Physical properties of dry ice
Dry ice is the popular name of carbon dioxide (CO2) in its solid state. Dry ice is non-flammable, non-conductive and contains no water.
In 1835, the French chemist Charles Thilorier published the first ever description of dry ice. Upon lifting the lid of a large cylinder full of liquid carbon dioxide, he noticed that the carbon dioxide was evaporating fast and leaving a thick layer of dry ice in the cylinder. Over the next 60 years, dry ice was observed and tested by a number of scientists for the purpose of exploring all of its useful properties and potential applications.
Dry ice applications
Dry ice has multiple practical applications:
Preparation and recommendations for handling dry ice
Preliminary preparation for handling industrial quantities of dry ice
Plan ahead when you are going to need the dry ice as you will have to use it as quickly as possible. Dry ice changes from its solid to its gaseous state in the course of time. Ensure that the transportation vehicle or the room where you intend to work are well-ventilated.
When you work with large quantities of dry ice, as it converts back to its gaseous state it releases carbon dioxide into the atmosphere. This may present a hazard if work is carried out in a small and/or confined space. If you experience any sudden symptoms such as a headache, difficulty in breathing or blue lips or fingernails, you must immediately leave the room and/or let in some fresh air. In this case, getting fresh air is absolutely imperative as recirculated air will not be safe.
Ensure that you are wearing gloves while holding dry ice as it may cause frostbite. Keep an eye on any children nearby and never leave dry ice unattended.
Choose a proper container
Store the dry ice in a thick isolated container, e.g. made of expanded polystyrene, but remember not to seal the container as carbon dioxide evaporation may cause the pressure to rise inside the vessel. Store the container in a well-ventilated space and do not place dry ice in a freezer or refrigerator. Its thermostat will shut down due to the extremely low temperature dry ice can create.
Handle dry ice with caution
Put on your gloves and carefully open the dry ice container. Then, using your hands or a suitable instrument, take out the pellets or block of dry ice and place them/it on a soft surface, e.g. fabric, a plastic surface or a concrete floor (tiled flooring or other hard surfaces may be damaged by the cold temperature).
When you are ready to dispose of the dry ice, just take it out of the insulated container and leave it unpacked on a soft surface so that it can be aerated. It will then evaporate (sublimate). Ensure in advance that the room is well ventilated. Ventilate all storage spaces and rooms where you store dry ice, as carbon dioxide is heavier than air and sinks to low-lying parts of non-ventilated spaces.