Title:
METHOD FOR SURFACE-TREATING ALUMINUM MATERIAL
Document Type and Number:
Japanese Patent JP3170981
Kind Code:
B2
Abstract:
PURPOSE: To provide a method for treating hydrous gel aluminum hydroxide sludge produced in the surface treating stage for an aluminum material.
CONSTITUTION: In a surface treating method for aluminum having an etching stage and the subsequent washing stage, a soln. obtd. by mixing an etching treatment-finished soln. and a washing soln. respectively recovered in both the stages in a confluent way is hydrolyzed in the presence of crystalline aluminum hydroxide to precipitate the aluminum components in the soln. as crystalline aluminum hydroxide. The precipitated crystalline aluminum hydroxide is separated to recover, and hydrous gel aluminum hydroxide sludge formed in the surface treating stage by a part of the concentrated soln. obtd. by concentrating a part of the obtd. separated soln. is melted. The obtd. sludge melted soln. is circulated in the same hydrolysis stage, furthermore, the balance of the separated soln. obtd. from the separating stage and a part of the concentrated soln. are mixed in a confluent way, in which the NaOH concentration is regulated, and it is circulated to the etching stage.
Inventors:
Akira Morita
Yasushi Egami
Noboru Sugiyama
Yoshiro Tanaka
Yasushi Egami
Noboru Sugiyama
Yoshiro Tanaka
Application Number:
JP30523893A
Publication Date:
May 28, 2001
Filing Date:
December 06, 1993
Export Citation:
Assignee:
NIPPON LIGHT METAL COMPANY,LTD.
International Classes:
C23F1/36; C23F1/46; (IPC1-7): C23F1/46
Attorney, Agent or Firm:
Katsuo Naruse (2 outside)
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