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Title: Distribution of uranium and fluoride in some two-phase solvent systems
Author: Waite, Brian Dale Anthony
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1964
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Studies have been made of the extraction from aqueous solution of nitric and hydrofluoric acids, alone and in the presence of each other and, where relevant of hydrochloric acid, into di-(2-ethyl hexyl)phosphate, tri-n-butyl phosphate and tri-n-octylamine. Also, similar studies have been made of the extraction of uranium in the presence of hydrofluoric and nitric acids into the same acidic, neutral and basic organic solvents. In all cases, the practical work has taken the form of equilibrium experiments made under carefully controlled conditions and analysis of the resulting aqueous and organic phases. The organic solvents have been used either alone or as solutions in various inert diluents such as kerosene, benzene or xylene and the aqueous solutions have covered a very wide range of concentrations. From the results of these experiments, deductions have been made regarding the mechanisms of the extraction processes and the nature of the species taken up into the organic media. Equilibrium constants are given and, where sufficient data is available, stability constants have been calculated. The extraction of the mineral acids into di-(2-ethyl hexyl)phosphate and tributyl phosphate is found to be similar. With dilute aquwous solutions, one mole of acid is taken up per mole of extractant and the acid is probably hydrogen bonded to the phosphoryl oxygen. At higher aqueous concentrations, more acid is extracted and possible explanations of this are offered. With tri-octylamine, the acids are extracted as the amine salts R3NH. NO3 or R3NH. HF2 but again more acid than expected is taken up from concentrated aqueous solutions. Uranium is extracted into tributyl phosphate in the presence of nitric or hydrochloric acids but not at all in the presence of hydrofluoric acid and possible explanations are offered for this. With di-(2-ethyl hexyl)phosphate and tri-n-octylamine uranium is extracted in the presence of all acids and it would appear from the results that this is a simple ion exchange process, UO2 2+ exchanging with H+ in the former case and UO2F3 - exchanging with the anion in the latter case.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available