With the increased requests for more sustainable extraction processes feedstocks with low metal content are becoming more attractive. In this research, an additional refining step is investigated in order to recover valuable metals from slag generated during nickel extraction process, particularly copper, nickel, and cobalt. Slag was settled at the different temperatures for various times in conditions that simulated the industrial environment. The chemical composition and morphology of newly formed matte and slag were determined. Kinetic parameters of matte formation, valuable metal recovery rates and partition coefficients were deduced. Metals separation and settling rate was found to be strongly dependent on temperature. The highest recovery rates were found to occur at 1598 K (1325 degrees C) for two hour settling while the most economical combination of parameters was found when settling at 1573 K (1300 degrees C) for one hour. Silica additions generated higher partition coefficients for copper and nickel than the addition of lime. It is concluded that an additional refining step involving SiO2 and CaO fluxes is an economical way to recover more than 60% of valuable metals from slag that is disposed in landfills.