Performance evaluation of a cylindrical air-lift mixer-settler device and optimization of process parameters for the extraction of uranium (VI) from nitric acid medium

A customized single-stage cylindrical combined air lift mixer-settler (C-CALMIX) device has been developed and its performance was evaluated by studying the extraction behavior of U(VI) in a solution of 1.1 M tri-n-butyl phosphate (TBP) in n–dodecane (n-DD) from 4 M nitric acid medium, at 298 K. The extraction of U(VI) was studied as a function of process parameters of the C-CALMIX such as flow-rate of organic and aqueous phases, ratio of organic to aqueous flow-rates, air flow-rate etc., that are amenable for variation. The distribution ratio of U(VI) obtained under dynamic conditions in a C-CALMIX was compared with those obtained in a batch equilibrium mode. The process parameters were optimized to obtain high distribution ratio of U(VI) in C-CALMIX, comparable to that obtained at batch equilibrium mode without compromising the throughput of C-CALMIX. The stripping behavior of U(VI) from the loaded organic phase was studied using 0.01 M nitric acid. The results are reported in this paper.