Claims
- 1. An apparatus for tapping a molten metal bath from a reactor, comprising:
- a) a tapping pipe, having a tapping pipe inlet and a tapping pipe outlet, said tapping pipe being attachable at said tapping pipe inlet to the reactor and said tapping pipe including a susceptor, whereby said tapping pipe can be heated by an induction current to a higher temperature than that of a solidified bath metal component within said tapping pipe;
- b) an induction means at the tapping pipe, wherein said induction means can apply an induction current to the susceptor to heat the tapping pipe to a temperature that is higher than that of said bath metal within said tapping pipe and thereby melt said solidified bath metal to tap the molten metal bath from the reactor; and
- c) a ceramic insert that lines the tapping pipe to substantially prevent contact of the tapping pipe by the metal melt being tapped through said tapping pipe.
- 2. The apparatus of claim 1 wherein said susceptor component of the tapping pipe includes graphite.
- 3. The apparatus of claim 2 wherein said susceptor component further includes aluminum oxide.
- 4. The apparatus of claim 2 wherein said susceptor component further includes zirconium oxide.
- 5. The apparatus of claim 1 wherein said susceptor component of the tapping pipe has an electrical resistivity of greater than about 1.0 m.OMEGA.cm.
- 6. The apparatus of claim 1 wherein the induction means includes an induction coil assembly annularly disposed about the tapping pipe.
- 7. The apparatus of claim 6 wherein the induction coil assembly is embedded in a refractory layer.
- 8. The apparatus of claim 7 wherein the refractory layer has a thickness of at least about 15 mm.
- 9. The apparatus of claim 8 wherein the refractory material has a porosity of less than about 25%, by weight.
- 10. The apparatus of claim 9 wherein the refractory material has a thermal conductivity greater than about 2.5 W/Mk at about 25.degree. C.
- 11. The apparatus of claim 6 wherein at least about 60% of the tapping pipe is covered by said induction coil.
- 12. The apparatus of claim 6 wherein the said tapping pipe outlet extends less than about 120 mm beyond the induction coil.
- 13. The apparatus of claim 12 wherein the said tapping pipe outlet extends less than about 50 mm beyond the induction coil.
- 14. The apparatus of claim 13 wherein the said tapping pipe outlet extends less than about 20 mm beyond the induction coil.
- 15. The apparatus of claim 14 wherein the tapping pipe, outlet does not extend beyond the induction coil.
- 16. The apparatus of claim 2 further including a copper shield that extends about said induction coil.
- 17. The apparatus of claim 1 wherein said ceramic insert includes aluminum oxide and silicon carbide.
- 18. The apparatus of claim 1 wherein said tapping pipe is attached at a bottom portion of said reactor.
- 19. The apparatus of claim 1 wherein said tapping pipe is attached at a side wall of said reactor.
- 20. The apparatus of claim 1 further including controlling means at said induction means for remote control of the temperature of the tapping pipe.
- 21. The apparatus of claim 1 further including a slidable gate valve assembly at said tapping pipe outlet.
- 22. The apparatus of claim 21 wherein said slidable gate valve assembly includes a stationary plate that is in a fixed position at the tapping pipe outlet, and a slidable plate at said stationary plate which can slide between a first position that can block a path of flow of molten metal from tapping pipe outlet, and a second position that does not block said flow.
- 23. The apparatus of claim 22 further including a lubricant between said stationary plate and said slidable plate.
- 24. The apparatus of claim 22 wherein at least one of said stationary plate and said slidable plate includes a thermal insulating material.
- 25. The apparatus of claim 24 wherein the thermal conductivity of said stationary plate and of said moving plate does not exceed about 1.0 W/Mk at a temperature of about 1,400.degree. C.
- 26. The apparatus of claim 24 wherein the thermal conductivity of said stationary plate and of said moving plate does not exceed about 1.0 W/Mk at a temperature of about 25.degree. C.
- 27. The apparatus of claim 24 wherein said thermal insulating material has a thickness greater than about 20 mm.
- 28. The apparatus of claim 24 wherein said thermal insulating material includes pyrolytic graphite, having parallel layers of the graphite oriented at a right angle to a direction of heat transfer from said molten metal within said tapping pipe.
- 29. The apparatus of claim 1 further including a cooling means at said tapping pipe.
- 30. The apparatus of claim 1 further including:
- a) a sleeve annularly disposed about said induction coil;
- b) a flange at one end of said sleeve and proximate to said tapping pipe outlet, said flange defining an orifice at said tapping pipe outlet; and
- c) at least one insert at said orifice, said insert having a melting point below that of said flange.
- 31. The apparatus of claim 30 wherein said insert includes copper or a copper alloy.
- 32. The apparatus of claim 30 wherein more than one insert is located at said orifice.
- 33. The apparatus of claim 32 wherein said inserts have successively larger diameters along a path of flow of metal melt from said tapping pipe outlet, and all of said inserts having melting points below the temperature of the tapped material and below that of said flange.
- 34. The apparatus of claim 32 wherein said inserts have successively greater thicknesses along a path of flow of metal melt from said tapping pipe outlet, and all of said inserts having melting points below the temperature of the tapped material and below that of said flange.
- 35. The apparatus of claim 30 further including an obstacle means to delay initiation of flow of metal melt from said tapping pipe outlet.
- 36. The apparatus of claim 35 wherein said obstacle means is a metal disc at said outlet of said tapping pipe, said disc having a melting point above that of said insert, above that of the tapped metal melt, and below that of said flange.
- 37. The apparatus of claim 35 wherein at least one thermal insulating layer is present between said insert and said tapping pipe outlet.
- 38. The apparatus of claim 37 wherein said thermal insulating layer includes a fibrous flexible refractory material.
- 39. The apparatus of claim 37 wherein said insulating layer defines at least one opening, whereby melt emanating from said tapping pipe outlet can contact said insert.
- 40. The apparatus of claim 1, wherein said induction means has at least two zones which are separately controllable, whereby an inductive current can be directed through one or more of said zones.
- 41. The apparatus of claim 40, wherein said induction means has at least three zones.
- 42. The apparatus of claim 1, wherein said tapping pipe is attached to said reactor in an inclined position.
- 43. The apparatus of claim 42, wherein said tapping pipe outlet includes a portion that has a cross-sectioned area greater than a portion of the tapping pipe more proximate to said induction means.
- 44. The apparatus of claim 43 further including a receptacle at said tapping pipe outlet.
- 45. The apparatus of claim 1 further including a removable plug at the tapping pipe outlet.
- 46. An apparatus for tapping a molten metal bath from a reactor, comprising:
- a) a tapping pipe, having a tapping pipe inlet and a tapping pipe outlet, said tapping pipe being attachable at said tapping pipe inlet to a reactor, and said tapping pipe including a susceptor, whereby said tapping pipe can be heated by an induction current to a higher temperature than that of a solidified bath metal within said tapping pipe;
- b) a ceramic insert that lines the tapping pipe to substantially prevent contact of the tapping pipe by metal melt being tapped through said tapping pipe;
- c) an induction means at the tapping pipe; and
- d) at least three power terminals at said induction means for connection to an alternating current power source, whereby an induction current can be applied to a variable portion of the induction means, whereby said induction means can apply an induction current to heat at least a portion of the tapping pipe to a temperature that is higher than that of said bath metal within said tapping pipe and thereby melt said solidified bath metal within said tapping pipe to tap the molten metal bath from the reactor.
- 47. An apparatus for tapping a molten metal bath from a reactor, comprising:
- a) a tapping pipe, having a tapping pipe inlet and a tapping pipe outlet, said tapping pipe being attachable at said tapping pipe inlet to a reactor, and said tapping pipe including a susceptor, whereby said tapping pipe can be heated by an induction current to a higher temperature than that of a solidified bath metal within said tapping pipe;
- b) a ceramic insert that lines the tapping pipe to substantially prevent contact of the tapping pipe by metal melt being tapped through said tapping pipe;
- c) an induction means at the tapping pipe, wherein said induction means can apply an induction current to the susceptor to heat the tapping pipe to a temperature that is higher than that of said bath metal within said tapping pipe and thereby melt said solidified bath metal to tap the molten metal bath from the reactor; and
- d) a slidable gate valve assembly at said tapping pipe outlet.
- 48. An apparatus for tapping a molten metal bath from a reactor, comprising:
- a) a tapping pipe, having a tapping pipe inlet and a tapping pipe outlet, said tapping pipe being attachable at said tapping pipe inlet to a reactor, and said tapping pipe including a susceptor, whereby said tapping pipe can be heated by an induction current to a higher temperature than that of a solidified bath metal within said tapping pipe;
- b) a ceramic insert that lines the tapping pipe to substantially prevent contact of the tapping pipe by metal melt being tapped through said tapping pipe;
- c) an induction means at the tapping pipe, wherein said induction means can apply an induction current to the susceptor to heat the tapping pipe to a temperature that is higher than that of said bath metal within said tapping pipe and thereby melt said solidified bath metal to tap the molten metal bath from the reactor;
- d) a sleeve annularly disposed about said induction coil;
- e) a flange at one end of said sleeve and proximate to said tapping pipe outlet, said flange defining an orifice at said tapping pipe outlet; and
- f) at least one insert at said orifice, said insert having a melting point below that of said flange.
- 49. An apparatus for tapping a molten metal bath from a reactor, comprising:
- a) a tapping pipe, having a tapping pipe inlet and a tapping pipe outlet, said tapping pipe being attached and at an incline extending from a reactor at said tapping pipe inlet to the reactor, and said tapping pipe including a susceptor, whereby said tapping pipe can be heated by an induction current to a higher temperature than that of a solidified bath metal within said tapping pipe;
- b) a ceramic insert that lines the tapping pipe to substantially prevent contact of the tapping pipe by metal melt being tapped through said tapping pipe; and
- c) an induction means at the tapping pipe, wherein said induction means can apply an induction current to the susceptor to heat the tapping pipe to a temperature that is higher than that of said bath metal within said tapping pipe and thereby melt said solidified bath metal to tap the molten metal bath from the reactor.
- 50. A method for tapping a molten metal bath from a reactor, comprising the steps of:
- a) applying an induction current to a susceptor of a tapping pipe, whereby said tapping pipe is heated by an induction current to a higher temperature than that of a solidified bath metal component within said tapping pipe having a ceramic insert that lines the tapping pipe to substantially prevent contact of the tapping pipe by metal melt being tapped through said tapping pipe, said solidified bath metal component melting in the tapping pipe; and
- b) tapping at least a portion of the molten metal bath from the reactor.
- 51. The method of claim 50 further including the step of cooling said tapping pipe sufficiently to cause molten metal within the tapping pipe to solidify within said tapping pipe, thereby controlling tapping of the molten bath.
RELATED APPLICATION
The present application claims priority to copending U.S. Provisional Patent Application Ser. No. 60/023,428, filed on Aug. 22, 1996, the teachings of which are herein incorporated by reference.
US Referenced Citations (12)
Foreign Referenced Citations (14)
Number |
Date |
Country |
0234572A1 |
Sep 1987 |
EPX |
0560494A1 |
Sep 1993 |
EPX |
1527380 |
Sep 1968 |
FRX |
1758451 |
Sep 1976 |
DEX |
3446260-A1 |
Jul 1986 |
DEX |
3-199318 |
Aug 1991 |
JPX |
440859 |
Feb 1936 |
GBX |
1159736 |
Jul 1969 |
GBX |
1239710 |
Jul 1971 |
GBX |
WO 9421406 |
Sep 1994 |
WOX |
WO 9504621 |
Feb 1995 |
WOX |
WO 9515827 |
Jun 1995 |
WOX |
WO 9528363 |
Oct 1995 |
WOX |
WO 9634711 |
Nov 1996 |
WOX |