High Temperature Electrochemistry III: Materials Electrochemistry I
Sponsored by: TMS Extraction and Processing Division, TMS: Pyrometallurgy Committee, TMS: Hydrometallurgy and Electrometallurgy Committee
Program Organizers: Prabhat Tripathy, Idaho National Laboratory; Guy Fredrickson, Idaho National Lab; Boyd Davis, Kingston Process Metallurgy Inc

Wednesday 2:00 PM
March 1, 2017
Room: 16A
Location: San Diego Convention Ctr

Session Chair: Uday Pal, Boston University; Steven Herrmann, Idaho National Laboratory

2:00 PM  
Molten Flux Design for Solid Oxide Membrane Based Electrolysis of Si from Silica: Thomas Villalon1; Uday Pal1; Soumendra Basu1; 1Boston University
    A one-end-closed oxygen-ion-conducting stabilized zirconia (SOM) tube is used to separate pure silica (SiO2) dissolved in an appropriately engineered molten flux from an inert anode placed inside the SOM tube. To ensure product purity, a pre-reduction step using a secondary cathode at lower applied potentials is employed to remove impurities that are more electronegative than Si. The impurity-laden secondary cathode is removed, and then employing a liquid tin cathode in the molten flux the applied potential is increased to reduce the dissolved silica. The reduced Si go into solution in the liquid tin cathode. Less electronegative impurity ions compared to Si remain in the flux. Thus impurity oxides of both more and less electronegative impurities are not reduced along with silica.