Electric arc and ladle furnaces and components

Abstract

Electric arc, and ladle, furnaces 10 have components 14 with a high-emissivity/high reflectivity layer 18 disposed on the hot face 16. The component 14 includes a water-cooled panel 40, a duct 34, roof 12 frame 38, pipes, dry delta 36, water-cooled delta 28, fourth hole elbow 32, fourth hole roof 42, side walls 26 and combinations thereof. The high-emissivity/high-reflectivity layer 18 comprises, in dry admixture, from about 5% to about 40% of an inorganic adhesive, from about 45% to about 92% of a filler, and from about 1% to about 25% of one or more emissivity agents.

Claims

1. A component for an electric arc or ladle furnace having one or more surfaces facing a hot portion of the furnace, comprising: the surfaces have a high emissivity layer, having the properties of Thermal conductivity of 1.4 W/m/K at 350° C.; Emissivity of 0.85 to 0.95 at 2000° F.; and Dielectric constant of K=3.9 at 1 HZ; wherein the component surfaces of an electric arc or ladle furnace is taken from the group consisting of surfaces of a water-cooled panel, a duct, roof frame, pipes, dry delta, water-cooled delta, fourth hole elbow, side walls, fourth hole roof, and combinations of the surfaces thereof.

2. The component of claim 1, wherein: the high emissivity/high reflectivity layer has a thickness of about 1 mils to about 3 mils (25μ to 75μ).

3. The component of claim 1, wherein: the high-emissivity/high-reflectivity layer comprises, in dry admixture, from about 5% to about 40% of an inorganic adhesive taken from the group consisting of an alkali/alkaline earth metal silicate taken from the group consisting of sodium silicate, potassium silicate, calcium silicate, and magnesium silicate; from about 45% to about 80% of a filler taken from the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, magnesium oxide, calcium oxide, and boron oxide; and from about 1% to about 25% of one or more emissivity agents taken from the group consisting of silicon hexaboride, boron carbide, silicon tetraboride, silicon carbide (powder), molybdenum disilicide, cerium oxide, tungsten disilicide, zirconium diboride, zirconium carbide, hafnium carbide, hafnium diboride, cupric chromite, and metallic oxides.

4. The component of claim 1, wherein: the emissivity agents are one or more metallic oxides taken from the group consisting of iron oxide, magnesium oxide, manganese oxide, copper chromium oxide, chromium oxide, cerium oxide, terbium oxide, and derivatives thereof.

5. The component of claim 3, wherein: the filler is a fine particle size refractory material taken from the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, magnesium oxide, calcium oxide and boron oxide.

6. The component of claim 3, wherein: the emissivity agent(s) is (are) taken from the group consisting of silicon hexaboride, boron carbide (also known as carbon tetraboride), silicon tetraboride, silicon carbide, molybdenum disilicide, tungsten disilicide, zirconium diboride, cupric chromite, and, combinations and derivatives thereof.

7. The component of claim 3, wherein: metallic oxides taken from the group consisting of iron oxides, magnesium oxides, manganese oxides, copper chromium oxides, chromium oxides, cerium oxides, terbium oxides, and combinations thereof.

8. The component of claim 3, wherein: the high-emissivity/high-reflectivity layer further comprises, in dry admixture, from about 1.5% to about 5.0% of a stabilizer taken from the group consisting of bentonite, kaolin, magnesium alumina silica clay, tabular alumina, and stabilized zirconium oxide.

9. The component of claim 6, wherein: the stabilizer is preferably bentonite.

10. An electric arc or ladle furnace, comprising: a component for an electric arc or ladle furnace having one or more hot surface substrates facing a hot portion of the furnace, wherein the hot surface substrates have a high emissivity layer, having the properties of Thermal conductivity of 1.4 W/m/K at 350° C.; Emissivity of 0.85 to 0.95 at 2000° F.; and Dielectric constant of K=3.9 at 1 HZ; wherein the component surfaces of an electric arc or ladle furnace is taken from the group consisting of surfaces of a water-cooled panel, a duct, roof frame, pipes, dry delta, water-cooled delta, fourth hole elbow, dry delta, fourth hole roof, side walls, and combinations of the surfaces thereof.

11. The component of claim 10, wherein: the high emissivity/high reflectivity layer has a thickness of about 1 mils to about 3 mils (25μ to 75μ).

12. The component of claim 10, wherein: the high emissivity/high reflectivity layer comprises, in dry admixture, from about 5% to about 40% of an inorganic adhesive taken from the group consisting of an alkali/alkaline earth metal silicate taken from the group consisting of sodium silicate, potassium silicate, calcium silicate, and magnesium silicate; from about 45% to about 80% of a filler taken from the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, magnesium oxide, calcium oxide, and boron oxide; and from about 1% to about 25% of one or more emissivity agents taken from the group consisting of silicon hexaboride, boron carbide, silicon tetraboride, silicon carbide (powder), molybdenum disilicide, cerium oxide, tungsten disilicide, zirconium diboride, cupric chromite, and metallic oxides.

13. The component of claim 10, wherein: the emissivity agents are one or more metallic oxides taken from the group consisting of iron oxide, magnesium oxide, manganese oxide, copper chromium oxide, chromium oxide, cerium oxide, terbium oxide, and derivatives thereof.

14. The component of claim 12, wherein: the high-emissivity/high-reflectivity layer composition further comprising: water forming a wet admixture having a total solids content ranges from about 40% to about 70%.

15. The component of claim 12, wherein: the filler is a fine particle size refractory material taken from the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, magnesium oxide, calcium oxide and boron oxide.

16. The component of claim 12, wherein: the emissivity agent(s) is (are) taken from the group consisting of silicon hexaboride, boron carbide (also known as carbon tetraboride), silicon tetraboride, silicon carbide, molybdenum disilicide, tungsten disilicide, zirconium diboride, cupric chromite, and, combinations and derivatives thereof.

17. The component of claim 12, wherein: metallic oxides taken from the group consisting of iron oxides, magnesium oxides, manganese oxides, copper chromium oxides, chromium oxides, cerium oxides, terbium oxides, and combinations thereof.

18. The component of claim 12, wherein: the high-emissivity/high-reflectivity layer further comprises, in dry admixture, from about 1.5% to about 5.0% of a stabilizer taken from the group consisting of bentonite, kaolin, magnesium alumina silica clay, tabular alumina, and stabilized zirconium oxide.

19. The component of claim 18, wherein: the stabilizer is preferably bentonite.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The novel features of the described embodiments are specifically set forth in the appended claims; however, embodiments relating to the structure and process of making the present invention, may best be understood with reference to the following description and accompanying drawings.

(2) FIGS. 1A-1B are top and side views respectively of a ladle furnace roof 12 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(3) FIGS. 2A-2B are top and side views respectively of a water-cooled roof 12′ with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(4) FIGS. 3A-3B are top and side views respectively of a side wall panel 40 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(5) FIGS. 4A-4B are top and side views respectively of a water-cooled delta 28 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(6) FIGS. 5A-5B are front and side views respectively of a fourth hole elbow 32 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(7) FIGS. 6A-6B are front and side views respectively of a duct 34 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(8) FIGS. 7A-7B are top and side views respectively of a dry delta 36 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(9) FIGS. 8A-8B are top and side views respectively of a typical roof 12 frame 38 (with panels 40) having a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(10) FIGS. 9A-9B are top and side views respectively of a fourth hole 42 roof 12 panel 40 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(11) FIGS. 10A-10B are top and side views respectively of a typical roof 12 panel 40 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(12) Similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(13) The coated components 14 for electric arc or ladle furnaces 10 of the present invention may comprise shell and roof 12 panels 40 including smoke-ring and cooled exhaust ducts 34. The panels 40 that are coated with the high emissivity//high reflectivity and high dielectric constant coating systems are the panels 40 that form the interior of the furnace or the exhaust duct 34, and the surfaces that are coated, are the surfaces that face the interior of the furnace or the exhaust duct 34 (hot surfaces), that is, the surfaces that are oriented to the hottest portions of the furnace and that are subject to extreme operating conditions.

(14) The water-cooled roofs 12 use either a sprayed enclosure 24, or pressurized pipes 24, to provide coolant. FIGS. 1A-1B are top and side views respectively of a ladle furnace roof 12 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design showing the pressurized pipes through which cooling water is circulated under high pressure. FIG. 1B shows the hot face 16 and cold face 20 sides. FIGS. 2A-2B are top and side views respectively of a water-cooled roof 12′ which is a water sprayed cooled, and has a high-emissivity/high-reflectivity layer 18 disposed on the hot face thereof according to an embodiment of the present design.

(15) The coating system used on the hot surface of the water-cooled panel 40 has the following properties: thermal conductivity of 1.4 W/m/K at 350° C., emissivity of 0.85 to 0.95 at 2000° F., and a dielectric constant of K=3.9 at 1 HZ.

(16) The high emissivity/high reflectivity layer 18 may be comprised, in a preferred embodiment of the invention, by a coating composition such as the one described in the U.S. Pat. No. 7,105,047 B2, the contents of which are included herein by reference in its entirety. The high emissivity/high reflectivity layer 18 used is comprised of, in dry admixture, from about 5% to about 40% of an inorganic adhesive taken from the group consisting of an alkali/alkaline earth metal silicate taken from the group consisting of sodium silicate, potassium silicate, calcium silicate, and magnesium silicate; from about 45% to about 80% of a filler taken from the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, magnesium oxide, calcium oxide, and boron oxide; and from about 1% to about 25% of one or more emissivity agents taken from the group consisting of silicon hexaboride, boron carbide, silicon tetraboride, silicon carbide (powder), molybdenum disilicide, cerium oxide, tungsten disilicide, zirconium diboride, zirconium carbide, hafnium carbide, hafnium diboride, cupric chromite, and metallic oxides.

(17) When the emissivity agents are one or more metallic oxides, they are taken from the group consisting of iron oxide, magnesium oxide, manganese oxide, copper chromium oxide, chromium oxide, cerium oxide, terbium oxide, and derivatives thereof. The filler is a fine particle size refractory material taken from the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, magnesium oxide, calcium oxide and boron oxide. The emissivity agent(s) is (are) taken from the group consisting of silicon hexaboride, boron carbide (also known as carbon tetraboride), silicon tetraboride, silicon carbide, molybdenum disilicide, tungsten disilicide, zirconium diboride, zirconium carbide, hafnium carbide, hafnium diboride, cupric chromite, and, combinations and derivatives thereof. The metallic oxides are taken from the group consisting of iron oxides, magnesium oxides, manganese oxides, copper chromium oxides, chromium oxides, cerium oxides, terbium oxides, and combinations thereof. The coating may have, in dry admixture, from about 1.5% to about 5.0% of a stabilizer taken from the group consisting of bentonite, kaolin, magnesium alumina silica clay, tabular alumina, and stabilized zirconium oxide. Bentonite is a preferred option. A surfactant may also be used.

(18) The components 14 of an electric arc or ladle furnace that may have a high emissivity/high reflectivity layer taken from the group consisting of a water-cooled panel 40, a duct 34, roof 12 frame 38, pipes, dry delta 36, water-cooled delta 28, fourth hole elbow 32, fourth hole roof 42, and combinations thereof. FIGS. 3A-3B are top and side views respectively of a side wall panel 26 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design. The side view of FIG. 3B shows the hot side 14 and the cool side 20.

(19) FIGS. 4A-4B are top and side views respectively of a water-cooled delta 28 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design. FIGS. 7A-7B are top and side views respectively of a dry delta 36 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(20) FIGS. 5A-5B are front and side views respectively of a hole elbow 32 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design. FIGS. 6A-6B are front and side views respectively of a duct 34 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(21) FIGS. 8A-8B are top and side views respectively of a typical roof 12 frame 38 (with panels 40) having a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(22) FIGS. 9A-9B are top and side views respectively of a fourth hole 42 roof 12 panel 40 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design. FIGS. 10A-10B are top and side views respectively of a typical roof 12 panel 40 with a high-emissivity/high-reflectivity layer 18 disposed thereon according to an embodiment of the present design.

(23) A method for modifying one or more hot surfaces of at least one component 14 of an electric arc or ladle furnace involves preparing the surface of the water-cooled panel 40, which may be selected from the group comprising but not limited to: cleaners to the surface, by mechanical cleaning, or grit blasting, or combinations thereof, so that a clean surface completely free of impurities, slag or any other material is obtained.

(24) The high emissivity/high reflectivity coating composition comprised of, in wet admixture, contains from about 5% to about 40% of an inorganic adhesive taken from the group consisting of an alkali/alkaline earth metal silicate taken from the group consisting of sodium silicate, potassium silicate, calcium silicate, and magnesium silicate; from about 23% to about 56% of a filler taken from the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, magnesium oxide, calcium oxide, and boron oxide; and from about 0.5% to about 16% of one or more emissivity agents taken from the group consisting of silicon hexaboride, boron carbide, silicon tetraboride, silicon carbide (powder), molybdenum disilicide, cerium oxide, tungsten disilicide, zirconium diboride, zirconium carbide, hafnium carbide, hafnium diboride, cupric chromite, and metallic oxides; and from about 18% to about 50% water. Additionally, from about 0.5% to about 2.4% of a stabilizer taken from the group consisting of bentonite, kaolin, magnesium alumina silica clay, tabular alumina, and stabilized zirconium oxide may be included in the wet admixture. Optionally, up to about 1.0% of a surfactant may be added.

(25) Applying the coating over the surface prepared in surface preparing step by spraying using pneumatic guns, vacuum deposition, an high volume low pressure spray gun, high volume low pressure spray gun, or an airless spray gun, or other “airless” systems that use a piston system to apply the material without introducing air into the process.

(26) The coating composition has the following properties: Thermal conductivity: of 1.4 W/m/K at 350° C., Emissivity of 0.85 to 0.95 at 2000° F., and a Dielectric constant of K=3.9 at 1 HZ.

(27) It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.