METHOD OF MELTING PARTICULATE METAL CHARGE

• US 3,873,305 A
• Filed: 04/08/1974
• Issued: 03/25/1975
• Est. Priority Date: 04/08/1974
• Status: Expired due to Term

• Current Assignee: Charles E. West, Raymond J. Claxton, Russell J. Logan
• Original Assignee: Charles E. West, Raymond J. Claxton, Russell J. Logan
• Inventors: Claxton, Raymond J., Logan, Russell J., West, Charles E.
• Primary Examiner(s): Rutledge, L. Dewayne
• Assistant Examiner(s): Andrews, M. J.
• Application Number:
  US05/458,552
• Time in Patent Office: 351 Days
• Field of Search: 75/65R,68R 266/33R,33S
• US Class Current: 75/686
• CPC Class Codes: C22B 21/0092 Remelting scrap, skimmings or any secondary source aluminium
• CPC Class Codes: C22B 7/003 only remelting, e.g. of chips, borings, turnings; apparatus used therefor
• CPC Class Codes: Y02P 10/20 Recycling
• CPC Class Codes: Y10S 266/901 Scrap metal preheating or melting

Abstract

Recycled aluminum containers and other charges of aluminum or other metals comprising pieces and particles are rapidly melted by forced submergence in a moving stream or system of molten melting media. For melting aluminum the media can be molten aluminum or a molten salt. The charge is forcibly submerged by the action of a rotating wedge blade situated within a downwardly diverging conduit.

Claims

1. A METOD OF FORCIBLY SUBMERGING A METAL CHARGE IN MOLTEN MELTING MEDIA WHEREIN SAID CHARGE COMPRISES PIECES NOT CAPABLE OF SELF-SUBMERGENCE SAID METHOD COMPRISING A. CONTINUOUSLY INTRODUCING A SUPPLY OF SAID CHARGE INTO A CONDUIT OF SUBSTANTIALLY CIRCULAR CROSS SECTION HAVING A DOWNWARDLY DIVERGING PORTION AND DISCHARGING INTO A BODY OF MOLTING MEDIA;

B. CONTAINUOUSLY URGING SAID CHARGE DOWNWARDLY BY THE ACTION OF A ROTATING WEDGE BLADE SITUATED IN SAID DIVERGING PORTION OF SAID CONDUIT, SAID WEDGE BLADE HAVING AN INCLUDED ARC DESCRIBING A SECTOR NOT SUBSTANTIALLY EXCEEDING 360* AND HAVING AT LEAST ONE SUBSTANTIAL OPENING THERETHROUGH SUCH THAT SAID CHARGE PASSES THROUGH SAID OPENING

2. The method according to claim 1 wherein the metal charge comprises aluminum or aluminum alloys.

3. The method according to claim 1 wherein said charge comprises aluminous cans or can portions.

4. The method according to claim 2 wherein said melting media is molten aluminum.

5. The method according to claim 1 wherein said body of molten media is within a chamber of cross section commensurate with that of the outlet of said conduit and is continuously depleted and replenished with molten melting media to provide movement of said media within said chamber.

6. The method according to claim 1 wherein the melting media is supplied at a rate of 10 to 50 times the rate of the charge on a weight basis.

7. The method according to claim 1 wherein the walls of said conduit diverge at from to 5* from the vertical.

8. The method according to claim 1 wherein said wedge blade has an included arc describing a sector less than 360* to provide said opening therethrough.

9. The method according to claim 8 wherein said wedge blade comprises one or more blade portions and the cumulative sector of said blades does not exceed a 180* arc.

10. The method according to claim 9 wherein said sector ranges from 160* to 200* .

11. The method according to claim 9 wherein said blade comprises two or more blade portions.

12. The method according to claim 1 wherein said blade has a pitch of from 0.1 to 0.3 times the blade diameter.

13. The method according to claim 1 wherein a gap is provided between said conduit and saId blade said gap monotonically increasing downwardly along said blade.

14. The method according to claim 1 wherein said blade is rotated at a speed to provide a volumetric displacement of from about 1 1/2 to about 50 times the volumetric rate of charge introduced to the blade.

15. The method according to claim 14 wherein said rotation is between 50 and 200 rpm.

16. The method according to claim 1 wherein said melting media is molten salt.

17. The method according to claim 5 wherein the average residence time of the molten media in said chamber is 10 to 30 seconds.

18. The improvement according to claim 1 wherein said conduit includes an upwardly diverging portion situated above said downwardly diverging portion.

19. In a method of melting a charge comprising aluminum can scrap wherein a melting media is recirculated by passing from a heating zone where it is heated to a charging zone where said charge is introduced to said melting media and back to said heating zone and a stream of molten aluminum is removed commensurate with the amount of said charge, the improvement wherein said charge is immersed in said molten media by the improvement comprising:

a. continuously introducing a supply of said charge into a substantially vertical conduit of substantially circular cross section having a downwardly diverging portion and discharging into a moving body of molten media;

b. urging said charge downwardly by the action of a rotating wedge blade situated in said diverging portion of said conduit said wedge blade having an included arc describing a sector less than 360* such that said charge passes through said blade to provide a body of said charge beneath said blade, said body being downwardly pressed and continuously urged into said molten media by the wedging action of said rotating wedge blade and being continuously replenished by further supply of said charge from above said blade.

20. In the method according to claim 18 wherein said molten media is aluminum or an alloy thereof.

21. In the method according to claim 18 wherein the volumetric displacement rate of said wedge blade is from about 1 1/2 to about 50 times the volumetric rate of the supply of said charge.

22. In the method according to claim 20 wherein said body of molten media is within a chamber of cross section commensurate with that of the outlet of said conduit and is continuously depleted and replenished with molten melting media to provide movement of said media within said chamber.

23. In a method of melting a charge comprising aluminum can scrap wherein molten aluminum is recirculated by passing from a heating zone, where it is heated to a superheated condition, to a charging zone, where said charge is introduced to said molten aluminum, and back to said heating zone and a stream of molten aluminum is removed commensurate with the amount of said charge, the improvement wherein said charge is immersed in said molten aluminum by the improvement comprising:

a. continuously introducing a supply of said charge into a substantially vertical conduit of substantially circular cross section having a downwardly diverging portion and discharging into a body of molten aluminum, having a cross section commensurate with that of the discharge of said conduit;

b. continuously urging said charge downwardly by the action of a rotating wedge blade situated in said diverging portion of said conduit and rotated at a rate to effect a volumetric displacement rate equivalent to about 1 1/2 to about 50 times the volumetric charge rate said rotating wedge blade having an included arc describing a sector less than 360* such that said charge passes substantially by gravity through the zone of said blade to provide a body of said charge beneath said blade, said body being downwardly pressed and continuously urged and immersed into said molten aluminum by the wedging and pressing action oF said rotating wedge blade and continuously replenished by further supply of said charge from above said blade;

c. continuously supplying superheated molten aluminum to said molten aluminum body beneath said conduit at a rate varying from 15 to 25 times said rate of charge introduction on a weight basis, said superheated aluminum melting said charge substantially as it is immersed thereinto;

d. continuously removing said molten aluminum and melted charge from said body.

24. In a method of melting a charge comprising metal pieces in a molten melting media wherein a portion of the metal pieces is incapable of self-submergence in said melting media, the improvement wherein said charge is forcibly immersed in said molten media by the improvement comprising:

a. introducing a supply of said charge into a substantially vertical conduit of substantially circular cross section having a downwardly diverging portion and discharging into a body of superheated molten media;

b. urging said charge downwardly by the action of a rotating wedge blade situated in said diverging portion of said conduit said wedge blade having an included arc describing a sector less than 360* such that said charge passes through said blade substantially by gravity and is pressed and urged downwardly into said molten media by the wedging action of said rotating wedge blade thereby to immerse said charge in said superheated melting media body to melt said submerged charge in said media;

c. continuously removing molten melting media and melted charge from said body;

d. continuously replenishing said body of molten melting media with superheated molten melting media.