煤炭洗选中有害痕量元素的迁移与脱除

对3个大型洗煤厂的原煤和相应的洗选产物进行了现场采样分析,通过测定原煤和各洗选产物中痕量元素的含量,研究了As,Be,Cd,Co,Cr,Hg,Mn,Ni,Pb,Sb和Se等11种有害痕量元素在洗煤过程中的迁移与脱除规律。结果表明,常规物理洗选能有效脱除煤中的无机矿物组分,在降低精煤灰分和硫分含量的同时,精煤中有害痕量元素也得到一定的脱除,除Se的脱除率较低以外(13.3%),其他元素的脱除率都在20%以上,这主要是由于这些痕量元素随着伴生的无机矿物被脱除;洗选后Be,Cd,Co,Cr,Hg,Mn,Ni主要向矸石中富集,Se则主要在中煤里富集,As,Pb和Sb在不同洗选产物中的分布则较为复杂。

Migration and removal of toxic trace elements during coal washing

Coal washing，which has been widely applied，is an economical and effective way to reduce the emission of pollutants caused by coal combustion.In this study，the onsite sampling and analysis of raw coals and related products from three large-scale coal washing plants were conducted.By measuring the contents of trace elements in raw coals and coal washing products，the migration and removal of some toxic trace elements during coal washing were studied，which included As，Be，Cd，Co，Cr，Hg，Mn，Ni，Pb，Sb and Se.The results show that the conventional physical coal washing technology could effectively remove the inorganic mineral components in coal.The toxic trace elements in the cleaned coal can be partially removed with the decrease of ash yield and sulfur content.The removal ratios of all trace elements were above 20% except Se (13.3%).This is mainly due to the removal of trace elements with the associated minerals.Be，Cd，Co，Cr，Hg，Mn and Ni removed during coal washing would mainly be enriched in gangue while Se mainly went into middling coal.The distribution of As，Pb and Sb in the products of coal washing was complicated.