关键词: 煤, 砷, 形态分析, 顺序提取, 原子荧光光谱法

Abstract: It is necessary to understand the existing forms of arsenic in power plant coals so as to provide some basic data to bridle arsenic pollution caused by power plants. Sequential chemical extraction procedure was adopted to extract the arsenic in various forms from five coal samples, which are namely to be obtained as non-specific adsorbed arsenic, specific adsorbed arsenic, amorphous and weak crystalline iron and aluminum hydrous oxides arsenic, crystalline iron and aluminum hydrous oxides arsenic and residue arsenic. The contents of arsenic in various extraction liquids were determined by atomic fluorescence spectrometer. The results show that the distributions of arsenic are different in the different coal samples. Arsenic mainly exists in amorphous and weak crystalline iron and aluminum hydrous oxides arsenic form and residue arsenic form. The total amount of arsenic in different coal samples is almost consistent with that measured in the coal samples digested by HNO₃, which demonstrates that there is no significant loss of arsenic in coals during the extraction process and the method and operation adopted are proven to be appropriate.

Key words: coal, arsenic, speciation analysis, sequential extraction, atomic fluorescence spectrometry