燃煤过程中元素的分异特征与淋滤实验研究  

Partitioning of Elements During Coal Combustion and Leaching Experiments

作　　者：王文峰[1] 秦勇[1] 宋党育[2] 王钧漪[1] 

机构地区：[1]中国矿业大学资源与地球科学学院,江苏徐州221116 [2]河南理工大学资源与环境学院,河南焦作454108

出　　处：《中国矿业大学学报》2009年第4期481-487,共7页Journal of China University of Mining & Technology

基　　金：国家自然科学基金项目(40772102;40730422;40502014);新世纪优秀人才支持计划(NCET-08-0839)

摘　　要：运用AFS，INAA，ICP-MS，ICP—AES，XRD等方法分析了宁夏石嘴山电厂原煤、飞灰、底灰中硫等43种元素的含量与矿物组成，基于燃烧与淋滤实验，探讨了这些元素的燃烧分异特征及As等11种有害微量元素的淋滤行为．结果表明：元素在燃煤固体产物中的分布主要受其挥发性与赋存方式控制．燃煤过程中元素的挥发程度与其单质及其化合物的沸点或熔点的高低有关，易挥发的、以有机相赋存的以及赋存在亚微米／纳米级矿物中的元素（如Al和Na）向细粒飞灰中富集，而大多数元素基本不挥发，在飞灰与底灰中均匀分布．在877～1300℃的燃烧温度，元素As，Cr，K，Mg，Mn，Mo，Pb，Sb，Zn的挥发率受影响显著；煤及其燃烧产物中微量元素的淋滤行为主要与其自身的地球化学性质以及赋存状态有关．飞灰、底灰受酸性介质淋滤时，低挥发性的元素有低的淋出，而挥发性较高的元素易于淋出；As，Br，Cd，Cu，Hg，Pb，S，Sb与Se在燃煤过程中有较高的挥发率，Co，Cd，Ni，Mo及U在酸性介质中的淋出质量浓度超过有关水环境质量标准，存在环境危害潜势．The mineral component and content of sulfur and 42 major and trace elements of the feed coal, fly and bottom ashes collected from Shizuishan coal-fired power plant, Ningxia, China were analyzed using AFS, INAA, ICP-MS, ICP-AES, XRD. Based on the coal combustion and leaching experiments, the partitioning of these elements during coal combustion and the leaching behavior of the 11 potentially hazardous elements, including As, Cd, Co, Cr, Hg, Mo, Ni, Pb, Se, Th and U were investigated. The results show that the distribution of elements in the fly and bottom ashes is controlled by their volatilities and modes of occurrence in the coal. The degree of volatilization of elements may be mainly associated with boiling/melting points of these elements and their compounds. The elements easily volatilized, organically bound or associated with sub-micrometer and nano minerals （e. g. Al and Na） tend to be enriched in the fine fractions of fly ash, and most elements do not vaporize which are approximately equally partitioned in the fly and bottom ashes. The emission rates of As, Cr, K, Mg,Mn, Mo, Pb, Sb, and Zn are notably influenced by the temperature ranging from 877 ℃ to 1 300 ℃. The leaching behavior of elements depend significantly on their geochemical properties and modes of occurrence. The elements with a low degree of volatilization are not easily leached, while volatile elements easily leached under the acid conditions. Arsenic, Br, Cd, Cu, Hg, Pb, S, Sb and Se show a higher emission rate during coal combustion, and the leached concentrations of Cd, Co, Mo, Ni and U in the acid media exceed their limited concentrations recommended in relevant environment quality standards for water, which will harm the environment.

关 键 词：原煤 飞灰 底灰 元素 燃烧 淋滤 分异 

分 类 号：X523[环境科学与工程—环境工程]