JP2017057496A - Block door of converter type refining furnace and operation method of converter type refining furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a slug from sticking to a meeting position in a converter type refining furnace that performs intermediate waste discharge.SOLUTION: A converter type refining furnace includes a first door part that has a first meeting part on one end side in an uniaxial direction and can cover a part of a furnace front side opening part of a fixed wall of the converter type refining furnace, and a second door part that is disposed in parallel with the first door part in the uniaxial direction, has a second meeting part on one end side opposite to the first door part, and can partially cover the furnace front side opening part, in which, in a state where the first meeting part and the second meeting part meet and the first door part and the second door part cover and close the furnace front side opening part, a first distance d in the direction in parallel with the uniaxial direction of a meeting position where the first meeting part and the second meeting part meet and a center position of the throat of a furnace body is larger than 0 m, and a relationship between a radius r of the throat, a second distance L between the throat and a furnace front floor, and a height from a center of a trunnion rotation axis of the furnace body to the throat satisfies a formula (1): d/r≥1-3 L/H.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a shut-off door for a converter-type refining furnace and a method for operating the converter-type refining furnace.

  In recent years, when carrying out acid refining to dephosphorize or decarburize hot metal using one converter-type smelting furnace, only slag is discharged while holding the hot metal in the furnace of the converter-type smelting furnace ( A method has been put to practical use in which an intermediate waste removal process is also performed in the middle and acid refining is continuously performed in two stages. For example, Patent Document 1 discloses that after the dephosphorization process, the converter is tilted while leaving the hot metal in the converter, and only the slag is discharged. Thereafter, the decarburization refining is performed in the same converter, A method is disclosed in which the later slag is reused for the subsequent dephosphorization of hot metal. Patent Document 2 discloses a hot metal preliminary treatment (dephosphorization) in which a single converter-type refining furnace is used to continuously perform desiliconization treatment and dephosphorization treatment of hot metal with an intermediate waste removal step in between. A method is disclosed.

In these methods, the use of a CaO-based medium solvent in the subsequent treatment is performed by discharging slag in the middle compared with a refining method in which acid refining is continued without performing intermediate waste in the middle. There is an advantage that the amount can be reduced.
In addition, after performing the first-stage acid refining, not only slag but also molten iron is once discharged from the refining furnace and transferred to the same refining furnace or another refining furnace, and then the second-stage acid refining is performed. Compared with this method, (i) the time required for hot metal tapping and recharging can be shortened and the operating rate of the converter-type refining furnace can be increased. (Iii) The amount of CaO-based solvent used can be reduced by leaving the slag of the second-stage acid refining in the furnace and reusing it for the first-stage acid refining of the next hot metal. (Iv) reducing the discharge of the second-stage acid refining slag with high basicity and increasing the discharge of the first-stage acid refining slag with relatively low basicity Therefore, it is possible to improve the hydration expansion characteristics of slag and promote the use of slag Kill, there is an advantage in that.

In order to enjoy these advantages, an important operational point is how quickly a target amount of slag is discharged from the furnace in the intermediate evacuation process. When the amount of slag discharged in the intermediate evacuation process is small, the effect of reducing the amount of CaO-based solvent used as described above cannot be expected, and the amount of CaO-based solvent used is evacuated midway. Not much different from no method.
Therefore, in Patent Document 1 and Patent Document 2, there is a method for forming molten slag in the first-stage acid refining to increase the volume of the molten slag in order to efficiently discharge in the intermediate discharging process. It is disclosed. In Patent Document 1 and Patent Document 2, by increasing the volume of the molten slag, the height of the slag bath surface from the lower end of the furnace port can be increased during intermediate discharge from the furnace port, and the overflow of molten slag The discharge efficiency by the flow can be increased. Here, slag forming is a phenomenon in which molten slag contains bubbles and apparently expands in volume.

However, if the molten slag discharge speed is increased, the molten slag may flow up to the operation floor on the front side of the furnace, so at the time of intermediate evacuation, a fixed-wall furnace that is part of the partition wall surrounding the furnace body with a shut-off door It is necessary to cover the front opening.
In general, in a converter-type refining furnace, in order to prevent the occurrence of disasters such as deterioration of the working environment and fire due to the scattering of high-temperature substances to the operation floor and the outflow of smoke, as disclosed in Patent Document 2, for example, A partition wall is provided between the furnace body and the space on the operation floor so as to surround the furnace body of the furnace type refining furnace. This partition generally has a fixed wall and a blocking door that is a moving wall that movably covers the open front side of the fixed wall. The shut-off door moves by, for example, running on the rail installed on the operation floor in front of the furnace, and is opened whenever hot metal or scrap is charged into the furnace body. It is closed so as to cover the open part on the furnace front side of the fixed wall. At this time, if the moving speed of the blocking door is too high, troubles such as derailment due to deposits on the rails may be caused, so the moving speed of the blocking door is limited. However, when the moving speed of the shut-off door is extremely slow, the open / close time of the shut-off door becomes long, which contributes to a decrease in productivity of the converter-type refining furnace equipment.

  In order to shorten the opening / closing time by reducing the moving stroke of the blocking door, the blocking door is often a double-open structure divided into two left and right. However, in the case of a converter-type refining furnace that frequently performs intermediate waste, the molten slag is likely to flow into a small gap at the summing position of the shut-off door during the intermediate waste, so the molten slag is There was a possibility of solidifying and adhering to the summing position of the operation floor. The deposits are gradually deposited and grown by repeated intermediate evacuation. If the deposit becomes too large, the blocking door cannot be closed and the blocking door will not function. Moreover, since extra work time is required when removing the deposits, the productivity is adversely affected.

JP 2008-255446 A JP-A-4-362112

  Therefore, the present invention has been made paying attention to the above-mentioned problem, and in a converter type refining furnace that performs intermediate waste, a converter type refining furnace that can suppress adhesion of slag to the summing position. The purpose is to provide a method for operating the shut-off door and converter-type refining furnace.

According to one aspect of the present invention, a converter type refining furnace has first moving means that can move in a uniaxial direction parallel to the horizontal direction, and a first summing portion on one end side in the uniaxial direction. A first door part capable of covering a part of the front opening part of the fixed wall that is a part of a partition wall surrounding the furnace body, and the first door part and the first door part are arranged side by side in the uniaxial direction, The second moving means movable in the uniaxial direction, and the second summing portion on one end side in the uniaxial direction facing the first door portion, partially covering the furnace front side opening portion. A second door portion capable of being combined, wherein the first summing portion and the second summing portion are combined, and the first door portion and the second door portion allow the front side of the furnace In a closed state where the open part is covered, a summing position where the first summing part and the second summing part are combined, and a furnace opening of the furnace body From the state where the first distance d [m] in the direction parallel to the uniaxial direction with respect to the center position is larger than 0 m, the radius r [m] of the furnace port, and the furnace body upright, A second distance L [m] between the furnace port and the furnace front floor at a position tilted 90 degrees to the side, and a height H [m] from the center of the trunnion rotation axis of the furnace body to the furnace port Therefore, there is provided a shut-off door for a converter-type refining furnace characterized in that the relationship with the above satisfies the expression (1).
d / r ≧ 1-3 L / H (1)

  According to one aspect of the present invention, a primary acid refining step for supplying oxygen gas to the hot metal accommodated in a furnace body of a converter type refining furnace, and sending the hot metal by acid refining, and a primary acid refining step, Then, while the hot metal accommodated in the furnace body remains in the furnace body, the furnace body is tilted so that the furnace port of the furnace body is located on the front side of the furnace, and the primary acid refining step An intermediate waste process for discharging at least a part of the slag produced in the furnace from the furnace port, and after the intermediate waste process, supplying the oxygen gas to the molten iron remaining in the furnace body, and further acid refining A secondary acid feed refining step, wherein the intermediate waste step includes a first moving means movable in a uniaxial direction parallel to the horizontal direction and a first summing portion on one end side in the uniaxial direction. And a part of the open part on the furnace front side of the fixed wall that is part of the partition wall surrounding the furnace body. Door portion, the first door portion and the second moving means arranged side by side in the uniaxial direction and movable in the uniaxial direction, and one end side in the uniaxial direction facing the first door portion And a second door part capable of covering a part of the open side on the furnace front side with a second summing part, the first summing part and the second summing part. The slag is discharged from the furnace port in the closed state where the first door part and the second door part cover the furnace front side open part, and the closed. In the state, a first position in a direction parallel to the uniaxial direction between a summing position where the first summing part and the second summing part are combined with a center position of the furnace port of the furnace body. The distance d [m] is larger than 0 m, the radius r [m] of the furnace port, and the furnace body upright from the state where the furnace body is upright is 9 The relationship between the second distance L [m] between the furnace port and the front floor of the furnace at the tilted position, and the height H [m] from the rotation axis center of the trunnion of the furnace body to the furnace port Satisfies the equation (1). A method for operating a converter-type refining furnace is provided.

  According to one aspect of the present invention, it is possible to suppress the adhesion of slag to a summing position in a converter type refining furnace that performs intermediate waste.

It is a front view which shows the converter type | mold refining furnace in the state which the furnace body tilted and the interruption | blocking door closed. It is a front view which shows the converter type | mold refining furnace in the state in which the furnace body stood upright and the cutoff door was closed. It is a front view which shows the converter type refining furnace in the state where the furnace body stood upright, and the shut-off door opened. It is a top view which shows a converter type refining furnace. It is a side view which shows a converter type refining furnace. It is explanatory drawing which shows the operating method of the converter type refining furnace which concerns on one Embodiment of this invention. In an Example, it is a graph which shows the influence which the relationship between d / r and L / H has on the slag adhesion to the summing position of the blocking door.

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. However, it will be apparent that one or more embodiments may be practiced without such specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
<Configuration of the shut-off door of the converter type refining furnace>
First, with reference to FIGS. 1-5, the shutoff door of the converter type refining furnace which concerns on one Embodiment of this invention is demonstrated. The converter-type refining furnace 1 is a refining apparatus that performs acid refining of hot metal, and includes a furnace body 2, a partition wall 3, and a dust collection facility 4 as shown in FIG. 1.

  The furnace body 2 is a refining vessel having a furnace port 21 that is an opening at the upper part on the z-axis positive direction side that is the vertical direction in an upright state as shown in FIG. 2, and a refractory is provided on the entire inner wall. . In addition, the furnace body 2 has a pair of trunnions 22 (cylinder ears) at both ends on the x-axis direction side which is the horizontal direction, and in the x-axis direction by a tilting device (not shown) connected to the pair of trunnions 22. It is configured to be tiltable about the axis of a pair of parallel trunnions 22. Moreover, the furnace body 2 is provided in an upright state so that a part of the lower side in the vertical direction is lower than the front floor 5 of the furnace.

  The partition wall 3 is a wall that surrounds a region on the upper side (z-axis positive direction side) of the furnace front floor 5 of the furnace body 2, and includes a fixed wall 31 and a blocking door 32. The fixed wall 31 is formed so as to surround the furnace body 2, and has a furnace front side opening portion 311 that is partially open on the y axis negative direction side perpendicular to the x axis and the z axis that are the furnace front side. The furnace front side open part 311 is a rectangular opening region, and is formed at a predetermined height including a part of the dust collection equipment 4 from the furnace front floor 5. The blocking door 32 is a movable wall composed of a first door portion 32a and a second door portion 32b.

  The first door portion 32a has a substantially rectangular shape capable of covering a part of the furnace front side opening portion 311 and includes the first moving means 321a and the first end of the x-axis negative direction side end portion. A summing unit 322a and a first protective plate 323a are provided. A cooling member such as a steel pipe is provided in a predetermined region on the lower end side which is the z-axis negative direction side on the surface on the y-axis positive direction side of the first door portion 32a. The cooling member is cooled by flowing cooling water therein. In addition, the predetermined region on the surface on the y-axis positive direction side of the first door portion 32a is a region where slag discharged from the furnace port 21 may be applied in the intermediate evacuation step described later or from the inside of the furnace. It is provided so as to include a region that receives strong radiant heat. The first moving means 321a is a pair of wheels provided side by side in the x-axis direction at the lower end of the first door portion 32a, and the x-axis direction is a uniaxial direction parallel to the horizontal direction on the furnace front floor 5 It is arranged on a rail (not shown) provided so as to extend. The first moving means 321a is connected to a driving device such as a motor (not shown) provided in the first door portion 32a, and rotates by receiving the driving force of the driving device. 32a is moved along the x-axis direction. As shown in FIGS. 4 and 5, the first protective plate 323a extends from the first summing portion 322a in the x-axis positive direction at the lower end portion of the first door portion 32a, and the furnace body 2 Projecting to the positive y-axis direction side. The upper surface of the first protective plate 323a is inclined so that the height on the y-axis positive direction side is low, and the first protection plate 323a is provided to extend in the y-axis positive direction from the furnace front floor 5.

  The second door portion 32b has a substantially rectangular shape capable of covering a part of the furnace front side opening portion 311. The second moving means 321b and the second end of the x-axis positive direction side end portion. A summing unit 322b and a second protective plate 323b are provided. On the surface of the second door 32b on the positive side in the y-axis, a cooling member such as a steel pipe is provided on a predetermined region on the lower end side that is on the negative side of the z-axis as necessary, as with the first door 32a. Is provided. The second moving means 321b is a pair of wheels similar to the first moving means 321a, and is arranged on the same rail as the first moving means 321a arranged on the rail on the furnace front floor 5. Further, the second moving means 321b is connected to a driving device such as a motor (not shown) provided in the second door portion 32b, and rotates by receiving the driving force of the driving device. 32b is moved along the x-axis direction. Similarly to the first protection plate 323a, the second protection plate 323b extends from the second summing portion 322b in the negative x-axis direction to the lower end portion of the second door portion 32b, and the furnace body 2 Projecting to the positive y-axis direction side. The upper surface of the second protective plate 323b is inclined so that the height on the y-axis positive direction side is low, and the second protection plate 323b extends from the furnace front floor 5 in the y-axis positive direction.

The blocking door 32 is a double-open door, and opens and closes when the first and second door portions 32a and 32b are moved in the horizontal direction by the first and second moving means. At this time, as shown in FIGS. 1 and 2, the state in which the first summing unit 322 a and the second summing unit 322 b are combined and the furnace front side opening unit 311 is covered is the state where the shut-off door 32 is closed. It becomes. On the other hand, as shown in FIG. 3, the state in which the first summing unit 322 a and the second summing unit 322 b are separated and the furnace front side opening unit 311 is opened is the state in which the blocking door 32 is opened. . In a state where the shutoff door 32 is closed,召合allowed position P _a and first convene mating portion 322a and the second convene mating portion 322b is x-axis direction position mated is, the center position P _c of the furnace opening 21 On the other hand, the first distance d [m] is shifted in the x-axis direction.

Here, the first distance d is larger than 0 m and satisfies the following expression (1). In equation (1), r is the radius [m] of the furnace port 21, and L is the furnace port 21 at a position where the furnace body 2 is tilted 90 degrees from the upright state to the side of the hot water as shown in FIG. And the second distance [m] in the y-axis direction between the furnace front floor 5 and H is the height [m] from the rotation axis center of the trunnion 22 of the furnace body 2 to the furnace port 21 (in the y-axis direction in FIG. 5). Height). When the furnace port 21 is not circular, r is ½ of the diameter of the furnace port 21 in the x-axis direction.
d / r ≧ 1-3 L / H (1)

Further, in addition to the condition of the first distance d, the value d / r of the ratio of the first distance d to the radius r is preferably 0.2 or more, and more preferably 0.86 or more. .
Further, the widths W1 and W2 in the x-axis direction of the rectangular area covering the furnace front side opening part 311 of the first and second door parts 32a and 32b have a length obtained by adding the width W1 and the width W2 to the furnace front side opening part. It is formed to have a length equal to or greater than 311 in the x-axis direction. Furthermore, when the value d / r of the ratio of the first distance d to the radius r is 0.20 or more, the length of the width W1 is not less than 1.25 times and not more than 4.0 times the length of the width W2. It is preferable that it is 1.8 times or more and 3.0 times or less.

  In addition, the furnace front floor 5 is disposed at a position lower (on the z-axis negative direction side) than the center of the rotation axis of the trunnion 22 so that maintenance and inspection of the rotary drive system of the furnace body 2 can be easily performed. Moreover, since the height of the trunnion 22 is restricted from the viewpoint of suppressing the construction cost of the factory, and the height of the furnace front floor 5 needs to be higher than the height at which the ladle or the like can pass below, The height from the front floor 5 to the center of the rotation axis of the trunnion 22 is usually about ½ or less of the height H.

  The dust collection equipment 4 sucks the exhaust gas and dust discharged from the furnace port 21 of the furnace body 2 during acid refining, intermediate waste, and hot water, and separates and recovers gas components and dust in the exhaust gas. Equipment. The dust collection equipment 4 includes a skirt 41 that can be raised and lowered in the z-axis direction, and a hood 42 connected to the upper part of the skirt 41. The exhaust gas generated from the furnace port 21 is sent to an exhaust gas recovery device (not shown) via the skirt 41 and the hood 42, and is separated and recovered.

<Operation method of converter refining furnace>
Next, with reference to FIG. 6, the operation method of the converter type refining furnace 1 which concerns on this embodiment is demonstrated. In the present embodiment, using one converter-type refining furnace 1, the desiliconization process and the dephosphorization process of the hot metal discharged from the blast furnace are continuously performed. First, as shown in FIG. 6 (A), the hot metal accommodated in the hot metal ladle 6 is placed in the furnace body 2 tilted to the side of the reaction hot water so that the furnace port 21 is located on the front side of the furnace with the trunnion 22 as the center. The hot metal M is charged into the furnace body 2 by pouring M from the furnace port 21 (charging process). The charging step, before the hot metal M is charged in advance, the interior of the furnace body 2, a cold iron source S _c scrap and the like are accommodated. Further, in the charging process, when the hot metal M is charged, the blocking door 32 is opened, and after the charging process is completed, the closing door 32 is closed, and the blocking door 32 is opened. Closed state.

Next, as shown in FIG. 6 (B), the furnace body 2 is erected, oxygen gas is blown from the acid feed lance 7, and oxygen gas is supplied to the hot metal M to perform desiliconization treatment (desiliconized blowing). Perform (primary acid refining process). At this time, the desiliconization process is performed with the blocking door 32 closed. In the primary acid refining process, an oxygen source is supplied into the furnace, and further a combustion heat source such as a CaO-based solvent or a silicon source is supplied as necessary. Also, in the primary acid refining process, the implementation conditions are controlled so that the slag S _l is appropriately formed in order to enhance the slag S _l generated in the intermediate evacuation process of the next process in order to improve the slag S _l generated in the desiliconization process. Is done. Further, in the primary acid refining process, the inert gas is blown into the hot metal M from the bottom blowing nozzle 23 provided at the bottom of the furnace body 2, and the stirring force of the hot metal M is increased, thereby promoting the desiliconization reaction. The primary acid feeding refining process ends when a predetermined amount of oxygen gas is blown according to the silicon concentration of the hot metal M, the hot metal amount, the added amount of the auxiliary material, and the like.

Furthermore, as shown in FIG. 6 (C), by tilting to the furnace body 2 throat 21 is positioned in the furnace front, at least a portion of the slag S _l after desiliconizing treatment from the furnace body 2 The intermediate waste to be discharged is performed (intermediate waste process). Intermediate in Haikasu step, by tilting the furnace body 2 in the counter-tapping side, to discharge only mild slag S _l specific gravity that floats on the bath surface from the throat 21. Slag S _l, which is discharged in the middle Haikasu process is accommodated in溶滓container (not shown) disposed in the lower furnace body 2 (Haikasunabe). Emissions of slag S _l in the intermediate Haikasu step, in order to reduce the amount of CaO-type medium solvent in the secondary oxygen-flow refining process of the next step effectively, the furnace body at the end of the primary oxygen-flow refining process It is desirable that the amount of slag S _{1 in} 2 is about half or more. In the present embodiment, in the primary oxygen-flow refining process, for controlling the execution condition as slag S _l is forming moderately, intermediate drain in a state in which slag S _l is forming, and increased surface levels of the slag layer A trap is performed. Therefore, it is possible to discharge the slag S _l efficiently.

At this time, the higher the height of the surface of the slag S _l in the furnace at the upright when the furnace body 2, the outflow of slag S _l begins at a small tilt angle, as the tilt angle is increased, the position and the throat 21 with the angle changes, the discharge rate of slag S _l is increased. Tilting angle of the furnace body 2 is optionally adjusted so that the discharge rate of slag S _l is the appropriate range, finally molten iron M increases to 90 degrees near the extent that does not flow out. Incidentally, lead to reduction of the extension and Haikasu amount of the discharge rate of slag S _l is too small Haikasu time, the slag S _l the discharge rate of slag S _l is scattered without being accommodated in too large Haikasu pot ratio or increasing, there is a problem that the amount of molten iron which flows mixed in the slag S _l is or increases. For this reason, the tilt angle of the furnace body 2 is adjusted so that the discharge speed is appropriate from these viewpoints.

In addition, the shape of the furnace port 21 where the slag S ₁ overflows while the slag S _l is discharged has an arc shape in which the height and depth viewed from the front side of the furnace change according to the tilt angle of the furnace body 2. It becomes a shape. Higher height from the lower end of the arcuate shape to the surface of the slag S _l in the furnace increases, with increasing flow rate of the slag S _l driving force for discharging the slag S _l is increased, along an arc shape since the slag width S _l exhaust stream (x-axis direction length) also increases Te, tends to discharge speed of slug S _l is increased. At this time, the discharge flow of the slag S _l, the flow rate is larger than the width direction end portion toward the widthwise center. Further, the shape of the arcuate section, the outflow position of the slag S _l is a position away horizontally from the axis of the trunnion 22 than the width direction end portion toward the widthwise center portion of the exhaust stream. Because the discharge flow of the slag S _l has a horizontal velocity, but falls following the parabolic trajectory, the reasons described above, the horizontal reach is the width direction center of the discharge flow of the slag S _l It tends to be large at the portion and relatively small at the end portion in the width direction of the discharge flow.

Further, in the intermediate Haikasu process, discharge of slag S _l is performed in a state where blocking door 32 is closed. At this time, the slag S ₁ discharged from the furnace port 21 is applied to the shut-off door 32. From the characteristics of the shape of the discharge flow of the slag S ₁ as described above, the shut-off door of the discharge flow of the slag S ₁ is used. 32 (including the protective plates 323a and 323b), the width of the collision position (the length in the x-axis direction) is qualitative as the distance between the furnace body 2 and the furnace floor 5 or the second distance L increases. Tend to become narrower.

Furthermore, when the discharge speed of the slag S _l is high to some extent, the discharge flow of the slag S _l that collides with the blocking door 32 flows down while spreading the surface of the blocking door 32 in the width direction (x-axis direction). The height of the collision position of the slag discharge flow with the shut-off door 32 in the z-axis direction is the distance between the furnace body 2 and the furnace front floor 5 from the parabolic trajectory of the falling discharge flow, or the above-mentioned second height. The distance L tends to decrease as the distance L increases. Therefore, slug S _l discharge flow spreads in the longitudinal width direction when flowing down the surface of the blocking doors 32 (x-axis direction) also becomes smaller tendency in accordance with the second distance L increases.

The influence of the distance between the furnace body 2 and the furnace front floor 5 or the second distance L on the width of the slag S ₁ discharged from the furnace port 21 on the surface of the shut-off door 32 is qualitative as described above. Can be explained. Furthermore, the present inventors have found that the slag S _l dividing by dimensionless index at a radius r [m] of the throat a maximum width take the surface of the blocking doors 32, and the second distance L [m] by organizing using dimensionless index by dividing the rotation axis center to the furnace opening 21 at a height H [m] of the furnace body 2 of the trunnion 22, the width of the slag S _l according to the blocking doors 32 It was found that it can be quantitatively evaluated. That is, the present inventors have assumed that x _sm [m] is a half of the maximum width (that is, the width in the x-axis direction from the center position P _c of the furnace port) on which the slag S _{1 on} the surface of the blocking door 32 is applied. As described later, it was found that x _sm / r <1-3 L / H.

Accordingly, the first distance d in the x-axis direction between the center position P _c of召合blocking door 32 allowed positions P _a and throat 21 [m] is greater than 0, and not meet the above formula (1) lever, the distance d is to become a value larger than x _sm, does not take slag S _l discharged into召合allowed position P _a. Therefore, it is possible to suppress the adhesion of slag S _l to召合allowed position P _a. Intermediate Haikasu step, after a predetermined amount of slag S _l is discharged, terminated by erecting the furnace body 2. The portion of the door 32 where the slag S _l facing the furnace port 21 is provided with a cooling member such as a water-cooled steel pipe, so that even if the slag S _l adheres, it easily peels off and is disposed under the furnace. Since it falls into the container, it does not require extra work time to remove the fallen objects.

Thereafter, as shown in FIG. 6 (D), as in the primary acid refining step, oxygen gas is blown from the acid feed lance 7 and oxygen gas is supplied to the hot metal M to remove phosphorus (dephosphorization P blowing). (Secondary acid refining process). At this time, the dephosphorization process is performed in a state where the blocking door 32 is closed. In the secondary oxygen-flow refining process, lime medium solvents, and various order to facilitate adjustment and slag formation of the components of the slag S _l optionally auxiliary material is added to the interior of the furnace body 2. The dephosphorization process is completed by blowing a predetermined amount of oxygen gas determined according to the phosphorus concentration of the hot metal M, the hot metal amount, the temperature, the slag component, and the like.

Next, as shown in FIG. 6 (E), the furnace body 2 is tilted so that the furnace port 21 is located on the hot water side opposite to the front side of the furnace, and the hot water outlet hole 24 provided on the furnace back side of the furnace body 2. The hot metal M that has been dephosphorized is discharged (hot water) from the hot water (heated out process). The discharged hot metal M is accommodated in a hot metal pan (not shown) disposed below the furnace body 2. The tapping process, the molten iron M after pouring, when the slag S _l after dephosphorization in the oxygen-flow-refining of the next molten iron to be described later is required, the slag S _l after dephosphorization within the interior of the furnace body 2 The process ends with the remaining state. On the other hand, if not necessary slag S _l after dephosphorization in the oxygen-flow-refining of the next hot metal treatment by slag S _l after dephosphorization is discharged to the outside of the furnace is completed. In the hot water discharge process, when the hot metal M is discharged and when the slag _Sl is discharged, the blocking door 32 continues to be closed.

The molten metal M is continuously desiliconized and dephosphorized by performing a series of processes including the charging process, the desiliconization process, the intermediate waste process, the dephosphorization process and the hot water process. In the present embodiment, after the series of oxygen-flow refining is performed, in the same converter-type smelting furnace 1, to open the shut-off doors 32, the series was charged scrap S _c and subsequent hot metal The acid feeding smelting is repeated. In this case, at desiliconization step, when the slag S _l generated in the secondary oxygen-flow refining step prior to the oxygen-flow-refining used, occurred in the secondary oxygen-flow refining process inside the furnace 2 in a state in which slag S _l is remaining, charging step is performed in the oxygen-flow-refining of the next hot metal.

<Modification>
Although the present invention has been described above with reference to specific embodiments, it is not intended that the present invention be limited by these descriptions. From the description of the invention, other embodiments of the invention will be apparent to persons skilled in the art, along with various variations of the disclosed embodiments. Therefore, it is to be understood that the claims encompass these modifications and embodiments that fall within the scope and spirit of the present invention.

For example, in the above embodiment, for召合allowed position P _a is the center position P _c of the furnace opening 21, although a are shifted in the x-axis negative direction, the present invention is not limited to such an example. For example,召合allowed position P _a is with respect to the center position P _c of the throat 21 may be offset in the x-axis positive direction.
In the above embodiment, as shown in FIG. 1, it is preferable that the length of the width W1 is 1.25 times or more and 4.0 times or less of the length of the width W2. It is not limited to. Blocking door 32 is in the closed state, covers the furnace front opening 311, a first distance d between the center position P _c of召合allowed positions P _a and throat 21 is larger than 0 m, and (1) The widths W1 and W2 are not limited to the above ranges as long as they satisfy the above requirements. In addition, by setting the widths W1 and W2 in the above range, in the general converter-type refining furnace 1, the value d / r of the ratio of the first distance d to the radius r in the present invention is 0.2 or more. The embodiment to be applied can be applied, and the entire width of the blocking door 32 can be reduced. Further, by setting the length of the width W1 to 1.8 times or more of the length of the width W2, in a general converter-type refining furnace 1, the ratio of the first distance d to the radius r in the present invention is An embodiment in which the value d / r is 0.86 or more can be applied, and the entire width of the blocking door 32 can be reduced. The furnace body shape of the converter-type refining furnace 1 is substantially similar, and the ratio r / H between the radius r of the furnace port and the height H from the center of the trunnion to the furnace port is 0.3 to 0. Generally, it is in the range of .5. When the length of the width W1 is less than 1.25 times the length of the width W2, the dimensions of the converter-type refining furnace 1 (the width of the front opening side of the furnace, the size of the furnace port, and the overall width of the shut-off door 32) ) May cause the first distance d to be smaller than 0.2 times the radius r of the furnace port 21. On the other hand, when the length of the width W1 is more than 4.0 times the length of the width W2, the dimensions of the converter-type refining furnace 1 (the width of the open portion on the front side of the furnace, the size of the furnace port, and the entire shut door 32) Depending on the width of the first door portion, the width W1 of the first door portion becomes too long, which may increase the time required to open and close the blocking door 32.

Furthermore, in the said embodiment, although it was set as the refining form which performs a desiliconization process in a primary acid refining process, and performs a dephosphorization process in a secondary acid refining process, this invention is not limited to this example. For example, a refining configuration in which desiliconization treatment is performed in the primary acid refining process, dephosphorization and decarburization processes are performed in the secondary acid refining process, and desiliconization and dephosphorization processes are performed in the primary acid refining process. A refining form in which the decarburizing process is performed in the acid refining process, or a refining form in which the dephosphorizing process is performed in the secondary acid refining process and the decarburizing process is performed in the secondary acid refining process. Incidentally, and the amount of Hiyatetsugen S _c and slag S _l housed in the furnace in the charging step, the amount of discharging the slag S _l in the intermediate Haikasu step out of the furnace, the furnace body 2 in the tapping step two various operating conditions such as the amount to residual slag S _l after the next oxygen-flow refining process, according to the above refining embodiments, refining efficiency and refining costs are appropriately set so as to minimize. For example, the refining form in which desiliconization treatment is performed in the primary acid refining process and dephosphorization and decarburization processes are performed in the secondary acid refining process, when the silicon content of the hot metal M is high, or silicon is added as a combustion heat source When a large amount of scrap is melted, the desulfurization reaction is advanced simultaneously with the desiliconization treatment. Therefore, in view of resulfurization prevention from dephosphorization and decarburization slag composition control and the slag S _l in the process, it is necessary to particularly reduce the residual amount of slag from intermediate Haikasu.

<Effect of embodiment>
(1) The shut-off door 32 of the converter-type refining furnace 1 according to one aspect of the present invention includes a first moving means 321a that can move in a uniaxial direction (x-axis direction) parallel to the horizontal direction, and one end in the uniaxial direction. It has a first summing unit 322a on the side, and can cover a part of the furnace front side open part 311 of the fixed wall 31 which is a part of the partition wall 3 surrounding the furnace body 2 of the converter type refining furnace 1 The first door portion 32a, the second door 321b arranged in a uniaxial direction with the first door portion 32a and movable in the uniaxial direction, and the uniaxial direction facing the first door portion 32a It has a second summoning section 322b on one end side, and a second door section 32b that can partially cover the furnace front side opening section 311. The first summing section 322a and the second summoning section 322b are provided. The mating portion 322b is combined, and the first door portion 32a and the second door portion 32b close the furnace front side open portion 311. In state, parallel to the uniaxial direction of the first convene mating portion 322a and the dressing alignment P _a is the second convene mating portion 322b and is mated position, the center position P _c of the furnace opening 21 furnace body 2 The first distance d [m] in the direction is greater than 0 m, the radius r [m] of the furnace port 21, and the position where the furnace body 2 is tilted 90 degrees from the upright state to the side of the hot water. The relationship between the second distance L [m] between the furnace port 21 and the furnace front floor 5 and the height H [m] from the rotation axis center of the trunnion 22 of the furnace body 2 to the furnace port 21 is expressed by the equation (1). Meet.

According to the above configuration (1), by shifting the召合allowed position P _a from the center position P _c of the throat 21, when performing an intermediate Haikasu in the converter type refining furnace 1, the召合allowed position P _a It is possible to prevent the discharged slag _{Sl from} being applied. Therefore, it is possible to suppress the inflow and deposition of召合allowed position P _a and slag S _l of the lower furnace to the forehearth 5 of the blocking doors 32. For this reason, it is possible to prevent the blocking door from functioning due to the deposits attached to the summing portion of the blocking door, and further, it is not necessary to remove the deposits, thereby improving productivity. Further, according to the configuration of (1) above, the time required for opening and closing the door can be shortened by making the blocking door 32 double-opening as compared with a single-opening blocking door consisting of a single door. And productivity can be improved. When the first distance d (1) is not satisfied equation, when the intermediate Haikasu while being forming slag S _l, in a region from the throat 21 there is a possibility that slag S _l flows out, since convene alignment P _a is to be positioned, and the prevention of adhesion of slag S _l to convene mating portion, it is difficult to achieve both an increase in the discharge rate of slag S _l, increase productivity The effect cannot be obtained sufficiently.

(2) In the configuration of (1) above, the value d / r of the ratio of the first distance d to the radius r is 0.2 or more.
(3) In the configuration of (2) above, the value d / r of the ratio of the first distance d to the radius r is 0.86 or more.
(4) In the above configuration (3), in the closed state, calling aligned P _a is, in a direction parallel to the uniaxial direction, distribution as the first distance d is longer than the radius r of the furnace opening 21 Is done.

According to the above configuration (2) to (4), when performing intermediate Haikasu, that召合allowed slag S _l, which is discharged to position P _a is applied, can be more reliably prevented.
(5) In the configuration of any of (2) to (4) above, the uniaxial width W1 of the first door portion 32a is 1.25 times or more the uniaxial width W2 of the second door portion 32b. 4.0 times or less.
According to the configuration of the above (5), it can be applied to a general converter type refining furnace 1.

(6) The method of operating the converter type refining furnace 1 according to one aspect of the present invention is to supply oxygen gas to the hot metal M accommodated in the furnace body 2 of the converter type refining furnace 1 and send the hot metal M to the acid refining process. After the primary acid refining process and the primary refining process, the furnace body 2 is positioned so that the furnace port 21 of the furnace body 2 is located on the front side of the furnace body 2 while the hot metal M accommodated in the furnace body 2 remains in the furnace body 2. 2, and an intermediate waste process for discharging at least a part of the slag S ₁ generated in the primary acid refining process from the furnace port 21, and a hot metal left in the furnace body 2 after the intermediate waste process And a secondary acid refining process for supplying oxygen gas to M and further refining the acid, and in the intermediate waste process, a first moving means movable in a uniaxial direction (x-axis direction) parallel to the horizontal direction 321a and a first summing portion 322a on one end side in the uniaxial direction, and the front side of the fixed wall 31 that is a part of the partition wall 3 surrounding the furnace body 2 A first door portion 32a capable of covering a part of the opening 311; a second moving means 321b arranged in a uniaxial direction with the first door portion 32a and movable in the uniaxial direction; The second summit portion 322b is provided at one end in the uniaxial direction facing the first door portion 32a, and the second door portion 32b capable of covering a part of the furnace front side open portion 311 is provided. The blocking door 32 is closed with the first summing portion 322a and the second summing portion 322b being combined, and the first door portion 32a and the second door portion 32b covering the furnace front side opening portion 311. state, to discharge the slag S _l from the furnace outlet 21, in the closed state, and calling aligned P _a is a position where the first convene mating portion 322a and the second convene mating portion 322b come together, the furnace 2 the first distance d in the direction parallel to the axial direction of the center position P _c of the throat 21 [m] , The radius r [m] of the furnace port 21 and the position of the furnace port 21 and the furnace floor 5 at the position where the furnace body 2 is tilted 90 degrees from the upright state to the side of the hot water. The relationship between the distance L [m] of 2 and the height H [m] from the rotation axis center of the trunnion 22 of the furnace body 2 to the furnace port 21 satisfies the expression (1).

According to the configuration of the above (6), the same effect as the above (1) can be obtained. Further, in the intermediate Haikasu step, it is necessary to shorten the time required for the intermediate Haikasu process and thus increase the discharge rate of slag S _l, and slag S _l can take a large amount by the blocking doors 32 Become. However, according to the above configuration (6), in the intermediate Haikasu process, even when freshly slag S _l to the blocking door 32, since the slag S _l does not take into召合allowed position P _c, slag S _l The discharge speed can be increased, and the time required for intermediate waste can be shortened. For this reason, the productivity in the converter type refining furnace can be improved, and the amount of hot metal for performing the hot metal pretreatment and the production amount of molten steel can be increased.

Next, examples performed by the present inventors will be described. In the embodiment, using a plurality of converter-type refining furnaces 1 having different ratios L / H of the second distance L to the height H, the hot metal M is acid-refined and the shut-off door 32 at the time of intermediate discharge is obtained. The state of adhesion of slag _{Sl to} the surface was confirmed.
First, as charged step, it was charged with hot metal M, which is tapped from the blast furnace body 2, which had been pre-charged with Hiyatetsugen S _c.

Next, the shut-off door 32 was closed, and desiliconization treatment was performed as a primary acid refining process. In the primary acid feed refining process, oxygen gas was supplied from the acid feed lance 7 to the hot metal M, and stirring gas was blown into the hot metal M from the bottom blowing nozzle 23. Further, in the primary oxygen-flow refining process, intermediate Haikasu discharging slag of the slag S _l in the process in order to increase (dischargeability), slag S _l basicity (weight of CaO with respect to SiO ₂ in the slag S _l% Ratio) is adjusted to a range of 0.8 to 1.3, and the acid feed speed and lance height from the acid feed lance 7 (height from the bath surface of the molten iron M to the lower end of the acid feed lance 7) are adjusted. by the iron oxide content in the slag S _l after the primary oxygen-flow refining by to the operating conditions such that 10 to 30 mass%, was forming a slag S _l.

Further, as an intermediate Haikasu step is tilting to furnace opening 21 furnace body 2 to the furnace front is located, it drained slag S _l in the furnace from the throat 21. In the intermediate Haikasu step, the intermediate Haikasu was performed in a state where召合allowed position P _a closed blocking door 32 apart by a first distance d from the center position P _c of the furnace opening 21 in the x-axis direction. The discharged slag S ₁ was accommodated in a hot metal container disposed below the furnace body 2.
Thereafter, dephosphorization treatment was performed as a secondary acid refining process. In the primary acid feed refining process, oxygen gas was supplied from the acid feed lance 7 to the hot metal M, and stirring gas was blown into the hot metal M from the bottom blowing nozzle 23.
Next, as a hot water discharge step, the furnace body 2 was tilted so that the furnace port 21 was positioned on the front side of the furnace, and the hot metal M subjected to the dephosphorization treatment was discharged from the hot water discharge hole 24.

FIG. 7 shows the results of the example. The graph shown in FIG. 7 is a plot in which the horizontal axis is the ratio value L / H of the second distance L to the height H, and the vertical axis is the ratio value d / r of the first distance d to the radius r. , indicating the presence or absence of adhesion of slag S _l to convene alignment P _a blocking doors 32 in each condition. In the embodiment, it is determined whether or not there is slag S ₁ adhesion under each d / r condition from the presence or absence of slag S ₁ adhesion in the x-axis direction of the blocking door 32 under each L / H condition. did. As shown in FIG. 7, the slag S ₁ is attached in a region where d / r <1-3 L / H, the first distance d having a solid line A as a threshold is greater than 0 m, and (1) with the condition that satisfies the equation, that slag S _l is not applied and it was confirmed to召合allowed position P _a blocking door 32. Further, as shown by broken lines B and C in FIG. 7, in addition to the condition of the first distance d described above, the d / r is set to 0.2 or more, and further to 0.86 or more, thereby more reliably blocking. to be able to suppress the adhesion of slag S _l to召合allowed position P _a of the door 32 has been confirmed.

Further, in the embodiment, actually arranged convene alignment P _a of the above embodiments and blocked similarly door 32, to confirm the presence or absence of adhesion of slag S _l to召合allowed position P _a blocking door 32. The plot of the condition shown in FIG. 7 where L / H is 0.25 and d / r is 0.43, and the plot of the condition where L / H is 0.15 and d / r is 1 are shown in the above embodiment. and the condition is arranged by shifting the convene alignment P _a blocking door 32 as well. Under the former condition, the width ratio W1 / W2 of the blocking door was about 1.5, and under the latter condition, the width ratio W1 / W2 of the blocking door was about 2.3. Under these conditions, the intermediate Haikasu step, discharged slag S _l is never applied to the positions P _a was召合, it is possible to increase the discharge speed of slug S _l, the center position召合allowed position P _a is It was confirmed that the time required for the intermediate evacuation process can be shortened compared with the shut-off door at _Pc . Further, after the intermediate Haikasu, convene mating portion 322a of the blocking doors 32, the召合allowed position _{P a} of 322b and furnace forehearth 5, it was confirmed that there are no deposits, such as slag _{S l.}
From the above results, according to the present invention, the converter type refining furnace 1 for intermediate Haikasu, it was confirmed that it is possible to suppress the adhesion of slag S _l to召合allowed position P _a.

DESCRIPTION OF SYMBOLS 1 Converter type refining furnace 2 Furnace body 21 Furnace port 22 Trunnion 23 Bottom blowing nozzle 24 Hot water outlet 3 Bulkhead
31 Fixed wall 311 Opening part on the furnace front side 32 Shut-off door 32a First door part 321a First moving means 322a First summing part 323a First protective plate 32b Second door part 321b Second moving means 322b Second 2 summoning section 323b 2nd protective plate 4 dust collecting equipment 41 skirt 42 hood 5 furnace front floor 6 hot metal ladle 7 acid lance W1, W2 (of shut-off door) width P _a summing position P _c (furnace entrance ) Center position r Radius of furnace opening d First distance L Second distance H Height from trunnion rotation axis center to furnace opening M Hot metal S _l Slag S _c Scrap

Claims (6)

Part of a partition wall having a first moving means movable in a uniaxial direction parallel to a horizontal direction and a first summing portion on one end side in the uniaxial direction and surrounding a furnace body of a converter type refining furnace A first door part capable of covering a part of the furnace front side opening part of the fixed wall,
A second moving means arranged side by side in the uniaxial direction with the first door portion and movable in the uniaxial direction, and a second sump on one end side in the uniaxial direction facing the first door portion. And a second door portion that can partially cover the furnace front side open portion,
In the closed state where the first summoning unit and the second summoning unit are combined, and the first door portion and the second door portion cover the furnace front side open portion, A first distance d [m] in a direction parallel to the uniaxial direction between a summing position where one summing part and the second summing part meet and a center position of a furnace port of the furnace body. ] Is larger than 0 m, the radius r [m] of the furnace port, and the furnace port and the floor in front of the furnace at a position where the furnace body is tilted 90 degrees from the upright state to the counter hot water side. The converter type refining characterized in that the relationship between the second distance L [m] and the height H [m] from the center of the rotation axis of the trunnion of the furnace body to the furnace port satisfies the equation (1). The furnace door.
d / r ≧ 1-3 L / H (1)   2. The conversion door of the converter type refining furnace according to claim 1, wherein a value d / r of a ratio of the first distance d to the radius r is 0.2 or more.   The value d / r of the ratio of the first distance d to the radius r is 0.86 or more, and the converter type refining furnace shut-off door according to claim 2.   The said summing position in the said closed state is distribute | arranged so that the said 1st distance d may become longer than the said radius r in the direction parallel to the said uniaxial direction. Shutter door of the converter type smelting furnace.   The width in the uniaxial direction of the first door part is 1.25 times or more and 4.0 times or less than the width in the uniaxial direction of the second door part. A shut-off door of the converter type refining furnace according to any one of the above items. A primary acid refining process in which oxygen gas is supplied to the hot metal contained in the furnace body of the converter-type refining furnace, and the hot metal is acid-refined,
After the primary acid refining process, the furnace body is tilted so that the furnace port of the furnace body is located on the front side of the furnace while the hot metal contained in the furnace body remains in the furnace body. An intermediate waste process for discharging at least a part of the slag generated in the primary acid refining process from the furnace port;
A secondary acid refining process for supplying the oxygen gas to the molten iron remaining in the furnace body after the intermediate waste process and further refining the acid.
The intermediate evacuation step includes a first moving means that is movable in a uniaxial direction parallel to a horizontal direction and a first summing portion on one end side in the uniaxial direction, and a partition wall that surrounds the furnace body. A first door part capable of covering a part of the furnace front side opening part of the fixed wall, which is a part, and a first door part arranged side by side in the uniaxial direction and movable in the uniaxial direction. And a second summing portion on one end side in the uniaxial direction opposite to the first door portion, and is capable of covering a part of the furnace front side opening portion. A shut-off door provided with a door portion is formed by combining the first summing portion and the second summing portion, and the first door portion and the second door portion allow the front opening portion of the furnace to be opened. With the covered closed state, the slag is discharged from the furnace port,
In the closed state, a direction parallel to the uniaxial direction between a summing position where the first summing part and the second summing part are combined with a center position of the furnace port of the furnace body The first distance d [m] is greater than 0 m, and the radius r [m] of the furnace port, the position at which the furnace body is tilted 90 degrees from the upright state to the side of the hot water. The relationship between the second distance L [m] between the furnace port and the front floor of the furnace and the height H [m] from the rotation axis center of the trunnion of the furnace body to the furnace port satisfies the equation (1). A method of operating a converter-type smelting furnace characterized by
d / r ≧ 1-3 L / H (1)

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