KR101712829B1 - Burning furnace and method of manufacturing partially-reduced iron using the same - Google Patents

Abstract

The calcining furnace according to the present invention comprises: a reducing part for reducing at least a part of the iron raw material by heat treating a plurality of compacted light including a carbonaceous material and an iron raw material at a first temperature; And a smoothing unit connected to a downstream end of the reducing unit and configured to heat-treat the plurality of compacted light beams at a second temperature lower than the first temperature. The partial reduced iron is manufactured using the sintering furnace, And the metallization ratio can be improved at the same time.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burning furnace and a method for manufacturing the same,

The present invention relates to a firing furnace and a method for manufacturing partially reduced iron using the firing furnace, and more particularly, to a firing furnace capable of simultaneously reducing compressive strength and metallization after reducing compacted light including carbonaceous and iron materials, To a reduced iron production method.

A typical reduced iron manufacturing apparatus includes a plurality of hoppers for receiving iron raw materials and carbonaceous materials, a crusher for receiving and crushing iron raw materials and carbonaceous materials, a mixer for mixing and supplying iron raw materials and carbonaceous materials, And a baking furnace for baking and baking the briquettes produced in the briquetting machine.

Currently, 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 into a blast furnace and blowing hot air to reduce iron ore to iron.

Since the blast furnace process, which is a type of molten iron production facility, requires a raw material having a strength that is above a certain level and a particle size capable of ensuring ventilation in the furnace, the carbon source used for the fuel and the reducing agent It relies on coke treated with a specific coking coal, and it mainly relies on sintered ores that have undergone a series of agglomeration processes.

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 raw gas per unit volume of the sintered ore in the lump state is extremely small as compared with the case of 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.

There has been developed a process for manufacturing reduced iron directly by reducing iron in a rotary hearth furnace (RHF) by briquetting or pelletizing the iron ore minerals. However, in the case of direct reduced iron production, the output is in the range of 150,000 to 500,000 tons per year, and there is a limit to mass production and the reduction rate is over 95%, which is used as raw material for electric furnace.

In addition, a process for producing partially reduced iron by compacting minerals into briquettes or pellets and firing at a maximum temperature of 1,350 ° C. has been developed, and mass production of up to 4 million tons is possible. However, such a process has a problem in that the temperature and the like in the calcining furnace can not be appropriately controlled because the process is carried out in an unsealed open burning furnace, and the compressive strength and metallization ratio of the partially reduced casting are low.

KR 10-2013-0053089 A

The present invention provides a sintering furnace capable of simultaneously improving the room temperature compressive strength and metallization ratio of partially reduced iron by controlling temperature, oxygen concentration and holding time, and a method for manufacturing partially reduced iron using the sintering furnace.

The present invention provides a firing furnace and a method for manufacturing partially reduced iron using the firing furnace, which can reduce the quality deviation caused by the height of the bundle of coarse light stacked on the bogie.

The calcining furnace according to an embodiment of the present invention includes a reducing part for reducing at least a portion of the iron raw material by heat treating a plurality of compacted light including a carbon material and an iron raw material at a first temperature; And a smoothing unit connected to a downstream end of the reducing unit and heat-treating the reduced plurality of intense light at a second temperature lower than the first temperature.

A drying unit connected to a front end of the reducing unit to dry the plurality of compacted lights, and a volatile fraction removing unit to remove volatile components contained in the plurality of compacted lights; And a cooling unit connected to a rear end of the smoothing unit and cooling the plurality of large-sized lights heat-treated.

And an atmosphere control unit connected to the reducing unit and the smoothing unit and supplying an atmospheric gas containing air to the reducing unit and the smoothing unit to control the oxygen concentration in the reducing unit and the smoothing unit.

The oxygen concentration in the homogenizing unit is maintained to be lower than the oxygen concentration in the reducing unit while the plurality of intense light beams are being heat-treated, and the oxygen concentration in the homogenizing unit is not more than 5% Can be maintained.

The second temperature may be selected in the range of 1000 ° C to 1200 ° C.

The plurality of compacted light beams may further include a heat source stacked on a carriage moving along a movement path connecting the reducing unit and the uniformizing unit to a predetermined height and provided on one side of the movement path.

According to another aspect of the present invention, there is provided a partially reduced iron manufacturing method comprising the steps of: heat treating a plurality of compacted light including a carbonaceous material and an iron raw material at a first temperature to reduce at least a part of the iron raw material; And uniformizing the plurality of compacted light beams for heat-treating the reduced plurality of compacted light at a second temperature lower than the first temperature.

Further comprising a step of drying the plurality of compacted light beams before the reducing step and a step of removing volatile components included in the plurality of compacted light beams, wherein the plurality of compacted light beams after heat- Step < / RTI >

The oxygen concentration in the homogenizing step may be maintained to be lower than the oxygen concentration in the reducing step, and the oxygen concentration may be an atmosphere containing at least one selected from oxygen, air, inert gas, Gas, and the oxygen concentration in the homogenizing step can be maintained at 5% or less.

The second temperature may be selected in the range of 1000 ° C to 1200 ° C.

Further comprising the step of stacking the plurality of intense light beams on the carriage so as to have a predetermined height, wherein heat can be supplied in one direction of the carriage moving along the movement path during the reducing and leveling steps.

The partially reduced iron according to another embodiment of the present invention may be manufactured by the above partially reduced iron manufacturing method and have a room temperature compressive strength of 150 kgf / p or more and a metallization ratio of 45% or more.

According to the embodiments of the present invention, a plurality of compacted light including a carbonaceous material and an iron material is moved in a moving type bulk burning furnace and heat-treated and reduced at a first temperature, and then subjected to heat treatment at a second temperature lower than the first temperature, Temperature compressive strength and the metallization ratio of the partially reduced iron produced by homogenizing a plurality of compacted light beams can be improved at the same time. In addition, it is possible to reduce deviation of the room temperature compressive strength and the metallization ratio caused by the heights of the plurality of compacted light stacks stacked on the truck, so that the partially reduced iron of uniform quality can be stably manufactured.

Accordingly, in producing the molten iron by the blast furnace method using the reduced iron according to the present invention, it is possible not only to have sufficient strength, but also to reduce the production cost by saving the energy required for reduction in the blast furnace.

1 is a block diagram showing a configuration of a partially reduced iron manufacturing facility according to an embodiment of the present invention.
2 is a schematic view showing a structure of a calcining furnace according to an embodiment of the present invention.
3 is a graph showing changes in compressive strength at room temperature with reduction time.
4 is a graph showing the change in the metallization ratio with the reduction time.
5 is a graph showing the change in the compressive strength at room temperature according to the homogenization time in the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of other various forms of implementation, and that these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know completely.

FIG. 1 is a block diagram showing the construction of a partially reduced iron manufacturing facility according to an embodiment of the present invention, and FIG. 2 is a schematic view showing a structure of a firing furnace according to an embodiment of the present invention.

First, a method of manufacturing the partially reduced iron will be briefly described as follows.

Partially reduced iron is produced by preparing a partially reduced iron by preparing and mixing a carbonaceous material and an iron raw material, forming a mixture of the iron raw material and the carbonaceous material to produce a plurality of compacted light, and then burning and reducing the compacted light in the burning furnace. Here, the iron raw material may be at least one of iron ore as a reducing agent, iron oxide dust generated during a steelmaking process, and sludge. The carbonaceous material is a reducing material for reducing the iron raw material, and at least one of the coal dust and the carbon dust generated in the steelmaking process can be used. Here, the partially reduced iron means that the whole of iron (Fe) contained in the iron raw material, that is, 100% is not reduced but partially reduced to less than 100%. Of course, reduced iron reduced to 100% can be produced by controlling the firing time or the heat treatment temperature, but there is a problem that a burden is imposed on the firing apparatus in order to produce reduced iron having 100% reduction.

As shown in FIG. 1, the apparatus for producing partially reduced iron according to the present invention comprises a plurality of hoppers 100 and 200 in which iron raw materials and carbonaceous materials are contained, iron feedstocks and raw materials from hoppers 100 and 200, A mixer 300 for supplying the crushed iron raw material and the carbonaceous material and mixing the iron raw material and the coal at a predetermined ratio, and a mixer 300 for compressing the mixed mixture to form a briquette And a firing furnace 500 for heat-treating a plurality of compacted light beams formed in the optical molding machine 400 and the compact optical molding machine 400, and firing and reducing the fired light. Although the iron source and the carbonaceous material are presented as raw materials for the briquette, auxiliary materials such as a binder for facilitating the bonding between the iron source and the carbonaceous material and for improving the strength of the briquette can be additionally used. Such a subsidiary material may be added to an additional hopper Lt; / RTI >

In the mixer 300, the ultrafiltrate raw material having a particle size of 0.1 mm or less and the carbonaceous material are mixed at a ratio of 8: 2, for example, and the compact optical molding machine 400 is installed in a manner A pair of rollers, or a twin roll type molding machine. Thus, when the mixture is charged between the pair of rolls, extruding due to the rotation of the pair of rolls produces intense light in the form of briquettes.

The baking furnace 500 is a furnace for heating and reducing a plurality of compacted light beams produced in the compacting optical molding machine 400 and cooling the compacted compacts. For example, the furnace 500 has an inner space, which is a movement path through which a bogie accommodating large- And a heat source (heating means) is provided, which heat-treats and reduces a plurality of intense light beams.

Referring to FIG. 2, the firing furnace 500 according to the present invention includes a carbonaceous material that forms a movement path for heating a bogie having a plurality of intense light therein while moving from one side to the other, and a plurality of compacted A reducing part 530 for reducing at least a part of the iron raw material by heat treatment at a first temperature; And a smoothing unit 540 connected to a rear end of the reducing unit 530 and for heat-treating the reduced plurality of intense light at a second temperature lower than the first temperature. The drying unit 510 is connected to the front end of the reducing unit 530 to dry a plurality of intense light, and a volatile fraction removing unit 520 for removing volatile components included in the plurality of intense lights. And a cooling unit 550 connected to the rear end of the smoothing unit 540 to cool a plurality of heat-treated compacted light.

The drying unit 510, the volatile fraction removing unit 520, the reducing unit 530, the smoothing unit 540 and the cooling unit 550 constituting the baking furnace 500 have an internal space (not shown) So that bogies accommodating a plurality of intense light beams can be moved along the movement path. The bogie moves along the movement path of the endless track formed in a shape similar to the sintering furnace 500 and continuously moves a plurality of intense light beams. The firing furnace 500 moves the upper side movement path of the endless track shape As shown in Fig.

The drying unit 510 removes water contained in the plurality of intense light to increase the efficiency of the reaction. That is, when moisture is contained in the compacted light produced by the compacting optical molding machine (400), if it is suddenly heated to a high temperature close to the reduction temperature, the moisture inside the compacted light is evaporated and the compacted light is destroyed or the efficiency Can be inhibited. In order to prevent this, the drying unit 510 heats the carbonaceous intense light to a predetermined temperature, for example, about 200 to 300 ° C to remove moisture contained in the carbonaceous intrinsic light.

The volatile fraction removing unit 520 heats the plurality of roughly-lighted lights dried in the drying unit 510 to remove tar, volatile matter, and the like contained in the coal. At this time, tar, volatile matter, and the like contained in the coal in the carbonaceous built-in light are volatilized at a temperature of about 300 ° C to 700 ° C. Tar and volatile matter in the coal are changed to CHn series, which can be used as fuel at the time of combustion, so that the exhaust gas generated in the coal gasification process in which volatile components are removed can be supplied to the cooling unit 550 by an atmosphere control unit described later. When the flue gas generated in the coal gasification process is supplied to the cooling unit 550, the CHn-based flue gas comes into contact with the partially-reduced reduced iron at high temperature, and CHn is decomposed, and the cooling efficiency of the reduced iron can be improved by the heat of decomposition. Further, the C and H gases generated by the decomposition of the flue gas may be supplied to the reduction unit 530 and used as a fuel necessary for reducing the intense light.

Further, when the oxygen concentration in the volatile fraction removing unit 520 is high, coal and volatile matter in the intense light may be burned, so that the temperature of the briquetting coal may be rapidly increased to make it difficult to control the process temperature. Or less (for example, 10% or less).

The reducing unit 530 is a place where a reduction reaction of a plurality of compacted light in which volatile components are removed occurs. In the reduction unit 530, a reduction reaction occurs spontaneously by the coal in the intense light. In order to improve the efficiency of the reduction reaction and inhibit the formation of the melt in the intense light, the reduction temperature (i.e., the first temperature) . A closer look at the reduction reaction reveals that carbon (carbon) present in the coal of carbonaceous intrinsic light directly reacts with oxygen in Fe ₂ O ₃ , or carbon monoxide generated in the combustion process reacts with oxygen in Fe ₂ O ₃ , , The iron raw material of the coarse light is reduced to FeO to Fe.

When the oxygen concentration in the reducing unit 530 is too high, coal in the intense light is heavily used as a combustion gas, which lowers the metallization rate. Therefore, the oxygen concentration is controlled to be lower than a certain level (for example, 10% or lower) There is a need.

Referring to FIG. 3, which is a graph showing the change in the compressive strength at room temperature according to the reduction time, the compacted light (or the partially reduced iron) in which at least a part of the iron material in the intense light is reduced in the reducing unit 530, Temperature) is longer (i.e., the reduction time), the compressive strength at room temperature is increased. It is understood that the sintering reaction of the metal (Fe) and other oxides in the partially reduced iron proceeds and the compressive strength at room temperature is increased. Meanwhile, referring to FIG. 4, which is a graph showing the change in metallization rate according to the reduction time, it can be seen that as the reduction time becomes longer, the metallization rate of the partially reduced compacted light (partially reduced iron) decreases. This is due to the complete depletion of carbon in the intense light and the reoxidation of the reduced iron by the influence of external oxygen.

If the reduction time is maintained at a long time in the reducing unit 530 in which the carbon monoxide intensive light is reduced by itself, the strength of the partially reduced iron can be improved but the metallization rate is lowered by the reformation reaction. On the other hand, The metalization rate of the reduced iron can be secured to a high level, but the compressive strength at room temperature is lowered.

In order to withstand the pressure in the blast furnace when producing molten iron using the partially reduced iron, the partially reduced iron should have a compressive strength of at least 150 kgf / p at room temperature, and when the metallization rate of the partially reduced iron is low, It is difficult to expect a reduction ratio reduction effect, so that the metallization rate is required to be 40% or more. 3 to 4, the reduction time at which the optimum metallization rate (54%) is shown at a reduction temperature of 1200 ° C. is 15 minutes, but the compression strength at room temperature when the reduction time is 15 minutes is 120 kgf / p It exhibits a compressive strength that is too low for use in blast furnaces. On the other hand, if the reduction time is kept at about 25 minutes, the compressive strength is sufficient, but the metallization rate becomes too low again. Therefore, in order to produce an appropriate partially reduced iron for blast furnaces, the reducing conditions such as the reduction temperature and the reduction time, which are correlated with the characteristic change of the partially reduced iron, should be strictly controlled. However, It is very difficult to do.

On the other hand, generally, in the case of a burning furnace for producing partially reduced iron, a heat source is provided on one side (for example, the upper side) of the bogie moving path in the internal space. A plurality of burners are spaced apart from each other along the moving path of the bogie, The desired heat treatment temperature is achieved as the fuel provided to the burner of the burner is burned. For the production efficiency of partially reduced iron, the coarse light is loaded on the carriage more than a certain amount, and the loaded coarse light usually has a height of several hundred millimeters. The variation of temperature and oxygen concentration occurs in the upper and lower parts of the plurality of bundled light beams during the reduction reaction. For example, when hot air flows into the lower portion of the burner provided on the upper side of the conveyance path, the reaction proceeds first in the upper portion of the dense light pile, so that the carbonaceous material present in the intense light reacts with oxygen to cause combustion, As the heat generated moves downward, heat accumulation occurs, and the temperature fluctuates depending on the height of the massive light stack. Also, at the upper part of the dense light bundle, the amount of oxygen is burned while the coal inside the coarse light is burned and the amount of oxygen is decreased as it goes down to the lower part, so that the oxygen concentration varies according to the height of the dense light bundle. Since the strength and metallization ratio of the partially reduced iron vary depending on the reduction temperature and the oxygen concentration, there arises a problem that a deviation of the compressive strength and the metallization ratio also occurs in the upper and lower portions of the compacted pile.

It is difficult to simultaneously obtain the high compressive strength and the high metallization ratio of the partially reduced iron subjected to the reduction reaction in the reduction unit 530 and to solve the problem that the characteristic deviation occurs in the upper and lower portions of the compacted light stack. The uniforming unit 540 is connected to the rear end of the reducing unit 530 and the plurality of partially reduced compacted light in the reducing unit 530 is heat-treated at a temperature (second temperature) lower than the reducing temperature (first temperature).

5 is a graph showing the results of a comparison of the homogenization time (at a metallization rate of 54% and a room temperature compressive strength of 120 kgf / p) at a reduction temperature of 1200 deg. C for a reduction time of 15 minutes And Fig. It can be seen that the homogenization treatment increases the compressive strength at room temperature compared with the partially reduced iron without the homogenization step, and increases to 220kgf / p when the homogenization time is 20 minutes. On the other hand, the metallization ratio of the partially reduced iron can be maintained as high as 50% even after heat treatment of the intense light in the homogenizing part 540 for 20 minutes. This phenomenon occurs when the partially reduced compacted light in the reducing unit 530 is heat-treated at a temperature lower than the reducing temperature in the smoothing unit 540, thereby preventing further consumption of carbon in the compacted light and reoxidation of the reduced iron, The sintering reaction of the metal (Fe) and the other oxides is continued so as to improve the compressive strength at room temperature without lowering the metallization ratio.

Table 1 shows the compressive strength at room temperature when the homogenization temperature was changed. When the homogenization temperature was lower than 1000 ° C, sufficient heat energy was not supplied for the sintering reaction to continue, and the increase in the compressive strength at room temperature was not large. When the temperature is selected from 1000 ° C. to 1200 ° C., the sintering reaction of the metal (Fe) and other oxides in the partially reduced compacted light can proceed stably, thereby improving the compressive strength at room temperature. On the other hand, when the temperature rises excessively above 1200 ° C, a partial melting occurs in the intense light, which causes a phenomenon of sticking to the upper part of the truck, which not only pollutes the truck but also causes loss and recovery of the partially reduced iron . On the other hand, except for the temperature of 1200 占 폚 or more, the metallization rate did not change significantly from 50% to 54% depending on the homogenization temperature. Therefore, the homogenization temperature can be selected in the range of 1000 deg. C to 1200 deg.

Equalization
Temperature 900 950 1000 1100 1200 1250 Room temperature
Compressive strength 140 160 220 270 340 -

That is, according to the embodiment of the present invention, in the reducing unit 530, a reduction reaction occurs only at a reduction time (for example, a reduction time of 15 minutes) in which the metallization rate of the partially reduced iron is not reduced, (The ending point of the reduction process in the reducing unit may be set based on confirming that the metallization rate is maximized), and the partially reduced intense light in the reducing unit 530 is reduced in the smoothing unit 540 The sintering reaction of the metal (Fe) and the other oxides in the partially reduced reduced light is continued while suppressing the consumption of carbon in the intense light and the reoxidation of the reduced iron by the heat treatment at a temperature lower than the temperature, So as to improve the strength.

In addition, according to the variation of the temperature and the oxygen concentration according to the height of the bundle of light bundles stacked on the bogie, the bundle of light located at the top of the bundle is subjected to a reduction reaction at a relatively low temperature and a high oxygen concentration, When the heat treatment is performed at the second temperature in the smoothing unit 540, the sintering reaction proceeds while suppressing the reutilization of the reduced iron and the consumption of the carbon inside, The strength and the metallization ratio are improved, and the characteristic deviation according to the height of the compacted light stack can be solved.

Meanwhile, the homogenization temperature of the homogenizing unit 540 and the homogenization time may affect the room temperature compressive strength and the metallization ratio of the partially reduced iron, and the homogenization time may be 20 minutes or less. The reduced iron may be reoxidized by the oxygen remaining in the inner space of the smoothing unit 540.

The oxygen concentration in the homogenizing unit 540 may be maintained to be lower than the internal oxygen concentration of the reducing unit 530 during the homogenization heat treatment process so as to suppress the reoxidation of the reduced iron during the homogenization process. Further, the oxygen concentration can be kept low to prevent difficulty in controlling the homogenization temperature by the additional combustion of coal (carbon) remaining in the intense light. The oxygen concentration of the smoothing unit 540 may be maintained at 0% (inert atmosphere) to 5%. In the case of the reducing unit 530, oxygen is required to some extent for burning some coal present in the intense light in order to secure thermal energy required for the reduction reaction. However, after the reducing reaction is completed, the heat treatment in the uniforming unit 540 It is necessary that the oxygen concentration causing reoxidation is kept lower than the oxygen concentration in the reducing section 530. [ When the oxygen concentration in the uniform lower portion 540 is maintained at 5% or more, the reduced iron is reoxidized and the metallization rate is reduced.

5, the inside of the smoothing unit 540 was maintained in an inert atmosphere, or the oxygen concentration was maintained at 5%, or the room temperature compressive strength or metallization ratio did not significantly differ. Since the internal space of the smoothing unit 540 is maintained at a completely inert atmosphere (oxygen concentration of 0%), the process cost is greatly increased. Therefore, the oxygen concentration can be selected to be 5% or less.

At the end of the firing furnace 500, a cooling portion 550 is provided. The homogeneous heat-treated intense light in the homogenizing unit 540 is discharged to the cooling unit 550, cooled, and then discharged to the outside to become a partially reduced iron. In order to suppress or prevent the reoxidation of the reduced iron as much as possible, the coarse light which has been maintained at 1000 ° C. to 1200 ° C. in the smoothing unit 540 is quenched to about 400 ° C. or lower, Deg.] C to exit the cooling unit 550. The cooling unit 550 may be divided into a plurality of spaces to control the temperature and the oxygen atmosphere.

On the other hand, the atmosphere in the inner space of the sintering furnace (the reducing part, the smoothing part, etc.) includes a drying part 510, a volatile fraction removing part 520, a reducing part 530, a smoothing part 540, a cooling part 550, And an atmospheric control unit 560 connected to the connection pipe and controlling the oxygen concentration by supplying atmospheric gas including air, oxygen, inert gas, carbon dioxide gas, and the like to the inner space through the connection pipe . The exhaust gas generated from the outside air or the oxygen gas and the inert gas or the drying unit 510, the volatile fraction removing unit 520, the reducing unit 530, the equalizing unit 540, and the cooling unit 550, Carbon monoxide gas or carbon dioxide gas contained therein may be mixed and used as an atmospheric gas. Particularly, in the case of the exhaust gas generated in the reducing unit 530, since the oxygen concentration is low in the process of reducing the iron ore and is a high-temperature gas capable of raising the intense light to a high temperature of about 800 ° C, Air and the like are controlled to a predetermined temperature and then used as a source of thermal energy required for the drying unit 510, the volatile fraction eliminating unit 520, the reducing unit 530, the equalizing unit 540 and the cooling unit 550 Thereby reducing the overall process cost.

A method for manufacturing partially reduced iron according to an embodiment of the present invention includes the steps of drying a plurality of compacted light including a carbonaceous material and an iron material, removing volatile components contained in the plurality of compacted light, Treating at least a portion of the iron raw material by heat treatment; Uniformizing a plurality of compacted light beams for heat-treating the reduced plurality of compacted light at a second temperature lower than the first temperature, and cooling the plurality of heat-treated compacted light beams. The second temperature of the step of homogenizing can be selected in the range of 1000 ° C to 1200 ° C.

At this time, the oxygen concentration in the homogenizing step is maintained such that the oxygen concentration is lower than the oxygen concentration in the step of supplying and reducing atmospheric gas containing at least one selected from oxygen, air, inert gas, or carbon oxide gas . Also, the oxygen concentration in the homogenizing step can be kept at 5% or less.

Further comprising the step of: stacking the plurality of intense light beams on the carriage so as to have a predetermined height, wherein during the reducing and smoothing step, heat is applied to one side (e.g., upper side) .

The ending point of the step of reducing the plurality of compacted lights can be set based on confirming that the metallization rate is maximally ensured. The temperature of the step of reducing after the reduction step is completed, the temperature lower than the oxygen concentration and the oxygen concentration It is possible to carry out the homogenization step by heat-treating the partially reduced intense light in the atmosphere of FIG.

According to the present invention, since the partial reduced iron has a room temperature compressive strength of 150 kgf / p or more and a metallization ratio of 45% or more, it has a room temperature compressive strength sufficient for use in the blast furnace method and has a high metallization rate, Can produce molten iron.

In the embodiment of the present invention, after reducing a plurality of intense light (carbonaceous intraneous light) containing a carbonaceous material and an iron raw material, a homogenization heat treatment is performed at a lower temperature and an oxygen concentration at the time of reduction, It is possible to simultaneously improve the performance of the system. In addition, it is possible to manufacture a partially reduced iron without fluctuation in the compressive strength at room temperature or the metallization rate depending on the heights of the plurality of compacted light stacks stacked on the truck. As a result, it is possible to reduce energy consumption in a stable manner in the blast furnace.

Although the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be defined by the appended claims and equivalents thereof.

100, 200: Hopper 300: Mixer
400: compacting optical molding machine 500: firing furnace
510: Drying section 520: Volatile fractionating agent
530: Reduction unit 540:
550: Cooling section 560: Atmosphere control section
600: Partially reduced iron

Claims (15)

A reducing unit for heat-treating a plurality of compacted light including a carbon material and an iron raw material at a first temperature to reduce at least a part of the iron raw material; And
And a smoothing unit connected to a downstream end of the reducing unit and for heat-treating the reduced plurality of intense light at a second temperature lower than the first temperature,
The oxygen concentration in the homogenizer is maintained to be lower than the oxygen concentration in the reducing section,
The second temperature is higher than or equal to 1000 ° C and lower than or equal to 1200 ° C,
And the plurality of intense light beams are heat-treated in a non-fusion state in the uniforming section.
The method according to claim 1,
A drying unit connected to a front end of the reducing unit to dry the plurality of compacted lights, and a volatile fraction removing unit to remove volatile components contained in the plurality of compacted lights; And
And a cooling unit connected to a rear end of the smoothing unit and cooling the plurality of intense light heat-treated.
The method according to claim 1,
A reducing section connected to the reducing section and the equalizing section,
Further comprising an atmosphere control unit for supplying an atmospheric gas containing air to the reducing unit and the smoothing unit to control the oxygen concentration in the reducing unit and the smoothing unit.
delete The method according to claim 1,
Wherein during the heat treatment of the plurality of intense light, the oxygen concentration in the homogenizer is maintained at 5% or less.
delete The method according to claim 1,
Wherein the plurality of compacted lights are stacked so as to have a predetermined height on a bogie moving along a moving path communicating with the reducing unit and the smoothing unit,
And a heat source provided on one side of the movement path.
Heat treating the plurality of compacted light including the carbonaceous material and the iron raw material at a first temperature to reduce at least a part of the iron raw material; And
And uniformizing the plurality of compacted light beams for heat-treating the reduced plurality of compacted light at a second temperature lower than the first temperature,
The oxygen concentration in the homogenizing step is maintained to be lower than the oxygen concentration in the reducing step,
The second temperature is higher than or equal to 1000 ° C and lower than or equal to 1200 ° C,
Wherein the plurality of compacted light is heat-treated in a non-fusion state in the uniforming step.
The method of claim 8,
Further comprising the step of drying the plurality of compacted light beams before the reducing step and removing the volatile components included in the plurality of compacted light beams,
Further comprising the step of cooling the plurality of intense light heat-treated after the homogenizing step.
delete The method of claim 8,
Wherein the oxygen concentration is controlled by supplying atmospheric gas containing at least one selected from oxygen, air, an inert gas, and a carbon oxide gas.
The method of claim 8,
Wherein the oxygen concentration in the homogenizing step is maintained at 5% or less.
delete The method of claim 8,
Further comprising the step of stacking the plurality of intense light beams on the carriage so as to have a predetermined height,
Wherein the heat is supplied in one direction of the bogie moving along the movement path during the reducing and equalizing steps.
A method for producing a partially reduced iron according to any one of claims 8 to 9, claim 11 to 12, and claim 14,
Partially reduced iron having a room temperature compressive strength of 150 kgf / p or more and a metallization ratio of 45% or more.

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