The production of iron using hydrogen as a reducing agent is an alternative to conventional iron- and steel-making processes, with an associated decrease in CO₂emissions. Hydrogen plasma smelting reduction (HPSR) of iron ore is the process of using hydrogen thermal plasma to reduce iron oxides. A laboratory-scale hydrogen plasma facility, which is called ‘Plasmette’, has been installed as an early-stage means to assess the characteristics of the new technology. In this process, the plasma arc is generated between the tip of the hollow graphite electrode as the cathode, and the ignition pin, located in the steel crucible, as the anode. The mode of the arc attachment is DC transfer. The steel crucible is electrically connected to the bottom electrode. Argon or nitrogen can be used as a plasma gas and hydrogen as a reducing agent. A mixture of gas containing argon (or nitrogen) and hydrogen is injected into the plasma arc zone through the hollow graphite electrode. There are different orifices on the reactor body. One of them is employed to install an optical spectrometer to monitor the light from the arc. The plasma vessel and the electrode holder are equipped with a water-cooling system to avoid heat penetration from the heating sections. A mass spectrometer, GAM 200 produced by InProcess Instruments Gesellschaft für Prozessanalytik mbH, is used to analyse the chemical composition of the off-gas. Furthermore, Plasmette is also equipped with a continuous feeder to feed the powder mixture of iron ore and additives to study the reduction behaviour of the iron ore.

Technical data:

• Electric power: 3.5 – 8 kW, voltage: 20 – 100 V, amperage: 80 – 150 A
• Arc length: 1 – 6 cm
• Maximum capacity of steel crucible: 200 g
• Continuous feeding system: Hi-Doser 1l powder dosing instrument produced by LAMBDA Laboratory Instruments
• Gases: H₂ (0-10 l/min), Ar (0-10 l/min) and N₂(0-20 l/min)provided via mass flow controllers of Bronkhorst high-tech B.V.