Safely Storing Nitric Acid in Crosslinked Polyethylene Tanks: An Essential Practice for the Chemical Industry

Nitric acid, commonly known as HNO3, plays a crucial role in various industries, particularly in the chemical sector. Its applications range from manufacturing fertilizers and explosives to producing dyes and pharmaceuticals. 

However, due to its corrosive nature, proper storage and handling are essential to ensure safety. When fully concentrated, nitric acid (HNO3) is a clear acid with a sharp, pungent odor. If you’re working with a versatile, corrosive substance like nitric acid, it’s important that you find a suitable storage solution.

In this article, we’ll explore the importance of storing nitric acid in crosslinked polyethylene tanks and discuss its main uses in the chemical industry.

Main Uses of Nitric Acid in the Chemical Industry

Nitric acid is most commonly seen in the production of fertilizers for plants and grass, as it neutralizers with ammonia to form ammonium nitrate. While normally clear, nitric acid turns into a brownish-yellowish solution when decomposed in water, nitrogen dioxide, and oxygen.

Other uses of nitric acid include:

• Explosives Manufacturing — Nitric acid is utilized in the production of explosives, such as trinitrotoluene (TNT) and nitroglycerin. These materials find applications in mining, construction, and military operations.
• Metal Processing — Nitric acid is commonly used in metal processing for etching, pickling, and passivation. It helps remove impurities and oxide layers from metal surfaces, improving their appearance and corrosion resistance.
• Dye and Pigment Production — The chemical industry employs nitric acid in the synthesis of dyes and pigments. Nitration of aromatic compounds using nitric acid leads to the formation of vibrant and long-lasting colorants.
• Pharmaceutical Manufacturing — Nitric acid plays a role in the production of pharmaceuticals, including antibiotics, dyes, and certain chemicals used in medical research. It is used in various processes, such as formulation, purification, and synthesis.
• CIP / Water - Nitric acid is commonly used in cleaning-in-place (CIP) to remove scale build-up and prevent further mineral precipitation. During wastewater equipment cleaning, during water treatment, and after caustic washing, it can be added as an effective sequestering agent.

Nitric Acid Storage Recommendations

As with all acids, the concentration of the nitric acid solution determines the limitations of your chemical storage solution. The stronger the concentration, the more careful you must be with the chemical.

At Poly Processing Company, our polyethylene chemical storage tanks can hold concentrations of nitric acid up to 49%. If your concentration falls between 0 and 29%, it can be stored in a more robust high-density cross-linked polyethylene (XLPE) tank or a linear polyethylene tank in smaller sizes. 

Any of our stainless steel, titanium, or PVC fittings will work for storing nitric acid, but we do not use alloy 400 fittings or gaskets made out of buna, EPDM, or neoprene because of the potential for corrosion.

For nitric acid with a concentration of between 30 and 49%, we strictly use our XLPE tanks, because they have several advantages over tanks made with linear polyethylene. Storing these stronger concentrations should not be done at temperatures above 100° F. 

Our guidelines for fittings and gaskets are the same as they are for nitric acid with a concentration of between 0 and 29%, except alloy 400 can be used for the bolts on tank fittings used to store this higher concentration of nitric acid.

Safely Storing Nitric Acid in Crosslinked Polyethylene Tanks

Nitric acid is highly corrosive and can cause severe burns if it comes in contact with skin, eyes, or respiratory passages. To prevent accidents and ensure safe storage, many industries have turned to crosslinked polyethylene (XLPE) tanks. These tanks provide a cost-effective and durable solution for storing nitric acid.

Benefits of using XLPE tanks to store nitric acid include:

• Chemical Resistance — Crosslinked polyethylene tanks exhibit excellent resistance to a wide range of chemicals, including nitric acid. They effectively prevent leaks and chemical degradation, ensuring the safety of personnel and the environment.
• Durability — XLPE tanks have high impact strength and are resistant to cracking, which eliminates the risk of tank failure. They provide long-term storage solutions, reducing the need for frequent replacements.
• UV Stabilization — Nitric acid can be sensitive to ultraviolet (UV) light. XLPE tanks come with industry leading robust UV stabilizers to protect the stored acid from degradation caused by sunlight exposure.
• Thermal Resistance — Nitric acid has the potential to generate heat when stored at high concentrations. XLPE tanks can withstand elevated temperatures without compromising structural integrity, ensuring the chemical remains safely stored.

Our Approach to Nitric Acid Storage

Nitric acid is a versatile chemical with numerous important applications in the chemical industry. Safely storing this highly corrosive substance is paramount. Crosslinked polyethylene tanks offer an effective solution, ensuring the safety of personnel and the environment while facilitating the production of various products. 

All of our guidelines for the storage of nitric acid are based on several industry standards from leading publications. We have carefully checked our chemical resistance chart against these resources to ensure that it is as accurate as possible.

For more information about how we can help you store nitric acid safely without compromising the integrity of this valuable substance, contact a chemical storage tank expert today.