Metal dissolution process
AssigneeDart Environment and Services Company
InventorDavid Robert Kamperman
Life of this patent
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Abstract
Evolution of NOx fumes during dissolution of metal values in mineral acid solutions of nitric acid can be eliminated by the addition of small quantities of hydrogen peroxide to the acid solution.
Claims13
A method for prevention of evolution of NOx fumes in the dissolution of metal values in mineral acid solutions containing HNO.sub.3 which comprises adding hydrogen peroxide to said acid solution, maintaining the hydrogen peroxide concentration during the dissolution at between about 1 and about 20 grams per liter and the mole ratio of hydrogen peroxide to mineral acid at a value of less than 0.273.
A process for bright dipping copper or copper alloys without evolution of NOx fumes which comprises immersing the copper or copper alloy in a bright dip acid solution containing from about 430 to about 460 grams per liter of H.sub.2 SO.sub.4, from about 100 to about 150 grams per liter of HNO.sub.3 from about 0.2 to about 3 grams per liter of HCl and from about 8 to about 12 grams per liter of hydrogen peroxide.
A bright dip solution for copper or copper alloys comprising:
- from about 430 to about 460 grams per liter of H.sub.2 SO.sub.4 ;
- from about 100 to about 150 grams per liter of HNO.sub.3 ;
- from about 0.2 to about 3 grams per liter of HCl, and
- from about 8 to about 12 grams per liter of hydrogen peroxide.
Dependencies are inferred from the claim text.