KR100718581B1 - Substituting for pig iron and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a pig iron substitute and a method for manufacturing the iron-by-product by aggregating the organic binder and the cement-based inorganic binder alone or mixed to steelmaking by-products.

The pig iron substitute manufactured by the present invention can be used as a substitute for pig iron, but by aggregating the steel by-products to prevent dusting of raw materials, thereby solving environmental problems, eliminating a decrease in recovery rate due to dust generation, and mixing carbon-based particles. Maximize the reducing effect of iron.

The manufactured pig iron substitute is not only able to freely adjust the shape and size according to the application, but also prevent the side effects of pig iron scattered by hot air or lost by the dust collector in the furnace is a very useful invention in the steel industry.

Pig iron substitute, inorganic binder, organic binder, iron, steel slag, cement, steel by-product

Description

Pig iron substitute and its manufacturing method {SUBSTITUTING FOR PIG IRON AND MANUFACTURING METHOD THEREOF}

The present invention relates to a pig iron substitute and a method for manufacturing the same, and more particularly, by adding an organic and / or inorganic binder to the grain-based steel by-products to agglomerate the steel by-products to prevent dusting of raw materials to solve environmental problems. It is to provide a pig iron substitute and a method of manufacturing the same to remove the reduction in recovery rate due to dust generation and to maximize the reducing effect of the iron component by mixing the carbon-based particles.

Pig iron is a type of iron produced directly from iron ore and is also called an alloy cast iron having a carbon content of 1.7% or more in iron.

In recent years, the manufacturing method of the blast furnace which is mainstream in pig iron manufacture is gradually exhausting the high quality coking coal for blast furnace which is a manufacturer of coke used as a fuel and a reducing agent. In addition, due to the lack of coke, demand for CO ₂ gas reduction due to global warming, and strengthened regulations on SOx and NOx generated in the coke process and sintering plant, it is increasingly restricted in its implementation.

In addition, the blast furnace process requires a pretreatment process such as a sintering or pelletizing process, since the raw material is agglomerated in order to secure air permeability and prevent re-dusting in the blast furnace.

In order to solve the problems of the conventional blast furnace process, U.S. Patent No. 4,978,387 uses a powder raw material directly without pretreatment to reduce to a fluidized bed reduction furnace or a bubble fluidized bed reduction furnace and finally melt reduction in a melt reduction reactor. A process has been proposed. More specifically, a method of sending the pre-reduced ore preliminarily reduced in the preliminary reduction reactor to the melt reduction reactor using gas, as described above, when injecting the powder by gas, the gas and powder blowing in the melt reduction reactor Charged powder raw materials are dusted by the gas, not only to cause the loss of raw materials, but also to increase the energy as a whole because the heat of heating of the gas at room temperature for consumption is additionally consumed. In addition, in the case of redusting of the powder due to gas blowing, dust is introduced into the preliminary reduction reactor together with the gas, which causes clogging of the dispersion plate in the preliminary reduction reactor or adheres to the fluidized bed furnace wall, which causes enormous disruption in equipment and operation time. It was also.

In order to prevent dust of pig iron in the melt reduction process as described above, various techniques for compacting powders have been developed.

Until now, the proposed method of compacting powder is based on the use of oxide-based compounds on the premise of adding water, such as bentonite, as a coagulant. By re-cooling and charging, not only is the process complicated, but there is also a problem in that the waste of energy is large. In addition, these compounds, which are used as flocculants for the compaction of powders, require not only elevated temperature energy in the process but also contain impurities such as S and P, which may adversely affect the quality of the molten iron produced during use. will be.

The present inventors have developed a technology that can be used as a substitute for pig iron by recycling steel by-products.

The present invention has been made to solve the above-mentioned problems, an object of the present invention is to add the organic binder and cement-based inorganic binder alone or mixed to the steel by-products to harden the grains to maximize the reduction effect of the iron component In addition, to provide a pig iron substitute and a method of manufacturing the same to prevent dusting of the raw material.

In order to solve the above technical problem, the pig iron substitute according to an aspect of the present invention is to add the organic binder and cement-based inorganic binder alone or mixed to the steel by-products to compact the steel by-products.

The steel by-products may preferably be any one or more of iron, steel, sludge or steel dust.

The grained iron is preferably used to crush the steel slag, and then to increase the content of iron components by charity spectroscopy.

The pig iron substitute is preferably 2 to 20 parts by weight of the mixture of the organic binder and the inorganic binder with respect to 100 parts by weight of the steel by-products.

The organic binder is preferably any one or more selected from the group consisting of molasses, starch, glue and organic adhesive.

The cement-based inorganic binder may be preferably any one or more selected from the group consisting of slag cement, aluminum cement, CSA cement and clinker.

Portland cement, preferably as carbon-based particles, in the steelmaking by-product. It is also possible to add graphite, carbon black, coke, pitch, tar and steel dust whose main component is carbon alone or in combination, more preferably the carbon-based based on 100 parts by weight of the steel by-products. 5-30 parts by weight of particles are further added.

It is also possible to add 10 to 50 parts by weight of the sole or mixture of silicon or aluminum, preferably 100 parts by weight of the steelmaking by-product.

The particle size of the bulk iron wire substitute is preferably 25 to 300 mm.

According to another aspect of the present invention, there is provided a method of manufacturing a pig iron substitute, which includes: 1) grinding steel slag, and 2) charifying the pulverized steel slag to a high iron content. Preparing granules, 3) adding the organic binder of the substrate and the inorganic binder of the cement series of the substrate to the granules alone or by mixing, and 4) mixing and mixing the granulated granules in a molding machine. And adding to necrosis.

In the third step, preferably, graphite, carbon black, coke, pitch, tar, and iron dust whose main component is carbon may be further added alone or as a carbon-based particle. Do.

In the third step above, it is also possible to further add solely or a mixture of silicon or aluminum.

After the fourth step, it is also preferable to further include the step of curing the aggregated pig iron substitute.

Hereinafter, the present invention will be described in more detail.

Pig iron substitute according to an embodiment of the present invention by adding the organic binder and the cement-based inorganic binder alone or mixed to the iron by-products to compact the steel by-products.

First, the steel by-products used as raw materials of the present invention will be described.

Steel by-products are by-products generated during the production of iron in the steelmaking process, and can be classified into steel slag, steel sludge, and steel dust according to the particle size and water content. Slag derived), steelmaking sludge, and steelmaking dust can be used.

Among them, steel sludge and steel dust are small in diameter but high in water content, and thus can be used in the present invention through a drying process, but steel slag is low in water content and is used by grinding and charity spectroscopy.

Hereinafter, the granulation used for this invention is demonstrated.

The steel slag, which is a raw material of the iron used in the present invention, may be used without any limitation as long as it contains iron content of a certain content or more as a by-product of the steelmaking process. The steel slag is crushed by a grinder. The mill used at this time is not limited in kind, but may use a rod mill or a hammer mill, which is a kind of a grinding kneader.

The crushed steel slag is reacted with a magnet to extract only the iron component. This is called charity spectroscopy. If the content of iron contained in the first steel slag is about 40 to 50% by weight, the pulverized steel slag subjected to the charity spectroscopy contains about 70 to 98% by weight of iron, which is called granulation. do. The particle size of the said grain iron is about 0.8-8 mm normally.

Next, an organic binder added to the steelmaking by-products will be described.

The organic binder of the present invention reacts with the steel by-products to bulk the steel by-products. Melting the pig iron substitutes agglomerated by the organic binder in an electric furnace or blast furnace can easily burn fuel in the furnace, thereby saving fuel as well as melting and eliminating them. Since the slag is not a source of slag, the recovery rate of the iron component from the injected pig iron substitute is increased.

On the other hand, the organic binder usable in the present invention is not limited in kind as long as it is easily burned on a furnace, and preferably any one or more selected from the group consisting of molasses, starch, glue and an organic adhesive may be used. .

Next, the weapon binder will be described.

The inorganic binder of the present invention reacts with the steel by-products to bulk the steel by-products. As the inorganic binder of the present invention, cement series is preferably used. The cement may be preferably any one or more selected from the group consisting of portland cement, slag cement, aluminum cement, CSA cement and clinker. In particular, since the clinker contains little sulfur, it can be widely used in steelmaking.

On the other hand, the inorganic binder of the present invention is significantly improved compared to the organic binder, the strength of the aggregated pig iron substitute material is not only very easy to transport and storage, but also not easily broken during the process of adding to the furnace (dust) Has the advantage of not occurring. However, since the inorganic binder is not easily burned on the furnace, the recovery rate of iron in the injected pig iron substitute is lower than that of the organic binder. Therefore, in the present invention, the organic binder and the inorganic binder can be used alone or in combination according to their purpose and use.

Meanwhile, the pig iron substitute of the present invention may elastically control the content of iron, organic binder and inorganic binder included according to its use and purpose, but preferably, the mixture of the organic binder and the inorganic binder may be based on 100 parts by weight of iron. It is good that it is 2-20 weight part. If the amount is less than 2 parts by weight, the addition amount is too small to effectively perform the bulking operation, and if it exceeds 20 parts by weight, the content of the binder is too high, the content of the iron component is lowered and the economical efficiency is low.

The pig iron substitute according to another embodiment of the present invention may further add carbon-based particles to impart reducing power. Iron by-products often form iron oxide when reacted with air, in which case the iron content is reduced. In the present invention, carbon-based particles are added to impart reducing power to the iron oxide. The carbon-based particles are not limited as long as they can reduce iron oxide as a carbon-based compound, but preferably graphite, carbon black, coke, pitch, tar and steel dust whose main component is carbon alone It is also possible to add further by mixing. In particular, in the case of steel dust whose main ingredient is carbon, it is very suitable for environmental preservation in that steel by-products can be recycled.

The pig iron substitute according to another embodiment of the present invention may further promote the dissolution of the pig iron substitute on the furnace by adding 10 to 50 parts by weight of silicon or aluminum alone or a mixture. The aluminum is preferably added in the form of aluminum dross, and excellent in reducing energy to reduce the iron when added, as well as metal aluminum can be used as a part of 6000 ~ 7000 ㎉ / ㎏ fuel, excellent energy saving .

The particle size and shape of the pig iron substitute manufactured by the above configuration and method can be elastically adjusted according to the use. In the case of the particle diameter can be used without limitation as long as it does not scatter on the blast furnace, such as dust collector and hot air, but preferably 25 to 300 mm is mainly produced. The shape can be manufactured in various shapes such as cube, spherical shape, and oval shape, and can be extruded by manufacturing a mold having a desired shape.

The pig iron substitute of the present invention can be used in both an electric furnace and blast furnace, it is possible to appropriately adjust the ratio of the compositions added to the present invention according to the purpose of use and use.

According to another aspect of the present invention, there is provided a method of manufacturing a pig iron substitute, which includes: 1) pulverizing steel slag, and 2) charifying the pulverized steel slag. Manufacturing high granulation, 3) adding the organic binder of the substrate and the inorganic binder of the cement-based substrate alone or by mixing, and then mixing the granulation, and 4) vibrating the mixed granulation in a molding machine. Aggregating by applying pressure.

In step 1), the steel slag is crushed by a grinder. The mill used at this time is not limited in kind, but may be a rod mill or a hammer mill, which is a kind of grinding kneader. The particle diameter of the steel slag to be crushed is preferably 0.8 to 8 mm.

In step 2), the iron component is extracted through the magnet to the steel slag pulverized in the step 1) to prepare the grain iron. The strength (magnet density) of the magnet can be used without limitation as long as it can extract iron components. The iron content of the prepared iron in this step is higher than the iron content of conventional steelmaking slag and occupies approximately 70 to 98% by weight.

In step 3), the organic binder and the cement-based inorganic binder are added alone or mixed to the granules prepared in step 2), and then mixed. The organic binder is preferably at least one selected from the group consisting of molasses, starch, glue and organic adhesive, the cement-based inorganic binder is preferably portland cement, slag cement, aluminum cement, CSA Any one or more selected from the group consisting of cement and clinker can be used. In this case, preferably 2 to 20 parts by weight of the organic binder and the inorganic binder alone or a mixture is added based on 100 parts by weight of the steel by-products.

Thereafter, the added iron and the organic and / or inorganic binder are mixed. In this case, as long as it can effectively mix the granulation and binder, regardless of the type, mixing temperature and mixing time of the mixer, preferably in a ribbon mixer at room temperature for 0.2 to 5 minutes, the type and ratio of the binder mixed Depending on the mixing time and elasticity can be adjusted.

Meanwhile, preferably, graphite, carbon black, coke, pitch, tar and iron dust whose main component is carbon are added alone or in combination to further reduce the iron component in step 3). It can increase.

On the other hand, preferably in step 3), it is also possible to promote the dissolution of the pig iron substitute on the furnace by further adding silicon or aluminum alone or mixed.

In step 4), the mixed granules are subjected to vibration and pressure in a molding machine to compact the granules mixed with the binder. The molding machine generally has no limitation as long as it can block the grains of iron, but preferably a conventional vibration compression molding machine, compression molding machine, extrusion molding machine or vibration molding machine is used, and considering the content of the kind of binder or the like added. The strength of the vibration and the pressure may be elastically adjusted, but more preferably, the vibration strength of 2,000 to 4,000 Hz and / or the strength of the pressure of 200 to 700 ton / cm 2 may be molded at room temperature.

In addition, it may further comprise the step of curing the hardened pig iron substitute prepared through the step 4). In this case, if the moisture content of the pig iron substitute to be manufactured can maintain 2 to 15%, regardless of the drying method and drying time, preferably curing for 15 to 80 ℃ at about 8 to 180 hours.

Hereinafter, the present invention will be described in more detail with reference to Examples. This example is intended to explain the present invention more specifically through the most preferred embodiments, and the scope of the present invention is not limited to these examples.

Example 1

Steel slag was pulverized in a rod mill for 30 minutes to prepare steel slag having a particle diameter of 2 mm. The pulverized steel slag was magnetically spectroscopically mounted on a conveyer belt with a magnetic separator to prepare a grained iron having an iron content of 75% by weight or more. 5 parts by weight of molasses as an organic binder and 10 parts by weight of coke as carbon-based particles were added to 100 parts by weight of the prepared granular iron, followed by mixing for 3 minutes in a ribbon mixer at room temperature. After the vibration compression molding machine, vibration compression molding was performed at a vibration intensity of 3,000 Hz and a pressure of 500 tons / cm 2, and then bulked into a rectangular parallelepiped shape of 70 * 80 * 100 mm in width, length and height. After curing at room temperature for about 50 hours to prepare a pig iron substitute.

Example 2

Instead of adding an organic binder, 5 parts by weight of clinker is added as an inorganic binder. Except that was carried out in the same manner as in Example 1 to prepare a pig iron substitute.

Example 3

Steel sludge having a water content of about 30% was dried in a rotary kiln for about 1 hour to maintain a water content of about 4%. 5 parts by weight of molasses as an organic binder, 10 parts by weight of coke as carbon-based particles and 15 parts by weight of aluminum dross were added to 100 parts by weight of the dried steel sludge, followed by mixing for 3 minutes in a ribbon mixer at room temperature. Thereafter, vibration compression molding was carried out using a vibration compression molding machine at a vibration intensity of 3,000 Hz and a pressure of 500 tons / cm 2 to mass a cylinder having a height of 150 mm and a diameter of 50 mm. After curing at room temperature for about 50 hours to prepare a pig iron substitute.

Example 4

Steel dust with a water content of about 20% was dried in a rotary kiln for about 30 minutes to maintain a water content of less than 4%. 15 parts by weight of CSA cement was added as an inorganic binder to 100 parts by weight of the steel dust, followed by mixing for 3 minutes in a ribbon mixer at room temperature. Thereafter, vibration compression molding was carried out at a vibration intensity of 3,000 Hz and a pressure of 500 tons / cm 2 to form a cylindrical shape having a height of 150 mm and a diameter of 50 mm. After curing at room temperature for about 80 hours to prepare a pig iron substitute.

As described above, the hardened pig iron substitute according to the present invention is added to the steel by-products, the organic binder and the cement-based inorganic binder alone or mixed to increase the reducing power of the iron component, as well as when added to the smelting furnace As it has high value. In addition, the pig iron substitute of the present invention can change the degree and strength of the iron content in accordance with the intended use by adjusting the dosage of the organic and / or inorganic binder appropriately. In addition, carbon-based particles may be added to increase the reducing power of the iron component.

The manufactured pig iron substitute is not only able to freely adjust the shape and size according to the application, but also prevent the side effects of pig iron scattered by hot air or lost by the dust collector in the furnace is a very useful invention in the steel industry.

While the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the invention.

Claims (14)

2 to 20 parts by weight of the organic binder and one or more inorganic binders selected from the group consisting of portland cement, slag cement, aluminum cement, CSA cement, and clinker based on 100 parts by weight of steel, silicon or aluminum alone or Pig iron substitute, characterized in that the steel by-products are compacted by adding 10 to 50 parts by weight of the mixture. The method of claim 1, The iron by-product is iron pig substitute, characterized in that any one or more of iron, steel sludge or steel dust. The method of claim 2, The grain iron is the pig iron substitute, characterized in that to increase the content of the iron component by crushing the steel slag, charity. delete The method of claim 1, Wherein the organic binder is molten iron, starch, glue and any one or more selected from the group consisting of an organic adhesive. delete The method of claim 1, Said pig iron substitute, characterized in that the steel-based by-product is further added alone or mixed with graphite, carbon black, coke, pitch, tar and iron dust whose main component is carbon. The method of claim 7, wherein Said pig iron substitute material, characterized in that 5 to 30 parts by weight of the carbon-based particles further added to 100 parts by weight of steel by-products. delete The method of claim 1, Said wrought iron substitute is a particle size of 25 ~ 300 mm. In the method of manufacturing a pig iron substitute material, 1) grinding the steel slag; 2) charitatively spectroscopy the crushed steel slag to obtain grain iron having a high content of iron; Manufacturing; 3) the organic binder and portland cement, slag in 100 parts by weight of the prepared iron Selected from the group consisting of cement, aluminum cement, CSA cement and clinker Mixing any one or more inorganic binders to add 2 to 20 parts by weight, alone or a mixture of silicon or aluminum, and 10 to 50 parts by weight; And 4) aggregating the mixed grains by applying vibration and pressure in a molding machine Pig iron substitute manufacturing method characterized in that it comprises a. The method of claim 11, The pig iron, characterized in that the addition of iron or steel alone or mixed with graphite, carbon black, coke, pitch (pitch), tar and the main component is carbon alone as carbon-based particles in the third step. Method of manufacturing substitutes. delete The method of claim 11, After the fourth step, the method of manufacturing the pig iron substitutes further comprising the step of curing the aggregated pig iron substitutes.