Flushing block is the normal term for a porous bottom block, through which gas can be introduced into the melt in furnaces or a ladle. The melt is usually flushed with argon. The gas is fed into the melt at low pressure, and removed from the melt by the partial pressure reduction of other gases. The blowing in of flushing gas (including nitrogen) can also be used to stir or mix the melt with added reaction materials, e.g. carburisation and desulphurisation agents.
When melting chrome-nickel alloys in the crucible induction furnace, flushing
with argon can significantly reduce the melting and alloying times.
In the case of light metals and zinc, a higher melting performance can be
achieved with the aid of a nitrogen flushing lance due to the intensive movement
of the bath.