燃煤含铁矿物的迁移转化特性研究

采用场发射扫描电镜结合X射线能谱分析仪(FSEM-EDX)系统研究了燃煤电站静电除尘器下各电场飞灰中磁珠的显微结构和化学组成,并利用热力学软件FACT计算预测了煤中含铁矿物的迁移转化过程．结果表明,外在含铁矿物在燃煤过程中易直接氧化形成结晶程度较好的铁氧化物相;内在含铁矿物与其他矿物在高温下熔合形成含Fe、Al、 Si的复杂的玻璃相,煤中含铁矿物的赋存特征、反应温度和气氛是影响含铁矿物迁移转化的主要因素。燃煤过程中Fe2 中间产物的形成以及Fe-O-S共熔体在炉内的长时间停留是结渣形成的重要原因。

TRANSFORMATION OF IRON-BEARING MINERALS DURING COAL COMBUSTION

Microstructures and chemical compositions of ferrospheres in fly ash from pulverized coal-fired power plants have been analyzed using field scanning electron microscopy with energy dispersive X-ray analysis (FSEM-EDX). Thermodynamic calculations (FACT) were used to predict the transformation of iron-bearing minerals under different conditions. The results show that excluded iron-bearing minerals oxidized to form ferro-oxides; included iron-bearing minerals mixed with other minerals to form complicated solid solutions. The transformation processes of iron-bearing minerals were related to temperature, atmosphere, and the occurrence of iron-bearing minerals. The formation of Fe2 intermediate products and Fe-S-O eutectic ash particles were the important sources of the initial layer which occur in deposits formed in coal burning systems.