作者机构：
[周新尧; 李咏梅; 谭凯旋; 李春光; 周泉宇] School of Nuclear Resources Engineering, University of South China, Hengyang, China;[刘泽华] School of Urban Construction, University of South China, Hengyang, China
通讯机构：
School of Nuclear Resources Engineering, University of South China, Hengyang, China
通讯机构：
[Tan, Kaixuan] U;Univ South China, Sch Nucl Resources Engn, Hengyang 421001, Peoples R China.
关键词：
Complex surfactant;Leaching kinetics;Resin adsorption and elution;Low permeable sandstone uranium deposit;In-situ leaching of uranium mining
摘要：
Applications of a complex surfactant developed in-house to in-situ leaching of low permeable sandstone uranium deposits are described based on results from agitation leaching, column leaching, resin adsorption, and elution experiments using uranium containing solution from the in-situ leaching site. The results of agitation leaching experiments show that adding surfactant with different concentrations into leaching solution improves the leaching rate of uranium. The maximum leaching rate of uranium from agitation leaching reached 92.6% at an added surfactant concentration of 10 mg/l. Result of column leaching experiment shows that adding surfactant with varying concentrations into leaching solutions increased the permeability coefficient of ore-bearing layer by 42.7-86.8%. The leaching rate of uranium from column leaching increased by 58.0% and reached 85.8%. The result of kinetic analysis shows that for the extraction of uranium controlled by diffusion without surfactant the apparent rate constant 0.0023/d changed to 0.0077/d for the extraction with surfactant controlled by both diffusion and surface chemical reactions. Results from resin adsorption and elution experiments show that there was no influence on resin adsorption and elution of uranium with an addition of 50 mg/l surfactant to production solution from in-situ leaching. The adsorption curve, sorption capacity of resin, recycling of resin remained the same as without adding any surfactant. Introducing complex surfactant to leaching solution increased the peak concentration of uranium in eluents, reduced the residual uranium content in resin, and promoted the elution efficiency. The method of using a complex surfactant for in-situ leaching is useful for low permeable sandstone uranium deposits. (C) 2014 Elsevier B.V. All rights reserved.
关键词：
Leaching of uranium;Sandstone uranium ores;Supercritical CO2 fluid
摘要：
Uranium is an important fuel for nuclear power, so the mining and milling of uranium is the base for development of nuclear power. Our experiments study is about the supercritical CO2 fluid extraction of uranium in low grade uranium ore, and the influence of aqueous medium, oxidants, chelating agents and other factors on the uranium leaching. In aqueous media, Fe2 (SO4)3 as the oxidants, supercritical CO2 fluid extraction of uranium has the best effect, the uranium leaching rate reaches 90.44%, significantly higher than that of the conventional acid and alkaline leaching. In the process of extraction of uranium in supercritical CO2 fluid, the uranium in uranium ore is first oxidized to hexavalent uranium, and then forms high solubility of uranyl carbonate complexes. Supercritical CO2 fluid is expected to be used in in-situ leaching of uranium mining of the low grade sandstone uranium deposits.
摘要：
A uranium mill tailings, located in Guangdong, was selected for spatial distribution of the radon exhalation rates measured by local static method. The two-dimension surface of radon exhalation rates was established by Surfer using the data of spatial distribution of radon exhalation rates measured at August 14, 2007 to 19 and 21, which was analyzed by fractal method of projective covering. The results show that the two-dimension surface of radon exhalation rates is of fractal structure. The fractal dimension of surface of radon exhalation rates from August 14, 2007 to 19 and 21 are 2.0535, 2.0173, 2.0029, 2.0084, 2.0079, 2.0057 and 2.0034, respectively, which indicates that the complexity of spatial distribution of the radon exhalation rates at 14 and 15 are larger than that of the other days. The phenomenon results from the change of precipitation and temperature, as well as the features of uranium mill tailings, including mineral composition, particle size, radium content, porosity and pore connectivity, etc.
摘要：
The effect of a complex surfactant on in situ leaching of low permeable sandstone uranium deposits is discussed, based on an Agitation leaching and a column leaching experiments. The results of the Agitation leaching experiment show that adding different concentrations surfactant into leaching solutions increases significantly the leaching rate of uranium. For a surfactant concentration of 10 mg/l, the leaching rate of uranium reaches maximum 92.6%. The results of the column leaching experiment show that adding 10mg/L surfactant into leaching solutions increases the permeability coefficient of ore-bearing layer 28.8% and the leaching rate of uranium 58.0%, resulting in 85.79%. The results of kinetic analysis show that extraction of uranium is controlled by diffusion with apparent rate constant of 0.0023/d without adding surfactant and by surface chemical reaction with apparent rate constant of 0.0077/d with adding surfactant. Thus, for low permeable sandstone uranium deposit, the in situ leaching mining is of great potential if adding the complex surfactant into leaching solutions.
