外源硫和Fe^(3+)对低硫铀矿生物浸出的影响

Influence of Exogenous Sulfur and Fe^(3+) on Bioleaching of Low-sulfur Uranium Ore

针对铁、硫含量较低的铀矿,采用外源添加不同浓度的Fe^(3+)及单质硫的方法强化铀矿生物浸出,研究外源Fe^(3+)、单质硫对浸出体系中pH、氧化还原电位值Eh、铁离子浓度、铀浓度的影响。结果表明,Fe^(3+)初始浓度分别为0、1、2、3和4g/L时,铀浸出率分别为81.85%、92.61%、89.15%、86.28%和86.09%,Fe^(3+)浓度为1g/L时浸出铀浓度最大,不同初始浓度的Fe^(3+)对铀矿浸出具有显著影响。在2g/L Fe^(3+)体系中,添加2g/L单质硫与未添加单质硫相比,pH上升较慢,铀浸出率提高1.63个百分点;SEM-EDS分析表明,与原矿相比,铁体系中矿物表面粗糙且矿石结构疏散,矿石颗粒比表面积增加,浸出渣样中伴随黄钾铁矾等沉淀的产生,添加2g/L单质硫的体系中黄钾铁矾显著降低。

In order to enhance uranium bioleaching of low-iron and low-sulfur uranium ore,adding different concentrations of Fe^(3+)and elemental sulfur was applied to improve uranium bioleaching rate.Effects of different concentrations of Fe^(3+)and elemental sulfur on pH value,Eh value,Fe^(3+)concentration,and uranium concentration during uranium leaching were investigated.The results show that different initial concentration of Fe^(3+)has a significant impact on uranium leaching rate.Uranium leaching rate is 81.85%,92.61%,89.15%,86.28%and 86.09%respectively with 0g/L,1,2,3 and 4g/L Fe^(3+)addition.The optimum uranium leaching condition is 1g/L of Fe^(3+)addition.Furthermore,in 2g/L Fe^(3+)system,pH value of 2g/L elemental sulfur system rises slower than that without elemental sulfur.Leaching rate of uranium in elemental sulfur system obviously rises by 1.63percent points.SEM-EDS analysis show that specific surface area of ore particles rises due to rough surface of mineral and evacuation of ore structure after bioleaching.Jarosite precipitation is also found in leaching residue;however,jarosite precipitation on surface of uranium ore is obviously reduced in 2g/L elemental sulfur system.