Solid CO2 (customarily known as “DRY ICE”)
Dry Ice is the product of processing liquid CO2 . If the pressure of liquid CO2 is suddenly released, a proportion of that liquid will change to the solid state (becoming dry ice “snow”) and the remainder will revert to gas (revert gas). When the snow is compressed under hydraulic or mechanical action, blocks or pellets of dry ice are formed. The revert gas (gaseous CO2 ) can be readily reclaimed and converted back to liquid by recompression and reliquefaction, thence returned to the dry ice block machine or pelletizer for further processing.
The temperature of dry ice is -79 °C (-110,2 °F) and in the atmoshere it will pass directly from the solid to the gaseous stage, leaving no moisture or trace of its presence except the cold.