Dry ice is solid carbon dioxide that will sublimate directly from a solid to a gaseous state at room temperature without going through a liquid state. Dry ice has a temperature of -78.5°C (-109.3°F), extremely low temperatures make it an efficient coolant.
Dry ice is made from liquid carbon dioxide, which is expanded and cooled to form CO₂ snow, and they are compressed under high pressure into blocks, pellets or flakes of dry ice.
Dry ice does not ‘melt’, but sublimates directly into a gas. This process is called sublimation.
How long dry ice can be stored depends on the storage conditions. In a well-insulated container, dry ice can be stored for 24-48 hours. In an ordinary environment, dry ice will sublimate quickly.
Dry ice should be stored in insulated containers such as foam boxes or special dry ice holding tanks. Avoid completely sealed containers to prevent pressure build-up.
Dry ice itself is non-toxic, but direct contact with the skin can cause frostbite. In addition, the use of dry ice in confined spaces can lead to high CO₂ levels, which can affect breathing.
Dry ice is not recommended for use in household refrigerators or freezers. The extremely low temperatures of dry ice may cause the refrigerator temperature control system to malfunction.
Dry ice can be used for equipment cleaning, transporting and storing medicines at low temperatures, food preservation, stage smoke effects and other uses.