The solid oxide membrane (SOM) process is an emerging technology for the environmentally friendly extraction of high-energy-content metals such as magnesium, tantalum, and titanium directly from their respective oxides. This paper reports on the recent success of the SOM process for magnesium production from magnesium oxide dissolved in fluoride-based fluxes in the temperature range 1150°C to 1300 °C. This process employs an inert oxygen-ion-conducting stabilized zirconia membrane to separate the inert cathode in the flux from the anode. When the applied electrical potential between the electrodes exceeds the dissociation potential of magnesium oxide, oxygen ions are pumped out of the melt and through the zirconia membrane to the anode where they are oxidized. Reduced magnesium evolves at the cathode as a vapor and is condensed in a separate chamber yielding a highpurity product. The SOM cell has been electrochemically characterized, and key concepts related to MgO dissociation, leakage current, and mass transfer relevant to the SOM process are explained.

The Solid‐Oxide‐Oxygen‐Ion conducting membrane (SOM) technology offers great potential for environment friendly and energy‐efficient extraction of high‐energy‐content metals. This work was performed to demonstrate the technical viability of the SOM technology to produce tantalum metal and tantalum–niobium alloy directly from tantalum oxide and ore concentrates. An electric potential is applied to dissociate the tantalum oxide source, reduce the Ta metal at the cathode, pump the oxygen ions through the membrane (SOM), and oxidize them at the anode. The process can be used to efficiently produce tantalum metal without the expensive pre‐processing of raw materials and generation of harmful byproducts. The work reported in this paper demonstrates that the SOM process can produce high‐purity tantalum metal. The electrochemical behavior of the cell and the method to increase membrane stability are also discussed.

not Available.

Magnesium hydride particles are suspended in an oil-based medium with dispersants to create a slurry that has great potential for hydrogen production and storage. Hydrogen is generated whenever needed by mixing the magnesium hydride slurry with water in a mixer. The byproduct is benign magnesium hydroxide (milk of magnesia). The primary purpose of the slurry is to moderate the reaction, allow thermal management and make it pumpable so it can be transported and metered like liquids so that the existing transportation infrastructure can be used. Thus, the magnesium hydride slurry lends itself well for automotive applications in conjunction with fuel cells. For such large-volume automotive applications, the success and economic viability of employing magnesium hydride slurry to transport and store hydrogen will depend on developing an effective recycling system for the magnesium hydroxide by-products. This paper discusses the feasibility of employing the Solid-Oxide-Oxygen-Ion-Conducting-Membrane (SOM) process for converting the by-product magnesium hydroxide to magnesium and regenerating the magnesium hydride slurry. The SOM process, in principle, utilizes a tubular yttria-stabilized-zirconia-based solid-oxide-fuel-cell as an anode in the temperature range 1100 – 1300 °C. The magnesium hydroxide is dissolved in a molten ionic flux and with the application of an electrical potential between an inert cathode in the flux and the anode, the oxygen ions are pumped out of the flux through the zirconia membrane and are oxidized at the anode. Magnesium vapor evolves at the cathode and is condensed in a separate chamber (condenser). By performing in-situ reforming of gaseous hydrocarbons within the tubular zirconia anode one can minimize the electrical power required for the electrolysis and generate the required hydrogen needed to convert the magnesium vapors in the condenser back to magnesium hydride.