Separation of Cobalt and Nickel from Concentrated HCl Solutions by Winsor II Microemulsion System with N235 as Carrier

Abstract

The selective extraction of cobalt from concentrated HCl solutions by Winsor II microemulsion system using tertiary amine N235 as carrier was studied. In the hexadecyl trimethyl ammonium chloride (HDTAC)/n-pentanol/n-heptane/HCl/N235 system, HDTAC was used as a cationic surfactant to form microemulsion in n-heptane, n-pentanol was injected in the microemulsion as a cosurfactant and N235 was a typical extractant in the system. The microemulsion system without N235 showed poor extractability and stability. However, by adding N235, the extraction yield (E %) of cobalt can be almost 92 %, that of nickel was always very low. The influence of different parameters such as surfactant concentration, extractant concentration, hydrochloric acid concentration of the feed solutions, cosurfactant concentration as well as temperature on the extraction yield (E %) were investigated. The results showed 92 % of cobalt was extraced by microemulsion, while the extraction yield of nickel was very low which made the separation of cobalt and nickle possible.