煤燃烧过程中痕量元素的分类研究

采用原子吸收分光光度计(带测汞装置)、石墨炉原子吸收光谱仪和X射线荧光光谱仪，测定了一台220t／h煤粉炉中原煤、底渣和飞灰中9种痕量元素的质量分数．除As因质量分数低不能归类外，其他痕量元素按照在飞灰中相对富集系数不同，可分成3类：第1类是Pb，Zn；第2类是Mn，Cr，Se，Hg；第3类是Ba，Cd．按照飞灰相对于底渣痕量元素富集程度不同，可分成两类：第1类是Mn，Cr；第2类是Pb，Bd，Se，Zn，Cd，Hg．按照痕量元素挥发性和在燃烧产物中的分布规律，可分成3类：第1类是Hg；第2类是Pb，Ba，Zn，Cd；第3类是Mn．Se介于第1类元素和第2类元素之间．Cr同时表现出第1类和第3类元素性质．研究还发现除Mn外，其他元素在飞灰中的富集程度随粒径减小而增加；Pb比Cd更容易挥发．

Study on groups of trace elements during coal combustion

Groups of trace elements during coal combustion are summarized at the beginning of this paper. By using two kinds of atomic absorption spectroscopy and X ray fluorescence, the contents of nine trace elements in raw coal, bottom ash and fly ashes were measured in a 220?t/h pulverized coal boiler. As content in coal and particle ash is too low to be classified. Other elements may be classified into three groups according to the contents in fly ash: group 1: Pb, Zn; group 2: Mn, Cr, Se, Hg; group 3: Ba, Cd. According to the different relative enrichment degree of trace elements in fly ash compared with that in bottom ash, these elements may be classified into two groups: group 1:Mn, Cr and group 2: Pb, Ba, Se, Zn, Cd, Hg. In addition, these trace elements may also be classified into three groups according to their occurrence and volatility during combustion: group 1: Hg; group 2: Pb, Ba, Zn, Cd; group 3:Mn. Se may be located between group 1 and group 2. Cr has properties of both group 1 and group 3. It is also found that the relative enrichments of trace elements (except Mn) increase with decreasing fly ash particle size. Pb has a stronger volatilization than Cd.