摘要
利用X射线吸收精细结构分析 (XAFS)和铁的穆斯堡尔谱 (M ssbauer)对黔西南高砷煤中砷和铁的存在形式进行了研究。研究发现 ,高砷煤中的砷主要以高价砷的形式存在 ,也有少量以As2 O3 、砷黄铁矿、砷硫化物的形式存在。除 1个样品中的铁全部以顺磁性针铁矿或超顺磁性的针铁矿的形式存在外 ,其它样品中的Fe主要是黄铁矿中的Fe,约占全铁的 6 0 %～ 91% ;其次是黄铁钾矾中的Fe ,约占全铁的 9%～ 4 0 %。
Some small coal mines in Southwest Guizhou Province have high arsenic content, sometimes up to 3.5%. The application of high As bearing coals has caused about 3,000 people in arsenic poisoning in several villages. Coal samples from endemic arsenosis areas have been analyzed with instrument neutron activation analysis (INAA), X ray absorption fine structure (XAFS), and Mssbauer spectroscopy. The modes of occurrence of arsenic and iron in high As coals are discussed. Arsenic has different modes of occurrence in different samples. XAFS show that arsenic mainly exists in the form of As 5+ . The arsenic XANES spectra, with a main peak and a shoulder, indicate the presence of at least two different arsenic forms in each sample, with the possible exception of sample Jl As6 97A. The radial structure functions (RSFs) show one major peak at about 0.125 nm, corresponding to the As O distance in the AsO 4 3- anion unit, and a small peak at around 0.27 nm, corresponding to As 2O 3. For sample Jl As6 97A, the RSF peak at 0.125 nm is more intense, and arsenate is the dominant species of arsenic. Except for sample Jl As6 97A, the Mssbauer spectra show that 60%～91% of iron is in the form of pyrite. For sample Jl As6 97A all iron is present as paramagnetic or superparamagnetic goethite (α FeOOH ). The results demonstrate that arsenic exists mainly in the form of high valence, while the As 2O 3, arsenic pyrite and other sulfides comprise only a small fraction. Iron exists mainly in the form of pyrite (60%～91%) and jarosite (9%～40%) with one exception where all iron is present as paramagnetic or superparamegnetic goethite (α FeOOH). The difference between XAFS results and Mssbauer spectra indicates that arsenic and iron initially existed in different forms. It should be emphasized that in interpreting the results of XAFS spectroscopy other analytical rusults should also be considered.
出处
《高校地质学报》
CAS
CSCD
2003年第2期273-278,共6页
Geological Journal of China Universities
基金
国家自然科学基金项目 (40 1 330 1 0
4980 30 0 4 )
中国科学院王宽诚基金
北京正负电子对撞机同步辐射实验室基金
美国地质调查所(USGS)VentureCapitolFound联合资助
关键词
矿物谱学
煤
黔西南
高砷煤
赋存状态
spectroscopy
Southwest Guizhou
high As coal
arsenic
mode of occurrence
