行设计的小型高温试验炉上对煤中掺入钙基复合添加剂进行了静态烧成试验 ,并对所烧成的灰样进行了XRD分析 ,着重讨论了温度和时间以及添加剂对所烧成灰分的矿相特性的影响 .试验结果表明 ,当温度在 10 0 0℃时 ,灰分中的矿物主要以游离态的氧化物形式存在 ,部分矿物生成钙铝黄长石 (C2 AS)、硅酸二钙 (C2 S)等 ;当温度高于 12 0 0℃时 ,灰分中的主要矿物是C2 AS、C2 S .同时在高温下有硫铝酸钙 (C4 A3S)生成 。

Mineral characteristics of ash when combusting pulverized coal and calcium-based compound additives were studied with a lab-scale furnace used for combustion test. The mineralogical composition of the collected ash was determined by X-ray diffraction (XRD). The effects of temperature, residence time and content of additives on the mineral characteristics of ash were analyzed. The results revealed that the minerals in ash were principally free oxides and a small amount of gehlenite and dicalcium silicate at 1000°C; as the firing temperature increased above 1200°C, the major minerals in the ash were gehlenite and dicalcium silicate. Moreover, It was found that anhydrous calcium aluminosulfate formed at a high temperature, which plays the role of desulfurization.