Behavior and environmental impacts of radionuclides during the hydrometallurgy of calcareous and argillaceous rocks, southwestern Sinai, Egypt

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• 作者：Ibrahim E. El Aassy^a ; Afaf A. Nada^b ; ^{afafhero_nada@yahoo.com} ; ^{afafhero_nada@asunet.shams.edu.eg} ; Mohamed M. El Galy^a ; Mohamed G. El Feky^a ; Thanaa M. Abd El Maksoud^b ; Shadia M. Talaat^b ; Eman M. Ibrahim^a
• 关键词：Hydrometallurgy ; Radionuclides ; Southwestern Sinai
• 刊名：Applied Radiation and Isotopes
• 出版年：2012
• 期刊代码：6_09698043
• 类别：ce
• 出版时间：June, 2012
• 卷：70
• 期：6
• 页码：1024-1033
• 文件大小：1002 K

摘要

The hydrometallurgy of radionuclides means getting the radioelements from the rocks into solution by leaching, getting the radionuclides from the solution by extraction process, and then precipitation of the desired elements to obtain concentrate. The follow-up of the radionuclides during these processes is the main target of this work to identify the identity of the original samples, pregnant solutions (leachates), residuals and the concentrate.

Six samples were chosen to achieve this work. The leaching process was carried out under the conditions; 20-30%acid (H₂SO₄) concentration, 1:3 solid/liquid ratios, 60 min stirring time at room temperature. The activity concentrations of ²³⁸U, ²³⁵U, ²³⁴U, ²²⁶Ra, ²¹⁴Pb, ²¹⁴Bi, ²³²Th and ⁴⁰K were measured in the original samples, residuals and U-concentrate (Bq/kg), and leachates (Bq/鈩?.

The results indicate that, the radionuclides before ²²⁶Ra in the ²³⁸U decay series are more leachable (released) than those from ²²⁶Ra to ²¹⁴Bi in the order; ²³⁴U>²³⁸U=²³⁵U 鈮?²²⁶Ra>²¹⁴Pb>²¹⁴Bi. ²³²Th and ⁴⁰K are immobile under the present conditions. The radiological hazards of natural radioactivity in the original samples, leachates, residuals and U-concentrate were calculated and compared with the internationally recommended values and were found to be much higher than the world average values.