Yttria stabilized zirconia membrane stability in molten fluoride fluxes for low-carbon magnesium production by the SOM process
The Solid Oxide Membrane (SOM) process for magnesium production is a technology that involves the direct electrolysis of magnesium oxide for energy efficient and low-carbon magnesium production. In the SOM process, magnesium oxide is dissolved in a molten ionic flux comprised of a CaF2 - MgF2 eutectic mixture. An oxygen-ion-conducting SOM tube, made from yttria stabilized zirconia (YSZ), is submerged in the flux. The operating life of the electrolytic cell can be improved by understanding degradation processes in the YSZ membrane, and one way in which the membrane degrades is by yttria diffusion out of the membrane. By adding small amounts of yttrium fluoride to the flux, yttria diffusion can be limited and controlled. The diffusion of yttria into the flux was quantified by determining the yttria concentration profile as a function of immersion time in the flux and distance from the flux-membrane interface. Yttria concentrations were determined using energy dispersive spectroscopy (EDS) and wavelength dispersive spectroscopy (WDS). The diffusion process was modeled using a numerical approach in conjunction with an analytic solution to Ficks second law. These modeling and experimental methods allowed for the determination of the optimum yttrium fluoride concentration in the flux to minimize yttria diffusion and improve membrane stability. Furthermore, the effects of certain impurities commonly found in magnesium ores, such as calcium oxide, silica, and sodium oxide/sodium peroxide, on membrane stability are also being investigated under static and potentiodynamic conditions.
Magnesium Solid oxide membrane SOM YSZ Diffusion
Jarrod MILSHTEIN Eric GRATZ Soobhankar PATI Adam C. POWELL Uday PAL
Division of Materials Science and Engineering, Boston University, 15 Saint Marys St., Brookline, MA Division of Materials Science and Engineering, Boston University, 15 Saint Marys St., Brookline, MA Metal Oxygen Separation Technologies, Inc., 11 Michigan Drive, Natick, MA 01760, USA
国际会议
Ninth International Conference on Molten Slags,Fluxes and Salts(第九届国际熔渣、溶剂与熔盐学术会议 MOLTEN12)
北京
英文
1-13
2012-05-27（万方平台首次上网日期，不代表论文的发表时间）