The atmosphere around earth is composed of 0.94% argon. Today, cryogenic fractional distillation isolates elemental argon from the air using extremely high temperatures to liquefy the air, and then extremely low temperatures to separate the argon from the liquefied elements. In this process, krypton, neon, nitrogen, oxygen, and xenon are produced.
Before technology was available to use cryogenic fractional distillation, elemental argon was isolated using a multi step system. The first step used an air separation distillation system and a low pressure column to isolate air with high concentrations of argon. The crude argon was heated and reacted with nitrogen and oxygen to form argon in water. The water was removed from the argon through condensation and absorption processes. The gas that remained was cooled to low temperatures in order to remove the small amounts of remaining nitrogen and hydrogen from the argon gas mixture. The end result was pure argon.
