Liquid metal cleaner for aqueous system

DETAILED DESCRIPTION We claim: 1.
A process for removing corrosive deposits from a metal surface exposed to an aqueous system where said process comprises: contacting an effective amount of a metal cleaner to a metal surface exposed to an aqueous system where the pH of said metal cleaner is 50 to 75 and said metal cleaner comprises: (a) from about 1 to about 40 parts by weight of citric acid; (b) from about 15 to about 25 parts by weight of an alkanolamine; (c) from about 1 to about 20 parts by weight of EDTA, alkali metal salts thereof, and ammonium salts thereof, and (d) water, where said parts by weight are based upon 100 parts of metal cleaner, and whereby corrosive deposits are removed from said metal surface.
2.
The process of claim 1 where the process is carried out a temperature of 20.
degree.
C.
to 100.
degree.
C.
3.
The process of claim 1 where the metal cleaned is selected from the group consisting of iron and steel.
4.
The process of claim 3 where the corrosive deposit removed from the metal is iron oxide or rust.
5.
The process of claim 1 where the process is carried out on-line.
6.
The process of claim 1 where the process is carried out off-line.
7.
The process of claim 1 which additionally contains a sulfur-containing polymer.
8.
The process of claim 1 where the alkanolamine is triethanolamine.
9.
The process of claim 1 wherein the metal cleaner comprises: (a) from about 10 to about 20 parts by weight of a citric acid; (b) from about 15 to about 20 parts by weight of triethanolamine; (c) from about 1 to about 20 parts by weight of ethylenediaminetetraacetic acid; (d) from about 0.
5 to about 15 parts by weight of a sulfonated polymer; and (e) a surfactant.




Description:
FIELD OF THE INVENTION The invention relates to a liquid composition useful for cleaning metal surfaces immersed in an aqueous system.
The composition comprises as a mixture: a carboxylic acid; a non chelating amine; a chelating agent or alkali metal salt or ammonium salt thereof; and preferably a sulfur-containing polymer