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Zeng, S., Shen, Y., Sun, B., Zhang, N., Zhang, S., & Feng, S. (2021). Pore structure evolution characteristics of sandstone uranium ore during acid leaching. Nuclear Engineering and Technology, 53(12), 4033–4041.
Abstract: To better understand the permeability of uranium sandstone, improve the leaching rate of uranium, and explore the change law of pore structure characteristics and blocking mechanism during leaching, we systematically analyzed the microstructure of acid-leaching uranium sandstone. We investigated the variable rules of pore structure characteristics based on nuclear magnetic resonance (NMR). The results showed the following: (1) The uranium concentration change followed the exponential law during uranium deposits acid leaching. After 24 h, the uranium leaching rate reached 50%. The uranium leaching slowed gradually over the next 4 days. (2) Combined with the regularity of porosity variation, Stages I and II included chemical plugging controlled by surface reaction. Stage I was the major completion phase of uranium displacement with saturation precipitation of calcium sulfate. Stage II mainly precipitated iron (III) oxide-hydroxide and aluminum hydroxide. Stage III involved physical clogging controlled by diffusion. (3) In the three stages of leaching, the permeability of the leaching solution changed with the pore structure, which first decreased, then increased, and then decreased.
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Zeng, S., Shen, Y., Sun, B., Tan, K., Zhang, S., & Ye, W. (2022). Fractal kinetic characteristics of uranium leaching from low permeability uranium-bearing sandstone. Nuclear Engineering and Technology, 54(4), 1175–1184.
Abstract: The pore structure of uranium-bearing sandstone is one of the critical factors that affect the uranium leaching performance. In this article, uranium-bearing sandstone from the Yili Basin, Xinjiang, China, was taken as the research object. The fractal characteristics of the pore structure of the uranium-bearing sandstone were studied using mercury intrusion experiments and fractal theory, and the fractal dimension of the uranium-bearing sandstone was calculated. In addition, the effect of the fractal characteristics of the pore structure of the uranium-bearing sandstone on the uranium leaching kinetics was studied. Then, the kinetics was analyzed using a shrinking nuclear model, and it was determined that the rate of uranium leaching is mainly controlled by the diffusion reaction, and the dissolution rate constant (K) is linearly related to the pore specific surface fractal dimension (DS) and the pore volume fractal dimension (DV). Eventually, fractal kinetic models for predicting the in-situ leaching kinetics were established using the unreacted shrinking core model, and the linear relationship between the fractal dimension of the sample’s pore structure and the dissolution rate during the leaching was fitted.
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Zagana, E., Obeidat, M., Külls, C., & Udluft, P. (2007). Chloride, hydrochemical and isotope methods of groundwater recharge estimation in eastern Mediterranean areas: a case study in Jordan. Hydrological Processes: An International Journal, 21(16), 2112–2123.
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Zagana, E., Külls, C., Udluft, P., & Constantinou, C. (2007). Methods of groundwater recharge estimation in eastern Mediterranean water balance model application in Greece, Cyprus and Jordan. Hydrological Processes: An International Journal, 21(18), 2405–2414.
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Zagana, E., Külls, C., & Udluft, P. (2000). Der Wasserhaushalt des Aliakmonas. Vom Wasser, 94, 29–39.
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