Metal finishing Q&As since 1989

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Sulfamic acid reactions

Hello

I am a university student that I have a research about sulfamic acid reactions. I want to know the result of the reaction of sulfamic acid with :HNO₂, NO₂- & NaNO₃ and whether special conditions are necessary (heat or catalyzer ...) for them or no? I hope you help me.

sulfamic acid + HNO₂ ----?----> ?
sulfamic acid + NO₂- ----?----> ?
sulfamic acid + NaNO₃ ----?----> ?

Zohre Hosseini
- Mashad, Khorasan, Iran
2003

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sulfamic acid + HNO₂ ----?----> ?
NH₂HSO₃ + HNO₂ -> N₂ + H₂SO₄ + H₂0

sulfamic acid + NO₂- ----?----> ?
same as above - intermediate HNO₂

sulfamic acid + NaNO₃ ----?----> nothing will happen, cause NO₃ can't be reduced

Heinz Meurer
environmental controls - Oberahr, Germany
2004

Ed. note: Thanks for helping Zohre out, Heinz, although my own sense was that he wasn't so much doing research as just submitting his homework assignment so he wouldn't have to do it himself :-) -- Ted

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2005

When we strip our electroless nickel tank we have used a 3% nitric acid strip and it is suggested to do a final rinse with sulfamic acid
https://www.pfonline.com/articles/109802.html
"To prevent the effects of nitric acid contamination, it is good practice to use a final rinse of sulfamic acid in the EN tank prior to making up a new solution."

How much sulfamic acid do we need to add to the final rinse?

Thomas Brown
Plating - Colorado Springs, Colorado, USA

Ed. note: I suspect that it's not critical at all, and the author is simply suggesting that some sulphamic acid would be better than straight water; but the more you add, the more you have to dispose of. You should be able to reach the author, Brad Durkin, at Macdermid.