MXPA01004771A - Iron production method of operation in a rotary hearth furnace and improved furnace apparatus - Google Patents

Abstract

The present invention is an apparatus and method for the direct reduction of iron oxide utilizing a rotary hearth furnace to form a high purity carbon-containing iron metal button. The hearth layer may be a refractory or a vitreous hearth layer of iron oxide, carbon, and silica compounds. Additionally, coating materials may be introduced onto the refractory or vitreous hearth layer before iron oxide ore and carbon materials are added, with the coating materials preventing attack of the molten iron on the hearth layer. The coating materials may include compounds of carbon, iron oxide, silicon oxide, magnesium oxide, and/or aluminum oxide. The coating materials may be placed as a solid or slurry on the hearth layer and heated, which provides a protective layer onto which the iron oxide ores and carbon materials are placed. The iron oxide is reduced and forms molten globules of high purity iron and residual carbon, which remain separate from the hearth layer. An improved apparatus includes a cooling plate that is placed in close proximity with the refractory or vitreous hearth layer, cooling the molten globules to form iron metal buttons that are removed from the hearth layer. The improvements due to the present apparatus and method of operation provide high purity iron and carbon solid buttons, which are separate from slag particulates, and discharged without significant loss of iron product to the interior surfaces of the furnace.

Description

METHOD OF PRODUCTION OF OPERATING IRON IN A ROTATING BURNER OVEN AND IMPROVED OVEN APPLIANCE TECHNICAL FIELD OF THE INVENTION This invention relates to an apparatus and method for operating a mineral processing furnace for improved processing of iron oxide reduction. More particularly, this invention relates to the method of operation of a furnace for the production of high purity iron and to an improved furnace apparatus for iron reduction.

BACKGROUND OF THE INVENTION In 1987, Midrex received United States Patent No. 4,701,214, which described the reduction in a rotary hearth furnace and a method of operation that required less energy and a smaller melting furnace introducing reducing gases. and fuel inside the rotary hearth furnace. All important steelmaking processes require the entry of iron-bearing materials as process feedstocks. For a steelmaking method that uses a basic oxygen furnace, the iron-bearing materials are usually hot metal from blown furnace and steel scrap. A widely used iron source is a product known as Reduced Direct Iron ("DRI" or "Direct Reduced Iron") that is produced by the reduction in solid state of iron ores without the formation of liquid iron. The DRI and / or iron scrap are also used for the manufacture of steel using the electric arc furnace.

Improvements are sought within the industry for furnace modifications and improved methods of operation that provide efficient production of high purity iron with low carbon material (<5%), in which iron oxides are efficiently reduced in purified iron on a hearth surface, while the slag components are separated from the purified iron at increased temperatures. In 1998, Midrex International received United States Patent No. 5,730,775 which describes an improved method known by the trade name or brand of FASTMET, and apparatus for producing direct iron reduced from dry iron oxide and compacted carbon. which are stratified in no more than two depth layers on a rotary hearth, and are metallized by heating the compacts at temperatures of about 1316C to 1427 ° C, for a short period of time. For a general understanding of the recent technique, U.S. Patent No. 5,730,775 is incorporated herein by reference.

DESCRIPTION OF THE INVENTION In the direct reduction of iron oxide in furnaces, this invention improves the use of a rotary hearth furnace using a method to produce a high purity iron product from iron oxide feedstock containing carbon composites, including the steps of: providing a rotary hearth furnace having a hearth layer consisting of a refractory layer or a vitreous hearth layer formed by placing iron oxide, carbon, and silica compounds on the sub layer -sill; heating iron oxide, carbon, and silica compounds that form a vitreous hearth layer; placing coating materials on the hearth surface to form a coated hearth layer; feeding iron oxide material into the furnace and onto the coated hearth layer; heating the iron oxide material in the coated hearth layer; reduce the iron oxide materials on the coated hearth layer; forming liquid carbon and iron globules on the coated hearth layer, with the slag materials separated; cool the carbon and iron globules with a cooling surface, creating a solid pot criche of iron and carbon product; and discharge the iron and carbon product and the slag material from the furnace. An improved apparatus includes a rotary hearth furnace having a cooling plate which is placed in close proximity to the hearth layer or refractory surface, the cooling plate cools the iron globules to form high purity iron and low carbon crucible culotes, which are removed from the vitreous hearth layer. The improvements due to the present apparatus and method of operation are to provide iron crucible cullet of high purity and low carbon content, which are separated from the slag particles, discharging the crucible culotes from the furnace without significant loss of iron. high purity in the hearth furnace, and generating iron crucible culotes with iron content of approximately 95% or more, and carbon content of approximately 5% or less in crucible cullet discharged from iron material.

OBJECT OF THE INVENTION The main object of the present invention is to provide a method for achieving an efficient production of high purity iron having carbon concentrations of 1% to 5% at elevated temperatures in a rotary hearth furnace with component separation of scoria from the purified iron on the solera surface at high temperature. Another object of the invention is to provide a method for achieving an efficient reduction of iron oxide at elevated temperatures in a processing and reduction furnace. A further object of the invention is to provide an improved furnace apparatus for providing high purity iron and cooling the high purity iron on the hearth layer surface in order to facilitate the separation of the slag components within the furnace. The objects of the invention are solved by a method for producing reduced purified iron directly at elevated temperatures within a furnace, which includes the step of providing a rotary hearth furnace having a sub-hearth layer, and introducing air-conditioning materials. iron oxide, carbon, and silica compounds with heating of the conditioning materials to form a vitreous layer in which carbon oxide agglomerates containing carbon are placed. The step of heating the conditioning materials follows the step of reducing the carbon and the agglomerated iron oxide by heating, at a specific temperature, and reducing the iron oxide. The molten beads of purified iron are separated from the slag components on the surface of the hearth layer inside the furnace. A cooling step follows the separation step, where the purified iron pellets are cooled inside the furnace by placing a cooling apparatus in close proximity to the hearth layer, with the resulting stage of solidification of purified iron inside the furnace, and the remaining stage of discharge of the purified iron from the solidified slag-free furnace, which can be discharged separately from the furnace. The objects of the invention are also solved by an apparatus for producing direct reduced iron at elevated temperatures within a rotary hearth furnace having a non-reactive hearth surface made by the laying of iron oxide and carbon facing materials and agglomerates. on the surface of the hearth layer. The hearth layer may include a vitreous layer of silica and iron oxide compounds formed before the iron oxide and carbon agglomerates are placed on the vitreous layer or the refractory layer. The coating materials and the iron oxide and carbon agglomerates are heated to a specific temperature. The iron oxide is reduced followed by the separation into globules of purified iron from the slag components and the coating materials in the hearth layer. The purified iron is solidified by the passage of the liquid iron globules in close proximity to a cooling medium above the hearth layer, which consists of the exposure to the refrigerated apparatus placed close to the hearth layer or refractory surface. After passage of the cooling media onto the hearth layer or refractory surface, the crucible cullet of purified and solidified and low carbon content is removed from the hearth layer for accumulation outside the rotary hearth furnace separated from the hearth layers. slag particles formed inside the furnace.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects will be more readily apparent by reference to the following detailed description and the accompanying drawings, in which: Figure 1 is a top view of a rotary hearth furnace for the reduction of oxide iron and the production of cast iron globules using a hearth layer surface and a means for cooling the purified iron and the low carbon globules inside the furnace. Figure 2 is a top view of the spray introduction of the coating material onto a hearth surface, which forms a coated hearth layer, with iron oxide and carbon agglomerates placed on the coated hearth layer, specific for the present invention. Figure 3 is a top view of a solid placement of coating material on a hearth layer surface, which forms a coated hearth layer, with the iron oxide and the carbon agglomerates placed on the coated hearth layer, specific for the present invention. Figure 4 is an isometric view of a plurality of materials of; Coating sprayed on and forming a coated hearth layer surface, on which iron oxide and carbon agglomerates are placed and leveled, specific for the present invention. Figure 5 is an isometric view of a plurality of solid coating materials containing a plurality of layers placed thereon and forming a coated surface, on which the iron oxide and carbon agglomerates are placed and leveled, specific for the present invention. Figure 6 is an isometric side view of the liquid purified iron and the low carbon globules on the hearth layer surface, separated from the slag particles, specific for the present invention. Figure 7 is an isometric side view of a means for cooling the purified liquid iron and the low carbon globules, with the cooling means placed in close proximity to the hearth layer surface, specific for the present invention; and Figure 8 is an isometric view of a discharge mechanism for removing the crucible bottoms of purified iron and low carbon content from the hearth layer surface, specific for the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS With reference now to the drawings, and more particularly to Figure 1, a direct reduction furnace 10 is used to reduce iron oxide feed material. The furnace, such as a rotary hearth furnace (RHF) 10, has the dimensions of a typical hearth furnace used in the iron production industry with an active hearth width of from about lm to about 7m wide, or wider . The RHF 10 has a refractory layer surface or vitreous hearth layer surface 30 which is rotatable from a zone of feedstock 12, through approximately two or three combustion zones 14, 16, 17, a reaction zone 17 and a discharge area 18 (see Figure 1). The refractory layer surface or vitreous hearth surface 30 is rotatably repeatable from the discharge zone 18 to the feedstock zone 12, and through the zones 12, 14, 16, 17, 18 for continuous operation . Each of the combustion zones 14, 16, 17 are burned by a plurality of air / fuel burners 20, 22, burned by fuel, burned by coal, or enriched with oxygen. The zone of feed material 12 includes an opening 24 and a feeding mechanism 26 by which the iron oxide and the carbon agglomerates 28, also called "green balls", are charged. An initial layer of iron oxide, carbon materials, and silica (silica oxide) can be placed in the refractory sub-hearth to form a vitreous layer 30, on which the iron oxide 28 aggregates are placed. of coating 36 placed on the surface of refractory layer or surface of vitreous hearth layer 30 may include iron oxide compounds, silica compounds, and carbon compounds. The materials can be placed by spray nozzle 32, or by solid material conveyor 34. The agglomerates 28 are leveled to a preferred height above the refractory surface or hearth layer surface 30 by a leveler 29 that covers the width of the surface 30. The agglomerates 28 are continuously fed to the RHF 10 by the feed mechanism 26, as the surface 30 is rotated about the RHF 10, by a variable speed drive (not shown). Therefore, the retention time of the iron agglomerate within the RHF 10, and within each zone 14, 16, 18, is controlled by adjusting the variable speed drive. In the area of the feed material zone 12, and upstream of the feed mechanism 26 from the feed hopper 27 for agglomerates 28, a means for introducing 32, 34 coating materials 36, such as coal dust, is located, silica, iron oxide, graphite, and refined compounds generated from raw iron oxide materials. At least one solid material conveyor 34 (FIG. 3) can introduce these coating materials 36, and additional coating compounds 38 into a separate layer on the surface of refractory layer or vitreous floor area 30. If the materials 36, 38 are fine particles, the materials 36, 38 can be mixed with a liquid carrier and applied by a spray nozzle 32. The injector 32 can be internally cooled to allow the introduction of the coating materials as fine particles in a liquid spray for application on the surface 30 (figure 2.} .. If the materials 36, 38 are placed on the RHF 10 without the liquid carrier, the conveyor 34 places the coating materials 36, and the additional coating materials 38 are close to, and through the width of the refractory layer or vitreous hearth layer 30 (Figure 3). iron oxide mixtures, silica compounds, and carbon compounds. The additional coating compounds 38 can include any of the following compounds: iron, silica, magnesium oxide (MgO), aluminum oxide (A1203), and silicon oxide (SiO2), particles generated from smelting and reduction of iron oxides, and carbonaceous materials. The coating materials 36, and the compounds 38 can have a variable material size of less than 10 mm, or preferably of about 1 mm, or less. The bulk density of the coating materials 36, 38 may be about 0.5 g / cm 3, or greater. The thickness of the coating materials 36, 38 may be about 0.1 mm or greater. The refractory layer surface or vitreous hearth surface of the RHF, with the coating materials 36 and the compounds 38 introduced on the surface 30, can be heat treated at hearth temperatures of about 1500C to about 1600C. The preferred temperature of the hearth is from about 1530C to about 1550C. After rotation through the heating zones 14, 16, the materials 36, 38 are cooled. The cooling device can be a plate 48 having internally flowing cooling liquid, with the plate 48 positioned in front of the discharge zone 18. The plate 48 is in close proximity and covering the width 30, to provide a temperature zone cooler near the surface 30. The preferred combustion temperature in zone 17 (see Figure 1) is from about 1450C to about 1600C. The iron oxide and carbon 28 agglomerates can be maintained at a temperature range of about 14OOC to about 1500C. The preferred temperature for maintaining the iron oxide agglomerates 28 is from about 1410C to about 1480C. The means for heating the surface 30, and the coating materials 36, and additional compounds 38 thereon, may include either fuel burners or other devices for heating an RHF 10, located in the furnace enclosure of the zones of the furnaces. burners 14, 16 or 17. Burner fuel includes fuel blends commonly used in the iron processing industry, such as coke oven gas, natural gas, fuel oil, and / or pulverized coal burned with air or air enriched with oxygen. After the coating materials 36 and / or the coating compounds 38 are introduced into the surface 30, the placement of iron oxide and carbon agglomerates 28 and carbon on the upper layers of the surface 30, 36, 38 it produces by the means for placing iron oxide and carbon agglomerates 28 and other feed materials by the feed mechanism 26, or other standard intermittent or continuous tape, or spiral conveyor of agglomerate size materials (Figure 1). The iron oxide and the carbon agglomerates 28 are heated and moved from the first zone 14, to a second zone 16, or a third zone if needed (not shown), on the rotating layer 30. The reduction of the agglomerates of iron oxide 28 is produced in combustion zones 14, 16 and 17, the formation of molten iron globules and the solidification of the globules occurs in a reaction zone which also has a cooling device 48, at temperatures as is specified above. During the reduction phase, the coating materials 36, 38 reduce the attack of the hearth layer 30. The coating compounds 38 provide a highly reactive and purified liquid iron barrier released by the 28 iron oxide agglomerates, forcing the liquid iron to remain in the coated layer of the hearth layer 30. The optimum intermediate phase of molten metal that is created in the operating method of an RHF is the formation of liquid globules 41 of molten metal and iron carbon having approximately 95% iron and approximately 5% carbon in solution. The preferred intermediate phase of molten metal and iron carbon is approximately 95, 5% to 97.5% of iron and about 2.5% to 4.5% of carbon in liquid globules 41 in the hearth surface 30. A specific advantage of the coating compounds 38 introduced on the surface 30, includes the creation of physically separated liquid iron / carbon 41 globules, formed as the iron oxide and carbon 28 agglomerates are reduced, melted and separated into iron / carbon 41 globules and in separate gangue and slag regimes (not shown). The iron / carbon 41 globules are formed inside the agglomerates 28 or outside the agglomerates on the hearth layer surface 30, and form molten purified iron / carbon globules 41 within combustion zones 14, 16 and / or the reaction zone 17. The iron / carbon fused beads 41 remain isolated from the gangue and slag regimes on the hearth layer surface 30, and the beads 41 are not absorbed within the hearth layer surface. 30 due to the previous coating of the surface 30. Therefore, the solidified crucible cullet 42 of highly purified solid iron product (greater than 95% iron), can be recovered from the discharge zone 18, without contamination by other particles of gangue or slag materials on the surface of; hearth 30, or on other interior surfaces of the RHF 10. The material-coated layer 36, and the coating compounds 38 can be regenerated by the periodic or continuous introduction of additional coating materials 36, 38 during the processing cycles of the RHF 10 when the cast iron crucible culotes 42 are unloaded, and before the iron oxide and the carbon agglomerates 28 are placed on the hearth layer surface 30. The iron material purified and reduced in the form of crucible culotes iron 42 containing low concentrations of carbon is removed from the discharge zone 18 by a means for removing materials from a rotating surface by a standard discharge mechanism, such as a discharge conveyor 50, such as a continuous or intermittent belt, screw, or spiral conveyor, located above the surface 30 (figure 8). The crucible culotes of purified iron 42, after separation by cooling of the residual slag, are of a higher purity and a higher carbon content than that produced by previous hearth furnace technologies such as FASTMET.

ALTERNATIVE EMBODIMENTS In an alternative operation of the RHF 10, a layer of vitreous iron oxide and silica 36, and a layer of conditioning material 38 may have been previously formed as a hearth layer 30. The iron oxide hearth layer vitreous and silica 30 helps to inhibit the attack of iron globules 41 on the hearth layer.

In an alternative embodiment, the coating materials 38, such as iron oxide, silica, magnesium oxide (MgO), aluminum oxide (A1203), and silicon oxide (SiO2), coal dust, and particles of carbon generated from the reduction and melting of iron oxides can be added to the surface 30. After rotation through the heating zones 14, 16, 17, the coating compounds 38 are cooled. The cooling device may be a plate 48 having internally flowing cooling liquid, with the plate 48 positioned in front of the discharge area 18. The plate 48 is in close proximity and covering the width of the surface of the hearth 30, in order to provide a zone of cooler temperatures near the surface of the hearth layer. In another alternative embodiment, the carbonaceous coating material 38 can be placed on the surface of the hearth layer 30 to form a separate carbon layer (not shown). The carbonaceous material 38 serves as a non-reactive sacrificial carbon layer that promotes the formation of molten iron globules 41 (see Figure 6), and of solidified iron crucible culotes 42 without the 41 globules or crucible culotes 42 attack the hearth layer 30. By keeping the globules 41 or the crucible culotes 42 separated from the slag particles and the hearth layer 30, high purity iron with a content of about 95%, and residual carbon of about 5%, can be produced. %. From the foregoing, it is readily apparent that an apparatus and method of operation have been invented to efficiently produce increased volumes and a higher purity of low carbon solid iron product from rotary hearth furnaces without significant increases in costs; processing time, or excessive oven temperatures. The invention achieves a significantly higher quality of purified and low-carbon solid iron product by adding the specified coating materials to form either a protective hearth layer of iron oxide, silica, aluminum, MgO or silicate compounds. , and / or carbon compounds on the hearth layer surface 30. The layers of materials of various compositions 36, 38 are formed by adding the coating materials before adding the iron oxide and the carbon agglomerates on the hearth surface. revolving refractory 30 (see figure 7). The improvements observed due to the described invention are due to the conditions in which, at normal furnace temperatures, the coating materials can form a protective layer 38 fixed in or on a vitreous or refractory layer 30, thereby preventing the Low-carbon, purified solid iron product covers the surface of the refractory layer or of the glass-floor hearth layer 30. A coating or adhesion condition of this type makes it difficult to remove or discharge the purified solid iron product and low carbon content outside the oven. The present invention, as claimed below, solves this problem of loss of purified iron product and low carbon content within the RHF 10. The invention has been described in detail, with reference to certain preferred embodiments, to allow the reader practicing the invention without undue experimentation. It is to be understood that the foregoing description and specific embodiments are merely illustrative of modes of the invention and the principles thereof and that various modifications and additions to the apparatus can be made by persons skilled in the art, without departing from the spirit and scope. of this invention.

Claims (34)

1. A method for producing a solid iron and carbon product from iron oxide material containing carbon compounds, characterized in that it comprises the steps of: (a) providing a rotary hearth furnace, having a hearth layer surface; (b) feeding iron oxide and carbon materials onto said hearth layer surface; (c) heating said iron oxide and carbon materials; (d) reducing said iron oxide and carbon materials; (e) forming liquid iron and carbon globules and slag particles on said hearth layer surface, said globules separating said slag particles; (f) cooling said liquid iron and carbon globules with a cooling surface, creating crucible steeps of solid iron and carbon; (g) unloading the solid iron and carbon crucible cullet from said furnace; and (h) removing the slag particles from said furnace.

2. A method according to claim 1, characterized in that said step of providing a rotary hearth furnace further comprises applying iron oxide, carbon, and silica compounds to said hearth layer surface, forming a glass layer on said layer surface of solera.

3. A method according to claim 1, characterized in that said step of providing a rotary hearth furnace further comprises introducing materials of; coating on said hearth layer surface, said coating materials being selected from the group consisting essentially of magnesium oxide compounds, silicon oxide compounds, aluminum oxide compounds, iron oxide compounds, and carbon compounds.

A method according to any of claims 1 to 3, characterized in that said heating step further comprises heating said iron oxide and carbon materials with a plurality of radiant heat sources at temperatures of at least 1450C to about 1600C inside of said oven.

A method according to any of claims 1 to 4, characterized in that said reduction step further comprises reducing said iron oxide and carbon materials with a plurality of radiant heat sources at temperatures of at least 1450C to about 154OC within of said oven.

A method according to any of claims 1 to 5, characterized in that said reduction step further comprises heating said materials with a plurality of radiant heat sources at temperatures of at least 1400C to about 1500C in said hearth layer surface .

A method according to any of claims 1 to 6, characterized in that said reduction step further comprises heating said iron oxide and carbon materials with a plurality of radiant heat sources at temperatures of at least 1410C to about 1480C in said hearth layer surface.

8. A method according to any of claims 2 to 7, characterized in that said feeding step further comprises introducing said iron oxide and carbon materials onto said vitreous layer having iron oxide, carbon, and silica compounds. .

A method according to any of claims 1 to 8, characterized in that said cooling step further comprises providing a surface of; cooling near said hearth layer surface, said surface cooling said liquid iron and carbon globules, creating a solid crucible cap of iron and carbon on said hearth surface prior to said discharge stage.

10. An apparatus for direct reduction of iron oxide material to a solid iron and carbon product, characterized in that it comprises: (a) an oven, said furnace having an inner hearth layer of refractory material; (b) means for introducing a mixture of coating materials onto said hearth layer; (c) means for placing iron oxide and carbon materials on said hearth layer or said refractory layer; (d) means for heating said hearth layer, said materials; coating, and said iron oxide and carbon materials; (e) means for reducing said iron oxide and carbon materials with the formation of liquid iron and carbon globules and slag particles, said globules separating said slag particles; (f) means for cooling said liquid iron and carbon globules on said hearth layer with the formation of a solid iron and carbon crucible cullet; (g) means for removing said crucible bottom of solid iron and carbon from said furnace; and (h) means for removing said slag particles from said furnace.

The apparatus according to claim 10, characterized in that the furnace is a rotary hearth furnace having a rotary hearth surface.

The apparatus according to claim 11, characterized in that said hearth layer of refractory material additionally comprises a vitreous layer of iron oxide and silica compounds, said glass layer being placed on said layer of refractory material before said means of introduction introduce said coating materials on said hearth layer.

The apparatus according to any of claims 10 to 12, characterized in that said means for introducing said mixture of coating material comprises a particle movement conveyor, said conveyor having the capacity to introduce said coating material onto said layer of material. sill.

The apparatus according to any of claims 10 to 13, characterized in that said mixture of coating materials comprises a material selected from the group consisting essentially of iron oxide compounds, silicate compounds, magnesium oxide compounds, compounds of silicon oxide, aluminum oxide compounds, and carbon compounds.

The apparatus according to claim 13 or 14, characterized in that said mixture of coating materials additionally comprises another layer of carbonaceous material, said carbonaceous material and said mixture of coating material being introduced by said introduction means into said layer. of solera.

16. The apparatus according to claim 13 or 14, characterized in that said mixture of coating material further comprises a carbonaceous material, said carbonaceous material being introduced by said introducing means onto said hearth layer before said materials are placed thereon. iron and carbon oxide on said hearth layer.

The apparatus according to any of claims 10 to 16, characterized in that said means for placing said iron oxide and carbon materials comprise a conveyor, wherein said iron oxide and carbon materials can be placed by said conveyor on said Solera layer.

The apparatus according to any of claims 10 to 17, characterized in that said means for heating comprises a plurality of radiant heat sources that provide heat in a temperature range of at least 1450C to approximately 1600C, maintaining said heat sources radiant said hearth layer within said temperature range.

The apparatus according to any of claims 10 to 17, characterized in that said heating means further comprises a plurality of radiant heat sources which provide heat in a temperature range of at least 1400C to about 1600C in said hearth layer inside said oven.

20. The apparatus according to any of claims 10 to 17, characterized in that said heating means further comprises a plurality of sources of; radiant heat at temperatures of at least 1450C to about 153OC in said hearth layer within said furnace.

The apparatus according to any of claims 10 to 20, characterized in that said means for cooling said liquid iron and carbon globules on said hearth layer additionally comprises a cooling surface in close proximity to said surface of said hearth.; hearth layer, said cooling surface including a cooling plate extended on said hearth layer.

The apparatus according to any of claims 10 to 21, characterized in that said means for removing the solid iron and carbon crucible culotes comprises a discharge mechanism, said unloading mechanism including a conveyor for accepting said crucible culotes solid and carbon iron from said furnace.

23. A method for producing a product of solid iron and carbon from iron oxide material containing carbon compounds, characterized in that it comprises the steps of: (a) providing an oven, said furnace providing a surface of sub layer - solera; (b) introducing conditioning materials including iron oxide compounds, carbon compounds, and silica compounds onto said subsoil layer surface; (c) heating said conditioning materials, forming a vitreous layer including at least iron oxide and silica compounds; (d) placing iron oxide and carbon materials on said vitreous layer; (e) reducing said iron oxide and carbon materials by heating; (f) forming globules of liquid iron and carbon and particles of; slag on said vitreous layer, with separation of said slag particles on said vitreous layer; (g) cooling said globules of liquid iron and carbon, forming culotes of solid iron crucible and carbon on; said vitreous layer; (h) discharging said solid iron and carbon crucible cullet from said furnace; and (i) removing said slag particles from said furnace.

24. A method according to claim 23, characterized in that said step of providing further comprises providing a ry hearth furnace having a ry hearth surface.

25. A method according to claim 23 or 24, characterized in that said step of introducing conditioning materials further comprises providing additional conditioning materials selected from the group consisting essentially of magnesium oxide compounds, silicon oxide compounds, aluminum oxide, iron oxide compounds, and carbonaceous compounds.

26. A method according to any of claims 23 to 25, characterized in that said heating step further comprises heating said coating materials with a plurality of radiant heat sources that provide heat in a temperature range of at least 1450C to about 1600C.

27. A method according to any of claims 23 to 26, characterized in that said reduction step further comprises exposing said iron oxide and carbon materials to a plurality of radiant heat sources that provide heat in a temperature range of minus 1410C to about 1480C inside said furnace.

28. A method according to any of claims 23 to 27, characterized in that said step of cooling said liquid iron and carbon globules further comprises providing a cooling surface near said vitreous layer, said cooling stage cooling said globules of liquid iron and carbon, creating solid pot crucibles of iron and carbon on said glass layer.

29. A method for producing an iron product from iron oxide material containing carbon compounds, characterized in that it comprises the steps of: (a) providing a furnace, said furnace providing a sub-hearth layer surface; (b) introducing iron oxide compounds, carbon compounds, and silica compounds onto said subsoil layer surface; (c) heating said compounds, forming a vitreous hearth layer that includes at least iron oxide and silica compounds; (d) placing coating materials on said vitreous hearth layer, forming a coated vitreous hearth layer; (e) placing said iron oxide and carbon materials on said coated vitreous hearth layer; (f) reducing said iron oxide and carbon materials on said coated vitreous hearth layer; (g) forming liquid iron and carbon globules, and slag particles on said coated vitreous hearth layer; (h) cooling said liquid iron and carbon globules, forming crucible steeps of solid iron and carbon on said coated vitreous hearth layer separated from said slag particles; (i) unloading said solid iron and carbon crucible cullet from said furnace; and (j) removing said slag particles from said furnace.

30. A method according to claim 29, characterized in that said step of providing further comprises providing a ry hearth furnace having a ry hearth surface.

31. A method according to claim 29 or 30, characterized in that said step of placing coating materials further comprises selecting said coating materials from the group consisting essentially of magnesium oxide compounds, silica oxide compounds, aluminum oxide compounds, carbonaceous compounds, and oxide compounds. of iron.

32. A method according to any of claims 29 to 31, characterized in that said heating step further comprises heating said compounds with a plurality of radiant heat sources that provide heat in a temperature range of at least 1450C to about 1600C.

33. A method according to any of claims 29 to 32, characterized in that said reduction step further comprises exposing said iron oxide and carbon materials to a plurality of radiant heat sources which provide heat in a temperature range of at least 1410C. up to about 1480 ° C inside said furnace.

34. A method according to any of claims 29 to 33, characterized in that said cooling step of said liquid iron and carbon globules further comprises providing a surface near the glass hearth surface, said surface cooling said liquid iron globules. and carbon, creating crucible culotes de; solid iron and carbon on said vitreous hearth layer coated before said discharge step. SUMMARY OF THE INVENTION The present invention is an apparatus and method for the direct reduction of iron oxide using a rotary hearth furnace to form a high purity iron-containing crucible cap containing carbon. The hearth layer may be a refractory layer or a vitreous hearth layer of iron oxide, carbon and silica compounds. Additionally, the coating materials can be introduced onto the refractory or vitreous hearth layer before iron and carbon oxide mineral materials are added, with the coating materials preventing the attack of the molten iron on the hearth layer. The coating materials may include carbon compounds, iron oxide, silicon oxide, magnesium oxide, and / or aluminum oxide. The coating materials can be placed as a solid or suspension on the hearth layer and heated, which provides a protective layer on which the iron oxide and carbon mineral materials are placed. The iron oxide is reduced and forms molten globules of high purity iron and residual carbon, which remain separated from the hearth layer. An improved apparatus includes a cooling plate that is placed in close proximity to the refractory or vitreous hearth layer, cooling the molten beads to form iron crucible culotes that are removed from the hearth layer. Improvements due to the present apparatus and method of operation provide high purity solid iron crucible stands and carbon, which are separated from the slag particles, and are discharged without significant loss of iron product to the interior surfaces of the furnace.