Yttria stabilized zirconia membrane stability in molten fluoride fluxes for low-carbon magnesium production by the SOM process

Journal of Mining and Metallurgy. Section B: Metallurgy

关键词: Magnesium;    Solid oxide membrane;    SOM;    YSZ;    Diffusion;   

DOI  :  10.2298/JMMB120809005M

来源: DOAJ

【 摘 要 】

The Solid Oxide Membrane (SOM) process for magnesium production involves thedirect electrolysis of magnesium oxide for energy efficient and low-carbonmagnesium production. In the SOM process, magnesium oxide is dissolved in amolten oxy-fluoride flux. An oxygen-ion-conducting SOM tube, made from yttriastabilized zirconia (YSZ), is submerged in the flux. The operating life ofthe electrolytic cell can be improved by understanding degradation processesin the YSZ, and one way the YSZ degrades is by yttria diffusion out of theYSZ. By adding small amounts of YF3 to the flux, yttria diffusion can becontrolled. The diffusion of yttria into the flux was quantified bydetermining the yttria concentration profile as a function of immersion timein the flux and distance from the flux-YSZ interface. Yttria concentrationswere determined using x-ray spectroscopy. The diffusion process was modeledusing a numerical approach with an analytic solution to Fick’s second law.These modeling and experimental methods allowed for the determination of theoptimum YF3 concentration in the flux to minimize yttria diffusion andimprove membrane stability. Furthermore, the effects of common impurities inmagnesium ores, such as calcium oxide, silica, and sodium oxide/sodiumperoxide, on YSZ stability are being investigated.

【 授权许可】

Unknown