FULL ANSWER:
1. Air is filtered to remove the dust.
2. The air is cooled to -200 degrees celsius..
3. The water vapour condenses and is removed.
4. The CO2 (should be a small 2) freezes and is removed.
5. The liquefied air enters the column and is heated slowly.
6. The remaining gases are separated by fractional distillation.
7. Argon and oxygen have similar boiling points and so come out together; they are therefore separated using another column.