铁氧化细菌的分离及其浸出钼镍尾矿试验

从钼镍矿区矿坑废水中分离出1株嗜酸性硫杆菌,通过对该菌株形态及理化特征检测分析,初步鉴定为氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,A.f菌)。以FeSO_4·7H_2O和钼镍尾矿作为能量来源对其驯化培养,并利用驯化与非驯化的A.f菌进行摇瓶浸出钼镍尾矿试验。结果表明,驯化后的A.f菌更有利于尾矿中金属的浸出,4种目标金属浸出率大小顺序为NiZnAsMo,钼镍尾矿中Ni、Mo、Zn、As在驯化细菌作用下最大浸出率分别为62.41%、55.66%、41.87%、12.04%,比非驯化组高2~8个百分点;A.f菌浸矿过程中,存在细菌对矿物的直接作用机理及细菌产生的H~+、Fe~(3+)对矿物的间接作用机理,H~+在尾矿Ni、Zn的浸出中占主导作用,而As、Mo的浸出主要依靠Fe~(3+)对矿物的持续氧化作用。

Isolation of Iron Oxidization Bacterium and Bioleaching from Ni-Mo Tailings

One acidophilic thiobacillus bacterium isolated from acid mine drainage of nickel-molybdenum was identified as Acidithiobacillus ferrooxidans (A.f) by morphological and physiological characteristics analysis. It was domesticated applying Ni-Mo ore tailings and FeSO4?7H2O as energy sources. Bioleaching of Ni-Mo ore tailings with domesticated and non-domesticated A.f was carried out in shake flasks. The results show that domesticated A.f was more conducive to leaching metals from tailings, the sequence of leaching rate of four target metals is Ni>Zn>As>Mo with the maximum extraction rate of 62.41%, 55.66%, 41.87%, and 12.04%, which is 2~8 percent point higher than that of non-acclimated group. The bioleaching mechanisms were attributed to be oxidation by bacterial and chemical solubilization by microbially-produced H and Fe3 . H plays a dominant role in leaching of Ni and Zn from tailings, while leaching of As and Mo mainly relies on continued oxidation by Fe3 .