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STUDY ON UNUSUALSORPTION OF URANIUM ONTO BIOTITE

铀在黑云母上异常吸附的研究

基本信息

批准号：
10680491
负责人：
IDEMITSU Kazuya
金额：
$ 2.37万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10680491/
关键词：
Uranium Biotite Unusual Sorption Acidity Constant pH dependence Desorption Specific Area PZC PH依存性ウラン化学種

项目摘要

Experiments on the sorption of U(VI) on a biotite were carried out in the atmospheres of air and 1 atm of COィイD22ィエD2 over a wide range of pH to understand the fundamental controls on uranium sorption on biotite minerals. Biotite powder (mesh 32 - 60) were washed with 1N HCl for a week and were rinsed twice with deionized water for a week. This HCl treatment was necessary to avoid the effects by other minerals. The uranium solutions were prepared from ィイD2233ィエD2UOィイD22ィエD2 regent by dissolving into nitric acid and then adjusted at a pH of interest with the initial concentration of 4.8 x 10ィイD1-6ィエD1 M. The concentration of uranium and pH in each solution were measured at regular time intervals before and after adding some biotite powder. The peak Kd values in air and COィイD22ィエD2 were higher than 100 ml/g around pH 6 and approximately 2 ml/g around pH 5, respectively. A comparison of aqueous uranium speciations and sorption results indicates that neutral uranyl hydroxide could be an important species sorbed on the biotite in both atmospheres. Sequential desorption experiments with KCl and nitric acid solutions were also carried out after sorption experiments to investigate sorption forms of uranium. Several percent of uranium in solution was sorbed on the biotite as an exchangeable ion with potassium. The fraction of exchangeable uranium had a little dependence on pH. Approximately 50% of uranium sorbed on the biotite was extracted by 1N of nitric acid. The other uranium could not be extracted even by 1N HNOィイD23ィエD2 solution. It is possible that most of the uranium could be reduced from U(VI) to U(IV) via Fe(II) on the biotite surface after sorption.

为了了解铀在黑云母矿物上吸附的基本控制因素，在空气和1 atm CO_（22）O用1 N HCl洗涤黑云母粉末（32 - 60目）一周，并用去离子水冲洗两次，持续一周。这种盐酸处理是必要的，以避免其他矿物质的影响。铀溶液是通过溶解在硝酸中，然后调节到目标pH值，初始浓度为4.8 × 10 -6 mol/L D1-M，从氯化物D2233氯化物D2 UO氯化物D22氯化物D2试剂制备的。在加入一些黑云母粉末之前和之后，以固定的时间间隔测量每种溶液中的铀浓度和pH。在空气和CO_2介质中，pH值为6时的Kd值大于100 ml/g，pH值为5时的Kd值约为2 ml/g。水溶液中铀的形态和吸附结果的比较表明，中性氢氧化铀酰可能是一个重要的物种吸附在黑云母在这两种气氛。在吸附实验之后，还进行了KCl和硝酸溶液的连续解吸实验，以研究铀的吸附形式。溶液中的铀有百分之几以可与钾离子交换的形式吸附在黑云母上。交换性铀的分数有一点依赖于pH值。约50%的吸附在黑云母的铀被提取的1 N的硝酸。其它铀甚至不能用1 N HNO_3 ~（2-）D_3 ~（2-）D_2溶液萃取。吸附后，大部分铀可能通过Fe（II）在黑云母表面被还原为U（IV）。