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

2013 ◽  
Vol 49 (2) ◽  
pp. 183-190 ◽  
Author(s):  
J. Milshtein ◽  
E. Gratz ◽  
S. Pati ◽  
A.C. Powell ◽  
U. Pal
Keyword(s):  
Magnesium Oxide ◽  
Numerical Approach ◽  
Electrolytic Cell ◽  
Membrane Stability ◽  
Yttria Stabilized Zirconia ◽  
Low Carbon ◽  
Stabilized Zirconia ◽  
Operating Life ◽  
Magnesium Production ◽  
Ion Conducting

The Solid Oxide Membrane (SOM) process for magnesium production 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 oxy-fluoride flux. 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, and one way the YSZ degrades is by yttria diffusion out of the YSZ. By adding small amounts of YF3 to the flux, yttria diffusion can be 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-YSZ interface. Yttria concentrations were determined using x-ray spectroscopy. The diffusion process was modeled using a numerical approach with an analytic solution to Fick?s second law. These modeling and experimental methods allowed for the determination of the optimum YF3 concentration in the flux to minimize yttria diffusion and improve membrane stability. Furthermore, the effects of common impurities in magnesium ores, such as calcium oxide, silica, and sodium oxide/sodium peroxide, on YSZ stability are being investigated.

Direct Electrolytic Reduction of Solid Cr2O3 to Cr Using SOM Process

2013 ◽  
Vol 690-693 ◽  
pp. 78-81
Author(s):  
Chao Yi Chen ◽  
Zhi Hui Mao ◽  
Jun Qi Li
Keyword(s):  
Liquid Copper ◽  
Cell Voltage ◽  
Graphite Powder ◽  
Solid Oxide ◽  
Yttria Stabilized Zirconia ◽  
Particle Sizes ◽  
Electrolysis Time ◽  
Stabilized Zirconia ◽  
Oxygen Ion ◽  
Ion Conducting

A novel process of solid-oxide-oxygen-ion conducting membrane (SOM) technique has been investigated to produce Cr metal directly from Cr2O3 in molten CaCl2. The sintered porous Cr2O3 pellet was employed as the cathode while liquid copper, saturated with graphite powder and encased in a one-end-closed yttria-stabilized-zirconia (YSZ) tube, acted as the anode. The particle sizes and porosity of the cathode pellets are important factors that have significant impact on the electrolysis process. The optimal experimental condition is pellet forming pressure 4MPa, sintering and electrolytic temperature 1150°C, cell voltage 3.5V, electrolysis time 2h.

Study of Mechanical Properties of Magnesium Oxide Doped Alumina (Al2O3) and Yttria Stabilized Zirconia (YSZ) Composite for Medical Applications

2012 ◽  
Vol 506 ◽  
pp. 521-524 ◽  
Author(s):  
A. Phothawan ◽  
K. Nganvongpanit ◽  
T. Tunkasiri ◽  
Sukum Eitssayeam
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Magnesium Oxide ◽  
Sintering Temperature ◽  
The Body ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Electron Microscopes ◽  
Pin On Disk ◽  
Scanning Electron Microscopes

The aim of this research is to study the mechanical properties such as hardness ,wear resistance etc , of the magnesium oxide (MgO) doped alumina (Al2O3) and yttria stabilized zirconia (YSZ) composite, We first prepared MgO-doped Al2O3(denoted as Al4) by mixing Al2O3powder and 0.4 wt% of MgO powder. After that Al4powder was mixed YSZ powder, with the formula [(x)Al4- (100-x)YS when x was varied from 0 - 100 by wt%. The samples were sintered at 1450, 1500, 1550, 1600 and 1650 °C. In addition, microstructure of the surface was studied employing both optical and scanning electron microscopes. The hardness of the surface was investigated by Vickers indentation technique and pin on disk apparatus was employed for wear rate measurement. The results showed that the density and volume shrinkage decreased with the increase of Al4content. The grain size and porosity of the specimens tend to decrease when the sintering temperature increases. The hardness and wear resistance of the samples increased with the increase of Al4up to 90 %. It was also found that the material is not toxic to the body.

Yttria-stabilized zirconia thin films with restrained columnar grains for oxygen ion conducting electrolytes

2016 ◽  
Vol 42 (15) ◽  
pp. 16703-16709 ◽  
Author(s):  
Soonwook Hong ◽  
Dohaeng Lee ◽  
Yonghyun Lim ◽  
Jiwoong Bae ◽  
Young-Beom Kim
Keyword(s):  
Thin Films ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Oxygen Ion ◽  
Columnar Grains ◽  
Ion Conducting

Direct Extraction of Ti and Ti Alloy from Ti-Bearing Dust Slag in Molten CaCl2

2016 ◽  
Vol 35 (6) ◽  
pp. 591-597
Author(s):  
Chaoyi Chen ◽  
Chong Zhao ◽  
Junqi Li ◽  
Shufeng Yang
Keyword(s):  
Liquid Copper ◽  
Pure Titanium ◽  
Graphite Powder ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Direct Extraction ◽  
Oxygen Ion ◽  
Porous Cathode ◽  
Ion Conducting ◽  
Impurity Elements

AbstractUsing process of solid oxygen-ion conducting membrane (SOM), titanium metal and its alloy can be prepared directly from Ti-bearing dust slag by immersing it in the molten CaCl2 at 1,100℃, which has been proposed by constant voltage of 3.5 V for 2–6 h. The dust slag was ball-milled and pressed into pellets, then employed as the cathode, while the liquid copper, which was saturated with graphite powder and encased in yttria-stabilized zirconia (YSZ) tube, acted as the anode. The effect of forming pressure and electrolytic time on products was analyzed. The results show that the content of titanium increased with electrolytic time and the characteristic morphology presents as granule. Ti–Fe alloy can be obtained from Ti–Fe residue by 6 h electrolysis. For titanium-rich residue, when the forming pressure of pellets decreased from 6 to 3 MPa, only electrolysis for more than 4 h can completely remove the oxygen, and pure titanium is obtained by 6 h electrolysis. Besides, there is an unprecedented finding that the porous cathode is conducive to the removal of impurity elements.

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