1987 Volume 20 Issue 1 Pages 46-51
The extraction of cobalt was studied, using solvating effect diluents such as chloroform and 2-ethylhexyl alcohol, and was compared with results obtained previously for benzene diluent. The solvating effect diluent causes a decrease in the requirement for water and acid as stabilizing molecules for the extractant, and thus prevent water and acid from taking part in the mechanism of cobalt extraction. Aggregation of the extracted cobalt species is also interfered with in the diluent. These effects simplify the mechanism of cobalt extraction. The principal effect is, however, to reduce the extraction performance of the extractant due to stabilization with the diluent. Actually, the extractant is stabilized by forming a bisolvate with alcohol molecules. The extraction equilibrium formulation was established for each diluent, covering a wide range of conditions. The extracted species were monomeric 2:1 complex, (R3R''NCL)2·COCL2, for chloroform diluent, and monomeric 2:1 and 1:1 complexes, (R3R''NCL)2·COCL2 and R3R''NCL·COCL2, for alcohol diluent.
