Method for preventing the formation of white rust on a zinc-coated steel surface
AssigneeSuez Groupe
InventorsStéphanie Mourier, Eric Toledo
Life of this patent
Estimating the term…
Abstract
A process for preventing the formation of white rust on a steel surface at least partially coated with zinc includes a) bringing said surface, preferably under thermal load, into contact with an aqueous composition, the pH of which is between 6.5 and 8.5 comprising at least one organic acid of formula: R—X—OH (I) wherein X represents C(O) or S(O)2, and R represents an organic chain. A composition and also to a cooling tower treated by the process are provided.
Claims13
A process for preventing the formation of white rust on a steel surface at least partially coated with zinc, comprising a) bringing said surface at least partially coated with zinc into contact with an aqueous composition, the pH of which is between 6.5 and 8.5 and comprising at least one organic acid of formula (I):
- R—X—OH (I)
- wherein X represents S(O)2, and R represents:
- a linear or branched C1-C12 alkyl, optionally substituted with one or more groups chosen from a halogen, OH, COOH or an aryl or heteroaryl group, said aryl or heteroaryl group being itself optionally substituted with a halogen, OH, a linear or branched C1-C4 alkyl or a COOH group;
- or
- an aryl or heteroaryl group, optionally substituted with a halogen, OH, linear or branched C1-C4 alkyl or COOH group;
- b) measuring the pH of said composition brought into contact with the surface at least partially coated with zinc, and
- c) depending on the result of the measurement obtained in step b), adjusting the pH of said composition in contact with the surface at least partially coated with zinc to a value between 6.5 and 8.5 by addition of a further amount of said at least one acid of formula (I).
A process for preventing the formation of white rust on a steel surface at least partially coated with zinc, comprising a) bringing said surface at least partially coated with zinc into contact with an aqueous composition, the pH of which is between 6.5 and 8.5 and comprising at least one organic acid of formula (I):
- R—X—OH (I)
- wherein X represents S(O)2, and R represents:
- a linear or branched C1-C12 alkyl, optionally substituted with one or more groups chosen from a halogen, OH, COOH or an aryl or heteroaryl group, said aryl or heteroaryl group being itself optionally substituted with a halogen, OH, a linear or branched C1-C4 alkyl or a COOH group;
- or
- an aryl or heteroaryl group, optionally substituted with a halogen, OH, linear or branched C1-C4 alkyl or COOH group;
- b) measuring the pH of said composition brought into contact with the surface at least partially coated with zinc, and
- c) depending on the result of the measurement obtained in step b), adjusting the pH of said composition in contact with the surface at least partially coated with zinc to a value between 6.5 and 8.5 by addition of a further amount of said at least one acid of formula (I), wherein the aqueous composition further comprises hexametaphosphate.
Dependencies are inferred from the claim text.