Nitric Acid

Nitric acid is a strong mineral acid and oxidizer, and this product is a 20% solution by weight in water (CAS 7697-37-2), Technical Grade, at a dilute, controlled strength.

Concentration matters more with nitric acid than almost any other, because its oxidizing power scales sharply with strength. This 20% solution is well below concentrated nitric acid at roughly 68 to 70% and far below fuming grades above 86%. At 20%, the acid is a clear, mobile liquid that is easier to handle and does not carry the oxidizer transport subsidiary that higher-strength nitric acid does.

The dilute strength makes it a practical choice for stainless-steel passivation, controlled pickling, and metal cleaning, where full-strength acid would be unnecessarily aggressive. Choose 20% when your process is designed around a milder nitric feed or when you want lower fuming and simpler handling.

Nitric acid is sold across a strength ladder, and this 20% Technical Grade solution sits at the dilute end, well short of concentrated and fuming grades. Strength dictates both acidity and oxidizing behavior.

• 20% solution (this product) - dilute, controlled acid for passivation and pickling.
• Concentrated ~68-70% - the standard strong nitric acid, a vigorous oxidizer.
• Fuming (>86%) - red or white fuming acid for specialized oxidizing duty.

Nitric acid is supplied only as an aqueous solution and is normally colorless, though it can develop a faint yellow tint from dissolved nitrogen oxides over time. Technical Grade indicates industrial purity suited to manufacturing and metal-finishing work rather than analytical use. Note that dilute nitric acid behaves quite differently from concentrated acid toward metals, so do not assume a recipe written for one strength transfers to the other. Buying at a fixed 20% gives you consistent, repeatable behavior.

20% nitric acid is used primarily for stainless-steel passivation, metal pickling and cleaning, and controlled acidification where a dilute oxidizing acid is required. Its lower strength makes it the preferred choice for surface work that concentrated acid would over-attack.

• Stainless-steel passivation to restore and enhance the protective oxide layer.
• Metal pickling and brightening of stainless and other alloys.
• Equipment and surface cleaning where an oxidizing acid is specified.
• pH adjustment and acidification in industrial processes.
• General laboratory and manufacturing acid demand at scale.

Because the concentration is standardized at 20%, results are consistent from batch to batch. Always run a small test on a coupon or sample of your actual material first, since nitric acid reacts differently with different metals, and confirm the strength and contact time match your finishing specification before scaling up.

Store 20% nitric acid in a cool, dry, well-ventilated area in its original sealed HDPE or polyethylene container, shielded from direct sunlight and heat. A range of roughly 4 to 30 °C is ideal, since heat and light accelerate slow decomposition to nitrogen oxides.

Because nitric acid is an oxidizer as well as an acid, storage separation is critical. Keep it well away from organic materials, solvents, combustibles, bases, and reducing agents, as these combinations can react vigorously. Use secondary containment and acid-rated, vented closures.

• Keep containers off bare metal and incompatible surfaces.
• A yellow tint indicates dissolved nitrogen oxides, not spoilage.
• Do not store near flammable liquids or paper and wood products.

The 20% solution remains liquid down to near -20 °C, so protect it from hard freezing while keeping it cool.

Nitric acid 20% has a long shelf life, generally two or more years, when stored sealed in a cool, dark, compatible container. The acid is stable but does slowly decompose in light and heat, releasing nitrogen oxides that tint it yellow.

That yellowing is the main visible change over time and does not by itself mean the acid is unusable, though it signals some loss of strength as nitrogen oxides evolve. Keeping the container sealed, cool, and out of sunlight greatly slows this process.

• Store in the dark and away from heat to minimize decomposition.
• Keep containers tightly closed to retain concentration.
• Verify strength by titration before any process that depends on an exact percentage.

Rotate stock first-in, first-out and reseal promptly after each use to preserve titer and limit nitrogen-oxide buildup.

Nitric acid 20% is corrosive and oxidizing, requiring chemical splash goggles, a face shield, acid-resistant gloves such as nitrile or neoprene, and protective clothing at all times. Contact causes severe burns and characteristic yellow staining of skin, and the vapors and any nitrogen oxides are highly irritating to the lungs.

Work only with good ventilation or under local exhaust. When diluting, always add acid slowly to water, never water to acid, and keep an eyewash station and safety shower within immediate reach.

• Keep nitric acid away from organics, solvents, and combustibles; as an oxidizer it can ignite or react violently with them.
• Do not mix with bases or reducing agents without controlling the reaction.
• Neutralize small spills cautiously with soda ash or lime, then absorb the residue.

It is classified as DOT Class 8, UN 2031. Always consult the SDS before handling.

Dispose of nitric acid only in accordance with federal, state, and local regulations, never by pouring it to a drain or onto the ground. Spent or waste nitric acid typically meets the RCRA corrosivity characteristic (waste code D002) and may carry additional codes from dissolved metals picked up during use, so it must be managed as hazardous waste.

Small volumes can sometimes be carefully neutralized toward a neutral pH with a mild base such as soda ash or lime, but only within your facility's permitted procedures and discharge limits. Metal-laden waste often cannot be drain-disposed even after neutralization and should go to a licensed hazardous-waste contractor.

• Transport follows DOT Class 8, UN 2031 for dilute nitric acid.
• Keep the SDS and manifest records with the shipment.
• Confirm local discharge limits and metals restrictions before any neutralization.

The product ships as fully compliant DOT hazmat ground freight from Taylor, TX.