Storage and Shelf Life
Storage of Solid Calcium Chloride Products
Solid calcium chloride is both hygroscopic and deliquescent. This means that the product can absorb moisture from the air, even to the point of converting to liquid brine. For this reason, protecting solid calcium chloride from excessive moisture exposure is the primary requirement to maintain product quality while in storage.
Opened packages should be tightly resealed after each use to prevent caking and liquid brine formation that may result from exposure to humid air. They should be stored in a dry place, but not in an attic, on shelves or in any area where the leakage of liquid brine could cause damage to ceilings and other building structure, as well as equipment or other items stored below.
Some types of bags do not seal well if stored standing on end, therefore unopened packages should be stored lying flat in a dry area. Valve bags need product pushing on the valve, which only happens if bags are lying down flat.
Palletized product covered by an intact plastic shroud may be stored outdoors on a well-drained asphalt or concrete surface. If the shroud is torn, pierced or removed, the palletized product should be stored indoors or under a waterproof covering. Packages that are typically not shrouded should be stored indoors or under a waterproof covering. Solid calcium chloride is temperature-stable under all ambient storage conditions.
Storage of Liquid Calcium Chloride Products
The preferred material of construction for large liquid storage tanks is carbon steel with an epoxy-based interior coating and a durable, high-quality coating on the exterior. Non-metallic materials, such as fiberglass or plastic, work well for smaller tanks storing product at ambient temperature. However, plastic tanks may lose strength at high temperature if used to make up solutions by dissolving solid calcium chloride.
Stainless steels are generally not suitable for liquid calcium chloride storage due to their vulnerability to chloride-induced stress cracking. Unlined carbon steel in continuous liquid calcium chloride service at ambient temperature is expected to corrode 10-20 mils per year, which may or may not be acceptable depending on the situation.
Containers constructed from 5454 or 6061 aluminum have been shown to passivate with time without suffering excessive corrosion and uneconomical service life.
For additional information related to proper storage and handling of calcium chloride products, see: Calcium Chloride: A Guide to Handling and Storage.