功能菌群耦合黄铁矿浸出软锰矿的研究

Study of coupled pyrite leached pyrolusite by functional microflora

摘要:

【目的】将3种不同来源的环境样品混合后接种至含1%黄铁矿和1%软锰矿的培养基中进行富集培养, 初步得到有一定浸矿功能的混合微生物菌群。【方法】菌群继续用于黄铁矿和低品位软锰矿共同浸出, 设置未接种的体系作为对照。【结果】对浸出过程中菌群结构的变化、pH、锰浸出率和浸出残渣的成分进行分析, 结果发现接种过微生物菌群的浸出体系在反应15 d后, 锰浸出率达到92.48%, 远高于未接菌对照组的40.34%; 菌群中Thiomonas sp. 所占比例从最初的2%上升到浸出结束时的93%。实验组的pH从最初的4.0下降到2.5; X射线衍射(XRD)分析发现, 通过生物作用浸出的残渣中含有黄钾铁矾, 说明生物代谢产生了大量的硫酸。【结论】证明微生物在两矿浸出过程中通过促进黄铁矿解离, 维持体系低pH等作用加速反应的进行。结果为进一步研究微生物浸矿的作用机制和开发低品位锰矿的生物浸出工艺打下了基础。

关键词:混合功能菌群, 黄铁矿, 软锰矿, 细菌浸出, 16S rRNA基因文库

Abstract:

[Objective] Three different environmental samples were mixed and inoculated into 100 mL fresh medium containing 1% pyrolusite and 1% pyrite. After enrichment we got bioleaching microflora. [Methods] Obtained microorganism consortia were used to leach pyrite and low-grade pyrolusite. Non-inoculation system was conducted as control group. [Results] Series of parameter were monitored during the process, including dynamic of consortia construction, pH value, leaching ratio of manganese, and XRD analyze of leaching residual. Leaching ratio of manganese was 92.48% after 15 days cultivation. And it was much higher than control group (40.34%). Within microbial consortia, Thiomonas sp. was the dominant species and its proportion increased from 2% to 93% of the consortia. Value of pH was declined from 4.0 to 2.5 in experimental group. Jarosite was observed in bioleaching residual. [Conclusion] Decrease of pH value and formation of jarosite indicated abundant sulfuric acid produced by bacterial metabolism. Result suggested that increasing bioleaching ratio of pyrite and pyrolusite due to dissociation of pyrite and decline of pH value by bacterial activity. This study could provide the basis for the further research of bioleaching mechanism and improvement of industrial art of low-manganese ore mineral resource.

Key words:Microorganism consortia, Pyrite, Pyrolusite, Bioleaching, 16S rRNA clone library