What is dry ice and how is it made?

Dry ice is solid form carbon dioxide (CO2), which for common use sublimates at −79 °C, i.e. passes directly into gas form, without melting beforehand.

Dry ice is obtained by expanding carbon dioxide which had been previously liquefied under pressure. Part of the carbon dioxide evaporates, while the rest eliminates the heat necessary for the evaporation and thus cools down. This produces the so-called frozen carbon dioxide snow. Depending on the subsequent intended use, this will then be pressed into the desired shape.

To process description

Applied as a jet, dry ice comes in the form of rice grain sized granules (pellets), which are blasted at high speed (sound speed) onto the surface to be cleaned.

Three effects are used to this purpose:

Thermal energy
Temperature difference (cold shock -79 ° C) between layer of soiling and surface
Kinetic energy
The particles have a low hardness (2 on the Mohs scale) at high speed and do not damage the surface.
Mechanical energy
The pellets sublimate on contact with the surface to be cleaned, meaning that they pass from solid to gaseous state. The volume of the particles increases by up to 700 times.

The particles transfer the soiling and loosen it without damaging the surface. No water results from this process and no chemicals are needed. The surface is free of oil and grease.