Method for reclaiming galvanizing quality zinc alloy from continuous galvanizing line top dross

• US 4,221,591 A
• Filed: 02/22/1979
• Issued: 09/09/1980
• Est. Priority Date: 02/22/1979
• Status: Expired due to Term

• Current Assignee: Armco Steel Company LP A de Limited Partnership
• Original Assignee: Armco Inc. (Cleveland-Cliffs Steel Holding Corp.)
• Inventors: Gibson, Alan F., Hogan, John C.
• Primary Examiner(s): Andrews, M. J.
• Application Number:
  US06/014,127
• Time in Patent Office: 565 Days
• Field of Search: 266/24, 266/86, 266/10 R, 266/227, 427/433
• US Class Current: 75/655
• CPC Class Codes: C22B 19/30 from metallic residues or scraps
• CPC Class Codes: C22B 7/04 Working-up slag
• CPC Class Codes: F27D 2099/0008 Resistor heating
• CPC Class Codes: Y02P 10/20 Recycling

Abstract

Means and a method for reclaiming galvanizing quality zinc alloy from the top dross of a continuous galvanizing line. A dross furnace is provided having front, rear and side walls and a hearth sloping from the rear wall toward the front wall. The front wall is provided with one or more tap holes or a full width slot so sized as to permit the passage of molten zinc alloy therethrough while retaining the resulting sponge or slag. The dross furnace is located with its front wall overhanging the coating pot of the continuous galvanizing line. The dross furnace is maintained at a temperature of from about 460° C. to about 850° C. and is charged with the top dross from the coating pot. The top dross has a residence time in the dross furnace of up to about two hours. The reclaimed galvanizing quality zinc alloy, at yields from about 50% to about 70% based upon the top dross treated, flows directly back into the coating pot. The resulting slag or sponge is removed from the dross furnace which is recharged with top dross.

Claims

1. A method of reclaiming galvanizing quality zinc alloy from the top dross of the coating pot of a continuous galvanizing line, said method comprising the steps of providing a dross furnace having front, rear and side walls and a hearth sloping downwardly from said rear wall toward said front wall, said front wall of said dross furnace at the juncture thereof with said hearth having at least one opening therein so sized as to permit the passage of molten zinc alloy from said dross furnace therethrough while retaining within the dross furnace any spongy slag formed therein, providing means to heat said dross furnace in a controlled fashion, locating said dross furnace at the edge of said galvanizing line coating pot with said front wall thereof and said at least one opening therein overhanging said coating pot, continuously charging said dross furnace with top dross from said coating pot, maintaining said dross furnace at a temperature of from about 460°

C. to about 850°

C., causing molten zinc alloy reclaimed from said top dross to flow through said at least one opening in said dross furnace front wall directly into said coating pot, providing a residence time for said top dross within said dross furnace of up to about two hours and periodically removing from said dross furnace spongy slag formed therein.

2. The method claimed in claim 1 including the step of maintaining said dross furnace at a temperature of from about 570°

C. to about 780°

C.