| (19) |
 |
|
(11) |
EP 0 104 012 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
21.08.1985 Bulletin 1985/34 |
| (43) |
Date of publication A2: |
|
28.03.1984 Bulletin 1984/13 |
| (22) |
Date of filing: 26.08.1983 |
|
|
| (84) |
Designated Contracting States: |
|
DE FR GB IT NL |
| (30) |
Priority: |
21.09.1982 US 420998
|
| (71) |
Applicant: HALLIBURTON COMPANY |
|
() |
|
| (72) |
Inventors: |
|
- Lawson, Michael Beau
()
- Martin, Larry Dale
()
|
|
| |
|
| (54) |
Composition and method for simultaneously removing iron and copper scales from ferrous
metal surfaces |
(57) Compositions for simultaeously removing iron and copper scales from ferrous metal
surfaces comprise water, one or more organic chelating acids which dissolve iron,
one or more reducing agents selected from erythorbic acid, alkali metal salts of erythorbic
acid, and ammonium salts of erythorbic acid, and, as copper complexing compound, thiourea
and/or hexahydropyrimidine-2-thione. The compositions are utilized by contacting scale-containing
ferrous metal surfaces therewith at temperatures of from about 75°F (24°C) to about
150°F (66°C).