Dry ice is simply carbon dioxide that has been frozen. The surface temperature of a block of dry ice is -109.3 degrees Fahrenheit (-78.5 degrees C). Dry ice also has the advantage of sublimation, which means that as it degrades, it converts directly into carbon dioxide gas rather than a liquid. Dry ice is ideal for refrigeration due to its super-cold temperature and sublimation feature. If you want to send something frozen across the country, for example, you can pack it in dry ice. When it arrives at its destination, it will be frozen, and there will be no messy liquid left over, as there would be with regular ice.
Many people are familiar with liquid nitrogen, which has a boiling point of -320 degrees Fahrenheit (-196 degrees C). Liquid nitrogen is a messy and difficult substance to work with. So, what makes nitrogen a liquid and carbon dioxide a solid? This distinction is due to nitrogen and carbon dioxide’s solid-liquid-gas properties.
We are all familiar with water’s solid-liquid-gas behaviour. We know that at sea level, water freezes at 32 degrees Fahrenheit (0 degrees Celsius) and boils at 212 degrees Fahrenheit (100 degrees C). Water, on the other hand, behaves differently as pressure is increased. The boiling point decreases as the pressure is reduced. Water will boil at room temperature if the pressure is reduced sufficiently. When you plot the solid-liquid-gas behaviour of a substance, such as water, on a graph that includes both temperature and pressure, you create a phase diagram for the substance. The phase diagram depicts the temperatures and pressures at which a substance transitions from solid to liquid to gas.
Carbon dioxide moves directly between gas and solid at normal pressures. Liquid carbon dioxide is only found at much higher pressures. Liquid carbon dioxide can be found in a high-pressure carbon dioxide tank or a carbon-dioxide fire extinguisher, for example.
Temperature of Dry Ice
To create dry ice, begin with a high-pressure container filled with liquid carbon dioxide. When you remove the liquid carbon dioxide from the tank, the expansion of the liquid and the rapid evaporation of carbon dioxide gas cools the remaining liquid to the freezing point, where it solidifies. You’ve probably seen this carbon dioxide snow form in the nozzle of a carbon dioxide fire extinguisher.
Dry ice sublimates at temperatures above 109.2 °F, so you must use it quickly or storeit at temperatures below -109.2 °F because,unlike regular ice, it turns into a gas rather than a liquid.
Storing Dry Ice
Dry ice should be stored outside in a well-insulated container, such as a cooler, with the lid only partially closed. The thicker the insulation, the slower it will decompose back into a gas. Never store it in a closed container because the sublimated CO2 gas will sink and become dangerous. If it is airtight, it can be used to create a dry ice bomb, causing the container to explode. You may believe that the freezer is an excellent place to keep things cool, but it is actually too warm. Because of the low temperature of dry ice, your refrigerator may turn off.
Uses of Dry Ice in Many Industries
- Medical Industry
Dry ice is frequently used in the medical industry to store organs for transplant as well as in minor dermatology surgeries such as mole removal, wart removal, and other skin imperfections.
- Food Industry
Dry ice pellets are used in the food industry to prevent bacterial growth during large-scale blending or grinding processes such as hamburger production.
- Deep Cleaning
Dry ice blasting machines are used for deep cleaning to remove mould, glue, paint, oil, grease, and other difficult to remove adhesive materials.