What is Dry Ice?

Dry ice is a type of solid carbon dioxide that is widely used in many industrial and commercial applications. Unlike regular ice, which is made of water, dry ice is a frozen gas that turns directly from a solid to a gas when it sublimates. Also known as cardice, carbonic ice, or CO2 ice, it serves as an ideal solution for transporting perishable items, providing efficient refrigeration and cooling in lab or medical environments.

As a non-toxic and non-flammable substance, dry ice offers a clean, waste-free alternative to traditional cooling methods. Nevertheless, proper handling is crucial to avoid potential hazards, such as skin contact or insufficient ventilation, which can lead to oxygen displacement from released gas.

Properties of Dry Ice

The physical properties of dry ice make it unique and useful in many applications. It is extremely cold, with a temperature of -78.5°C, and it sublimates at room temperature. This means that it can be used to keep things very cold without the need for electricity or other forms of cooling.

How is Dry Ice Made?

The primary raw material for making dry ice is carbon dioxide (CO2) in liquid form. The gas is typically sourced from industrial processes like fermentation, ammonia production, or combustion. It is then purified, liquefied, and stored in high-pressure tanks.

Specialised equipment is required to make dry ice. This includes a liquefaction unit , which cools and compresses CO2 gas into a liquid state. An expansion chamber allows the liquid CO2 to expand, which results in rapid cooling and partial conversion to dry ice snow. Finally, a block press or pelletizer is used to compress the dry ice snow under high pressure to form solid blocks or pellets, depending on the desired form.

The process of making dry ice from CO2 gas is rather straightforward:

  1. Carbon dioxide (CO2) gas is sourced from industrial processes and purified.
  2. The purified CO2 gas is cooled and compressed into a liquid state using a liquefaction unit.
  3. The liquid CO2 is allowed to expand rapidly in an expansion chamber, which results in rapid cooling and partial conversion into dry ice snow.
  4. The dry ice snow is compressed under high pressure using a block press or pelletizer, forming solid blocks or pellets, depending on the desired form.

Throughout the process, safety precautions must be taken, including wearing protective gear and handling dry ice with care, as it can cause frostbite or cold burns upon contact with skin. Proper ventilation is also crucial to avoid dangerous levels of CO2 gas buildup.

Uses of Dry Ice

Dry ice is a versatile material with numerous applications across various industries. Some of the primary uses for dry ice include cleaning, blasting, food storage and transportation and scientific experiments. Dry ice is also used in special effects, pest control, fire suppression and emergency refrigeration.

Dry Ice Cleaning (Dry Ice Blasting)

Dry ice blasting is an effective, environmentally friendly cleaning method that uses small pellets of dry ice as a blasting medium. It is suitable for a wide range of applications, including:

  • Removing paint, rust and contaminants from surfaces
  • Cleaning delicate electrical components and machinery
  • Eliminating mould, mildew and bacteria

Dry ice blasting is often a preferred cleaning method due to the fact that there is no secondary waste to deal with, as dry ice sublimates upon impact, which leaves no residue. It’s non-abrasive, causing no damage to the underlying surface. It’s non-conductive, so it’s safe for use on electrical components, and it’s non-toxic.

Food Storage and Transportation

Dry ice is widely used in the food industry for preserving perishable items and transporting temperature-sensitive products. It’s particularly useful in this application due to its ability to maintain low temperatures. In the food industry, carbon dioxide is used as a cooling agent during transportation and storage of perishable items such as fruits, vegetables, and meat. Dry ice's extremely low temperature (-78.5°C/-109.3°F) helps prevent spoilage and bacterial growth. 

It also leaves minimal moisture behind. As dry ice sublimates, it does not produce any liquid, which in turn reduces the risk of contamination and spoilage.

Scientific Experiments & Laboratories

Dry ice has several applications in scientific research and laboratory settings. Commonly, dry ice is used as a cooling agent. Dry ice, with its extremely low temperature, is used to maintain low temperatures in various experiments and to cool down sensitive equipment. It is also employed in the storage and transportation of biological samples, chemicals, and pharmaceuticals.

Dry ice is also used in cryogenic studies, such as freezing and preserving biological specimens or tissue samples for later analysis.

When analysing environmental matrices for VOC contamination, dry ice may be used as a cooling agent in gas chromatography, a technique to separate and analyse volatile compounds.

Finally, dry ice is also used in cloud chambers. In particle physics, dry ice is utilised to create a cold environment within cloud chambers to visualise ionising radiation paths.

Other Uses of Dry Ice

Dry ice has some other unique applications as well. For theatrical fog and special effects, dry ice is placed in warm water to generate dense, low-lying fog by cooling the surrounding air and causing water vapour to condense. 

Dry ice can act as a fumigant, which eliminates pests like bed bugs, termites and rodents. It releases CO2 gas into affected areas, which displaces oxygen and suffocates the pests.

In specific situations, dry ice can extinguish fires, particularly electrical fires or those involving flammable metals. The CO2 released from dry ice displaces oxygen, suppressing combustion.

Another unique application of dry ice is as a temporary cooling solution during power outages or equipment failures, preserving perishable items or temperature-sensitive materials until alternative refrigeration becomes available.

Handling and Storing Dry Ice

The longevity of dry ice depends on its form, whether it is compressed as a block or pellets, size and storage conditions. On average, a block of dry ice can last 18-24 hours in an insulated container, while pellets may last 12-15 hours. However, how long dry ice lasts depends largely on insulation quality and environmental factors. 

Handling dry ice requires taking proper precautions. Be sure to always don protective gear - wear insulated gloves, safety goggles and long sleeves when handling dry ice to prevent frostbite or cold burns. 

You should work in a well-ventilated area when using dry ice, as it releases CO2 gas upon sublimation, which can cause asphyxiation in poorly ventilated spaces when working with concentrated amounts. 

Dry ice should be stored in an insulated container, such as a Styrofoam cooler or a dry ice storage chest. Avoid airtight containers as they can cause pressure build-up and may explode due to expanding CO2 gas.

Do not store dry ice in a regular freezer, as the low temperature may cause the freezer's thermostat to malfunction or shut off. Dry ice also needs proper ventilation to release CO2 gas.

Where to Buy Dry Ice in Australia

Supagas is a leading dry ice supplier in Australia, catering to various industries' needs with high-quality dry ice products. As a reliable and trusted provider, Supagas ensures strict adherence to safety and sustainability standards while delivering exceptional customer satisfaction. 

Our extensive distribution network and commitment to timely service make them an ideal choice for your dry ice requirements. Trust Supagas as your go-to dry ice supplier, offering premium products and unparalleled support to ensure a seamless experience. Contact us today for your dry ice needs.