Direct electrochemical reduction of hematite pellets in alkaline solutions
Journal article
Submitted version
Permanent lenke
http://hdl.handle.net/11250/2464222Utgivelsesdato
2014Metadata
Vis full innførselSamlinger
- Institutt for materialteknologi [2596]
- Publikasjoner fra CRIStin - NTNU [38881]
Sammendrag
Our previous studies on the electrowinning of iron from hematite particles suspended in sodium hydroxide solutions demonstrated that iron was produced through a direct solid phase electrochemical reduction of the oxide particles. This suggests that the electro-deoxidation of a hematite powder pellet by the FFC type process should be possible in aqueous solutions at a low temperature. We investigated the electrochemical reduction of a solid hematite pellet cathode manufactured by conventional mechanical pressing followed by sintering process in concentrated sodium hydroxide solutions using a nickel inert anode at 110 °C. The experimental results indicated that hematite was reduced to iron metal. Propagation of the reduction reaction front through the oxide phase occurred at a high speed, and the rate-determining step was the diffusion of the oxygen ion through the shrinking cores of the oxide particle.