Cobalt(II) membrane-extraction by DP-8R/Exxsol D100 using pseudo-emulsion based hollow fiber strip dispersion (PEHFSD) processing

Abstract

The transport of cobalt(II) from acidic sulphate solutions through PEHFSD was investigated using the extractant DP-8R in Exxsol D100. The acidic feed solution containing Co(II) was passed through the tube side, and pseudo-emulsions of DP-8R/Exxsol D100 and sulphuric acid was passed through the shell side in counter-current mode, using a single microporous hydrophobic polypropylene hollow fiber contactor for extraction and stripping. In PEHFSD the aqueous strip (sulphuric acid) solution was dispersed in the organic membrane solution in a reservoir tank with an impeller stirrer to form a strip dispersion. This pseudo-emulsion phase is circulated from the tank to the membrane module to provide a constant supply of the carrier solution to the membrane micropores. Several hydrodynamic and chemical parameters, such as variation in feed pH (3-7), cobalt concentration in feed (0.17-1.7x10 -3 M), carrier concentration (0.16-1.28 M), etc., were investigated. Mass transfer modelling was performed and the validity of the model was evaluated with experimental data. Moreover, the system was 2 applied in the cobalt purification of synthetic lithium solutions derived from the processing of rechargeable batteries, with cobalt/lithium separation factor values around 25.

Yttrium (III) Recovery with D2EHPA in Pseudo-Emulsion Hollow Fiber Strip Dispersion System

“…Also, the driving force of differential concentration is decreased as the volumetric ratio increases. This effect was also reported in previous studies on the permeation of Cu(II) 16 , Co(II) 31 and Au(I) 34 via PEHFSD system.

Figure 3 The effects of volumetric ratio of feed to strip dispersion on concentration ratio of Y(III) in the feed and strip phase versus time, Y(III) concentration in feed phase = 1 mM feed agents = 0.5 M HNO 3 , stripping agents = 3.0 M HNO 3 , D2EHPA concentration in kerosene = 0.1 M, the flow rate of feed: stripping dispersion solution = 300:200 mL/min, stirring speed = 500 rpm and operating time = 30 min in circulating mode.

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“…Also, PEHFSD system has been applied for the recovery of various metal ions i.e. Cu(II) 16 , 17 , Zn(II) 18 , 19 , Au(I) 20 , Co(II) 21 , Cr(III) 22 , 23 , Cr(VI) 24 from aqueous solutions. However, to the best of our knowledge, the implementation of PEHFSD system to recover Y(III) from aqueous solution has not been previously reported.…”