In addition to oxygen, nitrogen and inert gases, there are carbon dioxide gas and water vapor in the air.

Air has a certain effect on the buoyancy of minerals:

(1) After the mineral is crushed, the new surface is exposed, and it will be hydrated when it meets water, showing hydrophilicity. However, when the gas is adsorbed to the mineral surface, hydration is weakened, resulting in an initially hydrophobic surface;

(2) The use of gas and mineral surfaces is selective. Among them, oxygen has a greater influence on the mineral surface;

(3) The role of oxygen is beneficial to the hydrophobicity of sulfide ore. But if left on for too long, the mineral surface becomes hydrophilic. When the gas adsorption conditions are suitable, the surface of the mineral is hydrophobic, and it can be floated even without adding a flotation agent (such as dry coal powder).