Dry ice is frozen carbon dioxide. A block of dry ice has a surface temperature of -109.3 degrees Fahrenheit (-78.5 degrees C). Dry ice also has the feature of sublimation. As it breaks down, it turns directly into carbon dioxide gas rather than a liquid. The super-cold temperature and the sublimation feature make dry ice great for refrigeration of all types of items. For example, if you want to send something frozen across the country, you can pack it in dry ice. It will be frozen when it reaches its destination, and there will be no messy liquid left over like you would have with normal ice.
If you ever have a chance to handle dry ice, you want to be sure to wear heavy gloves. The super-cold surface temperature can easily damage your skin if you touch it directly. For the same reason, you never want to taste or swallow dry ice, either.
Another important concern with dry ice is ventilation. You want to make sure the area is well-ventilated. Carbon dioxide is heavier than air, and it can concentrate in low areas or enclosed spaces (like a car or a room where dry ice is sublimating). Normal air is 78% nitrogen, 21% oxygen and only 0.035% carbon dioxide. If the concentration of carbon dioxide in the air rises above 5%, carbon dioxide can become toxic. Be sure to ventilate any area that contains dry ice, and do not transport it in a closed vehicle.
To manufacture dry ice, gaseous carbon dioxide (CO2) is first pressurized and refrigerated to form liquid CO2, which is allowed to expand in an atmospheric chamber. When CO2 converts from liquid CO2 to gas, there is an extreme drop in temperature. This causes some of the gas to freeze, yielding both snow-like CO2 and vapor CO2. The “snow” is then hydraulically pressed into dry ice blocks and pellets.
The CO2 vapor produced during the production of dry ice is captured and recycled using a recovery system to maximize the yield of dry ice from each pound of liquid CO2. This is the most cost-effective way to produce dry ice, a cost savings we pass on to our dry ice customers.
Dry ice gives off CO2 into the air, so if dry ice has been in a closed car, van, or room for more than 10 minutes, open the doors and windows before entering. Otherwise, you will experience difficulty breathing. Leave the area immediately if you start to breathe quickly or have any difficulty breathing.
Store dry ice in an insulated container. Do not store ice in a container that is completely airtight. As the ice changes to CO2 (carbon dioxide) gas, it will cause an airtight container to expand and possibly explode.