METHOD FOR PROMOTING METALLURGICAL REACTIONS IN MOLTEN METAL

• US 3,871,872 A
• Filed: 05/30/1973
• Issued: 03/18/1975
• Est. Priority Date: 05/30/1973
• Status: Expired due to Term

• Current Assignee: Elkem Metals Company A General Partnership of New York
• Original Assignee: James H. Downing, Robert H. Kaiser
• Inventors: Downing, James H., Kaiser, Robert H.
• Primary Examiner(s): Rutledge, L. Dewayne
• Assistant Examiner(s): Andrews, M. J.
• Application Number:
  US05/365,310
• Time in Patent Office: 657 Days
• Field of Search: 75/61,93R,129 423/350,348,349 266/34A
• US Class Current: 420/578
• CPC Class Codes: C01B 33/037 Purification by zone-melting C30B13/00
• CPC Class Codes: C21C 7/076 Use of slags or fluxes as treating agents C21C7/06, C21C7/064, C21C7/068 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: F27D 27/00 Stirring devices for molten material F27D3/14 takes precedence
• CPC Class Codes: Y02P 10/20 Recycling

Abstract

Method and apparatus for promoting metallurgical reactions in molten metal employing high speed stirring.

Claims

1. A METHOD FOR REFINING MOLTEN METAL CONTAINING IMPURITIES WHICH COMPRISES I. INTRODUCING MOLTEN METAL INTO A SUBSTANTIALLY CYLINDRICALLY SHAPED VESSEL II. AGITATING THE MOLTEN METAL IN SAID VESSEL BY MEANS OF A GRAPHITE ROTATING AGITATING MEMBER SUBSTANTIALLY CENTRALLY AND AXIALLY ALIGNED WITHIN SAID VESSEL WITH THE BOTTOM PORTION OF SAID AGITATING MEMBER BEING IN THE UPPER 50 PERCENT OF THE HEIGHT OF THE METAL BATH, SAID AGITATING MEMBER BEING ROTATED AT A SPEED OF FROM ABOUT 120 TO 225 R.P.M. TO PROVIDE TURBULENT AGITATION AT LEAST AT THE SURFACE OF THE METAL BATH AND SAID AGITATING MEMBER COMPRISING A SUBSTANTIALLY CYLINDRICAL HUB PORTION HAVING FROM THREE TO EIGHT RADIAL EXTENSION,THE LENGTH OF SAID RACIAL EXTENSIONS BEING FROM ABOUT 25 TO 85 PERCENT OF THE DIAMETER OF THE HUB, THE WIDTH OF SAID RADIAL EXTENSIONS BEING ABOUT 40 TO 80 PERCENT OF THEIR LENGTH, AND THE HEIGHT OF SAID RADIAL EXTENSIONS BEING FROM ABOUT 75 TO 200 PERCENT OF THE HUB DIAMETER AND THE DIAMETER OF A CIRCLE CIRCUMSCRIBING SAID RIDIAL EXTENSIONS BEING ABOUT 25 TO 40 PERCENT OF THE DIAMETER OF SAID VESSEL CONTAINING SAID MOLTEN METAL.

2. A method in accordance with claim 1 wherein the surface of the agitating member is provided with a thin adherent coating consisting essentially of about 45 t0 70% SiO2, 10 to 35% CaO, up to 30% MgO, and up to 15% Al2O3.

3. A method in accordance with claim 1 wherein the molten metal contains at least 50 percent silicon and calcium and aluminum impurities and wherein a slag is introduced into the molten metal containing vessel, said slag consisting essentially of about 45 to 70% SiO2, 10-35% CaO, 9-30% MgO.