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Removing Uranium and Radium from Groundwater by Ion Exchange Resins
Published in Arup K. Sengupta, Ion Exchange Technology, 2021
Dennis A. Clifford, Zhihe Zhang
For Reaction (26), there may be some uranyl hydroxide complexes produced as intermediate products that hydrolyze to UO3(s) at very high pH conditions. Adding Reactions (23) and (26) gives the net reaction: () R4UO2(CO3)3+4NaCl+2NaOH=4RCl+UO3(s)+H2O+3CO32−+6Na+
Hydrometallurgy — An Introductory Appraisal
Published in C. K. Gupta, T. K. Mukherjee, Hydrometallurgy in Extraction Processes, 2019
and the cathodic reaction yields OH− ions according to Equation 33. The hydroxyl ions are neutralized by the acid, and the precipitation of uranyl hydroxide is prevented. The alkaline medium for leaching uranium oxide is sodium carbonate solution. The dissolution reaction () UO2+3CO32−+l2O2+H2O→UO2(CO3)34−+2OH−
Removal of Inorganic Contaminants
Published in Samuel D. Faust, Osman M. Aly, Chemistry of Water Treatment, 2018
Softening of hard waters has been reported to reduce the Ra226 content by 80–92% and the U content by 85–99% (Table 9.24).99 Laboratory jar tests were employed for an evaluation of lime softening for U removal from a surface water.108 Lime dosages ranged from 50 to 250 mg/L, which raised the pH values to 10.6 to 11.5 where 85–90% of the U was removed. Experiments were also conducted with MgCO3 and lime at pH values 9.8 to 10.6 where the effectiveness of U removal was reduced. A pH value of 10.6 appears to be critical in these systems. Above this value, lime and MgCO3 combinations increased U removals to 93–99%. In all probability, Mg(OH)2 is precipitated, which removes a uranyl hydroxide complex, (UO2)3(OH)5+, perhaps by adsorption. Additional information is found in Reference 99 on the lime softening removal of several artificially manufactured radionuclides.
Development of practical decontamination process for the removal of uranium from gravel
Published in Environmental Technology, 2018
Ilgook Kim, Gye-Nam Kim, Seung-Soo Kim, Jong-Won Choi
The removal of uranium from the waste solution was accomplished by precipitation in the form of uranyl hydroxide. In order to precipitate uranium from the waste solution, sodium hydroxide (NaOH), aluminum sulfate (Al2(SO4)3), and magnetite (Fe3O4) were used as a precipitant, cohesive agent, and cohesion additive agent, respectively [10]. After precipitation, by filtering the waste solution with Whatman filter paper No. 4, the remaining precipitate residue was filtered out and dried to be treated as a radioactive waste, and then the supernatant was gathered for the application of washing solution. The flow chart of the integrated system for decontaminating uranium-polluted gravel is shown in Figure 2.