煤中砷的赋存状态  

THE MODES OF OCCURRENCE OF ARSENIC IN COAL

作　　者：赵峰华[1] 任德贻[1] 彭苏萍[1] 王运泉[2] 张军营[3] 丁振华[4] 丛志远[1] 

机构地区：[1]中国矿业大学资源与地球科学系,北京100083 [2]广州大学理学院,广东广州510405 [3]华中科技大学煤燃烧重点实验室,湖北武汉430074 [4]中国科学院地球化学研究所,贵州贵阳550002

出　　处：《地球科学进展》2003年第2期214-220,共7页Advances in Earth Science

基　　金：国家重点基础研究发展规划项目"煤中有害重金属赋存特征及其侵入环境的动态规律"(编号:G1999022212 01);国家自然科学基金项目"鄂尔多斯北部侏罗纪煤中有害微量元素的变异研究"(编号:49902013)共同资助.

摘　　要：砷是煤中常见的有害微量元素,由于其丰度较低,定量研究其赋存状态一直很困难。近年来,采用逐级化学提取实验方法对煤中不同赋存状态的砷进行了定量研究,综合分析这些研究可得出以下结论:①煤中砷的赋存状态包括硫化物态砷、有机态砷、砷酸盐态砷、硅酸盐态砷、水溶态和可交换态砷。总体上,硫化物态砷>有机态砷>砷酸盐态砷>硅酸盐态砷>水溶态和可交换态砷,但在不同的煤样品中,也表现出较大的差异性。②一般而言,煤中大部分砷存在于含砷黄铁矿中,含砷黄铁矿中的砷含量与黄铁矿的成因或类型有关。煤中的砷酸盐态砷主要与铁氧化物和氢氧化物共生;硅酸盐态砷主要进入粘土矿物晶格。③在砷含量较低的煤样品中,有机态砷含量较高,其中在褐煤和低煤级烟煤中,可提取出与腐殖酸和富里酸结合的砷。当前还难以确认有机态砷的化学结构。④贵州特高砷煤中砷的赋存状态较为复杂,在某些样品中与氧结合的有机态砷为主要的赋存状态。Arsenic is a common hazardous element in coal. It is always difficult to characterize its modes of occurrence quantitatively because of its low concentration in coal. In recent years, sequential chemical extract experiments were employed to determine modes of occurrence of arsenic quantitatively. The following conclusions can be drawn from these experimental data: ①The modes of occurrence of arsenic in coal include sulfide arsenic, organic arsenic, arsenate arsenic, silicate arsenic, soluble and exchangeable arsenic. Generally, the percentage sequence of arsenic in different states are as follows: sulfide arsenic>organic arsenic>arsenate arsenic>silicate arsenic>soluble and exchangeable arsenic. However, modes of occurrence of arsenic in different coal samples show big difference. ②Generally speaking, most of arsenic in coal are associated with arsenicbearing pyrite, and arsenic contents of pyrite are related to origin or genetic type of pyrite. Arsenic of arsenate in coal is mainly associated with Feoxides and Fehydroxide. Arsenic of silicate mainly comes into crystal lattice of clay minerals. ③Lowarsenic coals often have high organic arsenic. Humic acid and fulvic acid extracted from lignite and low rank bituminous coal also combine some of arsenic. However, chemical structure of organic arsenic in coal is still unclear currently. ④The modes of occurrence of arsenic in superhigh arsenic coal from Guizhou province are so complicated, and organic arsenic combined with oxygen are dominant occurrence of arsenic in some of these higharsenic coals.

关 键 词：煤 砷 赋存状态 逐级化学提取 

分 类 号：P595[天文地球—地球化学] P618.11[天文地球—地质学]