Chemical Surface Treatments for Steel Storage Tanks

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You have different material choices for your storage tank. Steel is a leading option for tanks meant for storage of a range of liquids and pressurized materials. This is because this material is durable, strong and withstands various types of chemical damage.

There are several treatments designed to increase the corrosion resistance of an above-ground steel tank. This way, your tank’s integrity remains uncompromised, and you minimize product contamination secondary to chemical reactions. Here are some of the chemical treatments used to protect your tank’s interior.

Pickling

This process uses acid treatments to reduce the high temperatures used for fabricating steel tanks in hot working and welding. Mixtures of nitric and hydrofluoric acids are the common ones used in pickling. The acids available as baths, gels and pastes react with the steel surface and dull and roughen it while getting rid of free iron particles, which contribute to corrosion.

Passivation

This process dissolves iron impurities from steel tank surfaces. These iron particles might react with those of steel and cause pitting corrosion on your tank’s surface. The commonly used option for passivation is a paste, gel or bath containing up to 50% nitric acid. Before use for your tank’s surface treatment, a small part of the tank is tested to guarantee the acid does not affect its appearance.

Electropolishing

This surface treatment method cleans the round valleys and peaks on your tank’s surface, which are at high risk of corrosion. Electropolishing uses sulphuric and phosphoric acids and a high current density for cleaning. It results in increased brightness and luster of your steel tank’s surface.

Most above ground tank owners pay considerable attention to their tank’s outer surface to ensure it remains aesthetically appealing. But the tank’s inner surface is just as important since this is the one in contact with your stored item. The above chemical treatments are sure to protect your tank’s interior from damage.