粉煤灰的类型、元素及矿物组成等理化性质是决定粉煤灰资源化利用途径的基础。为实现宁东能源化工基地周边燃煤电厂粉煤灰的潜在高值化利用,以马莲台电厂和银星电厂原煤、炉渣、粗灰、细灰为研究对象,用X射线荧光广谱(XRF)、电感耦合等离子体质谱(ICP-MS)手段分析粉煤灰化学组成及微量元素含量,用X射线衍射仪(XRD)、扫描电子显微镜分析粉煤灰矿物组成与形态特征。结果表明:马莲台电厂和银星电厂的粗灰、细灰氧化物化学组成以SiO2、Al2O3、Fe2O3和CaO为主,含少量TiO2、MnO、MgO、Na2O、K2O、P2O5;两电厂粉煤灰中CaO质量分数均小于10%、w(SiO2)+w(Al2O3)+w(Fe2O3)>75.39%,均属F型低钙粉煤灰;结晶矿物相均以石英、莫来石、赤铁矿、生石灰、钙长石、硬石膏、白云石、方解石等为主,玻璃质主要由SiO2和Al2O3组成,且以SiO2/Al2O3高质量比(2.18~2.36)为特征;粗灰和细灰中大多微量元素含量均低于欧洲飞灰中对应元素最大值,B、V、Co、Cu、Ga、Sn、Cs、Ti、Pb、Zn、Sn等挥发性强且冷凝性相对高的元素易在飞灰中富集,Mg、Ca、Sr、Fe、Mn、Cr、Ni等挥发性弱的元素易在炉渣中富集;两电厂粉煤灰中微量元素含量低、淋滤能力低、玻璃质含量高、SiO2/Al2O3质量比高,表明其在资源化利用过程中利用价值高、环境风险低。

The physicochemical properties of fly ash, such as type, element and mineral composition, are the foundation determiningthe multiple utilization of fly ash. To achieve the potential high-value utilization of fly ash from coal-fired power plants around the Ningdong Energy Base, the raw coal, slag, coarse ash, and fine ash from the Maliantai and Yinxing power plants were studied. The chemical composition and microelement concentration of the fly ash were analyzed by X-ray fluorescence broad spectrum (XRF) and inductively coupled plasma mass spectrometry (ICP-MS). The mineral composition and morphological characteristics of fly ash were analyzed byX-ray diffractometer (XRD) and scanning electron microscope. The results show that the chemical composition of the coarse and fine flyash from Maliantai and Yinxing power plants are mainly composed of SiO2, Al2O3, Fe2O3 and CaO, with a minor amount ofTiO2, MnO, MgO, Na2O, K2O and P2O5. The mass fractions of CaO in the fly ash of the two power plants are less than 10%, andw(SiO2)+w(Al2O3)+w(Fe2O3)>75.39%, classifying them as F-type low-Ca fly ash. The crystalline mineral phases mainly comprise ofquartz, mullite, hematite, lime, anorthite, anhydrite, dolomite, and calcite; glassy is mainly composed of SiO2 and Al2O3, and is characterized by a high SiO2 / Al2O3 mass ratio (2.18~2.36). The contents of most microelements in coarse ash and fine ash are lower thanthe maximum of corresponding elements in European fly ash. B, V, Co, Cu, Ga, Sn, Cs, Ti, Pb, Zn, Sn and other volatile and relatively high condensing elements are easy to be enriched in fly ash. Mg, Ca, Sr, Fe, Mn, Cr, Ni and other volatile elements are easy to beenriched in slag. The low microelement content, low leaching capacity, high glassy content and high SiO2 / Al2O3 mass ratio in the fly ashof the two power plants indicate its high utilization value and low environmental risk in the process of resource utilization.

0 引言

1 样品采集与分析方法

2 粉煤灰的化学特征及分类

3 粉煤灰的矿物组成特征

4 粉煤灰的元素地球化学特征

5 结论