1984 Volume 17 Issue 4 Pages 417-423
A practical study was carried out to determine the optimal operating conditions for the separation of cobalt from nickel. With non-polar solvents as diluents, no problem associated with the viscosity of the organic phase and the interfacial tension arises so long as the loading ratio of the organic phase is maintained less than 0.8. A cobalt solution containing a nickel contamination of less than 0.005% was obtained, using single-stage extraction followed by single scrubbing. The addition of 10 % 2-ethylhexyl alcohol results in serious lowering of the separation factor, although it has the advantage of preventing third-phase formation during the conversion of the extractant to its sodium salt. The alkali metal hydroxide equivalent to the amount of metal to be extracted is required in the extraction. As a prospective process, a continuous extraction was carried out satisfactorily in which sodium hydroxide solution was fed into the stage together with the acid form of the extractant diluted in xylene and the aqueous feed stream.
