KR102231654B1 - Fe-CONTAINING BRIQUETTES AND MANUFACTURING METHOD THEREOF - Google Patents

Abstract

The present invention relates to an iron-containing briquette and a method for manufacturing the same.
The method for manufacturing an iron-containing briquette according to an embodiment of the present invention includes preparing an iron-containing mixture by mixing iron-containing sludge and iron-containing dust, preparing an agglomerate by pre-assembling the iron-containing mixture, and mixing the agglomerate, bituminous coal, and a binder. It includes the step of preparing the mixture, aging the mixture, and forming the mixture.

Description

Iron-containing briquette and its manufacturing method {Fe-CONTAINING BRIQUETTES AND MANUFACTURING METHOD THEREOF}

The present invention relates to an iron-containing briquette and a method for manufacturing the same. More specifically, it relates to an iron-containing briquette used in a melt-reduction steelmaking process containing iron-containing sludge and iron-containing dust, and a method of manufacturing the same.

In recent years, as a method for manufacturing molten iron, a melt reduction iron making method that replaces the blast furnace method has been developed.

In this molten reduction iron making method, iron ore is partially reduced by charging pulverized light into the flow reduction furnace, and then the reduced reduced iron discharged from the flow reduction furnace is manufactured into hot compacted iron (HCI) and charged into the melting gasification furnace. To manufacture molten iron. That is, the reduced iron is produced in a lump form by applying pressure to the powdered reduced iron at high temperature, and then supplied to the melting gasifier.

At this time, there are cases where additional iron sources are charged into the melting gasifier, such as when the discharge from the flow reduction furnace is poor, continuous operation in the compacting device is not possible, or when the production of molten iron is to be increased.

On the other hand, by-products generated in the melt-reduction steelmaking process can be largely divided into four types, such as sludge, dust, slag, and waste refractory materials. Among them, sludge and dust are recycled in steel mills or as raw materials for cement production because of the large number of Fe, C, and Ca compounds and Mg compounds. However, since a large amount of dust and sludge cannot be recycled, it is being solidified or incinerated. Therefore, their treatment and recycling are emerging as an important environmental problem in the melt reduction steelmaking process.

In the FINEX process, which is a melt-reduction steelmaking process, fine spectroscopy of 8 mm or less is directly used, and a large amount of ultra-fine iron-containing by-products due to mechanical/reduction differentiation due to the high gas flow rate in the flow furnace and the limitation of cyclone dust collection efficiency in the flow furnace. Phosphorus-containing sludge and iron-containing dust are generated. The main constituents include iron that can be used as an iron source, carbon that can be used as a heat source and reducing agent, and other components such as Ca compounds and Mg compounds that can be used as auxiliary materials. The average particle diameter of iron-containing sludge and iron-containing dust, which are iron-containing by-products from the melt-reduction steelmaking process, is in a very fine state, and the iron-containing sludge treated by the water treatment system process contains about 35% moisture, and the iron-containing dust treated by dry dust collection. Has little moisture.

When the iron-containing sludge and iron-containing dust, which are the iron-containing by-products, are introduced in the form of powder, there is a concern that most of the powdery raw materials are lost due to the strong rising air formed on the upper part of the melting gasification furnace. Accordingly, the iron-containing sludge and the iron-containing dust, which are iron-containing by-products, must be coagulated into a mass and put into the melting gasification furnace. However, even if such agglomeration is introduced, if the briquette is differentiated during the transfer and storage process, or if the briquette is charged to the upper part of the high-temperature melting gasification furnace, it is differentiated again and changes to a powdery form, and most of the raw materials are likely to be lost. Accordingly, there is an urgent need to develop a briquette that can be used as an iron source to replace reduced iron by maintaining a certain shape even when charged into a high-temperature melting gasifier.

A method of manufacturing briquettes by mixing powdered iron and one or more by-products of dust or sludge has been proposed, but this ensures the compressive strength of the briquettes, but when it is impacted during the transfer process, the briquettes are again divided into powder or in a high-temperature melting gasifier. When charged, there is a problem in that briquettes are divided into minutes again due to hot shock.

In addition, a method for manufacturing a carbon material built-in briquette was proposed by mixing an iron ore raw material and a coal raw material to prepare a mixture, forming a briquette by pressure molding, and then firing at 300 to 700°C, but the process is complicated because it has to go through a high-temperature firing process. There is a problem that high energy cost is required.

The present invention is to provide an iron-containing briquette and a method for manufacturing the same. More specifically, it is intended to provide an iron-containing briquette and a method of manufacturing the same used in a melt-reduction steelmaking process containing iron-containing sludge and iron-containing dust.

An iron-containing briquette manufacturing method according to an embodiment of the present invention includes the steps of preparing an iron-containing mixture by mixing iron-containing sludge and iron-containing dust; Pre-assembling the iron-containing mixture to prepare an agglomerate; Mixing the aggregate, bituminous coal, and a binder to prepare a mixture; Aging the mixture; And shaping the mixture.

The moisture content of the iron-containing mixture may be 10 to 20% by weight.

The average particle diameter of the aggregate may be 1 to 5 mm. More specifically, the average particle diameter of the aggregate may be 1 to 4 mm.

The bituminous coal may have a particle diameter of 2 mm or less.

The logarithm maximum fluidity (L_MF) of bituminous coal may be 3 or more.

With respect to the sum of 100 parts by weight of the aggregate and bituminous coal, the bituminous coal may be 6 to 30 parts by weight.

Based on 100 parts by weight of the aggregate and the sum of bituminous coal, the binder may be 4 to 8 parts by weight.

The binder may include natural starch, alpha starch, modified starch, dextrin, jade powder, tapioca powder, wheat powder, rice powder, or a combination thereof.

The binder may contain 70 to 90% by weight of a starch component.

The step of aging the mixture may include heating the mixture to maintain 50 to 100 °C. More specifically, it may include a process of heating the mixture to maintain 70 to 95 ℃.

The step of aging the mixture may include stirring the mixture.

The step of molding the mixture may include a process of pressure molding at a pressure condition of 10 to 30 kN/cm.

The volume of the iron-containing briquette may be 10 to 70 cc.

An iron-containing briquette according to an embodiment of the present invention includes an iron-containing mixture, bituminous coal, and a binder, and includes an aggregate in which the iron-containing mixture is agglomerated, and the average particle diameter of the aggregate is 1 to 5 mm.

The average particle diameter of the aggregate may be 1 to 4 mm.

With respect to the cross section of the briquette, the area of the aggregate having a particle diameter of 1 to 5 mm may be 30 to 80% with respect to the total area of the briquette.

Iron-containing briquettes can be used in melt-reduction steelmaking processes.

According to an embodiment of the present invention, an agglomerate whose particle size is increased by pre-assembling the iron-containing mixture to prepare an iron-containing mixture by mixing iron-containing sludge and iron-containing dust, which is an extremely fine iron-containing by-product generated in the melt-reduction steelmaking process. After manufacturing, the agglomerates are mixed with bituminous coal and a binder having a particle diameter or less to prepare a mixture, and the iron-containing briquettes manufactured by aging and molding the agglomerates maintain a shape of a certain size even when they are charged into a high-temperature melting gasifier. do.

The iron-containing briquette according to an embodiment of the present invention has high cold strength and hot strength.

The iron-containing briquette according to an embodiment of the present invention can be used as an iron source to replace hot compacted iron (HCI) in a melt reduction iron making process. Therefore, when the discharge from the flow reduction furnace is poor, or when continuous operation is not performed in the compacting apparatus of the partial reduced iron, the production of molten iron can be maintained by charging briquettes into the melting gasification furnace.

The iron-containing briquette according to an embodiment of the present invention can be charged to the upper portion of the melting gasification furnace, so that iron-containing sludge or iron-containing dust, which is an iron-containing by-product generated in the melt-reduction steelmaking process, can be recycled, thereby improving the economic efficiency of the melt-reduction steelmaking process. I can make it.

1 is a schematic flowchart of a method of manufacturing an iron-containing briquette according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of an apparatus for manufacturing molten iron using an iron-containing briquette manufactured in FIG. 1.
3 is a schematic view of another apparatus for manufacturing molten iron using the iron-containing briquette manufactured in FIG. 1.
4 is a schematic view of a cross-section of an iron-containing briquette according to an embodiment of the present invention.
5 is a hot strength of an iron-containing briquette according to a change in logarithm maximum fluidity (L_MF) of bituminous coal used in an iron-containing briquette according to an embodiment of the present invention.

In this specification, 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.

In the present specification, when a certain part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

In this specification, the terminology used 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. As used in the specification, the meaning of "comprising" specifies a specific characteristic, region, integer, step, action, element and/or component, and the presence of another characteristic, region, integer, step, action, element and/or component, or It does not exclude additions.

In the present specification, the term "combination of these" included in the expression of the Makushi form refers to a mixture or combination of one or more selected from the group consisting of the constituent elements described in the expression of the Makushi form, and the constituent elements It means to include one or more selected from the group consisting of.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein, but is only defined by the scope of the claims to be described later.

1 is a flowchart sequentially showing a method of manufacturing an iron-containing briquette according to an embodiment of the present invention.

As shown in FIG. 1, in the method of manufacturing an iron-containing briquette according to an embodiment of the present invention, the step of preparing an iron-containing mixture by mixing iron-containing sludge and iron-containing dust (S10), and preparing an aggregate by pre-assembling the iron-containing mixture (S20 ), the agglomerates, bituminous coal, and a binder are mixed to prepare a mixture (S30), aging the mixture (S40), and forming the mixture (S50). In addition, the method for manufacturing an iron-containing briquette according to an embodiment of the present invention may further include an additional process in addition to the suggested processes as needed.

First, in step S10, an iron-containing mixture is prepared by mixing iron-containing sludge and iron-containing dust. Iron-containing sludge is an iron-containing by-product generated in the melt-reduction steelmaking process. Since the iron-containing sludge is treated by a water treatment system process, it has a moisture content of 30 to 50% and is in the form of a cake.

Since iron-containing dust is treated by dry dust collection, it contains less than 5% moisture.

In one embodiment of the present invention, by appropriately adjusting the mixing ratio of the iron-containing sludge and the iron-containing dust, it is possible to control the moisture of the entire iron-containing mixture.

Specifically, 30 to 60 parts by weight of iron-containing sludge and 70 to 40 parts by weight of iron-containing dust may be mixed with respect to 100 parts by weight of the iron-containing mixture.

In this case, the iron-containing mixture may have a moisture content of 10 to 20% by weight. More specifically, it may have a moisture content of 12 to 17% by weight. If the blending amount of the iron-containing dust is too large and the moisture in the iron-containing mixture is too low, there may be a problem of environmental pollution due to dust generation during transport. In addition, when the amount of the iron-containing sludge is too large and the moisture of the iron-containing mixture is too high, a problem may occur in that a smooth briquette manufacturing operation cannot proceed due to adhesion in the storage bin of the iron-containing mixture. The iron-containing mixture is evaluated as a useful iron-containing resource containing 45 to 55% by weight of the T-Fe component and 5 to 10% by weight of the C component.

Next, in step S20, an aggregate is prepared by pre-assembling the iron-containing mixture. The average particle diameter of the iron-containing mixture is in the state of a very fine powder of 30 µm and has a very large specific surface area. In order to reduce the specific surface area of the iron-containing mixture, an aggregate is prepared by pre-assembling the iron-containing mixture to have an average particle diameter of 1 to 5 mm. The pre-assembly of the iron-containing mixture may be performed using a high-speed mixer or a pelletizer, and by pre-assembling the iron-containing sludge and the iron-containing dust, the strength of the briquette can be improved by reducing the specific surface area.

In this case, the process of adding moisture during the pre-assembly process may be further included. For storage and transportation by mixing iron-containing dust and iron-containing sludge, the moisture content should be low. This is because storage and transportation are smooth when the iron-containing dust and iron-containing sludge are not adhered during the storage and transportation process. In the pre-assembly process, the moisture content is preferably 15 to 20% by weight, and for this, the process of adding moisture in the pre-assembly process may be further included.

The inventors of the present invention are researching in-depth research on a briquette manufacturing method that can be used as an iron source to replace bulk reduced iron in the melt-reduction steelmaking process, and when the briquette is charged to the dome in a melting gasification furnace at 1000° C. If the specific surface area is reduced by pre-assembling iron-containing sludge and iron-containing dust, which are by-products of iron, and when using finely powdered bituminous coal that can combine iron-containing sludge and iron-containing dust, which are by-products of iron, at high temperatures due to the softening and melting properties of coal, , It was confirmed that the iron-containing sludge and the iron-containing dust, which are by-products of iron, are not divided into powder and can be used as an iron source to replace the reduced iron in bulk by maintaining a shape of a certain size.

In other words, if iron-containing sludge and iron-containing dust are pre-assembled, the specific surface area is reduced, and when an iron-containing briquette is manufactured and used by appropriately using bituminous coal, it does not differentiate into powder and maintains a shape of a certain size, replacing bulk reduced iron. Since it can be used as an iron source, it has the advantage of improving the economics of the melt-reduction steelmaking process.

The aggregate produced in step S20 may have an average particle diameter of 1 to 5 mm. If the average particle diameter of the aggregate is too small, there may be a problem in that the amount of binder is increased or sufficient strength is not secured due to a large specific surface area, and if it is too large, the pre-assembly time may be too long, resulting in a problem of lowering productivity. Therefore, it is possible to prepare an aggregate having the size of the average particle diameter described above.

More specifically, it may have an average particle diameter of 1 to 4 mm.

More specifically, it may have an average particle diameter of 2 to 4 mm.

More specifically, it may have an average particle diameter of 1 to 3 mm.

In this case, in the present specification, "particle diameter" means the diameter of the sphere, assuming a sphere having the same volume as the particle.

Next, in step S30, a mixture is prepared by mixing the aggregate, bituminous coal, and a binder.

With regard to bituminous coal, coal can be classified in a number of ways. For the classification of coal, a criterion of degree of coalification can be used. The degree of coalification refers to a process in which volatile matter of plants decreases and the amount of fixed carbon increases according to changes in time, pressure, and temperature in the basement. Coal can be classified as follows according to the degree of coalification. That is, coal is a carbon content (dry ash free basis) of about 60% or less peat, about 60 to 70% lignite, about 70 to 75% sub-bituminous coal, about 75 to 85% depending on the degree of coalification. It is divided into bituminous coal, which is about 85 to 94% anthracite.

On the other hand, coal may be classified into low-oil, heavy-duty coal, and high-oil coal depending on whether or not it has a fluidity. The flow rate is a value representing the rotational speed of the Kisera plastometer stirring rod and is usually expressed in DDPM (Dial Division per Minute) units, and one rotation is calculated as 100 DDPM. The logarithm maximum fluidity (L_MF) of the maximum fluidity (MF), which is the very high value of DDPM, can be used as the flow rate characteristic value of coal. Bituminous coal with high fluidity has a wide range of softening and melting of coal during drying, so it has good blendability. When the coal is heated, it exhibits thermal softening and flow phenomena around 350 to 400° C., and the coal particles combine with each other to expand due to the generation of pyrolysis gas, and shrinkage due to solidification at around 450 to 500° C. As for the fluidity, the coal is heated by 3℃ per minute, and the softening and melting area and range of the coal particles are measured by the rotational force of the Kisera plastometer stirring rod. In general, coal with a logarithm maximum fluidity (L_MF) index of less than 3, which indicates the fluidity characteristic, is classified as low petroleum coal, coals above 3 and less than 4 are classified as heavy oil coal, and coals above 4 are classified as high oil coal. have.

By mixing bituminous coal having a high fluidity in step S30, it is possible to combine iron-containing sludge and iron-containing dust, which are iron-containing by-products, even at high temperatures due to softening and melting properties. When bituminous coal is properly used, iron-containing sludge and iron-containing dust, which are iron-containing by-products, are not divided into powder and can be used as an iron source to replace bulk reduced iron by maintaining a shape of a certain size.

The bituminous coal in step (S30) is in the form of a fine powder, it is preferable that the particle diameter is 2 mm or less. The smaller the particle size of the bituminous coal, the higher the specific surface area of the bituminous coal, and it is possible to provide sufficient coal capable of binding iron-containing by-products having little bonding force at high temperatures.

It is preferable that the logarithm maximum fluidity (L_MF) of bituminous coal in step S30 is 3 or more. At this time, the fluidity index can be evaluated by the fluidity test method (Giselle Plastometric method) of the coal type test method (KS E 3710), as described above, and coal with a high fluidity index may be evaluated at the time of drying. The softening and melting range of coal is wide, so it has good blendability. In the case of coal having a too low fluidity index, the softening and melting range of the coal particles at a high temperature decreases, so that the iron-containing by-products cannot be sufficiently bonded, and thus the hot strength of the iron-containing briquettes may decrease. Therefore, in the present invention, 3 or more Bituminous coal with the highest flow rate (L_MF) of commercially available water can be used.

The bituminous coal in step (S30) may include 6 to 30 parts by weight, more specifically 10 to 30 parts by weight, and more specifically 10 to 20 parts by weight, based on 100 parts by weight of the aggregate and the total bituminous coal. Can be included. In this case, if the content of bituminous coal is too small, the hot strength of the iron-containing briquette may be rather degraded because the aggregates cannot be sufficiently bonded at high temperature. If the content of bituminous coal is too high, the bituminous coal is excessive than necessary. There is a concern that the amount of aggregates may be reduced by being added in a manner. Accordingly, the content of bituminous coal is adjusted within the above-described range.

Meanwhile, the aggregate may be 70 to 94 parts by weight, more specifically 70 to 90 parts by weight, and more specifically 80 to 90 parts by weight, based on 100 parts by weight of the aggregate and the bituminous coal. However, the content of the aggregate is determined by excluding the content of the above-described bituminous coal, and is not limited thereto.

On the other hand, the above-described pre-assembled iron-containing mixture, that is, the aggregate and bituminous coal alone may not provide the necessary bonding force for agglomeration at room temperature in some cases. In this case, a binder may be further included in addition to the aggregate and bituminous coal.

In this case, the binder may be included in 4 to 8 parts by weight based on 100 parts by weight of the aggregate and bituminous coal. If the content of the binder is too small, the room temperature strength cannot be secured, and the iron-containing briquettes may be damaged in the process of transporting or storing the iron-containing briquettes. As a result, due to the strong rising air that exists in the dome of the melting gasifier. Loss may occur, and if the content of the binder is too large, there is no longer an effect of enhancing the strength. Accordingly, an appropriate content range of the binder may be limited to 4 to 8 parts by weight based on 100 parts by weight of the aggregate and bituminous coal.

The binder in step S30 may be natural starch, alpha starch, modified starch, dextrin, jade powder, tapioca powder, wheat powder, rice powder, or a combination thereof.

Starch is a kind of carbohydrate extracted from nature, and it is a natural polymer in which several glucoses are bound by a glucoside bond. Starch is present in the form of granules for energy storage in all green plants, and is abundantly contained in corn, cassava, wheat, potatoes, and rice. Starch is composed of two components: amylose and amylopectin. Both are polysaccharides, and glucose is bound in straight chains and spirals in amylose, and glucose is bound in twigs in amylopectin. Although the ratio of the two is different depending on the type of plant, starch is usually composed of 20 to 30% amylose and 70 to 80% amylopectin. The starch particle structure was shown, in which a crystalline region structure in which amylopectin chains are regularly arranged and an amorphous region structure in which amylose chains are irregularly dispersed are sequentially intersected.

Starch does not dissolve in cold water, but it dissolves in a gel form in hot water and becomes a paste. Dissolving does not simply dissolve like sugar or salt, but undergoes a more complicated process of alpha (α) or gelatinization. Starch originally had a semi-crystalline structure. However, when starch is put in hot water, water penetrates through the starch particles, causing the starch particles to swell, eventually destroying the semi-crystalline structure of the starch. At this time, the trapped amylose molecules escape from the starch particles, and as these amylose molecules are connected to each other, the viscosity of the starch solution increases and becomes sticky like a glue. This is a reaction called gelatinization or gelatinization. In general, the higher the amylose content, the easier it is to gelatinize to become a paste. Starch must be gelatinized to function as a binder for iron-containing briquettes.

The binder is in the form of a powder, and the content of the starch component may be 70 to 90% by weight. If the content of the starch component is too small, the mixture cannot be sufficiently bonded, so that the cold strength of the iron-containing briquette may be deteriorated.

The binder may be provided in a powder state. If a powdery binder is used, the flowability of the aggregate, bituminous coal and binder mixture is improved, and uniform iron-containing briquettes can be manufactured. In addition, when a powdery binder is used when manufacturing an iron-containing briquette, the strength of the briquette can be sufficiently secured without going through an additional drying process before use in operation. In addition, the powdery binder is easy to store and transport by minimizing its volume, and there is no need to worry about freezing in winter.

In contrast, when a liquid binder is used, the flowability of the binder, agglomerates and bituminous coal mixture is lowered due to the high moisture content, so that adhesion occurs in the process of manufacturing briquettes, and the mixture is unevenly charged to the molding machine. There is also a phenomenon in which the strength and shape of the briquettes become uneven due to the occurrence of a phenomenon. In addition, since the iron-containing briquettes produced in this way have a high moisture content, a drying process must be additionally performed before charging into the melter to secure the strength of the briquettes, which increases the overall process time and cost, and increases process efficiency. It may also deteriorate. In addition, it is difficult to keep the binder component uniformly due to layer separation of the liquid binder, and because it freezes in winter, storage is not easy.

Next, step (S40) is a step of aging a mixture of aggregates, bituminous coal and a binder. When the agglomerate, bituminous coal, and binder mixture is prepared, the mixture is charged into the body of the aging machine, and the mixture is aged while supplying a heat source to the inside of the aging machine body through an electric heater or steam supply means.

During the aging of the mixture, the environment inside the body may be controlled so that the mixture is maintained at about 50 to 100°C, preferably about 70 to 95°C. If the temperature of the mixture is too high, it takes a lot of energy to increase the temperature of the mixture, which is not desirable in terms of process efficiency.If the temperature of the mixture is too low, the gelatinization reaction of the starch binder does not occur sufficiently, so that an iron-containing briquette having the desired strength is obtained. Difficult to manufacture

In the aging process, the mixture may be stirred using a stirrer. When the mixture is stirred using a stirrer, the temperature of the mixture can be uniformly adjusted as a whole. In addition, in the process of aging the mixture, starch causes a gelatinization reaction and becomes viscous. When the mixture is stirred using a stirrer, the mixture and the stirrer come into contact with each other to generate frictional heat. The frictional heat generated in this way can be used as a heat source to cause a gelatinization reaction of starch together with steam supplied into the body.

When the mixture is aged in this way, a gelatinization reaction occurs in which the starch binder uniformly dispersed in the bituminous coal expands when the temperature inside the body of the aging period increases and changes to a state of high viscosity. As a result, the gelatinized starch binder can significantly improve the cold strength of the iron-containing briquettes produced in the subsequent process by expressing the binding force to the aggregate and bituminous coal.

Next, step S50 is a step of forming the mixture. When the aging process is completed, the mixture is withdrawn from the body of the aging machine and charged into a molding machine to produce an iron-containing briquette. The iron-containing briquette may be prepared by charging the aged mixture between a pair of rollers and then pressing.

At this time, the pressure during the pressure molding is sufficient if the molding pressure of a conventional roll press molding machine is sufficient, and is preferably performed under a pressure condition of 10 to 30 kN/cm. If the pressure is too small, sufficient molding pressure cannot be applied and cold strength cannot be secured, and thus a case of damage may occur in the process of transporting or storing the iron-containing briquettes according to the present invention. There is no strength enhancing effect.

2 schematically shows a molten iron manufacturing apparatus 100 using the iron-containing briquette manufactured in FIG. 1. The structure of the apparatus 100 for manufacturing molten iron of FIG. 2 is for illustrative purposes only, and the present invention is not limited thereto. Accordingly, the apparatus 100 for manufacturing molten iron of FIG. 2 can be modified in various forms.

The molten iron manufacturing apparatus 100 of FIG. 2 includes a melting gasification furnace 10 and a packed bed type reduction furnace 20. In addition, other devices may be included as needed. Iron ore is charged and reduced in the packed bed type reduction furnace 20. The iron ore charged in the packed bed type reduction furnace 20 is made of reduced iron while passing through the packed bed type reduction furnace 20 after being pre-dried. The packed bed type reduction furnace 20 is a packed bed type reduction furnace, and receives reducing gas from the melter gasifier 10 to form a packed bed therein.

The iron-containing briquettes and coal briquettes manufactured by the manufacturing method of FIG. 1 are charged into the melter gasifier 10. A dome 101 is formed on the upper part of the fusion gasification furnace 10. That is, a wider space is formed than other parts of the melter gasifier 10, and there is a high-temperature reducing gas. On the other hand, since char provides air permeability, a large amount of gas generated in the lower part of the melting gasifier 10 and reduced iron supplied from the packed-bed reduction furnace 20 make the coal-filled bed in the melter gasifier 10 easier and more uniform. Can pass.

In addition to the above-described iron-containing briquettes and coal briquettes, bulk carbon material or coke may be charged into the melting gasification furnace 10 as necessary. An air vent 30 is installed on the outer wall of the melter gasifier 10 to inject oxygen. Oxygen is blown into the coal-filled bed to form a combustion zone. Coal briquettes can be burned in a combustion zone to generate reducing gas.

That is, the iron ore charged to the packed bed type reduction furnace 20 and the iron-containing briquette charged to the melting gasification furnace 10 need to be distinguished.

3 schematically shows a molten iron manufacturing apparatus 200 using the iron-containing briquette manufactured in FIG. 1. The structure of the apparatus 200 for manufacturing molten iron of FIG. 3 is for illustrative purposes only, and the present invention is not limited thereto. Therefore, the molten iron manufacturing apparatus 200 of FIG. 3 can be modified in various forms. The structure of the molten iron manufacturing apparatus 200 of FIG. 3 is similar to that of the molten iron manufacturing apparatus 100 of FIG. 2, so the same reference numerals are used for the same parts, and detailed descriptions thereof are omitted.

As shown in FIG. 3, the molten iron manufacturing apparatus 200 includes a melting gasification furnace 10, a fluidized bed reduction furnace 22, a reduced iron compression device 40, and a compressed reduced iron storage tank 50. Here, the compressed reduced iron storage tank 50 may be omitted.

The manufactured iron-containing briquettes and coal briquettes are charged into the melting gasification furnace 10. Here, the coal briquettes charged into the melter gasifier generate a reducing gas in the melter gasifier 10, and the generated reducing gas is supplied to the fluidized bed type reduction furnace 22. Powdered iron ore is supplied to a plurality of reduction furnaces 22 having a fluidized bed, and is made of reduced iron while flowing by the reducing gas supplied from the melting gasifier 10 to the fluidized bed type reduction furnace 22. The reduced iron is compressed by the reduced iron compression device 40 and then stored in the compressed reduced iron storage tank 50. The compressed reduced iron is charged from the compressed reduced iron storage tank 50 together with the iron-containing briquettes and coal briquettes manufactured in the melting gasification furnace 10 and melted in the melting gasification furnace 10.

4 is a schematic view of a cross-section of an iron-containing briquette according to an embodiment of the present invention.

The iron-containing briquette includes an iron-containing mixture, bituminous coal and a binder. Since the iron-containing mixture, bituminous coal, and the binder have been described in the method of manufacturing the iron-containing briquette, redundant descriptions will be omitted.

As shown in FIG. 4, the iron-containing briquette 300 according to an embodiment of the present invention includes an aggregate in which an iron-containing mixture is agglomerated (310). The portion 320 excluding the aggregate is a matrix portion in which the non-aggregated iron-containing mixture, bituminous coal, and binder are uniformly dispersed.

On the other hand, in an embodiment of the present invention, the aggregate means particles aggregated with only an iron-containing mixture without a binder and bituminous coal, and the particle diameter is 0.1 mm or more.

The agglomerates may be partially destroyed in steps (S30) and (S40), but most of them remain.

The average particle diameter of the aggregate 310 may be 1 to 5 mm, which is the same as the reason for limiting the particle diameter of the aggregate in the method of manufacturing an iron-containing briquette described above.

With respect to the cross section of the briquette, the area of the aggregate having a particle diameter of 1 to 5 mm may be 30 to 80% with respect to the total area of the briquette. If the area occupied by the aggregate is too small, it may be difficult to ensure adequate briquette strength. If the area occupied by the agglomerates is too large, the content of bituminous coal and the binder becomes small, and it may likewise be difficult to ensure adequate briquette strength.

As can be seen in Figure 4, the aggregates exist in the iron-containing briquette. The aggregate may have a sphere or various shapes, and the area of the aggregate having a particle diameter of 1 to 5 mm may be 30 to 80% with respect to the total area of the briquette.

5 shows the hot strength of the iron-containing briquette according to the change in logarithm maximum fluidity (L_MF) of bituminous coal used in the iron-containing briquette according to an embodiment of the present invention.

The hot strength was measured to determine the degree of differentiation of briquettes occurring inside the melter gasifier. To this end, about 1Kg of briquettes at room temperature was put into a cylindrical reactor having a diameter of 280mm under heating conditions set at 800°C and nitrogen inert atmosphere, and then the cylindrical reactor was rotated for 20 minutes at a rotation speed of 2 rpm. The hot strength of iron-containing briquettes was measured with the ratio of confrontation of char having a particle diameter of 10 mm or more of iron-containing briquettes.

As can be seen in FIG. 5, as the logarithm maximum fluidity (L_MF) of bituminous coal used in the iron-containing briquette increases, the hot strength of the iron-containing briquette increases as shown in Equation 1 below.

[Equation 1]

Iron-containing briquette hot strength = 7.18 X (L_MF of bitumen coal) + 53.77

As the hot strength of iron-containing briquettes increases, it is judged that the degree of differentiation of briquettes decreases. When the logarithm maximum fluidity (L_MF) of bituminous coal used in iron-containing briquettes is 3 or more, it shows excellent hot strength of iron-containing briquettes.

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

Example

Example 1-1

An agglomerate was prepared by pre-assembling an iron-containing mixture in which iron-containing sludge and iron-containing dust were mixed so that the average particle diameter was 1.1 mm in a high-speed rotary mixer (Eirich). 6 parts by weight of a corn starch binder based on 100 parts by weight of the main component of an iron-containing briquette consisting of 15 parts by weight of bituminous coal having 85 parts by weight of the prepared aggregate and 15 parts by weight of bituminous coal having a logarithm maximum fluidity (L_MF) index of 4.1 and less than 1 mm in particle diameter. Mix evenly for minutes. The mixture was again put into an aging machine having a temperature range of 75 to 95°C, and aged and mixed for 15 minutes. The aged mixture was pressed with a pressure of 20 kN/cm in a roll press to prepare a 25 cc pillow-shaped briquette.

Example 1-2

Pre-assembled so that the average particle diameter of the iron-containing mixture was 1.8 mm, and the remaining conditions were to prepare a briquette in the same manner as in Example 1-1.

Example 1-3

Pre-assembled so that the average particle diameter of the iron-containing mixture was 2.7 mm, and the remaining conditions were prepared in the same manner as in Example 1-1 to prepare a briquette.

Example 1-4

Pre-assembled so that the average particle diameter of the iron-containing mixture was 3.5 mm, and the remaining conditions were to prepare a briquette in the same manner as in Example 1-1.

Example 1-5

Pre-assembled so that the average particle diameter of the iron-containing mixture was 0.7 mm, and the remaining conditions were prepared in the same manner as in Example 1-1 to prepare a briquette.

Example 2

An agglomerate was prepared by pre-assembling an iron-containing mixture in which iron-containing sludge and iron-containing dust were mixed so that the average particle diameter was 1.9 mm in a high-speed rotary mixer (Eirich). 6.5 parts by weight of a corn starch binder based on 100 parts by weight of the main component of an iron-containing briquette composed of 85 parts by weight of the prepared aggregate and 15 parts by weight of bituminous coal with a logarithm maximum fluidity (L_MF) index of 4.6 or less and a particle diameter of 1 mm or less. Mix evenly for minutes. The mixture was again put into an aging machine having a temperature range of 75 to 95°C, and aged and mixed for 15 minutes. The aged mixture was pressed with a pressure of 20 kN/cm in a roll press to prepare a 25 cc pillow-shaped briquette.

Example 3

An agglomerate was prepared by pre-assembling an iron-containing mixture in which iron-containing sludge and iron-containing dust were mixed so that the average particle diameter was 2.0 mm in a high-speed rotary mixer (Eirich). 6.5 parts by weight of a corn starch binder based on 100 parts by weight of the main component of an iron-containing briquette composed of 85 parts by weight of the prepared aggregate and 15 parts by weight of bituminous coal having a logarithm maximum fluidity (L_MF) index of 3.8 and a particle diameter of 1 mm or less. Mix evenly for minutes. The mixture was again put into an aging machine having a temperature range of 75 to 95°C, and aged and mixed for 15 minutes. The aged mixture was pressed with a pressure of 20 kN/cm in a roll press to prepare a 25 cc pillow-shaped briquette.

Example 4

An agglomerate was prepared by pre-assembling an iron-containing mixture in which iron-containing sludge and iron-containing dust were mixed so that the average particle diameter was 1.8 mm in a high-speed rotary mixer (Eirich). 6.5 parts by weight of a corn starch binder based on 100 parts by weight of the main component of an iron-containing briquette composed of 85 parts by weight of the prepared aggregate and 15 parts by weight of bituminous coal having a logarithm maximum fluidity (L_MF) index of 3.9 and a particle diameter of 1 mm or less. Mix evenly for minutes. The mixture was again put into an aging machine having a temperature range of 75 to 95°C, and aged and mixed for 15 minutes. The aged mixture was pressed with a pressure of 20 kN/cm in a roll press to prepare a 25 cc pillow-shaped briquette.

Example 5

An agglomerate was prepared by pre-assembling an iron-containing mixture in which iron-containing sludge and iron-containing dust were mixed so that the average particle diameter was 2.0 mm in a high-speed rotary mixer (Eirich). 6.5 parts by weight of a corn starch binder based on 100 parts by weight of the main component of an iron-containing briquette consisting of 20 parts by weight of bituminous coal with 80 parts by weight of the prepared aggregate and 20 parts by weight of bituminous coal having a logarithm maximum fluidity (L_MF) index of 4.1 and a particle diameter of 1 mm or less. Mix evenly for minutes. The mixture was again put into an aging machine having a temperature range of 75 to 95°C, and aged and mixed for 15 minutes. The aged mixture was pressed with a pressure of 20 kN/cm in a roll press to prepare a 25 cc pillow-shaped briquette.

Example 6

An agglomerate was prepared by pre-assembling an iron-containing mixture in which iron-containing sludge and iron-containing dust were mixed so that the average particle diameter was 1.9 mm in a high-speed rotary mixer (Eirich). 6 parts by weight of an alpha starch binder based on 100 parts by weight of the main component of an iron-containing briquette consisting of 15 parts by weight of bituminous coal with 85 parts by weight of the prepared aggregate and 15 parts by weight of bituminous coal having a logarithm maximum fluidity (L_MF) of 4.1 and a particle diameter of 1 mm or less. Mix evenly for minutes. The mixture was again put into an aging machine having a temperature range of 75 to 90°C, and aged and mixed for 10 minutes. The aged mixture was pressed with a pressure of 20 kN/cm in a roll press to prepare a 25 cc pillow-shaped briquette.

Comparative Example 1

Based on 100 parts by weight of the main component of the iron-containing briquette consisting of 85 parts by weight of an iron-containing mixture mixed with iron-containing sludge and iron-containing dust and 15 parts by weight of bituminous coal having a logarithm maximum fluidity (L_MF) of 4.1 and a particle diameter of 1 mm or less. 6 parts by weight of the corn starch binder was uniformly mixed for 3 minutes. The mixture was again put into an aging machine having a temperature range of 75 to 95°C, and aged and mixed for 15 minutes. The aged mixture was pressed with a pressure of 20 kN/cm in a roll press to prepare a 25 cc pillow-shaped briquette.

Comparative Example 2

An agglomerate was prepared by pre-assembling an iron-containing mixture in which iron-containing sludge and iron-containing dust were mixed so that the average particle diameter was 1.8 mm in a high-speed rotary mixer (Eirich). 6 parts by weight of a corn starch binder based on 100 parts by weight of the main component of an iron-containing briquette composed of 85 parts by weight of the prepared aggregate and 20 parts by weight of bituminous coal having a logarithm maximum fluidity (L_MF) of 0.6 and a particle diameter of 1 mm or less. Mix evenly for minutes. The mixture was again put into an aging machine having a temperature range of 75 to 95°C, and aged and mixed for 15 minutes. The aged mixture was pressed with a pressure of 20 kN/cm in a roll press to prepare a 25 cc pillow-shaped briquette.

Comparative Example 3

An agglomerate was prepared by pre-assembling an iron-containing mixture in which iron-containing sludge and iron-containing dust were mixed so that the average particle diameter was 1.4 mm in a high-speed rotary mixer (Eirich). 6.5 parts by weight of a corn starch binder based on 100 parts by weight of the main component of an iron-containing briquette consisting of 5 parts by weight of bituminous coal with 95 parts by weight of the prepared aggregate and 5 parts by weight of bituminous coal having a logarithm maximum fluidity (L_MF) of 4.1 and a particle diameter of 1 mm or less. Mix evenly for minutes. The mixture was again put into an aging machine having a temperature range of 75 to 95°C, and aged and mixed for 15 minutes. The aged mixture was pressed with a pressure of 20 kN/cm in a roll press to prepare a 25 cc pillow-shaped briquette.

Comparative Example 4

An agglomerate was prepared by pre-assembling an iron-containing mixture in which iron-containing sludge and iron-containing dust were mixed so that the average particle diameter was 2.6 mm in a high-speed rotary mixer (Eirich). 6 parts by weight of an alpha starch binder based on 100 parts by weight of the main component of an iron-containing briquette consisting of 15 parts by weight of bituminous coal with 85 parts by weight of the prepared aggregate and 15 parts by weight of bituminous coal having a logarithm maximum fluidity (L_MF) of 4.1 and a particle diameter of 1 mm or less. Mix evenly for minutes. The mixture mixed at room temperature was pressed with a pressure of 20 kN/cm on a roll press to prepare a 25 cc pillow-shaped briquette.

evaluation

Evaluation 1: Measurement of falling fraction

In order to determine the degree of differentiation of briquettes occurring in the process of charging into melt gasification, the falling fraction of briquettes was measured. To this end, 1 hour after the manufacture of iron-containing briquettes, 2 kg of briquettes were freely dropped 8 times at a height of 5 m, and the dropping fraction was measured by the ratio of briquettes having a particle diameter of 6.3 mm or less.

Evaluation 2: Measurement of hot fraction

The hot fraction was measured to determine the degree of differentiation of briquettes occurring inside the melter gasifier. To this end, about 1Kg of briquettes at room temperature was put into a cylindrical reactor having a diameter of 280mm under heating conditions set at 800°C and nitrogen inert atmosphere, and then the cylindrical reactor was rotated for 20 minutes at a rotation speed of 2 rpm. The smaller the degree of hot differentiation of the iron-containing briquette, the better the hot strength, so the hot fraction of the iron-containing briquette was measured with the ratio of char with a particle diameter of 3 mm or less in terms of fine grain ratio.

result

The measurement results of the dropping fraction and hot fraction of the iron-containing briquettes prepared according to Examples 1-1 to 6 and Comparative Examples 1 to 4 are shown in Table 1 below.

Mixing ratio of iron-containing briquettes Briquette manufacturing conditions ferment Iron briquette strength Iron-containing mixture
(Part by weight) Bituminous coal
(Part by weight) bookbinder
(Part by weight) Aggregate
Average particle diameter
(mm) Bituminous coal
Flow rate
(L_MF) Maturation Falling fraction
(%) Hot fraction
(%) Example 1-1 85 15 6 1.1 4.1 O 13.3 18.3 Example 1-2 85 15 6 1.8 4.1 O 10.0 14.2 Example 1-3 85 15 6 2.7 4.1 O 3.1 6.3 Example 1-4 85 15 6 3.5 4.1 O 3.7 12.8 Example 1-5 85 15 6 0.7 4.1 O 18.1 26.0 Example 2 85 15 6.5 1.9 4.6 O 10.3 9.8 Example 3 85 15 6.5 2.0 3.8 O 10.2 15.3 Example 4 85 15 6.5 1.8 3.9 O 12.1 9.9 Example 5 80 20 6.5 2.0 4.1 O 6.9 9.4 Example 6 85 15 6 1.9 4.1 O 3.7 10.5 Comparative Example 1 85 15 6.5 - 4.1 O 39.3 69.3 Example 7 85 15 6 1.8 0.6 O 14.3 23.7 Example 8 95 5 6.5 1.4 4.1 O 14.5 65.5 Comparative Example 2 85 15 6 2.6 4.1 X 34.7 6.7

Referring to Table 1, the falling fraction of the iron-containing briquettes prepared according to Examples 1-1 to 1-4 and Examples 2 to 6 is 15% or less, and the hot fraction is 20% or less. It can be seen that it represents the strength.

However, in the case of Example 1-5, it was confirmed that the particle diameter of the aggregate was too small during pre-assembly, so that the dropping fraction and the hot fraction were partially deteriorated.

The falling fraction of the iron-containing briquettes prepared according to Comparative Example 1 was higher than 15%, and the hot fraction was also higher than 20%. It exceeded 20%. The iron-containing briquette prepared according to Comparative Example 2 had a good hot fraction, but a falling fraction exceeded 15%. In this way, if the dropping fraction or hot fraction is high, it is not suitable to be used as an iron source to replace hot compacted iron (HCI) in a melting gasification furnace.

The present invention is not limited to the above 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, other specific forms without changing the technical spirit or essential features of the present invention. It will be appreciated that it can be implemented with. Therefore, it should be understood that the embodiments described above are illustrative and non-limiting in all respects.

10: melting gasification furnace 20: packed bed type reduction furnace
22: fluidized bed reduction furnace 30: punggu
40: reduced iron compression device 50: compressed reduced iron storage tank
100, 200: molten iron manufacturing apparatus 101: dome
300: iron-containing briquette 310: aggregate
320: metrics

Claims (19)

Mixing the iron-containing sludge and the iron-containing dust to prepare an iron-containing mixture;
Pre-assembling the iron-containing mixture to prepare an agglomerate;
Preparing a mixture by mixing the aggregate, bituminous coal, and a binder;
Aging the mixture; And
Shaping the mixture;
Including,
The average particle diameter of the agglomerate is 2 to 4 mm in the method for producing an iron-containing briquette.
The method of claim 1,
The water content of the iron-containing mixture is 10 to 20% by weight of the iron-containing briquette manufacturing method.
delete delete The method of claim 1,
The bituminous coal has a particle diameter of 2 mm or less.
The method of claim 1,
The logarithm maximum fluidity (L_MF) of the bituminous coal is 3 or more.
The method of claim 1,
With respect to the sum of 100 parts by weight of the aggregate and bituminous coal, the bituminous coal is 6 to 30 parts by weight of the iron-containing briquette manufacturing method.
The method of claim 1,
With respect to the sum of 100 parts by weight of the aggregate and bituminous coal, the binder is 4 to 8 parts by weight of the iron-containing briquette manufacturing method.
The method of claim 1,
The binder is an iron-containing briquette manufacturing method comprising natural starch, alpha starch, modified starch, dextrin, jade powder, tapioca powder, wheat powder, rice powder, or a combination thereof.
The method of claim 1,
The binder is a method for producing an iron-containing briquette containing 70 to 90% by weight of a starch component.
The method of claim 1,
The step of aging the mixture,
Iron-containing briquette manufacturing method comprising the step of heating the mixture to maintain 50 to 100 ℃.
The method of claim 11,
The step of aging the mixture,
Iron-containing briquette manufacturing method comprising the step of heating the mixture to maintain 70 to 95 ℃.
The method of claim 1,
The step of aging the mixture,
Iron-containing briquette manufacturing method comprising the step of stirring the mixture.
The method of claim 1,
The step of shaping the mixture,
A method of manufacturing an iron-containing briquette comprising a process of pressure molding at a pressure condition of 10 to 30 kN/cm.
The method of claim 1,
The volume of the iron-containing briquette is 10 to 70 cc of the iron-containing briquette manufacturing method.
Including an iron-containing mixture, bituminous coal and a binder,
The iron-containing mixture comprises agglomerated aggregates,
The average particle diameter of the aggregate is an iron-containing briquette of 2 to 4 mm.
delete The method of claim 16,
With respect to the cross-section of the briquette, the area of the aggregate having a particle diameter of 1 to 5 mm is 30 to 80% of the total area of the briquette.
The method of claim 16,
The iron-containing briquette is an iron-containing briquette that is used in a melt-reduction steelmaking process.

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