【作者】 陈敏；

【导师】 李小明；

【作者基本信息】 湖南大学 ， 环境工程， 2010， 硕士

【摘要】 锰是我国国民经济的重要矿产资源。在我国,锰矿资源虽然十分丰富,但富矿少,贫矿、复杂矿和细粒难选矿多,富矿资源目前严重短缺。微生物湿法冶金是一种利用微生物从矿物中提取有价金属的经济方法,特别适用于处理贫矿、表外矿及废矿,并具有成本低、投入小、能耗低、环境污染小等突出优点。因此研究微生物浸锰具有相当现实和重大的意义。本研究运用彭小伟等筛选出一株锰抗性强的细菌,对该细菌及其浸出电解锰废渣中的锰作了进一步研究。通过扫描电镜观察细菌形态、细菌DNA的提取及16SrDNA的PCR扩增等,对细菌作了进一步的鉴定；从锰渣及该细菌的特性出发,通过摇瓶试验对其浸锰条件进行了优化,考察了不同金属离子对其浸锰效果的影响,同时还对比了化学萃取与生物浸出的效果及其浸取前后锰渣中锰的形态变化。从电解锰废渣中筛选分离到的一株锰抗性强的细菌,菌落湿润,较小、较薄、较透明,菌落表面呈圆形,边缘整齐,稍隆起,无光泽,无鞭毛。基于16S rDNA分析,测序结果表明该细菌菌株为Serratia sp.(沙雷氏菌属),将其编号为Serratia sp.A1。利用Serratia sp.A1菌进行锰渣摇瓶浸出试验,探讨其最佳浸锰条件,试验结果表明在初始pH 6.0,固液比10%,温度37℃时,浸出效果最好,浸出率高达80.8%。分别加入不同浓度的Fe2+、Fe3+、Mg2+和Hg2+,研究其对Serratia sp.A1菌浸锰效果的影响。研究表明一定量的金属离子的加入均有利于Serratia sp. A1菌对锰的浸出,过量的金属离子的加入则会对锰的浸出起到抑制作用。加入Fe2+ 15g/L时比较经济适宜,分别加入Fe3+6g/L、Mg2+ 10g/L、Hg2+ 0.15g/L时,锰浸出效果最好,浸出率分别达到82.7%、65.1%和51.2%。采用优化的BCR(European Community Bureau of Reference)连续萃取方法对生物浸出前后锰的形态进行了分析。考察了3种萃取剂EDTA、HNO3和CaCl2对锰的萃取效果,对比发现Serratia sp.A1茵对锰的浸出能力较显著,3天后锰浸出率达79.7%,而3种化学萃取剂对锰的萃取效果为EDTA>HNO3>CaCl2,萃取率依次为54.4%,34.1%和23.1%,说明生物浸锰具有广阔的应用前景。化学萃取前后,酸溶解态锰所占比例均显著下降,残渣态锰所占比例均显著上升；生物浸出前后,酸溶解态和硫化物及有机结合态锰所占比例变化比较显著,分别由浸出前的34.2%和18.9%变至浸出后的16.1%和36.9%,说明浸出后电解锰废渣中的锰将以比较稳定和安全的形态存在,对环境危害性小更多还原

【Abstract】 Manganese is a kind of important mineral resource for our national economy. Manganese ore resources are rich in China, yet with fewer rich ores but more low-grade ores, complex ores and fine refractory ores. rich ore resources are in critical shortage presently. Microbiohydromtallurgy is a sort of economic method that utilizing microbe to extract valuable metals from minerals, which is particularly suitable for disposing low-grade ores, sub-marginal ores and spent ores and featuring merits like low cost, little investment, low energy consumption and little environmental pollution. Wherefore, it is of momentous practical significance for studying the bioleaching of manganese. In this study, a bacterium screened by Peng Xiaowei with strong manganese resistance was further studied, as well as the bioleaching of manganese in electrolytic manganese residue applying the bacterium. The characteristic of the bacterium was further identified by observing its phenotype with scanning electron microscope, extracting its DNA and PCR amplification of 16S rDNA; And the effect of different metal ions on manganese leaching rate was researched, as well as the optimized condition of bioleaching. Besides, the effect of chemistry extraction and bioleaching was contrasted as well as the variation in the binding forms of manganese before and after leaching. A bacterium of strong manganese resistance was screened from electrolytic manganese residue. The small round transparent colony is wet, thin, a little ridgy with regular edge and without flagellum or luster. Based on 16S rDNA, the sequencing result indicated that the bacteria strain is a species of Serratia sp., named as Serratia sp. A1.The shake-flask leaching experiments of manganese residue with serratia sp. Al indicated that the optimized condition of bioleaching was at initial pH value 6.0, solids concentration 10% and cultivated temperature 37℃,and when the leaching rate was up to 80.8%. To investigate the effect of metal ions on the bioleaching of serratia sp. A1, different concentrations of Fe2+, Fe3+, Mg2+ and Hg2+were put in the solution separately. The results showed that a given mass of metal ions were all in favor of the bioleaching, while superfluous metal ions would be inhibitory. It was economic and appropriate to add 15g/L of Fe2+, and the highest leaching rate of manganese was reached with 6g/L of Fe3+, 10g/L of Mg2+or 0.15g/L of Hg2+,up to 82.7%、65.1% and 51.2% respectively.The partitioning of manganese into different fractions was investigated before and after leaching by applying the sequential extraction procedures of the optimized European Community Bureau of Reference (BCR). Three kinds of extractant (EDTA, HN03 and CaCl2) were researched for manganese extraction, and compared with bioleaching, it was known that serratia sp.Al bacteria had a more prominent leaching ability with a manganese-leaching rate up to 79.7% after 3 days, while the rates of three chemistry extractants were 54.4%(EDTA), 34.1%(HNO3) and 23.1%(CaCl2) respectively, which indicated that bioleaching had a more extensive potential application. Before and after chemistry extraction, the proportion of manganese in acid-extraction fraction decreased prominently while the residual fraction increased. Before and after bioleaching, the proportion of manganese in acid-extraction and sulfide and organic matter/sulfide-bound fractions changed prominently, varied from 34.2% and 18.9% to 16.1% and 36.9% respectively, which showed that manganese in electrolytic manganese residue would stay in stable and nonbioavailable forms with low environmental hazard after leaching.更多还原