砷黄铁矿产酸和中和过程中释砷规律及主动钝化研究

Arsenopyrite is the leading cause of arsenic-polluted acid mine drainage (AMD). Based on production and treatment processes of AMD, the release rules of arsenic will be investigated, specifically, the internal and external factors mainly controlling rules, the constraints of secondary mineralization and development of naturally coatings on arsenic release and their mechanisms will be analyzed systematically, arsenic transfer and control problems on mineral-coating-water also will be explored scientifically. In addition, the arsenic release dynamic models under coating and no coating will be built, the differences of release capacities and ways between two processes will be compared further. Based on these, a novel low-cost phosphate iron basis passivation technique will be studied aiming at solving arsenic release and acid production problems, the corresponding mechanism and performance of long-term controlling acid productin and inhibiting arsenic release of naturally coating and passivation layer will be investigated and compared,the development charateristics and passivation mechanism will be revealed. These scientific achievements not only can deepen understand on arsenic origin and fate of AMD, but also provide theoretic foundation for in situ passivation treatment of arsenic-containing sulfides tailing.

砷黄铁矿是酸矿废水（AMD）As污染最主要元凶。本项目以AMD产生和处理两大基本过程为背景，开展产酸和中和过程释As规律研究，系统调查内外主控因素、次生矿化、天然包覆层发育等对矿物释As制约及作用机制，探讨As在"矿物-新生界面层-水"之间的转移和控制问题，建立有无包覆层的释As动力学模型，并进一步比较两过程下释As量变和途径差异；在此基础上，以骨炭作为缓释磷源，开展低成本磷基铁膜主动钝化研究，调查长时间尺度下天然包覆层和主动钝化层在控酸和滞As上的作用效果和机制，深入揭示钝化层发育特征及钝化机理。其成果不仅能够丰富AMD中As起源及归趋认识，而且为含As硫化物尾矿原位钝化处理提供理论依据。

项目以砷黄铁释放砷动力学为研究背景，主要研究砷黄铁矿自然溶解过程下砷铁释放，同时开展磷基铁膜钝化砷黄铁矿研究，以湖南和四川砷尾矿进行相关对比调查。通过本项目发现：1）砷黄铁矿自然溶解过程，由于铁的沉淀，会引起砷开始释放增加，而后砷显著减少；2）磷基铁膜钝化砷，由于碱性较高，反而会引起砷的释放，但对含砷尾矿其它重金属Pb和Zn钝化效果明显；3）还原微生物（嗜酸铁还原菌JF-5）的存在对次生含砷铁矿的释砷效果明显，尤其是氧化还原更替阶段；4）砷和磷分子结构对于矿化砷有着影响，可以形成磷/砷氯铅矿；5）还原微生物（SRB）能够与嗜酸铁还原菌（JF-5）形成纳米四方硫铁矿这一次生矿物，它能够显著提高对砷的释放，以此为纳米包覆层，能够显著提高酸矿废水中砷的去除。