JP2019167615A - Charging method of raw material for bell-less blast furnace - Google Patents

Abstract

To provide a raw material charging method for a bell-less blast furnace capable of drying an ore raw material having a yard sintered ore containing moisture without providing a facility for introducing a heating gas.SOLUTION: In the raw material charging method for a bell-less blast furnace, raw material coke 2b and ore raw material 2a are successively layered. The ore raw material 2a contains the yard sintered ore having a moisture content of 1 mass% or more in an amount of 15 mass% or more based on the amount of the ore raw material to be charged. When the ore raw material 2a stored in the top bunker 1 is charged into the charging chute 5 from the furnace port of the blast furnace 6, the ore raw material 2a is charged into the charging chute 5 from the port of the blast furnace 6 at a charging speed v (t/s) of 0.008 (t/s m)×d(m) or less, where d (m) is a diameter of the furnace port of the blast furnace 6.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a raw material charging method for a bell-less blast furnace in which a raw material containing coke and an ore raw material is charged into a blast furnace, and in particular, a raw material containing an ore raw material containing a yard sintered ore containing moisture and coke. The present invention relates to a raw material charging method for a bell-less blast furnace.

  In a blast furnace, iron ore, coke, and a coagulant are used as raw materials and charged into the blast furnace from the top of the furnace, and high-temperature air or high-temperature air enriched with oxygen is blown into the furnace from the bottom of the furnace to burn the coke. Hot metal is produced by reducing and melting iron ore using heat and CO gas generated by combustion. The raw material charged from the top of the furnace is adjusted to a granular raw material having a particle size of several mm to several tens of mm and charged into the blast furnace, so the combustion gas generated by the combustion of coke at the lower part of the furnace is the furnace. The gap between the granular raw materials charged in the inside rises toward the top of the furnace.

Since heat supply to the raw material in the blast furnace is mainly performed by heat transfer from this combustion gas, if the flow of the combustion gas in the furnace is not in an appropriate state, the temperature rise of the raw material becomes unstable, and iron ore This will hinder reduction and melting. Therefore, in order to make the gas flow in the furnace appropriate, when charging the raw material at the top of the furnace into the blast furnace, Development of raw material charging methods is underway.
However, even if such a raw material charging device or a raw material charging method is devised, if powder is mixed in the raw material itself, mixing of the powder into the blast furnace cannot be avoided, and the combustion gas in the blast furnace cannot be avoided. It is difficult to optimize the flow.

  The raw materials charged in the blast furnace are the raw materials that are manufactured in a sintering machine or coke oven and directly sent to the raw material tank of the blast furnace after the particle size adjustment. After being stored at, there is a raw material that is recovered and sent to the raw material tank of the blast furnace. Among these raw materials, those that are sent to the blast furnace raw material tank after being stored in the yard are inevitably wet with rainwater when stored in the yard, and the water content becomes several mass%. Some raw materials have a water content exceeding 10% by mass. In particular, a sintered ore that is stored in a yard and then sent to a blast furnace raw material tank is called a yard sintered ore, and the yard sintered ore often contains 1.0 mass% or more of moisture. . There is also an ore raw material containing 15 mass% or more of a yard sintered ore having a moisture content of 1.0 mass% or more with respect to the amount of the ore raw material charged.

In such a raw material with a high water content, the powder raw material adheres to the particles of the raw material due to moisture, and thus the powder raw material may not be completely removed even if the particle size is adjusted using a sieve or the like. Moreover, since the powder raw material containing such moisture adheres to the sieve net itself, it causes clogging of the sieve and further makes it difficult to screen the raw materials.
The powder raw material that could not be removed by the sieve is transported to the raw material charging device of the blast furnace while adhering to the raw material and charged into the blast furnace. The powdered raw material is dried in the blast furnace by the heat of the gas in the furnace and is released from the surface of the raw material, flows through the gap between the raw materials in the furnace, and in some cases the powdered raw material accumulates in the gap between the raw materials, Obstructs flow.

Therefore, the technology to dry the raw material and the technology to dry the raw material and remove the powder raw material adhering to the raw material before charging into the furnace are as important as the technology for charging the raw material into the blast furnace. I can say that.
Conventionally, as a drying preheating method of a blast furnace raw material, for example, the one shown in Patent Document 1 is known.
The blast furnace raw material drying preheating method shown in Patent Document 1 introduces a heating gas for drying and preheating the raw material in the hopper into the hopper for storing the blast furnace raw material, and discharges the stored and preheated raw material from the hopper. When the raw material from which the powder raw material has been removed is charged into the blast furnace, the inside of the hopper is evacuated to maintain a negative pressure with respect to the outside.
Thereby, the raw material powder can be removed before being dried and charged in the furnace.

JP 2008-303433 A

However, the conventional blast furnace raw material drying preheating method disclosed in Patent Document 1 has the following problems.
That is, in the drying preheating method of the blast furnace raw material shown in Patent Document 1, a facility for introducing a heating gas for drying and preheating the raw material in the hopper is required. There was a problem that a space for installing was also required.
Accordingly, the present invention has been made to solve this conventional problem, and its purpose is to provide an ore raw material containing a yard sintered ore containing moisture without providing a facility for introducing a heating gas. The object is to provide a raw material charging method for a bell-less blast furnace that can be dried.

In order to achieve the above object, a method for charging a raw material for a bellless blast furnace according to an aspect of the present invention is a method for charging a raw material for a bellless blast furnace in which raw material coke and ore raw material are sequentially charged in layers, In the raw material charging method of the bell-less blast furnace in which the ore raw material contains 15 mass% or more of the yard sintered ore with a moisture content of 1 mass% or more with respect to the charged ore raw material amount, it is stored in the furnace top bunker. In addition, when the ore raw material is charged into the charging chute from the blast furnace outlet, 0.008 (t / s · m ² ) where the diameter of the blast furnace outlet is d (m). The gist is that the charging chute is charged into the charging chute from the blast furnace at a charging speed v (t / s) of xd ² (m ² ) or less.

  According to the raw material charging method of the bell-less blast furnace according to the present invention, since the charging speed of the ore raw material into the charging chute is reduced and the charging time of the ore raw material is lengthened, the facility for introducing the heating gas is provided. The raw material charging method of the bell-less blast furnace which can dry the ore raw material containing the yard sintered ore containing a water | moisture content can be provided.

It is a schematic diagram of the furnace top part of the bell-less blast furnace to which the raw material charging method of the bell-less blast furnace according to one embodiment of the present invention is applied. It is a figure for demonstrating the small model test which verifies how much the yard sintered ore containing a moisture is dried by the gas sensible heat in a blast furnace. In the small model test shown in FIG. 2, the time-dependent change in the moisture content in the yard sintered ore at a temperature of 200 ° C. after passing through the sintered layer and a superficial velocity of 0.02 m / s. It is a graph which shows. It is a graph which shows the change with respect to the superficial velocity of the drying speed obtained from the result shown in FIG. 3 for every warm air temperature after passing a sintered layer. It is a graph which shows the change with respect to the elapsed time from the charging start of the furnace top gas temperature in charging an ore raw material on the conditions whose charging speed of an ore raw material is 1.0 t / s and 2.0 t / s. It is a graph which shows the relationship between the charging speed of the ore raw material in a real machine test, and the ventilation resistance index of the upper part of a blast furnace.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, the drawings are schematic. For this reason, it should be noted that the relationship between the thickness and the planar dimension, the ratio, and the like are different from the actual ones, and the dimensional relationship and the ratio are different between the drawings. Further, the following embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, structure, and arrangement of components. Etc. are not specified in the following embodiments.

FIG. 1 shows the top of a bell-less blast furnace to which the method of charging a bell-less blast furnace according to an embodiment of the present invention is applied. One of two or more furnace top bunker 1 installed at the top of the furnace is shown. First, ore raw material 2a discharged from a conveyor belt (not shown) is stored, and coke 2b is stored in the other one.
Here, the ore raw material is an ore containing 15 mass% or more of a yard sintered ore having a water content of 1 mass% or more with respect to the amount of the ore raw material charged.

A flow rate adjusting gate 3 is provided in the raw material charging passage below each furnace top bunker 1. Each flow rate adjusting gate 3 adjusts the opening degree when the ore raw material 2a or coke 2b stored in the furnace top bunker 1 passes, and the ore raw material 2a or coke 2b to be charged into the charging chute 5 described later. The flow rate, that is, the charging speed v (t / s) which is the mass charged per unit time of the ore raw material 2a or the coke 2b is adjusted.
The lower part of the flow rate adjusting gate 3 in each raw material charging passage is concentrated in the vertical chute 4, and the ore raw material 2 a or the coke 2 b that has passed through each flow rate adjusting gate 3 is transferred from the vertical chute 4 to the charging chute 5 in the blast furnace 6. It is thrown in. The cross section of the vertical chute 4 has an annular shape in which the inner peripheral surface is circular. The charging of the ore raw material 2a into the charging chute 5 and the charging of the coke 2b into the charging chute 5 are alternately performed at predetermined time intervals.

  The charging chute 5 turns around the blast furnace central axis and charges the ore raw material 2a or coke 2b into the blast furnace 6 while changing the tilt angle θ. The arrow a in FIG. 1 shows the turning of the charging chute 5, and the arrow b shows the fall of the ore raw material 2a or the coke 2b. When charging the ore raw material 2a or coke 2b into the blast furnace 6, the charging chute 5 is swiveled and the tilt angle is changed in order to cover a wide range on the raw material deposition surface 7 at the top of the blast furnace 6. Thus, the ore raw material 2a or the coke 2b can be charged. The charging of the ore raw material 2a into the charging chute 5 and the charging of the coke 2b into the charging chute 5 are alternately performed every predetermined time, and the raw coke 2b and the ore raw material 2a can be charged in layers. .

Here, after the ore raw material 2 a is stored in the furnace top bunker 1, the flow rate is adjusted by the flow rate adjusting gate 3, and then charged from the vertical chute 4 to the charging chute 5.
In this embodiment, when the ore raw material 2a is charged from the vertical chute 4 to the charging chute 5, when the ore raw material 2a has a diameter of the furnace port of the blast furnace 6 as d (m), 0.008 The vertical chute 4 is charged into the charging chute 5 at a charging speed v (t / s) of (t / s · m ² ) × d ² (m ² ) or less.

The ore raw material 2a is charged into the charging chute 5 by charging the ore raw material 2a into the charging chute 5 from the furnace port of the blast furnace 6 at a charging speed v (t / s) of 0.008 × d ² or less. By reducing the speed, the charging time of the ore raw material 2a can be extended. Thereby, the time for the yard sintered ore having a high water content to contact the high-temperature furnace gas on the raw material deposition surface 7 in the blast furnace 6 increases, and the drying with the high-temperature furnace gas proceeds. For this reason, the raw material charging method of the bell-less blast furnace which can dry the ore raw material 2a containing the yard sintered ore containing a water | moisture content can be provided, without providing the installation which introduces heated gas.

Moreover, the powder contained in the yard sintered ore is easily discharged as dust by the drying with the high-temperature furnace gas. As a result, the amount of powder contained in the ore layer deposited in the blast furnace 6 can be reduced, and the air permeability of the upper part of the blast furnace 6 can be improved.
In the present embodiment, the ore raw material 2 a is charged from the furnace port of the blast furnace 6 at a charging speed v (t / s) of 0.008 (t / s · m ² ) × d ² (m ² ) or less. The grounds for making the changes will be described below.
The present inventors verified in advance by conducting a small model test how much the yard sintered ore containing moisture was dried by gas sensible heat in the blast furnace 6. This small model test will be described with reference to FIG.

  As shown in FIG. 2, the inside of the cylindrical vessel 10 having an opening at the top and an opening 12 through which hot air can be introduced at the center of the bottom 11 has a particle size equivalent to that of sintered ore normally used in a blast furnace. Sintered ore 13 obtained by mixing sintered ore containing 1.5 mass% of moisture into the sintered ore (yard sintered ore) is charged so as to form a layer thickness T of about 160 mm. The cylindrical container 10 has an inner diameter D of 580 mm (radius is 290 mm). Thereafter, hot air simulating blast furnace top gas is introduced from the opening 12 formed in the bottom 11 of the cylindrical container 10 in the direction indicated by the arrow in FIG. 2, and the weight change of the cylindrical container 10 is measured. The change with time of the amount of water in the sintered ore is measured. The temperature of the warm air was adjusted so that the temperature of the warm air after passing through the sintered layer (sintered ore 13) was 200 ° C to 300 ° C. In this small model test, the superficial velocity (the rising speed of the warm air in the space above the sintered layer in the cylindrical vessel 10) is set to a maximum of 0.1 m / s, which is 1/10 of the actual blast furnace gas velocity of the blast furnace. The test was conducted to the extent of the degree.

As an example of the time-dependent change in the moisture content in the yard sintered ore, the hot air temperature after passing through the sintered layer is 200 ° C. and the superficial velocity is 0.02 m / s. The change over time in the water content is shown in FIG.
The moisture content in the yard sinter decreased linearly up to 0.5 mass%, and the drying rate (mass% / s) tended to decrease below 0.5 mass%. Here, the drying rate (mass% / s) is a value obtained by dividing the water content (mass%) by time (s). The drying speed (mass% / s) is calculated from the time s required to reduce the water content to 0.5 mass%, and the superficial velocity (m / s) of the calculated drying speed (mass% / s). FIG. 4 shows the change with respect to each hot air temperature (° C.) after passing through the sintered layer.

  Referring to FIG. 4, it can be seen that when the hot air temperature after passing through the sintered layer is increased or the superficial velocity is increased, the drying rate is increased. In the small model test, the superficial velocity was tested up to a maximum of 0.10 m / s. However, when the superficial velocity was in the range from 0 to 0.10 m / s, the drying rate increased linearly, Increasing the inlet gas velocity to 1.0 m / s (the superficial velocity is a maximum of 0.10 m / s), at the furnace top gas temperature of 200 ° C. (the hot air temperature after passing through the sintered layer is 200 ° C.), 0.5 mass% / It is estimated that a drying rate of about min is obtained.

  In normal blast furnace operation, the ore raw material 2a including the yard sintered ore is stored for 1 min (60 s) until it is charged into the furnace of the blast furnace 6 from the furnace top bunker 1, and the ore raw material 2a is discharged from the furnace top bunker 1. Until then, the yard sinter and the home-made sinter are mixed so that the moisture content in the yard sinter is dried by about 0.5 mass%. For this reason, it is thought that the drying promotion effect in a furnace is exhibited when a yard sintered ore contains the water | moisture content of 1.0 mass% or more. That is, before the ore raw material 2a is discharged from the furnace top bunker 1, the moisture content in the yard sintered ore is dried by about 0.5 mass%, and the moisture of about 0.5 mass% is dried at the furnace port of the blast furnace. When the yard sintered ore contains less than 1.0 mass% of moisture, the moisture in the yard sintered ore is dried without adjusting the charging speed v (t / s) of the ore raw material 2a. It will be.

Even when the weight ratio of the yard sintered ore in the sintered raw material is less than 15 mass%, the amount of moisture brought into the blast furnace 6 is small, so the charging speed v (t / s) of the ore raw material 2a is adjusted. Soon, the water in the yard sinter will dry out.
Therefore, in the raw material charging method for the bell-less blast furnace according to the present embodiment, the ore raw material containing the yard sintered ore having a water content of 1 mass% or more is the target of charging speed adjustment.
Moreover, in the raw material charging method of the bell-less blast furnace according to the present embodiment, the ore raw material 2a that is the target of charging speed adjustment is charged with a yard sintered ore having a moisture content of 1 mass% or more. The ore contains 15 mass% or more of the ore raw material amount.
Based on this guideline, an actual machine test was performed in which the charging speed v (t / s) of the ore raw material 2a including the yard sintered ore into the charging chute 5 was changed, and the ventilation resistance index at the top of the blast furnace was measured. The actual machine test was conducted under the following conditions. The actual machine is equivalent to that shown in FIG.

In the blast furnace 6 having an internal volume of 5153 m ³ and a furnace diameter of 11.4 m, an ore and a yard sintered ore having a water content of 1 mass% or more are cut out from a storage tank (not shown) and stored in the furnace top bunker 1. And the ore raw material 2a which consists of an ore and a yard sintered ore with a water content of 1 mass% or more was thrown into the charging chute 5 from the furnace top bunker 1 through the flow rate adjusting gate 3, and was deposited in the blast furnace 6. . The charging amount of the ore raw material 2a was determined from the tapping ratio and the coke ratio, and was 95 to 100 t (tons). The tilt angle θ of the charging chute 5 is adjusted to an angle where the ore raw material falling position is 0.5r, where r is the furnace radius, and then the tilt angle θ is sequentially increased for each turn. After the fall position of 2a reached 0.9r, the tilt angle θ was sequentially decreased for each turn, and the fall position of the ore raw material 2a in the final turn was adjusted to 0.5r. The number of turns of the charging chute 5 when a predetermined amount of ore raw material 2a was charged was set, and the opening of the flow rate adjusting gate 3 was adjusted accordingly. For example, the number of turns of the charging chute 5 is set to 10 rpm, and the ore raw material 95t is opened from the furnace top bunker 1 to the charging chute 5 while the charging chute 5 is rotated 10 times. The degree was adjusted. In this case, the charging speed v (t / s) of the ore raw material 2a is 95t ÷ 60s = 1.58 (t / s). The test was conducted by adjusting the number of turns of the charging chute 5 and the opening of the flow rate adjusting gate 3 to adjust the charging speed v (t / s) of the ore raw material 2a to 0.8 to 2.8 t / s. .

  FIG. 5 shows changes in the furnace top gas temperature during charging of the ore raw material 2a under conditions where the charging speed v (t / s) of the ore raw material 2a is 1.0 t / s and 2.0 t / s. . Under the condition where the charging speed v (t / s) is 1.0 t / s, the furnace top gas temperature is reduced from 400 ° C. to 120 ° C. after 100 s from the start of charging the ore raw material 2a. On the other hand, under the condition where the charging speed v (t / s) is 2.0 t / s, the furnace top gas temperature is changed from 400 ° C. to 120 ° C. after 50 seconds from the start of the charging of the ore raw material 2a. descend. And the average of the furnace top gas temperature from the start of the charging of the ore raw material 2a to the passage of 100 s is 260 ° C. and the charging speed v under the condition that the charging speed v (t / s) is 1.0 t / s. (T / s) was 195 ° C. under the condition of 2.0 t / s. From the small model test shown in FIG. 4, the drying rate when the furnace top gas temperature is 250 ° C. is estimated to be 0.6 mass% / min, and the drying rate when the furnace top gas temperature is 200 ° C. is estimated to be 0.5 mass% / min. It is. Therefore, the difference in the amount of drying until 100 s has elapsed since the start of the charging of the ore raw material 2a under the conditions where the charging speed v (t / s) of the ore raw material 2a is 1.0 t / s and 2.0 t / s is , (0.6−0.5) × 100/60 = 0.2 mass%. Therefore, the dry amount under the condition that the charging speed v (t / s) of the ore raw material 2a is 1.0 t / s is the dry amount of the ore raw material 2a having the charging speed v (t / s) of 2.0 t / s. Greater than dryness under conditions.

Moreover, the relationship between the charging speed v (t / s) of the ore raw material 2a and the ventilation resistance index at the upper part of the blast furnace in the actual machine test was investigated.
Here, the ventilation resistance index K at the top of the blast furnace was calculated from the following equation.
^{_{K = ((P 1/98}} ) 2 - (P 2/98) 2) / V 1.7 × 10 6
P ₁ (kPa): average pressure 7.5 m below the stock line, P ₂ (kPa): average pressure of the top gas, V (Nm ³ / min): top gas.

The result of the actual machine test is shown in FIG.
As shown in FIG. 6, when the moisture content of the yard sintered ore is less than 1.0 mass%, the ventilation resistance index at the upper part of the blast furnace changes even if the charging speed v (t / s) of the ore raw material 2a is decreased. There wasn't. On the other hand, when the moisture content of the yard sintered ore is 1.0 mass% or more, when the charging speed v (t / s) of the ore raw material 2a is reduced to 1.05 t / s or less, the remarkable upper portion of the blast furnace A reduction in the airflow resistance index was observed.

Here, considering the influence of the furnace diameter d (m) of the blast furnace 6 on the drying speed, the furnace diameter d (m) of the blast furnace increases without changing the charging speed v (t / s) of the ore raw material 2a. In such a case, it is considered that the layer thickness of the ore raw material 2a deposited in the blast furnace 6 is reduced and the drying rate is increased. Therefore, it is considered that the ore raw material charging speed v (t / s) threshold at which the drying accelerating effect is exerted increases as the furnace diameter of the blast furnace 6 increases.
For example, in the case shown in FIG. 6 described above, if the charging speed v (t / s) of the ore raw material 2a is reduced to 1.05 t / s or less, a drying acceleration effect can be obtained. The threshold value of (t / s) is 1.05 t / s. The furnace diameter d (m) of the blast furnace 6 at this time is 11.4 m.

Here, assuming that the apparent bulk density of the ore raw material 2 a is 2.0 t / m ³ , the ore raw material 2 a is 1.05 (t / s) ÷ 2.0 (t / m ³ ) into the blast furnace 6. /Π(11.4(m)/2) ² = 5.1 × 10 ⁻³ (m / s) Even if the furnace diameter of the blast furnace 6 is changed, the speed of 5.1 × 10 ⁻³ (m / s) which is the threshold value does not change. Therefore, for example, when the furnace diameter of the blast furnace 6 is 13 m, the threshold value of the charging speed v (t / s) of the ore raw material 2a is 5.1 × 10 ⁻³ (m / s) × 2.0 (t / m ³ ) × π (13 (m) / 2) ² = 1.35 (t / s).

Thus, it is considered that the threshold value of the charging speed v (t / s) of the ore raw material 2a increases in proportion to the square of the furnace diameter d (m) of the blast furnace 6. When the proportionality constant α is obtained, when the furnace diameter d (m) of the blast furnace 6 is 11.4 m, the threshold value of the charging speed v (t / s) of the ore raw material 2a is 1.05 t / s. It is calculated that α = 1.05 (t / s) /11.4 (m) ² = 0.008 (t / s · m ² ).
Therefore, the threshold value of the charging speed v (t / s) of the ore raw material 2a is 0.008 (t / s · m ² ) × d ² (m ² ), and the ore raw material 2a is supplied to the furnace port of the blast furnace 6. When the diameter is d (m), the charging chute 5 from the furnace port of the blast furnace 6 at a charging speed v (t / s) of 0.008 (t / s · m ² ) × d ² (m ² ) or less. If it puts in, drying drying effect will be acquired.

When the ore raw material 2a is charged into the charging chute 5 at a charging speed v (t / s) less than 0.0030 (t / s · m ² ) × d ² (m ² ), Although the dust emission promotion effect by the promotion of drying is high, the charging time of the ore raw material 2a becomes long and the drop ratio is reduced, so the ore raw material 2a is reduced to 0.0030 (t / s · m ² ) × d ² ( It is preferable to feed the charging chute 5 at a charging speed v (t / s) of m ² ) or higher.

Using the actual machine shown in FIG. 1, each of a blast furnace 6 having an internal volume of 5153 m ³ and a furnace diameter of 11.4 m, and a blast furnace 6 having an internal volume of 5500 m ³ and a furnace diameter of 12.0 m, The self-sintered yard, the sinter sinter and the lump ore were cut out from (not shown), stored in the furnace top bunker 1, put in the charging chute 5, and deposited in the blast furnace 6.
The charging amount of the ore raw material 2a was determined from the tapping ratio and the coke ratio, and was in the range of 95 to 100 t.

The tilt angle θ of the charging chute 5 is adjusted to an angle of 0.5 r when the ore raw material 2a falls at a furnace radius r, and then the tilt angle θ is increased sequentially for each turn. After the drop position of the raw material 2a reached 0.9r, the tilt angle θ was sequentially decreased for each turn, and the ore raw material 2a was adjusted to have a drop position of 0.5r in the final turn.
The number of turns of the charging chute 5 when the ore raw material 2a was charged into the charging chute 5 was set, and the opening of the flow rate adjusting gate 3 was adjusted accordingly. For example, in Comparative Example 1, the turning speed of the charging chute 5 is 10 rpm, and the opening of the flow rate adjusting gate 3 is such that the ore 96t can be cut out from the furnace top bunker 1 while the charging chute 5 turns 10 times. Adjusted. The test results are shown in Table 1.

The yard sintering ratio indicates a mass ratio (mass%) of the yard sintered ore to the total mass of the ore raw material. The moisture during yard sintering indicates a mass ratio (mass%) of moisture contained in the yard sintered ore with respect to the total weight of the yard sintered ore.
In Examples 1-3, 0.008 (t / s · m ² ) × d ² (m ² ) = 1.04 t / s or less with respect to the furnace diameter d (m) = 11.4 m of the blast furnace 6. The charging chute 5 is charged at an input speed v (1.00 in the first embodiment, 0.90 in the second embodiment, 0.80 in the third embodiment) (t / s). For this reason, the charging speed of the ore raw material 2a to the charging chute 5 can be reduced, and the charging time of the ore raw material 2a can be lengthened. This increases the time for the yard sintered ore with a high water content to contact the high temperature furnace gas on the raw material deposition surface 7 in the blast furnace 6, promotes drying with the high temperature furnace gas, and increases the ventilation resistance at the top of the blast furnace. The index improved to 1.21 or less.

In Examples 4-6, 0.008 against the furnace diameter d (m) = 12.0m blast ^{6 (t / s · m 2} ) × d 2 (m 2) = 1.15t / s or less Is charged into the charging chute 5 at a charging speed v (1.10 in the fourth embodiment, 1.00 in the fifth embodiment, 0.90 in the third embodiment) (t / s). For this reason, the charging speed of the ore raw material 2a to the charging chute 5 can be reduced, and the charging time of the ore raw material 2a can be lengthened. This increases the time for the yard sintered ore with a high water content to contact the high temperature furnace gas at the raw material deposition surface 7 in the blast furnace 6, promotes drying with the high temperature furnace gas, and increases the coke ratio (kg / kg). t): Even if the amount of coke relative to the amount of brewing was reduced, the ventilation resistance index at the top of the blast furnace was improved to 1.15 or less.

On the other hand, in Comparative Examples 1 and 2, 0.008 (t / s · m ² ) × d ² (m ² ) = 1.04 t with respect to the furnace diameter d (m) = 11.4 m of the blast furnace 6. It is charged into the charging chute 5 at a charging speed v higher than / s (1.60 in comparative example 1, 1.19 in comparative example 2) (t / s). For this reason, the charging speed of the ore raw material 2a to the charging chute 5 was fast, and the charging time of the ore raw material 2a was short. For this reason, the time for the yard sintered ore with a high water content to contact the high-temperature furnace gas on the raw material deposition surface 7 in the blast furnace 6 is short, and the drying acceleration effect is insufficient. For this reason, in order to make the ventilation resistance index at the upper part of the blast furnace the same level as in Examples 1 to 3, the coke ratio (kg / t) is made larger than those in Examples 1 to 3 (in Comparative Example 1, 355 kg / t, compared with In Example 2, it was 354 kg / t).

Further, in Comparative Examples 3 to 4, 0.008 (t / s · m ² ) × d ² (m ² ) = 1.15 t / s with respect to the furnace diameter d (m) = 12.0 m of the blast furnace 6. Is charged into the charging chute 5 at a high charging speed v (1.80 in Comparative Example 3, 1.20 in Comparative Example 2) (t / s). For this reason, the charging speed of the ore raw material 2a to the charging chute 5 was fast, and the charging time of the ore raw material 2a was short. For this reason, the time for the yard sintered ore with a high water content to contact the high-temperature furnace gas on the raw material deposition surface 7 in the blast furnace 6 is short, and the drying acceleration effect is insufficient. For this reason, in order to make the ventilation resistance index at the upper part of the blast furnace the same level as in Examples 4 to 6, the coke ratio (kg / t) is set to be larger than that in Examples 4 to 6 (in Comparative Example 3, 357 kg / t, compared with Example 4 required 356 kg / t).

DESCRIPTION OF SYMBOLS 1 Furnace top bunker 2a Ore raw material 2b Coke 3 Flow control gate 4 Vertical chute 5 Charge chute 6 Blast furnace 7 Raw material deposition surface 10 Cylindrical container 11 Bottom part 12 Opening 13 Sintered ore

Claims (1)

A raw material charging method for a bell-less blast furnace in which raw coke and ore raw material are sequentially layered, wherein the ore raw material is charged with a yard sintered ore having a water content of 1 mass% or more. In the raw material charging method of the bell-less blast furnace containing 15 mass% or more with respect to the amount,
When the ore material stored in the furnace top bunker is charged into the charging chute from the furnace port of the blast furnace, when the ore material has a diameter of the furnace port of the blast furnace as d (m), 0.008 ( The raw material charging of the bell-less blast furnace, wherein the charging chute is charged into the charging chute from the blast furnace inlet at a charging speed v (t / s) of t / s · m ² ) × d ² (m ² ) or less. Method.

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