Claims
- 1. A composition for inhibiting corrosion of ferrous metals and alloys thereof comprising a solution of at least one alkali or alkaline-earth metal halide in water, said solution having a density equal to or less than about 16 pounds per gallon and further having corrosion inhibiting concentrations of zinc ions and thiocyanate ions, the total zinc ion concentration of said solution independently lying in the range of from about 0.05 percent by weight to about 5.0 percent by weight, and said thiocyanate ion concentration independently lying in the range of from about 0.05 percent by weight to about 1.5 percent by weight.
- 2. The composition of claim 1 wherein the solution has a density of from about 8 pounds per gallon to about 16 pounds per gallon.
- 3. The composition of claim 1 wherein the metal halide is CaCl.sub.2, CaBr.sub.2, MgCl.sub.2, MgBr.sub.2, NaCl, NaBr, KCl, KBr or mixtures thereof.
- 4. The composition of claim 3 wherein the metal halide is CaCl.sub.2.
- 5. The composition of claim 1 wherein the zinc and thiocyanate ions are provided by zinc thiocyanate.
- 6. The composition of claim 1 wherein the zinc ions and thiocyanate ions are provided by a zinc compound and a thiocyanate compound.
- 7. The composition of claim 6 wherein the zinc compound is a zinc halide.
- 8. The composition of claim 6 wherein the thiocyanate compound is ammonium thiocyanate.
- 9. The composition of claim 1 wherein said zinc ion and thiocyanate ion concentrations independently lie in the range of about 0.05 percent by weight to about 1.5 percent by weight.
- 10. A method of inhibiting corrosion of ferrous metals and alloys thereof comprising contacting a ferrous metal or alloy thereof with a solution of at least one alkali or alkaline-earth metal halide in water, said solution having a density equal to or less than about 16 pounds per gallon and further having corrosion inhibiting concentrations of zinc ions and thiocyanate ions, the total zinc ion concentration of said solution independently lying in the range of from about 0.05 percent by weight to about 5.0 percent by weight, and said thiocyanate ion concentration independently lying in the range of from about 0.05 percent by weight to about 1.5 percent by weight.
- 11. The method of claim 10 wherein said metal halide is CaCl.sub.2, CaBr.sub.2, MgCl.sub.2, MgBr.sub.2, NaCl, NaBr, KCl, KBr or mixtures thereof.
- 12. The method of claim 11 wherein said metal halide is CaCl.sub.2.
- 13. The method of claim 10 wherein said zinc ions and said thiocyanate ions are provided by zinc thiocyanate.
- 14. The method of claim 10 wherein said zinc ions and said thiocyanate ions are provided by a zinc compound and a thiocyanate compound.
- 15. The method of claim 14 wherein said zinc compound is a zinc halide.
- 16. The method of claim 14 wherein said thiocyanate compound is ammonium thiocyanate.
- 17. The method of claim 10 wherein at least a portion of the metal is at least at a temperature of about 100.degree. F. (37.8.degree. C.).
- 18. The method of claim 10 wherein said zinc ion and thiocyanate ion concentrations independently lie in the range of from about 0.05 percent by weight to about 1.5 percent by weight.
- 19. A method of inhibiting corrosion of ferrous metals and alloys thereof comprising contacting a ferrous metal or alloy thereof with an inhibiting solution, said inhibiting solution being prepared by adding zinc ions and thiocyanate ions to a substantially zinc-free brine solution of at least one alkali or alkaline-earth metal halide in water, said solution having a density of less than or equal to about 16 pounds per gallon, such that the total zinc ion concentration lies in the range of from about 0.05 percent by weight to about 5.0 percent by weight, and the total thiocyanate ion concentration lies in the range of from about 0.05 percent by weight to about 1.5 percent by weight.
- 20. The method of claim 19 wherein said substantially zinc-free brine solution comprises less than about 0.05 percent by weight of zinc.
- 21. The method of claim 19 wherein said metal halide is CaCl.sub.2, CaBr.sub.2, MgCl.sub.2, MgBr.sub.2, NaCl, NaBr, KCl, KBr or mixtures thereof.
- 22. The method of claim 21 wherein said metal halide is CaCl.sub.2.
- 23. The method of claim 19 wherien said zinc ions and said thiocyanate ions are provided by zinc thiocyanate.
- 24. The method of claim 19 wherein said zinc ions and said thiocyanate ions are provided by a zinc compound and a thiocyanate compound.
- 25. The method of claim 24 wherein said zinc compound is a zinc halide.
- 26. The method of claim 24 wherein said thiocyanate compound is ammonium thiocyanate.
- 27. The method of claim 19 wherein at least a portion of the metal is at least at a temperature of about 100.degree. F. (37.8.degree. C.).
- 28. The method of claim 19 werein said zinc ion and thiocyanate ion concentrations independently lie in the range of from about 0.05 percent by weight to about 1.5 percent by weight.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of the copending application Ser. No. 636,436, filed July 31, 1984, now abandoned.
US Referenced Citations (23)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2027686 |
Feb 1980 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Chemical Abstracts, vol. 68, 1968, p. 3169, Abstract No. 32471Z. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
636436 |
Jul 1984 |
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