This invention relates to an improved process for the cryogenic separation of air and particularly with respect the separation of air in oxygen enriched zones within a distillation column. The improvement resides in utilizing aluminum packing in structured or random form in the oxygen enriched zones wherein the oxygen concentration ranges from about 80 to 96% by volume and optionally a sheet copper packing of structured or random form in the oxygen enriched zones, wherein the oxygen concentration is greater than 97% by volume. The aluminum packing may also be used in an argon column where argon is separated from oxygen by distillation.