The solid oxide membrane (SOM) process is a direct electrolysis method for refining magnesium and has become a popular and promising technology. In the electrolysis process of SOM, the metal oxide is dissociated into the metal cation and oxygen anion. Thus, it is important to investigate the dissolution reaction of metal oxides in molten fluoride flux, which contributes to the overall reaction mechanism and reaction rate. However, there are few fundamental studies on the reaction between oxide particles and fluoride flux. Notably, the dissolution behavior of magnesium oxide (MgO), which is a major source of magnesium production, into fluoride flux has not been reported. In addition, the dissolution behavior is mediated by the chemical and physical properties of the flux. Therefore, we investigated the dissolution reaction of MgO in fluoride flux using high temperature confocal scanning laser microscopy (HT-CSLM) measurements to demonstrate the reaction mechanism governing the dissolution rate of MgO particles. Consequently, the rate-limiting mechanism is a diffusion of O2− ion, dissociated from MgO, through the boundary layer.
Bibliographical noteFunding Information:
This research was partly supported by the K orea Institute of Energy Technology Evaluation and Planning (KETEP) with grant number 20182020105950 and partly by the Korea Evaluation Institute of Industrial Technology with grant number 10063056 , funded by the Ministry of Trade, Industry and Energy of the Republic of Korea .
© 2019 Elsevier Ltd and Techna Group S.r.l.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Materials Chemistry