摘要
采用不同Fe^(3+)浓度的酸性溶液,对取自新疆伊犁盆地的砂岩铀矿石进行了溶浸对比试验,探讨了铀在酸性含Fe^(3+)溶液作用下的溶解迁移动力学特征及其与Fe^(3+)的关系。结果表明,在Fe^(3+)的氧化作用下,铀从矿石向溶液的迁移于10小时内快速达到平衡,溶解速度衰减迅速;铀的溶解速度与Fe^(3+)向Fe^(2+)转化速度呈正相关的指数函数关系,当Fe^(3+)向Fe^(2+)转化速度趋近零时,铀的氧化溶解基本停止,溶液中的铀达到平衡浓度;Fe^(3+)向Fe^(2+)浓度达到2g/L可使铀强烈溶解迁移,而溶液酸度增高会弱化铀溶解速度与Fe^(3+)转换速度的关系,但酸度在2g/L^4g/L(对应pH值1.65~1.33)之间变化不会对铀的浸出产生显著影响;保持Fe^(3+)浓度为2g/L、酸度为2g/L(pH值1.65)的水化学条件对铀的溶浸是经济且足够有效的。
To study themigration kinetics of uranium driven by dissolved ferric iron in acid solution, a group of leaching tests on the sandstone-type uranium ore taken from the Yili Basin had been carried out with sulfuric acid solution containing different contents of ferric iron. Results show that uranium, oxidized by ferric iron, can migrate from ore to the solution within 10 hours. The migration rate declines rapidly so that it makes uranium dissolution process gets to an equilibrium stage. The rate of uranium dissolution positively correlates with that of the transformation between ferric iron and ferrous iron as exponential functions. While the transformation rate of ferric iron to ferrous iron approaches zero, the uranium oxidation process stops and then leads to an uranium dissolution equilibrium. It also shows that ferric iron concentration of 2g/L is sufficient to induce a strong dissolution of uranium migration from ore. The increasing of the solution acidity weakens the relationship between uranium dissolution rate and Fea+ conversion rate. However, when acidity changes from 2g/L to 4g/L (pH value of 1. 65 - 1. 33), the uranium leaching effect does not change significantly. So, the solution with Fe3+ concentration of 2g/L and the acidity of 2g/L (pH value of 1.65) is economical and effective for uranium leaching.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2016年第12期3554-3562,共9页
Acta Geologica Sinica
基金
国家重点基础研究发展计划(973)项目(2015CB453002)
国家自然科学基金项目(41572231)
江西省重点研发计划项目(20161BBH80051)资助的成果
关键词
砂岩铀矿
三价铁离子
氧化作用
铀迁移
sandstone type uranium ore
ferric iron
oxidization
uranium migration