Hearth forming refractory material and hearth

Abstract

To provide a refractory for forming a hearth which can easily push out coke from a carbonization chamber and is hardly damaged. Another object of the present invention is to provide a hearth from which coke can be easily pushed out of a carbonization chamber and which is less likely to be damaged.SOLUTION: The hearth forming refractory is laid on the hearth of a coke oven and at least one surface of the refractory is formed of fused silica having a porosity of <3.0%. Further, the hearth is formed by laying the refractory for forming the hearth.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a refractory material for forming the hearth of a coke oven and to a hearth. [Background technology]

[0002] As shown in Fig. 1, in a coke oven 1, a number of combustion chambers 12 are constructed by stacking a large number of refractory bricks 121 on a corbel 17 provided above a regenerator chamber 11, and a number of carbonization chambers 13 are formed by the plurality of combustion chambers 12 (see Patent Document 1). Fig. 1 is a cross-sectional view of a portion of the coke oven 1 seen from the pusher side, with the double arrow indicating the furnace battery direction SD. In Fig. 1, a flue (not shown) is provided inside the combustion chamber 12, and the carbonization chamber 13 is formed between the two combustion chambers 12.

[0003] Coal and the like are carbonized in the carbonization chamber 13 to become coke C, which is then removed (see Patent Document 2). FIG. 2 shows how the coke C is removed from the carbonization chamber 13. FIG. 2 is a cross-sectional view of the coke oven 1 perpendicular to the furnace bed direction SD. The coke C is produced by carbonizing coal in the carbonization chamber 13 provided between the hearth 15 and the furnace ceiling 14. When the carbonization is completed, as shown in FIG. 2, the extrusion ram 21 of the extruder 2 is inserted into the carbonization chamber 13 and pushes the produced coke C toward the guide car 4. Then, by inserting the extrusion ram 21 further deeper into the carbonization chamber 13, the coke C is pushed onto the bucket car 3 via the guide car 4.

[0004] Furthermore, Patent Document 3 describes that the monolith crown of a coke oven contains a thermally volume-stable material such as fused silica. However, the monolith crown in Patent Document 3 is formed from a thermally volume-stable material, which is generally made by firing a powder or granular material into a predetermined shape, and when fused silica is used, the porosity is 10 to 25%. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-236896 [Patent Document 2] Japanese Patent Application Publication No. 2024-24909 [Patent Document 3] Japanese Patent Publication No. 2020-176277 [Patent Document 4] Japanese Patent Publication No. 2020-196645 Summary of the Invention [Problem to be solved by the invention]

[0006] As shown in Figure 2, when coke C is removed from the coke chamber 13, the extrusion ram 21 of the extruder 2 is inserted into the coke chamber 13 and the coke C is pushed out from the furnace outlet 16 onto the bucket truck 3 via the guide car 4. At this time, the coke C moves on the hearth 15 in the coke chamber 13 toward the furnace length direction FD. The hearth 15 is formed by laying a hearth-forming refractory material. Conventional hearth-forming refractories have been formed from firebricks.

[0007] An object of the present invention is to provide a hearth-forming refractory that allows coke to be easily pushed out of a coke chamber and is less likely to be damaged. Another object of the present invention is to provide a hearth that allows coke to be easily pushed out of a coke chamber and is less likely to be damaged. [Means for solving the problem]

[0008] The hearth-forming refractory of the present invention is a hearth-forming refractory to be laid in the hearth of a coke oven, and is characterized in that at least one surface thereof is formed from fused silica having a porosity of less than 3.0%.

[0009] The hearth of the present invention is characterized in that it is formed by laying the above-mentioned hearth-forming refractory thereon. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a hearth-forming refractory that, when used in a hearth, allows coke to be easily pushed out of a coke chamber and is less likely to be damaged. Also, it is possible to provide a hearth that allows coke to be easily pushed out of a coke chamber and is less likely to be damaged. [Brief explanation of the drawings]

[0011] [Figure 1] A partial cross-section of a coke oven as seen from the pusher side. [Figure 2] Cross-sectional view of a coke oven showing the removal of coke from the coke chamber. [Figure 3] FIG. 2 is a top view of a hearth in Example 1. [Figure 4] FIG. 10 is a top view of a hearth in Example 2. [Figure 5] FIG. 10 is a perspective view of a hearth in a second embodiment. [Figure 6] FIG. 10 is a top view of a plurality of hearth-forming refractories in Example 2 that are arranged in a wide portion of the hearth. [Figure 7] FIG. 10 is a top view of a plurality of hearth-forming refractories in Example 2 that are arranged in a narrow portion of the hearth. [Figure 8] FIG. 10 is a top view of a plurality of hearth-forming refractories in Example 2 that are arranged in a narrow portion of the hearth. [Figure 9] FIG. 10 is a perspective view of a superstructure of a coke oven formed of precast blocks, which is a modified example of the second embodiment. [Figure 10] FIG. 10 is a top view of a plurality of hearth-forming refractories in a modified example of Example 2 arranged as a narrow hearth. [Figure 11] FIG. 10 is a top view of a hearth in Example 3. [Figure 12] FIG. 10 is a top view of a hearth in Example 4. [Figure 13] FIG. 10 is a top view of the hearth in Example 5. [Figure 14] FIG. 10 is a vertical cross-sectional view of the vicinity of the connection portion of the hearth in a modified example of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] In this application, the direction in which coke C is pushed out of the coke oven 1 is referred to as the furnace length direction FD, and the horizontal direction perpendicular to the furnace length direction FD is referred to as the furnace battery direction SD. In the drawings, the furnace length direction FD is indicated by a double-headed arrow marked FD, and the furnace battery direction SD is indicated by a double-headed arrow marked SD. [Example]

[0013] FIG. 3 shows a top view of the hearth 15 of Example 1. FIG. 3 is a top view of the coke oven 1 with the combustion chamber 12 removed. Both sides of the hearth 15 are the upper surfaces of the corbels 17 located below the combustion chamber 12, and the underside of the hearth 15 is also the corbel 17. The hearth 15 is the underside of the coke chamber 13 shown in FIGS. 1 and 2. The hearth 15 is formed by arranging a plurality of rectangular, plate-shaped hearth-forming refractories 151 in the furnace length direction FD and laying them on the corbels 17. In the hearth 15, adjacent hearth-forming refractories 151 are in contact with each other at a connecting portion 15a. As shown in FIG. 2, when coke C is removed from the coke chamber 13 above the hearth 15, the coke C and the extrusion ram 21 move in the direction of arrow P along the furnace length direction FD in FIG. 3.

[0014] The hearth-forming refractory 151 is a cutout molded product obtained by cutting out a lump (ingot) of fused silica, also known as quartz glass, without crushing it. According to the method described in Patent Document 4, raw silica stone is melted to form molten silica, which is then cooled and solidified after removing air bubbles, thereby producing a lump of fused silica with a porosity of less than 3.0%. The hearth-forming refractory 151 is cut out from the lump of fused silica into a plate shape and molded into the surrounding shape. Fused silica can also be crushed and finely sintered to form a sintered refractory, but this sintered refractory contains many small pores and has a porosity of 10 to 25%. On the other hand, the hearth-forming refractory 151 in Example 1 is a cutout molded product of fused silica, and essentially contains almost no air bubbles. The porosity of the hearth-forming refractory 151 is less than 3.0%. The cutout molded product of fused silica is not only excellent in heat resistance but also hard, allowing for a smooth surface. Therefore, by using the hearth 15 made of hearth-forming refractory 151 made of extruded fused silica in the coke oven 1, it is possible to reduce friction that occurs when the coke C, etc. moves. In addition, the hearth-forming refractory 151 that forms the hearth 15 is made of extruded fused silica, and therefore is hard and has a smooth surface. Therefore, even if the coke C, etc. moves on the upper surface of the hearth 15 as shown in FIG. 2, the hearth 15 is unlikely to be damaged.

[0015] The hearth-forming refractory 151 in Example 1 is entirely formed of a cut-out fused silica molding, but if the upper surface of the hearth 15 that contacts the coke C or the like is made of fused silica, friction with the coke C or the like can be reduced. Therefore, the hearth-forming refractory 151 may have one surface that is a cut-out fused silica molding and the other surface that is a plate made of another material, as long as at least one surface is formed of a cut-out fused silica molding. Furthermore, the hearth-forming refractory 151 may be in the form of a block, as long as it has a surface that is formed of a cut-out fused silica molding. The surface that is formed of a cut-out fused silica molding becomes the upper surface of the hearth 15. [Example]

[0016] Figure 4 shows a top view of the hearth 15 of Example 2. Figure 4 is a top view of the coke oven 1 with the combustion chamber 12 removed. Both sides of the hearth 15 are the upper surfaces of corbels 17 located below the combustion chamber 12, and the underside of the hearth 15 is also corbel 17. The hearth 15 is the underside of the coke chamber 13 shown in Figures 1 and 2. In Figure 4, coke C moves in the direction of arrow P along the furnace length direction FD.

[0017] In the hearth 15 of FIG. 4, a plurality of isosceles trapezoidal plate-shaped hearth-forming refractories 152, each having two opposing sides of different lengths, are laid side by side in the furnace length direction FD on a corbel 17. The hearth-forming refractories 152 of Example 2 have two opposing sides, a short upper base 152a and a long lower base 152b, and two opposing sides, legs 152c and 152d, of the same length. The hearth-forming refractories 152 of Example 2 have peripheral sides that form an isosceles trapezoid. In the hearth 15 of Example 2, a plurality of the hearth-forming refractories 152 are laid side by side in the furnace length direction FD, with the upper bases 152a and the lower bases 152b alternating on one side of the furnace batter direction SD. The legs 152c or legs 152d of adjacent hearth-forming refractories 152 are in contact with each other. The hearth-forming refractory 152 of Example 2 is also a cut-out molded product of fused silica formed into a plate shape, similar to the hearth-forming refractory 151 of Example 1. Therefore, it is possible to reduce friction that occurs when the coke C or the like moves, and the hearth 15 formed with the hearth-forming refractory 152 is less likely to be damaged.

[0018] In Example 2, the legs 152c and 152d of the hearth-forming refractory 152 are adjacent to each other when the hearth 15 is formed, forming a connecting portion 15a. The connecting portion 15a is inclined with respect to the width direction of the hearth 15, which is the furnace battery direction SD. The connecting portion 15a is likely to be uneven, and the unevenness causes resistance when the coke C and the pusher ram 21 move on the hearth 15 in the direction of arrow P. Furthermore, if the connecting portion 15a extends in the furnace battery direction SD, as in Example 1 shown in FIG. 3, resistance may be generated against the coke C and the like moving in the direction of arrow P. However, in Example 2 shown in FIG. 4, the connecting portion 15a is inclined with respect to the width direction of the hearth 15. Therefore, even if the connecting portion 15a is uneven, the force is released when the coke C and the pusher ram 21 move on the hearth 15 in the direction of arrow P, reducing resistance. This makes it easier to push out the coke C than in Example 1. Furthermore, the reduced resistance makes the hearth 15 less susceptible to damage.

[0019] Fig. 5 is a perspective view of the hearth 15 in Example 2. The lower left side of Fig. 5 is a cross section of a plane perpendicular to the furnace length direction FD. Both sides and the bottom of the hearth 15 are corbels 17. The hearth-forming refractories 152 of Example 2 laid on the hearth 15 are plate-shaped. The connection portions 15a of the hearth 15 are inclined with respect to the furnace battery direction SD, which is the width direction of the hearth 15.

[0020] FIG. 6 shows a top view of multiple hearth-forming refractories 152 in Example 2 arranged in a wide portion of the hearth 15, and FIG. 7 shows a top view of multiple hearth-forming refractories 152 in Example 2 arranged in a narrow portion of the hearth 15. The coking chamber 13 shown in FIG. 2 is formed so that its width increases toward the furnace outlet 16 in the furnace length direction FD, and the hearth 15 is also formed to have a wide width. FIG. 6 shows a wide hearth 15 laid on the side closer to the furnace outlet 16. The connecting portion 15a is inclined with respect to the furnace battery direction SD. In FIG. 6, the upper base 152a of one hearth-forming refractory 152 and the lower base 152b of the adjacent hearth-forming refractory 152 are connected in a straight line. Arranging the hearth-forming refractories 152 in this manner allows the width of the hearth 15 to be widened.

[0021] On the other hand, FIG. 7 shows a top view of multiple hearth-forming refractories 152 in Example 2, which are laid as a narrow hearth 15 near the extruder 2. In FIG. 7, the lower bases 152b are pushed inward, and the upper bases 152a protrude outward beyond the dotted line connecting the lower bases 152b. A narrow hearth 15 can be formed by cutting off the portion protruding outward beyond the dotted line and laying the hearth-forming refractories 152. The width of the hearth 15 can be narrowed by pushing the lower base 152b more inward than shown in FIG. 7 and cutting off a larger portion near the upper base 152a. The connecting portion 15a of the hearth 15 is inclined with respect to the furnace bed direction SD, which is the width direction of the hearth 15. The isosceles trapezoidal hearth-forming refractories 152 of Example 2 can be used to form hearths 15 of various widths by cutting off the portion near the upper base 152a, as shown in FIG. 7. The hearth 15 is formed to be narrower as it approaches the pusher side where the extruder 2 is located. Therefore, the hearth 15 can be formed by increasing the pushing depth as described above as it approaches the pusher side and cutting out the vicinity of the upper base 152a. When actually forming the hearth 15, the hearth-forming refractories 152 with the vicinity of the upper base 152a cut out are arranged on the corbel 17.

[0022] To form a hearth 15 whose width gradually increases as described above, it is possible to narrow the width of the hearth 15 shown in Figure 6, in which the upper and lower bases 152a and 152b are linear, by cutting off one side in the furnace bed direction SD. In this case, too, when forming the hearth 15, the cut-off hearth-forming refractories 152 are arranged on the corbels 17 to form the hearth 15. On the other hand, if the lower base 152b is pushed inward as shown in Figure 7, the hearth 15 will extend in the furnace length direction FD. Therefore, by pushing the lower base 152b inward at the narrow portion and cutting off the vicinity of the upper base 152a, the hearth 15 can be formed using a smaller number of hearth-forming refractories 152.

[0023] The hearth-forming refractory 152 having an isosceles trapezoid shape according to Example 2 can be cut away near the lower base 152b to form a narrow hearth 15. Fig. 8 also shows the hearth-forming refractory 152 of Example 2 that is placed in the hearth 15 at a narrow position. In Fig. 7, the hearth-forming refractory 152 is cut away near the upper base 152a, but it may also be cut away near the lower base 152b, as in the hearth-forming refractory 152 shown by the arrow in Fig. 8.

[0024] In the hearth-forming refractory 152 of Example 2, both ends of the lower base 152b have acute corners, and there is a possibility that the acute corners may be chipped during transportation, etc. Even if one or both of the corners of the lower base 152b are chipped, the hearth-forming refractory 152 can be used in the narrow portion of the hearth 15. In that case, as shown in FIG. 8, by cutting out the vicinity of the lower base 152b so that the chip 152e is outside the dotted cut line, it is possible to form a hearth 15 without the chip 152e. Note that, in FIG. 8, only one hearth-forming refractory 152 is cut out near the lower base 152b, but the vicinity of the lower base 152b may be cut out for multiple hearth-forming refractories 152 or all of the hearth-forming refractories 152.

[0025] The combustion chamber 12 of the coke oven 1 in FIG. 1 is constructed entirely of refractory bricks 121. However, the combustion chamber 12 can also be constructed using precast blocks 122 that are larger than the refractory bricks 121. FIG. 9 is a perspective view of the upper structure of the coke oven 1 formed from precast blocks 122, which is a modified example of Example 2. The precast blocks 122 are formed to the width of the combustion chamber 12, and the combustion chamber 12 can be formed by arranging or assembling multiple precast blocks 122. In FIG. 9, three combustion chambers 12 formed from multiple precast blocks 122 are installed with a gap between them to form the coke chamber 13. The top of the combustion chamber 12 and the coke chamber 13 forms the furnace ceiling 14. The furnace ceiling 14 in FIG. 9 is in a state before casters are laid on top. The lower end of the coke chamber 13 forms the hearth 15, in which multiple hearth-forming refractories 152 are laid alternately in the furnace length direction FD. In the hearth 15 of FIG. 9, the hearth-forming refractories 152 of Example 2 are arranged.

[0026] The hearth-forming refractories 152 of Example 2 form a trapezoid with isosceles sides. However, even if the sides are not isosceles, as long as the trapezoid is shaped, the hearth 15 can be formed by rotating adjacent hearth-forming refractories 152 by 180 degrees so that legs of the same length are adjacent at the connecting portion 15a. Fig. 10 shows an example in which the hearth 15 is formed using trapezoidal hearth-forming refractories with isosceles sides. Fig. 10 is a modified example of Example 2, and shows the narrow portion of the hearth 15, similar to Fig. 7. [Example]

[0027] Fig. 11 is a top view of the hearth 15 in Example 3. Like Fig. 3 of Example 1 and Fig. 4 of Example 2, Fig. 11 is a top view of the coke oven 1 with the combustion chamber 12 removed, and both sides of the hearth 15 are the top surfaces of the corbels 17. In Example 3, as shown in Fig. 11, a plurality of parallelogram-shaped, plate-shaped hearth-forming refractories 153 are laid side by side in the furnace length direction FD to form the hearth 15. Like the hearth-forming refractories 151 and 152 in Examples 1 and 2, the hearth-forming refractories 153 in Example 3 are cut-out molded products of fused silica formed into a plate shape, and have low resistance and are resistant to damage.

[0028] 4 to 10, in the hearth 15 of Example 3 shown in Fig. 11, the connection portions 15a where adjacent hearth-forming refractories 153 contact each other are inclined with respect to the width direction of the hearth 15, which is the furnace bed direction SD. Therefore, when the coke C and the extrusion ram 21 move in the direction of arrow P on the hearth 15, resistance is small, and the coke C can be easily extruded. Furthermore, the small resistance makes the hearth-forming refractories 153 less likely to be damaged. [Example]

[0029] FIG. 12 is a top view of the hearth 15 in Example 4. Similar to FIG. 3 of Example 1, FIG. 12 is a top view of the coke oven 1 with the combustion chamber 12 removed, and both sides of the hearth 15 are the upper surfaces of the corbels 17. In Example 4, as shown in FIG. 12, a plurality of parallelogram-shaped plate-shaped hearth-forming refractories 154, 155 are laid side by side on the corbels 17 to form the hearth 15. The hearth-forming refractories 154, 155 are formed in the shape of parallelograms that are symmetrical to each other, and are laid on the hearth 15 side by side in the furnace battery direction SD, with a connecting portion 15b as a boundary. The connecting portion 15b extends in the direction of arrow P. Furthermore, a plurality of hearth-forming refractories 154 are laid side by side in the furnace length direction FD, with a connecting portion 15a as a boundary, and a plurality of hearth-forming refractories 155 are laid side by side in the furnace length direction FD. The hearth-forming refractories 154, 155 are laid two by two in the width direction of the hearth 15 so that their end faces face outward toward the furnace outlet 16, which is in the direction of the tip of the arrow P. The connecting portion 15a is inclined with respect to the furnace battery direction SD, and the portion close to the connecting portion 15b protrudes toward the furnace outlet 16. The arrow P indicates the movement direction of the coke C and the extrusion ram 21 when the coke C is extruded from the carbonization chamber 13. The hearth-forming refractories 154, 155 of Example 4, like the hearth-forming refractories 151 to 153 of Examples 1 to 3, are cut-out molded products of fused silica formed into a plate shape, which have low resistance and are resistant to damage.

[0030] In the hearth 15 of Example 4 shown in Fig. 12, similarly to the hearth 15 of Example 2 shown in Fig. 4, the connection portions 15a, which are the sides where adjacent hearth-forming refractories 154 or adjacent hearth-forming refractories 155 contact each other, are inclined with respect to the width direction of the hearth 15, which is the furnace cell direction SD. Therefore, when the coke C or the extrusion ram 21 moves in the direction of arrow P on the hearth 15, resistance is small, and the coke C can be easily extruded. Furthermore, the small resistance makes the hearth-forming refractories 154, 155 less susceptible to damage.

[0031] As shown in Fig. 11, in the hearth-forming refractory 153 of Example 3, the connection portion 15a is inclined in the same direction as the arrow P, which is the pushing direction of the coke C. Therefore, there is a possibility that the coke C and the like will move to one of the combustion chambers 12 provided on both sides of the carbonization chamber 13. In the hearth 15 of Example 4 shown in Fig. 12, when the coke C and the like move in the direction of the arrow P, the force is released by the connection portion 15a, which is inclined with respect to the width direction of the hearth 15. In addition, since the central portion of the connection portion 15a near the connection portion 15b protrudes toward the furnace outlet 16, the remaining force that is not released is directed toward the center of the hearth 15, and therefore the coke C and the like can be moved in a balanced manner.

[0032] In Example 4, two types of hearth-forming refractories were used: hearth-forming refractories 154 and hearth-forming refractories 155. When using hearth-forming refractories with different front and back surfaces, two types of shapes of hearth-forming refractories are required. However, if the hearth-forming refractory is formed entirely from a cut-out molten silica so that both surfaces can be used as the upper surface, it is possible to manufacture only one type and lay it as shown in Figure 12 by reversing the front and back surfaces. [Example]

[0033] FIG. 13 is a top view of the hearth 15 in Example 5. Similar to FIG. 3 of Example 1, FIG. 13 is a top view of the coke oven 1 with the combustion chamber 12 removed, and both sides of the hearth 15 are the upper surfaces of the corbels 17. In Example 5, as shown in FIG. 13 , a plurality of hearth-forming refractories 156, which are square plates, and hearth-forming refractories 157, which are plates in the shape of right-angled isosceles triangles obtained by cutting the square hearth-forming refractories 156 diagonally, are laid side by side in the hearth 15. The hearth-forming refractories 156 and 157 are plate-shaped. The hearth-forming refractories 156 are laid side by side in the furnace length direction FD so that each side is inclined 45 degrees relative to the furnace length direction FD and the furnace battery direction SD, and the hearth-forming refractories 157 in the shape of right-angled isosceles triangles are laid in the remaining triangle locations. Like the hearth-forming refractories 151 to 155 of Examples 1 to 4, the hearth-forming refractories 156 and 157 of Example 5 are cut-out molded products of fused silica formed into plates, which have low resistance and are resistant to damage.

[0034] 4, 11, and 12, in the hearth 15 of Example 5 shown in Fig. 13, as in the hearth 15 of Examples 2 to 4 shown in Figs. 4, 11, and 12, the connection portion 15a, which is the side where the adjacent hearth-forming refractories 156 and 157 meet, is inclined with respect to the width direction of the hearth 15, which is the furnace bed direction SD. Therefore, when the coke C and the extrusion ram 21 move on the hearth 15 in the direction of arrow P, resistance is small, and the coke C can be easily extruded. Furthermore, the small resistance makes the hearth-forming refractories 156 and 157 less likely to be damaged.

[0035] The hearth 15 of Example 5 used a square hearth-forming refractory 156 and a hearth-forming refractory 157 in the shape of a right-angled isosceles triangle obtained by cutting the hearth-forming refractory 156 diagonally. However, two right-angled isosceles triangular hearth-forming refractories 157 may be laid in place of the square hearth-forming refractory 156 with their bases aligned along the furnace length direction FD. In this case, the hearth 15 can be formed using only one type of hearth-forming refractory 157. Alternatively, the square hearth-forming refractory 156 may be cut on-site to produce a right-angled isosceles triangular hearth-forming refractory 157. In this case, the square hearth-forming refractory 156 without acute corners can be transported to the site, thereby reducing the possibility of damage to the hearth-forming refractory 156. [Example]

[0036] In Examples 1 to 5, the hearth-forming refractories 151 to 157 are not bonded together at the connecting portions 15a, but are arranged side by side to form the hearth 15. However, the hearth 15 may be formed by bonding these together at the connecting portions 15a. FIG. 14 shows a vertical cross-sectional view of the vicinity of the connecting portion 15a of the hearth 15 in Example 6. The hearth-forming refractory 158 has a chamfered portion 158a at its top. A depression is formed at the connecting portion 15a of two adjacent hearth-forming refractories 158. The depression is then filled with a connecting material 159. In Example 6, the connecting material 159 is made of fused silica with low porosity.

[0037] 14, hearth-forming refractories 158 each having a chamfered portion 158a are arranged, and the depressions formed by the chamfered portions 158a are filled with granular or other fused silica. The granular or other fused silica is then melted by burner melting at approximately 2,000°C to connect two adjacent hearth-forming refractories 158. As the connecting material 159, instead of fused silica, mortar or the like used to connect the firebricks 121 and precast blocks 122 can also be used.

[0038] By connecting the adjacent hearth-forming refractories 158 to each other using the connecting material 159 at the connecting portion 15a, the hearth 15 becomes more easily slippery for the coke C and the like, and damage to the hearth 15 is reduced. The shape of the hearth-forming refractories 158 and the installation direction on the hearth 15 may be any of those in Examples 1 to 5, or may be other. Note that even if the hearth is connected as shown in FIG. 14, there is a possibility that unevenness may occur in the connecting portion 15a. Therefore, it is more effective to use a hearth 15 having connecting portions 15a that are inclined with respect to the width direction of the hearth 15, as in Examples 2 to 5.

[0039] The joints 15a of the hearth-forming refractories in Examples 2 to 6 are all inclined with respect to the width direction of the hearth 15. When laid, none of the joints 15a extend in the width direction of the hearth 15. However, the configuration in which the joints 15a of the hearth-forming refractories in Examples 2 to 6 are inclined with respect to the width direction of the hearth 15 achieves effects such as resistance reduction even if they are not formed over the entire length of the hearth 15. Near the furnace outlet 16 of the coke C, the coke C moves on the hearth 15 throughout the entire period during which the coke C is being pushed out. Therefore, when the joints 15a of the hearth-forming refractories are partially inclined, it is preferable that the joints 15a be formed in the hearth 15 closer to the furnace outlet 16 than in the hearth 15 farther from the furnace outlet 16. Therefore, the joints 15a of the hearth-forming refractories may be inclined in the hearth 15 closer to the furnace outlet 16 and not inclined in the hearth 15 farther from the furnace outlet 16. For example, the connecting portion 15a may be inclined in a region of 50% of the furnace length close to the furnace outlet 16, and the sides of the remaining region may extend in the furnace battery direction SD as in the first embodiment.

[0040] The hearth-forming refractories of Examples 1 to 6 are cut-out shaped pieces cut into plates from a fused silica ingot. However, if the surface of the hearth-forming refractory on which the coke C is placed is the same as the cut-out shaped piece cut into plates from a fused silica ingot, the coke C can be easily pushed out of the coking chamber, and a hearth-forming refractory that is less likely to be damaged can be provided. Therefore, in the hearth block, granular fused silica may be placed on the side on which the coke C is placed, and the granular fused silica may be melted by burner melting or the like to form fused silica with a porosity of less than 3.0% near the surface. Alternatively, the surface of a sintered fused silica refractory may be melted by burner melting or the like to reduce the porosity and make the porosity near the surface less than 3.0%.

[0041] Furthermore, the specific configuration is not limited to the examples and modifications, and the present invention also includes design changes within the scope of the gist of the present invention. Furthermore, the above-described examples and modifications can be combined by utilizing each other's technology as long as there are no particular contradictions or problems in the purpose, configuration, etc. [Explanation of symbols]

[0042] 1. Coke oven 11 Heat storage chamber 12 Combustion chamber 121 Firebrick 122 Precast Blocks 13 Carbonization chamber 14 Furnace roof 15 Hearth 15a Connection 15b Connection 151 Refractories for hearth formation 152 Refractories for hearth formation 152a Upper bottom 152b Bottom bottom 152c legs 152d legs 152e chipped 153 Refractories for hearth formation 154 Refractories for hearth formation 155 Refractories for hearth formation 156 Refractories for hearth formation 157 Refractories for hearth formation 158 Refractories for hearth formation 158a Chamfered part 159 Connectors 16 Furnace outlet 17 Corbel 2. Extruder 21 Extrusion Ram 3 Bucket truck 4 Guide car FD furnace length direction SD Furnace Batteries Direction C Coke

Claims

1. A hearth-forming refractory material laid on the hearth of a coke oven, A refractory for forming a hearth, at least one surface of which is formed from fused silica having a porosity of less than 3.0%.

2. 2. The hearth-forming refractory according to claim 1, wherein the entire refractory is made of fused silica having a porosity of less than 3.0%.

3. 2. The hearth-forming refractory material according to claim 1, which is a cut-out molding from a fused silica ingot.

4. 3. The hearth-forming refractory material according to claim 1, wherein the peripheral sides form a trapezoid.

5. A hearth characterized by being formed by laying the hearth-forming refractory material according to any one of claims 1 to 3.

6. 6. The hearth according to claim 5, wherein the connecting portions of the hearth-forming refractories are inclined with respect to the width direction of the hearth.

7. 7. The hearth according to claim 6, wherein the hearth-forming refractory material comprises a square plate and a plate in the shape of a right isosceles triangle obtained by cutting the square plate diagonally.

8. 7. The hearth according to claim 6, wherein the hearth-forming refractory material is a trapezoidal plate.

9. The hearth-forming refractory is a parallelogram plate, 7. The hearth according to claim 6, wherein two sheets are laid across the width of the hearth so that the end faces face inward toward the furnace outlet.

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