Solvent extraction kinetics of Sm (Ⅲ)

Eu (Ⅲ) and Gd (Ⅲ) from hydrochloric acid have been focused on using 2-ethylhexyl phosphoric acid-2-ethylhexyl ester (P507) with Anordning for Kontinuerlig Undersokning av Fordelningsfaktore vid Vatske Extraction (AKUFVE). Compared with the conventional set-up

some advantages emerge obviously

for example

fast phase separation

easy operation and convenience of kinetic data acquisition. First of all

the extraction mechanism was discussed based on the dimeric model of P507. Secondly

the effects of stirring speed were investigated and 420 r·min

-1

was determined of the following experiments. The effects of pH

concentration of rare earth elements (REEs) and P507 on the extraction rate were analyzed. The results indicated that the extraction mechanism changed with the increasing concentration of P507. Then

the experiments with different temperature were carried out. It turned out that the values of apparent activation energy (E

a

) for Sm(Ⅲ)

Eu(Ⅲ) and Gd(Ⅲ) extracted by P507 were 26.80 kJ·mol

-1

13.40 kJ·mol

-1

and 11.10 kJ·mol

-1

respectively

the resistance of the entire

process was limited by diffusion or both of diffusion and reaction. Finally

the correlation equations were obtained

and the theoretical results fit with the experimental data well

most relative error was within ±30%.