Unit mass transfer operations gather lots of different techniques to separate compounds. These, are based on the exploiment of different physical and chemical properties of the compounds involved. One of these operations is liquid-liquid extraction, related with solubilities and densities, making it a cheap and easy way to separate different species. Nowadays, liquid-liquid extraction goes a step further with the usage of selective organic extractants which permit more specific extractions. Its power bases on the engagement of certain reactions. Within the huge variety of organic extractants are found certain types of amines and acids. Mixed, they conform precise organic solutions that, applied correctly, will retain the target specie. The present project aims to study how good a mixture of versatic acid 10 + PRIMENE 81-R (primary amine) is, in order to separate aqueous nickel and cobalt in different conditions. The organic phase is meant to be neutral and thus, cations are reatined without releasing protons to the medium. To test the extractant effectiveness, various essays are made modifying several process extraction variables. These changes affect the organic phase concentration, the concentration of salt in the aqueous phase and the initial concentration of metals. From the results, some models may be constructed and hence, the behaviour may be predicted in these particular conditions. Eventually, the simulation of a countercurrent process is designed from empiric data giving a view of how would these studies work in a situation commonly found in industry.