石煤砷的赋存形态对砷迁移释放的影响

Influence of Chemical Speciation of Arsenic in Stone-like Coal on Arsenic Release and Migration

高砷石煤燃烧是陕西南部秦巴山区砷中毒流行的主要因素,煤燃烧的砷释放过程不仅与砷元素化学性质、砷含量有关,也与砷赋存形态有关。文章利用连续化学浸提法对陕南石煤砷的赋存形态进行了分析,并探讨了各赋存形态对石煤砷迁移和燃烧释放率的影响。结果表明,高砷石煤砷主要以硫化物结合态存在,其含量占煤砷含量的75%以上;石煤燃烧的砷释放率与煤中残渣态砷有显著的负相关,相关系数为-0.773,P<0.01;煤砷溶出率与可交换态砷和硫化物结合态砷均呈显著正相关,相关系数分别为0.983(P<0.05)和0.796(P<0.05)。

High level of toxic trace element, arsenic （As）, in the stone-like coal deposits in southern Shaanxi＇s Qinba mountain area has posed carcinogenic endemic diSease linked to the coal -burning which gives off As. It is considered that release of the trace element As is related to not only its content but its speciation in coal. This article describes the experimpental study devoted to speciation of As in the stone-like coal, including sequential chemical extraction of As from coal and As release rate measurement. It is found that 75% of As in the coal is bound in sulfide, and distinct negative conelation exirsts between As release by burning coal and the residue form of As in the coal while a positive correlation exists berween As leaching rate and As sulfide as well as exchangeable AS in the stone-like coal.