Carbon Dioxide
Carbon dioxide's inert qualities make it useful for preventing or suppressing combustion or oxidisation. It is also used as a refrigerant or cooling agent.
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.
Properties
- Colourless
- Odourless
- Slightly acid-tasting gas
- Heavier than air
- Freezes to a solid at atmospheric pressure
- Liquefies under pressure
- Water-soluble
- Does not support combustion
Applications
- Food freezing, chilling and refrigeration
- Fire suppression
- Alkali neutralisation, swimming pool water treatment, waste treatment
- Mould setting
- Inert gas pressurisation
- Beverage carbonation
- Oil well recovery
- Plant growth
Physical Properties
| Gas | Carbon Dioxide |
| Chemical formula | CO2 |
| Molecular weight | 44.0 |
| Gas density | 1.87 Kg/m3 |
| SG vapour | 1.53 |
| Boiling point | -78.5°C |
| Critical temperature | -30.1°C |
| Critical pressure | 73.8 bar |
Production
Carbon dioxide is produced in a variety of ways. It can be produced by either combustion or oxidation of materials containing carbon (e.g. coal, wood, oil, etc.), by fermentation of sugars, or by the decomposition of carbonates under the influence of heat or acids. Commercially, carbon dioxide is recovered from the fermentation processes and as a by-product in the commercial production of ammonia.
Safety
Carbon dioxide in high enough concentrations may cause asphyxiation and death. Because it is heavier than air it will collect in low lying areas and therefore can be particularly dangerous when used in confined spaces. Carbon dioxide can also lead to cold burns as it is a very cold gas and when solid it can burn skin. Another safety issue is carbon dioxide’s slightly corrosive nature when wet. For more details on the hazards associated with carbon dioxide check the Safety Data sheet.