Let’s start with a definition of what this thing is…
Dry ice isn’t really an ice at all.

In reality, it’s merely a frozen gas, carbon dioxide gas to be precise. As a result, we can’t conceive of this strange substance in the same way we think of ice, because it doesn’t melt but rather’sublimates.’

The act of transforming (relatively) hard, frozen CO2 ‘dry ice’ pellets back into a gaseous vapour is known as sublimation. When the frozen gas collides with an item or surface that has a larger mass than the pellets, sublimation happens. Sublimation causes the pellets to vanish totally into gas.

Dry ice is created by filling a high-pressure container with liquid carbon dioxide. The liquid CO2 is then carefully extruded from the tank, where the expansion of the liquid and the high-speed evaporation of CO2 cools the liquid below the freezing point, where it solidifies. This solid can be made into blocks, pellets, or even a snowy substance.

You’ve probably seen this carbon dioxide’snow’ build in the nozzle of a carbon dioxide fire extinguisher in operation. The compressed CO2’snow’ progressively sublimates as the ambient air temperature and low pressure enable it to revert to a gas.

What is the process of blasting dry ice?

So now we know how liquid CO2 may be extruded under high pressure to generate CO2 pellets. The pelletized CO2 is kept in insulated containers until it’s time to blast clean.

The pellets are initially put into a hopper, which mixes air pressure (usually supplied by a commercial air compressor) with the pellets and sends the air/pellet combination towards a ‘gun.’ In this example, the ‘gun’ is just a nozzle operated by a trigger or switch that allows the user to aim and regulate pressurised air and CO2 pellets flow.

The pellet and compressed air combination is pushed at rates ranging from 80 to 350 pounds per square inch. Low speeds are employed for sensitive, low-volume cleaning operations, whereas higher speeds are required for cleaning hard pollutants and extensively contaminated substrates.

The pollutants are ‘flash-frozen’ as the pellets and compressed air impact the thing to be cleaned. The link between the substrate surface and the contamination that we want to get rid of is broken by the flash-freeze procedure. The contaminant is subsequently ‘blown’ off the substrate by the air pressure, and it simply falls to the floor. After that, the debris may be cleaned up and securely disposed of in compliance with local regulations and ordinances.