JP6547815B2 - Operation method of converter type smelting furnace - Google Patents

Description

  The present invention relates to a method of operating a converter-type smelting furnace.

  The tapping hole of the converter type smelting furnace is a hole for separating the molten steel or hot metal after the smelting process from the slag and discharging it from the furnace (also referred to as “hot water”). Or a solidified refractory material. The refractory proceeds with erosion when exposed to high temperature and high flow rate molten steel and hot metal. For this reason, in the converter-type smelting furnace, the inner diameter of the tapping hole is expanded as the number of tappings increases.

  In the case of a converter-type smelting furnace used as a decarburizing furnace (also referred to as a "converter") for steelmaking to carry out a decarburizing treatment, the inside diameter of the tapping hole is expanded to usually add the alloy to the tapping. If this is done, there arises a problem that the dissolution time of the added alloyed iron can not be secured. Further, in this case, if the inner diameter of the tapping hole is enlarged, the slag is likely to flow out at the time of tapping, which causes problems in quality or components due to the inclusion of the slag. For this reason, according to the meltdown condition of a tapping hole, repair of a tapping hole and replacement | exchange of a sleeve brick are performed suitably. Furthermore, in this case, if the inside diameter of the tapping hole is too small, the tapping time becomes too long, which causes a problem of a drop in productivity and a drop in molten steel temperature. From these things, the initial internal diameter of the tapping hole is selected in accordance with the purpose in consideration of the above-mentioned factors.

  In addition, in the case of a converter-type smelting furnace used as a pre-treatment furnace which performs at least one of desiliconization treatment and dephosphorization treatment of molten iron, the addition time of alloyed iron is not usually added to the hot water, so the dissolution time of alloyed iron is There is no need to secure. Also, in this case, the influence of the inclusion of slag on the quality and components is smaller than that of the decarburization treatment. For this reason, the inside diameter of the tapping hole is generally selected to be larger than that of the decarburizing furnace. However, the excessive expansion of the inside diameter of the tapping hole due to the melting failure causes the equipment trouble due to the scattering of the tapping flow. For this reason, also in this case, it is necessary to repair the hot water outlet and replace the sleeve brick according to the melting condition.

  In a steelmaking plant of a steelmaking plant, after performing pre-treatments such as desiliconization treatment, dephosphorization treatment, and desulfurization treatment to the molten metal discharged from the blast furnace, by performing decarburization treatment, the amount of impurity components is small, carbon A low concentration of molten steel is produced. For this reason, in recent years, a plurality of converter-type smelting furnaces provided in one steelmaking plant are divided into a decarburizing furnace and a pre-treatment furnace, and are prepared separately for molten iron in different converter-type smelting furnaces. An operation in which the treatment and the decarburization treatment are sequentially performed is widely performed.

  Here, the wear rate of the inner refractory of the converter-type smelting furnace is higher in the case of using as a decarburizing furnace having a high smelting temperature than in the case of using as a pre-processing furnace. For this reason, when using a plurality of converter-type smelting furnaces of the same type separately for the pre-processing furnace and the decarburizing furnace, generally, after lining bricks of the converter-type smelting furnace are newly constructed, The converter type smelting furnace is used as a decarburizing furnace, and the converter type smelting furnace is used as a pre-treatment furnace in the latter half of the furnace cost when the residual thickness of the inner refractory is reduced. That is, in a steelmaking plant, the application is switched from decarburizing furnace use to pretreatment furnace operation in the middle of the furnace cost of the converter type smelting furnace so as to balance the planned number of times of use as a decarburization furnace and pretreatment furnace. It is common to do. If the thickness of the inner refractory line can not be secured even as a pre-treatment furnace, a major repair is performed, in which the entire inner refractory line of the converter-type smelting furnace is newly replaced. During this major repair, the number of converter-type smelting furnaces that can be used will be reduced by one, so if there is no room in the number of converter-type smelting furnaces, pretreatment of hot metal by the converter-type smelting furnace is carried out. In addition, the converter-type smelting furnace is used only as a decarburizing furnace.

  Pretreatments such as desiliconization treatment and dephosphorization treatment can be performed as backup also in other hot metal pretreatment facilities, or although refining costs increase, they can be performed simultaneously with decarburization treatment in a decarburization furnace. On the other hand, decarburization can be processed only in a converter-type smelting furnace for decarburizing furnace. Therefore, if the decarburization furnace suddenly becomes inoperable due to a problem etc., the converter-type smelting furnace used as the hot metal pre-treatment furnace is provisionally used as the decarburization furnace as a backup. Temporary measures are taken.

As described above, when changing the converter type smelting furnace from the pre-treatment furnace to the decarburizing furnace in the middle of the furnace cost, it is necessary to change the hole diameter of the tapping hole as described below. The hole diameter of the tapping hole can be changed by applying the sleeve brick replacement method.
As a method of replacing the sleeve brick of the steel outlet hole (spout hole) of the converter conventionally proposed, for example, the sleeve brick to be replaced is removed by drilling, a new sleeve brick is inserted, and fire resistance around the steel outlet hole There is a method of pouring an unshaped refractory material into a gap between an object and a sleeve brick and solidifying it (see, for example, Patent Document 1).

Also, as another method of removing the sleeve brick to be replaced, the takeout rod is inserted into the steel tapping hole, the hook at the tip of the takeoff rod is hooked on the furnace inner end of the sleeve brick and pulled out outwards A method for taking it out (see, for example, Patent Document 2) has been proposed. Furthermore, in order to facilitate the insertion of the repair sleeve brick into the melted steel tapping hole, the metal or slag adhering to the furnace inner wall near the furnace inner end of the steel tapping hole or the steel tapping hole is a lance pipe A method of melting and removing by injecting oxygen gas from the above (see, for example, Patent Document 3) has been proposed.
On the other hand, as a simple repair method of the steel-out hole which omitted the above-mentioned sleeve brick removal, in addition to the method of applying a baking material etc. directly to a melted part, a repair pipe is inserted in the steel-out hole and There is a method (see, for example, Patent Document 4) in which the space is filled with a monolithic refractory.

Japanese Patent Application Laid-Open No. 63-235419 JP-A-5-195038 JP-A-5-117738 JP, 2011-179040, A

  By the way, in the technique mentioned by patent document 1, although the fused unnecessary refractory was removed by perforation | piercing, it was a subject that this operation requires time for alignment at the time of perforation | piercing and perforation | piercing itself. When the time taken for the drilling operation is long, in addition to the decrease in productivity, since the operation is under high heat, the workload of the worker is also increased. Further, although the techniques described in Patent Literatures 2 and 3 can omit the drilling operation described in Patent Literature 1, the removal of the refractory and the metal itself is necessary, so the task time is increased. there were. Furthermore, in the technique described in Patent Document 4, although the work time can be shortened since the removal work of the refractory etc. is unnecessary, the service life is about 15 charge for simple repair using an unshaped refractories to the last And short was a problem.

  Therefore, the present invention has been made focusing on the above-mentioned problems, and when changing the inside diameter of the tapping hole of the converter-type smelting furnace to a smaller size, the time for the work of changing can be shortened. The object is to provide a method of operating a converter-type smelting furnace capable of securing the life.

  According to one aspect of the present invention, there is provided a method of operating a converter-type smelting furnace having a tapping hole formed of a sleeve brick for lining, wherein the converter is reduced when reducing the inside diameter of the tapping hole. A second lining sleeve brick having an outer diameter smaller than the inner diameter of the first lining sleeve brick without using the first lining sleeve brick provided in the mold smelting furnace; A method of operating a converter-type smelting furnace is provided, which is characterized in that it is inserted and fixed inside the first lining sleeve brick.

  According to one aspect of the present invention, there is provided a method of operating a converter-type smelting furnace having a tapping hole formed of a sleeve brick for lining, wherein the hot metal is subjected to at least one of silicon removal treatment and phosphorus removal treatment. When the converter-type smelting furnace provided with the first lining sleeve brick for forming the hot-water outlet hole for use as a decarburizing furnace for decarburizing the molten iron to make molten steel, A second lining sleeve brick having an outer diameter smaller than the initial inner diameter of the first lining sleeve brick without using the first lining sleeve brick from the furnace type smelting furnace, A method of operating a converter-type smelting furnace is provided, wherein the inner diameter of the tapping hole is reduced by inserting and fixing the first lining sleeve brick inside.

  According to one aspect of the present invention, there is provided a method of operating a converter-type smelting furnace for melting molten steel from molten metal using a plurality of converter-type smelting furnaces, wherein the converter-type smelting furnace is The plurality of converter-type smelting furnaces described above are used as a pre-treatment furnace for subjecting the hot metal to a dephosphorization treatment after being used as a decarburizing furnace for subjecting the hot metal to a decarburizing treatment to obtain a molten steel. And the decarburizing furnace, and after dephosphorizing the hot metal using the pretreating furnace, using the decarburizing furnace which is a converter-type smelting furnace different from the pretreating furnace. The molten steel is melted by subjecting the molten metal subjected to the phosphorus removal treatment to the above-mentioned decarburization treatment, and when the converter type smelting furnace used as the above-mentioned decarburization furnace becomes inoperable, as the above-mentioned pre-treatment furnace With regard to the converter-type refining furnace used, the above-mentioned No. 1 lining sleeve brick that forms the tapping hole is not removed. Of the outlet hole by inserting and fixing a second lining sleeve brick whose outer diameter is smaller than the initial inner diameter of the lining sleeve brick at the time of not being used inside the first lining sleeve brick. There is provided a method of operating a converter-type smelting furnace characterized by making a change to reduce the inner diameter and using it as the decarburizing furnace.

  According to one aspect of the present invention, when changing the inside diameter of the tapping hole of the converter type smelting furnace to a smaller size, the time required for the work of the change can be shortened, and the converter type can ensure the useful life. The operation method of the smelting furnace is provided.

It is sectional drawing which shows a converter type refinement furnace. It is a fragmentary sectional view which shows the tapping hole vicinity of a converter type refinement furnace. It is a fragmentary sectional view showing the state before changing the inside diameter of the tapping hole of one embodiment of the present invention. It is a fragmentary sectional view showing the state where the second sleeve sleeve for lining was inserted in the method of changing the inside diameter of the tapping hole. It is a fragmentary sectional view which shows the state which fixed the 2nd sleeve brick for linings in the method of changing the internal diameter of a tapping hole. It is a graph which shows the relationship between the number of times of the pouring hole and tapping time in an Example.

In the following detailed description, numerous specific details are set forth by way of illustrating embodiments of the present invention in order to provide a thorough understanding of the present invention. However, it will be apparent that one or more embodiments may be practiced without such specific details. Also, in the drawings, well-known structures and devices are schematically illustrated for the sake of simplicity.
<Operation method of converter type smelting furnace>
In the operation method of the converter-type smelting furnace according to one embodiment of the present invention, the smelting process is performed using the converter-type smelting furnace 1 shown in FIG. The converter type smelting furnace 1 is a smelting vessel whose upper end is opened, and includes a furnace shell 2 and a lining brick 3 lined inside the furnace shell 2. Further, on the upper side surface of the converter type smelting furnace 1, a tapping hole 10 is formed which is formed to penetrate from the inside to the outside of the converter type smelting furnace 1 and for discharging the molten iron or molten steel. The outlet hole 10 is one of the lining bricks 3 and is a hole formed by the lining sleeve brick 4 which is a hollow cylindrical shaped refractory.

  In such a converter-type smelting furnace 1, the molten iron to be subjected to the refining process is charged from a furnace port which is an opening formed in the upper part. Then, oxygen is blown into the molten metal in the converter-type smelting furnace 1 from an upper-blowing lance (not shown) disposed above the molten metal, thereby performing oxidation and refining of the molten metal. In many steel mills, a plurality of converter-type smelting furnaces 1 are provided in a steelmaking plant, and in recent years, each converter-type smelting furnace 1 has individual treatment such as pretreatment and decarburization treatment from the viewpoint of smelting efficiency and cost. The operation method is to be taken to operate with the function. In this case, the hot metal to be refined is pretreated in a pretreating furnace and then decarburized in a decarburizing furnace which is a converter-type smelting furnace different from the pretreating furnace to become molten steel.

  Here, the pretreatment in the present embodiment is at least one of a desiliconization treatment and a dephosphorization treatment. The desiliconization treatment and the dephosphorization treatment are treatments for oxidizing and removing silicon and phosphorus in the hot metal to reduce the silicon content and the phosphorus content of the hot metal. The decarburizing treatment is a treatment to reduce the carbon content of the hot metal to oxidize it by oxidizing and removing carbon in the hot metal. When oxidizing and refining molten metal, basically, silicon is preferentially oxidized compared to carbon, and the lower the temperature of molten metal is, the more advantageous it is for phosphorus oxidation, so after pre-treatment is performed Decarburization processing will be performed.

  Further, as described above, the inner diameter d of the tapping hole is larger in the case of being used as a pretreatment furnace than in the case of being used as a decarburizing furnace. Therefore, the lining sleeve brick 4 provided in the converter-type smelting furnace 1 usually used as a decarburizing furnace and the lining sleeve brick 4 provided in the converter-type smelting furnace 1 used as a pretreatment furnace The same size of the outer diameter D but different in size of the inner diameter d is used.

  In the present embodiment, molten steel is melted using a plurality of converter-type smelting furnaces 1 provided in a steelmaking plant. The converter type smelting furnace 1 is basically used as a decarburizing furnace in the first half (first half) during one furnace cost and as a pre-treatment furnace in the second half (second half). The converter type smelting furnace 1 is used for smelting processing until a lining brick is newly constructed and installed, and the remaining thickness of the lining brick becomes thin enough to be unusable. And when the remaining thickness of the lining brick becomes thin, the remaining lining brick is removed and a new lining brick is constructed, and it is used for refinement processing again. In the operation method of the converter-type smelting furnace 1 according to the present embodiment, the construction of the lining brick and the use for the refining process are repeatedly performed on the converter-type smelting furnace 1. The number of times that lining bricks are newly installed in the converter type smelting furnace 1 is called furnace cost. That is, after the lining bricks are newly constructed in the converter type smelting furnace 1, the remaining thickness of the lining bricks becomes thin and the converter type smelting furnace 1 can not be used for the smelting process between 1 furnace cost. Between.

  Furthermore, in the present embodiment, the plurality of converter-type smelting furnaces 1 in the steelmaking plant are divided into a pre-processing furnace and a decarburizing furnace to smelt molten steel. For example, when there are three converter-type smelting furnaces 1 in a steelmaking plant, one may be used as a pre-treatment furnace and the remaining two may be used as a decarburizing furnace. Moreover, since it takes time to construct the lining bricks of the converter type smelting furnace 1, one of the three converter type smelting furnaces 1 is used as a pre-treatment furnace, and the other is used as a decarburizing furnace. The remaining one may be paused for construction of lining bricks. Further, from the viewpoint of productivity, it is preferable to always have a pretreatment furnace and a decarburization furnace in a steelmaking plant. In other words, the timing of the change from the decarburization furnace to the pretreatment furnace, the timing of the renewal of the furnace cost of the converter-type smelting furnace, and the like are performed so that the pretreatment furnace and the decarburization furnace exist simultaneously.

  When a plurality of converter-type smelting furnaces 1 are divided into a pre-processing furnace and a decarburizing furnace for operation, at least one converter-type smelting furnace 1 is unexpectedly Production capacity will drop significantly. Under the present circumstances, when the converter type refinement furnace 1 which became inoperable is used as a pre-processing furnace, the measure which performs pre-processing with other pre-processing equipment, pre-processing and de-carbonization with a decarburization furnace Measures are taken either to do both charcoal treatment or to omit pre-treatment. On the other hand, when the converter type smelting furnace 1 which has become inoperable is used as a decarburizing furnace, the converter type smelting furnace 1 used as a preliminary treatment furnace is provisionally used as a decarburizing furnace It is necessary to take temporary measures. In this case, as described above, the size of the inner diameter d of the tapping hole 10 is different between the preliminary treatment furnace and the decarburizing furnace, and it is possible to apply the large pouring hole 10 of the inner diameter d in the preliminary treatment furnace to the decarburizing furnace Because it is not possible, a change is made to reduce the inner diameter d.

In the present embodiment, in the operation method of the converter type refining furnace 1, the reduction of the inner diameter d of the tapping hole 10 is accompanied by the change from the pretreatment furnace of the converter type refining furnace 1 to the decarburizing reactor. Do. When the converter type smelting furnace 1 is used as a pre-processing furnace, as shown in FIG. 3, a first lining sleeve brick 4A is provided at a location corresponding to the tapping hole 10 of the lining brick 3 There is. The first lining sleeve bricks 4A is similar to the sleeve bricks provided in a conventional pretreatment furnace outer diameter D ₁ and the initial inner diameter d _{1 '.} Initial inner diameter d _{1 'is} the inner diameter d ₁ of the first lining sleeve bricks 4A unused (when new). In the state shown in FIG. 3, after the first lining sleeve brick 4A is provided, the hot metal pre-treatment is performed at least once. The inner diameter d ₁ is larger than the initial inner diameter d ₁ ′.

In the change of the inner diameter d of the tapping hole 10 in the present embodiment, first, as shown in FIG. 4 with respect to the converter type refining furnace 1 used as the pre-processing furnace shown in FIG. The second lining sleeve brick 4B is inserted inside the sleeve brick 4A. Second lining sleeve bricks 4B is a first lining sleeve bricks 4A and cylindrical monolithic refractories Similarly, the outer diameter D ₂ is the initial inner diameter d _{1 'of} the first lining sleeve bricks 4A Too small. The inner diameter d ₂ of the second lining sleeve bricks 4B may inner diameter normally used in decarburization furnace, less than the initial inner diameter d _{1 'of} the first lining sleeve bricks 4A. Furthermore, to be able to insert the second lining sleeve bricks 4B without alignment precise location, the difference from the initial inner diameter d _{1 'minus} the outer diameter D ₂ is more preferably set to 20mm or more.

Then, as shown in FIG. 5, after inserting the second lining sleeve brick 4B, the monolithic refractory 5 is placed in the gap between the first lining sleeve brick 4A and the second lining sleeve brick 4B. The body is poured from the inside of the furnace in a state where the body is turned to the hot water side, and the monolithic refractory 5 is dried and solidified to fix the second lining sleeve brick 4B to the first lining sleeve brick 4A. As a method of fixing the second lining sleeve brick 4B, for example, a method similar to the method described in Patent Document 1 may be used, and the first lining sleeve brick 4A and the second lining sleeve brick 4B are used. The monolithic refractory 5 may be injected from the inside of the converter-type smelting furnace 1 into the gap between them. Further, before pouring the monolithic refractory 5 from the inside of the converter type smelting furnace 1, the monolithic refractory is sprayed to the outside of the converter type smelting furnace 1 to make the second lining sleeve brick 4B a first lining. It may be temporarily fixed to sleeve brick 4A.
Through the above process, the inner diameter of the tapping hole 10 is changed from the inner diameter d ₁ for preliminary processing on the inner diameter d ₂ for decarburization.

<Modification>
While the invention has been described with reference to particular embodiments, the description is not intended to limit the invention. Other embodiments of the present invention, including various modifications, as well as the disclosed embodiments, will be apparent to those of ordinary skill in the art by reference to the description of the present invention. Therefore, it is to be understood that the embodiments of the invention described in the claims also encompass the embodiments including the variants described above alone or in combination.

For example, although the said embodiment demonstrated the time of changing the converter type smelting furnace 1 from a pre-processing furnace to a decarburizing furnace, this invention is not limited to this example. Even in a decarburizing furnace, the inner diameter d of the tapping hole 10 may be changed depending on the type of steel to be melted. For example, it is sometimes necessary to suppress the outflow of slag at the time of tapping of hot water after decarburization treatment in a strict steel type that is strict in quality such that the upper limit of the content of the target impurity component is low. For this reason, in such a strict steel type, it is preferable to make the inside diameter d of the tapping hole 10 smaller than that of a general steel type which is a general quality. In particular, in a steelmaking factory where there are many types of steels to be melted, a general decarburizing type and a strict type of steel may be continuously melted in one decarburizing furnace. That is, in the converter type smelting furnace 1 used as the decarburizing furnace, the same change method as described above can be used when changing the melting target from a general steel type to a strict steel type. In this case, the inside diameter d1 of the _first lining sleeve brick 4A is set to be suitable for melting of a general steel grade, and the inside diameter d2 of the _second lining sleeve brick 4B is a strict grade steel It is set to one suitable for melting.

  Moreover, although the said embodiment demonstrated the case where the converter type refinement furnace 1 used as a pre-processing furnace was changed so that it could be used as a decarburization furnace, this invention is not limited to this example. For example, the method of changing the inner diameter d in the above embodiment is also applied to a case where the pretreatment furnace before use provided with the first lining sleeve brick 4A can be used as a decarburizing furnace in a limited manner. can do.

<Effect of the embodiment>
(1) The operation method of the converter-type refining furnace 1 according to one aspect of the present invention is an operation method of the converter-type refining furnace 1 having the tapping hole 10 formed of the lining sleeve brick 4, When making a change to reduce the inner diameter d of 10, without removing the first lining sleeve brick 4A provided in the converter type smelting furnace 1, the first lining sleeve brick 4A is not in use. the second lining sleeve brick 4B outer diameter D ₂ is smaller than the inner diameter (the initial inner diameter d ₁ '), inserting and fixing the inner side of the first lining sleeve bricks 4A.

  According to the configuration of (1), when reducing the inner diameter d of the tapping hole 10, the second lining sleeve brick 4B is provided without removing the used first lining sleeve brick 4A. For this reason, as compared with the method of providing a new lining sleeve brick after removing the refractory including the melted lining sleeve brick by drilling as in Patent Document 1, it is required for alignment at the time of drilling and drilling itself. The work time can be reduced by the time. Also, as compared with the method of taking out and cleaning the used lining sleeve brick as in Patent Document 2 and providing a new lining sleeve brick, the working time is reduced by the time required to take out the lining sleeve brick. can do.

  Moreover, in the configuration of the above (1), the first lining sleeve brick 4A and the second lining sleeve brick 4B are fixed refractories. Therefore, when the first lining sleeve brick 4A and the second lining sleeve brick 4B are fixed with the monolithic refractory 5, the first lining sleeve brick 4A and the second lining sleeve brick are used. The converter-type smelting furnace 1 can be used only by drying and solidifying a small amount of the monolithic refractory 5 provided in the gap with 4B. That is, since the use amount of the monolithic refractory is large, it is possible to perform the change work in a short time as compared with Patent Documents 1 and 4 in which the time required for drying and solidification is long.

Furthermore, according to the configuration of the above (1), the outer diameter D2 of the _second lining sleeve brick 4B is made smaller than the inner diameter d1 of the _first lining sleeve brick 4A when not in use. The second lining sleeve brick 4B can be provided regardless of the number of times of use and remaining thickness of the existing first lining sleeve brick 4A. For this reason, since the removal process of a residual refractory material can be skipped, working time can be shortened.

  Thus, since the operation rate of the converter-type smelting furnace 1 is improved by shortening the working time, productivity can be improved. Moreover, the operation | work which concerns on perforations, such as position alignment and perforation | piercing in patent document 1, and the removal operation | work of a residual refractory and a metal base become the operation | work under high heat. However, according to the configuration of the above (1), since these operations can be omitted, the workload of the worker can be reduced.

  Furthermore, according to the structure of said (1), the outlet hole 10 after a change is formed by the 2nd sleeve brick 4B for linings which is a highly durable shaped refractory. For this reason, compared with the case where a tapping hole is formed with a monolithic refractory as in Patent Document 4, the service life can be improved, and the refractory cost can be suppressed. The thickness of the second lining sleeve brick 4B in the configuration of the above (1) is thinner than in the case where the tapping hole 10 is formed by one thick lining sleeve brick 4. For this reason, the service life will be reduced compared to the case of changing using the methods of Patent Documents 1 to 3. However, in the case where a preliminary treatment furnace is provisionally used as a decarburization furnace, or in the case where a high grade steel is melted in a limited manner while melting a general steel, there is sufficient service life.

(2) The operation method of the converter-type refining furnace 1 according to one aspect of the present invention is the operation method of the converter-type refining furnace 1 having the tapping hole 10 formed of the lining sleeve brick 4 The converter-type refining furnace 1 equipped with the first lining sleeve brick 4A for forming the tapping hole for the pre-treatment furnace which performs at least one of the desiliconization treatment and the dephosphorization treatment is subjected to decarburization treatment to the molten iron When used as a decarburizing furnace for making molten steel, without removing the first lining sleeve brick 4A from the converter type smelting furnace 1, the initial inner diameter d of the first lining sleeve brick 4A when not used the second lining sleeve brick 4B outer diameter D ₂ is smaller than _{1 ',} by inserting and fixing the inner side of the first lining sleeve bricks 4A, a change to reduce the inner diameter d of the tapping hole 10 Do.

(3) The operation method of the converter-type refining furnace 1 according to an aspect of the present invention is an operation method of the converter-type refining furnace 1 in which molten steel is melted from molten metal using a plurality of converter-type refining furnaces 1 By using the converter type smelting furnace 1 as a decarburizing furnace for decarburizing the molten metal to make the molten steel for one furnace cost, and then using it as a pretreatment furnace for subjecting the molten metal to the dephosphorizing process A plurality of converter-type smelting furnaces 1 are divided into a pre-processing furnace and a decarburizing furnace, and after dephosphorizing the molten iron using the pre-processing furnace, a converter-type smelting furnace different from the pre-processing furnace By using a decarburization furnace which is 1 to decarburize the molten metal subjected to the dephosphorization treatment, the molten steel is melted and the converter type refining furnace 1 used as the decarburization furnace becomes inoperable In this case, for the pre-processing furnace used as a pre-processing furnace, the first lining sleeve brick 4A for forming the tapping hole was provided. The furnace-type smelting furnace 1, when used as a decarburization furnace, without removing the first lining sleeve bricks 4A, than the initial inner diameter d _{1 'when} unused first lining sleeve bricks 4A the second lining sleeve brick 4B outer diameter D ₂ is smaller, by inserting and fixing the inner side of the first lining sleeve bricks 4A, make changes to reduce the inner diameter d of the pouring hole 10, decarburization Used as a furnace.

  According to the configuration of the above (2) or (3), as in the configuration of the above (1), the change for reducing the inner diameter d of the tapping hole 10 can be performed in a short working time. For this reason, in the case where the plurality of converter-type smelting furnaces 1 are divided into a pre-processing furnace for pre-processing and a decarburizing furnace for decarburizing, the converter-type smelting furnace can not be operated suddenly Even in this case, the application of the pre-processing furnace to the decarburizing furnace can be changed in a short time, so that the occurrence of production loss can be suppressed. Moreover, the outlet hole 10 after a change will have a useful life sufficiently to be temporarily used as a decarburization furnace.

  An embodiment to which the present invention is applied will be described. In the example, using the method of changing the inner diameter d of the tapping hole 10 in the above embodiment, the pre-treatment furnace performing the dephosphorization treatment as the pre-treatment was changed to a decarburization furnace performing the decarburization treatment. In addition, as a converter type refinement furnace 1 used as a pre-processing furnace and a decarburization furnace, the thing of heat size (weight of the molten iron which can be processed) used 330ton.

In the example, first, the first lining sleeve brick 4A was provided on the lining brick 3 at the position of the tapping hole 10 of the converter-type refining furnace 1, and the preliminary treatment was performed. The first lining sleeve brick 4A has an initial inner diameter d ₁ ′ of 280 mm and a cylindrical sleeve with a length in the height direction of 1200 mm. The material of the first lining sleeve brick 4A is mag carbon brick of MgO = 89% and C = 8%.

Next, the second lining sleeve brick 4B is inserted into the existing first lining sleeve brick 4A from the outside of the furnace body with respect to the converter-type refining furnace 1 used as the preliminary treatment furnace, and the outside of the furnace body The second lining sleeve brick 4B was temporarily fixed by spraying a small amount of a monolithic refractory from the above. Second lining sleeve bricks. 4B, Example 1, the outer diameter _{D 2} is 250 mm, an inner diameter _{d 2} is 210 mm, those radial thickness of 20 mm, the outer diameter _{D 2} In Example 2 260 mm, inner diameter d ₂ is 210 mm, the thickness in the radial direction is used, respectively ones 25 mm. In addition, the sleeve length for lining, which is the length in the height direction of the cylindrical shape, is 1200 mm to 1400 mm, and depending on the remaining thickness of the refractory lining around the tapping hole of converter type smelting furnace 1, The length of the second lining sleeve brick 4B inserted is adjusted to the extent that it slightly protrudes to the inside of the furnace, and then inserted into the tapping hole 10 for temporary fastening. The material of the second lining sleeve brick 4B is the same as that of the first lining sleeve brick 4A.

Further, the monolithic refractory was poured and filled in the gap between the first lining sleeve brick 4A and the second lining sleeve brick 4B from the inside of the furnace body. Then, the change which reduces the internal diameter d of the tapping hole 10 was performed by hold | maintaining and filling the fixed-shaped refractory which was filled for a predetermined time.
In the embodiment, after reducing the inner diameter d of the tapping hole 10 in this manner, the converter type smelting furnace 1 is used as a decarburizing furnace, and the molten damage state of the tapping hole 10 is checked for the transition of tapping time. And the service life of the tapping hole 10 was confirmed. The useful life is the upper limit of the cumulative number of times of use of the hot water outlet 10 which can ensure the steel tapping time acceptable for the decarburizing furnace.

Moreover, in the Example, the reduction of the internal diameter d of the tapping hole 10 was performed also on two conditions of the following comparative examples 1 and 2 as a comparison, and the useful life of the tapping hole 10 after reduction was confirmed. First, in Comparative Example 1, in the same manner as in Patent Document 4, an indeterminate refractory is poured inside the first lining sleeve brick 4A in the converter-type refining furnace 1 similarly used as the pretreatment furnace. The inner diameter of the tapping hole 10 was reduced. Further, in Comparative Example 2, the first lining sleeve brick 4A is removed from the converter type smelting furnace 1 similarly used as the preliminary treatment furnace, and then the first lining sleeve brick 4A is removed. The inner diameter d of the tapping hole 10 is reduced by providing the lining sleeve brick 4 (the lining sleeve brick used in a general decarburizing furnace) having the same diameter D and a small inner diameter d. The inner diameter d of the tapping hole 10 immediately after reduction in order to be used as a decarburizing furnace in Comparative Examples 1 and ₂ is the same as the inner diameter d2 of the _second lining sleeve brick 4B in the example. did.

  In Table 1, as a result in Examples 1 and 2 and Comparative Examples 1 and 2, the time required for the change to reduce the inner diameter d by repairing and replacing the tapping hole 10, the service life of the tapping 10 after the change, and The types of the refractory forming the tapping hole 10 after the change are respectively shown. As shown in Table 1, in Example 1, it was found that the service life extended from 15 charges to 25 charges although the time required for repair / replacement was longer compared to Comparative Example 1. Further, Example 2 shows that the radial thickness of the second lining sleeve brick 4B is increased from 20 mm to 25 mm as compared to Example 1, and in this case, the service life is extended to 35 charges. The Moreover, in the Example, compared with the comparative example 2, it has confirmed that the time which repair and replacement require could be shortened about 30 minutes. Although the service life in the embodiment is shorter than that of Comparative Example 2, since it is 25 charges to 35 charges, it is sufficient when used as a temporary backup of the decarburizing furnace.

  Further, FIG. 6 shows the relationship between the number of tapping holes, which is the integrated number of times of use of the tapping holes 10, and the tapping time [second / ton] in Examples 1 and 2 and Comparative Example 2. Here, the pouring time is a discharge time taken per unit amount of molten steel. Usually, as the number of tapping holes increases, the tapping holes 10 are melted and the inner diameter d is enlarged, so that the tapping time becomes short. In the graph shown in FIG. 6, it is possible to confirm the erosion rate of the tapping hole 10 by confirming the transition of the tapping time according to the number of tapping holes. As shown in FIG. 6, in either of the first and second embodiments, the number of tapping holes is larger than that of the second comparative example using the thick lining sleeve brick 4 used in ordinary decarburizing treatment. It was confirmed that the shortening of the tapping time due to the increase of the water content was not rapid, and the attrition rate did not become inferior.

DESCRIPTION OF SYMBOLS 1 converter-type smelting furnace 10 hot water discharge hole 2 furnace body shell 3 lining brick 4 lining brick for brick 4A first lining sleeve brick 4B second lining sleeve brick 5 monolithic refractories d, d ₁ , d ₂ Inner diameter (of lining sleeve brick) D, D ₁ , D ₂ Outer diameter of lining sleeve brick d ₁ 'Initial diameter of the first lining sleeve brick

Claims (3)

A method of operating a converter-type smelting furnace having a tapping hole formed of a sleeve brick for lining, comprising:
When making a change to reduce the inside diameter of the tapping hole,
The second lining sleeve brick having a smaller outside diameter than the unused inner diameter of the first lining sleeve brick without removing the first lining sleeve brick provided in the converter-type smelting furnace A method of operating a converter-type smelting furnace, comprising inserting and fixing the first lining sleeve brick inside the first lining sleeve brick. A method of operating a converter-type smelting furnace having a tapping hole formed of a sleeve brick for lining, comprising:
The converter-type smelting furnace including the first lining sleeve brick for forming the tapping hole for the pre-treatment furnace for subjecting the molten metal to at least one of desiliconization treatment and dephosphorization treatment is decarburized to the molten metal When used as a decarburizing furnace to make molten steel
Without removing the first lining sleeve brick from the converter type smelting furnace, the second lining sleeve brick having an outer diameter smaller than the initial inner diameter of the first lining sleeve brick when not used A method of operating a converter-type smelting furnace, wherein the inner diameter of the tapping hole is reduced by inserting and fixing the first lining sleeve brick inside. A method of operating a converter-type smelting furnace for melting molten steel from molten metal using a plurality of converter-type smelting furnaces,
The converter type smelting furnace is used as a pre-treatment furnace for dephosphorizing the molten metal after being used as a decarburizing furnace for decarburizing the molten metal to make the molten steel during one furnace cost, The converter-type smelting furnace of the present invention is divided into the pre-processing furnace and the decarburizing furnace,
The hot metal is subjected to dephosphorization treatment using the pre-treatment furnace, and then the hot metal is subjected to the dephosphorization treatment using the decarburizing furnace that is a converter-type smelting furnace different from the pre-treatment furnace. The molten steel is melted by the charcoal treatment,
When the converter-type refining furnace used as the decarburizing furnace becomes inoperable, the first lining sleeve brick forming the tapping hole is removed from the converter-type refining furnace used as the pre-treatment furnace Instead, a second lining sleeve brick having an outer diameter smaller than the initial inner diameter of the first lining sleeve brick is inserted into the inside of the first lining sleeve brick and fixed. In the method for operating a converter-type smelting furnace, the inner diameter of the tapping hole is reduced and used as the decarburizing furnace.

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