Title: Interphase transfer kinetics of uranium between phosphoric acid and DEPA-TOPO extractant using Lewis cell techniques
Abstract: Rate constants for the interphase transfer of uranium from pure and plant solutions of phosphoric acid by DEPA-TOPO solvent have been measured in a Lewis cell. In pure H3PO4, the forward (aqueous to organic) rate constant, k′, decreased from 0.038 cm/min in 4 M H3PO4 to 0.006 cm/min in 8 M H3PO4, a factor of about six. Arrhenius plots of log k′ vs. 1T showed an activation energy of only 3.7 kcal/mol (15.5 kJ/mol), as compared to a value of 12.2 kcal/mol (51.0 kJ/mol) for the reverse reaction. The addition of typical impurities, such as humic matter and defoaming agents, to pure solutions of H3PO4 resulted in a significant decrease in k′. Rate constants for plant acid that had been cleaned of most of the humid matter by treatment with activated carbon were about 4 times higher than untreated acid. Residence times for mixing have been calculated for the various conditions.
Publication Year: 1986
Publication Date: 1986-06-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 13
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