Master alloys containing elements ranging from manganese to silicon to rare earths such as scandium are critical feedstocks for aluminum alloy production, yet their manufacture is often complicated by factors ranging from low yields in the alloying process to challenges with upstream reduction of the alloying element. Meanwhile, recent innovations in metal oxide sulfidation chemistry supports deploying new metal sulfide feedstocks for use in emerging, sustainable, metal reduction technologies. Herein, we present a novel metal sulfide aluminothermic reduction process for aluminum master alloy production via reactive vacuum distillation. We demonstrate its principles and efficiency for aluminum-manganese, aluminum-silicon, aluminum-zirconium, and aluminum-rare earth master alloy production. Supported by an integrated thermodynamic, kinetic, and mass-transport framework, we define a path to predict master alloy product yield, and explore the propagation of impurities such as sodium, iron, oxygen, sulfur, and halides through the process.