Experimental and modeling investigation of cobalt ion extraction in multistage extractor: Efficient evaluation of mass transfer coefficients using forward mixing approach

摘要

The current study develops comprehensive mass transfer models such as the plug flow model (PFM), backflow model (BFM), axial dispersion model (ADM), and forward mixing model (FMM). A new model of mass transfer was developed based on the size distribution of the dispersed phase droplets, and numerically solved using the technique of fitting concentration profiles. The studied process is a pilot-scale multistage extractor designed to provide proper contact between organic and aqueous phases for the recovery of Co(Ⅱ) ions from dilute solutions. The great agreement of FMM was achieved with an average deviation (AD) of about 10.99%, and 10.50% for X and Y, respectively. The models were further used to evaluate process parameters and physical properties on the backflow, and axial dispersion coefficients. The analysis on the E_C of continuous phase indicates that the proportion of the axial dispersion coefficients transfer increased rapidly from 0.62 to 1.52 cm~2/s as rotation speed increased from 160 to 220 rpm. The agitation rate has a positive influence on the mass transfer, while the effects of inlet flow rates are less than rotation speed. The FMM model has shown to be robust and reliable in the design of the multistage extractor.