Purpose of Soda Lime

Soda lime is generally composed of the chemicals calcium hydroxide, sodium hydroxide and potassium hydroxide. It presents in the form of grayish white granules. Its main property is its ability to absorb carbon dioxide and water vapor, making it a much-used product in the medical field. Being highly corrosive, soda lime must be used with extreme caution; it is harmful when inhaled and its accidental ingestion could cause severe damage to the gastrointestinal tract and even death.

Medical Use

• Soda lime is used medically to absorb carbon dioxide.

  In the medical field, soda lime is used in general anesthesia. In this case, the patient's expired gases are not removed by simply voiding the exhaled gases from the system, but rather by passing them through a canister filled with soda lime granules. This allows the granules to absorb the carbon dioxide, allowing the expired gas to be inhaled again. Medical grade soda lime contains a special dye which changes color to alert that its carbon dioxide absorbing capacity is being lost.

Undersea Use

• Soda lime helps remove carbon dioxide during deep sea diving.

  In a similar fashion, soda lime is used for diving equipment to remove harmful carbon dioxide from the breathing circuit. The calcium hydroxide found in soda lime reacts with the carbon dioxide found in the breathing circuit, and removes it, preventing it from building up to dangerous levels. Soda lime is typically contained in the absorber unit, also know as the scrubber, where it converts gaseous carbon dioxide into solid calcium carbonate. Soda lime cartridges are also used to remove carbon dioxide from submarines.

Mining Use

• Soda lime may save lives when used in mine refuge chambers.

  Soda lime also provides its life-saving properties in the mining industry. When enclosed in a small area such as in a mine refuge chamber, the carbon dioxide emitted by the miners as they breath may accumulate to dangerous levels, according to the Centers for Disease Control. A scrubber system often using soda lime is installed in mine refuge chambers to prevent carbon dioxide poisoning. It is important for miners to learn how to replace the soda lime cartridges properly to avoid the unnecessary and dangerous build-up of carbon dioxide.

Industrial Use

• Soda lime can also effectively absorb moisture, and therefore it can be used for industrial and commercial use as a drying agent, or desiccant. Because of these properties, soda lime tends to deteriorate fairly quickly; therefore, it must be kept in airtight containers. When used to absorb moisture, soda lime has a high moisture absorption rate and presents in low cost packets ideal for absorbing moisture from clothing, footwear and leather goods.