What changes does industrial oxygen production belong to?

Industrial oxygen production is a physical change.

Industrial oxygen production:

Hydrogen peroxide or potassium permanganate is commonly used in the laboratory to produce oxygen, which has the characteristics of fast reaction, simple operation and easy collection, but it is expensive and cannot be produced in large quantities, so it can only be used in the laboratory.

Industrial production needs to consider whether raw materials are easily available, whether the price is cheap, whether the cost is low, whether it can be produced in large quantities and its impact on the environment. The air contains about 2 1% oxygen, which is a cheap and easily available raw material for oxygen production. Liquid air fractionation is widely used in industrial large-scale production of oxygen, and oxygen is separated by using the different boiling points of oxygen and nitrogen.

A large amount of oxygen used in industry is mainly produced by liquefying air and then separating liquid air. Physical change air consists of oxygen, nitrogen and other gases. How to separate oxygen from the air? We know that any liquid substance has a certain boiling point.

Scientists use this property of matter to pressurize at low temperature, so that air can be transformed into liquid air and then evaporated.

Because the boiling point of liquid nitrogen is-196℃ (77K), which is lower than that of liquid oxygen, nitrogen first evaporates from liquid air, and the rest is mainly liquid oxygen. In order to facilitate storage, transportation and use, oxygen is usually pressurized to 1.5× 107 Pa and stored in a blue hard bottle.