Stave for a blast furnace

Abstract

The invention relates to a stave (2) for a vertical blast furnace comprising: an inner face (6) configured for contacting an inner surface of the blast furnace wall; and an outer face (8) intended to come into contact with burden inside the blast furnace; wherein the stave comprising a plurality of cavities (4) of a shape that is elongated along a vertical direction (Y) of the blast furnace, corresponding to a direction of burden flow, said cavities being arranged to form ribs (10) extending on the outer face substantially along the vertical direction.

Description

STAVE FOR A BLAST FURNACETechnical field

[0001] The invention relates to the field of blast furnaces, particularly staves for protecting the inner wall of blast furnaces.Background art

[0002] Metallurgical blast furnace staves serve to shield the furnace body’s iron shell from the aggressive effects of burden materials such as ore and coke. A stave known from the art often incorporates pockets and / or metal inserts to mitigate wear.

[0003] Temperatures within the blast furnace can reach up to 1500°C, subjecting the staves to significant physical strain and mechanical stress. To counteract this, staves are generally equipped with integrated cooling channels to regulate temperature.

[0004] However, the extreme heat fluctuations experienced within the blast furnace, coupled with the alternating cooling process, gradually compromise the staves' structural integrity. Over time, this leads to bending of the stave along their central horizontal axis, causing detachment of upper and lower parts of the staves from the inner surface of the furnace walls. Consequently, the lifespan of the staves is significantly reduced, necessitating frequent replacement.

[0005] Published patent document EP 3 540 081 A1 discloses a stave protection system for a metallurgical furnace, comprising a plurality of recesses arranged on a front face of the stave and receiving protruding inserts configured to trap burden material on said front face so as to act as a protective layer for the stave.

[0006] However, the solution disclosed in the document includes room for improvement as it does not effectively address the aforementioned issues regarding the mechanical resilience of the staves to temperature changes.Summary of inventionTechnical problem

[0007] The goal of the present invention is to alleviate at least some of the problems noted in the prior art. In particular, the present invention aims at providing a solution that enhances blast furnace staves’ structural integrity and resistance to deformation, in order to extend their operational lifespan.Summary

[0008] In accordance with a first aspect of the invention a stave for a vertical blast furnace is proposed, comprising: an inner face configured for contacting an inner surface of the blast furnace wall; and an outer face intended to come into contact with burden inside the blast furnace; wherein the stave comprises a plurality of cavities of a shape that is elongated along a vertical direction of the blast furnace, corresponding to a direction of burden flow, said cavities being arranged to form ribs extending on the outer face substantially along the vertical direction.

[0009] According to a preferred embodiment, each of said cavities comprises a vertical length which is at least 1 .5 times larger than its horizontal width.

[0010] According to a preferred embodiment, the cavities are aligned in the vertical direction forming straight vertical ribs, or said cavities are staggered vertically forming vertical zigzag ribs.

[0011] According to a preferred embodiment, the ribs extend continuously along the vertical direction, and being arranged to form multiple vertical rows at intervals in a horizontal direction of said stave.

[0012] According to a preferred embodiment, the ribs form multiple parallel vertical ribs spaced apart from each other exclusively by a horizontal width of the cavities.

[0013] According to a preferred embodiment, each rib comprises a horizontal width which is at most equal to a horizontal width of each cavity.

[0014] According to a preferred embodiment, the cavities comprise a variation of different sizes on the outer face.

[0015] According to a preferred embodiment, the stave comprising a first horizontal row of first cavities, and a second horizontal row of second cavities being bigger in size than the first cavities.

[0016] According to a preferred embodiment, comprising a first vertical row of first cavities, and a second vertical row of second cavities being bigger in size than the first cavities.

[0017] According to a preferred embodiment, the plurality of cavities on the outer face comprises alternating first and second rows.

[0018] According to a preferred embodiment, the cavities comprise a depth within a thickness of the stave presented between the outer face and the inner face, said depth being at most equal to an average horizontal width of each cavity.

[0019] According to a preferred embodiment, the cavities comprise a variation of depths within the thickness of the stave along both the vertical and horizontal directions.

[0020] According to a preferred embodiment, the stave further comprises cooling channels extending within the thickness, the cavities arranged in front of the cooling channels have a smaller depth compared to cavities arranged in front of a portion between two adjacent channels.

[0021] According to a preferred embodiment, each cavity comprises an upper side inner face and a lower side inner face that are both straight along a direction perpendicular to the outer face of the stave, or at least one of said upper side inner face and the lower side inner face being inclined with respect to said direction.

[0022] According to a preferred embodiment, the stave further comprises shapeconforming inserts arranged on at least one of the upper side inner face and the lower side inner face of at least part of the plurality of cavities.

[0023] According to a preferred embodiment, the shape-conforming inserts comprise a tubular portion conforming to a peripheral inner face of the cavities, said tubular portion comprising a curved section connected to an adjacent tubular portion of an adjacent cavity, said curved section being at least partially embedded in a corresponding rib.

[0024] According to a preferred embodiment, the shape-conforming inserts further comprise plain inserts filling the cavities and conforming to the peripheralinner face of said cavities, the stave comprises an alternation of plain inserts and tubular portions along a horizontal and / or vertical row of said cavities.

[0025] According to a preferred embodiment, the plurality of cavities comprises a polygonal or oblong shape, or a combination thereof.

[0026] According to a preferred embodiment, the stave is made of copper (cast iron or hot rolled iron), or cast iron, or steel, or ferrous or non-ferrous alloys.

[0027] The invention further relates to a blast furnace comprising a stave according to the present invention.

[0028] The invention offers significant advantages by enhancing the resistance to deformation of the stave, particularly in response to bending along a horizontal axis. The vertically elongated shape of the plurality of cavities contributes to this improvement, with the formation of vertical ribs providing additional reinforcement against deformation.

[0029] Moreover, the shape-conforming inserts received by the cavities further contribute in solidifying each cavity individually. This results in the formation of a cohesive chain of rows along the cavities, which, in combination with the vertical rows on the outer face of the stave, effectively provide the stave with resistance against deformation and supports high fluctuations in temperature.

[0030] Furthermore, the diversity in cavity sizes and shapes within the stave contributes to optimizing material usage efficiency and enhances heat dissipation, thereby improving the structural integrity of the stave.Brief description of the drawings

[0031] Embodiments of the invention will be described with reference to the following figures, which do not limit the scope of the invention, in which:

[0032] Figure 1 is a schematic perspective view of a stave for a blast furnace according to a first embodiment of the invention, comprising a plurality of cavities of an elongated shape along a vertical direction of the stave;

[0033] Figure 2A is a cross-sectional view of the stave of Figure 1 along a vertical axis A-A, showing upper and lower inner faces of cavities being straight and perpendicular to an outer face of the stave;

[0034] Figure 2B-2D are cross-sectional views of Figure 1 along axis A-A, according to a second embodiment of the invention, showing different configurations of inclination of upper and lower inner faces of cavities;

[0035] Figures 3A-3C are schematic front views of the stave according to a third embodiment of the invention, each showing different examples of cavity arrangements;

[0036] Figures 4A-4B illustrate a front view of the stave according to a fourth embodiment of the invention, comprising a first horizontal row, or vertical row of first cavities, and a second horizontal row, or vertical row of second cavities being bigger in size than the first cavities.

[0037] Figures 5A-5D are schematic perspective views of various design options of shape-conforming inserts intended to be inserted into the cavities of the stave in accordance with embodiments of the invention;

[0038] Figure 6 illustrates a front view of the stave according to a fifth embodiment of the invention;

[0039] Figure 7 shows two cross-sectional views of the stave of Figure 6 along vertical axes B-B and C-C;

[0040] Figure 8 shows a cross-sectional view of the stave of Figure 6 along a horizontal axis D-D;

[0041] Figure 9 illustrates a front view of the stave according to a sixth embodiment of the invention.Detailed description of the drawings

[0042] The figures presented in this document are schematic representations intended for illustrative purposes only. They may not accurately reflect precise dimensions, proportions, or other specific details. Elements shared between each embodiment of the invention will be incremented by 100 in the present description.

[0043] Figure 1 is a schematic perspective view of a stave 2 for a blast furnace according to a first embodiment of the invention. The stave 2 can also be suitable for an electrical arc furnace.

[0044] The stave 2 comprises an inner face 6 configured for contacting, and preferably configured to be attached to, an inner surface of the blast furnace wall (not represented), and an outer face 8 intended to come into contact with burden inside the blast furnace. The burden can consist of at least ore, coke, or a combination of both.

[0045] The vertical direction Y corresponds to a longitudinal direction of the stave 2, the latter being configured to be arranged inside the blast furnace parallel to said vertical direction, which also corresponds to a flow direction of burden descent from an upper inlet of the blast furnace. The vertical direction Y and the horizontal direction X form a plan which is substantially parallel to a plan formed with outer face 8. The direction Z is preferably perpendicular to the inner surface of the blast furnace wall.

[0046] The stave 2 is configured to protect the blast furnace body’s iron shell (wall) from the aggression of ore, and optionally to ensure cooling of said wall via cooling channels (visible in figures 7 and 8) extending in the stave 2 and allowing the circulation of a cold liquid.

[0047] Advantageously, the stave 2 comprises a plurality of cavities 4 of an elongated shape, said elongation being along the vertical direction Y, these cavities 4 are arranged to form ribs 10 extending on the outer face 8 substantially along the vertical direction Y. The term “substantially” indicates that the ribs 10 define an overall extension direction which is vertical or inclined by at most 20° with respect to the vertical direction Y.

[0048] The plurality of cavities 4 preferably comprises at least two cavities 4 forming a horizontal or vertical row, and comprises more preferably at least three cavities which may be vertically or horizontally aligned to form a row, or can be staggered. In an alternative configuration, the vertically extending ribs 10 may not exclusively be formed by the elongated cavities 4, and can be formed by a combination of said cavities 4 of an elongated shape and other various cavities (such as horizontally extending cavities).

[0049] Each of the plurality of cavities 4 preferably comprises a vertical length d which is at least 1 .5 times larger than its horizontal width w, without limiting the invention to these values. More preferably, the horizontal width w isequal to half the vertical length d. The horizontal width w can be comprised between 20mm and 200mm, while the vertical length d can be comprised between 40mm and 400mm.

[0050] For instance, cavity sizes could include 70x140 (with 70 representing the width w, and 140 length d), 50x100 and 90x180. The stave 2 can roughly extend vertically at 2500 mm and horizontally at 1000 mm. The number of cavities 4 and ribs 10 is not limited to what is depicted in figure 1 .

[0051] In this first embodiment, the elongated cavities 4 are uniformly spaced apart horizontally and are aligned vertically, thereby creating straight vertical ribs 10. The vertical rib 10 in the left side of stave 2 is highlighted via a dotted line for ease of visibility.

[0052] The ribs 10 extend continuously in the vertical direction Y, forming multiple vertical rows spaced at intervals along the horizontal axis X of the stave 2. These ribs 10 create multiple parallel vertical structures, with each rib 10 being exclusively separated from its adjacent ribs by the horizontal width w of the cavities 4. Furthermore, each rib’s horizontal width e does not exceed the horizontal width w of each cavity 4.

[0053] In an advantageous manner, the vertically extending ribs 10 efficiently reinforce the stave 2, providing it with sufficient rigidity to withstand folding around the horizontal direction X. This enhances the stave’s resilience against bending, particularly in response to fluctuations in temperature within the blast furnace.

[0054] The cavities 4 are open on the outer face 8 and form pockets which can receive the vertically falling ore and eventually break it by means of their peripheral edges 3. The cavities 4 can be formed by machining, forging or molding.

[0055] Figure 2A is a cross-sectional view, along a vertical axis A-A, of the stave 2 of Figure 1 according to the first embodiment of the invention.

[0056] Each cavity 4 comprises a peripheral inner face 5 having an upper side inner face 5.1 and a lower side inner face 5.2. Both the former and latter being preferably straight and perpendicular to the outer face 8 of the stave 2.

[0057] Figures 2B-2D are cross-sectional views of Figure 1 along axis A-A, according to a second embodiment of the invention, showing different configurations of inclination of the upper side and lower side inner faces 105.1 , 105.2 of the cavities 104.

[0058] Figure 2B depicts a configuration where both the upper face 105.1 and the lower face 105.2 are inclined upwards relative to the perpendicular to the outer face 10. In Figure 2C, both upper and lower inner faces 105.1 , 105.2 are inclined in a convergent manner. Figure 2D shows the upper inner faces105.1 inclined upwards while the lower inner faces 105.2 are straight.

[0059] Alternative configurations for the inclination of the inner faces 105.1 , 105.2 are also possible, including a divergent inclination, or a downward inclination or an upward inclination of the lower inner face 105.2 while the upper inner face 105.1 remains straight.

[0060] These varied configurations of inclination of the upper and lower inner faces 105.1 , 105.2 within the cavities 104 can affect the collection or fragmentation of ore as needed.

[0061] Figures 3A-3C are schematic front views of the stave 202 according to a third embodiment of the invention, each figure showing different examples of shapes and arrangements of the plurality of cavities 204, 204.1 , 204.2,204.3, 204.4, 204.5.

[0062] Preferably, the plurality of cavities of the stave 202 according to the third embodiment of the invention comprises a polygonal shape 204.2, 204.3,204.4, 204.5 or an oblong shape 204, 204.1 , or a combination thereof.

[0063] The stave 202 of the invention may include other secondary cavities 207,207.1 having a shape which is not vertically elongated as the shape of the plurality of elongated cavities 204. For instance, the secondary cavities can include circular cavities 207, hexagonal cavities 207.2, square cavities 207.3, or half the shape of any of the polygonal or oblong shapes, such as half the oblong shape 207.1 depicted in Figure 3A.

[0064] The elongated cavities can include oblong cavities 204, oval cavities 204.1 , rectangular cavities 204.2, double hexagonal-shaped cavities 204.3 (forming single vertically elongated cavities), diamond-shaped cavities204.4, isosceles triangle cavities 204.5, or any other derived polygonal or oblong shape.

[0065] It can be seen in Figures 3B-3C zigzag vertical ribs 211 formed by a staggered arrangement of the elongated cavities 204.3, 204.4, 204.5. These zigzag ribs 211 , provide essentially the same advantages as the straight ribs 210, or ribs 10 of figure 1 .

[0066] The vertical ribs 210 and 211 can be formed solely by an arrangement of the elongated cavities 204-204.5, or by a combination of said elongated cavities and the secondary cavities 207-207.3.

[0067] Advantageously, the mix of elongated cavities 204 and secondary cavities 207 can further enhance structural integrity of the stave 202 and optimize material usage efficiency. The protruding edge 203 of the double hexagonal-shaped cavity 204.3 can improve fragmentation of burden inside the blast furnace.

[0068] Figures 4A-4B illustrate front views of the stave 302 according to a fourth embodiment of the invention, in which the cavities 304’, 304” preferably comprise a variation of different sizes on the outer face 308. The variation of sizes includes both the horizontal width w and the vertical length d, and may further include depth variation of the cavities within a thickness of the stave 302 (ex. as depicted in figure 8).

[0069] The stave 302 of Figure 4A comprises a first horizontal row 312 of first cavities 304’, and a second horizontal row 314 of second cavities 304” being bigger in size than the first cavities 304’.

[0070] Figure 4B illustrates another alternative of the stave 302 according to a fourth embodiment of the invention, comprising a first vertical row 316 of first cavities 304’, and a second vertical row 318 of second cavities 304” being bigger in size than the first cavities 304’.

[0071] Preferably, the plurality of cavities 304’, 304” on the outer face 308 of the stave 302 comprises consistently alternating first rows 312, 316 and second rows 314, 318. In this configuration, the vertical ribs 310 remain extending parallel to one other along the horizontal direction.

[0072] The adjustment of cavity sizes within the stave 302 serves to maintain a uniform and even distribution of material density throughout the entire volume of said stave 302. This can be effectively combined with cooling channels to compensate for the space in front of said channels, for example, by incorporating smaller cavities 304’, while other areas may feature larger cavity sizes.

[0073] Figures 5A-5D are schematic perspective views of various design options of shape-conforming inserts intended to be inserted into the cavities of the stave 2, 102, 202, 302 according to the invention.

[0074] Figure 5A illustrates a preferable design option for the shape-conforming inserts, featuring a tubular portion 20 preferably made from thin-tube sheet metal, comprising a curved section 22.2 connected to an adjacent tubular portion 20, as shown on the right side of Figure 5A. On the left side of Figure 5A, two examples of the tubular portion 20 are depicted during fabrication, each employing different insert cutting solutions. For instance, the cut-out 20.1 enables the creation of the depicted lower curved section 22.2, while cut-outs 20.2 enable the formation of two opposite upper and lower curved sections 22.1 , 22.2 by bending the corresponding metal sheets (visible in the penultimate row of Figure 6).

[0075] The external face 24 of each tubular portion 20 is designed to contact the peripheral inner face of the elongated cavities at least partially along a direction defined by the depth p, while the curved sections 22.2 are configured to be at least partially embedded within the stave thickness (within the corresponding vertical rib), so as the outer edge 22.3 of said curved sections 22.2 is preferably flush with outer face of the stave, or protrudes from said outer face.

[0076] Figure 5B shows another design option for the shape-conforming inserts, comprising a tubular portion 30 having a hollow inner part 32, it is similar to the tubular portion 20 of Figure 5A, however, without cut-outs or curved sections. Figure 5C illustrates a plain insert 40. Figure 5D illustrates a plain insert 50 provided with holes 52 which are preferably filled with a tungsten material.

[0077] The sizes and shapes of the inserts can be oblong or polygonal and can be adapted the cavities of various shapes, such as the ones depicted in figures 3A-3C.

[0078] The inserts 20-50 may consist of or comprise any combination of the following materials: steel and alloys, nickel and alloys (Monel, CuNi...), other ferrous or non-ferrous metals, and ceramics.

[0079] Figure 6 illustrates a front view of the stave 402 according to a fifth embodiment of the invention, it comprises elongated cavities 404 receiving different shape-conforming inserts.

[0080] Preferably, the stave 402 comprises an alternation of plain inserts 40 and tubular portions 20, 30 along a vertical row of said cavities 404, and can alternatively be alternating along at least one horizontal row.

[0081] The final three lower horizontal rows of stave 402 exhibit a sequence of various tubular portions 20. These include a lower curved section 22.1 , two opposing upper and lower curved sections 22.1 , 22.2, and a lower curved section 22.2. All of these curved sections 22.1 , 22.2 are preferably integrated into corresponding vertical ribs of the stave 402.

[0082] Advantageously, the curved sections 22.1 , 22.2, which facilitate the connection of two adjacent tubular portions 20, can horizontally link all the inserts of the cavities 404 within the same row. This creates a cohesive chain of shape-conforming inserts, further enhancing the structural integrity and rigidity of the stave. More particularly, this arrangement helps prevent bending along the vertical direction.

[0083] Preferably, the initial three upper horizontal rows of stave 402 feature a horizontal groove 413 that traverses and extends across all the cavities 404. The depth of this groove is smaller (less deep) than the depth p of each cavity 404, as depicted in Figure 7. These horizontal grooves 413 enable an arrangement of a corresponding lamellar horizontal insert that can further protect the stave, notably the vertical ribs, against abrasion caused by contact with burden.

[0084] Figure 7 shows two cross-sectional views of the stave of Figure 6 along vertical axes B-B and C-C.

[0085] In the left cross-sectional view along axis B-B, the three horizontal grooves 413 are observable, while in the right cross-sectional view along axis C-C, one can discern the difference in depths between the groove 413 and the cavities 404, along with the vertical alternation of the different shapeconforming inserts 30 and 40.

[0086] Additionally, a cooling channel 15 can be observed within stave 402, typically extending vertically and passing through the inner face 406 to connect with the rest of the cooling circuit. Furthermore, multiple cooling channels 15 are incorporated into stave 402, as illustrated in Figure 8.

[0087] Figure 8 shows a cross-sectional view of the stave of Figure 6 along a horizontal axis D-D.

[0088] Here, it is apparent that there is provided an alternating arrangement of thin cavities 404’ and wider cavities 404” in terms of horizontal width. This variation in cavity sizes is intentionally omitted from Figure 6 for clarity of presentation.

[0089] Preferably, the wider cavities 404” are positioned in alignment with the cooling channels 15 and have a shallower depth p1 compared to the thinner cavities 404’, which are situated between two neighboring cooling channels 15 and have a greater depth p2. This diversity in cavity size, encompassing both width and depth, within the stave 402 offers the advantage of preserving a consistent and homogeneous distribution of material density across the entire structure.

[0090] Figure 9 illustrates a front view of the stave 502 according to a sixth embodiment of the invention.

[0091] Preferably, the stave 502 incorporates diabolo-shaped inserts 60 integrated within the stave thickness in corresponding grooves machine on the outer face 508. When said inserts 60 are combined with the tubular portions 30 inserted into the elongated cavities 504, can create a continuous vertical insert, for instance, through welding.

[0092] Advantageously, the diabolo-shaped inserts 60 serve the advantage of linking the various tubular portions 30, facilitating the connection between two vertically adjacent tubular portions 30. This results in a unified chain ofshape-conforming inserts that bolster the structural integrity and rigidity of the stave 502. Specifically, this configuration helps with reinforcing the stave 502 along with the vertical ribs, enhancing its resistance to folding by preventing bending along the horizontal direction.

[0093] It should be highlighted that all disclosed embodiments in this patent document are combinable, each comprising synergistic features aiming to collectively address the technical problem associated with blast furnace staves. The skilled person in the art possesses the capability to combine various embodiments outlined within the patent document to achieve desired outcomes or address specific challenges.

Claims

Claims1 . Stave (2; 102; 202; 302; 402; 502) for a vertical blast furnace comprising:- an inner face (6; 106; 406) configured for contacting an inner surface of the blast furnace wall; and- an outer face (8; 108; 208; 308; 408; 508) intended to come into contact with burden inside the blast furnace; characterized in that the stave (2; 102; 202; 302; 402; 502) comprising a plurality of cavities (4; 104; 204; 204.1 ; 204.2; 204.3; 204.4; 204.5; 304; 404; 504) of a shape that is elongated along a vertical direction (Y) of the blast furnace, corresponding to a direction of burden flow, said cavities being arranged to form ribs (10; 210; 211 ; 310; 410; 510) extending on the outer face (8; 108; 208; 308; 408; 508) substantially along the vertical direction (Y).

2. Stave (2; 102; 202; 302; 402; 502) according to claim 1 , wherein each of said cavities (4; 104; 204; 304; 404; 504) comprises a vertical length (d) which is at least 1.5 times larger than its horizontal width (w).

3. Stave (2; 102; 202; 302; 402; 502) according to any of claims 1 and 2, wherein the cavities (4; 104; 204; 204.3; 204.4; 204.5; 304; 404; 504) are aligned in the vertical direction forming straight vertical ribs (10; 210; 211 ; 310; 410; 510), or said cavities (204.3; 204.4; 204.5) are staggered vertically forming vertical zigzag ribs (211 ).

4. Stave (2; 102; 202; 302; 402; 502) according to any of claims 1 to 3, wherein the ribs (10; 210; 211 ; 310; 410; 510) extend continuously along the vertical direction, and being arranged to form multiple vertical rows at intervals in a horizontal direction of said stave (2; 102; 202; 302; 402; 502).

5. Stave (2; 102; 202; 302; 402; 502) according to any of claims 1 to 4, wherein the ribs (10; 210; 211 ; 310; 410; 510) form multiple parallel vertical ribs spaced apart from each other exclusively by a horizontal width (w) of the cavities (4; 104; 204; 304; 404; 504).

6. Stave (2; 102; 202; 302; 402; 502) according to any of claims 1 to 5, wherein each rib (10; 210; 211 ; 310; 410; 510) comprises a horizontal width (e) which isat most equal to a horizontal width (w) of each cavity (4; 104; 204; 304; 404; 504).

7. Stave (202; 302; 402) according to any of claims 1 to 6, wherein the cavities (204; 204.3; 204.4; 204.5; 304, 404) comprise a variation of different sizes on the outer face (208; 308; 408).

8. Stave (302) according to any of claims 1 to 7, comprising a first horizontal row (312) of first cavities (304’), and a second horizontal row (314) of second cavities (304”) being bigger in size than the first cavities (304’).

9. Stave (302) according to any of claims 1 to 7, comprising a first vertical row (316) of first cavities (304’), and a second vertical row (318) of second cavities (304”) being bigger in size than the first cavities (304’).

10. Stave (302) according to any of claims 8 and 9, wherein the plurality of cavities (304’, 304”) on the outer face (308) comprises alternating first (312; 316) and second rows (314; 318).11 . Stave (2; 102; 202; 302; 402; 502) according to any of claims 1 to 10, wherein the cavities comprise a depth (p; p1 ; p2) within a thickness of the stave (2; 102; 202; 302; 402; 502) presented between the outer face (8; 108; 208; 308; 408; 508) and the inner face (6; 106; 406), said depth (p; p1 ; p2) being at most equal to an average horizontal width (w) of each cavity (4; 104; 204; 304; 404; 504).

12. Stave (402) according to claim 11 , wherein the cavities (404) comprise a variation of depths (p1 , p2) within the thickness of the stave (402) along both the vertical and horizontal directions (Y, X).

13. Stave (402) according to claim 12, wherein said stave further comprises cooling channels (15) extending within the thickness, the cavities (404) arranged in front of the cooling channels (15) have a smaller depth (p1 ) compared to cavities (404) arranged in front of a portion between two adjacent channels (15).

14. Stave (2; 102; 202; 302; 402; 502) according to any of claims 1 to 13, wherein each cavity (4; 104; 204; 304; 404; 504) comprises an upper side inner face (5.1 ;105.1 ) and a lower side inner face (5.2; 105.2) that are both straight along adirection perpendicular to the outer face (8; 108; 208; 308; 408; 508) of the stave (2; 102; 202; 302; 402; 502), or at least one of said upper side inner face (5.1 ;105.1 ) and the lower side inner face (5.2; 105.2) being inclined with respect to said direction.

15. Stave (2; 102; 202; 302; 402; 502) according to claim 14, wherein said stave further comprises shape-conforming inserts (20, 30, 40, 50) arranged on at least one of the upper side inner face (5.1 ; 105.1 ) and the lower side inner face (5.2;105.2) of at least part of the plurality of cavities (4; 104; 204; 304; 404; 504).

16. Stave (2; 102; 202; 302; 402; 502) according to claim 15, wherein the shapeconforming inserts (20, 30, 40, 50) comprise a tubular portion (20) conforming to a peripheral inner face (405) of the cavities (404), said tubular portion (20) comprising a curved section (22.1 , 22.2) connected to an adjacent tubular portion (20) of an adjacent cavity (404), said curved section (22.1 , 22.2) being at least partially embedded in a corresponding rib (410).

17. Stave (2; 102; 202; 302; 402; 502) according to claims 15 and 16, wherein the shape-conforming inserts (20, 30, 40, 50) further comprise plain inserts (40, 50) filling the cavities (404) and conforming to the peripheral inner face (405) of said cavities (404), the stave (404) comprises an alternation of plain inserts and tubular portions along a horizontal and / or vertical row of said cavities.

18. Stave (2; 102; 202; 302; 402; 502) according to any of claims 1 to 17, wherein the plurality of cavities comprises a polygonal (204.2; 204.3; 204.4; 204.5) or oblong shape (4; 104; 204; 204.1 ; 304; 404; 504), or a combination thereof.

19. Stave (2; 102; 202; 302; 402; 502) according to any of claims 1 to 18, wherein said stave is made of cast copper, or cast iron, or cast steel, or cast alloys, or hot rolled copper.

20. Blast furnace comprising a stave according to any of claims 1 to 15.

Images