检索结果-南通市图书馆

uranium speciation in coal bottom ash investigated via X-ray absorption fine structure and X-ray photoelectron spectra

引用

Journal of Environmental Sciences 2018年第12期30卷 88-94页

作者： Yinglong Sun Menxin Wu Lirong Zheng Bangda Wang Yi Wang National Meteorological Center China Meteorological Administration Key Laboratory for Solid Waste Management and Environment Safety Ministry of Education of China Tsinghua University Beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences

Similar to chromium contamination, the environmental contamination caused by uranium in radioactive coal bottom ash（CBA） is primarily dependent on the chemical speciation of uranium. However, the relationship between uranium speciation and environmental contamination has not been adequately studied. To determine the relationship between uranium speciation and environmental contamination, X-ray absorption fine structure（XAFS） and X-ray photoelectron spectra（XPS） analyses were performed to determine the uranium speciation in CBA exposed to different chemical environments and simulated natural environments. The leachability of the different forms of uranium in the CBA was studied via a simulated acid rain leaching experiment, and the results showed that 57.0% of the total uranium was leached out as U（VI）. The results of a linear combination fit（LCF）of the X-ray absorption near edge structure（XANES） spectrum revealed that in the raw CBA, the uranium mainly occurred as U_3O_8（71.8%）. However, in the iron-rich particles, the uranium mainly occurred as UO_2（91.9%） after magnetic separation. Magnetite is a ubiquitous ferrousbearing oxide, and it was effective for the sorption of U（IV）. The result of FeSO_4 leaching experiment indicated that 96.57% of total uranium was reduced from U（VI） to U（IV） when infiltrated with the FeSO_4 solution for 6 months. This result clearly demonstrated the changes in chemical valence of uranium in the coal ash and provided a conceptual principle for preventing uranium migration from ash to the surrounding soil and plants.

关键词： Coal bottom ash uranium speciation XAFS uranium migration

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Permeability evolution mechanism and the optimum permeability determination of uranium leaching from low-permeability sandstone treated with low-frequency vibration

引用

Journal of Rock Mechanics and Geotechnical Engineering 2023年第10期15卷 2597-2610页

作者： Yong Zhao Xiqi Li Lin Lei Ling Chen Zhiping Luo School of Resource Environment and Safety Engineering University of South ChinaHengyang421001China Department of Nuclear Safety China Institute of Atomic EnergyBeijing102413China

Low-frequency vibrations can effectively improve natural sandstone permeability,and higher vibration frequency is associated with larger ***,the optimum permeability and permeability evolution mechanism for uranium leaching and the relationship between permeability and the change of chemical reactive rate affecting uranium leaching have not been *** solve the above problems,in this study,identical homogeneous sandstone samples were selected to simulate lowpermeability sandstone;a permeability evolution model considering the combined action of vibration stress,pore water pressure,water flow impact force,and chemical erosion was established;and vibration leaching experiments were performed to test the model *** the permeability and chemical reactions were found to simultaneously restrict U6þleaching,and the vibration treatment increased the permeability,causing the U6þleaching reaction to no longer be diffusion-constrained but to be primarily controlled by the reaction *** of the model calculation parameters were further analyzed to determine the permeability evolution mechanism under the influence of vibration and chemical erosion,to prove the correctness of the mechanism according to the experimental results,and to develop a new method for determining the optimum permeability in uranium *** uranium leaching was found to primarily follow a process consisting of(1)a permeability control stage,(2)achieving the optimum permeability,(3)a chemical reactive rate control stage,and(4)a channel flow *** resolution of these problems is of great significance for facilitating the application and promotion of lowfrequency vibration in the CO_(2)+O_(2) leaching process.

关键词： Low-frequency vibration Low-permeability sandstone uranium migration Permeability evolution mechanism Chemical reactive rate Optimum permeability

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：