Aluminothermic Reduction of Sulfides via Reactive Vacuum Distillation

Abstract

Master alloys for aluminum serve as a source of alloying elements that are essential to tailoring the metal to its many end uses, ranging from automotive to aerospace to structural applications. Presently, aluminum master alloy production is complicated by challenges ranging from high emissions and costs to low yields and productivities. While master alloys are typically produced from oxide, halide, or metallic feedstocks, sulfide chemistry provides a new opportunity to reduce economic and environmental costs via process intensification and increased yields. Herein, we explore the production of aluminum master alloys from sulfide feedstocks through aluminothermic reduction via reactive vacuum distillation. We present a thermodynamic framework to elucidate the behavior of aluminum as a reductant for sulfides, focusing on volatility and gas atmosphere. We demonstrate the production of a 10 wt% manganese master alloy via aluminothermic reduction of manganese sulfide, with a manganese yield of over 95%. Our thermodynamic and experimental results suggest that aluminothermic reduction of sulfides is a possible new route for the production of aluminum master alloys.