Ultrasonic degassing of molten metals

• US 8,574,336 B2
• Filed: 04/08/2011
• Issued: 11/05/2013
• Est. Priority Date: 04/09/2010
• Status: Active Grant

• Current Assignee: Southwire Company
• Original Assignee: Southwire Company
• Inventors: Rundquist, Victor F., Gill, Kevin S.
• Primary Examiner(s): Wyszomierski, George
• Assistant Examiner(s): MCGUTHRY BANKS, TIMA MICHELE
• Application Number:
  US13/082,437
• Publication Number:
  US 20110247456A1
• Time in Patent Office: 942 Days
• Field of Search: 757/09
• US Class Current: 75/10.4
• CPC Class Codes: C21C 7/072 Treatment with gases C21C7/06, C21C7/064, C21C7/068 take precedence
• CPC Class Codes: C22B 21/06 refining electrolytic refining C25C; C22B21/0046, C22B21/0061 take precedence
• CPC Class Codes: C22B 21/064 using inert or reactive gases C22B21/066 and C22B21/068 take precedence
• CPC Class Codes: C22B 9/00 General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
• CPC Class Codes: C22B 9/02 Refining by liquating, filtering, centrifuging, distilling, or supersonic wave action including acoustic waves; C22B9/003, C22B9/006, C22B9/05, C22B9/22 take precedence
• CPC Class Codes: C22B 9/026 by acoustic waves, e.g. supersonic waves
• CPC Class Codes: C22B 9/05 Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ
• CPC Class Codes: F27D 2003/166 the fluid being a treatment gas
• CPC Class Codes: F27D 2003/169 Construction of the lance, e.g. lances for injecting particles
• CPC Class Codes: F27D 3/16 Introducing a fluid jet or current into the charge porous elements for gas flushing of molten metals B22D1/005
• CPC Class Codes: Y02P 10/20 Recycling

Abstract

Ultrasonic devices having an integrated purging gas delivery system are described, and such devices can be used to remove dissolved gasses and impurities from molten metals.

Claims

1. A method for reducing an amount of a dissolved gas in a molten metal bath, the method comprising:

operating an ultrasonic device in the molten metal bath, the ultrasonic device comprising;

an ultrasonic transducer,

an elongated probe comprising a first end and a second end, the first end attached to the ultrasonic transducer and the second end comprising a tip, and

a purging gas delivery system, the purging gas delivery system comprising a purging gas inlet and a purging gas outlet,

wherein the elongated probe comprises a ceramic, and the purging gas outlet is at the tip of the elongated probe; and

introducing a purging gas into the molten metal bath through the purging gas outlet at the tip of the elongated probe.

2. The method of claim 1, wherein the dissolved gas comprises oxygen, hydrogen, sulfur dioxide, or a combination thereof.

3. The method of claim 1, wherein the molten metal bath comprises aluminum, copper, zinc, steel, magnesium, or a combination thereof.

4. The method of claim 1, wherein the purging gas comprises nitrogen, helium, neon, argon, krypton, xenon, or combinations thereof.

5. The method of claim 1, wherein the purging gas is introduced into the molten metal bath at a rate in a range from about 0.1 to about 150 L/min.

6. The method of claim 1, wherein the purging gas is introduced into the molten metal bath at a rate in a range from about 10 to about 500 mL/hr of purging gas per kg/hr of output from the molten metal bath.

7. The method of claim 1, wherein the method results in a reduction of at least about 10 weight percent in the amount of the dissolved gas in the molten metal bath.

8. The method of claim 1, wherein the method results in a reduction of alkali metal impurities in the molten metal bath.

9. The method of claim 1, wherein the dissolved gas comprises hydrogen, and wherein the method results in a reduction of the amount of hydrogen in the molten metal bath to less than about 4 ppm.

10. The method of claim 1, wherein the method is conducted in the substantial absence of chlorine gas.

11. The method of claim 1, wherein:

the purging gas is introduced into the molten metal bath at a rate in a range from about 1 to about 50 L/min;

the dissolved gas comprises hydrogen;

the molten metal bath comprises aluminum, copper, or a combination thereof; and

the purging gas comprises argon, nitrogen, or a combination thereof.

12. The method of claim 11, wherein the purging gas is introduced into the molten metal bath at a rate in a range from about 30 to about 200 mL/hr of purging gas per kg/hr of output from the molten metal bath.

13. The method of claim 1, wherein the elongated probe comprises Sialon.

14. The method of claim 1, wherein the ultrasonic device further comprises a cooling system surrounding at least a portion of the elongated probe.

15. The method of claim 14, wherein the cooling system comprises at least one channel surrounding at least a portion of the elongated probe.

16. The method of claim 15, wherein the channel comprises a fluid.

17. The method of claim 16, wherein the fluid is argon.