The influences of the concentration of cosurfactant and surfactant on the water content of the microemulsion were studied, and the proper microemulsion extraction system has been obtained. Secondly, the effects of the concentration of CTMAB, pentanol, ammonium thiocyanate, sodium thiocyanate; and also the volume ratio of aqueous to microemulsion (R) and temperature on the extraction yield (E%) were investigated, the mechanism of the cobalt extraction was discussed. The extraction yield (E%) of nickel was much lower than cobalt, which make the separation of cobalt and nickel possible. In the stripping stage, the metals extracted in the microemulsion phase were precipitated by Na2CO3 solution and the microemulsions were recycled for further use. (c) 2007 Elsevier B.V. All rights reserved.