陕西煤中硒的环境地球化学特征

Characteristics of environmental geochemistry of Se in Coals of Shaanxi province

研究了陕西的各成煤期煤中Se的含量、分布规律、赋存状态、采煤燃煤环境影响及燃煤Se脱除等环境地球化学问题.对Se含量及分布规律研究的结果表明,不同地区、不同成煤期煤中Se的含量有较大的差异,表现在随着成煤时代由老到新,煤化程度由高到低,煤中Se的含量减少;从南到北,煤中Se含量从高到低.赋存状态分析表明,煤中Se的含量与成煤环境、煤中S含量有着一定的对应关系,煤中S越高,尤其是黄铁矿硫的含量越高,煤中Se的含量也越大,说明在中、高S煤中,Se主要赋存于黄铁矿中,而在特低、低S煤中Se的赋存状态与有机质有关.燃烧实验表明,煤中Se会随着煤炭的开采和利用进入表生环境,从而对表生生态环境构成一定的影响,钙基固硫剂可抑制燃煤Se的排放.

Selenium content of coals, its distribution laws, existence states, environmental effect, retention techniques and other geochemistry characteristics in Shaanxi are studied in detail. The results selenium contents and distribution laws study show that Selenium contents of coal during different coalforming periods are different, which shows selenium content of coal decreases along with the coalforming ages from old to new, and coal rank from high to low. Selenium content decreases from south to north in Shaanxi province. Analysis about selenium existence states that indicates selenium in Shaanxi coals are related with coalforming environment and sulfur content of coal, which shows that more sulfur content of coal, particularly, more pyrite in coal, higher the selenium content in coal. This illustrates that in the moderatehigh sulfur coal, selenium of coal mainly exists in pyrite, but in the very lowlow sulfur coal, it relates with organic sulfur. Selenium of coal will enter the surface environment when coal resource being mined and utilized and will affect ecological environment and peoples health. Calciumbased desulfurizer can control selenium volatility in coal combustion.