控制砂岩型铀矿床中铀迁移转化的主要水文地球化学作用实验

采集中国北方某砂岩型铀矿床中的含铀矿石样品,共进行7组土柱模拟实验,分别探究氧化-还原条件、HCO-3浓度、有机质和微生物对铀迁移转化的影响。结果表明:氧化-还原条件改变对铀迁移转化会产生重要影响,含氧入渗水带来的氧化环境使含水介质中沉淀态铀大量氧化溶解;HCO-3的促解吸作用及铀酰络合物的强迁移能力对地下水中铀迁移转化影响较大;有机质会参与含水介质中矿物吸附点位竞争,从而造成铀的解吸;微生物作为氧化-还原反应的催化剂,在氧化剂氧化沉淀态铀的反应中起重要作用;氧化作用、解吸作用和溶解作用对地下水中铀迁移转化的贡献比例分别为65.28%、23.91%和10.81%。

Experiment on Hydrogeochemical Effects Affecting Uranium Migration and Transformation in Sandstone-type Uranium Deposit

Seven sets of indoor soil column simulation experiments of uranium-containing ore samples from sandstone-type uranium deposit in the northern China were carried out,and the effects of redox conditions,HCO-3 concentration,organic matter and microorganisms on uranium migration and transformation were investigated.The results show that the changes of redox conditions have an important impact on uranium migration and transformation,the oxidizing environment brought by the infiltration of oxygenated water can cause a large amount of sedimentary uranium oxidation and dissolution in aqueous medium;the promoting desorption of HCO-3 and the strong migration ability of uranyl complexes have a great impact on uranium migration and transformation in groundwater;the organic matter can participate in the competition of mineral adsorption sites in aqueous medium,which causes the desorption of uranium;the microbes as catalysts for redox reactions play an important role in the oxidation of sedimentary uranium;the contribution ratios of the oxidation,desorption and dissolution to uranium migration and transformation in groundwater are 65.28%,23.91% and 10.81%,respectively.