Oxygen

Oxygen, chemical formula O2, Chemical formula: 32.00, colorless and odorless gas, the most common elemental form on Oxygen element. Melting point -218.4 ° C, boiling point -183 ° C.

Oxygen gas is the most widely distributed in nature, accounting for 48.6% of the crustal mass. Oxygen is used for welding cutting, wastewater treatment, rocket propellant, and for animals and people to breathe in aviation, aerospace and diving.

The main components in the air are oxygen and nitrogen. Using the different boiling points in oxygen and nitrogen, the production of oxygen from air is called air separation. First, the air needs to be pre-cooled and purified (removing a small amount of moisture in the air, carbon dioxide, acetylene, and other impurities such as gas and dust), and then compressed and cooled to make it liquid air. Then, using the difference in boiling points of oxygen and nitrogen, the liquid air is repeatedly evaporated and condensed in the rectification column to separate oxygen and nitrogen to obtain pure oxygen (which can reach the purity of 99.6% ) and pure nitrogen (which can reach the purity of 99.9%). This is the most commonly used production method in the industry and there are also molecular sieve adsorption and point solution to produce oxygen.