Nitrogen is used in large quantities in the chemical industry for blanketing, purging and pressure transfer of flammable chemicals.
High purity nitrogen is used in large quantities by the semiconductor industry as a purge or carrier gas as well as for blanketing equipment such as furnaces when not in production.
Nitrogen is a colorless, odorless, tasteless and non-toxic inert gas. Liquid nitrogen is colorless. The relative density of gas at 21.1℃ and 101.3kPa is 0.967. Nitrogen is not flammable. It can combine with some particularly active metals such as lithium and magnesium to form nitrides, and can also combine with hydrogen, oxygen and other elements at high temperatures. Nitrogen is a simple asphyxiant.
Nitrogen is produced in large quantities at air separation plants which liquefy and subsequently distil air into nitrogen, oxygen and usually argon. If very high purity nitrogen is required the nitrogen produced may need to go through a secondary purification process. The lower range of nitrogen purities can also be produced with membrane techniques, and medium to high purities with pressure swing adsorption (PSA) techniques.
| Gas | Nitrogen/Liquid nitrogen |
| CAS No. | 7727-37-9 |
| Purity | ≥99% |
High-purity nitrogen is used as protective gas and carrier gas in the manufacture of integrated circuits, semiconductors and electric vacuum devices. In processes such as epitaxy, lithography, cleaning and evaporation, high-purity nitrogen is used as a gas for replacement, drying, storage and transportation. In aerospace technology, liquid hydrogen filling systems must first be replaced with high-purity nitrogen and then with high-purity helium.
