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uranium-conversion-facilities
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Fluoride Removal from Radioactive Wastes of Isfahan's UCF Plant by Using Chemical Precipitation Method
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Yavari, Ramin (Supervisor) ; Davarkhah, Reza (Co-Advisor)Fluoride Removal from Radioactive Wastewater of UCF Plant by Adsorption
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Sepehrian, Hamid (Supervisor)
Abstract
In this research, a review on fluoride adsorption revealed that the modification of the adsorber surface with ions like Ca2+ results in great enhancement of the fluoride adsorption. It seems that the enhancement in fluoride adsorption by the modified adsorber, is mainly due to the selective chemical binding of the fluoride ion with the surface-bound ion (Ca2+), regardless of the base material itself. In order to confirm this hypothesis, two different adsorber materials namely, γ-alumina (a material, conventionally used for fluoride removal from water and wastewater) and Micro-silica (a mineral with small adsorption capacity for fluoride) were selected for further study. It was found that the...
Fluride Removal from Wastewater of Isfahan’s UCF Plant by Adsorption, Column Experiment Method
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Sepehrian, Hamid (Supervisor)
Abstract
During production process in Uranium Conversion Facility (UCF) plant at Isfahan, the liquid waste containing uranium compounds, is directed to evaporation lagoons. Gradually, a considerable amount of precipitation will form at the bottom of these lagoons. Uranium concentration in this precipitation is very high and can range from tens of ppm to the order of a few weight percent. As such, it seems that uranium recovery from the UCF waste liquid is not only economically advantageous, but also effective for protecting the environment.The liquid waste resulting from the uranium extraction process contains a great amount of Fluoride ( ppm or higher) which cannot possibly be thrown away into...
Modeling of Dissolution of Sluge from Evaporation Lagoons of Isfahan's UCF Plant
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Charkhi, Amir (Supervisor) ; Otukesh, Mohammad (Co-Advisor)
Abstract
Uranium conversion process is one of the most important stages in nuclear fuel cycle. The Uranium Conversion Facilities (UFC) of Iran is located in Isfahan. In this plant, the Yellowcake (impure uranium oxide, U3O8) is converted to Uranium hexa-fluoride, UF6. During the process, considerable amounts of uranium-containing liquid waste are generated. This liquid waste was collected in evaporation pools inside the UCF Plant. In the course of time, a thick layer of precipitated salt form in bottom of the pools which are collected and stored in drums inside a building. This solid waste contains uranium at concentration levels much higher than that permitted for land disposal of the waste....
Uranium recovery from UCF liquid waste by nanoporous MCM-41: Breakthrough capacity and elution behavior studies
, Article Research on Chemical Intermediates ; Volume 39, Issue 3 , 2013 , Pages 951-959 ; 09226168 (ISSN) ; Tavakoli, H ; Samadfam, M ; Semnani, F ; Asadi, Z ; Sepehrian, H ; Sharif University of Technology
2013
Abstract
Adsorption and recovery of uranium by nanoporous MCM-41 from aqueous solutions (synthetic solution and uranium conversion facility liquid waste) were investigated by use of a fixed-bed column (1.2 cm diameter and 3.0 cm height). Adsorption was carried out at flow rates 0.2 and 0.5 mL min-1, which correspond to retention times of 10 and 6 min. The maximum breakthrough capacity for uranium ions was achieved by use of nanoporous MCM-41 at the optimum pH of 3.6 and flow rate 0.2 mL min-1 (61.95 μg g-1). The Thomas and Yan models were applied to the experimental data, by use of linear regression, to determine the characteristics of the column for process design. The breakthrough curves calculated...
Recovery of uranium from UCF liquid waste by anion exchange resin CG-400: Breakthrough curves, elution behavior and modeling studies
, Article Annals of Nuclear Energy ; Volume 54 , April , 2013 , Pages 149-153 ; 03064549 (ISSN) ; Sepehrian, H ; Semnani, F ; Samadfam, M ; Sharif University of Technology
2013
Abstract
Continuous fixed-bed column studies were carried out by using Amberlite CG-400 anion exchange resin for the recovery of uranium from aqueous solutions (synthetic solutions and uranium conversion facility (UCF) liquid waste). Effects of operating parameters such as flow rate and bed height were studied. The breakthrough capacity decreases with increasing flow rate, but this dependence was not significant with a long column. The maximum breakthrough capacity of uranium ions were achieved by CG-400 resin at a flow rate of 0.2 mL min-1 and bed height 9.1 cm (4 g resin). The elution behavior of uranium from CG-400 resin by various eluents have been investigated and the results show that 0.5 mol...
Studies on the recovery of uranium from nuclear industrial effluent using nanoporous silica adsorbent
, Article International Journal of Environmental Science and Technology ; Volume 9, Issue 4 , October , 2012 , Pages 629-636 ; 17351472 (ISSN) ; Samadfam, M ; Asadi, Z ; Sharif University of Technology
Springer
2012
Abstract
In this paper, the sorption of uranium onto nanoporous silica adsorbent in the presence of nitrate, sulfate, chloride, fluoride and phosphate was studied. The effect of contact time between the nanoporous sorbent and aqueous solution, pH and initial concentration of uranium was also investigated. Uranium sorption onto nanoporous silica adsorbent is a very fast process as sorption rate increases with pH increment. Optimum pH for uranium sorption was 4-8. Experimental sorption isotherm is successfully described by Langmuir and Freundlich models. The results obtained by batch experiments showed that the presence of high concentration of nitrate, sulfate, chloride and phosphate anions alone had...