KR20180062528A - Carbon composite iron oxide briquette comprising the carbon composite comprising volatile matter, and reduction method thereof at oxidation atmosphere - Google Patents

Abstract

The present invention relates to a carbon composite briquette comprising a carbon composite comprising a volatile matter and a reduction method thereof in an oxidation atmosphere, wherein the carbon composite briquette does not include a binder such that bonding agent cost can be reduced. In addition, an amount of iron ore can be increased as much as an amount of the bonding agent that is reduced. Operation efficiency within a furnace is improved such that production costs can be reduced. The reduction method is a reduction method for manufacturing a partial reduced iron by reducing the carbon composite briquette in an atmosphere supplied with oxygen.

Description

[0001] The present invention relates to a carbonaceous embedded briquette containing a carbonaceous material containing a volatile material and a carbonaceous composite iron oxide briquette comprising the carbonaceous material,

The present invention relates to a carbonaceous internal briquetting material containing a carbonaceous material containing a volatile substance and a reducing method thereof in an oxidizing atmosphere.

The steel industry is one of the oldest industries that has come along with the development of mankind as a core industry that supplies basic materials to all industries such as automobile, shipbuilding, home appliance, and construction. Steel mills, which play a pivotal role in the steel industry, manufacture molten iron, which is a molten iron by using iron ore and coal as raw materials, and then manufacture steel from these to supply them to each customer.

At present, about 60% of the world's iron production is produced from the blast furnace, which was developed from the 14th century. The blast furnace method is a method of manufacturing molten iron by adding sintered iron ore and cokes produced from bituminous coal as raw materials, blowing hot air and reducing iron ore to iron.

Since the blast furnace process, which is a type of molten iron production facility, requires a raw material having a certain level of strength or more and a particle size capable of ensuring ventilation in the blast furnace, as described above, it is used as a fuel and a reducing agent Carbon source, which depends on coke treated with specific cokes, and the iron source is mainly dependent on a series of masses and sintered ores that have undergone the process.

Accordingly, since the present blast furnace method necessarily involves a raw material pre-treatment facility such as a coke making facility and a sintering facility, it is necessary not only to construct an additional facility other than the blast furnace, There is also a problem that the investment costs are consumed in a large amount and the manufacturing cost is rapidly increased.

Also, in order to smooth the flow of reducing gas in the blast furnace, the sintered ore which made the iron ore into a lump state and the coke which is made into the lump state by charging the analytical carbon are charged. However, the contact area of the reducing gas per unit volume of the sintered ore in the bulk state is extremely small as compared with the iron ore, and even after the reduction in the blast furnace is completed, the contact area with the carbon is small and it is difficult to permeate the carbon into the reduced iron. Therefore, the sintered ores have a high melting point, so they require a lot of energy to melt and have a fundamental problem that the production speed of the molten iron is slow.

To solve these problems, in the case of direct reduced iron (DRI), which has conventionally developed and used direct reduced iron (DRI), a process of manufacturing a pellet of a minute iron ore and inducing a reduction in a rotary hearth furnace Has come.

Korean Patent No. 10-1375071 discloses a briquetting method and a manufacturing method thereof. More particularly, the present invention relates to a briquetting apparatus including sodium carbonate, which is a desulfurizing agent for desulfurizing molten steel in a converter, and briquettes containing slag and binder Wherein the slag contains at least one of Al ₂ O ₃ , SiO ₂ , CaO, FeO and MgO, and Na ₂ O ₃ , and the Na ₂ O ₃ is contained in an amount of 1 to 20 wt% The briquettes of the present invention have been disclosed.

Korean Patent Laid-Open Publication No. 10-2014-0065555 discloses a pellet built-in pellet capable of securing room-temperature strength without firing using molasses as a binder, thereby enabling high-efficiency blast furnace operation, and a manufacturing method thereof And more particularly to a carbonaceous material-containing pellet comprising 75 to 79 parts by weight of iron ore, 19 to 20 parts by weight of coke, and 2 to 6 parts by weight of molasses, and a method for producing the same.

However, the briquettes include a binder for chemically bonding the carbonaceous material and the iron raw material to increase the viscosity and tackiness, thereby causing an inefficient operation of the blast furnace due to an increase in the basicity of the briquet, resulting in an increase in production costs.

In addition, such a process must proceed in an inert atmosphere to exhibit a reduction ratio of 95% or more, so that the production is limited to a mass production of 15 to 500 thousand tons per year.

On the other hand, when partially reduced iron is partially used in the blast furnace, it is possible to contribute to the stabilization of the sulfur content by drastically reducing the reduction ratio in the blast furnace, improving the productivity, and improving the air permeability in the high temperature portion of the blast furnace.

Accordingly, the inventors of the present invention have developed a method for reducing the production cost of the carbonaceous internal briquettes by developing a carbonaceous internal briquette which does not contain a binder capable of lowering the production cost of the carbonaceous internal briquettes and reducing the carbonaceous internal briquettes in an oxidizing atmosphere Thereby completing the present invention.

Korean Patent No. 10-1375071 Korean Patent Publication No. 10-2014-0065555

SUMMARY OF THE INVENTION

Containing briquettes containing a carbonaceous material containing a volatile substance and a method for reducing the carbonaceous briquettes in an oxidizing atmosphere.

In order to achieve the above object,

Iron ore and 10 to 20% of the weight of the iron ore, wherein the carbonaceous material comprises a volatile substance.

In addition,

Manufacturing the carbonaceous built-in briquettes (step 1); And

(Step 2) of reducing the carbonaceous built-in briquettes in the reduction furnace,

Wherein the reduction is performed in a gas atmosphere containing 10 to 20% O ₂ and CO ₂ gases, respectively.

Further,

A partially reduced iron produced by the above reduction method is provided.

The carbon-bearing briquettes of the present invention include a carbonaceous material containing a volatile substance, so that there is an advantage that a binder is not separately added. That is, since the carbonaceous material itself has tackiness, a binder is not required separately when mixing the carbonaceous material and the iron ore. Therefore, it is possible to increase the amount of iron ore in the briquettes embedded in the carbonaceous material by the amount of the reduced amount, and the inefficient operation of the blast furnace is not caused by the increase of the basicity of the briquet, There is an advantage that the production cost can be reduced.

In addition, the method for reducing the briquettes embedded in a carbonaceous material according to the present invention is a method in which the briquettes embedded in the carbonaceous material are partially reduced in an oxygen atmosphere. When the blended briquettes are used in a blast furnace, the reduction ratio in the blast furnace is significantly reduced, productivity is improved, Which can contribute to the stabilization of the agar.

1 is a schematic view showing a reducing furnace according to an embodiment of the present invention,
FIG. 2 is a photograph showing a shape according to a reduction temperature of a carbon-bearing briquette of the present invention,
3 is a scanning electron microscope (SEM) photograph showing the shape of the carbon-bearing briquette according to the reduction time of the present invention,
FIG. 4 is a graph showing a change in strength according to reduction temperature and time of the carbon-bearing briquettes of the present invention,
FIG. 5 is a graph showing a change in exhaust gas according to reduction temperature and time of the carbon-bearing briquettes of the present invention,
FIG. 6 is a graph showing the amount of unreacted carbon and the amount of oxygen according to the reduction temperature and time of the carbon-bearing briquettes of the present invention,
FIG. 7 is a graph showing the reduction rates of the carbon-bearing briquettes according to the present invention,
8 is a graph showing the metallization ratios of the carbonaceous built-in briquettes according to the present invention at a reduction temperature and time.

The present invention

Iron ore and 10 to 20% of the weight of the iron ore, wherein the carbonaceous material comprises a volatile substance.

Hereinafter, the carbon-bearing briquettes of the present invention will be described in detail.

The carbonaceous built-in briquettes of the present invention include iron ores and carbonaceous materials.

The carbonaceous built-in briquettes are made of carbonaceous materials to reduce iron ore more easily and economically. That is, the carbonaceous material serves as a reducing agent for reducing the iron ores contained in the briquettes. This is advantageous in that the price is lower than that of the natural gas used as the reducing agent in the past and the geographical restriction of the plant location is also small.

At this time, the iron ore may be hematite, but is not limited thereto, and the carbonaceous material may include at least one of coal and carbon dust generated in a steel process.

The carbon-bearing briquettes of the present invention preferably include iron ores and carbonaceous materials of 10 to 20% of the weight of the iron ores. This is to appropriately reduce the iron ores contained in the briquettes, and also to allow the partially reduced iron produced after the reduction to have appropriate strength.

If the content of the carbonaceous material is less than 10% of the weight of the iron ore, the reduction of the iron ores contained in the briquet may not occur sufficiently. If the content of the carbonaceous material exceeds 20% There is a possibility that the strength of the partially reduced iron produced after the reduction may be lowered as the carbon content increases.

Meanwhile, the carbonaceous material preferably contains a volatile substance.

This is for the purpose of not further including a binder in the carbonaceous built-in briquettes.

Conventionally, in order to produce the carbonaceous material-containing briquettes, a binder which plays a role of enhancing the viscosity and the tackiness for inducing the chemical bonding between the carbonaceous material and the iron ores is included. As a result, the basicity of the briquetting increases and the production cost . On the other hand, in the case of the carbonaceous built-in briquettes of the present invention, there is an advantage that the carbonaceous material-containing briquettes containing the carbonaceous material including the volatile substance having viscosity can be manufactured without containing the binder. Therefore, since the carbon-bearing briquettes of the present invention include a binder, there is no problem of increase in basicity and the production cost can be lowered.

At this time, the volatile substance may be tar.

The volatile material is preferably contained in an amount of 15 to 25% of the total weight of the carbonaceous material. This is intended to allow the volatile material to have a proper viscosity so as to be able to produce briquettes without a binder, while at the same time acting as a reducing agent.

 If the content of the volatile substance is less than 15% of the total weight of the carbonaceous material, there may arise a problem that the carbonaceous material and the iron ore are not properly mixed and bonded. When the content of the volatile substance exceeds 25% The amount of carbon contained in the carbonaceous material is reduced, so that the degree of reduction of the partially reduced iron to be produced may be lowered, and the strength of the partially reduced iron may be lowered after the reduction.

The carbonaceous built-in briquettes containing the carbonaceous material including the volatile material of the present invention can be manufactured by mixing and press-molding a mixture containing iron ore and 10 to 20% carbonaceous material by weight of the iron ore.

For example, it can be produced by uniformly mixing iron ore and carbonaceous material, filling it in a mold, and then press-molding it by press molding.

At this time, it is preferable that the iron ores and the carbon materials have a fine powder form, and the iron ores and the carbon materials have a particle size of 75 to 150 μm.

This is to widen the contact area between the iron ore and the carbonaceous material so as to be more easily reduced. That is, when the iron ore is reduced by the carbonaceous material contained in the carbonaceous material-containing briquette, the reduction of the contact area can be facilitated. Therefore, the iron ore and the carbonaceous material preferably have a fine powder form, and more preferably have a particle size of 75 to 150 μm.

The manufacturing method for manufacturing the carbon-bearing briquettes of the present invention has an advantage of not including a binder.

Conventionally, in the manufacturing method for manufacturing the carbon-bearing briquettes, a binder is essentially used to increase the viscosity and adhesion of the iron ore and the carbonaceous material mixture. However, as the amount of the binder increases, the final composition of the molten steel may change during the manufacture of the briquettes, resulting in a problem that the final strength of the steel can not be achieved. In addition, as the amount of the binder increases, Which may lead to inefficient operation of the blast furnace and increase the production cost.

On the other hand, the manufacturing method for manufacturing the carbon-bearing briquettes of the present invention can improve the tackiness when mixing the carbon material and the iron-based carbonaceous material by using the carbonaceous material containing the volatile substance having viscosity, There are advantages to be solved.

In addition,

Manufacturing the carbonaceous built-in briquettes (step 1); And

(Step 2) of reducing the carbonaceous built-in briquettes in the reduction furnace,

Wherein the reduction is performed in a gas atmosphere containing 10 to 20% O ₂ and CO ₂ gases, respectively.

The reducing method of the present invention is for reducing the briquette embedded in a carbonaceous material in an oxidizing atmosphere. The briquetting of the carbonaceous material can be reduced by adjusting the reducing temperature and the reducing time, thereby reducing the reoxidization. have.

In addition, the method for reducing the briquetting of the present invention can reduce the briquetting of the carbonaceous material in the atmosphere where the oxygen and the carbon dioxide are supplied, There is an advantage that it can be reduced.

Hereinafter, the reducing method of the carbon-bearing briquettes of the present invention will be described in detail for each step.

In the reducing method of the carbon-bearing briquettes of the present invention, step 1 is a step of producing the carbon-bearing briquettes.

The step 1 is a step of producing the carbonaceous material-containing briquettes of the present invention. The carbonaceous material-containing briquettes may be manufactured by press molding a mixture containing iron ore and 10 to 20% carbonaceous material, The iron ores and the carbonaceous material may be uniformly mixed, filled in a mold, and then press-formed by press molding.

At this time, the iron ore and the carbonaceous material are preferably in a non-powder form and more preferably have a particle size of 75 to 150 μm. This is intended to facilitate the reduction of iron ore and carbonaceous materials by widening the contact area. That is, when the iron ore is reduced by the carbonaceous material contained in the carbonaceous material-containing briquettes, the greater the contact area, the easier the reduction. Accordingly, the iron ore and the carbonaceous material preferably have a fine powder form, and more preferably have a particle size of 75 to 150 μm.

In addition, the carbonaceous material includes a volatile substance, and thus it is possible to manufacture a carbonaceous material-containing briquette without using a binder.

At this time, it is preferable that the volatile material is contained at 15 to 25% of the total weight of the carbonaceous material. This is intended to allow the volatile material to have a proper viscosity so as to be able to produce briquettes without a binder, while at the same time acting as a reducing agent.

 If the content of the volatile substance is less than 15% of the total weight of the carbonaceous material, there may arise a problem that the carbonaceous material and the iron ore are not properly mixed and bonded. When the content of the volatile substance exceeds 25% The amount of carbon contained in the carbonaceous material is reduced, so that the degree of reduction of the partially reduced iron to be produced may be lowered, and the strength of the partially reduced iron may be lowered after the reduction.

In the reducing method of the carbon-bearing briquettes of the present invention, the step 2 is a step of reducing the carbon-bearing briquettes in the reducing furnace.

Step 2 is a step for partially reducing the carbon-containing briquettes of the present invention in an oxidizing atmosphere.

As the reducing furnace for the reduction, supercanal furnaces of FIG. 1 may be used, but the present invention is not limited thereto.

As shown in FIG. 1, the reducing furnace 100 includes:

Alumina reaction tube 101;

An SUS mask 102 positioned above the reaction tube 101 to seal the reaction tube 101;

A platinum (Pt) wire basket 103 supporting the specimen 108 and transferring heat to the specimen 108;

A gas injection unit 104 connected to the STS mask 102 for injecting gas into the reaction tube 101; And

And a gas discharging unit 105 connected to the STS mask 102 for discharging gas from the reaction tube.

At this time, the reduction is preferably performed in a gas atmosphere containing 10 to 20% O ₂ and CO ₂ gas, respectively.

This is to form an appropriate oxidizing atmosphere in which a reduction reaction can take place. If the O ₂ and CO ₂ gases are contained in an amount exceeding 20%, there may arise a problem that the reduction reaction of iron ores does not proceed.

The gas atmosphere may be formed using the reducing furnace of Fig.

That is, the carbonaceous built-in briquettes manufactured in the step 1 are charged into the upper part of the platinum (Pt) wire basket 103 of the reduction furnace 100 and then introduced into the gas injection part 104 through a mass flow controller (MFC) And can be formed by injecting O ₂ and CO ₂ gas.

The reduction in step 2 is preferably performed at a temperature of 1000 to 1200 ° C.

This is to reduce the iron ore contained in the carbonaceous material-containing briquettes, and the carbonaceous material-containing briquettes may be reduced to a reduction ratio of 20 to 45% at the temperature.

The temperature may be formed by the heat transmitted through the platinum (Pt) wire basket 103 after the gas atmosphere is formed in the reaction tube 101 in the reducing furnace 100 of FIG.

If the temperature is less than 1000 ° C., the iron ores may not be reduced. If the temperature exceeds 1200 ° C., the problem of difficulty in progressing the partial reduction iron process due to melting of the iron ores Lt; / RTI >

At this time, the reduction time at the temperature is preferably 40 minutes or less.

If the reduction time at the temperature exceeds 40 minutes, although the oxidation and reduction are no longer carried out, the problem that the energy is used more than necessary may occur as the heat source continues to be used.

It is more preferable that the reduction time at this temperature is 20 minutes or less.

This is to prevent the strength from being lowered by the re-oxidation of the briquettes.

If the reduction time at the temperature exceeds 20 minutes, a crack may be generated in the briquettes due to the reoxidation and pore formation of the briquet, and the strength may be reduced, There is a possibility that the strength of the partially reduced iron produced by the reduction method is low.

Further, the reduction time at the temperature is more preferably 2 minutes to 14 minutes.

This is so that the reduction rate of the briquettes is more than 30%.

When the partially reduced iron having a reduction ratio of 30% or more is used in the blast furnace, there is an advantage that the amount of generated carbon dioxide in the whole process can be reduced.

When the reduction time at the temperature is out of 2 to 14 minutes, the reduction rate is less than 40%.

It is more preferable that the reduction time at this temperature is 4 minutes to 8 minutes.

This is so that the reduction rate of the briquettes is more than 40%.

When the partially reduced iron having a reduction ratio of 40% or more is used in the blast furnace, the amount of generated carbon dioxide in the entire process can be further reduced.

When the reduction time at this temperature is out of the range of 4 minutes to 8 minutes, the reduction rate is less than 40%.

Further,

A partially reduced iron produced by the above method is provided.

In the partially reduced iron of the present invention, 20 to 45% of the carbonaceous internal briquettes of the present invention are reduced. When used in a blast furnace, the reduction ratio of the blast furnace in the blast furnace is remarkably reduced, productivity is improved and air permeability in the blast furnace is improved. There is an advantage to contribute.

Hereinafter, the present invention will be described in detail with reference to Examples and Experimental Examples.

However, the following Examples and Experimental Examples are merely illustrative of the present invention, and the contents of the present invention are not limited by the following Examples.

≪ Example 1 >

Step 1: A hematite containing 20% by weight of hematite containing the components as shown in Table 2 below was prepared in hematite containing the components shown in Table 1 below. Then, after then pulverized by ball milling the mixture was screened and the mixture having a particle size of 75 to 150 μm, and filled with the selected mixture in briquettes molded by using a press pressure forming in the 8 ton / cm ³ Pressure Diameter 10 mm, and an inorganic 2 g cylindrical briquettes.

T.Fe SiO ₂ Al ₂ O ₃ MgO CaO 66.96 2.53 0.6 0.15 0.03

Carbon (wt%) Volatile material (tar) (% by weight) Ash (% by weight) Water (% by weight) 65.7 22.9 10.1 1.3

Step 2: The briquettes were charged into a supercanal furnace, and then a mixed gas containing 10% of oxygen and 80% of nitrogen gas, respectively, was injected constantly. Thereafter, the carbonaceous material-containing briquettes were reduced by heat treatment at a heating rate of 50 ° C / min from 200 to 1000 ° C.

≪ Example 2 >

Carbonaceous embedded briquettes were reduced in the same manner as in Example 1, except that in the reduction of step 2 in Example 1, the final temperature was changed to 1100 ° C.

≪ Example 3 >

The burying of the carbonaceous briquettes was carried out in the same manner as in Example 1, except that in the reduction of step 2 in Example 1, the final temperature was changed to 1200 ° C.

<Example 4>

Carbonaceous internal briquettes were reduced in the same manner as in Example 1, except that in the reduction of step 2 in Example 1, the final temperature was changed to 1200 ° C and the temperature was maintained for 2 minutes.

&Lt; Example 5 >

Carbonaceous embedded briquettes were reduced in the same manner as in Example 1, except that in the reduction of step 2 in Example 1, the final temperature was changed to 1200 캜 and maintained for 4 minutes after arrival.

&Lt; Example 6 >

Carbonaceous internal briquettes were reduced in the same manner as in Example 1, except that in the reduction of step 2 in Example 1, the final temperature was changed to 1200 ° C and the temperature was maintained for 6 minutes.

&Lt; Example 7 >

Carbonaceous embedded briquettes were reduced in the same manner as in Example 1, except that in the reduction of step 2 in Example 1, the final temperature was changed to 1200 ° C and the remaining temperature was maintained for 8 minutes.

&Lt; Example 8 >

Carbonaceous embedded briquettes were reduced in the same manner as in Example 1, except that in the reduction of step 2 in Example 1, the final temperature was set to 1200 ° C and the temperature was maintained for 10 minutes.

&Lt; Example 9 >

Carbonaceous embedded briquettes were reduced in the same manner as in Example 1, except that in the reduction of step 2 in Example 1, the final temperature was changed to 1200 캜 and maintained for 20 minutes after arrival.

&Lt; Example 10 >

Carbonaceous internal briquettes were reduced in the same manner as in Example 1, except that in the reduction of step 2 in Example 1, the final temperature was changed to 1200 ° C and the temperature was maintained for 30 minutes.

&Lt; Example 11 >

Carbonaceous internal briquettes were reduced in the same manner as in Example 1, except that in the reduction of step 2 in Example 1, the final temperature was set to 1200 ° C and the temperature was maintained for 40 minutes.

&Lt; Comparative Example 1 &

Carbonaceous embedded briquettes were reduced in the same manner as in Example 1, except that in the reduction of step 2 in Example 1, the final temperature was changed to 800 ° C.

&Lt; Comparative Example 2 &

Carbonaceous embedded briquettes were reduced in the same manner as in Example 1, except that in the reduction of step 2 in Example 1, the final temperature was changed to 900 ° C.

<Experimental Example 1> Shape and Strength of Partially Reduced Iron according to Reduction Temperature

In order to confirm the reduction characteristics and strength changes of the carbonaceous internal briquettes according to the present invention, the following experiment was conducted.

The briquettes reduced by Comparative Examples 1 and 2, Examples 1 to 3 and Examples 8 to 11 were taken and the shape was observed with the naked eye. The results are shown in Fig. 2. The results are shown in Fig. 4 Respectively. Further, the results of observing the changes during holding at 1200 DEG C with a scanning electron microscope (SEM) are shown in Fig.

As shown in Fig. 2, no specific change was observed in the case of the briquettes subjected to the comparative examples 1 and 2 as a result of observation of the surface and the cross section of the briquet, while in the case of the briquettes of Examples 1 to 3 and 8 to 11, Can be seen. As a result, it can be expected that the reduction reaction of the carbonaceous internal briquetting hardly occurs at a temperature lower than 1000 ° C.

In the case of the briquettes of Examples 8 to 11 in which the heat treatment was performed at 1200 占 폚 for 10 minutes, 20 minutes, 30 minutes and 40 minutes, as shown in Fig. 3, the generation of pores by gasification in the carbonaceous material Formation of an oxide layer inside the briquet can be confirmed. That is, in the case of the briquettes of Examples 8 and 9, relatively few pores were formed, whereas in the case of the briquettes of Examples 10 and 11, the reoxidation layer and pore growth cracked as the heat treatment time was increased can confirm.

As shown in FIG. 4, the strength after the reduction reaction according to the heat treatment temperature for reduction was measured. As a result, the briquettes (Comparative Examples 1 and 2 and the briquettes of Example 1) Comparing the compressive strengths of the briquettes subjected to the heat treatment at the temperature of 1000 to 1200 DEG C (the briquettes of Examples 1 to 9), the strength of the briquettes decreased as the temperature increased. It can be seen that as the temperature increases and the holding time increases, the compressive strength increases. Comparing Examples 9 to 11, it is confirmed that as the holding time at 1200 캜 increases, the compressive strength decreases again.

That is, the compressive strength increased as the temperature increased between 1000 and 1200 ° C, and the maximum value of about 335 kg / cm ² was exhibited in the briquettes of Example 9 in which the heat treatment was performed at 1200 ° C for 20 minutes. .

 3 and 4, when the heat treatment is performed at 1200 ° C. for more than 20 minutes, cracks are generated in the briquettes and the decrease in the strength is observed, As the briquette reoxidation progresses, cracks occur due to the separation of the external reoxidation layer and the internal reduction layer of the briquettes, resulting in a decrease in the strength of the briquettes.

As a result, it can be seen that the strength of the carbon-bearing briquette of the present invention drastically decreases when heat treatment is performed at 1200 ° C. for more than 20 minutes.

<Experimental Example 2> Analysis of change in exhaust gas (CO, CO ₂ , O ₂ )

In order to confirm the change of the exhaust gas according to the temperature of the carbon-bearing briquettes of the present invention, the following experiment was conducted.

(Germany, MRU company, DELTA 1600S model) in which the temperature was raised to 50 占 폚 per minute between 200 and 1200 占 폚 in order to confirm the gas change caused by the reduction method of the present invention, The concentrations of CO, CO ₂ and O ₂ were analyzed at intervals of 20 seconds, and the results are shown in FIG.

As shown in FIG. 5, it can be seen that no CO was generated regardless of the reduction reaction temperature interval. This can be seen to be due to hayeotgi generate CO ₂ and the carbonaceous material and CO generated during the direct reduction of the iron ore react with the gas atmosphere of O ₂ present inside the briquettes.

That is, when reducing the carbonaceous internal briquettes in the conventional inert atmosphere, CO is generated by reduction of the briquettes, while the reduction method of the present invention has the advantage of reducing the carbonaceous internal briquettes and not producing CO gas .

In addition, it can be confirmed that the concentration of carbon dioxide and the concentration of oxygen have opposite tendencies. That is, the carbon dioxide concentration increased as the temperature increased from 800 to 1200 ° C., and the maximum value was maintained when the temperature was maintained at 1200 ° C. for about 2 minutes. After that, the carbon dioxide concentration decreased and then the holding time at 1200 ° C. exceeded about 40 minutes While maintaining the same initial gas composition as the initial gas, while the oxygen concentration shows a tendency to be opposite to the change in the carbon dioxide concentration.

In the reduction method of the present invention, the generation of carbon dioxide can be seen to occur when CO generated in the direct reduction reaction of the carbonaceous material and iron ore existing in the briquettes is generated by reacting with the atmospheric gas O _2. Therefore, The reduction in oxygen concentration can be seen as a result of the reduction of the carbonaceous briquettes.

Therefore, it can be seen from the above results that the reduction of the carbonaceous internal briquettes of the present invention has been completed after about 2 minutes at 1200 ° C. and then about 40 minutes.

&Lt; Experimental Example 3 > The unreacted carbon and oxygen content of the carbon-bearing briquettes of the present invention

In order to confirm the amount of unreacted carbon and oxygen in the carbon-bearing briquettes of the present invention, the following experiment was conducted.

The amount of unreacted carbon and oxygen in the carbonaceous internal briquettes can be calculated using the following equations (1) and (2) using the change in flow rate of CO and CO ₂ in the exhaust gas measured in Experimental Example 2 And the results are shown in Fig.

<Formula 1>

(Q _total ) _t : total gas flow at time t

Q _co : CO gas flow at time t

Q _co2 : CO ₂ gas flow rate at time t

(% CO) _t : CO volume at time t%

(% CO ₂ ) _t : CO ₂ volume at time t%

<Formula 2>

(% O) _t : concentration of unreacted oxygen at time t

(% C) _t : concentration of unreacted carbon at time t

(W _O ) _t : the weight of oxygen remaining in the briquettes at time t

(W _C ) _t : Weight of remaining carbon in the briquettes at time t

(W _B ) _t : Weight of briquet at time t

At this time, the amount of carbon in the briquettes before the reaction included not only the fixed carbon but also the amount of carbon contained in the volatiles through the component analysis, and only the amount of oxygen present in the iron ore was calculated.

As shown in FIG. 6, the amount of unreacted carbon present in the briquettes sharply decreases at the initial stage of the reaction and gradually decreases with the elapse of the reaction time. And a certain amount of about 2% by weight is maintained after 20 minutes.

In addition, the amount of unreacted oxygen existing in the briquettes tends to decrease sharply at the initial stage of the reaction as in the case of unreacted carbon. However, it can be confirmed that the residual amount tends to increase after a lapse of the reaction time of 26 minutes, that is, after about 6 minutes after reaching 1200 ° C. It can be seen that the amount of oxygen existing in the brittle is increased due to the reoxidation phenomenon caused by oxygen in the injected gas. It can be confirmed that the reaction time is maintained at a constant level after 40 minutes of reaction time, i.e., about 20 minutes after reaching 1200 占 폚. This can be attributed to the increase in diffusion resistance of oxygen due to the reoxidation layer formed on some reduced Fe surfaces.

From the above results, it can be seen that the reduction reaction is dominant up to about 6 minutes after reaching 1200 ° C, and then the reoxidation phenomenon by the injected oxygen occurs.

Further, it can be seen that the reduction reaction is almost completed at about 20 minutes after reaching 1200 ° C.

EXPERIMENTAL EXAMPLE 4 The reduction ratio of the carbon-bearing briquettes of the present invention

In order to confirm the degree of reduction and metallization of the carbon-bearing briquettes of the present invention, the following experiment was conducted.

Based on the calculation results of the concentration of unreacted carbon and oxygen in the carbonaceous internal briquettes according to the reduction reaction time of Experimental Example 3, the reduction ratio was calculated using the following Formula 3, and the results are shown in FIG.

<Formula 3>

(W _O ) _O : Oxygen mass in the briquettes

(W _B ) _O : Initial briquette mass

As shown in FIG. 7, the reduction rate tends to be 1% or less until about 8 minutes after the initiation of the reaction, and rapidly increases from the point at which the temperature reaches 1000 ° C for 16 minutes, and the reaction time is 22 minutes to 34 minutes, And a reduction rate of about 40% or more between 24 minutes and 28 minutes, that is, between 4 minutes and 8 minutes after reaching 1200 ° C, and a reaction time of 26 minutes, that is, And a maximum reduction rate of about 41% at about 6 minutes after reaching 1200 ° C.

Thereafter, the reduction rate tends to decrease due to the reoxidation by the injected oxygen. After 20 minutes after reaching 1200 ° C, the reduction reaction and the reoxidization are terminated, and the reduction rate is about 22%.

As a result, it can be seen that the reduction of the carbonaceous internal briquettes in the atmosphere in which oxygen and carbon dioxide are provided is performed at 1000 to 1200 ° C, and in particular, a reduction rate of about 30% or more is attained between 2 minutes and 14 minutes after reaching 1200 ° C , And it can be seen that the reduction rate is about 40% or more between 4 minutes and 8 minutes after reaching 1200 ° C.

In addition, it can be seen that the reduction rate is reduced by the reoxidization process up to 20 minutes after reaching 1200 ° C., and after 20 minutes, the reoxidation and reduction reaction are completed, and the partially reduced iron having 22% Can be produced.

EXPERIMENTAL EXAMPLE 4 The metallization ratio of the carbon-containing briquettes of the present invention

In order to confirm the metallization ratio of the carbonaceous internal briquettes according to the reduction method of the carbonaceous built-in briquettes of the present invention, the following experiment was conducted.

The briquettes reduced by Comparative Examples 1 and 2, Examples 1 to 3 and Examples 8 to 11 were subjected to KS E 3016 metal iron quantitative analysis to calculate metallization ratios. The results are shown in FIG.

As shown in Fig. 8, the metallization ratios of the carbonaceous material-containing briquettes were compared with those of the briquettes of Comparative Examples 1 and 2 and Example 1. As a result, it was found that the metallization rate was 0% at 1000 to 1200 ° C And the metalization rate of the briquettes of Examples 1 to 3 was found to increase sharply at 1000 to 1200 ° C.

In the case of the briquettes subjected to the heat treatment at 1200 캜 for 10 minutes, the briquettes of Comparative Examples 1 and 2, Examples 1 to 3, and Examples 8 to 11 were subjected to a maximum metallization rate of about 31% And in the case of the briquettes of Examples 9 to 11 which were heat-treated at 1200 DEG C for 10 minutes or more, the metallization rate was decreased.

From the above results, it can be seen that the decrease of metallization rate is due to the phenomenon of reoxidation by injected oxygen.

From the above results, it can be seen that the reduction method of the present invention progresses the reduction of briquettes at a temperature of 1000 ° C or higher. Referring to Experimental Example 3, It is anticipated that the rate will rise.

100: reduction furnace
101: alumina reaction tube
102: STS mask
103: Platinum (Pt) wire basket
104: gas injection part
105: gas discharge portion
106: alumina tube
107: tube furnace
108: The Psalms
109: Heat source
110: alumina ball

Claims (9)

Iron ore and 10 to 20% of the weight of the iron ore, wherein the carbonaceous material comprises volatiles.
The method according to claim 1,
The carbonaceous material
Wherein the volatile matter is contained in an amount of 15 to 25%.
The method according to claim 1,
The carbonaceous built-
Wherein the briquette comprises no binder.
A process for producing a carbon-containing briquet of claim 1 (step 1); And
(Step 2) of reducing the carbonaceous built-in briquettes in the reduction furnace,
Wherein the reduction is performed in a gas atmosphere containing 10 to 20% O ₂ and CO ₂ gases, respectively.
5. The method of claim 4,
Wherein the reduction of step 2 is performed at a temperature of 1000 to 1200 ° C.
6. The method of claim 5,
The reduction time at this temperature is
Lt; RTI ID = 0.0 &gt; 2 &lt; / RTI &gt; to 14 minutes.
6. The method of claim 5,
The reduction time at this temperature is
Lt; RTI ID = 0.0 &gt; 4 &lt; / RTI &gt; to 6 minutes.
A partially reduced iron produced by the reducing method of claim 4.
9. The method of claim 8,
Wherein the partially reduced iron has a reduction ratio of 30 to 40%.

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