神华煤中含铁矿物质及其在煤粉燃烧过程中的转化

Iron-Bearing Minerals of Shenhua Coals and Their Conversion During Pulverized Coal Combustion

采用57Fe Mssbauer谱仪对多种典型神华煤样及其在沉降炉中燃烧生成的煤灰样中的含铁成分进行定量测定和分析,研究了神华煤中含铁矿物的存在形式、含量及其在煤粉燃烧条件下的转化.研究表明,神华煤样中含铁矿物质包括黄铁矿、菱铁矿和含Fe2+的伊利石;黄铁矿和菱铁矿在燃烧过程中主要转化成氧化物,但也有相当一部分与硅酸盐反应生成了含铁玻璃体,从而有利于结渣的形成和发展;燃烧过程中黄铁矿及菱铁矿发生了破碎,导致破碎峰附近尺寸的颗粒中出现了Fe2O3的富集.

The various samples of Shenhua coals and their ashes burned Out in drop furnace have been quantitatively measured and analyzed by means of ^57Fe Moessbauer spectroscopy technology. The form and content of Iron-bearing material appealed as well as which conversion in pulverized coal particular during combustion are investigated. It was found that the iron-bearing minerals in Shenhua coals included pyrite, siderite and Fe^2＋-containing illite. Pyrite and siderite in the parent coals have mainly conversed into oxides, while a considerable amount of them have reacted with silicates to form iron-containing glass silicates, which consequently may cause slagging formation and build-up. In addition, X-ray fluorescence spectroscopy was used to characterize the size distribution of Fe2O3 in the fine ash particles collected in the combustion experiments. The results indicated the significant fragmentation of pyrite and siderite during combustion, which resulted in the enrichment of Fe2O3 in the particular with the size near the fragmentation mode.