The development of hardpan caps has great potential in rehabilitating sulfidic and metallic tailings, which may be accelerated by using exogenous Acidithiobacillus species. The present study aims to establish a bioaugmentation process with exogenous Acidithiobacillus species for accelerating the weathering of sulfidic minerals and formation of secondary mineral gels as precursors for hardpan structure development in a microcosm experiment. Exogenous Acidithiobacillus thiooxidans (ATCC 19377) and A. ferrooxidans (DSM 14882) were inoculated in a sulfidic Pb-Zn tailing containing negligible indigenous Acidithiobacillus species for accelerating the weathering of pyrite and metal sulfides. Microspectroscopic analysis revealed that the weathering of pyrite and biotite-like minerals was rapidly accelerated by exogenous Acidithiobacillus species, leading to the formation of secondary jarosite-like mineral gels and cemented profile in the tailings. Meanwhile, approximately 28% Zn liberated from Zn-rich minerals undergoing weathering was observed to be re-immobilized by Fe-rich secondary minerals such as jarosite-like mineral. Moreover, Pb-bearing minerals mostly remained undissolved, but approximately 30% Pb was immobilized by secondary Fe-rich minerals. The present findings revealed the critical role of exogenous Acidithiobacillus species in accelerating the precursory process of mineral weathering and secondary mineral formation for hardpan structure development in sulfidic Pb-Zn tailings.

硬盘帽的开发在修复硫化物和金属尾矿方面具有巨大潜力，可通过使用外源酸性硫杆菌种来加速。本研究旨在建立一种外源性嗜酸杆菌属细菌的生物强化过程，以加速硫化矿物的风化并形成次生矿物凝胶，作为微观实验中硬盘结构发展的前体。将外源性酸性硫硫杆菌（ATCC 19377）和铁氧化农杆菌（DSM 14882）接种在含有可忽略的本地酸性硫杆菌的硫化铅尾矿中促进黄铁矿和金属硫化物风化的物种。显微分析表明，外源酸性硫杆菌属物种迅速加速了黄铁矿和类黑云母矿物的风化，导致形成了次黄铁矿样矿物凝胶，并在尾矿中形成胶结轮廓。同时，观察到从经历风化的富含锌的矿物中释放的约28％的锌被富含铁的次生矿物如黄铁矿状矿物重新固定。此外，含Pb的矿物大部分仍未溶解，但约30％的Pb被次生的富含Fe的矿物固定化。目前的发现揭示了外源性酸性硫杆菌的关键作用 物种加速矿物风化和次级矿物形成的前体过程，从而促进硫化铅铅锌矿尾矿中硬壳结构的发育。