Emerging SOM technology for the green synthesis of metals from oxides

This article is intended to demonstrate that the environmentally sound solid-oxide-membrane (SOM) technology is an emerging process that can efficiently synthesize metals and alloys directly from their oxide ores with minimum feed-material preparation and produce oxygen gas or water vapor as the major byproduct. To demonstrate the proof-of-concept and economic viability, this article will focus on the synthesis of magnesium metal. The current production methods for magnesium are either metallothermic reduction (magnetherm process) at thig temperatures (1,600°C) involving expensive metal reductant (FeSi) or electrolysis from a halide electrolyte bath that requires extensive and expensive feed-material preparation. Both these techniques are also energy intensive, have low yield and generate large quantities of waste reaction products harmful to the environment. In the SOM process, the oxide reduction is electrochemical and has efficiencies close to 100%. It will be shown that unlike the current metallothermic and the electrolytic processes, the SOM process has the potential to be more economic and less energy intensive, and its process products are environmentally benign. The results reported in this article for magnesium synthesis are also applicable for environmentally sound production of other high-energy-content metals that are produced by less-efficient techniques that result in environmentally harmful reaction products. To date, in addition to magnesium, the SOM process has been used to produce silicon, chromium, and iron, along with alloys from their respective oxides dissolved in appropriate solvents.