AbstractThis paper is a contribution to the theoretical and quantitative understanding of the processes for the production of magnesium metal by metallothermic process in vacuum (Pidgeon Process). In the present study, effects of reductant type and amount were investigated. CaC₂ is a low-cost alternative to FeSi (ferrosilicon) which is the common reductant in the Pidgeon Process. CaC₂ slightly decreases the Mg recovery ratios but it remarkably decreases the process cost. The experimental study, conducted with the change of mass % FeSi–CaC₂ ratio at 1,250 °C for 360 min, the optimum Mg recovery was measured as 94.7 % at 20 % CaC₂ addition. Also aluminum, as a reductant, allows conducting the process at lower temperatures than that of FeSi. For the experiments conducted with Al addition, the highest Mg recovery ratio was measured as 88.0 % in the conditions for 300 min process duration and 100 % stoichiometric Al addition at 1,200 °C.