负载铜砷黄钾铁矾溶解转化及对重金属的制约机制

在金属硫化物矿区，黄钾铁矾作为典型的次生铁硫酸盐矿物，在形成和沉淀过程中会结合大量重金属。但随环境条件如pH、Eh改变，这些矿物会发生相转化，所负载的重金属将再次进入水体。本项目拟综合运用矿物地球化学、稳定同位素标记、溶解动力学等手段，重点研究黄钾铁矾溶解转化及重金属迁移机制。在此过程中的重金属形态变化及迁移，S2-的分馏及催化机制、重金属在矿物内部的分布及其黄钾铁矾转化过程中硫同位素的分馏特征等，揭示AMD成因铁硫酸盐次生矿物化学与生物转化机制及其所负载重金属的释放与再分配机制。研究成果将为理解重金属及次生矿物的地球化学行为及矿区修复策略提供理论基础。

Jarosite is a common mineral in acidic, sulfate-rich environments formed by the oxidation of sulfides, especially pyrite. It excellent reservoirs for toxic heavy metals as it are either sorbed or co-precipitated on the mineral phases. When environmental conditions change, phase transformation of these minerals will occur, causing redistribution or even releasing of bound heavy metals in the mining area. We propose this project to systematically study the geochemical processes that cause the dissolution and transformation of jarosite and reactivation of bound heavy metals in mining sites. We will use integrated methodologies including mineralogical approaches, stable S isotope methods, isotope fractionation to 1) investigate the key geochemical processes involving mineral stability and recrystallization, redistribution of heavy metals in different minerals in the presence, 2) observe the isotope distillation properties and catalytic mechanism of the S2- on the minerals in the process of phrase transformation, 3) elucidate the releasing and redistribution mechanism of loading heavy metals and the dissolution and transformation mechanism of jarosite. Those results could provide theoretical basis into the understanding of heavy metal and mineral behavior and remediation strategies for mining area pollution.