KR101666059B1 - pellet and the method of manufacturing sintered ore using it - Google Patents

Abstract

The present invention relates to a pellet contained in a granule for sintering and a method for producing a sintered ore using the same. The present invention relates to a method for producing a sintered ore having a pellet A process for producing a pellet containing burnt lime and limestone mixed with iron ores and minerals or iron ores to reduce the melting point of the pellets, a process for preparing sintered granules by mixing the sintered blend materials and pellets, and a process for sintering the sintered granules To thereby increase the strength and reduction ratio of the sintered ores.
That is, the content of limestone and quicklime is controlled during the production of the pellets to reduce the melting point of the pellets in the sintering granule so that the pellets melt before other iron ores constituting the sintering granule.
Therefore, when the sintering granules are sintered, the pellets are melted more than the iron ores in the sintering granules which are not included in the pellets, and spread evenly between the granules for sintering, thereby increasing the bonding force (bonding force) Lt; / RTI >
In addition, since the pellets are first melted in the sintering granule, the excessive melting of the iron ores not contained in the pellets can be suppressed, and the proportion of the iron ores remaining in the sintered ores can be increased and the reduction ratio of the sintered ores can be increased It is possible to reduce the cost required to introduce the reducing agent to induce the reduction of the sinter ores in the blast furnace.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pellet and a method of manufacturing the same,

The present invention relates to a pellet and a method for producing the sintered ore using the pellet. More particularly, the present invention relates to a pellet which can increase the reactivity of a mini-pellet contained in a sintered granule, And a method for producing sintered ores.

Generally, the sinter ore used as a raw material in a blast furnace is produced by mixing iron ore, an additive, coal as a heat source, and then burning coal to sinter the iron ore as heat. That is, the sintered ores are prepared by mixing and mixing iron ore, a mixture of a raw material and a solid fuel, and charging the sintered powder into the sintering machine. When the air is sucked from the lower portion of the sintering machine by suction force, the coke contained in the granulated product comes into contact with oxygen in the air, And as the flame advances, the sintering raw material charged into the sintering furnace is sintered. Through this process, the semi-molten sintered ores are produced and transported to a blast furnace (blast furnace) which is a post-process which is the sintered ore produced.

At this time, the amount of low-grade iron ore used is increased due to the continuous depletion of high-quality iron ore resources among the iron ores constituting the sinter ores, so that the quality and productivity of the sintered ores are improved by utilizing low-grade iron ore resources, Development of technology is required.

Mineral iron ore is a typical resource of low-grade iron ore, and the average particle size is less than 0.1 mm because of the very high fraction of fine grains below 200 μm. Therefore, when the minute iron ore is directly used as the raw material for sintering, the air permeability in the sintering machine bed is deteriorated, and the productivity of the sintering is drastically reduced.

2, in order to use a minute iron ore as a raw material for sintering, a minute iron ore is introduced into a high-speed agitating mixer 500, and thereafter the pelletizer 600 is assembled to form a mini-pellet Is mixed with the sintering blend materials mixed in the first mixer (200) and fed to the sintering apparatus (400) in the state of sintering granules, and the sintering process is performed .

However, the use of the sintering blend raw materials by assembling the mined pellets with the mined pellets is effective only in that it can be used as the sintering blend raw material, and the increase in the quality (strength and reduction ratio) of the final produced sintered ores And the sintering productivity is further reduced.

KR 2001-0068604 A1 KR 2001-0085467 A1 KR 2011-0138044 A1

The present invention provides a pellet capable of solving a decrease in sintering productivity due to the use of a minute iron ore, and a method for producing a sintered ore using the same.

The present invention provides a pellet capable of increasing the strength and reducing rate of sintered ores to increase the quality of sintered ores and reducing the amount of the reducing agent used in the blast furnace, and a method for producing sintered ores using the same.

The pellets included in the sintering granular material according to the embodiment of the present invention are characterized in that the pellets are composed of a minute iron ore and a minute iron ore having an average particle size larger than that of the minute minute iron ore and the minute iron ores and the minute iron ores, Includes burnt lime and limestone to reduce.

The content of the quicklime and the limestone may be CaO / Fe ₂ O ₃ molar ratio of 0.5 to 0.75 in the pellet.

The whole of the quicklime may be included in the pellets in the whole amount of the quicklime to be mixed with the granules for sintering.

The limestone may include 12.9 to 30% based on the total content of limestone mixed in the sintering granule.

The particle size of the pellets may be 1 mm or more and 6 mm or less.

The melting temperature of the pellets may be between 1180 and 1250 ° C.

The method of producing an sintered ore according to an embodiment of the present invention includes the steps of mixing a plurality of sintering blend materials, and mixing the sintered blend materials with the sintered rare-earth iron ores, the minute iron ores having a particle size larger than that of the minute iron ores, Preparing sintered granules by mixing the raw materials for sintering and pellets; and sintering the granules for sintering to produce sintered ores.

The process of preparing the pellet includes a step of preparing a raw material for selective assembly including the minute iron ore, the minute iron ore, the quicklime and the limestone, and a process of mixing the raw materials for selection and pelletizing And the calcium oxide and limestone may be prepared so that the CaO / Fe ₂ O ₃ molar ratio of the raw material for selective granulation has a value of 0.5 to 0.75.

The calcium oxide contained in the sludge granules is added to the mini pellet in the manufacturing process of the mini pellet, and the limestone is present in an amount of 12.9 to 30% based on the total limestone content contained in the sinter granule, It can be put into the manufacturing process.

The melting temperature of the pellet is from 1180 to 1250 ° C, and the pellet is mixed with the sintering blend raw material to inhibit melting of the ore contained in the sintering blend raw material.

According to the pellet according to the embodiment of the present invention and the method of producing sintered ores using the sintered material, the pellet for sintering is prepared by mixing and assembling the pellets having increased reactivity and the sintering blend material, And it is possible to increase the quality (strength and reducing property) of the produced sintered ores.

That is, the molar ratio of CaO / Fe ₂ O ₃ in the pellets is controlled by controlling the content of limestone and quicklime in the production of pellets, and the molar ratio of CaO / Fe ₂ O ₃ is controlled to control the melting point of the pellets So that the pellets are melted before other iron ores constituting the sintered granule.

Therefore, when the sintering granules are sintered, the pellets are melted more than the iron ores in the sintering granules which are not included in the pellets, and spread evenly between the granules for sintering, thereby increasing the bonding force (bonding force) Lt; / RTI >

In addition, since the mini pellet is first melted in the sintering granule, excessive melting of the iron ores not contained in the pellets in the sintering granule can be suppressed, and the proportion of iron ores remaining in the sintered ores can be increased. Thus, by increasing the reduction ratio of the sintered ores, it is possible to reduce the cost required to introduce the reducing agent to induce the reduction of the sintered ores in the blast furnace.

FIG. 1 is a flowchart showing a conventional sintered light producing process.
FIG. 2 is a flowchart showing a sintering process in the case where pellets are additionally used in a conventional sintered light production process.
FIG. 3 is a flowchart illustrating a pellet according to an embodiment of the present invention and a method for manufacturing sintered ores using the same.
FIG. 4 is a graph showing sintering time of a conventional sintered light production process using pellets manufactured according to an embodiment of the present invention.
FIG. 5 is a graph showing sintering productivity of a conventional sintered light production process using pellets manufactured according to an embodiment of the present invention.
FIG. 6 is a graph showing the sintered light intensity and the reduction ratio produced by the conventional sintered light production process using the pellets manufactured according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

The pellet according to an embodiment of the present invention and the method of producing sintered ores using the same can produce sintered ores having increased sintering productivity and improved quality by using pellets having increased reactivity.

Hereinafter, a pellet according to an embodiment of the present invention and a method for producing a sintered ores using the same will be described with reference to FIGS. 3 to 6. FIG. Here, FIG. 3 is a flowchart illustrating a pellet according to an embodiment of the present invention, and a method of manufacturing a sintered ore using the same. FIG. 4 is a graph showing sintering time of a conventional sintered light production process using pellets manufactured according to an embodiment of the present invention. FIG. 5 is a graph showing sintering productivity of a conventional sintered light production process using pellets manufactured according to an embodiment of the present invention. FIG. 6 is a graph showing the sintered light intensity and the reduction ratio produced by the conventional sintered light production process using the pellets manufactured according to the embodiment of the present invention.

Referring to FIG. 3, the method for producing sintered ores according to an embodiment of the present invention includes a step of mixing a plurality of sintering blend materials, a step of mixing the sintering blend raw materials with each other, A process for producing pellets by using quicklime and limestone to reduce the melting point, a process for preparing sintering granules by mixing the sintering blend material and pellets, and a process for sintering the sintering granules by sintering the granules for sintering. That is, in the present invention, it is considered that the present invention is characterized in that the iron ores having a larger average particle size than the iron ores having a minute particle size and the iron ores having a larger average particle size than the minute minute iron ores are mixed with the minute iron ores and the iron ores, The present invention also provides a method for producing sintered ores having increased sintering productivity and quality by using the same. The mini pellet according to the embodiment of the present invention and the process for producing the sintered ores using the mini pellet will be described in more detail as follows.

On the other hand, generally, when a sintered ores are produced by using a minute-sized raw material, a minute pellet is referred to as a mini-pellet. Therefore, in the following, the meanings of the pellets and the mini pellets are the same even if they are used in combination.

First, the raw material for sintering composed of iron ore, additives, semi-light, fuel and the like is prepared in the storage hopper 100. Here, the iron ore can use any one or two or more selected from hematite, maltite, magnetite and Marra Mamba, and the contents of hematite, maltite, magnetite and Marra Mamba iron are slightly different from each other . Further, the additive material may include at least one of limestone, quicklime, silica, serpentine, etc., and the fuel may include at least one of coke, anthracite, and the like.

In addition, as a raw material for selective assembly for manufacturing the mini pellet, a minute iron ore, minute iron ore, quicklime and limestone are prepared. Herein, the minute iron ore has a particle size of less than 0.1 mm, and the minute iron ore has a larger particle size than the particle size of the minute iron ore and can exhibit an average particle size of 2.0 to 4.0 mm. In the case of minerals and minerals, minerals or iron ores act as core particles of minerals and iron minerals. Mineral minerals are attached to the surface of iron ores with relatively large grain size. Can be produced

At this time, when the particle size of the minute iron ore exceeds 4 mm, the absolute amount of minute iron ore that can act as a seed particle at the time of selective granulation is small, and in some cases, the minute minute iron ores are assembled with each other, Problems can arise. Accordingly, the minute iron ore and the minute iron ore can be provided with a particle size or a content capable of designating minute iron ore as nuclear particles and suppressing or preventing the minute minute iron ores from being assembled by themselves.

In addition, CaO-containing burnt lime and limestone are mixed with the minerals iron ore and iron ore to prevent the mini-pellet particles from collapsing during the sintering process and to lower the melting point of the mini-pellets, It is possible to suppress or prevent the iron ores of the blended raw material from being excessively melted. By controlling the molar ratio of CaO / Fe ₂ O ₃ in the sintered granule, the above-mentioned quicklime and limestone can reduce the melting point of the mini pellet and increase the sintering intensity and reduction ratio, which are most important in the present invention.

That is, the quicklime and limestone containing CaO can be adjusted so that the molar ratio of CaO / Fe ₂ O _{3 in} the mini pellet has a value within the range of 0.5 to 0.75. At this time, in order to satisfy the molar ratio of CaO / Fe ₂ O ₃ , the entire amount of the quicklime to be mixed in the sludge granules can be used in manufacturing the mini pellets. That is, when the total amount of burnt lime injected into the sintering granule is 100, the 100% of the quicklime can be used to adjust the CaO / Fe ₂ O ₃ molar ratio of the mini pellet when the mini pellet is manufactured. The reason why the total amount of the quicklime contained in the sintered granule is used in the preparation of the mini pellet is that when the CaO / Fe ₂ O ₃ molar ratio is controlled, the CaO component value is controlled to control the component value of CaO from limestone It is easier than doing.

On the other hand, since the entire content of the quicklime to be mixed with the granulated sludge is used at the time of manufacturing mini pellets, the limestone used at the time of manufacturing mini pellets is charged at the time of manufacturing mini pellets according to the amount of quicklime, CaO / Fe ₂ O ₃ molar ratio can be controlled. At this time, when the total content of limestone mixed in the sintering granule is 100%, the limestone mixed in the granulation for sintering may be used as a raw material for selective granulation in the production of mini pellets. That is, the total content of limestone in the mini pellet is 12.9 to 30% based on the total content of limestone mixed in the sintering raw material, and the remaining content is assembled into pseudo-particles together with the sintering raw material. Thus, the total content of limestone can be made to be 100% in the granules for sintering by mixing the pellet assembled with the sintering material and the mini pellet.

The reason why the CaO / Fe ₂ O ₃ molar ratio in the mini pellet is limited to 0.5 to 0.75 in relation to the content of the quicklime and the limestone is that it is related to the strength and the reduction ratio of the sintered ores produced by the mini pellet according to the change of the molar ratio Lt; / RTI > That is, when the molar ratio of CaO / Fe ₂ O ₃ in the mini pellet has a value less than 0.5, the reduction rate of the sintered ores is lowered. When the molar ratio of CaO / Fe ₂ O ₃ exceeds 0.75, The CaO / Fe ₂ O ₃ molar ratio in the mini pellet can exhibit a value of 0.5 to 0.75 since the sintered ores that satisfy the above range are sharply lowered.

At this time, when the CaO / Fe ₂ O ₃ molar ratio is less than 0.5, the reduction ratio of the sintered ores is lowered because the CaO content of the mini pellet is lowered. That is, the quicklime means that the total content is used in the mini pellet but no limestone is added so as to satisfy the molar ratio. As a result, the reactivity of the mini-pellets, that is, the effect of lowering the melting point with respect to heat, can not be achieved. Therefore, when the sintering is performed by mixing with the sintering blend material, the melting reaction of the remaining iron ores contained in the sintering blend material first appears, This is because the reduction ratio of the sintered ores is decreased because the ratio of the iron ores present is lowered.

On the other hand, when the CaO / Fe ₂ O ₃ molar ratio exceeds 0.75, the reason why the strength of the sintered ores is sharply lowered is that CaO / Fe ₂ O ₃ The increase in the molar ratio means that the amount of burnt lime and limestone added to the raw material for selective assembly for manufacturing the mini pellet is increased. More specifically, it means that the amount of limestone introduced into the mini pellet is out of the range of 19.9 to 30% and exceeds 30%. In this way, almost all of the burnt lime and limestone used in the production of the sintered ores, , The melting reactivity of the mini pellet is increased when the sintering raw material and the mini pellet are mixed, but the melt reactivity of the iron ores contained in the sintering raw material is extremely lowered. In the case of mixing the mini- pellets and the sintering raw materials, It is not easy to increase the packing density between the pellets and the sintering blend raw material, so that the strength is lowered and the melting property of the iron ores is lowered, so that in the iron ores used for the sintering raw materials, The melt of the molten liquid does not spread evenly, and some of the excessively bonded regions exist. Which is due to the problem that the strength is lowered by a relatively small binding domain indicates occurrence.

As described above, the particle size of the mini pellet produced by pelletizing with the pelletizer 600 at a high molar ratio by mixing CaO / Fe ₂ O ₃ in a high-speed agitating mixer 500 is from 1 mm to 6 mm And the melting point of the mini pellet during sintering may range from 1180 to 1250 ° C. At this time, when the particle size of the mini pellet is less than 1 mm, the effect of improving the air permeability inside the sintering bed of the sintering apparatus 400 can not be expected. When the particle size exceeds 6 mm, the particle size of the mini pellet itself The mini pellet can be manufactured to have the above-mentioned range of particle size because it is not easy to realize mini pellet melt at low temperature, which is an effect to be achieved by the present invention, and to combine with the sintering raw materials using the mini pellet melt.

When the mini pellet is completed, the mini pellet and the remaining sintering ingredients are mixed with pseudo-particles of the sintering raw material first assembled in the first mixer 200, To produce granules for sintering. Here, the sintering granules have a larger particle size than the particles of the mini pellet, and the sintering granules have a particle size larger than that of the first pelletized granules in the first mixer 200. That is, the sintering granule is a final assembly before the sintered ores are manufactured by mixing and assembling the pellet and the mini pellet, which are first assembled by the sintering blend materials, before being sent to the sintering apparatus 400.

The sintered granules thus produced are sent to a sintering apparatus 400 for sintering. The mini pellets of the present invention are characterized in that the mini pellets are first melted The iron ores become residual light in the sintered ore to increase the reduction ratio of the sintered ore and the mini-pellets are melted and diffused in the sintered assembly light, so that a sintered light in a firmly bonded state can be obtained.

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

The overall test was carried out using a sintering simulator (sintering POT) simulating the conditions of the site. The results were compared with those of the sintered light without using the minerals or with the mini pellets obtained by assembling only the minerals The sintering time (min) and the sintering productivity (t (t)) were measured in the case of the comparative example in which the sintered ores were made by using the mini pellets obtained by controlling the molar ratio of CaO / Fe ₂ O ₃ / d / m2), the sintered light intensity (%), and the sintered light reduction ratio (%).

That is, according to the blending ratio shown in [Table 1], the sintering material (standard, STD) passing through the process flow chart of FIG. 1 and the minute minute iron ores are used without using the minute minute iron ore, The iron ore of miniscule iron was mini- peled with the CaO / Fe ₂ O ₃ molar ratio controlled by the combination of the minerals iron ore, calcined limestone and limestone through the sintering raw material (comparative example) (Sintering time, productivity, strength and reduction ratio) of the sintered ores produced using each of the sintered starting materials (examples) containing the pellets are confirmed.

standard
(STD) Comparative Example Example A combination B combination A combination B combination hematite 23.51 19.98 - 19.98 - Platelets 34.03 28.92 - 28.92 - Mara Mamba Light 6.31 5.37 - 1.26 4.11 Microscopic spectroscopy - - 9.58 - 9.58 Limestone 10.2 10.20 - 8.88 1.32 quicklime 1.81 1.81 - - 1.81 burr 0.20 0.20 - 0.20 - Reflection 19.64 19.64 - 19.64 - hard coal 2.15 2.15 - 2.15 - cokes 2.15 2.15 - 2.15 - sum 100 100 100

In Table 1, A indicates the raw material for sintering which is firstly assembled in the first mixer 200 and transferred to the second mixer 300, and B is a raw material for optional assembly, That is, the blend material transferred to the second mixer 300 through the high-speed stirring mixer 500 and the pelletizer 600.

In other words, the sintered orbital was manufactured without using the microscopic spectroscopy, and the comparative example was manufactured by mini-pellet only by selecting and assembling the microscopic spectroscopy. Examples include microscopic spectroscopy, pulverulent light for increasing the assembling force of the microscopic spectroscopy, To increase the reactivity, it is a blending ratio for preparing a mini pellet in which the molar ratio of CaO / Fe ₂ O ₃ is adjusted to 0.5.

As described above, the change of the intensity and the reduction ratio of the sintered ores to the change of the molar ratio of CaO / Fe ₂ O ₃ in the mini pellet can be confirmed from [Table 2].

CaO / Fe ₂ O ₃ mole ratio in mini pellets 0.00 0.25 0.50 0.75 1.00 1.25 1.50 burglar(%) 73.0 73.5 74.1 73.4 72.5 70.0 67.8 Reduction rate (%) 62.4 66.4 68.5 70.9 70.1 67.8 65.9

That is, as shown in [Table 1], CaO / Fe₂O₃ When the molar ratio is 0, no quick lime and limestone are added at the time of manufacturing the mini pellet, so that the thermal reactivity of the mini pellet is not increased, so that the melting rate of the iron ores contained in the sintering raw material is excessively high. And CaO / Fe in the mini pellet₂O₃ As the molar ratio increases, the strength and reduction rate tend to increase. When the molar ratio exceeds 0.75, the strength and the reduction ratio are lowered, and thus a problem arises in the case where the range of the molar ratio does not satisfy the range defined in the present invention The above data can be confirmed.

The characteristics (sintering time, productivity, strength, and reduction ratio) of the sintered ores produced using each of the raw materials thus prepared are as shown in Table 3 below.

Sintering time
(min) Sintering productivity
(t / d / m2) Sintering intensity
(%) Sintering Reduction Rate
(%) Standard (STD) 32.5 34.6 72.5 65.8 Comparative Example 35.2 30.2 73.0 62.4 Example 31.3 35.1 73.4 70.9

Here, the sintering productivity, the rotational strength and the reduction ratio of the mini pellet were determined by the well-known mathematical equations, and the sintering time was determined based on the time when the exhaust gas reached the maximum temperature.

As shown in [Table 3], when sintering time is increased by 2.7 min (min) when mini-pellets are assembled with the minutiae iron ore minus the reference condition (without using min. Iron ore) and sintering time is increased, sintering productivity 4.3 t / d / ㎡ is lowered. On the other hand, the sintered light intensity is 73%, which is equal to or higher than the reference condition, but the reduction rate tends to decrease by about 3%. This is because, in the case of the comparative example, the melting rate of the iron ores contained in the sintering raw material is lower than that of the mini pellet when the mined pellets are produced using the mined iron ore.

Based on the above results, in the case of the embodiment using the mini pellets in which the blended raw materials and the blending ratio are controlled in the present invention, it is preferable that the melting temperature of the mini pellet is in the range of 1100 to 1250 ° C, It can be melted at a lower temperature than it melts at a temperature. As a result, the sintering time is reduced by a predetermined time (1 minute to 2 minutes) compared to a reference condition (no use of a minute iron ore) and the sintering time is decreased, It was found that the sintering productivity of the comparative example was increased by 5t / d / m < 2 > than that of the comparative example, and the productivity was greatly improved. Also, the sintered light intensity is 73.4%, which shows higher strength than the reference condition and the comparative example, and the reduction rate tends to increase to 5% of the reference condition and 8% or more of the comparative example. This is because the sintering time can be shortened due to the low melting point as compared with the blending raw materials of the reference conditions and the B blending raw materials of the comparative examples and the mini pellets having a low melting point serve as bonding necessary for securing the strength of the sintered ores, It is believed that the excessive reduction in melting is caused to manifest the reducing property inherent in the ore.

As described above, the pellets according to the embodiments of the present invention and the method for producing sintered ores thereof using the same raw materials as those of the conventional (reference conditions, comparative examples) can control the blending raw materials and the ratio for producing the mini pellets, The sintering productivity can be improved.

Since the mini pellets have a lower melting point than iron ores contained in the sintering raw material during sintering and have a high fluidity at the time of melting, the iron ores contained in the sintering raw material are prevented from being melted first, . Thus, it is possible to improve the strength and the reduction ratio which greatly affect the quality of the sintered ores.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

100: first mixer 200: second mixer
300: Sintering machine 400: High-speed stirring mixer
500: Pelletizer

Claims (10)

delete delete delete delete delete delete Mixing a plurality of sintering ingredients;
A process of producing pellets by using minute iron ore, minute iron ore having a particle size larger than that of the minute iron ore, and calcium oxide and limestone for reducing the melting point of the minute iron ore and the iron ore;
Mixing the sintering blend raw material and the pellet to prepare a granulated product for sintering; And
And sintering the granules for sintering to produce sintered ores. The method of claim 7,
The process for producing the pellet comprises:
Preparing a raw material for selective assembly including the above-mentioned minute iron ore, said iron ore, said quicklime and said limestone;
And mixing the raw materials for selective assembly and pelletizing the mixture,
Wherein the quicklime and the limestone are provided such that the CaO / Fe ₂ O ₃ molar ratio of the raw material for selective assembly has a value of 0.5 to 0.75. The method of claim 8,
Wherein the quicklime contains the entire amount of the quicklime contained in the granulated product for sintering,
Wherein the limestone is added to the pellet in an amount of 12.9 to 30% based on the total amount of the limestone contained in the granulated product for sintering. The method according to claim 8 or 9,
In the course of producing the sintered ores by sintering the granules for sintering,
Wherein the pellet is melted at 1180 to 1250 占 폚 to inhibit melting of the iron ores contained in the sintering and blending raw material.

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