KR102231653B1 - Charging apparatus charging material for blast furnace and charging method of the same - Google Patents

Abstract

Charging the stacked coke to the blast furnace; Charging sintered ore onto the stacked coke layer formed by the charged stacked coke; And charging the central coke and slag in the central region of the sintered ore layer formed by the charged sintered ore.

Description

Charging device for blast furnace charging and its charging method {CHARGING APPARATUS CHARGING MATERIAL FOR BLAST FURNACE AND CHARGING METHOD OF THE SAME}

The present invention relates to a charging device for a blast furnace and a charging method thereof. More specifically, it relates to a charging device for a blast furnace charge and a charging method for preventing the differentiation of the central coke by charging the slag together with the central coke and increasing the gas utilization efficiency.

Recently, a central charging technology in which only the central coke of confrontation at the center of the blast furnace is charged has been used in most blast furnaces. For this reason, a large amount of reducing gas, that is, CO gas, cannot be used to reduce the sintered ore and is discharged to the center of the blast furnace.

In order to improve the above problems, a technology has been developed to increase the gas utilization rate by reducing the amount of gas discharged without being used for reduction at the center of the blast furnace by charging small sintered ore into the central coke to control the air permeability as shown in FIG.1.

However, as shown in FIG. 2, when the small-grain sintered ore is charged into the central coke, Fe ₂ O ₃ in the sintered ore is reduced by CO gas, _{causing a reaction with coke by CO 2} , which causes differentiation of the central coke It happens. 2 shows the degree of coke differentiation when the sintered ore and coke are mixed. It can be seen that when the central coke and the sintered ore are mixed, the differentiation of the central coke increases.

In this case, since the central coke is differentiated and is replaced with small coke in the lower core of the blast furnace, a problem arises that hinders the function of maintaining liquid permeability in the furnace.

That is, since the central coke is differentiated due to the small sintered ore charged in the center and a large amount of powder is included, coke of a small size and a large amount of powder are introduced into the core, and the coke in the furnace bottom portion can be replaced. In this case, the smooth flow of the molten iron in the furnace is obstructed, so that the molten iron cannot flow to the center, but only flows to the periphery, thereby increasing the temperature of the furnace wall.

Accordingly, it causes a problem of damaging the refractory material of the furnace wall and shortens the life of the blast furnace. Therefore, there is a need to improve the gas utilization rate by controlling the air permeability at the center without differentiation of coke at the center of the blast furnace.

It provides a charging device for a blast furnace charging material and a charging method for a blast furnace that can prevent differentiation of the central coke by charging the slag together with the central coke and increase the gas utilization efficiency.

The charging method for a blast furnace charge according to an embodiment of the present invention includes the steps of charging stacked coke in the blast furnace; Charging sintered ore onto the stacked coke layer formed by the charged stacked coke; And charging central coke and slag in a central region above the sintered ore layer formed by the charged sintered ore.

In the step of charging the sintered ore, the slag may be charged together with the sintered ore.

When the charged coke is 60% by weight or more with respect to the total 100% by weight of the coke charged to the blast furnace, the slag may be charged together.

After the step of charging the stacked coke, the step of forming a mixed layer by charging ore containing the coke and iron ore in a central region above the stacked coke layer.

The slag may include steelmaking slag generated from a converter; And ferronickel slag having a lower basicity (CaO/SiO _{2) than the steelmaking slag.}

The slag may include 50 to 60% by weight of steelmaking slag and 40 to 50% by weight of ferronickel slag with respect to the total 100% by weight of the slag.

The average particle diameter of the slag may be 5 to 20 mm.

The slag may have a basicity (CaO/SiO ₂ ) of 0.8 to 2.0.

In the step of charging the central coke and the slag, the slag may be 10 to 30% by volume with respect to the total 100% by volume of the central coke and the slag.

In the step of charging the central coke and slag, the porosity of the central coke and the central coke layer formed by the slag may be 0.3 to 0.45.

A charging device for a blast furnace charge according to an embodiment of the present invention includes a belt conveyor for transferring the charge to the blast furnace; A coke surge hopper for supplying coke to the belt conveyor; And a slag supply hopper disposed at the rear of the coke surge hopper based on the conveying direction of the charged material and supplying the slag to the belt conveyor.

It may further include a control unit for dropping the slag onto the belt conveyor by controlling the discharge of the coke surge hopper and the slag supply hopper, and dropping the coke onto the dropped slag.

The slag surge hopper may include: a first slag surge hopper for supplying steelmaking slag; And a second slag surge hopper disposed parallel to the first slag surge hopper and supplying ferronickel slag.

The control unit controls the discharge of the first slag surge hopper and the second slag surge hopper to adjust the weight ratio (steel slag: ferronickel slag) of the steelmaking slag and the ferronickel slag to 5:5 to 6:4. I can.

In the case of the charging device for a blast furnace charge according to an embodiment of the present invention, slag is mixed with the central coke, and specifically, steelmaking slag and ferronickel slag are mixed with the central coke and cannot be used for reduction in the center of the blast furnace, and discharged. It is possible to induce the movement of the CO gas to be moved to the middle of the blast furnace radius.

_{As a result, it is expected that ηCO (CO 2} /(CO ₂ +CO), which is the efficiency that CO gas is used for ore reduction in the blast furnace, increases by about 1% or more by being used for the reduction of ore in the middle part where a large amount of ore exists I can.

Therefore, there is an effect of contributing to the reduction of the reducing agent cost required for the production of unit molten iron.

In addition, since the small-grained sintered ore is not mixed and charged into the central coke, and the slag is mixed instead, the coke is not differentiated at the center of the core near the fusion zone, so that the differentiated coke may not flow into the center of the core of the furnace.

Accordingly, the molten iron and the slag flow to the center with good ventilation instead of the periphery of the furnace, so that the temperature of the furnace wall is lowered and the wear of the fireproof material on the furnace wall is not intensified, thereby extending the life of the blast furnace.

1 is a view schematically showing a conventional coke-centered charging technology and coke and gas flow in a blast furnace.
2 is a graph comparing the average values of the degree of differentiation and compressive strength of the central coke when the sintered ore of small particles is mixed and charged to the central coke and the sintered ore of the small particle is not charged.
3 is a view showing a state in which the charge is charged according to the charging method of the charge for the blast furnace according to an embodiment of the present invention.
4 is a view showing a charging device for a blast furnace charge according to an embodiment of the present invention.
5 is a graph comparing the average values of the degree of differentiation of the central coke and the compressive strength of Examples and Comparative Examples according to the present invention.
6 is a graph showing a state of observation of changes in gas utilization rate according to an embodiment of the present invention.

Terms such as first, second and third are used to describe various parts, components, regions, layers and/or sections, but are not limited thereto. These terms are only used to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, a first part, component, region, layer or section described below may be referred to as a second part, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is only for referring to specific embodiments and is not intended to limit the present invention. Singular forms as used herein also include plural forms unless the phrases clearly indicate the opposite. The meaning of “comprising” as used in the specification specifies a specific characteristic, region, integer, step, action, element and/or component, and the presence or presence of another characteristic, region, integer, step, action, element and/or component It does not exclude additions.

When a part is referred to as being "on" or "on" another part, it may be directly on or on the other part, or other parts may be involved in between. In contrast, when a part is referred to as being "directly above" another part, no other part is interposed between them.

Although not defined differently, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

Terms defined in a commonly used dictionary are additionally interpreted as having a meaning consistent with the related technical literature and the presently disclosed content, and are not interpreted in an ideal or very formal meaning unless defined.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art may easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

Blast furnace Charged How to charge

The charging method of the charged material for a blast furnace according to an embodiment of the present invention includes charging the stacked coke to the blast furnace, charging the sintered ore on the top of the stacked coke layer formed of the charged stacked coke, and the charged sintered ore. And charging the central coke and slag in the central region of the upper portion of the sintered ore layer to be formed.

First, in the step of charging the laminated coke, the laminated coke is charged into the blast furnace to form a laminated coke layer.

Coke can be supplied from the coke surge hopper in which coke is stored to the belt conveyor connected to the blast furnace, and charged to the furnace hopper disposed on the upper part of the blast furnace.

Next, in the step of charging the sintered ore, the sintered ore layer is formed by charging the sintered ore on the top of the coke layer stacked inside the blast furnace. Specifically, after the laminated coke layer is formed, a mixed layer in which the laminated coke and ore containing iron ore are mixed may be formed on the laminated coke layer, and a sintered ore layer may be formed thereon.

Specifically, the sintered ore forming the sintered ore layer may be an opposing sintered ore having an average particle diameter of 12 to 50 mm. The opposite sintered ore can be supplied from the surge hopper in which the opposite sintered ore is stored to the belt conveyor, and charged to the furnace hopper disposed on the upper part of the blast furnace.

Next, in the step of charging the central coke and the slag, the central coke and the slag are charged together in a central region above the sintered ore layer inside the blast furnace to form a central coke layer.

The slag can be supplied from the slag surge hopper in which the slag is stored to the belt conveyor connected to the blast furnace, and charged to the furnace hopper disposed at the top of the blast furnace. The central coke and slag charged in the hearth hopper can be charged into the blast furnace through the turning chute connected to the hearth hopper to form a central coke layer.

With respect to the total 100% by volume of the central coke and the slag, the slag may be 10 to 30% by volume. By controlling the content of the slag as described above, it is possible to control the porosity of the central coke layer to prevent differentiation of the central coke and to increase the gas utilization rate. In this case, the porosity of the central coke layer formed by the central coke and the slag may be 0.3 to 0.45.

The central coke layer composed of the central coke and slag is formed in the central area above the sintered ore layer to prevent the differentiation of the central coke, and the CO gas discharged to the center is evenly transferred to the sintered ore layer, increasing the gas utilization rate and reducing the cost Can be reduced. Accordingly, charter costs can be reduced.

Furthermore, since the central flow operation of the molten iron is possible, the temperature of the furnace wall can be stable, thereby solving the problem that the blast furnace furnace condition becomes unstable and the blast furnace life is shortened.

Meanwhile, in the step of charging the laminated coke, slag may be charged together with the laminated coke. Accordingly, slag may be included not only in the central coke layer but also in the stacked coke layer.

When the amount of coke to be charged is 60% by weight or more with respect to the total 100% by weight of the coke charged in the blast furnace, the slag may be charged together. In this way, when the slag is charged together from 60% by weight or more, the effect of uniformly dispersing the CO gas can be expected by appropriately controlling the excessive discharge of the CO gas that has not been discharged to the central part to the middle part. Based on the cross section of the blast furnace, when r is the length from the imaginary center point to the inner wall of the blast furnace in the middle of the cross section, the center portion may be an area from the center point to 0.5 r. The middle portion may be in the range of 0.5r to 0.8r. Accordingly, the central region into which the central coke is charged may correspond to the central portion.

The slag may include steelmaking slag generated from a converter and ferronickel slag having a lower _{basicity (CaO/SiO 2) than steelmaking slag.}

Steelmaking slag includes CaO, SiO ₂ , Al ₂ O ₃ , MgO and T.Fe, and basicity (CaO/SiO ₂ ) may be 2 to 4. The melting temperature may be 1200°C or higher.

Ferronickel slag includes CaO, SiO ₂ , MgO and T.Fe, and the basicity (CaO/SiO ₂ ) may be 0.1 or less. The melting temperature may be 1350°C or higher.

It may include 50 to 60% by weight of steelmaking slag and 40 to 50% by weight of ferronickel slag with respect to the total 100% by weight of the slag. In this case, the total melting temperature of the slag may be about 1300°C. In addition, the slag may have an average particle diameter of 5 to 20 mm, and the slag may have a basicity (CaO/SiO ₂ ) of 0.8 to 2.0.

At this time, the melting point in the blast furnace may be similar to that of the sintered ore. Depending on the operating conditions, the overall melting temperature of the slag can be lowered by increasing the proportion of steelmaking slag with a lower melting temperature. If the melting point is lowered, the CO gas going to the center of the blast furnace can be sent to the fusion zone before softening of the sintered ore, so that the gas utilization efficiency can be improved. In addition, it can achieve stability in the old age.

In some cases, if a lower melting point is required, the melting point may be adjusted to about 1200 to 1250°C using only steel slag.

Next, the small-grain sintered ore layer may be formed by charging the small-grain sintered ore in a peripheral region close to the blast furnace wall on the upper portion of the sintered ore layer. The small grain sintered ore may have an average particle diameter of 5 to 12 mm. Based on the cross section of the blast furnace, when r is the length from the imaginary center point in the cross section to the inner wall of the blast furnace, the blast furnace wall portion may be a region from 0.8r to r.

Blast furnace Charged Charging device

As shown in FIG. 4, the charging device for a blast furnace charge according to an embodiment of the present invention includes a belt conveyor 100 for transferring the charge to the blast furnace 10, and a coke surge hopper for supplying coke to the belt conveyor 100 ( 200) and a slag supply hopper which is disposed at the rear of the coke surge hopper 200 based on the conveying direction of the charged material, and supplies slag to the belt conveyor 100.

Coke and sintered ore are alternately charged in the blast furnace 10 and then burned to produce molten iron. The belt conveyor 100 transfers the charge for the blast furnace 10 toward the blast furnace 10. On the upper part of the blast furnace 10, a road hopper 400 to which the charges transferred through the belt conveyor 100 are charged is disposed, and a turning chute 500 is disposed below the furnace hopper 400 to transfer the charges to the blast furnace ( 10) Can be charged inside.

The furnace hopper 400 is divided into a first furnace hopper 400 in which coke is charged and coke is charged into the blast furnace 10 and a second furnace hopper 400 in which sintered ore is charged and sintered ore is charged into the blast furnace 10. I can.

The coke surge hopper 200 is disposed above the belt conveyor 100, and coke is stored therein to drop coke onto the belt conveyor 100. The slag surge hopper 300 is disposed above the belt conveyor 100, and the slag is stored to drop the slag onto the belt conveyor 100.

When the direction in which the charge is conveyed toward the blast furnace 10 on the belt conveyor 100 is forward, the slag surge hopper 300 may be disposed behind the coke surge hopper 200.

Through a control unit connected to the coke surge hopper 200 and the slag supply hopper, discharge of the coke surge hopper 200 and the slag supply hopper can be controlled.

Specifically, slag is first discharged from the slag surge hopper 300 disposed in the rear, and then coke is discharged on the slag from the coke surge hopper 200 disposed in the front, so that the slag is located below the coke, It may be supplied toward the blast furnace 10 along the belt conveyor 100. Since the sintered ore located below and the coke located above are uniformly mixed with each other while colliding with the surface of the charged material, it is possible to form a stacked coke layer and a central coke layer while coke and slag are evenly mixed.

Specifically, the slag surge hopper 300 is disposed side by side with the first slag surge hopper 300 and the first slag surge hopper 300 supplying steelmaking slag, and the second slag surge hopper 300 supplying ferronickel slag. ) Can be included.

The control unit controls the discharge of the first slag surge hopper 300 and the second slag surge hopper 300 to adjust the weight ratio of the steelmaking slag and the ferronickel slag (steelmaking slag: ferronickel slag) from 5:5 to 6:4. Can be adjusted with

The belt conveyor 100 may further include a sintered ore surge hopper and a small sintered ore surge hopper disposed above the belt conveyor 100 to discharge the sintered ore and the sintered ore respectively.

Hereinafter, specific examples of the present invention will be described. However, the following examples are only specific examples of the present invention, and the present invention is not limited to the following examples.

Example

(1) blast furnace Charged Charging

(Example) Coke surge hopper and slag Coke and slag were discharged from the surge hopper to a belt conveyor, respectively. At this time, the slag was discharged so as to be located under the coke on the belt conveyor. Sintered ore The sintered ore discharged from the surge hopper was transferred to the furnace hopper, and the charged material was charged into the blast furnace using a turning suit.

Coke was charged with slag to form a laminated coke layer at a time when the charged coke was 60% by weight or more with respect to the total 100% by weight of the coke charged in the blast furnace. Thereafter, coke and ore containing iron ore were charged together to form a mixed layer in the central region above the stacked coke layer.

A sintered ore layer was formed by charging opposing sintered ore on the top of the stacked cocos layer and the mixed layer, and a central coke layer was formed in a central area above the sintered ore layer by charging coke and sintered ore together. With respect to the total 100% by volume of the central coke and slag, the slag was charged to 20% by volume. Charges were charged into the blast furnace by repeating the above process.

As for the slag, 60% by weight of steelmaking slag and 40% by weight of ferronickel slag were mixed with respect to the total 100% by weight, and the average particle size of the slag was 10 mm, and (CaO/SiO ₂ ) was 0.83. Components of steelmaking slag, ferronickel slag, and slag mixed in the above ratio are shown in Table 1 below.

Classification (% by weight) basicity CaO SiO ₂ Al ₂ O ₃ MgO T.Fe Melting temperature Steel slag 3.0 45 15 2 9 15 1200℃ Ferronickel slag 0.02 One 55 - 35 8 1350℃ Mixed slag 0.83 26.5 31.8 1.2 19.9 12.1 1300℃

(Comparative Example) Charges were charged under the same conditions as in the above example, but without adding slag, the charges were charged.

(2) Evaluation of the degree of differentiation and compressive strength of the core coke

The degree of differentiation and compressive strength of the central coke according to Examples and Comparative Examples were measured and evaluated. After the reaction was carried out in the furnace to the temperature of the fusion zone, a load softening test (SUL) was performed to perform a slag melting test, and then the degree of coke differentiation and the change in compressive strength were shown in FIG. 5. As shown in FIG. 5, the degree of differentiation of the central coke was better in the case of the Example, and in the case of the average value of the compressive strength, it was found that the Example and the Comparative Example showed almost the same level of results.

(3) Observation of changes in gas utilization rate

When referring to FIG. 6. When the slag is charged into the central coke as in the embodiment, gas discharged between the central coke layer and the mixed layer is suppressed, so that most of the reducing gas moves to a portion where a large amount of ore exists, and the gas utilization efficiency is greatly increased. I could confirm.

The present invention is not limited to the above embodiments and/or embodiments, but may be manufactured in a variety of different forms, and those of ordinary skill in the art to which the present invention pertains change the technical spirit or essential features of the present invention. It will be appreciated that it can be implemented in other specific forms without doing so. Therefore, it should be understood that the embodiments and/or embodiments described above are exemplary in all respects and are not limiting.

10: blast furnace
100: belt conveyor 200: coke surge hopper
300: slag surge hopper 400: road hopper
500: swivel suit

Claims (14)

Charging the stacked coke to the blast furnace;
Charging sintered ore on the stacked coke layer formed by the charged stacked coke; And
Including; charging the central coke and slag in the central region of the upper sintered ore layer formed by the charged sintered ore,
The slag,
Steelmaking slag generated from the converter; And
Ferronickel slag having a lower basicity (CaO/SiO _{2) than the steel slag.} The method of claim 1,
In the step of charging the sintered ore,
Charging method for a blast furnace charging material for charging the slag together with the sintered ore. The method of claim 2,
When the charged coke is 60% by weight or more with respect to the total 100% by weight of the coke charged to the blast furnace, the charging method for a blast furnace charging material is charged together with the slag. The method of claim 1,
After the step of charging the laminated coke,
Charging method for a blast furnace charge, further comprising: forming a mixed layer by charging ore containing the coke and iron ore in a central region above the stacked coke layer. delete The method of claim 1,
The slag,
A method of charging a blast furnace charge comprising 50 to 60% by weight of steelmaking slag and 40 to 50% by weight of ferronickel slag based on 100% by weight of the total amount of the slag. The method of claim 1,
The method of charging the blast furnace charge with an average particle diameter of the slag of 5 to 20 mm. The method of claim 1,
The basicity (CaO/SiO ₂ ) of the slag is 0.8 to 2.0. The method of claim 1,
In the step of charging the central coke and slag,
With respect to the total 100% by volume of the central coke and the slag, the slag is 10 to 30% by volume charging method for a blast furnace charge. The method of claim 1,
In the step of charging the central coke and slag,
The porosity of the central coke layer formed by the central coke and the slag is 0.3 to 0.45. A belt conveyor for transferring the charges to the blast furnace;
A coke surge hopper for supplying coke to the belt conveyor; And
Including; a slag supply hopper disposed at the rear of the coke surge hopper based on the conveying direction of the charged material and supplying the slag to the belt conveyor,
The slag supply hopper,
A first slag supply hopper for supplying steelmaking slag; And
A charging device for a blast furnace charge comprising a; a second slag supply hopper which is disposed parallel to the first slag supply hopper and supplies ferronickel slag. The method of claim 11,
A charging device for a blast furnace charge further comprising a control unit for dropping the slag onto the belt conveyor by controlling the discharge of the coke surge hopper and the slag supply hopper, and dropping the coke onto the dropped slag. delete The method of claim 12,
The control unit,
Charge for a blast furnace to control the discharge of the first slag supply hopper and the second slag supply hopper to adjust the weight ratio of the steelmaking slag and the ferronickel slag (steelmaking slag: ferronickel slag) from 5:5 to 6:4 Water charging device.

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