稀土冶炼过程中铀、钍、镭等放射性核素的迁移

The Migration of U,Th,Ra during the Smelting of Rare Earth

研究了天然放射性元素钍、铀、镭在稀土冶炼过程中转移情况。使用X-射线荧光（XRF）对渣样分析以及电感耦合高频等离子光谱仪（ICP）对冶炼过程产生的水样分析,结果表明,得到稀土矿中的钍、镭元素主要富集于酸溶渣;铀元素富集于中和渣。通过伽马谱分析计算酸溶渣中钍含量为426.47 mg/kg,中和渣中铀的含量为281.82 mg/kg;并且酸溶渣的放射性活度要高于中和渣。最后分析稀土生产工艺流程得到渣中的主要物相组成：酸溶渣中主要含有硫酸钡、二氧化硅、稀土难溶氧化物和稀土复盐;钍元素以二氧化钍、磷酸钍、镭元素以硫酸镭等难溶盐的形式富集于酸溶渣。中和渣中主要含草酸钙、氯化钠、少量碳酸盐和稀土草酸盐;铀元素以重铀酸盐、氢氧化四铀的形式富集于中和渣。

The transfer of thorium,uranium and radium in rare earth smelting process was explored in this paper. XRF and ICP were used to determine the composition of the tailing and content of thorium and uranium in wastewater,respectively.The results reflected that the Th and Ra were concentrated in acid leaching residue,but U was concentrated in neutralization tailing. The results of Gamma spectrometer suggested that the concentrations of Th in acid leaching residue was 426. 47 mg/kg,and the content of U in neutralization residue was 281. 82 mg/kg. Moreover,the radioactivity of acid leaching residue was higher than neutralization tailing. The acid leaching residue is mainly consists of Ba（SO4）,Si O2,insoluble rare earth oxides and complex salt of rare earth. The neutralization residue is mainly consists of Ca C2 O4,Na Cl,carbonate and oxalate of rare earth. Thorium and radium are enriched in acid leaching residue in the forms of Th O2,Th3（PO4）4 and Ra SO4. Uranium is enriched in neutralization residue in the forms of U（OH）4 and diuranate.