沥青铀矿石细菌浸出机理的实验研究

Experimental Studies on Bacteria Leaching Mechanism of Uranium from Uraninite

采用氧化亚铁硫杆菌作为实验菌,针对有菌有Fe2+、有菌无铁、无菌有Fe3+、无菌有Fe2+、不控制pH值的无菌无铁和pH值控制在2.0的无菌无铁6种沥青铀矿石浸出体系,考察了浸出过程中细菌的浓度、溶液pH值、电位、亚铁离子浓度、全铁离子、铀浓度等参数的变化,得到铀矿石的浸出率分别为98.00%,80.33%,97.66%,93.00%,20.33%,72.00%.结果表明,在沥青铀矿石的细菌浸出中,细菌的作用以间接作用为主,即细菌把还原态的硫或单质硫及Fe2+氧化成Fe2(SO4)3.由于Fe2(SO4)3是一种强氧化剂,将不溶的U(IV)氧化为可溶解的U(VI),从而使沥青铀矿石中的铀得以浸出.

Thiobacillusferrooxidans was used in bacteria leaching of uranium from uraninite ore leaching system with bacteria and Fe^2＋, the system with bacteria and without Fe^2＋, the system with Fe^2＋ and without bacteria, the system with Fe^3＋ and without bacteria, the system without bacteria and iron ions, and uncontrolled pH value, and the system without bacteria and iron ions, and controlled pH value of 2. The effects ofpH value, redox potential （Eh）, ferrous ions, total iron and uranium concentration were examined. The leaching rates for the six uraninite ore leaching systems reached 98.00%, 80.33%, 97.66%, 93.00%, 20.33% and 72.00%, respectively. The results show that bacteria play mainly an indirect role in leaching uranium from uraninite. That is to say that bacteria oxidize sulfate in reduction state, So Fe^2＋ to produce Fe2（SO4）3 and it in turn oxidizes the insoluble U（Ⅳ） to soluble U（Ⅵ） and, in this way, the uranium in uraninite ore is leached out.