Development of Hydrogen Plasma Reactor for Smelting and Reduction of Oxides

Electrification and hydrogen play a vital role in the decarbonization of heavy industries, including in minerals and metallurgical processing. Considering this, many researchers are re-investigating hydrogen plasma for a low-carbon technology for application in minerals and metallurgical processing. Hydrogen plasma (monoatomic H and ionic hydrogen H⁺) offers a thermodynamic advantage as it has a very high reductive potential and capacity for reducing stable compounds/oxides such as CaO, MgO, Al₂O₃ and rare earth oxides. This paper discusses the development of a unique hydrogen plasma reactor for reduction, smelting and refining of metals/materials at Swinburne University of Technology, called SwinH₂Plas. The reactor consists of a 35 kWhydrogen plasma torch, a specially designed 3D-printed copper shroud, a vertical reactor tube and powder collector. The plasma torch allows a continuous feed of powders; hence the reactor can be operated as a continuous process. The initial test of the reactor was carried out using iron oxides (naturally occurring magnetite and hematite) and partially reduced iron oxide as source materials. The results revealed significant iron formation with only 2% to 10% H₂ concentration in the gas mixture. Globular iron and slag and partially reduced particles with size 20–50 µm were obtained at the powder collector. Further optimization of operating conditions is being carried out for stable operation with high metallization and different oxides feed.