Tungstate based corrosion inhibitors
AssigneeNalco Company
InventorsCraig W. Myers, Steven R. Hatch, Donald A. Johnson
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Abstract
A trace amount of a tungstate is disclosed for inhibiting corrosion by nitrogen fertilizer solution, in particular, an ammonium nitrate fertilizer solution, (UAN) in contact with ferrous metal storage tanks, piping, and equipment surfaces. Tungstate added with a dispersant polymer is also effective for inhibiting corrosion.
Claims18
A method for inhibiting corrosion of a ferrous metal surface exposed to a nitrogen fertilizer solution, the method comprising:
- adding an effective amount of an alkali metal tungstate and an effective amount of an iron stabilizer to said nitrogen fertilizer solution;
- optionally adding an effective amount of ortho-phosphate;
- and/or optionally adding an effective amount of phosphorilte.
A method for inhibiting corrosion of a ferrous metal surface exposed to a nitrogen fertilizer solution, the method comprising:
- adding an effective amount of an alkali metal tungstate to said nitrogen fertilizer solution;
- optionally and an effective amount of an iron stabilizer;
- optionally adding an effective amount of ortho-phosphate;
- and/or optionally adding an effective amount of phosphonite.
A method for inhibiting corrosion of a ferrous metal surface exposed to a nitrogen fertilizer solution, the method comprising;
- adding to said nitrogen fertilizer solution an effective amount of an alkali metal tungstate and effective amount of an iron stabilizer, the iron stabilizer being a dispersant polymer including an acrylic acid/acrylamide/acrylamido methane sulfonic acid terpolymer and/or a 3:1 ratio of acrylamide to acrylic acid copolymer;
- optionally adding an effective amount of orthophosphate;
- and/or optionally adding an effective amount of phosphonite.
Dependencies are inferred from the claim text.