Carbon dioxide is normally recovered for industrial purposes from flue gases or as a by-product of ammonia or hydrogen production. It is unusual in that it only exists as a liquid under pressure and normally sublimes as a gas straight from its solid form.Like a number of other gases, carbon dioxide's inert qualities make it useful for preventing or suppressing combustion or oxidization. Its major use, however, is as a refrigerant or cooling agent. Solid carbon dioxide at -80°C is, like liquid nitrogen, used for chilling and freezing in the food industry.
The gas dissolves easily in water, making the resultant solution slightly acidic. As a result, it is often used to balance the pH of water in preference to the addition of mineral acids. Its solubility also makes it a chosen method for putting the "fizz" into drinks of all kinds.
Heavier than air, freezes to a solid at atmospheric pressure, liquefies under pressure, chemically acidic and water-soluble, does not support combustion.
Food freezing, chilling and refrigeration
Alkali neutralization, waste treatment
Inert gas pressurization
Oil well recovery
Carrier gas for deodorants, odorants, pesticides and the like Breathing stimulant