Abstract: A process for producing krypton and xenon. The concentrations of krypton and xenon contained in liquid oxygen are not highly increased in a concentrating column to produce concentrated liquid having a relatively low concentration of methane, which is stripped of methane by contact with oxygen gas in a methane purging column to reduce the methane concentration and the methane-purged liquid is then concentrated at the lower part of the purging column. Then, the concentrated liquid is vaporized and purified by catalitic combustion and adsorption, and thereafter a mixture of krypton and xenon is separated from the purified gas in a second concentrating column.

Abstract: A process for producing krypton and xenon in which relation to the air separation plant is restricted to receipt of liquid oxygen as raw material of krypton and xenon and return of liquid oxygen produced by the process. Heat which is necessary for rectification is provided by an argon recycle system.