伴生放射性稀土渣资源化过程铀与钍的浸出特性及风险评估  

Leaching Characteristics and Risk Assessment of Uranium and Thorium in the Recycling Process of Associated Radioactive Rare Earth Slag

作　　者：罗明标[1] 董云雅 康长安 李烨玲 刘星宇 徐小江 LUO Mingbiao;DONG Yunya;KANG Chang’an;LI Yeling;LIU Xingyu;XU Xiaojiang(State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China)

机构地区：[1]东华理工大学核资源与环境国家重点实验室,江西南昌330013

出　　处：《东华理工大学学报(自然科学版)》2025年第1期84-93,共10页Journal of East China University of Technology(Natural Science)

基　　金：中国铀业有限公司东华理工大学核资源与环境国家重点实验室联合创新基金项目(NRE2021-16);国家环境保护重金属污染监测重点实验室开放基金项目(SKLMHM202215)。

摘　　要：我国伴生放射性稀土废渣大量堆存,所含放射性源头U、Th易释放进入生态系统,隐患巨大,废渣的综合利用研究迫在眉睫。以江西某稀土冶炼厂堆存的伴生放射性稀土酸溶渣为研究对象,将部分废渣用作水泥生料,再烧制成熟料,分析稀土渣和水泥熟料中放射性U、Th的浸出特性及产生的环境风险。结果表明,酸溶渣中U、Th浸出毒性超标,对环境危害大,制成熟料后,U、Th的浸出毒性满足国标《稀土工业污染物排放标准》限值。BCR形态提取结果表明,高温烧制有利于U、Th的形态向残渣态转化,迁移性显著降低。U、Th的浸出含量随浸提剂酸度增大、浸泡时间延长而增加,在浸提剂pH值为2.0时,酸溶渣中U、Th浸出质量浓度远高于国标规定的限值,而熟料中的浸出质量浓度则远小于国标限值。地累积指数和潜在生态风险指数结果表明,酸溶渣中U、Th产生混合极重度污染,风险水平为高风险,掺渣比例≤1.5%的熟料中U、Th浸出含量小,潜在生态风险水平较低,内外照射指数皆小于1。China’s associated radioactive rare earth waste residue is piled up in large quantities,and the radio-active sources U and Th are easy to release into the ecosystem.The hidden dangers are huge,and the comprehen-sive utilization of waste residue is imminent.The associated radioactive rare earth acidsoluble slag stored in a rare earth smelter in Jiangxi Province is taken as the research object.Some of the waste slag is used as cement raw ma-terial,and then fired into mature material.The leaching characteristics and environmental risks of radioactive U and Th in rare earth slag and cement clinker are analyzed.The results show that the leaching toxicity of U and Th in acid soluble slag exceeds the standard,which is harmful to the environment.After being made into clinker,the leaching toxicity of U and Th meets the limit value of GB“Emission Standard of Pollutants for Rare Earth Indus-try”.The results of BCR morphology extraction showed that high temperature firing was beneficial to the transfor-mation of U and Th to the residual state,and the mobility was significantly reduced.The leaching content of U and Th increases with the increase of the acidity of the extractant and the extension of the soaking time.When the pH value of the extractant is 2.0,the leaching mass concentration of U and Th in the acid-soluble slag is much higher than the specified limit value,while the leaching mass concentration in the clinker is much smaller than the standard limit.The results of the geo-accumulation index and potential ecological risk index showed that U and Th in acid soluble slag produced mixed extremely severe pollution,and the risk level was high.The leaching content of U and Th in clinker with a slag ratio≤1.5%was small,the potential ecological risk level was low,and the in-ternal and external exposure indexes were all less than 1.

关 键 词：稀土酸溶渣 资源化 铀 钍 环境风险评估 

分 类 号：X705[环境科学与工程—环境工程]