Entwicklung einer Gleichstrom‐Lichtbogenversuchsanlage zur Plasmaschmelzreduktion. Beschreibung des Reduktionsablaufes anhand mikroskopischer Untersuchungen und Bestimmung des Einflusses verschiedener Parameter auf den Reduktionsfortschritt.
Investigations of the plasma smelting reduction of iron ore have been carried out on a laboratory scale using a transferred argonhydrogen plasma arc. Pyrometric measurements show that the surface temperature near the arc foot is about 2600 K when the hydrogen is mixed with the plasma-gas in front of the cathode, about 2250 K when the hydrogen is introduced laterally into the arc and ca. 2150 K when a pure argon plasma is used. With the help of thermodynamic plasma data the corresponding arc temperatures have been estimated to be 13 000 K. 11 000 K and 9500 K.lt has been shown that the reduction rate after the smelting phase remains constant and is practically independent of the manner of addition of the hydrogen. The measured efficiencies of utilization of hydrogen were 43 % and 50 % and thus correspond closely to the equilibrium FeO + H 2 = Fe+ H 20. A combination of the rate constants obtained for the plasma smelting reduction with those found in literature for lower temperatures leads to an activation energy of approximately 67 kJ/mol. This value lies in the range of energies reported for the reduction of wustite after precipitation of the iron phase. It is therefore not unlikely, that in the case of plasma smelting reduction also, the rate determining step is the reaction Had +OH ad -+ H 2 0 Bd•
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