The raw argon column is fed by the oxygen-argon mixture from the low-pressure column of an air separation plant (Fig. 1). Here, raw argon (at the top of the column) is separated from an argon-oxygen mixture that is reintroduced into the low-pressure column. The gaseous raw argon at the top of the column is partly liquefied in the condenser and reintroduced into the raw argon column as washing material. Vaporizing raw oxygen is used as coolant in the condenser and afterwards introduced into the low-pressure column. The process ensures that no hydrocarbons accumulate.

The part of the raw argon that is not liquefied is introduced into the raw argon liquefier. The raw argon is liquefied by vaporizing nitrogen and flows into the raw argon column. There, the residual nitrogen in the material is removed. The final product, highly pure liquid argon is discharged and introduced into the liquid argon tank.