方解石处理酸性矿排水次生矿物学和渗透性的研究

Experimental study on secondary mineralogy and permeability during treatment acid mine drainage using calcite

采用批实验和柱长期运行实验研究方解石处理酸性矿排水中次生矿物学和渗透性问题,扫描电镜(SEM)和傅里叶红光谱(FTIR)结果揭示方解石包覆层包括两层,内层为结晶石膏层,外层为纤铁矿层,后变为针铁矿;通过费克第一定律建立包覆下的溶解模型,ρ(Ca2+)=At1/2+B,其A值与包覆层石膏比例(fgyp)平方成反比;柱实验结果揭示渗透系数变化是一个突变过程,长期处理中外层的Fe系包覆层是引起堵塞的关键。

The secondary mineralogy and permeability variation were studied by batch and long-term column experiments during treatment of acid mine drainage using calcite, the characteristic peaks of infrared spectra and images of scanning electron microscope reveal that the calcite surface has two coating layers, the internal layer is crystalline gypsum, the external layer is lepidocrocite, which can gradually change into goethite. The model of releasing calcium ion on coating surface of calcite was established by Fick＇ s first law ,p （ Ca^2＋） = At^1/2 ＋B, the result shows that a value is inversely proportional to square of proportion of gypsum in coating layer （fgyp）. The result of column experiment shows that the permeability variation is catastrophe process, the coating layer of iron is a key factor of clogging during longterm treatment.