Clean Metals Production by Solid Oxide Membrane Electrolysis Process

Xiaofei Guan,Shizhao Su,Uday B Pal,Yihong Jiang

doi:10.1007/s40831-016-0044-x

Xiaofei Guan, Shizhao Su + Show 2 more

Open Access

https://doi.org/10.1007/s40831-016-0044-x

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Abstract

This paper reviews a clean metals, production technology that utilizes an oxygen-ion-conducting solid oxide membrane (SOM) to directly electrolyze metal oxides dissolved in a non-consumable molten salts. During the SOM electrolysis process, the desired metal such as magnesium, aluminum, silicon, or a rare earth is produced at the cathode while pure oxygen gas evolves at the anode. Compared with current state-of-the-art metal production processes, such as a chloride-based electrolysis process for magnesium production and the Hall–Heroult process for smelting aluminum, the SOM process brings various advantages such as simplified design, lower cost, lower energy use, and zero emissions. It provides a general route for producing various metals and has great potential to replace current metals, production processes. This paper examines the past and present progress of the SOM process, the challenges faced in commercialization, and the directions for future work.

Highlights

Today’s metals industry is a major consumer of carbonbased energy and generates a significant amount of pollutants including greenhouse gases (GHG) [1, 2]
This paper examines the past and present progress of the solid oxide membrane (SOM) process, the challenges faced in commercialization, and the directions for future work
The SOM-based electrolysis technology would produce metals (Me) from their respective oxides (MeOx) by the direct electrolysis reaction: MeOx ? Me ? x/2 O2, where x is the stoichiometric amount of oxygen in the metal oxide

Summary

Introduction

Today’s metals industry is a major consumer of carbonbased energy and generates a significant amount of pollutants including greenhouse gases (GHG) [1, 2]. The societal impetus to lower energy consumption and GHG emissions provides motivation for the development of clean technologies that could reshape the metals industry and enable environmental sustainability. To meet this challenge, we are developing a cost-effective, energy-efficient, and zero-emissions solid oxide membrane (SOM)based electrolysis process for the production of technologically critical metals. Finished products, the most energy-intensive step is usually the oxide to metal conversion. This step typically requires carbothermic, metallothermic, or halide reduction of the oxides. Over 90 % of the silicon (Si) production starts with carbothermic reduction

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