Abstract: For extracting argon, air is separated in a rectifying system comprising at least one air separating column and one crude argon column. An argon-containing oxygen fraction is taken from the air separating column and is introduced into a crude argon column. In the upper area of the crude argon column, a crude argon fraction is removed and a first reflux liquid is charged. A first residual fraction is taken from the lower area of the crude argon column. The crude argon fraction is introduced into the lower area of a semipure column. In the upper area of the semipure column, an argon fraction is taken which has reduced oxygen, and a second reflux liquid is charged. From the lower area of the semipure column, a second residual fraction is taken which forms the first reflux liquid for the crude argon column.