JP2018044199A - Operation method of blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increase of solution loss carbon amount while maintaining a furnace top temperature of a blast furnace in a prescribed temperature range which is lower than conventional ones.SOLUTION: There is provided an operation method of a blast furnace using a sintered ore and a carbon-containing non-burned agglomerate as blast furnace iron raw material, the content of the carbon-containing non-burned agglomerate is 3 mass% to 10 mass% when the blast furnace iron raw material is 100 mass%, and the blast furnace is operated with temperature control with a furnace top temperature of the blast furnace of 100°C to 120°C.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a technique for stably operating a blast furnace.

  In order to stabilize the blast furnace operation, to ensure a sufficient flow of reducing gas in the massive band, or to suppress the instantaneous blow-up of the blast furnace raw material due to increased pressure loss in the massive band It is important to reduce the airflow resistance of the massive band.

  In Patent Document 1, the sintered ore is separated into fine-grained sintered ore and coarse-grained sintered ore, and small-grain coke is mixed in advance with the fine-grained sintered ore. In the blast furnace operation method adopting a charging method classified by particle size for charging ore separately, the average particle size of the fine-grained sintered ore is 3 to 5 mm, and the average particle size of the small-grain coke is A method for operating a blast furnace is disclosed, which is 1.2 to 2.0 times the average particle size of the fine-grained sintered ore.

  The blast furnace operating method described in Patent Document 1 is a method in which a fine sintered ore having an average particle size of 3 to 5 mm is charged into a blast furnace in a state of being premixed with small coke. This makes it difficult to cause problems (deterioration of air permeability around the blast furnace) caused by charging the grain sinter.

  Further, as another method for ensuring the air permeability of the blast furnace massive band, it is conceivable to reduce the pressure loss by reducing the gas volume of the reducing gas by lowering the top temperature of the blast furnace.

JP 2011-202229 A JP 2008-95177 A

  However, the method of Patent Document 1 has the following problems. Since the blast furnace charge contains raw materials other than sintered ore (for example, limestone), there is a concern that the air permeability around the blast furnace charge may decrease when considering the particle size distribution of the entire blast furnace charge. The In addition, when sieving is performed to obtain sintered ore of the desired particle size, the amount of fine-grained sinter that falls under the sieve is large, and the amount of fine-grained sinter used in the blast furnace is There is also concern about not balancing.

On the other hand, in the method of reducing the temperature at the top of the furnace, there is a concern that the use efficiency of the reducing gas (hereinafter referred to as reduction efficiency) is reduced and the amount of solution loss carbon is increased. Here, in the blast furnace, pulverized coal is burned by the gas blown from the tuyeres at the lower part of the furnace to generate CO gas, and CO ₂ is reduced by reducing the ore while the generated CO gas rises in the blast furnace. There is a phenomenon in which gas is generated, and the generated CO ₂ gas collides with coke in the furnace and returns to CO gas again. This regenerated CO gas may be discharged from the blast furnace without contributing to the reduction of the sintered ore. In this specification, the amount of carbon contained in this CO gas is defined as the amount of solution loss carbon. . The unit of the solution loss carbon amount is “kg / tp”, and is represented by the carbon amount per ton of the output.

  On the other hand, if the temperature at the top of the furnace is too low, condensation occurs and the dust collection efficiency of dust discharged from the top of the furnace decreases.

  Then, this invention aims at suppressing the increase in the amount of solution loss carbon, maintaining the furnace top temperature of a blast furnace in the predetermined temperature range lower than before.

(Background to the creation of the present invention)
As described above, in order to ensure the air permeability of the massive band in the blast furnace, the present inventor has studied to lower the temperature at the top of the blast furnace than before and to reduce the gas volume of the reducing gas. By reducing the gas volume of the reducing gas, the pressure loss is reduced and the air permeability of the massive band is improved.

  On the other hand, when the furnace top temperature is lowered, the reduction efficiency is reduced, the amount of solution loss carbon is increased, and there is a concern that the top of the furnace may be condensed. Therefore, intensive studies were conducted on a method for suppressing the increase in the amount of solution loss carbon while maintaining the furnace top temperature in a predetermined temperature range lower than the conventional operating temperature, and the carbon-containing unfired agglomerated ore was determined together with the sintered ore. It was found that the blast furnace was charged at the ratio of

  That is, the present invention is (1) a method of operating a blast furnace using a sintered ore and a carbon-containing unfired agglomerated ore as a blast furnace iron raw material, and when the blast furnace iron raw material is 100% by mass, The content of the unfired agglomerated mineral is 3% by mass or more and 10% by mass or less, and the blast furnace is operated while the temperature at the top of the blast furnace is controlled to 100 ° C. or more and 120 ° C. or less.

  (2) The method for operating a blast furnace according to (1), wherein a yard sintered ore is used as the sintered ore.

(3) The carbon-containing unfired agglomerated mineral is obtained by adding a hydraulic binder to a finely divided iron-containing raw material containing 40 mass% or more of iron and a finely divided carbonaceous material containing 10 mass% or more of carbon. , A granulated product mixed and granulated while adjusting moisture, and has a cold crushing strength of 50 kg / cm ² or more, and a carbon content (TC) in the carbon-containing unfired agglomerated mineral is 15 The method of operating a blast furnace according to (1) or (2), characterized in that it is ˜25% by mass.

  (4) The blast furnace operating method according to any one of (1) to (3), wherein the blast furnace is operated while monitoring the furnace top temperature.

  According to the present invention, it is possible to suppress an increase in the amount of solution loss carbon while maintaining the top temperature of the blast furnace in a predetermined temperature range lower than that in the past.

It is the schematic of the furnace body except the incidental equipment of the blast furnace. It is a graph which shows the relationship between a furnace top temperature and the pressure loss of a lump. It is a graph which shows the relationship between a furnace top temperature and the amount of solution loss carbon. It is the graph which investigated the relationship between the temperature of a sintered ore, and furnace top temperature.

  FIG. 1 is a schematic diagram of a furnace body excluding incidental facilities of a blast furnace. The furnace body 100 includes a furnace opening K, a shaft L connected to the lower end of the furnace opening K, a furnace belly M connected to the lower end of the shaft L, and a morning glory connected to the lower end of the furnace bell M. Part N, tuyere part O connected to the lower end part of morning glory part N, and furnace bottom part P connected to the lower end part of tuyere part O. The shaft portion L is formed in a divergent shape in which the diameter dimension gradually increases from the upper portion toward the lower portion. A tuyere 101 is formed in the tuyere portion O, and hot air is blown into the furnace body through the tuyere 101 together with pulverized coal.

  The furnace top portion 102 of the furnace body 100 is provided with a turning chute (not shown) that rotates around a vertical axis. Entered. Thereby, in the upper part of the furnace port part K and the shaft part L, a massive band 103 in which blast furnace iron raw materials and coke are alternately arranged is formed. Here, although the blast furnace iron raw material consists of a sintered ore and a carbon-containing unbaking agglomerated ore, it mentions later for details. The furnace top part 102 is provided with a temperature detection part 102a for detecting the furnace top temperature T. For the temperature detector 102a, for example, a sonde can be used.

  The lump 103 is sequentially heated by hot air blown from the tuyere 101 while descending the furnace, and the blast furnace iron raw material is melted. That is, the coke combustion and the melting of the blast furnace iron material proceed sequentially at the lower part of the massive band 103, and a substantially conical fusion band 104 is formed from the morning glory part N toward the lower part of the shaft part L.

  The iron component 105 melted in the fusion zone 104 passes through the dripping zone 106, drops toward the furnace bottom P, and is stored in the furnace bottom P as the molten iron 107. Coke or the like descends after passing through the dripping zone 106, accumulates in the furnace bottom P, and forms a conical furnace core 109 on the hot metal 107. An outlet 108 is formed in the furnace bottom P, and the hot metal 107 collected in the furnace bottom P is extracted from the outlet 108 to the outside of the blast furnace.

The present inventor studied reducing the pressure loss of the reducing gas in the massive band 103 by lowering the top temperature T of the blast furnace. FIG. 2 is a graph showing the relationship between the furnace top temperature T and the pressure loss of the massive strip 103. The black circles are actually measured values, and the white circles are the calculated values. That is, by substituting the blast furnace operation data into the Elgan formula shown in the following formula (1) to obtain the coefficient α, and taking into account changes in gas density and viscosity when the furnace top temperature T changes, The pressure loss in the massive band 103 at the temperature T was calculated.
In formula (1), ΔP is the pressure loss [Pa], ΔL is the layer height [m] of the massive band, e is the porosity [−], and d is the particle size [m]. , R is the gas density [kg / m ³ ], m is the gas viscosity [kg / (m · s)], U is the superficial gas flow velocity [m / s], and 0. Is a symbol representing a coke layer, 0. SP is a symbol representing a sintered ore layer of a massive band, Lo is a sintered ore layer height [m], and Lc is a coke layer height [m].

  As is clear from FIG. 2, the pressure loss in the massive band 103 increases as the furnace top temperature T increases, and the pressure loss in the massive band 103 decreases as the furnace top temperature T decreases.

  Further, the present inventor investigated the relationship between the furnace top temperature T and the amount of solution loss carbon (kg / tp), and obtained the result of FIG. Graph I plotted with a rectangular mark is data in the case of charging only a sintered ore as a conventional operation method, that is, a blast furnace iron raw material. The data of graph I was acquired by a test apparatus (for example, BIS furnace) that can simulate the reduction reaction in the blast furnace. The furnace top temperature T was adjusted by adjusting the amount of reducing gas introduced into the BIS furnace. The solution loss carbon amount (kg / tp) was obtained from the difference between the amount of carbon introduced into the furnace and the amount of carbon calculated from the analysis result of the exhaust gas described above by analyzing the exhaust gas discharged from the BIS furnace in a steady state. .

L _SV is a reference value obtained from the operation results. When the amount of solution loss carbon (kg / tp) is larger than the reference value L _SV , the temperature of the cohesive zone 104 is lowered and the operation becomes unstable. In other words, when the amount of solution loss carbon (kg / tp) increases, the sintered ore that has not progressed indirect reduction falls to the cohesive zone 104 and is directly reduced by colliding with coke. Since this is an endothermic reaction, the temperature of the cohesive zone 104 is greatly reduced. Therefore, in addition to lowering the furnace top temperature T in order to reduce the airflow resistance in the massive band 103, it is also extremely important as a blast furnace operating condition to suppress the solution loss carbon amount (kg / tp) below a predetermined value. It is.

As shown in the graph I, in the temperature region where the furnace top temperature T is lower than 120 ° C., the solution loss carbon amount (kg / tp) becomes larger than the reference value L _SV , so that the operation becomes unstable. This tendency becomes more prominent as the furnace top temperature T becomes lower. The reference value L _SV differs depending on the type of blast furnace and cannot be uniquely determined. However, in the present embodiment, the reference value L _SV is 88 (kg / tp) based on the operation results.

In this embodiment, by introducing a predetermined carbon-containing unfired agglomerate together with sintered ore as a blast furnace iron raw material, an increase in the amount of solution loss carbon (kg / tp) is suppressed and the reduction efficiency is improved. ing. Here, after carbonized non-calcined agglomerated granulated pulverized iron-containing raw material and pulverized carbonaceous material, and after increasing the strength of the granulated material by curing (hydration reaction and chlorination treatment of regular coal, etc.) It is a non-fired agglomerated ore that is used as it is as an iron raw material for a blast furnace without being sintered, and a known one can be used as appropriate. When the carbon-containing unfired agglomerated ore is charged into a blast furnace, carbon is gasified at about 800 ° C. to generate CO. Since this CO is generated in the vicinity of iron oxide contained in the carbon-containing unfired agglomerated mineral, iron oxide is easily reduced. Further, CO ₂ generated by reducing iron oxide reacts with carbon to generate CO gas again, and reduces the surrounding sintered ore. Thereby, the indirect reduction | restoration of a blast furnace iron raw material is accelerated | stimulated, and the temperature fall in the cohesive zone 104 can be suppressed.

  The carbon-containing non-calcined agglomerated mineral is preferably prepared by adding a hydraulic binder to a finely divided iron-containing raw material containing 40 mass% or more of iron and a finely divided carbonaceous material containing 10 mass% or more of carbon and adding moisture. It is a granulated product that is mixed and granulated while adjusting.

  As the pulverized iron-containing raw material, one or two of sintered dust and pulverized iron ore can be used. As the pulverized carbonaceous material, one or more of blast furnace primary ash, coke dust, and powder coke can be used. The particle sizes of the finely divided iron-containing raw material and the finely divided carbonaceous material are preferably 1 mm or less, but the optimum particle size configuration differs depending on the raw material properties such as the pore structure and surface shape of the raw material, the molding technique, and the like.

  The hydraulic binder is a binder having a function of increasing the cold crushing strength of the granulated product by curing by a hydration reaction with moisture contained in the raw material or added moisture, and the type of the binder is not particularly limited. . As an example, in this embodiment, an aging binder, Portland cement, and bentonite composed of fine powder mainly composed of blast furnace granulated slag and an alkali stimulant can be used.

  When the total of the finely divided iron-containing raw material, finely divided carbonaceous material and hydraulic binder is 100% by mass, the amount of hydraulic binder added is preferably 5 to 10% by mass. The moisture is preferably adjusted to 5 to 15% by mass. The granulation equipment is not particularly limited, and may be any material having functions of kneading raw materials, hydration, granulation, and product sieving, and kneading machines, granulating machines, etc. are not particularly limited. Absent. The granulated product may be a pellet or a briquette. In the case of pellets, for example, it can be formed into a spherical shape by a disk pelletizer. In the case of a briquette, for example, a bilaterally symmetric pillow-type briquette or almond-type briquette that is provided with a hollow mold and is molded by a pair of opposed molding rolls may be used.

Further, the cold crushing strength of the carbon-containing unfired agglomerated mineral is preferably 50 kg / cm ² or more. By securing a cold crushing strength of 50 kg / cm ² or more, it is possible to obtain a cold strength that can sufficiently withstand the damage caused by impact during transportation and blast furnace loading, so handling during manufacture, transportation to the blast furnace, charging Sometimes there is no worry of pulverization.

  The carbon content (TC) in the carbon-containing unfired agglomerated mineral is preferably 15 to 25% by mass. By setting the carbon content ratio (TC) to 15% by mass or more, in addition to direct reduction of iron oxide of the carbon-containing non-fired agglomerated mineral itself, the carbonization-free non-fired agglomerated mineral is obtained by gasification of surplus carbon. The indirect reduction of the sintered ore located around can be further promoted. On the other hand, by restricting the carbon content (TC) to 25% by mass or less, it is possible to suppress a decrease in crushing strength due to an increase in the distance between iron oxide particles contained in the carbon-containing unfired agglomerated ore. Can do.

In FIG. 3, graph II plotted with triangle marks is obtained by charging 97 mass% of sintered ore and carbon-containing uncalcined agglomerate at a ratio of 3 mass%, and graph III plotted with circle marks is , 90% by mass of sintered ore and 10% by mass of carbon-containing unfired agglomerated ore. The main composition of the carbon-containing unfired agglomerated mineral used was 48.39% by mass of T.Fe, 0.37% by mass of M.Fe, 0.43% by mass of FeO, 2.85% by mass of CaO, SiO ₂ was 2.99% by mass, Al ₂ O ₃ was 1.12% by mass, MgO was 0.13% by mass, and TC was 19.8% by mass. T.Fe is the mass of total iron contained in the carbon-containing non-fired pellet, M.Fe is the mass of metallic iron contained in the carbon-containing non-fired pellet, and TC is the mass of the carbon-containing non-fired pellet. The mass of carbon contained. These data were acquired by a test apparatus (for example, BIS furnace) that can simulate the reduction reaction in the blast furnace, as in the case of Graph I. The carbon-containing non-fired agglomerated pellets were dispersed substantially uniformly in the sintered ore layer in the BIS furnace. The method for controlling the furnace top temperature T and the method for measuring the solution loss carbon amount (kg / tp) are the same as those in the graph I.

From graph II, even if the furnace top temperature T is lowered to 100 ° C., the amount of solution loss carbon (kg / tp) is less than the reference value L _{SV by} charging 3% by mass of the carbon-containing unfired agglomerated ore. It was found that it can be suppressed. Here, even if the top temperature T is lower than 100 ° C. by increasing the content of the carbon-containing unfired agglomerated mineral to 10% by mass from the graph III, the amount of solution loss carbon (kg / tp) is the standard. It turned out that it can suppress to below value _LSV . However, when the furnace top temperature T is lower than 100 ° C., the upper part of the furnace is condensed, and the dust collection efficiency of the dust discharged from the blast furnace is lowered. Therefore, in the present invention, the range of the furnace top temperature T is limited to 100 ° C. or more and 120 ° C. or less.

  Here, the furnace top temperature T can be temperature-controlled using the detection result of the temperature detector 102a. The temperature control may be a method for controlling the temperature of the sintered ore. The sintered ore discharged from the sintering machine is carried to the furnace top 102 of the blast furnace by an endlessly rotating belt, but the sintered ore immediately after being discharged from the sintering machine has a very high temperature. It cools to the temperature (for example, 150 degreeC) suitable for belt conveyance using the exhaust heat cooler provided in the sintering machine exit side. In the present embodiment, by increasing the cooling capacity of the exhaust heat cooler, the temperature of the sintered ore can be lowered, and the furnace top temperature T can be controlled to 100 ° C. or higher and 120 ° C. or lower.

  Moreover, the method of controlling the furnace top temperature T by using a yard sintered ore may be used. Sinter is usually charged immediately after production, but may be temporarily stored in the yard if the timing of charging into the blast furnace does not match. It is called sintered ore. Since the yard sintered ore is cooled to room temperature (it can be exemplified by 25 ° C. depending on the environmental temperature), the top temperature T can be lowered by using it as a blast furnace iron raw material. In addition, you may use together the sintered ore with high temperature immediately after manufacture, and the cooled yard sintered ore.

  Here, conventionally, when the yard sintered ore whose temperature has been lowered to room temperature is charged into the blast furnace as it is, the reduction rate deteriorates due to the temperature reduction of the blast furnace, so the reduction rate is suppressed by increasing the reducing material (pulverized coal). Was. In this embodiment, since the reduction rate reduced by using a yard sintered ore is improved by using a carbon-containing agglomerated ore, the high cost by the increase of a reducing material can be suppressed.

  Furthermore, you may control the furnace top temperature T by changing the usage-amount of a carbon-containing non-baking agglomerated ore. Crystallized water is contained in the solidified binder of the carbon-containing unfired agglomerated mineral, and this crystallized water is thermally decomposed by receiving heat at the time of charging the blast furnace. Since this thermal decomposition reaction is an endothermic reaction, the furnace top temperature T is lowered. Therefore, you may reduce the furnace top temperature T by increasing the usage-amount of a carbon-containing non-baking agglomerated mineral. In addition, you may control the furnace top temperature T by changing content of the binder contained in a carbon-containing non-baking agglomerated ore.

As described above, various methods are included in the method of suppressing the solution loss carbon amount (kg / tp) to the reference value L _SV or less while controlling the furnace top temperature T to 100 ° C. or more and 120 ° C. or less. Therefore, the temperature control method and the composition of the carbon-containing unfired agglomerated mineral are not limited in claim 1.

  Here, when a blast furnace iron raw material is 100 mass%, content of a carbon-containing non-baking agglomerated mineral is 3 mass% or more and 10 mass% or less. That is, the blast furnace iron raw material contains 90 to 97% by mass of sintered ore and 3 to 10% by mass of carbon-containing unfired agglomerated ore.

As shown in graph I in FIG. 3, when 3% by mass or more of the carbon-containing unfired agglomerated ore is not included, the amount of solution loss carbon (kg / tp) is the standard when the furnace top temperature T is 100 ° C. The value L _SV is exceeded. On the other hand, the reason for limiting the content of the carbon-containing unfired agglomerated mineral to 10% by mass or less is as follows.

  FIG. 4 is a graph in which the relationship between the temperature of the sintered ore and the furnace top temperature T is examined. The furnace top temperature T is calculated based on the heat balance calculation based on the raw material temperature, the raw material specific heat, the furnace top gas amount, the furnace top gas composition, the specific heat of each gas composition, and the decomposition heat of the binder contained in the carbon-containing unfired agglomerated ore. Calculated. Graph IV plotted with a rectangular mark is a case where only sintered ore was charged as a blast furnace iron raw material, and graph V plotted with a triangular mark was charged with a carbon-containing unfired agglomerated ore at a rate of 3% by mass. The graph VI plotted with circles is the case where the carbon-containing unfired agglomerated ore was charged at a rate of 10% by mass.

  As shown in Graph VI, when 10% by mass of the carbon-containing unfired agglomerated ore is added in a state where the temperature of the sintered ore is lowered to 25 ° C., the furnace top temperature T is lowered to about 100 ° C. Therefore, if the ratio of the carbon-containing unfired agglomerated mineral exceeds 10% by mass and the sintered ore cooled to room temperature (25 ° C. in the present embodiment) such as a yard sintered ore is used, The furnace top temperature T may be lowered to less than 100 ° C. due to the heat of decomposition of crystal water contained in the unfired agglomerated mineral and the temperature decrease due to sensible heat when the sintered ore is heated. In addition, there is a concern that the increase in the amount of slag charged in the furnace increases the thickness of the fusion zone 104 in the blast furnace and increases the pressure loss in the lower part of the furnace. For the above reasons, the use ratio of the carbon-containing unfired agglomerated mineral contained in the blast furnace iron raw material is set to 3% by mass or more and 10% by mass or less.

Next, an Example is shown and this invention is demonstrated more concretely. In a blast furnace with a blast furnace internal volume of 4000 m ³ level, the operation was based on an operation with a tapping ratio of 2.1, CR (hereinafter referred to as coke ratio): 320 (kg / tp), and oxygen enrichment of 5%. In all operations, the charged TC amount (that is, the total amount of carbon used during blast furnace operation) was made the same. When the reference value L _SV of the solution loss carbon amount (kg / tp) is set to 88 (kg / tp) and the solution loss carbon amount (kg / tp) is smaller than the reference value L _SV , the reduction efficiency is good. evaluated by ○ as being, solution loss amount of carbon in the case (kg / tp) is equal to or larger than the reference value L _SV was evaluated by × as the reducing efficiency is poor. In addition, when the pressure loss of the massive band is 645 hPa or less, it is evaluated as “good” because the permeability of the massive band is good, and when the pressure loss of the massive band exceeds 645 hPa, the permeability of the massive band is poor. It was evaluated by x as being. When the dust discharge became defective due to dew condensation at the top of the furnace, the dust discharge was evaluated as x.

  When the evaluations of reduction efficiency, air permeability, and dust discharge were all ○, the overall evaluation was evaluated as “good”. When any of the reduction efficiency, air permeability, and dust discharge performance was evaluated as x, the overall evaluation was evaluated as x. Table 1 summarizes the data of the base operation, comparative examples and examples.

  Base operation 1 was an operation of only a conventional sintered ore in which no carbon-containing unfired agglomerate was used, and the furnace top temperature T was 130 ° C. Since the furnace top temperature T remained high, the evaluation of the reduction efficiency was ○, but the evaluation of air permeability was ×, and the overall evaluation was ×.

  Base operation 2 is a part of the pulverized coal blown in base operation 1 for the production of carbon-containing unfired agglomerated minerals. 6% by mass of ore was included. Moreover, the temperature of the sintered ore was raised rather than the base operation 1. Since the furnace top temperature T remained high, the evaluation of the reduction efficiency was ○, but the evaluation of air permeability was ×, and the overall evaluation was ×. Comparing base operations 1 and 2, the solution loss carbon amount (kg / tp) was reduced by charging the carbon-containing unfired agglomerated ore, but the furnace top temperature T remained high, so it was breathable. Was found not to improve.

  In Comparative Example 1, the furnace top temperature T was lowered by changing the sintered ore of the base operation 1 to a yard sintered ore. Since the furnace top temperature T decreased to 120 ° C. or lower, the evaluation of air permeability was improved to ○, but the solution loss carbon amount (kg / tp) was increased due to the temperature decrease, so the overall evaluation was x. Therefore, in order to achieve both reduction in the amount of solution loss carbon (kg / tp) and securing of air permeability by diverting a part of the pulverized coal blown in Comparative Example 1 to the production of the carbon-containing unfired agglomerated ore. The optimal amount of carbon-containing unfired agglomerated ore was examined, and the results of Comparative Examples 2-3 and Examples 1-3 were obtained. In these comparative examples and examples, the furnace top temperature T was lowered by using a yard sintered ore at 25 ° C. as in comparative example 1. In addition, the carbon-containing non-fired agglomerated mineral used is 56% by mass of sintered dust (fine powdered iron-containing raw material) and 34% by mass of blast furnace primary ash (fine powdered carbonaceous material), and cement (hydraulic binder) After adding 10% by mass, the mixture was granulated with a pan pelletizer and cured in a yard for 2 weeks.

  In Comparative Example 2, since the content of the carbon-containing unfired agglomerated mineral was only 2% by mass, the evaluation of the reduction efficiency remained as x, and the overall evaluation was also x. In Comparative Example 3, since the carbon-containing non-calcined agglomerated ore contained more than 10% by mass, the evaluation of the reduction efficiency was ○, but the thermal decomposition heat of crystal water contained in the carbon-containing unfired agglomerated ore Due to this increase, the furnace top temperature T decreased to 100 ° C. or lower. For this reason, the dust discharge performance was x, and the overall evaluation was x.

  On the other hand, in Examples 1-3, the usage-amount of a carbon-containing non-baking agglomerated mineral is 3 mass% or more and 10 mass% or less, and the furnace top temperature T is temperature-controlled at 100 degreeC or more and 120 degrees C or less. Therefore, the evaluations of reduction efficiency, air permeability, and dust discharge were all “good”, and the overall evaluation was “good”.

DESCRIPTION OF SYMBOLS 100 Furnace body 101 tuyere 102 furnace top part 102a temperature detection part 103 lump band 104 fusion band 105 iron content 106 dripping band 107 hot metal 108 spout port 109 furnace core

Claims (4)

A method for operating a blast furnace that uses sintered ore and carbon-containing unfired agglomerated ore as a raw material for blast furnace iron,
When the blast furnace iron raw material is 100% by mass, the content of the carbon-containing unfired agglomerated mineral is 3% by mass or more and 10% by mass or less, and the blast furnace top temperature is controlled to 100 ° C. or more and 120 ° C. or less. A method of operating a blast furnace, characterized by operating the blast furnace.   The blast furnace operating method according to claim 1, wherein a yard sintered ore is used as the sintered ore. The carbon-containing non-fired agglomerated mineral is obtained by adding a hydraulic binder to a pulverized iron-containing raw material containing 40 mass% or more of iron and a pulverized carbonaceous material containing 10 mass% or more of carbon and adding moisture. It is a granulated product that is mixed and granulated while adjusting, and has a cold crushing strength of 50 kg / cm ² or more, and a carbon content (TC) in the carbon-containing unfired agglomerated mineral is 15 to 25 mass. The method for operating a blast furnace according to claim 1 or 2, wherein the operating method is%. The blast furnace operating method according to any one of claims 1 to 3, wherein the blast furnace is operated while monitoring the furnace top temperature.