RH Recirculation Degasser

The main feature of the recirculation degassing process is the immersion of two nozzles, the up-leg and the down-leg, into the liquid steel.

The steel is induced into the vacuum vessel by injecting argon into the up-leg. The dissolved gases and argon are then released into the vacuum.

The degassed steel returns to the ladle via the down-leg. Alloying is carried out under vacuum without the effect of a slag reaction.

The additions are made via a 2-chamber vacuum lock of proven design. Temperature losses are minimal due to the vacuum vessel being held at high temperatures between treatments.

Advantages:

• Rationalisation of the primary melting production.
• Fast vacuum carbon deoxidation reaction.
• Vacuum decarburisation to less than 15 ppm C.
• Degassing (hydrogen removal).
• No need to tap slag free.
• Independent of ladle freeboard.
• Achievement of narrow temperature and analysis ranges.
• High recoveries of elements with large or small additions of alloying materials.
• Effective and rapid temperature and analysis homogenisation.
• Excellent separation of non-metallic inclusions.

Design variations:

• fixed vessel installation (ladle lifting system)
• movable vessel installation (vessel lifting system)
• fast vessel exchange system for increased availability
• duplex vessel installation for increased availability