Samiksha Jaiswal (Editor)

Red fuming nitric acid

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Formula
  
HNO3 + NO2

Appearance
  
Liquid, Red fumes

Boiling point
  
120.5 °C

Red fuming nitric acid Larry Bond39s Red Phoenix Series AThrillAWeek

Red fuming nitric acid and its action upon miscellaneous substances including marshmallow peeps


Red fuming nitric acid (RFNA) is a storable oxidizer used as a rocket propellant. It consists of 84% nitric acid (HNO3), 13% dinitrogen tetroxide and 1–2% water. The color of red fuming nitric acid is due to the dinitrogen tetroxide, which breaks down partially to form nitrogen dioxide. The nitrogen dioxide dissolves until the liquid is saturated, and evaporates off into fumes with a suffocating odor. RFNA increases the flammability of combustible materials and is highly exothermic when reacting with water.

Contents

Red fuming nitric acid CHINAMIL NITRIC ACID AmericaSpace

It is usually used with an inhibitor (with various, sometimes secret, substances, including hydrogen fluoride; any such combination is called "inhibited RFNA" IRFNA) because nitric acid attacks most container materials.

Red fuming nitric acid Sciencemadness Discussion Board Storage of Fuming Nitric acid

It can also be a component of a monopropellant; with substances like amine nitrates dissolved in it, it can be used as the sole fuel in a rocket. It is not normally used this way however.

Red fuming nitric acid httpsiytimgcomviZoyRjcLKFxkmaxresdefaultjpg

During World War II, the German military used RFNA in some rockets. The mixtures used were called S-Stoff (96% nitric acid with 4% ferric chloride as an ignition catalyst) and SV-Stoff (94% nitric acid with 6% dinitrogen tetroxide) and nicknamed Salbei (sage).

Red fuming nitric acid Amazing Rustcom Nitric Acid

Inhibited RFNA was the oxidizer of the world's most-launched light orbital rocket, the Kosmos-3M.

Other uses for RFNA include fertilizers, dye intermediates, explosives, and pharmaceutic aid as acidifier. It can also be used as a laboratory reagent in photoengraving and metal etching.

Red fuming nitric acid V 24 metals in nitric acid Metalle in Salpetersure YouTube

Distilling red fuming nitric acid


Compositions

Red fuming nitric acid Red Fuming Nitric Acid What occurs

  • IRFNA IIIa: 83.4% HNO3, 14% NO2, 2% H2O, 0.6% HF
  • IRFNA IV HDA: 54.3% HNO3, 44% NO2, 1% H2O, 0.7% HF
  • S-Stoff: 96% HNO3, 4% FeCl3
  • SV-Stoff: 94% HNO3, 6% N2O4
  • AK20: 80% HNO3, 20% N2O4
  • AK20F: 80% HNO3, 20% N2O4, fluorine-based inhibitor
  • AK20I: 80% HNO3, 20% N2O4, iodine-based inhibitor
  • AK20K: 80% HNO3, 20% N2O4, fluorine-based inhibitor
  • AK27I: 73% HNO3, 27% N2O4, iodine-based inhibitor
  • AK27P: 73% HNO3, 27% N2O4, fluorine-based inhibitor

    • Experiments

  • Hydrofluoric acid content of RFNA

    • Red fuming nitric acid Fuming Nitric Acid vs Lab Gloves YouTube
    When RFNA is used as an oxidizer for rocket fuels, it usually has a HF content of about 0.6%. The purpose of the HF is to act as a corrosion inhibitor.
  • Water content of RFNA
    • To test the water content, a sample of 80% HNO3, 8–20% NO2, and the rest H2O depending on the varied amount of NO2 in the sample. When the RFNA contained HF, there was an average H2O% between 2.4% and 4.2%. When the RFNA did not contain HF, there was an average H2O% between 0.1% and 5.0%. When the metal impurities from corrosion were taken into account, the H2O% increased, and the H2O% was between 2.2% and 8.8%
  • Corrosion of metals in RFNA
    • Stainless steel, aluminium alloys, iron alloys, chrome plates, tin, gold and tantalum were tested to see how RFNA affected the corrosion rates of each. Experiments were performed using 16% and 6.5% RFNA samples and the different substances listed above. Many different stainless steels showed resistance to corrosion. Aluminium alloys did not hold up as well as stainless steels especially in high temperatures but the corrosion rates were not high enough to prohibit the use of this with RFNA. Tin, gold and tantalum showed high corrosion resistance similar to that of stainless steel. These materials are better though because at high temperatures the corrosion rates did not increase much. Corrosion rates at elevated temperatures increase in the presence of phosphoric acid. Sulfuric acid decreased corrosion rates.

    References

    Red fuming nitric acid Wikipedia
    (Text) CC BY-SA


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