CN110073006A - blast furnace operation method - Google Patents

Abstract

The invention provides a blast furnace operation method capable of controlling the component concentration of a blast furnace raw material to a target component concentration even if the component concentration of a sintering raw material fluctuates. A blast furnace operation method for charging blast furnace raw materials including finished sintered ore, lump iron ore, and auxiliary raw materials into a blast furnace, comprising: a sintering step of sintering the sintering material to form a sintered cake; a crushing step of crushing the sintered cake to form sintered ore; a cooling step of cooling the sintered ore; a screening step of screening the cooled sintered ore into finished sintered ore and return fine; a measurement step of measuring the component concentration of at least 1 of the cooled sintered ore, finished sintered ore, and return fine; and an adjustment step of adjusting the blending amounts of the finished sintered ore, the lump iron ore, and the auxiliary raw material contained in the blast furnace raw material, wherein in the adjustment step, the blending amount of the blast furnace raw material is adjusted using the component concentrations measured in the measurement step.

Description

blast furnace operation method

technical field

The present invention relates to a blast furnace operating method for adjusting the blending amount of blast furnace raw materials, and more particularly, to a blast furnace operating method for measuring the component concentrations of sintered ore as blast furnace raw materials, and using the component concentrations to adjust the blending amounts of blast furnace raw materials.

Background technique

In the blast furnace ironmaking method, iron-containing raw materials such as sintered ore, lump iron ore, and pellets are mainly used as raw materials for blast furnaces at present as iron sources. Here, the sintered ore is a kind of agglomerated ore obtained by adding water in a drum mixer to iron ore having a particle size of 10 mm or less, and in an ironworks. Miscellaneous iron sources such as various dusts generated, raw materials containing CaO such as limestone, quicklime, slag, etc., auxiliary raw materials such as silica, serpentine, dolomite, or refined nickel slag as _SiO2 sources or MgO sources, and powders containing Solid fuel (carbon material) as a binder such as coke, anthracite, etc. is mixed, granulated, and fired.

In recent years, the concentration of iron components contained in sinter raw materials, which are raw materials of sintered ore, has decreased, instead, the concentration of gangue components such as SiO ₂ or Al ₂ O ₃ has increased, and the component concentration of produced ores has become unstable, As a result, even within the same type of ore, the concentration of components at the time of import may vary per ship.

The fluctuation of the component concentration in the sintered raw material causes the fluctuation of the component concentration of the sintered ore as the finished product. In general, the component concentration of the raw material charged into the blast furnace is always under management for reasons such as the management of the slag grade. When a certain component concentration becomes high, it is necessary to add other components as auxiliary raw materials in order to dilute it. Therefore, it is necessary to detect changes in the component concentrations of sinter, lump iron ore, and pellets as soon as possible. Since lump iron ore and pellets themselves are finished products, component concentration analysis is performed at the time of unloading, etc. However, the actual situation is that no on-line component concentration analysis related to the current sinter is performed, and only very low The frequency of the analysis of the component concentration is performed.

If the component concentration of blast furnace raw materials fluctuates due to fluctuations in the component concentration of sintered ore and deviates significantly from the target component concentration and the viscosity of the slag deteriorates, the molten iron temperature needs to be increased in order to maintain the viscosity of the slag. The deterioration of the viscosity of the slag leads to the deterioration of the slag discharge in the lower part of the blast furnace, and thus the air permeability is deteriorated due to the obstruction of the gas flow. In this way, when the component concentration of the blast furnace raw material deviates greatly from the target component concentration, the blast furnace operation becomes unstable, and various countermeasures are required.

As a technique for grasping the grade of sintered ore, for example, Patent Document 1 discloses a technique of predicting the reducibility and reduction-pulverizing property of the finished sintered ore from the filling state of the sintering raw material, and adjusting the blending of the sintering raw material to The blast furnace raw material is adjusted without adjusting the mixing ratio of the blast furnace raw material.

Patent Document 2 discloses a technique of measuring the FeO of the finished sintered ore, and adjusting the binder, granulation moisture, and exhaust air volume of the sintered raw material based on the difference from the target value to be achieved. In addition, Patent Document 3 discloses a technique of similarly measuring FeO of a finished sintered ore, and adjusting the amount of city gas blown into the sintering machine based on the difference from a target value to be achieved.

Patent Document 4 discloses a technique for estimating the composition of the finished sintered ore from the composition of the surface layer of the sintered raw material obtained by a laser type composition analyzer installed in the sintering machine, and reflecting it in the blending of the sintering raw material.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 10-324929

Patent Document 2: Japanese Patent Laid-Open No. 57-149433

Patent Document 3: Japanese Patent Laid-Open No. 2011-038735

Patent Document 4: Japanese Patent Laid-Open No. 60-262926

SUMMARY OF THE INVENTION

The problem to be solved by the invention

However, Patent Documents 1 to 4 disclose a technique of measuring the concentration of a certain component in sintered ore, and using the measured component concentration to adjust the sintering raw material, or to adjust the production conditions of the sintered ore. technology. Patent Documents 1 to 4 do not disclose at all the use of the measured component concentrations of sintered ore to adjust the blending amount of the blast furnace raw material charged into the blast furnace. The component concentration of the sintered ore may also change with the heat level in the sintering reaction, so even if the fluctuation of the component concentration of the sintering raw material is suppressed, the fluctuation of the component concentration of the sintered ore cannot necessarily be suppressed. Therefore, there is a problem that the component concentration of the blast furnace raw material charged into the blast furnace cannot be controlled to the target component concentration. The present invention has been made in view of such a problem of the prior art, and an object of the present invention is to provide a blast furnace operation method capable of controlling the component concentration of blast furnace raw material to a target component concentration even if the component concentration of the sintering raw material fluctuates.

means of solving problems

The features of the present invention for solving the above-mentioned problems are as follows.

(1) a blast furnace operation method, which is a blast furnace operation method for charging a blast furnace with blast furnace raw materials comprising finished sintered ore, lump iron ore and auxiliary raw materials, and the above-mentioned blast furnace operation method has:

Sintering process, sintering raw materials to form sintered cake;

crushing process, crushing the above-mentioned sintered cake to form sintered ore;

cooling process, cooling the above-mentioned sintered ore;

In the screening process, the above-mentioned cooled sintered ore is screened into finished sintered ore and returned ore;

a measuring step of measuring the component concentration of at least one of the cooled sintered ore, the finished sintered ore, and the returned ore; and

an adjustment step of adjusting the compounding amounts of the above-mentioned finished sintered ore, the above-mentioned lump iron ore, and the above-mentioned auxiliary raw materials contained in the above-mentioned blast furnace raw material,

In the said adjustment process, the compounding quantity of the said blast furnace raw material is adjusted using the component concentration measured in the said measurement process.

(2) The blast furnace operating method according to (1), wherein the blast furnace raw material further contains pellets,

In the said adjustment process, the compounding quantity of the said finished sintered ore, the said pellet, the said lump iron ore, and the said auxiliary raw material contained in the said blast furnace raw material is adjusted.

(3) The blast furnace operating method according to (1) or (2), wherein in the measurement step, the amount of the cooled sintered ore, the finished sintered ore, and the returned ore conveyed on a conveyor belt is continuously measured. component concentration of at least 1 of .

(4) The blast furnace operating method according to any one of (1) to (3), wherein in the measurement step, the component concentration of at least one of the finished sintered ore and the returned ore is measured.

(5) The blast furnace operating method according to any one of (1) to (3), wherein in the measurement step, the component concentration of the finished sintered ore is measured.

(6) The blast furnace operating method according to any one of (1) to (5), wherein in the measurement step, one or more of total CaO, SiO ₂ , MgO, Al ₂ O ₃ , and FeO are measured ingredient concentration.

Invention effect

By implementing the blast furnace operating method of the present invention, the component concentration of the blast furnace raw material can be controlled to the target component concentration. Thereby, the fluctuation|variation of the viscosity of a blast furnace slag, etc. can be suppressed, and it can contribute to the stable operation of a blast furnace.

Description of drawings

[ Fig. 1] Fig. 1 is a schematic diagram showing an example of a sintered ore production apparatus 10 capable of implementing the blast furnace operating method according to the present embodiment.

[ Fig. 2] Fig. 2 is a graph showing changes in basicity of blast furnace slag.

[ Fig. 3] Fig. 3 is a diagram showing a change in a focal ratio.

[ Fig. 4] Fig. 4 is a graph showing fluctuations in basicity and coke ratio of blast furnace raw materials.

5 is a graph showing measured values of FeO concentrations in Invention Example 3, Invention Example 4, and Comparative Example 3. [ FIG.

6] FIG. 6 is a graph showing the reduction amount of the focal ratio in Invention Example 3, Invention Example 4, and Comparative Example 3. [FIG.

Detailed ways

In this invention, the measurement process for measuring the component concentration of sintered ore is provided, and the component concentration of sintered ore is measured in this measurement process. These component concentrations are used to adjust the blending amounts of the finished sintered ore, pellets, lump iron ore, and auxiliary raw materials as blast furnace raw materials. As a result, it was found that the component concentration of the blast furnace raw material can be controlled so that the component concentration of the blast furnace raw material becomes the target component concentration, and as a result, the blast furnace operation can be stabilized, thereby completing the present invention. Hereinafter, the present invention will be described with reference to the embodiments of the present invention.

FIG. 1 : is a schematic diagram which shows an example of the sintered ore manufacturing apparatus 10 which can implement the blast furnace operating method which concerns on this embodiment. The sintered ore manufacturing apparatus 10 includes a sintering machine 12 , a primary crusher 14 , a cooler 16 , a secondary crusher 18 , a plurality of screening devices 20 , 22 , 24 , and 26 , an infrared analyzer 28 , a product line 30 , and a return line 32.

The sintering process is performed in the sintering machine 12 . The sintering machine 12 is, for example, a downward suction type Dwight-Lloyd sintering machine. The sintering machine 12 includes a sintering raw material supply device, an endlessly movable pallet, an ignition furnace, and a bellows. The sintered raw material is loaded into the tray from the sintered raw material supply device, thereby forming a loading layer of the sintered raw material. The charging layer is ignited by an ignition furnace, and the air in the charging layer is sucked downward by the bellows, so that the combustion/melting zone in the charging layer is moved below the charging layer. Thereby, the loaded layer is sintered to form a sintered cake. Gas fuel and/or oxygen-enriched air may be supplied from above the loading layer when the air in the loading layer is sucked downward through the bellows. The gaseous fuel is any combustible gas selected from blast furnace gas, coke oven gas, blast furnace/coke oven mixed gas, converter gas, city gas, natural gas, methane gas, ethane gas, propane gas, and a mixed gas thereof .

The crushing process is implemented in the primary crusher 14, and the sintered cake is crushed by the primary crusher 14 into sintered ore. The cooling process is implemented in the cooler 16, and the sintered ore is cooled by the cooler 16, and becomes the cooled sintered ore.

The sieving process is carried out in the sieving apparatuses 20 , 22 , 24 and 26 . In the sieving device 20, the cooled sintered ore is sieved into sintered ore with a particle size larger than 75 mm and sintered ore with a particle size of 75 mm or less. In this embodiment, the particle size refers to the particle size sieved by a sieve. For example, sintered ore with a particle size larger than 75 mm refers to the particle size sieved on a sieve using a sieve with a mesh size of 75 mm. The sintered ore with a diameter of 75 mm or less refers to a particle size sieved under a sieve using a sieve with a mesh size of 75 mm.

The sintered ore with a particle size larger than 75 mm, which is screened on the screen in the screening device 20, is pulverized by the secondary crusher 18 so that the particle size becomes 50 mm or less. The crushed sintered ore and the sintered ore sieved under the sieve are mixed and sieved by the sieving device 22 . Thereby, the upper limit of the particle diameter of the product sintered ore can be made 75 mm or less.

The sintered ore with a particle size of less than 75 mm screened by the screening device 20 is then screened by the screening devices 22, 24 and 26 into finished sintered ore with a particle size larger than 5 mm and returned ore with a particle size of less than 5 mm. The finished sintered ore screened by the screening devices 22 , 24 , and 26 is conveyed to the blast furnace 34 by the conveyor belt as the finished product line 30 . On the other hand, the returned ore screened by the sieving devices 22 , 24 , and 26 is conveyed again to the sintering raw material supply device of the sintering machine 12 by the conveyor belt as the returning ore line 32 . The particle diameters of the sintered ore sieved by the sieving devices 20 , 22 , 24 , and 26 , the particle diameter of the finished sintered ore, and the particle diameter of the returned ore are merely examples, and are not limited to these values.

An infrared analyzer 28 is installed on the conveyor as the finished product line 30 . The infrared analyzer 28 performs the measurement process. In the measurement step, the concentration of one or more of the total CaO, SiO ₂ , MgO, Al ₂ O ₃ , and FeO contained in the finished sintered ore is measured. The infrared analyzer 28 irradiates the sintered ore with infrared rays having a wavelength in the range of 0.5 μm to 50.0 μm, and receives reflected light from the sintered ore. Since the molecular vibration of each of the total CaO, SiO ₂ , MgO, Al ₂ O ₃ , and FeO contained in the sintered ore absorbs the intrinsic wavelength component of the irradiated infrared rays, these components impart intrinsic wavelength components to the reflected infrared rays. Therefore, the component concentrations of total CaO, SiO ₂ , MgO, Al ₂ O ₃ , and FeO in the finished sintered ore can be measured by analyzing the irradiated light and the reflected light. The total CaO refers to a value obtained by converting Ca in all compounds containing Ca and O, such as CaO, CaCO ₃ , Ca(OH) ₂ , Fe ₂ CaO ₄ , to CaO.

The infrared analyzer 28 irradiates infrared rays of 20 or more wavelengths, for example, at a frequency of 128 times per minute, and receives the reflected light reflected by the finished sintered ore. By irradiating infrared rays for a short time in this way, the infrared analyzer 28 can continuously measure the component concentration of the finished sintered ore conveyed on the conveyor belt of the finished product line 30 on-line. The infrared analyzer 28 is an example of a component analysis device, and is not limited to a component analysis device of a method of spectroscopic reflection light, and a component analysis device of a method of spectroscopic transmission light may be used. Furthermore, instead of the infrared analyzer 28, a laser analyzer that irradiates a measurement object with laser light, a neutron analyzer that irradiates a neutron to the measurement object, or a microwave analyzer that irradiates a microwave to the measurement object may be used.

The finished sintered ore whose component concentrations have been measured is transported to the blast furnace 34, and an adjustment step of adjusting the blending amount of the blast furnace raw material including the finished sintered ore, pellets, lump iron ore, and auxiliary raw materials is performed. The blast furnace raw material may contain raw materials other than the above, and may not contain pellets. In the adjustment step, the component concentration of the finished sintered ore measured by the infrared analyzer 28 and the component concentrations of the pellets, lump iron ore, and auxiliary raw materials measured in advance are used to calculate the total component amount of the blast furnace raw materials, and the Calculate the value, and perform feedforward control on the blending amount of the blast furnace raw material so that it becomes the target component concentration. For example, in order to control the basicity (CaO/ _SiO2 ) of a blast furnace raw material to a target component concentration, what is necessary is just to adjust the compounding quantity of the auxiliary raw material contained in a blast furnace raw material.

Assuming that the FeO concentration of the finished sintered ore increases and the FeO concentration of the blast furnace raw material increases, the reducibility of the blast furnace raw material deteriorates. When the reducibility of the blast furnace raw material deteriorates, the indirect reduction (which is an exothermic reaction) decreases, and the direct reduction (which is an endothermic reaction) increases, and the inside of the blast furnace becomes insufficient in heat. In order to eliminate this heat shortage, the blast furnace is further charged with a reducing agent, and the coke ratio in blast furnace operation is increased. Therefore, by controlling the FeO concentration of the blast furnace raw material to the target component concentration, it is possible to suppress an increase in the coke ratio in blast furnace operation and contribute to stable blast furnace operation. For example, in order to control FeO of a blast furnace raw material to a target component concentration, what is necessary is just to adjust the compounding quantity of the lump ore contained in a blast furnace raw material.

In this way, the blending amount of the blast furnace raw material is adjusted so that the component concentration of the blast furnace raw material becomes the target component concentration. In the present embodiment, the measurement frequency of the component concentrations by the infrared analyzer 28 is 128 times per minute, the average value of the component concentrations of the 128 times is calculated once every minute, and the calculated average value of the component concentrations is used every minute. To adjust the mixing amount of blast furnace raw materials.

As described above, the blast furnace operating method according to the present embodiment measures the component concentration of the finished sintered ore conveyed on the finished product line 30 by using the infrared analyzer 28, and uses the component concentration to adjust the blending amount of the blast furnace raw material so as to be the target component concentration . Thereby, even if the component concentration of the sintered raw material fluctuates and the component concentration of the finished sintered ore fluctuates, the component concentration of the blast furnace raw material can be controlled to the target component concentration, and by charging the blast furnace raw material into the blast furnace, the blast furnace operation can be stabilized and suppressed Increase in coke ratio in blast furnace operation.

In this embodiment, the example in which the infrared analyzer 28 is installed on the conveyor belt of the product line 30 to measure the component concentration of the finished sintered ore is shown, but the present invention is not limited to this, and the infrared analyzer 28 may be installed in the sintered ore production apparatus. The component concentration of at least one of the cooled sintered ore, the finished sintered ore, and the returned ore is measured at any position of 10.

In the loading layer in which the sintering raw material is loaded into the tray, the component concentration of the surface layer and the component concentration of the lower layer are greatly different, and the component concentration varies depending on the moisture content of the sintering raw material and/or the state of the sintering raw material supply device. Infrared-based analysis by its nature can only analyze the surface layer of the object to be analyzed. Therefore, the component concentration of the surface layer is different from the component concentration of the lower layer, and even if the infrared analyzer 28 is used to measure the component concentration of the loaded layer whose component concentration fluctuates, the component concentration of the entire loaded layer cannot be measured with high accuracy. On the other hand, after the cooling step, the sintered raw materials are sintered, pulverized, cooled, and mixed to some extent, so that the component concentration of the surface layer and the component concentration of the lower layer are not significantly different. Therefore, in the measurement step of the present embodiment, the component concentration of at least one of the sintered ore, the finished sintered ore, and the returned ore after the cooling step is measured. Thereby, even if it is the infrared analyzer 28 which can analyze only the surface layer of an analysis object, the component concentration can be measured with high precision.

When the particle size distribution of the sinter is wide, for example, infrared rays cannot irradiate the sinter with a small particle size hidden in the sinter with a large particle size, and the infrared ray can only be irradiated to a part of the sinter, and the reflected light from the sinter cannot be irradiated. Also unstable. On the other hand, after the sieving process, the sintered ore has a narrow particle size distribution because it is sieved into finished sintered ore with a particle size of more than 5 mm and returned ore with a particle size of 5 mm or less. Therefore, in the measuring step, it is preferable to measure the component concentration of at least one of the finished sintered ore and the returned ore after the sieving step. Accordingly, the infrared analyzer 28 can irradiate the sintered ore uniformly with infrared rays, and since the reflected light from the sintered ore is also stable, the component concentration can be measured with higher accuracy.

After the sieving step, the component concentration of the finished sintered ore or the returned ore is measured in the measurement step. However, compared with the measurement of the returned ore, the component concentration of the finished sintered ore used as one of the blast furnace raw materials can be directly measured by measuring the finished sintered ore. , so it is more preferable.

Example 1

The component concentrations of total CaO, SiO ₂ , MgO, Al ₂ O ₃ , and FeO contained in the finished sintered ore were measured once per minute using the sintered ore manufacturing apparatus 10 in which the infrared analyzer 28 was installed in the finished product line 30 . Invention Example 1 is an operation example in which the blending amount of the auxiliary raw material of the blast furnace raw material was adjusted at a frequency of once per minute using the measurement result. Comparative Example 1 is an operation example in which the blending amount of the auxiliary raw material of the blast furnace raw material was not adjusted. The fluctuation of the basicity of the blast furnace slag and the coke ratio of the blast furnace in Comparative Example 1 and Inventive Example 1 were measured.

FIG. 2 is a graph showing changes in basicity of blast furnace slag. FIG. 2( a ) shows the variation of the basicity of Comparative Example 1, and FIG. 2( b ) shows the variation of the basicity of Inventive Example 1. FIG. In FIG. 2 , the horizontal axis is time (day), and the vertical axis is total CaO/SiO ₂ (−). The value of basicity shown in FIG. 2 is the value measured by the on-line chemical analysis of the components of molten iron tapped from a blast furnace and blast furnace slag.

As shown in FIG. 2 , in Comparative Example 1, the alkalinity fluctuates greatly around the target value. On the other hand, in Inventive Example 1, the component concentration of the finished sintered ore was measured once a minute, and the composition of the blast furnace raw material was adjusted so that the component concentration of the blast furnace raw material would be the target value using the component concentration. The deviation from the target value of alkalinity becomes smaller. In this way, it was confirmed that by implementing the blast furnace operating method according to the present embodiment, the deviation of the basicity of blast furnace slag from the target value can be reduced.

FIG. 3 is a graph showing a change in a focal ratio. In FIG. 3 , the horizontal axis is time (day), and the vertical axis is focal ratio (kg/t-pig). Days 0 to 19 are the coke ratios of Comparative Example 1 in which blast furnace raw materials with unadjusted blending amounts were charged for blast furnace operation, and days 20 to 39 were blast furnace operations performed with blast furnace raw materials whose blending amounts were adjusted once per minute. Focal ratio of Invention Example 1.

As shown in FIG. 3 , compared with Comparative Example 1, the coke ratio in the blast furnace operation of Inventive Example 1 became lower. In this way, it was confirmed that the blast furnace operation was stabilized by implementing the blast furnace operation method according to the present embodiment, and as a result, the increase in the coke ratio of the blast furnace operation could be suppressed.

Example 2

FIG. 4 is a graph showing fluctuations in the basicity of blast furnace raw materials and fluctuations in coke ratio. FIG. 4( a ) shows changes in the basicity of the blast furnace raw materials of Comparative Example 2 and Invention Example 2. FIG. In FIG. 4( a ), the horizontal axis represents time (hours), and the vertical axis represents total CaO/SiO ₂ (−) of blast furnace raw materials. FIG.4(b) shows the fluctuation|variation of the coke ratio of the blast furnace operation of the comparative example 2 and the invention example 2. FIG. In FIG. 4( b ), the horizontal axis is time (hours), and the vertical axis is focal ratio (kg/t-pig).

In FIG. 4, Comparative Example 2 is an operation example in which the total CaO and _SiO2 of the finished sintered ore were measured at a frequency of once every 2 hours using fluorescent X-rays, and the results of the measurement were used to adjust the blast furnace raw material at the same frequency. Amounts of auxiliary raw materials. Inventive Example 2 is an operation example in which the infrared analyzer 28 installed on the finished product line 30 is used in the same manner as in Inventive Example 1, and the total CaO and SiO ₂ component concentrations of the finished sintered ore are obtained at a frequency of once a minute, and Using this measurement result, the blending amount of the auxiliary raw material for the blast furnace raw material was adjusted at the same frequency.

In the example shown in FIG. 4 , the blast furnace operation was performed under the conditions of Comparative Example 2 for 0 to 6 hours, and the blast furnace operation was performed under the conditions of Invention Example 2 for 6 hours to 19 hours. As shown in FIG. 4( a ), in Comparative Example 2, the blending amount of the auxiliary raw material was adjusted at the frequency of once every 2 hours. Therefore, it can be seen that the basicity of the blast furnace raw material fluctuates by the measurement once every 2 hours. be suppressed. However, when changing from Comparative Example 2 to Inventive Example 2 and adjusting the blending amount of the auxiliary raw material of the blast furnace raw material at a frequency of once a minute, as shown in FIG. The time band in which the amount of blast furnace raw material is charged into the blast furnace begins, and the coke ratio of blast furnace operation decreases. Generally, the sintered ore discharged from a sintering machine is cooled by a cooling machine, and after sizing, it is charged into a blast furnace through a storage tank of the blast furnace. Although it also depends on the size of the ore storage tank, the retention time of the raw material in the ore storage tank used in this example is about 8 hours, and it can be estimated that the effect gradually appears in the blast furnace after 8 hours.

In view of this, it is considered that the basicity of the blast furnace raw material fluctuates during this period, and the coke ratio of Comparative Example 2 is increased due to the fluctuation of the basicity by the measurement once every 2 hours. On the other hand, in Inventive Example 2, it is considered that the infrared analyzer 28 was installed on the finished product line 30 to measure the total CaO and SiO ₂ of the finished sintered ore at a frequency of once a minute, and the measurement results were used to make By adjusting the blending amount of the auxiliary raw material so that the basicity of the blast furnace raw material becomes the target value, fluctuations in the basicity of the blast furnace raw material are suppressed even for 2 hours, and as a result, an increase in the coke ratio in blast furnace operation can be suppressed.

Example 3

5 is a graph showing measured values of FeO concentrations in Invention Example 3, Invention Example 4, and Comparative Example 3. FIG. In FIG. 5 , the vertical axis is the measured value (mass %) of FeO concentration at a specific time.

Invention Example 3 is an operation example in which the infrared analyzer 28 is installed on the finished product line 30, and the component concentrations of total CaO, SiO ₂ , MgO, Al ₂ O ₃ and FeO in the finished sintered ore are measured once a minute. , and the blending amount of the auxiliary raw material for the blast furnace raw material was adjusted at a frequency of once a minute using the measurement results. Invention Example 4 is an operation example in which the infrared analyzer 28 is installed on the ore returning line 32, and the components of total CaO, SiO ₂ , MgO, Al ₂ O ₃ and FeO in the finished sintered ore are measured once a minute. The concentration was used to adjust the blending amount of the auxiliary raw material for the blast furnace raw material at a frequency of once a minute. Comparative Example 3 is an operation example in which the infrared analyzer 28 is installed at a position where the surface of the sintered cake of the sintering machine 12 can be measured, and the total CaO, SiO ₂ , MgO and Al on the surface of the sintered cake are measured once a minute. The component concentrations of ₂ O ₃ and FeO were used to adjust the blending amounts of the auxiliary raw materials for the blast furnace raw materials at a frequency of once per minute using the measurement results.

As shown in FIG. 5 , the FeO concentration when the finished sintered ore was measured was 7.1 mass %, whereas the FeO concentration when the returned ore produced from the same sintering raw material was measured was 6.9 mass %. From this result, it is understood that there is no significant difference between the results of measuring the FeO concentration of the returned ore and the results of measuring the FeO concentration of the finished sintered ore using an infrared analyzer. On the other hand, the FeO concentration when the surface of the sintered cake obtained by sintering the same sintering raw material was measured using the infrared analyzer 28 was 5.6 mass %, which was significantly different from the FeO concentration when the finished sintered ore was measured.

Infrared analyzers by their nature can only measure the concentration of components on surfaces irradiated with infrared rays. Since the finished sintered ore and the returned ore are crushed and mixed to some extent in the process, the overall average composition can be obtained by irradiating the surface with infrared rays. On the other hand, since the component concentrations of the sintering raw materials loaded into the tray are different in the upper and lower layers, and the thermal levels of the upper and lower layers during sintering are different, the component concentrations in the upper and lower layers of the sintered cake are greatly different. Therefore, as shown in FIG. 5, it is considered that there is a large difference between the component concentrations of Comparative Example 3 obtained by measuring the surface of the sintered cake with an infrared analyzer and the component concentrations of Inventive Example 3 obtained by measuring the surface of the finished sintered ore.

FIG. 6 is a graph showing the reduction amount of the focal ratio in Invention Example 3, Invention Example 4, and Comparative Example 3. FIG. In FIG. 6 , the vertical axis is the focal ratio reduction amount (kg/t-pig). The reduction amount of coke ratio shown in FIG. 6 is before adjusting the blending amount of blast furnace raw material and after adjusting the blending amount of blast furnace raw material by Inventive Example 3, Inventive Example 4, and Comparative Example 3, it is estimated that the influence of the operation fluctuation is weakened and becomes stable. The amount of reduction in coke ratio after 120 hours of operation under state conditions.

Invention Example 3 in which the blending amount of auxiliary raw materials for blast furnace raw materials was adjusted using the component concentration of the finished sintered ore charged into the blast furnace as the blast furnace raw material, and the blast furnace was adjusted using the component concentration of the returned ore that did not differ from the component concentration of the finished sintered ore In Inventive Example 4 of the compounding amount of the auxiliary raw material of the raw material, the coke ratio decreased when 120 hours passed. On the other hand, in Comparative Example 3 in which the blending amount of the auxiliary raw material for the blast furnace raw material was adjusted using the measured value of the sintered cake with a large difference in component concentration compared with the finished sintered ore charged into the blast furnace, when 120 hours passed, the The focal ratio increases instead. This is considered to reflect the fact that in Comparative Example 3, the component concentration of the blast furnace raw material charged into the blast furnace was not adjusted to the target component concentration.

Description of reference numerals

10 Sinter production equipment

12 Sintering machine

14 Primary Crusher

16 Cooler

18 Secondary Crusher

20 Screening device

22 Screening device

24 Screening device

26 Screening device

28 Infrared Analyzer

30 Finished Lines

32 Return line

34 blast furnace

Claims (6)

1. method for operating blast furnace, high for that will be packed into comprising the blast furnace raw material of finished product sinter, block iron ore and auxiliary material The method for operating blast furnace of furnace, the method for operating blast furnace include

Raw materials for sintering is sintered to form sinter cake by sintering process；

Broken process, by the break of sinter cake to form sinter；

Cooling process, the sinter is cooling；

Process is sieved, the sinter after cooling is sieved as finished product sinter and returned mine；

Mensuration operation, measure the sinter after cooling, the finished product sinter and it is described return mine at least 1 ingredient Concentration；And

Process is adjusted, the finished product sinter, described block of iron ore contained by the blast furnace raw material is adjusted and the auxiliary is former The use level of material,

In the adjustment process, matching for the blast furnace raw material is adjusted using the constituent concentration measured in the mensuration operation Resultant.

2. method for operating blast furnace as described in claim 1, wherein

The blast furnace raw material also contains pelletizing,

In the adjustment process, the finished product sinter, the pelletizing contained by the blast furnace raw material, described block of iron ore are adjusted The use level of stone and the auxiliary material.

3. method for operating blast furnace as claimed in claim 1 or 2, wherein in the mensuration operation, METHOD FOR CONTINUOUS DETERMINATION is in conveyer belt The sinter after cooling of upper conveying, the finished product sinter and it is described return mine at least 1 constituent concentration.

4. method for operating blast furnace as claimed any one in claims 1 to 3, wherein in the mensuration operation, described in measurement Finished product sinter and it is described return mine at least 1 constituent concentration.

5. method for operating blast furnace as claimed any one in claims 1 to 3, wherein in the mensuration operation, described in measurement The constituent concentration of finished product sinter.

6. the method for operating blast furnace as described in any one of claims 1 to 5, wherein

In the mensuration operation, total CaO, SiO are measured₂、MgO、Al₂O₃, one or more of FeO constituent concentration.