Argon purification

In a process for air separation by low temperature rectification of air, in which air is compressed, prepurified, cooled, fed to a double rectification column comprising a high pressure column having a top and a bottom, said top being in heat exchange relationship with a low pressure column, and separated into an oxygen-rich and a nitrogen-rich fraction, and from the low pressure column of the rectification, an oxygen fraction enriched with argon is removed and, in a crude argon rectification, is separated into crude argon and a higher boiling residual fraction, the improvement which comprises conducting the crude argon rectification in a column having a head condenser, at least 150 theoretical plates, and provided with low pressure drop structured packings or fillings;

• and cooling the head condenser with liquid from the bottom of the high pressure column, said crude argon rectification resulting in a sufficient separation of oxygen to eliminate any use of a deoxo unit to remove oxygen from the resultant argon.