Slag discharging method for converter-type refining furnace and operation method of converter

Abstract

To accurately estimate the shape of a refining furnace and accurately control the tilt angle of the refining furnace.SOLUTION: A method for discharging slag from a converter type refining furnace in an intermediate discharging step of the converter type refining furnace 1 includes a step of estimating the shape of a refractory 10 lined inside the refining furnace 1 by referring to a wear database based on the operating conditions of the refining furnace 1 and the number of times the refining furnace 1 is used, and a step of controlling the tilt angle of the refining furnace 1 based on the estimated shape of the refractory 10 and discharging at least a part of slag 2 from the refining furnace 1. The wear database is a database constructed based on the measured shape of the refractory 10.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a slag discharging method for a converter-type refining furnace and an operation method for a converter.

Background Art

[0002] In recent years, the required quality of steel materials has become increasingly strict, and reduction of impurity elements such as silicon and phosphorus has been demanded. In order to meet such requirements, in the steelmaking process of a steelworks, pretreatment is generally carried out at the stage of hot metal, and silicon, phosphorus, etc. in the hot metal are removed to some extent.

[0003] As part of the steelmaking process, in a converter-type refining furnace, after performing a desiliconization treatment on the hot metal in the refining furnace, at least a part of the slag generated by the desiliconization treatment is discharged by tilting the refining furnace. This process is also referred to as an intermediate slag discharging process. Note that the slag generated by the desiliconization treatment is also referred to as "desiliconization slag".

[0004] After the intermediate slag discharging process, a dephosphorization treatment is performed. The dephosphorization treatment is a treatment in which a CaO (calcium oxide)-based solvent is introduced into the refining furnace to dephosphorize the hot metal remaining in the refining furnace.

[0005] In the operation of a converter, in a slag discharging process such as the intermediate slag discharging process, an important point is how quickly a large amount of slag can be discharged from the refining furnace.

[0006] In order to increase the discharge amount of desiliconization slag in the intermediate slag discharging process, it is conceivable to increase the tilting angle of the refining furnace when discharging the desiliconization slag. However, if the tilting angle is increased too much, the hot metal will also be discharged from the furnace mouth of the refining furnace together with the desiliconization slag. In that case, the iron yield will decrease, so it is necessary to accurately control the tilting angle so as not to increase the tilting angle too much.

[0007] Even if the amount of desiliconized slag after the desiliconization treatment is the same, the molten metal level of the desiliconized slag will be at different heights depending on the shape of the refining furnace. For example, when the wear of the refractory lining inside the refining furnace progresses, the molten metal level of the desiliconized slag will be low, and when the wear of the refractory does not progress, the molten metal level of the desiliconized slag will be high. Since the molten metal level of the desiliconized slag depends on the shape of the refining furnace in this way, the amount of desiliconized slag discharged when the refining furnace is tilted depends on the shape of the refining furnace. Therefore, when discharging the desiliconized slag from the refining furnace, it is desirable to accurately control the tilting angle according to the shape of the refining furnace.

[0008] For example, Patent Document 1 and Patent Document 2 disclose a technique for correcting the tilting angle of a refining furnace according to the number of times of use of a converter.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0010] The refractory lining inside the refining furnace wears out as the number of times of use of the refining furnace increases.

[0011] However, how the refractory of the refining furnace wears does not solely depend on the number of times of use of the refining furnace. For example, how the refractory wears depends on the furnace lining thickness. Also, the refractory does not wear uniformly in all parts, and wears at different rates depending on the part.

[0012] Since Patent Document 1 and Patent Document 2 only consider the number of times of use of the converter, they cannot consider the influence of the furnace lining thickness and the influence of the part.

[0013] An object of the present disclosure is to provide a slag discharging method for a converter-type refining furnace and an operation method for a converter that can accurately estimate the shape of the refining furnace and accurately control the tilting angle of the refining furnace.

Means for Solving the Problems

[0014] [1] A slag discharging method for a converter-type refining furnace, comprising: estimating the shape of the refractory lining inside the refining furnace by referring to a wear database based on the operating conditions of the refining furnace and the number of times the refining furnace has been used; controlling the tilting angle of the refining furnace based on the estimated shape of the refractory, and discharging at least a part of the slag from the refining furnace; wherein the wear database is a database constructed based on the actually measured shape of the refractory. A slag discharging method for a converter-type refining furnace.

[0015] [2] The slag discharging method for a converter-type refining furnace according to [1] above, wherein the wear database is a database constructed based on the shape inside the furnace and / or the shape of the furnace mouth of the refining furnace.

[0016] [3] The slag discharging method for a converter-type refining furnace according to [1] or [2] above, wherein the wear database is a database constructed based on the shape of the refractory measured two or more times in situations with different numbers of uses and the operating conditions therebetween.

[0017] [4] The slag discharging method for a converter-type refining furnace according to any one of [1] to [3] above, wherein the frequency of measuring the shape of the refractory is higher for measuring the shape of the furnace mouth than for measuring the shape inside the furnace.

[0018] [5] The operation conditions include at least one of the blowing form, the temperature history in the refining furnace, the amount of hot metal in the refining furnace, the amount of oxygen introduced into the refining furnace, and the shape of the top blowing lance, and are the slag discharging method for the converter-type refining furnace according to any one of the above [1] to [4].

[0019] [6] The in-furnace shape of the refractory measured when constructing the loss database is measured by performing profile measurement with a distance meter installed in front of the furnace mouth of the refining furnace, and is the slag discharging method for the converter-type refining furnace according to any one of the above [1] to [5].

[0020] [7] The furnace mouth shape of the refractory measured when constructing the loss database is measured by performing profile measurement based on an image obtained by an imaging device installed in front of the furnace mouth of the refining furnace, and is the slag discharging method for the converter-type refining furnace according to any one of the above [1] to [6].

[0021] [8] A desiliconization treatment step of subjecting the hot metal tapped from the blast furnace to desiliconization treatment; An intermediate slag discharging step of discharging at least a part of the slag generated in the desiliconization treatment step while leaving the desiliconized hot metal in the refining furnace; A dephosphorization treatment step of subjecting the hot metal left in the refining furnace in the intermediate slag discharging step to dephosphorization treatment; A tapping step of tapping the dephosphorized hot metal from the refining furnace; and is an operation method of a converter, comprising: The intermediate slag discharging step executes the slag discharging method for the converter-type refining furnace according to any one of the above [1] to [7], and is an operation method of a converter.

Advantages of the Invention

[0022] According to the slag discharging method for the converter-type refining furnace and the operation method of the converter according to the present disclosure, it is possible to accurately estimate the shape of the refining furnace and accurately control the tilting angle of the refining furnace.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 3C

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0024] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0025] The slag discharging method of the converter-type refining furnace according to the present embodiment (hereinafter, may be simply referred to as "the slag discharging method according to the present embodiment") is a method of discharging slag from the converter-type refining furnace.

[0026] FIG. 1 is a diagram schematically showing the intermediate slag discharging process of a converter-type refining furnace.

[0027] The refining furnace 1 is a converter-type refining furnace. When a desiliconization treatment process is performed on the hot metal 3 in the refining furnace 1, slag 2 is generated. The slag 2 is also referred to as "desiliconization slag".

[0028] In the desiliconization treatment step, an oxygen-containing gas is supplied from an upper blowing lance to the hot metal 3 in the refining furnace 1. When the oxygen-containing gas supplied from the upper blowing lance reacts with the carbon in the hot metal 3, CO gas is generated.

[0029] The slag 2 after the desiliconization treatment step contains the CO gas bubbles generated in this way. The apparent volume of the slag 2 increases several times or more by containing the CO gas bubbles. Such a state is also referred to as a "forming state".

[0030] The slag discharging method according to the present embodiment can discharge at least a part of the slag 2 from the refining furnace 1 by tilting the refining furnace 1 while controlling the tilting angle of the refining furnace 1.

[0031] Referring to FIG. 2, the tilting angle of the refining furnace 1 will be described. The tilting angle of the refining furnace 1 is represented by how many degrees the horizontal line 102 of the refining furnace 1 has rotated with respect to the horizontal line 101. In FIG. 2, the angle θ indicates the tilting angle of the refining furnace 1.

[0032] Returning to FIG. 1 again, the description will be continued.

[0033] After the desiliconization treatment step, when the refining furnace 1 is tilted as shown in FIG. 1, the slag 2 is discharged from the furnace mouth of the refining furnace 1 to the slag ladle 4. The slag 2 discharged into the slag ladle 4 is transported by the slag bogie 5.

[0034] As shown in FIG. 3A, a refractory 10 is lined inside the refining furnace 1. The refractory 10 is worn out by repeated blowing in the refining furnace 1. That is, the wear of the refractory 10 increases as the number of times the refining furnace 1 is used increases.

[0035] Referring to FIGS. 3A to 3C, the state in which the shape of the refining furnace 1 changes due to the wear of the refractory 10 will be described.

[0036] FIG. 3A is a diagram schematically showing the shape of the refractory 10 when the number of times the refining furnace 1 is used is 0, that is, when the refining furnace 1 is unused.

[0037] Figure 3B is a diagram schematically showing the shape of the refractory 10 when the number of times the refining furnace 1 is used is 307 times. Note that the reference numeral 11 shown by the dashed line indicates the shape of the refractory 10 when the refining furnace 1 is not in use. As shown in Figure 3B, the shape of the refractory 10 has changed from the shape of the refractory 10 shown in Figure 3A due to progressive wear.

[0038] Figure 3C is a diagram schematically showing the shape of the refractory 10 when the number of times the refining furnace 1 is used is 4023 times. Note that the reference numeral 11 shown by the dashed line indicates the shape of the refractory 10 when the refining furnace 1 is not in use. As shown in Figure 3C, the shape of the refractory 10 has further changed from the shape of the refractory 10 shown in Figure 3B due to further progressive wear.

[0039] Note that, as shown in Figures 3B and 3C, the wear of the refractory 10 does not progress uniformly in all parts, but progresses at different rates depending on the part. Therefore, as shown in Figures 3B and 3C, the shape of the refractory 10 becomes a shape in which wear progresses non-uniformly depending on the part.

[0040] How the wear of the refractory 10 of the refining furnace 1 progresses varies depending on the furnace lining replacement. Also, how the wear of the refractory 10 of the refining furnace 1 progresses varies depending on the operating conditions of the refining furnace 1.

[0041] The slag discharge method according to the present embodiment estimates the shape of the refractory 10 lined inside the refining furnace 1 by referring to the wear database based on the operating conditions of the refining furnace 1 and the number of times the refining furnace 1 is used.

[0042] The wear database will be described. The wear database is a database for estimating the shape of the refractory 10 of the refining furnace 1 based on the operating conditions of the refining furnace 1 and the number of times the refining furnace 1 is used. The wear database correlates the operating conditions of the refining furnace 1 with the wear rate for each part of the refractory 10 of the refining furnace 1.

[0043] The loss database is constructed based on the measured shape of the refractory 10. Fig. 4 schematically shows how to measure the shape of the refractory 10 in the refining furnace 1.

[0044] As shown in Fig. 4, the shape of the refractory 10 in the refining furnace 1 can be measured by the distance meter 6. The distance meter 6 may be a non-contact type distance meter. The distance meter 6 may be installed on the tripod 7.

[0045] The shape of the refractory 10 in the refining furnace 1 can be measured after the treatment in the refining furnace 1 is completed. When measuring the shape of the refractory 10 in the refining furnace 1, tapping of the hot metal 3 and discharge of the slag 2 are performed before the measurement. Also, the refining furnace 1 is tilted so that the furnace mouth faces the distance meter 6. Thereby, the distance meter 6 installed in front of the furnace mouth of the refining furnace 1 can measure the inside of the furnace of the refining furnace 1 from the furnace mouth.

[0046] The distance meter 6 performs profile measurement of the refractory 10 in the refining furnace 1 in a state where the furnace mouth of the refining furnace 1 is tilted so as to face the distance meter 6. Profile measurement means measuring the distance to each part of the refractory 10 in the refining furnace 1. By performing profile measurement, the distance meter 6 can measure the loss state of the refractory 10 at each part.

[0047] If such profile measurement is carried out for each charge, the shape of the refractory in the refining furnace 1 can be grasped for each charge. However, it takes time to perform profile measurement of the refractory 10 by the above procedure. Since it affects the operation of the refining furnace 1, it is not realistic to perform profile measurement for each charge.

[0048] Therefore, in the slag removal method according to the present embodiment, a loss database is constructed based on profile measurements performed several times on the refining furnace 1, and the shape of the refractory 10 is estimated based on the constructed loss database.

[0049] In addition, the shape of the refractory 10 in the refining furnace 1 can also be measured by replacing the distance meter 6 with the imaging device 8. The imaging device 8 performs profile measurement of the furnace mouth shape by image processing in a state where the furnace mouth of the refining furnace 1 is tilted so as to face the imaging device 8, and the shape of the refractory at the furnace mouth can be grasped from the positional relationship between the imaging device 8 and the furnace mouth. The measurement of the furnace mouth shape of the refining furnace 1 by the imaging device 8 does not take as much measurement time as the measurement of the furnace interior shape by the distance meter 6. Therefore, the frequency of measuring the shape of the refractory to construct the wear database can be increased more for the measurement of the furnace mouth shape than the number of times of measuring the furnace interior shape.

[0050] The wear database may be constructed based on the measurement results of the distance meter 6 for the furnace interior shape and the measurement results of the imaging device 8 for the furnace mouth shape. In this way, the wear database may be constructed based on the furnace interior shape of the refining furnace 1 and / or the furnace mouth shape of the refining furnace 1.

[0051] The wear database is constructed based on the shape of the refractory 10 measured two or more times in situations where the number of uses of the refining furnace 1 is different and the operating conditions during that period.

[0052] For example, when two profile measurements are performed on the same refining furnace 1 in situations where the number of uses of the refining furnace 1 is different, the shape of the refractory 10 will be different in each profile measurement. From the difference in the shape of the refractory 10 between these two measurements, the wear rate [mm / charge] of the refractory 10 at each part can be calculated.

[0053] In addition, how the refractory 10 wears also depends on the operating conditions of the refining furnace 1.

[0054] For example, depending on whether the blowing mode is desiliconization blowing or decarburization blowing, the temperature history in the refining furnace 1 and the amount of oxygen introduced into the refining furnace 1 will be different. Then, the shape of the refractory 10 in the refining furnace 1 will proceed in different manners depending on whether the blowing mode is desiliconization blowing or decarburization blowing.

[0055] As described above, since how the refractory 10 wears depends on the operating conditions of the refining furnace 1, the wear database is constructed based on the shape of the refractory 10 measured two or more times in situations with different numbers of uses and the operating conditions during that time.

[0056] The operating conditions include at least one of the blowing mode, the temperature history in the refining furnace 1, the amount of hot metal in the refining furnace 1, the amount of oxygen input into the refining furnace 1, and the shape of the top-blowing lance.

[0057] As an example of the wear rate depending on the operating conditions, FIG. 5 shows the relationship between the oxygen supply rate and the wear rate. Note that FIG. 5 shows data for two different refractories 10, namely refractory A and refractory B.

[0058] The horizontal axis of FIG. 5 is the average oxygen supply rate when oxygen is input into the refining furnace 1, which is the value obtained by dividing the amount of oxygen input into the refining furnace 1 by the blowing time. The vertical axis of FIG. 5 is the wear rate at a certain part of the refining furnace 1.

[0059] As shown in FIG. 5, the wear rates of refractory A and refractory B depend on the oxygen supply rate, which is an operating condition.

[0060] Also, as shown in FIG. 5, different refractories 10, namely refractory A and refractory B, have different wear rates. This indicates that the wear rate depends on the furnace lining replacement.

[0061] The slag discharge method according to this embodiment includes a step of estimating the shape of the refractory 10 lined inside the refining furnace 1 by referring to the wear database based on the operating conditions of the refining furnace 1 and the number of uses of the refining furnace 1.

[0062] The step of estimating the shape of the refractory 10 reads the wear rate corresponding to the current operating conditions of the refining furnace 1 for each part of the refining furnace 1 by referring to the wear database. Then, the step of estimating the shape of the refractory 10 estimates the shape for each part of the refining furnace 1, that is, for each position of the refractory 10, based on the wear rate and the number of uses of the refining furnace 1.

[0063] Thus, the slag discharging method according to this embodiment estimates the shape of the refractory 10 lined inside the refining furnace 1 by referring to the wear database based on the operating conditions of the refining furnace 1 and the number of times the refining furnace 1 has been used.

[0064] Further, when the slag discharging method according to this embodiment estimates the shape of the refractory 10, it controls the tilting angle of the refining furnace 1 based on the estimated shape of the refractory 10, and discharges at least a part of the slag 2 from the refining furnace 1.

[0065] Here, the wear database is a database constructed based on the actually measured shape of the refractory 10.

[0066] Thus, the slag discharging method according to this embodiment estimates the shape of the refractory 10 lined inside the refining furnace 1 by referring to the wear database constructed based on the actually measured shape of the refractory 10, based on the operating conditions of the refining furnace 1 and the number of times the refining furnace 1 has been used. Therefore, the slag discharging method according to this embodiment can accurately estimate the shape of the refractory 10, that is, the shape of the refining furnace 1. Further, since the slag discharging method according to this embodiment controls the tilting angle of the refining furnace 1 based on the shape of the refractory 10 accurately estimated in this way, the tilting angle of the refining furnace 1 can be accurately controlled. Therefore, the slag discharging method according to this embodiment can quickly discharge a large amount of the slag 2 from the refining furnace 1 without reducing the iron yield.

[0067] Since the slag discharging method according to this embodiment estimates the shape of the refractory 10 for each part, the tilting angle of the refining furnace 1 can be accurately controlled according to which part is worn. For example, the shape of the refractory 10 near the furnace mouth of the refining furnace 1 has a great influence on the discharge of the slag 2, but the slag discharging method according to this embodiment can control the tilting angle of the refining furnace 1 in consideration of the shape of the refractory 10 near the furnace mouth.

[0068] In addition, since the slag removal method according to the present embodiment estimates the shape of the refractory 10 using a database constructed based on the actually measured shape of the refractory 10, the shape of the current refractory 10 can be estimated based on the shape of the refractory 10 measured when the number of uses is relatively close. Therefore, the slag removal method according to the present embodiment can accurately estimate the shape of the refractory 10 even when the number of uses of the refining furnace 1 increases.

[0069] The operation method of the converter using the refining furnace 1 will be described. Here, the operation of the converter refers to the entire process performed by the converter, including slag removal processes such as the intermediate slag removal process.

[0070] The operation method of the converter according to the present embodiment includes a desiliconization treatment step of desiliconizing the hot metal 3 tapped from the blast furnace, and an intermediate slag removal step of discharging at least a part of the slag 2 generated in the desiliconization treatment step while leaving the desiliconized hot metal 3 in the refining furnace 1, a dephosphorization treatment step of dephosphorizing the hot metal 3 remaining in the refining furnace 1 in the intermediate slag removal step, and a tapping step of tapping the dephosphorized hot metal 3 from the refining furnace 1.

[0071] In the operation method of the converter according to the present embodiment, the intermediate slag removal step may execute the slag removal method of the converter-type refining furnace according to the present embodiment.

[0072] (Example 1) FIG. 6 shows an example when the shape of the refractory 10 is estimated by the slag removal method according to the present embodiment.

[0073] FIG. 6 is a graph when the shape of the refractory 10 is estimated when the refining furnace 1 is used 2749 times. In FIG. 6, the vertical axis represents the slag volume. The slag volume is the slag volume when the height of the slag in the refining furnace 1 is 5 m. The slag volume is correlated with the shape of the refractory 10. When it is estimated that the loss of the refractory 10 is large, the slag volume becomes large, and when it is estimated that the loss of the refractory 10 is small, the slag volume becomes small.

[0074] Comparative Example 1 estimated the shape of the refractory 10 assuming that the refractory 10 uniformly wore out from when the number of uses of the refining furnace 1 was 0 to when it was 2749 times. Comparative Example 2 measured the shape of the refractory 10 when the number of uses of the refining furnace 1 reached 1844 times, and estimated the shape of the refractory 10 assuming that the refractory 10 uniformly wore out from the shape at the 1844 - time stage to when it was 2749 times.

[0075] In the Example, the shape of the refractory 10 was measured when the number of uses of the refining furnace 1 reached 1844 times, and the change in the shape of the refractory 10 from the shape at the 1844 - time stage to when it was 2749 times was estimated by the step of estimating the shape of the refractory 10 according to the present embodiment.

[0076] Also, FIG. 6 shows, as measured values, the result of calculating the slag volume by measuring the profile of the shape of the refractory 10 in the refining furnace 1 when the number of uses of the refining furnace 1 is 2749 times.

[0077] Referring to FIG. 6, in Comparative Example 1 and Comparative Example 2, the slag volume is significantly larger compared to the measured values. This means that the wear of the refractory 10 was over - estimated.

[0078] In contrast, in the Example, the value of the slag volume is almost equal to the measured value. This shows that according to the present embodiment, the wear of the refractory 10 can be accurately estimated.

[0079] Note that FIG. 6 compares the situation when the number of uses of the refining furnace 1 is 2749 times, but comparisons at other numbers of uses and comparisons at other furnace generations were also made. In that case, when using the estimation methods such as Comparative Example 1 and Comparative Example 2, there were cases where the wear of the refractory 10 was underestimated. Therefore, when estimating assuming that the refractory 10 uniformly wears out as in the Comparative Examples, there are cases of over - estimating and under - estimating the wear of the refractory 10, and it was difficult to accurately estimate the wear of the refractory 10 with the estimation methods such as Comparative Example 1 and Comparative Example 2.

[0080] Figure 7 shows an example when the intermediate slag discharge process is carried out by the slag discharge method according to this embodiment.

[0081] Figure 7 compares the case where the intermediate slag discharge process is carried out by the method according to the comparative example and the case where the intermediate slag discharge process is carried out by the slag discharge method according to this embodiment using a 300-ton refining furnace 1 with 100 channels.

[0082] The vertical axis in Figure 7 is the average value of the intermediate slag discharge rate. The intermediate slag discharge rate indicates the ratio of the weight of the slag 2 discharged from the refining furnace 1 by the intermediate slag discharge process to the weight of the slag 2 before the intermediate slag discharge process.

[0083] The weight of the slag 2 before the intermediate slag discharge process was calculated using a blowing model. Also, the weight of the slag 2 discharged from the refining furnace 1 by the intermediate slag discharge process was measured by a load cell type weighing device installed on the slag transfer trolley 5 that transports the discharged slag 2. At this time, pretreatment such as air bagging was performed on the slag transfer pot 4 on the slag transfer trolley 5, and the weight of the discharged slag 2 was obtained from the weight after the discharge of the slag 2 was completed.

[0084] The comparative example shown in Figure 7 is the result when the intermediate slag discharge process was carried out by estimating the shape of the refractory 10 assuming that the refractory 10 uniformly wears from the time when the number of uses of the refining furnace 1 is 0 times.

[0085] As shown in Figure 7, in the comparative example, the intermediate slag discharge rate is about 45%, whereas in the example according to this embodiment, the intermediate slag discharge rate was about 64%. Thus, the example according to this embodiment can improve the intermediate slag discharge rate compared to the comparative example.

[0086] (Example 2) Fig. 8 shows the intermediate slag discharge rate when the measurement frequency of the furnace mouth shape is increased. In the comparative example, it is estimated as uniform wear, whereas in this example, the measurement of the furnace body shape was carried out at a frequency of once every 1500 times, and the measurement of the furnace mouth shape was carried out at a frequency of once every 10 times. As a result, it becomes possible to quickly grasp the shape change of the furnace mouth. In the example according to this embodiment, the intermediate slag discharge rate was about 76%. Thus, by increasing the measurement frequency of the furnace mouth shape, it becomes possible to precisely predict the shape of the refractory and to significantly improve the intermediate slag discharge rate.

[0087] The present disclosure is not limited to the above-described embodiments. For example, a plurality of blocks described in the block diagram may be integrated, or one block may be divided. Instead of executing a plurality of steps described in the flowchart in time series according to the description, they may be executed in parallel or in a different order according to the processing capacity of the device that executes each step or as necessary. In addition, changes can be made without departing from the spirit of the present disclosure.

[0088] For example, in the above-described embodiment, the case where the slag discharge method according to this embodiment is implemented in the intermediate slag discharge process of the converter-type refining furnace 1 was taken as an example for explanation. However, the slag discharge method according to this embodiment can also be implemented in slag discharge processes other than the intermediate slag discharge process. For example, the slag discharge method according to this embodiment can also be implemented in the process of discharging slag after decarburization blowing. Further, the slag discharge method according to this embodiment can also be implemented other than the converter-type refining furnace 1. For example, the slag discharge method according to this embodiment can also be implemented in the steelmaking process in an electric furnace. Also, for example, the slag discharge method according to this embodiment can also be implemented in the refining process in non-ferrous metal smelting such as copper refining.

Explanation of Reference Numerals

[0089] 1 Refining furnace 2 Slag 3 Hot metal 4 Slag ladle 5 Slag ladle car 6 Rangefinder 7 Tripod 8 Imaging device 10 Refractory 11 Shape of the refractory when not in use 101 Horizontal line 102 Horizontal line of the refining furnace

Claims

1. A method for discharging slag from a converter-type refining furnace, comprising: estimating the shape of the refractory lining inside the refining furnace by referring to a wear database based on the operating conditions of the refining furnace and the number of times the refining furnace has been used; controlling the tilting angle of the refining furnace based on the estimated shape of the refractory, and discharging at least a part of the slag from the refining furnace; and the wear database is a database constructed based on the actually measured shape of the refractory; the wear database is a database constructed based on the shape inside the furnace and / or the shape of the furnace mouth of the refining furnace; In order to construct the wear database, the frequency of measuring the shape of the refractory is higher for measuring the shape of the furnace mouth than for measuring the shape inside the furnace, a method for discharging slag from a converter-type refining furnace.

2. The wear database is a database constructed based on the shape of the refractory measured two or more times in situations with different numbers of uses and the operating conditions during that period, the method for discharging slag from a converter-type refining furnace according to Claim 1.

3. The operating conditions include at least one of the blowing mode, the temperature history inside the refining furnace, the amount of hot metal in the refining furnace, the amount of oxygen input into the refining furnace, and the shape of the top-blown lance, the method for discharging slag from a converter-type refining furnace according to Claim 1.

4. The shape inside the furnace of the refractory measured when constructing the wear database is measured by performing profile measurement with a distance meter installed in front of the furnace mouth of the refining furnace, the method for discharging slag from a converter-type refining furnace according to Claim 3.

5. The shape of the furnace mouth of the refractory measured when constructing the wear database is measured by performing profile measurement with an image obtained by an imaging device installed in front of the furnace mouth of the refining furnace, the method for discharging slag from a converter-type refining furnace according to Claim 3.

6. A desiliconization treatment step of subjecting hot metal tapped from a blast furnace to desiliconization treatment; An intermediate slag discharge step of discharging at least a part of the slag generated in the desiliconization treatment step from the refining furnace while leaving the desiliconized hot metal in the refining furnace; A dephosphorization treatment step of subjecting the hot metal left in the refining furnace in the intermediate slag discharge step to dephosphorization treatment; A tapping step of tapping the dephosphorized hot metal from the refining furnace; which is an operation method of a converter, comprising: The intermediate slag discharge step performs the slag discharge method of the converter type refining furnace according to any one of claims 1 to 5. An operation method of a converter.

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