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Safety Measures for Storing Calcium Chloride

Bidisha Mukherjee Apr 20, 2019
Calcium chloride is an extremely corrosive compound, and needs to be handled with care. Here's how you can go about storing it safely ...
As the name suggests, calcium chloride is a chemical compound formed by Calcium and Chlorine. Its chemical formula is CaCl2. It is a chloride brine, and is moderately corrosive in nature. For that reason, special care should be taken for proper storage of the compound in the liquid state.

The Right Storage Tank Material

Generally, tanks made up of mild steel are used for the storage of calcium chloride. However, it is often found that the liquid turns brown or yellow when it comes in contact with mild steel. This is due to the release of iron ions in the liquid. To prevent such corrosion, it is advisable to coat the inside wall of the tank with materials like epoxy.
Tanks, that are made up of titanium, or some other exotic alloys are good, because they are corrosion-resistant, even at high temperatures. Their only disadvantage is that, they are very expensive. Hence, they are used only for certain special applications like heat exchanger plates.
Plastic materials like glass fibers are resistant to corrosion by calcium chloride. So, these can be used for the construction of storage tanks that are small in size.
When in contact with galvanized materials like zinc, calcium chloride produces hydrogen, which is highly inflammable. For this reason, it should not be stored in containers made up of these materials.
Steel with chromium content, like stainless steel, should not be used in the manufacture of storage tanks for the compound as it can cause pitting on the surface of the tank.

Storage Conditions

Corrosion is an oxidation process. Oxygen plays a vital role in aggravating the process of corrosion in calcium chloride. It has been observed that the storage tank is worst-affected where the surface of the liquid is exposed to air. So, air should not be allowed to come in direct contact with the liquid stored.
The compound in acidic form is a highly corrosive substance. It causes corrosion at a very rapid pace. So, it should ideally be kept in a neutral form. If required, some basic substance like sodium hydroxide or calcium hydroxide should be added to neutralize the compound.
The lower the concentration of Calcium, the higher is it solubility in Oxygen. Hence, it is better to store the compound in the concentrated form. Calcium chloride with a concentration above 30% is less corrosive, and is considered to be the ideal concentration of the liquid for storage.
The higher the temperature, the faster is the rate of corrosion. So, a low temperature of the storage place will help minimize corrosion. With proper care this compound can be stored away safely, and for long periods.