KR102703669B1 - Method for decarbonation of waste refractory materials containing carbon - Google Patents

Abstract

In a method for decarburizing carbon-containing waste refractories for manufacturing recycled refractories from finely divided raw materials that cannot be decarburized by conventional decarburization methods among carbon-containing refractories or waste refractories, the method comprises: a pretreatment process (S10) in which carbon-containing refractories or waste refractories are selected, slag and impurities and gases are removed, and then dried; a fine separation process (S20) in which the pretreated raw materials are crushed to separate raw materials of 15 mm or larger to be regenerated by conventional decarburization methods and raw materials of 15 mm or smaller are separately collected; a fine composition formation process (S30) in which the separately collected raw materials and 10 to 50 wt% of the raw materials are mixed and stirred to form a dough; and the fine composition in the dough state is put into a carbonization tank and heated at a temperature of 1300 to 1600°C for several hours to form pores while evaporating moisture in the fine composition and transmitting oxygen and fire power to carbonize the carbon. It is characterized by significantly improving the regeneration rate and productivity of raw materials by including a decarbonization process (S40) and a regeneration process (S50) of cooling the decarbonized fine particle composition and discharging it from the carbonization tank to obtain regenerated refractory material.

Description

METHOD FOR DECARBONATION OF WASTE REFRACTORY MATERIALS CONTAINING CARBON

The present invention relates to a method for decarburizing carbon-containing waste refractory materials, and more specifically, to a method for decarburizing carbon-containing refractory materials or waste refractory materials used as main materials for furnaces in the steel and iron manufacturing industries, by configuring non-recyclable finely divided raw materials to be recyclable, thereby increasing the regeneration rate and improving productivity.

In general, refractory materials such as refractory bricks with high refractory properties are used as furnace materials in melting furnaces such as blast furnaces and smelting furnaces used in ultra-high temperature work processes such as steelmaking and ironmaking.

Refractory materials are materials that have sufficient mechanical strength and thermal resistance properties even at high temperatures of 1000℃ or higher, and are resistant to erosion and wear from molten metal, slag, and high-temperature gases.

The main raw materials of refractories are natural raw materials such as magnesite, silica, and graphite, or synthetic raw materials such as magnesia and silicon carbide using alumina and spinel. They can be classified into acidic, neutral, and basic refractories depending on their chemical properties. Acidic refractories include quartzite, clay, and silicon carbide refractories, neutral refractories include aluminum oxide, chromium, spinel, and carbon refractories, and basic refractories include magnesia refractories. In particular, magnesia-carbon refractories are carbon-containing refractories manufactured by adding carbon, etc. to magnesia clinker as aggregate. They have excellent heat resistance as well as corrosion resistance against basic slag, and are widely used as refractories for steel furnaces.

Meanwhile, when the above refractory material is used for a certain period of time, various slags and foreign substances are fused on the surface that comes into contact with the molten material, which causes the original high-refractory characteristics to change. Therefore, refractory material that has reached the end of its service life must be discarded and periodically replaced with new refractory material. In this process, more than several thousand tons of waste refractory material is generated each year, resulting in enormous economic losses.

In order to overcome such problems, techniques for regenerating waste refractories are known, for example, Korean Patent No. 10-0908852 discloses a method for producing a high-purity magnesium compound from waste magcarbon refractory, including the steps of crushing waste magcarbon refractory, reacting the crushed waste magcarbon refractory with a strong acid and then filtering it to separate the filtrate, and stirring the filtrate while reacting it with a base to produce a magnesium compound.

As another example, Korean Patent No. 10-1105437 discloses a method for regenerating waste magcarbon refractories, including the steps of removing a deteriorated layer on a working surface of waste magcarbon refractories that have been used as refractory bricks, the step of crushing the waste magcarbon refractories from which the deteriorated layer has been removed, the step of selecting waste magcarbon refractories having a particle size of 1 to 25 mm from the crushed waste magcarbon refractories, and the step of heating the waste magcarbon refractories to a temperature of 1100°C or higher in an oxidizing atmosphere and maintaining the temperature for 1 hour or longer to perform decarburization.

Korean Patent No. 10-0908852 (2009.07.22) Korean Patent No. 10-1105437 (January 17, 2012)

In conventional technology, methods such as treatment and aging of impurities, chemical treatment such as strong acid treatment and base reaction, or a method of decarbonizing carbon are applied to regenerate carbon-containing waste refractory materials.

However, it is difficult to derive mechanical and chemical properties equivalent to those of new refractory materials through simple treatment and maturation of impurities as in the past, and chemical treatment also has the problem of making it difficult to effectively remove carbon and impurities that are excessively generated due to scale, etc., generated in waste refractory materials.

Therefore, another conventional technology comprises a method for manufacturing high-purity regenerated refractory by removing and crushing the deteriorated layer of waste refractory and then decarburizing it.

However, if fine particles with a particle size of 15 mm or less, which are generated in large quantities during the process of crushing waste refractory, are input into the decarbonization process, they can cause problems such as blocking the gap between the ignition port and the ignition material in the carbonization tank, significantly reducing the carbonization efficiency and causing damage to the device.

Therefore, in the conventional technology, only the waste refractories that have been separated into particle sizes and selected to a certain size are used in the decarbonization process, and the fine particles are virtually impossible to process and are thus left as waste.

Accordingly, the present invention was invented to solve the problems of the prior art as described above.

In a method for decarburizing carbon-containing waste refractory materials for manufacturing recycled refractory materials from finely divided raw materials that cannot be decarburized by conventional decarburization methods among carbon-containing refractory materials or waste refractory materials,

A pretreatment process (S10) for selecting carbon-containing refractory or waste refractory raw materials, removing slag, impurities, and gas, and then drying them;

The above preprocessed raw material is crushed and separated into raw materials of 15 mm or larger for regeneration by a conventional decarbonization method, and a fine separation process (S20) is performed to separately collect raw materials of 15 mm or smaller in particle size.

A process (S30) for forming a fine powder composition by mixing and stirring the separately collected raw materials and 10 to 50% by weight of water of the raw materials into a dough state,

A decarbonization process (S40) in which the above-mentioned fine powder composition in a dough state is put into a carbonization tank and heated at a temperature of 1300 to 1600°C for several hours to evaporate moisture in the fine powder composition, form pores, and carbonize carbon by transmitting oxygen and heat;

It includes a regeneration process (S50) for cooling the above-mentioned decarbonized fine composition, discharging it from the carbonization tank, and obtaining a regenerated refractory material.

In the above-mentioned differentiation process (S20),

Separately collected raw materials with particle sizes of 15 mm or less are crushed and pulverized into uniform particle sizes.

In the above decarbonization process (S40),

By injecting an ignition agent made of a combustible material into the powder composition, it is possible to maintain fire power even in a state containing moisture.

The above igniter is mixed into the fine powder composition, or the igniter and the fine powder composition are alternately laminated in the horizontal direction, or the igniter is inserted into the fine powder composition at a certain interval in the vertical direction so as to be evenly distributed within the fine powder composition.

The above-mentioned ignition material is composed of one or more materials selected from the group including wood chips, sawdust, husks, and waste plastics, thereby achieving the purpose of significantly improving the regeneration rate and productivity.

The present invention provides a method for decarbonizing carbon-containing waste refractory material, which increases the regeneration rate and improves process efficiency by streamlining a series of processes for removing carbon from carbon-containing refractory material or waste refractory material raw materials.

In particular, the present invention has the effect of manufacturing a high-purity, high-quality regenerated refractory material by configuring it so that raw materials in a fine powder state with a particle size of 15 mm or less, which cannot be used in the regeneration process in the prior art and are discarded in large quantities, can be effectively applied to the decarbonization process, thereby minimizing the amount of raw material waste and improving productivity.

Figure 1 is a schematic process flow diagram of a method for decarbonizing carbon-containing waste refractory material according to the present invention.

Hereinafter, the configuration and operation of a preferred embodiment of a method for decarbonizing carbon-containing waste refractory material of the present invention will be described in detail with reference to the attached drawings. In the following description, specific descriptions of parts that can be easily implemented by those skilled in the art may be omitted. In addition, since the following description describes preferred embodiments of the present invention, the present invention is not limited to the following embodiments, and it will be understood that various modifications may be provided within a scope that does not depart from the scope of the present invention.

Figure 1 illustrates a schematic process flow diagram of a method for decarbonizing carbon-containing waste refractory material according to the present invention.

It is noted that the method for decarburizing carbon-containing waste refractory to which the technology of the present invention is applied relates to a technology for increasing the regeneration rate and improving productivity by streamlining a series of processes for removing carbon from raw materials in a finely divided state that cannot be regenerated, among carbon-containing refractory or waste refractory raw materials used as main materials of a furnace.

For this purpose, the carbon-containing waste refractory decarburization method of the present invention comprises a series of processes for manufacturing a finely divided raw material, which is discarded because a conventional decarburization method cannot be applied among carbon-containing refractory or waste refractory raw materials, into a regenerated refractory, and is implemented by a waste refractory regeneration device.

The regeneration device to which the present invention is applied is a device configured to have a plurality of regeneration chambers formed of carbonization tanks and ignition tanks, and to include a supply unit for ignition and maintaining firepower, such as oxygen and air, and is provided to manufacture high-purity regenerated refractory material from which carbon has been removed by regenerating waste refractory raw material powder according to the present invention.

The method for decarbonizing carbon-containing waste refractory material according to the present invention comprises a pretreatment process (S10), a fine separation process (S20), a fine composition formation process (S30), a decarbonization process (S40), and a regeneration process (S50), and is specifically as follows.

The above pretreatment process (S10) is a process of selecting carbon-containing waste refractory raw materials, removing slag, impurities, and gas, and then drying them.

The above pretreatment process (S10) is composed of a selection step, a water treatment step, and a drying step.

In the sorting stage, carbon-containing refractory materials or waste refractory materials are collected, and any slag or chemically eroded areas are physically removed to select only the recyclable portion.

The selected carbon-containing raw materials contain components such as metallic alumina, various phenolic resins, and binders. If metallic alumina is mixed into the regenerated refractory raw materials, it can cause cracks or expansion. If phenolic resin is mixed into the regenerated refractory raw materials, it can significantly reduce the adhesive strength with the binder added during the molding process, causing cracks.

Therefore, through the water treatment step, the materials such as metal alumina, phenol resin, and binder contained in the selected raw material are dissolved and removed through a hydration reaction, thereby emitting carbon dioxide to secure the purity of the raw material. The water-treated raw material is dried to remove moisture and residual gas.

The above-mentioned fine separation process (S20) is a process in which the preprocessed raw material is crushed, raw material of 15 mm or larger is separated for regeneration through a conventional decarbonization method, and raw material of 15 mm or smaller particle size is separately collected.

The above-mentioned fine separation process (S20) separately collects raw materials with particle sizes of 15 mm or less generated in the process of crushing carbon-containing refractory materials or waste refractory materials for regeneration, instead of disposing of them as is. If raw materials with particle sizes of 15 mm or less are directly fed into a carbonization tank as in the prior art, this causes the gap between the ignition port and the ignition material to be blocked, which significantly reduces the carbonization efficiency and causes problems such as damage to the device.

In the above-mentioned fine separation process (S20), separately collected raw materials with a particle size of 15 mm or less are crushed and finely divided into uniform particle sizes, thereby effectively forming a fine composition in the subsequent fine composition formation process (S30) and thereby enabling the decarbonization process (S40) to be performed.

The above-mentioned differential composition formation process (S30) is a process of mixing and stirring the separately collected raw material and 10 to 50 wt% of water of the raw material to form a dough.

In the above-described fine composition forming process (S30), the fine composition is formed by mixing and stirring the raw material and water. The fine composition can be formed by differentiating the water content within the above range depending on the progress of the decarburization process (S40) to be described later. For example, at the initial ignition of the decarburization process (S40), a fine composition mixed with a small amount of water, such as 10 wt% of the raw material, is injected so that the ignition can be smoothly performed, and after the ignition is performed, a fine composition mixed with water, such as 50 wt% of the raw material, is injected so that the pore formation due to the evaporation of moisture can be smoothly performed.

If the water content in the above-mentioned fine particle composition is outside the above range, the moisture may rapidly evaporate in the ultra-high temperature environment of the subsequent decarbonization process (S40), which may hinder the formation of pores or cause problems in which the pores are not evenly distributed.

The above decarbonization process (S40) is a process in which a fine powder composition is introduced into a carbonization tank and heated at a temperature of 1300 to 1600°C for several hours to evaporate moisture in the fine powder composition, form pores, and carbonize carbon by transmitting oxygen and heat through the pores.

In the above decarbonization process (S40), the above fine powder composition containing carbon-containing refractory material or waste refractory material raw material fine powder is introduced into the carbonization tank of the decarbonization device, and the carbon is carbonized and removed from the raw material by inducing a reaction between carbon and oxygen at an ultra-high temperature.

The above decarbonization process (S40) initially ignites the carbonization tank in which the above fine particle composition is introduced and supplies oxygen to ignite it. Once the fine particle composition is ignited, carbonization of the carbon proceeds for several hours while supplying air.

Since the above-mentioned fine powder composition is in a state where ignition does not occur easily due to the moisture contained therein, in the decarburization process (S40), an ignition agent made of a combustible material is injected into the fine powder composition to trigger ignition and maintain the firepower even in a state where moisture is contained.

The above ignition material is composed of one or more selected from the group consisting of wood chips, sawdust, husks, and waste plastic.

In the carbonization tank where the above decarburization process (S40) is carried out, heat is applied from the bottom where the ignition tank is located to the top, so it is difficult for the heat to be evenly transferred to the entire fine powder composition, and in particular, it is not easy to trigger ignition due to moisture contained in the above fine powder composition. Therefore, in the above decarburization process (S40), an ignition agent made of a combustible material is injected into the carbonization tank so as to evenly apply heat to the entire fine powder composition and induce the formation of pores through moisture evaporation.

In the above decarburization process (S40), the ignition agent is mixed into the fine powder composition, or the ignition agent and the fine powder composition are alternately laminated in the horizontal direction, or the ignition agent is inserted into the fine powder composition at a certain interval in the vertical direction so as to be evenly distributed within the fine powder composition.

The above ignition agent is provided in powder or chip form, and the mixing method is applied according to the type of ignition agent and the usage environment. The dispersion rate can be maximized by mixing the ignition agent into the fine powder composition and then adding it to the ignition tank, or the fine powder composition and the ignition agent can be alternately added step by step to the ignition tank, or the ignition agent can be inserted into the ignition tank where the fine powder composition has been added at regular intervals in the vertical direction to further improve the ignition and thermal power sustainment efficiency.

The above regeneration process (S50) is a process of cooling the decarbonized fine particle composition, discharging it from the carbonization tank, and obtaining a regenerated refractory material.

The above regeneration process (S50) is inefficient because it takes a long time to cool the refractory material heated by the long-term decarburization process (S40) by leaving it in a natural state. Therefore, after the decarburization process (S40) is completed, air is supplied to the carbonization tank to condense the raw material and discharge it by separating it from the bottom and walls of the carbonization tank.

The method for decarbonizing carbon-containing waste refractory according to the present invention as described above provides a method for decarbonizing carbon-containing waste refractory by effectively applying a finely divided raw material, which is discarded because a conventional decarbonization method cannot be applied among carbon-containing refractory or waste refractory raw materials in a decarbonization process, to the decarbonization process.

Accordingly, the present invention is expected to have great potential for industrial use because it has the effect of manufacturing high-purity, high-quality recycled refractory materials while minimizing the amount of raw material waste and increasing the regeneration rate, thereby reducing waste disposal costs and contributing to the environment, thereby improving productivity.

S10: Pretreatment process
S20: Differential separation process
S30: Differential Composition Formation Process
S40: Decarbonization process
S50: Regeneration process

Claims (3)

In a method for decarburizing carbon-containing waste refractory materials for manufacturing recycled refractory materials from finely divided raw materials that cannot be decarburized by conventional decarburization methods among carbon-containing refractory materials or waste refractory materials,
A pretreatment process (S10) for selecting carbon-containing refractory or waste refractory raw materials, removing slag, impurities, and gas, and then drying them;
The raw materials that have gone through the pretreatment process (S10) are crushed and separated to be regenerated by a conventional decarbonization method for raw materials larger than 15 mm, and the raw materials with a particle size of 15 mm or less are collected separately and crushed to a uniform particle size in the fine separation process (S20).
A process for forming a fine powder composition (S30) by mixing and stirring the raw material obtained in the fine powder separation process (S20) and 10 to 50 wt% of water of the raw material into a dough state,
The fine powder composition formed in the fine powder composition forming process (S30) is put into a carbonization tank and heated at a temperature of 1300 to 1600℃ for several hours to evaporate moisture in the fine powder composition, form pores, and carbonize carbon by transmitting oxygen and heat (S40).
It includes a regeneration process (S50) for cooling the fine powder composition that has undergone the decarbonization process (S40) and discharging it from the carbonization tank to obtain regenerated refractory material.
In the above-mentioned fine particle composition forming process (S30), the moisture content of the fine particle composition is differentially formed within the range of 10 to 50 wt% depending on the progress of the decarbonization process (S40), so that the ignition is smooth during the initial ignition, and after the ignition is completed, the pores are formed smoothly due to moisture evaporation, and then the fine particle composition is introduced in a dough state.
In the above decarbonization process (S40),
By injecting an ignition agent made of a combustible material into the interior of the powder composition, it is possible to maintain fire power even in a state containing moisture.
A method for decarburizing carbon-containing waste refractory, characterized in that the igniter comprises one or more selected from the group consisting of wood chips, sawdust, wood husks, and waste plastics, and is mixed into a fine powder composition, or the igniter and the fine powder composition are alternately laminated in a horizontal direction, or the igniter is inserted into the fine powder composition at a predetermined interval in a vertical direction so that the igniter is evenly distributed within the fine powder composition. delete delete

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