基于铀矿中本源硫杆菌对黄铁矿和铀矿浸出的协同作用

研究砂岩型铀矿床中本源嗜酸性氧化亚铁硫杆菌（Acidithiobacillus ferrooxidans, At.f）、嗜酸性氧化硫硫杆菌（Acidithiobacillus thiooxidans，At.t）对黄铁矿及铀矿浸出的协同作用。采用富集培养法、无机盐硅酸钠平板法对砂岩型铀矿中的硫杆菌分离纯化，通过分析菌株的形态学特征、生理生化结果及16S rDNA序列确定菌株的系统发育地位，并利用摇瓶培养法设计浸矿试验，向黄铁矿浸出体系中分别加入分离纯化的At.f、At.t及混合的At.f和At.t，检测pH值、氧化还原电位值（Eh值)的变化，浸矿40 d，测定浸矿体系的总铁离子浓度和硫酸根离子浓度，并分析黄铁矿矿渣表面形态及成分。根据黄铁矿的浸出结果，设计铀矿浸出试验，浸矿40 d，测定浸出体系中的pH值、Eh值、总铁离子浓度、硫酸根离子浓度等参数并计算四价铀的浸出率。结果表明，分离的两株优势菌中SW-2鉴定为嗜酸性氧化亚铁硫杆菌(At.f)，SW-3鉴定为嗜酸性氧化硫硫杆菌(At.t)。At.f、At.t浸出黄铁矿和铀矿时存在协同作用，At.f为浸矿体系的强氧化剂，主要将Fe2+氧化成Fe3+，Fe3+将UO2氧化成可溶性的UO22+；At.t可为浸矿体系提供酸性环境；At.f: At.t = 5:1试验组对黄铁矿和铀矿的浸矿效果最好，四价铀的浸出率为55.60%，黄铁矿矿渣表面形态显示细菌对黄铁矿存在直接的氧化作用；At.f、At.t高效浸出黄铁矿的菌量比例对以黄铁矿为伴生矿的铀矿的细菌浸出也具有明显的促进作用，研究结果可以为工业微生物浸铀时提供一定的支持并为以黄铁矿为伴生矿的其他矿物的微生物浸出提供参考。

Synergism effect on leaching pyrite and uranium ore by thiobacillus in sandstone type uranium ore

The main purpose of this experiment is to do research on the synergism effect on leaching uranium ore and pyrite by Acidithiobacillus ferrooxidans(At.f) and Acidithiobacillus thiooxidans(At.t). The authors separate and purificate the thiobacillus of sandstone type uranium deposit by the method of enrichment culture, inorganic salt sodium silicate tablet. Through the analysis of the morphological characteristics, physiological and biochemical results of strain and 16s rDNA sequence, the strain status in system development are determined. And by using the method of shake flask culture design ore leaching test, added separated and purified At.f and At.t and mixed At.f and At.t to pyrite leaching system respectively. Measured the change of parameters such as pH, Eh. 40 d later, detected total concentration of iron and sulfate’s ion. meanwhile analyzed the composition and morphology of the surface of slag of pyrite. Designing the uranium leaching experiment based on the results of the leaching of pyrite, after 40 d, Measured the change of parameters such as pH, Eh, total concentration of iron and sulfate’s ion, calculated the leaching rate of tetravalent uranium. The results showed: SW-2 is identified as At.f, SW-3 was identified as At.t. At.f and At.t exisited synergy leaching pyrite and uranium ore, At.f was strong oxidant by oxidizing Fe2+ to Fe3+ before Fe3+ oxidizing UO2 to soluble UO22+ in leaching system. At.t could provide acidic environment for leaching system, the best amount combination of bacteria was 5:1(At.f:At.t), the leaching rate of UO2 was 55.60%, surface morphology of slag of pyrite showed that was a direct oxidation from the bacterial to pyrite. The condition of At.f and At.t that leaching pyrite also had the same significant role in promoting microbiological leaching uranium ore with pyrite as the associated minerals. The results of the study could provide certain support for industrial microbial leaching uranium and provide reference for microbiological leaching minerals with pyrite as the associated minerals.