Dry ice is the solid form of carbon dioxide. Its appearance is similar to water ice, but it freezes at a much lower temperature. Unlike water ice it melts directly to a gas, which leaves no liquid residue. It has many important applications such as refrigerating and flash freezing food. It is important to be aware that dry ice can cause skin damage with prolonged exposure. Let’s take a look at how dry ice is made.
How is dry ice made?
Although the process for making dry ice is not quite as simple as freezing liquid carbon dioxide, it actually isn’t overly complicated. The first step in producing dry ice is to obtain concentrated carbon dioxide gas. This is often the byproduct of other manufacturing processes, such as producing ammonia from nitrogen. The carbon dioxide gas is then pressurized and refrigerated to create liquid carbon dioxide. When the pressure is released some of the carbon dioxide vaporizes and this causes an extreme drop in temperature. This causes some of the remaining carbon dioxide to freeze with a snow like consistency. This carbon dioxide “snow” is then compressed into solid blocks or small pallets of dry ice.
Did you know?
It is not possible to make dry ice with equipment in the home. However, it is readily available for purchase.
Dry ice can be used to make ice cream. The following video shows how to do this at home.