Inner surface of smelting furnace

Abstract

The present invention relates to a furnace having a roof comprising an inner surface (2). The inner surface (2) of the roof comprises at least one steel insert (1) arranged at the periphery of the inner surface (2) of the roof, the at least one steel insert creating a protrusion extending from the inner surface (2) of the roof. The present invention also relates to a cooling element for a furnace comprising at least one steel insert arranged at its periphery and to the use of the smelting furnace in a direct iron reduction process, electric smelting process, electric reduction process, flash smelting process, flash converting process, bath smelting process or bath converting process.

Description

[0001] INNER SURFACE OF SMELTING FURNACE

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a furnace having a roof comprising an inner surface , wherein the inner surface of the roof comprises at least one steel insert arranged at the periphery of the inner surface . The present invention also relates to a cooling element comprising at least one steel insert arranged at its periphery and to the use of the furnace in a direct iron reduction process , electric smelting process , electric reduction process , flash smelting process , flash converting process , bath smelting process or bath converting process .

[0004] BACKGROUND OF THE INVENTION

[0005] During operation of furnaces used in direct iron reduction processes , electric smelting processes , electric reduction processes , flash smelting processes , flash converting processes , bath smelting processes and bath converting processes , gas may be fed to the furnace and gas may also be generated in the furnace . The gas usually has a high temperature and may contain small , melted particles . This may cause abrasion on the inner surface of the furnace . Particularly the outer edges of the inner surface of the roof of the furnace are exposed to extreme temperatures . This is especially prominent in the reaction shaft of flash smelting and flash converting furnaces .

[0006] The inner surface of the roof often contains cooling elements and / or bricks . However, the bricks may wear over time due to the hot gas and small melted particles and might need to be replaced at certain intervals . Also , the cooling elements may not have enough capacity to maintain a certain temperature when the conditions become extreme .

[0007] As such, there in a need for improving the inner surface of the roof and cooling elements of furnaces and particularly in the reaction shaft .

[0008] SUMMARY

[0009] According to a first aspect , a furnace having a roof comprising an inner surface , wherein the inner surface of the roof comprises at least one steel insert arranged at the periphery of the inner surface of the roof , the at least one steel insert creating a protrusion extending from the inner surface of the roof , is provided .

[0010] According to a second aspect , a cooling element for a furnace is provided, the cooling element comprising a housing, the housing comprising channels for the flow of cooling water or refrigerants , wherein the cooling element further comprises at least one steel insert arranged at the periphery of the hot side of the housing, the at least one steel insert creating a protrusion extending from the cooling element .

[0011] According to a third aspect , a use of the furnace according to the first aspect , or a use of the cooling element according to the second aspect in a furnace , in a direct iron reduction process , electric smelting process , electric reduction process , flash smelting process , flash converting process , bath smelting process or bath converting process is provided . BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings , which are included to provide a further understanding of the invention and constitute a part of this specification, illustrate embodiments of the invention and together with the description help to explain the principles of the invention . In the drawings :

[0013] Figure 1 shows a furnace having a roof comprising an inner surface comprising steel inserts arranged at the periphery of the inner surface ;

[0014] Figure 2 shows a cross section of a roof of a reaction shaft of a furnace comprising steel inserts embedded therein and showing the transverse direction of the steel inserts ;

[0015] Figure 3 shows a reaction shaft comprising steel inserts creating a frame-like structure essentially covering the peripheries of the inner surface of the roof ; and

[0016] Figure 4 shows a cooling element comprising a steel insert arranged at the periphery of the cooling element .

[0017] DETAILED DESCRIPTION

[0018] It is obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways . The invention and its embodiments are thus not limited to the examples described below, instead they may vary within the scope of the claims . The description related to the furnace having a roof described below also apply to the cooling element described below and vice versa.

[0019] A furnace having a roof comprising an inner surface comprising at least one steel insert

[0020] According to a first aspect and as seen in figure 1, a furnace having a roof comprising an inner surface (2) , wherein the inner surface (2) of the roof comprises at least one steel insert (1) arranged at the periphery of the inner surface (2) of the roof, the at least one steel insert (1) creating a protrusion extending from the inner surface (2) of the roof, is provided .

[0021] The furnace may be a furnace for a direct iron reduction process, electric smelting process, electric reduction process, flash smelting process, flash converting process, bath smelting process or bath converting process.

[0022] The furnace may be a flash smelting or a flash converting furnace, and may comprise the following: i. a reaction shaft (3) provided with a burner (5) for burning concentrate or matte (6) and feeding concentrate or matte (6) into the reaction shaft (3) to form a jet of an at least partially oxidised suspension in the reaction shaft (3) ; ii. a settler (8) in communication with a lower end of the reaction shaft (3) , wherein the settler (8) has an inner space and a first end wall structure (16) at one end of the settler (8) and a second end wall structure (15) at the opposite end of the settler (8) and a landing zone for the jet of the at least partially oxidised suspension in the inner space of the settler (8) below the lower end of the reaction shaft (3) , and wherein the settler (8) is configured to receive the at least partially oxidised suspension from the reaction shaft (3) at the landing zone and to form a layer of matte or metal alloy (10) and a layer of slag (9) on top of the layer of matte or metal alloy (10) in the inner space of the settler (8) ; iii. a first taphole (11) for discharging slag (12) from the layer of slag (9) in the inner space of the settler (8) , and a second taphole (14) for discharging matte or metal alloy (13) from the layer of matte or metal alloy (10) in the inner space of the settler ( 8 ) ; and vi . an uptake shaft (4) for leading process gases (7) from the smelting furnace via the uptake shaft (4) , wherein the uptake shaft (4) has a lower end in communication with the settler (8) .

[0023] The term in communication with may refer to an open space being available between the discussed components such that the components share the open space, and such that material can be freely exchanged between the components .

[0024] The settler (8) may further comprise two side walls, a bottom and a roof extending between the first end wall structure (16) and second end wall structure (15) . The end wall structures (16, 15) may have the form of a square or rectangle such that the side walls, bottom and roof extend from the peripheries of the first end wall (16) to the peripheries of the second end wall (15) , and thereby form a closed space between the end walls (27,28) , bottom, roof and sidewalls. The reaction and uptake shafts (3, 4) may be located in or on the roof of the settler (8) and the layer of slag and matte or metal alloy (9, 10) may rest on the bottom when the device is in operation.

[0025] Accordingly, the bottom and the roof may extend substantially in the horizontal direction and the end walls (16, 15) as well as the side walls may extend substantially in the vertical direction when the device is placed on the surface on which it is to be used.

[0026] In this disclosure, vertical may mean the direction of gravity and horizontal may mean the direction that is perpendicular to the vertical direction.

[0027] Also in this disclosure, substantially horizontally and / or vertically may mean to a great or significant extent horizontally and / or vertically. For instance, substantially vertically / horizontally could mean a completely vertical / horizontal direction or a deviation from the vertical / horizontal direction with 2°, or 4°, or 6°, or 8°, or 10°.

[0028] The reaction and uptake shafts (3, 4) may have the shape of a cylinder, cube or cuboid, or anything therein between, such that they have a bottom, roof and one or more walls. The bottoms and roofs may extend substantially in the horizontal direction and the one or more walls may extend substantially in the vertical direction. The reaction and uptake shafts (3, 4) may be arranged in or on the roof of the settler (8) . Therefore, the reaction and uptake shafts (3, 4) may have an opening in the bottom or may lack a bottom such that the reaction and uptake shafts (3, 4) are in communication with the settler ( 8 ) . The furnace may be an electric furnace . The furnace may comprise the following : i . a roof with openings for feeding concentrate or matte in a solid and / or liquid phase , at least one electrode and means for releasing process gases from the furnace ; ii . a furnace space having at least one wall and a bottom for receiving the concentrate or matte and the at least one electrode and for forming a layer of matte or metal alloy and a layer of slag on top of the layer of matte or metal alloy in the furnace space on the bottom, the at least one wall may comprise openings for feeding concentrate or matte in a solid and / or liquid phase ; iii . a first taphole for discharging slag from the layer of slag in the furnace space , and a second taphole for discharging matte or metal alloy from the layer of matte or metal alloy in the furnace space .

[0029] The roof and bottom may be round and the wall may extend between the roof and bottom . The furnace space may thus have the shape of a cylinder . The bottom and roof may extend substantially in the hori zontal direction and the wall in the vertical direction when the furnace is placed on the surface , on which it is to be used . The layer of slag and matte or metal alloy may rest on the bottom when the device is in operation .

[0030] The furnace may be a bath smelting furnace , bath converting furnace or electric reduction furnace .

[0031] The electric furnace may be a direct iron reduction furnace .

[0032] For the avoidance of doubt , some examples of the embodiments are given in connection with a flash smelting / converting furnace throughout the specification. However, the skilled person understands that the embodiments may relate to a flash smelting / converting furnace, electric furnace, such as a direct iron reduction furnace, bath smelting furnace, bath converting furnace or electric reduction furnace, throughout the specification .

[0033] For the avoidance of doubt, the inner surface (2) of the roof may refer to the inner surface (2) of the roof of the settler (8) , the inner surface (2) of the roof of the reaction shaft (3) , the inner surface (2) of the roof of the uptake shaft (4) or the inner surface (2) of the roof of the electric arc furnace. The inner surface (2) of the roof may refer to any roof structure of the inner space of a direct iron reduction furnace, bath smelting furnace, bath converting furnace or electric reduction furnace.

[0034] The inner surface (2) of the roof may refer to the part of the roof facing the inside of the furnace.

[0035] The periphery may refer to the outer boundary or edge of a physical object or area. For example, the periphery of the inner surface (2) of the roof may refer to the part of the inner surface (2) of the roof of the settler (8) adjacent to the walls of the settler (8) , the part of the inner surface (2) of the roof of the reaction shaft (3) adjacent to the walls of the reaction shaft (3) , the part of the inner surface (2) of the roof of the uptake shaft (4) adjacent to the walls of the uptake shaft (4) and / or the part of the inner surface (2) of the roof of the electric furnace adjacent to the wall of the electric furnace. In this disclosure, a protrusion typically refers to an element or feature that extends outward from a surface or structure. It could be a raised portion, a bulge or an extension that extends beyond the general profile of the object, i.e. of the inner surface (2) of the roof of the furnace.

[0036] For the avoidance of doubt, when the inner surface (2) of the roof comprises more than one steel inserts (1) , each steel insert (1) may create a protrusion extending from the inner surface (2) of the roof.

[0037] It has been found that the peripheries of the inner surface (2) of the roof are particularly exposed to hight temperatures during operation of the furnace. The above steel insert (s) (1) have been found to give surprisingly good protection to the areas of the inner surface (2) most exposed to heat.

[0038] The steel insert (s) (1) according to the first aspect may have an elongated shape.

[0039] In this disclosure, an elongated shape may refer to a geometric form that is characterized by having one dimension significantly longer than the others.

[0040] The longitudinal direction of the steel insert (s) (1) according to the first aspect may extend substantially horizontally along the inner surface (2) of the roof.

[0041] Accordingly, the longitudinal direction of the steel insert (s) (1) may extend substantially parallel to the bottom and roofs of the furnace. In other words, the end points of the steel insert (s) (1) having an elongated shape may point substantially towards the walls of the furnace rather than towards the bottom and roof of the furnace. The steel insert (s) (1) according to the first aspect may be L-shaped in the transverse direction.

[0042] For the avoidance of doubt, the longitudinal direction may refer to the direction along the length of the elongated shape and the transverse directions may refer to the directions perpendicular to the longitudinal direction, encompassing both width and height or diameter .

[0043] An L-shape may refer to a geometric shape or object that resembles the letter "L". It may consist of two straight arms or segments that meet at a right angle, forming a close to 90-degree corner. The two arms can be of different lengths, although they can also be equal .

[0044] The steel insert (s) (1) according to the first aspect may be arranged such that a first arm of the L- shape is embedded in the roof and a second arm of the L-shape extends along the inner surface (2) of the roof.

[0045] Figure 2 is a cross section of a roof off a reaction shaft (3) of a furnace comprising steel inserts (1) and showing the transverse direction of the steel inserts ( 1 ) .

[0046] The steel insert (s) (1) may be arranged such that substantially the whole first arm may be embedded in the roof. Alternatively, 1 / 2, or 2 / 3, or 3 / 4 of the first arm may be embedded in the roof.

[0047] The first arm may be attached to the roof through the shape of the first arm, e.g. the first arm may have a shape of a dove tail. The steel insert (s) (1) may be additionally or alternatively be attached to the roof through attaching means. The attaching means may extend through the roof of the furnace such that the attaching means are attached to the steel insert (s) (1) in one end and attached to the outside of the roof in another end. When attaching means are used, the steel insert (s) (1) may be partially embedded in the roof of the furnace, or the steel insert (s) (1) may be attached to the attaching means such that the attaching means extends completely through the roof.

[0048] It has been found that the above shape and positioning of the steel insert (s) (1) contribute to the protection of the inner surface (2) of the roof, which would otherwise undergo abrasion due to exposure to extreme temperatures.

[0049] The furnace according to the first aspect may comprise one or more wall (s) , and the steel insert (s) (1) may be arranged at the interface of the roof and the one or more wall (s) , and the second arm may extend along the inner surface (2) of the roof towards the corresponding wall.

[0050] The steel insert (s) (1) being arranged at the interface of the roof and the one or more wall (s) may refer to the distant end of the second arm, i.e. the end of the second arm not connected to the first arm, touching or almost touching the one or more wall(s) .

[0051] The corresponding wall may refer to the wall adjacent to the periphery of the inner surface (2) of the roof on which the steel insert (1) is attached, i.e. the wall creating a 90° or close to 90° angle with the roof .

[0052] The furnace according to the first aspect may comprise a reaction shaft (3) and the inner surface (2) of the roof may be the inner surface (2) of the roof of the rection shaft. The inventors have found that the periphery of the inner surface (2) of the roof of the reaction shaft (3) is particularly exposed to heat when the furnace is in operation. Therefore, the above steel insert (s) (1) have been found to protect the furnace and prolong the lifetime of the furnace. Also, maintenance of the reaction shaft (3) can be reduced.

[0053] The inner surface (2) of the roof may further comprise one or more cooling element (s) (17) .

[0054] A cooling element (17) may refer to a component designed to manage extreme temperatures generated during the process. The cooling elements (17) may contain channels (19) for the flow of cooling water or refrigerants. For the avoidance of doubt, a reference to the inner surface (2) of the roof may refer to the hot side of the cooling element (17) and a reference to the roof of the furnace may refer to the cooling element (s) (17) being an integrated part of the roof. The hot side of the cooling element (17) may refer to the part of the cooling element (17) facing the inside of the furnace.

[0055] The steel insert (s) (1) may be embedded in the a housing (18) of the cooling element (17) . For the avoidance of doubt, the first arm of the L-shape being embedded in the roof may refer to the first arm of the L-shape being embedded in the housing (18) .

[0056] The inventors have found that the steel insert (s) (1) being embedded in the housing (18) results in heat transfer between the steel insert (s) (1) and the housing (18) , which in turn provides further protection against heat for the inner surface (2) of the roof. The inner surface (2) of the roof according to the first aspect may comprise a plurality of steel inserts (1) such that the steel inserts (1) create a frame substantially covering the peripheries of the inner surface (2) of the roof.

[0057] As seen in figure 3, the steel inserts (1) may be arranged at the peripheries of the inner surface (2) of the roof such that the steel inserts (1) create a frame-like structure essentially covering the peripheries of the inner surface (2) of the roof. The roof, such as the roof of the reaction shaft (3) , may have the shape of a cylinder, triangle, square, rectangle, pentagon, hexagon, heptagon, or octagon, or anything there in between. Accordingly, the frame-like structure may have the shape of a cylinder, triangle, square, rectangle, pentagon, hexagon, heptagon, or octagon, or anything there in between. Each straight section of the periphery of the inner surface (2) of the roof may comprise one steel insert (1) , or several steel inserts (1) may be arranged in series to cover the straight section. The steel inserts (1) may be slightly bent to fit a cylindrical or cylindrical-like roof. The steel inserts (1) may all have the same shape and size or they may have slightly different shapes and sizes in order to best create a frame-like structure mimicking the peripheries of the inner surface (2) of the roof.

[0058] It has been found that a frame-like structure of the steel inserts (1) provides surprisingly good protection against heat at the interface between the roof and the walls.

[0059] The furnace according to the first aspect may be a flash smelting furnace, a flash converting furnace, an electric furnace, such as a direct iron reduction furnace, a bath smelting furnace, a bath converting furnace or an electric reduction furnace.

[0060] The inner surface (2) of the roof according to the first aspect may further comprise copper.

[0061] The inner surface (2) of the roof may comprise copper such that the inner surface (2) is covered with copper completely or partially. The inner surface (2) of the roof may be covered partially or completely with cooling elements (17) . The cooling elements (17) may comprise copper. Accordingly, a reference to the inner surface (2) of the roof comprising copper may refer to the inner surface (2) of the roof comprising cooling elements (17) comprising copper and specifically the housing (18) of the cooling element (19) comprising copper .

[0062] The inner surface (2) of the roof according to the first aspect may further comprises bricks.

[0063] The inner surface (2) of the roof may comprise copper and / or cooling elements (17) . The cooing elements may comprise copper. The bricks may be arranged in front of the housing (18) of the cooling elements (17) and / or layer of copper. The bricks being arranged in front of the housing (18) and / or layer of copper may refer to the bricks facing the inside of the furnace and the housing (18) and / or layer copper being arranged between the bricks and the outer part of the roof of the furnace.

[0064] Some of the bricks may be exchanged with a filler material, such as mortar. Mortar may refer to a mixture typically made of a combination of water, sand, and a binder such as cement or lime. The inner surface (2) of the roof of the furnace may comprise further steel inserts embedded in the inner surface (2) of the roof and creating protrusions extending from the inner surface (2) or of the roof. The further steel inserts may have a different shape compared to the steel inserts (1) arranged at the periphery of the inner surface (2) of the roof.

[0065] For example, if the inner surface (2) of the roof comprises bricks, further steel inserts may be arranged between some or all of the bricks.

[0066] The steel insert (s) (1) may comprise steel and in particular high temperature resistant steel and / or high corrosion resistant steel. The steel insert (s) (1) may consist of steel and in particular high temperature resistant steel and / or high corrosion resistant steel.

[0067] A cooling element for a furnace

[0068] According to a second aspect and as seen in figure 3, a cooling element (17) for a furnace is provided, the cooling element (17) comprising a housing (18) , the housing (18) comprising channels (19) for the flow of cooling water or refrigerants, wherein the cooling element (17) further comprises at least one steel insert (1) arranged at the periphery of the hot side of the housing (18) , the at least one steel insert (1) creating a protrusion extending from the cooling element (17) .

[0069] The cooling element (17) may be for a flash smelting furnace, a flash converting furnace, an electric furnace, such as a direct iron reduction furnace, bath smelting furnace, bath converting furnace or electric reduction furnace.

[0070] The housing (18) may refer to the outer structure that contains and protects the channels (19) . The housing (18) may comprise or consist of copper. The channels (19) may comprise copper or consist of copper.

[0071] The hot side of the cooling element (17) may refer to the side of the cooling element (17) that faces the inside of the furnace when the cooling element (17) is used in a furnace. The cold side of the cooling element (17) may refer to the opposite side.

[0072] The steel insert (s) (1) according to the second aspect may have an elongated shape.

[0073] The steel insert (s) (1) according to the second aspect may be L-shaped in the transverse direction.

[0074] The steel insert (s) (1) according to the second aspect may be arranged such that a first arm of the L- shape is embedded in the housing (18) and a second arm of the L-shape extends along the hot side of the housing (18) . The second arm may extend along the hot side of the housing (18) towards the periphery of the housing.

[0075] The steel insert (s) (1) may be arranged such that substantially the whole first arm may be embedded in the housing (18) . Alternatively, 1 / 2, or 2 / 3, or 3 / 4 of the first arm may be embedded in the housing (18) . The first arm may be attached to the housing (18) through the shape of the first arm, e.g. the first arm may have a shape of a dove tail.

[0076] The cooling element (17) may be configured such that it can be used in the roof of a furnace. The furnace may comprise a roof and one or more wall (s) , and the cooling element (17) may be configured such that the steel insert (1) may be arranged at the interface of the roof and the one or more wall (s) , and the second arm may extend along the inner surface (2) of the roof of the furnace towards the corresponding wall. The steel insert (s) (1) being arranged at the interface of the roof and the one or more wall (s) may refer to the distant end of the second arm, i.e. the end of the second arm not connected to the first arm, touching or almost touching the one or more wall (s) .

[0077] It has been found that the peripheries of the inner surface (2) of the roof of a furnace are particularly exposed to hight temperatures during operation of the furnace. The above steel insert (s) (1) and their positioning on the housing (18) have been found to give surprisingly good protection to the areas of the inner surface (2) of a furnace most exposed to heat, when the furnace is used.

[0078] The housing (18) may comprise further steel inserts attached thereto. The housing (18) may also comprise bricks attached thereto.

[0079] The steel insert (s) (1) may comprise steel and in particular high temperature resistant steel and / or high corrosion resistant steel. The steel insert (s) (1) may consist of steel and in particular high temperature resistant steel and / or high corrosion resistant steel.

[0080] Use

[0081] According to a third aspect, the use of the furnace according to the first aspect, or the use of the cooling element according to the second aspect in a furnace, in a direct iron reduction process, electric smelting process, electric reduction process, flash smelting process, flash converting process, bath smelting process or bath converting process is provided.

Claims

CLAIMS1. A furnace having a roof comprising an inner surface (2) , wherein the inner surface (2) of the roof comprises at least one steel insert (1) arranged at the periphery of the inner surface (2) of the roof, the at least one steel insert (1) creating a protrusion extending from the inner surface (2) of the roof.

2. The furnace according to claim 1, wherein the steel insert (s) (1) has an elongated shape.

3. The furnace according to claim 2, wherein the longitudinal direction of the steel insert (s) (1) extend (s) substantially horizontally along the inner surface (2) of the roof.

4. The furnace according to claim 2 or 3, wherein the steel insert (s) (1) is L-shaped in the transverse direction.

5. The furnace according to claim 4, wherein the steel insert (s) (1) is arranged such that a first arm of the L-shape is embedded in the roof and a second arm of the L-shape extends along the inner surface (2) of the roof.

6. The furnace according to claim 5, wherein the furnace comprises one or more wall (s) , and wherein the steel insert (s) (1) is arranged at the interface of the roof and the one or more wall (s) , and wherein the second arm extends along the inner surface (2) of the roof towards the corresponding wall (s) .

7. The furnace according to any preceding claims, wherein the furnace comprises a reaction shaft (3) and wherein the inner surface (2) of the roof is the inner surface (2) of the roof of the rection shaft.

8. The furnace according to any preceding claims, wherein the inner surface (2) of the roof further comprises one or more cooling element (s) (17) .

9. The furnace according to claim 8, wherein the steel insert (s) (1) is embedded in a housing (18) of the cooling element (17) .

10. The furnace according to any preceding claims, wherein the inner surface (2) of the roof comprises a plurality of steel inserts (1) such that the steel inserts (1) create a frame substantially covering the peripheries of the inner surface (2) of the roof.

11. The furnace according to any preceding claims, wherein the furnace is a flash smelting furnace or a flash converting furnace or the furnace according to any of claims 1 to 6 and 7 to 10 wherein the furnace is an electric furnace, such as a direct iron reduction furnace, a bath smelting furnace, bath converting furnace or electric reduction furnace.

12. The furnace according to any preceding claims, wherein the inner surface (2) of the roof further comprises copper.

13. The furnace according to any preceding claims, wherein the inner surface (2) of the roof further comprises bricks.

14. A cooling element (17) for a furnace, the cooling element (17) comprising a housing (18) , the housing (18) comprising channels (19) for the flow of cooling water or refrigerants, wherein the cooling element (17) further comprises at least one steel insert (1) arranged at the periphery of the hot side of the housing (18) , the at least one steel insert (1) creating a protrusion extending from the cooling element (17) .

15. The cooling element according to claim 14, wherein the steel insert (s) (1) has an elongated shape.

16. The cooling element according to claim 15, wherein the steel insert (s) (1) is L-shaped in the transverse direction.

17. The cooling element according to claim 16, wherein the steel insert (s) (1) is arranged such that a first arm of the L-shape is embedded in the housing (18) and a second arm of the L-shape extends along the hot side of the housing (18) .

18. Use of the furnace according to claim 1, or of the cooling element according to claim 14 in a furnace, in a direct iron reduction process, electric smelting process, electric reduction process, flash smelting process, flash converting process, bath smelting process or bath converting process.

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