Why Nitric Acid 40%
Nitric Acid 40% Technical Grade (CAS 7697-37-2) delivers a precisely balanced mid-range concentration tailored for heavy industrial, petroleum refining, and large-scale wastewater operations. Formulated as a clear, colorless liquid, this HNO3 concentration provides powerful oxidative properties while mitigating the severe fuming and extreme exothermic reactions typically associated with diluting stronger acids. Facility operators rely on the 40% solution to streamline metal surface treatments, chemical synthesis, and rapid pH reductions without incurring the higher costs associated with strict analytical certifications. Because it is completely miscible with water, alcohol, and most organic solvents, it integrates rapidly into continuous-flow processes and batch treatment tanks without causing localized pooling or stratification.
Best Applications for This Grade
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Wastewater pH Normalization: Commonly applied in heavy industrial effluent systems to rapidly neutralize strongly alkaline discharges. The 40% concentration allows operators to meter the acid accurately into large holding tanks, utilizing its complete water miscibility to ensure a uniform pH drop before environmental discharge.
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Petroleum Equipment Passivation: Acts as a robust oxidizing agent to strip tough organic residues, hydrocarbon scale, and mineral deposits from downstream processing equipment, pipelines, and storage vessels. This prepares the metal surfaces for subsequent operational phases or return to service.
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Industrial Metal Pickling: Commonly applied in metal finishing facilities to aggressively remove heavy oxide layers, scale, and surface impurities from carbon steel and custom alloys. The mid-range concentration provides rapid etching action prior to coating, electroplating, or structural welding.
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Heavy-Duty Heat Exchanger Descaling: Dissolves stubborn calcium, magnesium, and rust accumulations within industrial cooling towers and heat exchange networks. Using a pre-diluted 40% solution helps maintenance teams avoid the complex dilution mathematics and intense heat generation associated with stronger concentrations.
When to Choose a Different Grade
- If your process demands a milder acidic profile to prevent over-etching delicate substrates or requires less aggressive routine pH adjustments, select Nitric Acid 5% or Nitric Acid 20%.
- If your facility workflow requires a slightly lower mid-range concentration specifically calibrated for continuous chemical manufacturing or custom dilution sequences, consider Nitric Acid 25%.
- If your operators are performing quantitative analytical laboratory methods, trace-metal analysis, or processes requiring strict compliance with American Chemical Society standards, switch to Nitric Acid 65% ACS Grade.
- If your organization handles semiconductor manufacturing, microelectronics fabrication, or highly sensitive laboratory procedures demanding strict control over particulate contamination, specify Nitric Acid 70% ACS Grade - Low Particle.
| Molecular Weight |
63.01 |
| Formula |
HNO3 |
| Assay |
39-41% |
| Grade |
Reagent |
| Form |
Liquid |
| Solubility |
Miscible with water |
| Appearance |
Clear, colorless liquid |
| Melting Point |
-42 |
| Boiling Point |
83 |
| Specific Gravity |
1.2 |
| Industry |
Analytical Chemistry, Industrial, Electronics, Environmental, Research |