JP2007107102A - Method for transportation of reproduced desulfurization agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable reduction of hot metal desulfurization cost and slag generation; to provide a hot metal desulfurization method, which also leads to a solution to environmental problems, by the reduction of the slag generation. <P>SOLUTION: The present invention is a method to reuse desulfurizaion slag generated in KR desulfurization process of hot metal as desulfurization agent. The method conducts a process to create new interface for desulfurization slag generated in desulfurization of hot metal by a mechanical stirrer process. The method comprises; a process to prepare desulfurization slag generated in KR desulfurization; and a process to create new interface for the prepared desulfurization slag. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an apparatus used in a method for producing a hot metal desulfurization agent that effectively reuses the desulfurization hot metal (KR) generated in the mechanical stirring type hot metal pretreatment process.

Although the hot metal discharged from the blast furnace usually contains a high concentration of sulfur (S) that adversely affects the quality of the steel, the converter process is intended for the purpose of oxidizing and removing impurities. Except for partial vapor desulfurization, desulfurization of molten steel is not expected. Therefore, depending on the required quality, molten steel desulfurization is performed in various hot metal pretreatments in the process between the blast furnace and the converter and in the subsequent process of the converter. FIG. 23 shows an example of the hot metal preliminary treatment. In the example shown in the figure, the hot metal from the blast furnace is subjected to de-Si treatment, de-S treatment, and de-P treatment in this order, and then put into a converter and de-C treatment.

In desulfurization, a lime-based desulfurization agent is often used, and the desulfurization reaction in this case proceeds according to the reaction formula shown below.

CaO + S → CaS + O
Such a desulfurization reaction has a high melting point in the case of CaO alone, and industrially, fluorite, an alumina-based fossilizing agent, and the like are generally used for promoting lime hatching. However, these slagging agents are generally expensive, and increasing the blending ratio of these slagging agents leads to an increase in the desulfurization agent cost. Furthermore, there is a concern that when the blending ratio of the koji-making agent is increased, the lime concentration in the desulfurizing agent is lowered and the reaction effect is lowered.

In addition, slag produced in dry refining processes such as blast furnaces and converters is reused as blast furnace cement, concrete material, fertilizer, road material, etc. after removing the metal. However, desulfurized soot has a high CaO content and is easily weathered. Therefore, it takes a lot of time for pretreatment to make a cement raw material. Moreover, the current situation is that the processing is costly.

Japanese Patent Application Laid-Open No. 4-120209 describes a technique for using a converter fossil as a slagging agent. Here, it is stated that the particle size of the converter rod is defined as 3 to 50 mm, and that a sufficient dephosphorization effect is obtained with a particle size in this range. However, it is not intended for desulfurization and nothing is mentioned about desulfurization.

Japanese Patent Laid-Open No. 10-30115 discloses a technique in which lime and fluorite are blended in a converter dredger that has been cooled and crushed to separate and collect iron, and used as a desulfurizing agent. There is no mention of reusing desulfurized soot as well.

As an example of recycling of desulfurized slag, there has been reported a process of reusing injection desulfurized slag having a large amount of unreacted lime for mechanically stirred hot metal desulphurization with excellent lime utilization efficiency (Sumitomo Metals Vol. 45-3). (1993) p.52-58). However, the treatment reported here (hereinafter referred to as the prior art of desulfurization soot recycling) has a limit in improving the utilization efficiency of lime as will be described later, and it can be reused for processes with different addition and stirring methods. Therefore, it cannot be applied when there are no multiple processes.

In addition, the mechanical stirring type hot metal desulfurization device is a device that immerses and rotates the impeller (impeller) in the hot metal, adds a desulfurizing agent (usually lime) from the upper part of the hot metal, and desulfurizes the hot metal by stirring by the impeller rotation. As a hot metal desulfurization process using this apparatus, there is a so-called KR method. FIG. 24 shows an example of the S removal equipment.

As described above, the desulfurized soot obtained by the hot metal desulfurization treatment is not effectively reused, and there are many points that require improvement when desulfurizing the hot metal.

  The present inventors investigated the utilization efficiency of the desulfurization agent utilized in the KR desulfurization process. FIG. 18 shows a case where the desulfurized soot obtained by the mechanical stirring type hot metal desulfurization treatment method is used as a desulfurizing agent in the mechanical stirring type hot metal desulfurization processing method, and a case where the desulfurized soot obtained by the injection method is used. It is a figure which shows the comparison of the ratio of the lime utilized effectively for desulfurization with respect to input lime about the case where it uses as a desulfurization soot. As shown in FIG. 18, it was found that the utilization efficiency of the desulfurization agent used in one use of the KR desulfurization process was about 7%, and the remaining 93% remained unreacted. . Therefore, from this knowledge, the inventors reused this lime content because the desulfurization agent after being used in the KR desulfurization treatment process still contains about 93% of the lime content contributing to the desulfurization of the next treatment. If possible, we thought that it could be expected to be used as an inexpensive lime source for desulfurization agents.

The present invention has been made based on this finding, and it is possible to effectively reuse the desulfurized soot obtained by the hot metal desulfurization treatment, thereby reducing the hot metal desulfurization cost and the generation amount of slag. It is an object of the present invention to provide a method for transporting desulfurized iron used in the method for desulfurizing molten iron.

  This invention was made | formed to achieve this objective, The manufacturing method of the desulfurization agent for hot metal which concerns on this invention is equipped with the following processes.

1 A method for producing a desulfurization agent for hot metal, which performs a process for creating a new interface with respect to the desulfurization generated by the mechanical stirring type hot metal desulfurization process.

2 A method for producing a desulfurizing agent for hot metal used in a mechanically stirred hot metal process, wherein a process for creating a new interface is performed on the desulfurized iron produced by the mechanically stirred hot metal desulfurization process.

3. A method comprising a step of preparing a desulfurization slag generated by a mechanical stirring type hot metal desulfurization treatment, and a step of performing a process of creating a new interface on the prepared desulfurization slag.

4. The method of performing the process of creating a new interface includes crushing the desulfurized soot particles and / or separating an aggregate of the plurality of desulfurized soot particles into the desulfurized soot particles.

5. The process of creating a new interface is performed by crushing the desulfurized soot particles by air cooling and / or applying mechanical energy to the desulfurized soot, and / or A method of separating agglomerates into desulfurized soot particles.

6 The method of cooling the desulfurization soot is one or two selected from the group of air cooling and water cooling.

7 Air cooling is one or two methods selected from the group of natural cooling and forced cooling.

8 The process of creating a new interface by water cooling comprises the step of sprinkling water into the desulfurization soot, and this sprinkling process controls the amount of sprinkling so that the temperature of the desulfurization soot at the end of sprinkling is maintained at 100 ° C or higher. In this way, the desulfurization soot condensate can be separated and / or the desulfurization soot particles can be crushed only by cooling with water spray.

9 The method of performing a treatment for creating a new interface includes a step of water-cooling the desulfurization soot and a step of drying the regenerated desulfurizing agent obtained by water cooling.

10 A manufacturing method comprising a step of performing a treatment for creating a new interface, a step of cooling the desulfurization soot and a step of adjusting the particle size of the desulfurization soot and the regenerated desulfurizing agent.

11 The process of adjusting the particle size of the regenerated desulfurizing agent with a sieve is a production method performed at a temperature of 600 ° C or higher.

12 The process of creating a new interface is a process of magnetically removing the bullion contained in the desulfurization soot or regenerated desulfurization agent, removing the large mass in the desulfurization soot or regenerated desulfurization agent and reducing the particle size to 100 mm. A method comprising a step of performing one or two or more treatments selected from the group consisting of a treatment to be described below and a treatment in which the temperature of the desulfurization soot or regenerated desulfurization agent is 200 ° C. or less.

13 The method of performing the process which creates a new interface comprises the process which makes the particle size of a desulfurization soot 100 mm or less, and makes temperature 200 degrees C or less.

14 A step of loading the regenerated desulfurizing agent generated by the mechanical stirring type hot metal desulfurization treatment into a transport vehicle using a pair of movable cages that can be opened and closed, and a step of transporting the regenerated desulfurizing agent to a desulfurization processing facility by a transport vehicle Transport method of regenerated desulfurization agent.

15. A method comprising a step of sieving the regenerated desulfurizing agent after cooling and crushing to remove a large mass before or simultaneously with the step of transporting using a transport vehicle.

16 Regenerated desulfurizing agent comprising a step of loading the regenerated desulfurizing agent produced by the mechanical stirring type hot metal desulfurizing treatment into a transport vehicle having a regenerative desulfurizing agent suction capacity, and a step of transporting the regenerated desulfurized agent to the desulfurization treatment facility by the transport vehicle Transportation method.

17 The step of loading the regenerated desulfurizing agent is performed by adjusting the drop height of the regenerated desulfurizing agent to the transport vehicle within 1.5 m.

18 A regenerated desulfurizing agent comprising an apparatus main body having a screen for sieving the crushed regenerated desulfurizing agent, and an air suction hose attached to the apparatus main body and promoting suction of the regenerated desulfurizing agent into the apparatus main body. Sieving device.

19 A member having a sieve mesh arranged diagonally, a diagonal plate arranged diagonally below the member, through which the sieve passes, and a slide through which the sieve from the diagonal plate falls and passes, A regenerative desulfurization agent disposed so that the distance between the member and the diagonal plate and the vertical drop height of the connecting portion between the diagonal plate and the slide are 500 mm or less and the fall height from the slide to the ground surface is 1500 mm or less. Sieving device.

20 A desulfurization agent for hot metal, the main component of which is the regenerated desulfurization agent produced by the mechanical stirring hot metal desulfurization treatment.

21. A hot metal desulfurization agent used in a mechanical stirring hot metal desulfurization treatment, the main component of which is the regenerated desulfurization agent produced in the mechanical stirring hot metal desulfurization treatment.

22 A desulfurization agent for hot metal, the main component of which is a regenerated desulfurization agent, which is generated by a mechanical stirring type hot metal desulfurization treatment and a new interface is created.

23 A hot metal desulfurization agent mainly composed of a regenerated desulfurizing agent which is generated by mechanical stirring type hot metal desulfurization treatment and from which a part or all of the condensate of the regenerated desulfurizing agent particles is separated.

24 A desulfurizing agent for hot metal having a maximum particle size of 100 mm or less.

25. A hot metal desulfurization agent comprising as a main component a regenerated desulfurization agent produced by a mechanical stirring hot metal desulfurization treatment, and further comprising one or two selected from the group consisting of a lime source and a carbon source.

26 One or two selected from the group consisting of a lime source and a carbon source are mixed with a regenerative desulfurizing agent produced by a mechanically stirring hot metal desulfurization treatment, and this mixture is added to the hot metal. Desulfurizing agent.

27 One or two selected from the group consisting of a lime source and a carbon source and the regenerated desulfurizing agent produced by the mechanical stirring type hot metal desulfurization treatment are separated and added separately to the hot metal Desulfurization agent.

28 The lime source is a desulfurizing agent for hot metal, which is one or more selected from the group consisting of lime, calcium carbonate and calcium hydroxide.

29 The total amount of calcium carbonate and calcium hydroxide in the lime source is 40% by mass or less based on the total desulfurizing agent for hot metal.

30 The carbon source is a desulfurization agent for hot metal containing 30% by mass or less based on the total desulfurization agent for hot metal.

31 The carbon source is a hot metal desulfurization agent in a powder form of 1 mm or less.

32. The hot metal desulfurization agent, wherein the carbon source is one or more selected from the group consisting of coal, coke and pitch.

33 A method for producing low-sulfur hot metal, wherein a hot metal desulfurization agent mainly composed of a regenerated desulfurization agent produced by mechanical stirring hot metal desulfurization treatment is added to the hot metal to desulfurize the hot metal.

34. A method for producing low-sulfur hot metal in which a hot metal desulfurization agent mainly composed of a regenerated desulfurizing agent produced by mechanical stirring hot metal desulfurization treatment is added to the hot metal and the hot metal is desulfurized by mechanical stirring hot metal desulfurization treatment.

35 A method for producing low-sulfur hot metal, wherein a hot metal desulfurization agent mainly composed of a regenerated desulfurization agent, which is generated by a mechanical stirring hot metal desulfurization treatment and has a new interface, is added to the hot metal to desulfurize the hot metal.

36 A hot metal desulfurization agent mainly composed of a regenerated desulfurizing agent which is generated by a mechanical stirring type hot metal desulfurization treatment and from which a part or all of the regenerated desulfurizing agent condensate is separated is added to the hot metal to desulfurize the hot metal. Low sulfur hot metal production method.

37 A method of desulfurizing hot metal by adding a regenerated desulfurizing agent produced by a mechanical stirring hot metal desulfurization treatment and one or two selected from the group consisting of a lime source and a carbon source to the hot metal.

38 A method of mixing the regenerated desulfurizing agent produced by the mechanical stirring type hot metal desulfurization treatment with one or two selected from the group consisting of a lime source and a carbon source and adding the mixture to the hot metal to desulfurize the hot metal .

39 A method of desulfurizing hot metal by separately adding the regenerated desulfurizing agent produced by the mechanical stirring hot metal desulfurization treatment and one or two selected from the group consisting of a lime source and a carbon source into the hot metal.

40 A method of adjusting a mixing ratio so that a predetermined CaO pure content is obtained when a lime source is added.

41 a step of calculating the bulk density of the regenerated desulfurizing agent produced by the mechanical stirring type hot metal desulfurization treatment, a step of calculating the CaO pure content of the regenerated desulfurizing agent from the calculated bulk density, and the calculated regenerated desulfurizing agent of CaO pure And a step of adjusting an addition ratio of the crushed regenerated desulfurizing agent and the lime source based on the minute.

42 A method comprising a step of adjusting the particle size of the carbon source to 1 mm or less when the carbon source is added.

(Definition)
Desulfurization agent: Refers to the flux used for desulfurization in general. Also includes regenerated slag after processing to create a new interface.

Regenerated desulfurizing agent: The desulfurizing agent is composed of regenerated slag after performing a process for creating a new interface in particular, and the slag can include a metal.

Desulfurization slag: Slag before desulfurization slag containing all of CaO content, other slag content and metal content, and before processing to create a new interface.

Lime: Widely refers to CaO.

(Reuse of desulfurized soot)
In the hot metal desulfurization method of the present invention, the desulfurized iron produced in the mechanically stirred hot metal desulfurization treatment (hereinafter described as the KR method) is reused as a desulfurizing agent in another hot metal desulfurization treatment (for example, the KR method). The desulfurization soot produced in step KR is used as a desulfurization agent in the KR method, or the desulfurization soot produced in the KR method is used as a desulfurization agent in the injection method). The hot metal desulfurization treatment to be reused is not limited in any way, and refers to a normal hot metal desulfurization treatment. In the present invention, since the desulfurized soot can be reused even in the same process as the process in which the desulfurized soot is generated, the method of the present invention is an iron manufacturing method in which only a single hot metal desulfurizing treatment process is provided for the same addition method and stirring method. It is also effective in equipment. In the present invention, in particular, when the desulfurization soot reuse is applied to the KR method, the reuse efficiency is high and particularly effective.

That is, in the injection method, fine lime is added in the deep part of the bath, so that it reacts while floating in the bath. Accordingly, the reaction can be expected only for a short time, and a de-S product is formed on the very surface of the fine powder. After ascending to the bath surface, stirring such as re-entrainment cannot be expected, the reaction interface area is not increased, and almost no de-S reaction can be expected. And since aggregation starts at this stage, there exists a de-S product on the surface of each fine powder, and it will be in the form where it aggregated.

On the other hand, in the KR method, powdered lime is added to the bath surface, so that the pulverized S agent is aggregated in the vicinity of the surface from the beginning of the addition. The result is a “duck” with lime that hardly reacts inside. Even when the aggregation starts, the surface portion in contact with the metal reacts to form a de-S product. This reaction takes place during the processing time and can be performed for a long time. From the above reaction mechanism, after desulfurization, the surface of the aggregated coarse particles is covered with the desulfurization product with a certain thickness, and the inside thereof has few desulfurization products. That is, the inside becomes a form in which unreacted lime exists close to fresh lime. The inventors conducted a line analysis of a photograph obtained by observing agglomerates of desulfurized soot generated by the mechanically stirred hot metal desulfurization treatment with an SEM and S elements thereof. As a result, it was confirmed that the above findings were correct as shown in FIG.

Thus, since the desulfurization soot by the KR method is coarse, pretreatment before reuse is simple, that is, the reuse treatment cost is reduced. Further, as described above, unreacted lime often exists in an aggregated form, and can be reused without adding a special method for crushing or particle size adjustment.

On the other hand, in the desulfurization slag by the injection method, there is a de-S product around each fine powder, and special crushing or the like to further refine the fine powder is required, which increases the process and time.

As described above, in the KR method, the reaction efficiency during reuse is high. The interface of unreacted lime can be used as it is for the reaction in reuse, and the same reaction efficiency as when fresh lime is used can be expected. In reusing KR soot, the basic unit of lime is the same and can be removed. On the other hand, with an injection soot, pre-processing is complicated, or simple pre-processing requires at least double the amount of lime.

Further, when KR soot is used, the processing time can be shortened (same as the fresh agent), the effect of reducing the amount of generated slag is great, and even if it is recycled once, it is reduced by 50% and can be recycled many times.

On the other hand, in the injection method, there is a de-S product on the surface of each fine powder, and it becomes an aggregated form. For this reason, it is necessary to grind individual particles (primary particles) for reuse. The regenerated particles are very fine (less than half the primary particle size). Therefore, at the time of reuse in the KR method, the amount of scattering becomes large at the time of addition, and lime for supplementing the scattered lime content is further required. For example, in the case of only the conventional desulfurization agent used for the first time, a desulfurization agent of about 7 kg / t (internal lime content: about 90%: substantial lime content: 6.3 kg / T) is required, whereas regenerative desulfurization. In the case of using an agent, 10 kg / t (internal lime content: about 66%: real lime content: 6.6 kg / T) + conventional conventional desulfurization agent 3 kg / t (inner lime content: about 90%: real lime content: 2. 7 kg / T) is required. In other words, the lime content in the regenerative desulfurization agent is 9.3 kg / T, but the creation of an effective new interface is insufficient, or loss due to scattering occurs, so about 3 kg / T is effective. It may not contribute to desulfurization. In other words, the effective lime content in the regenerated desulfurizing agent is about 55%, and the auxiliary desulfurizing agent is added and used (Sumitomo Metals Vol. 45-3 (1993) p. 52-58). It is also described in the inside.

In the KR method, as described above, the surface of the coarse particles is covered to some extent with the de-S product, and the inside thereof has a small amount of the de-S product. That is, it becomes a form in which unreacted lime exists close to fresh lime. For this reason, a weathered product is actively produced for reuse, and the regenerated particles can be desulfurized even if they are the same size or larger than the primary particles. And at the time of reuse by KR method, the amount of scattering becomes the same as that at the time of lime use or less. For example, when a regenerated desulfurizing agent is used, the amount of regenerated desulfurizing agent used is 14 kg / t (internal lime content is about 50%), and the effective amount of lime in the added regenerated desulfurizing agent is the same as when fresh lime is added. is there.

A summary of the above relationships is shown in FIG. In the case of reusing the KR method desulfurization soot as an example of the present invention as a KR method desulfurization agent, about 7% of the lime added for each treatment is used for desulfurization, and it is effective if used many times. The utilization rate is steadily increasing. On the other hand, when the desulfurization soot of the injection method, which is the prior art of desulfurization soot recycling, is reused as the desulfurization agent of the KR method, the total utilization efficiency is only slightly higher than that of one KR.

In order to help understanding of the above description, FIG. 22 schematically showing the difference between the mechanically stirred hot metal desulfurization iron and the hot metal desulfurization iron by the injection method is attached. FIG. 22 shows a state in which desulfurized soot particles produced in the mechanically stirred hot metal desulfurization treatment are separated, and each desulfurized soot particle in the state of creating a new interface and desulfurized soot particles produced by the injection method is crushed. State. In the figure, the desulfurized soot particles produced by the injection method have substantially the same particle size as the desulfurized soot particles produced in the mechanically stirred hot metal desulfurization process, but actually are finer than that.

(Specific treatment of desulfurized soot)
FIG. 17A shows a slag processing pattern by an actual machine, and FIG. 17B shows an example of the slag processing pattern of FIG. 17A together with a conventional slag processing pattern.

In the present invention, the desulfurized soot generated in the desulfurization step is reused as a desulfurization agent after creating a new interface by an arbitrary method. In this case, it is necessary to expose the unreacted lime content as a desulfurization reaction surface when used as the next desulfurization agent. The method in that case is not restricted at all. CaCO ₃ and Ca (OH) ₂ are produced when cooling, sprinkling, and cooling processes are performed when creating a new interface. The residual of these CaCO ₃ and Ca (OH) ₂ does not particularly inhibit the desulfurization reaction, but rather an improvement in the desulfurization reaction can be expected by generating an appropriate amount. It is also possible to remove the large-diameter bullion by magnetic separation or sieving with a sieve and recover the slag mainly as a desulfurizing agent. Furthermore, the particle size of the regenerated desulfurizing agent is restricted by the supply device on the desulfurization equipment side when used, and there is no problem if an appropriate one is used. On the other hand, the regenerated desulfurization agent may have a small diameter residual metal, but it can be used again as the iron source in the next hot metal pretreatment process, so it can greatly contribute to the improvement of iron yield. There is also. Various specific examples are illustrated below.

(I) Crushing by watering treatment In this example, the desulfurized soot generated in the desulfurization process is simultaneously cooled and crushed by watering treatment and then reused as a desulfurizing agent by performing a drying treatment. Specifically, watering is performed excessively until the slag is completely hydrated by using watering equipment for hot water after the desulfurization treatment. Thereafter, the water-containing slag is completely dried using a drying apparatus to obtain a desulfurization agent having a particle size reduced to about 100 mm or less. However, the finer the particle size, the better. The maximum particle size is preferably 30 mm or less, and more preferably 5 mm or less. If necessary, mechanical pulverization may be performed before and after watering and drying. In an actual process, at least a part of the desulfurization soot is crushed by mechanical vibration during the transport of the desulfurization soot. The apparatus used for this drying may specifically be a dryer, or may be dried on a large scale using an apparatus such as a rotary kiln. Depending on the required amount of processing, the size of the apparatus, etc. As long as it can be set and the water content in the slag after cooling can be sufficiently removed, any apparatus or method can be used. The desulfurized soot thus regenerated is used as a desulfurizing agent.

(Ii) Crushing by watering / stirring treatment In this example, the desulfurized soot generated in the desulfurization process is simultaneously cooled and crushed by appropriate watering and stirring, and then reused as a desulfurizing agent. That is, using a watering facility for the hot water after the desulfurization treatment, stirring is performed by a heavy machine such as a shovel while uniformly spraying water. Specifically, water spraying is performed until the hot water is cooled to a temperature of about 100 ° C., and then the mixture is allowed to cool to room temperature, thereby obtaining a finely divided desulfurization agent having a particle size of about 100 mm or less. However, the finer the particle size, the better. The maximum particle size is preferably 30 mm or less, and more preferably 5 mm or less. If necessary, mechanical pulverization may be performed before and after watering. The cooling target temperature is not limited to a specific temperature, and the cooling target temperature can be set according to the required processing amount. The cooling time can be shortened by this appropriate amount of watering and stirring. However, if water is sprayed to 100 ° C. or lower, a drying process is required. Therefore, it is desirable to stop water spraying at 100 ° C. or higher. Further, the stirring is performed for improving the cooling rate and uniform watering, and the frequency of this implementation can be changed depending on the required processing time and amount, and may be omitted.

(Iii) Crushing by allowing to cool In this example, the desulfurized soot generated in the desulfurization step is allowed to cool and then simultaneously cooled and crushed and then reused as a desulfurizing agent. That is, the hot water after the desulfurization treatment is left in a state where the contact area with air is as large as possible, and is stirred by a heavy machine such as a shovel. Specifically, the regenerative desulfurization agent sufficiently refined to 200 ° C. or less in 3 days by spreading the hot metal to a thickness of 0.5 m or less and performing stirring about 1 to 3 times a day. Can be obtained. The thickness at the time of cooling is not limited to this thickness, and the target thickness can be set according to the required processing time and amount, the area of a place where it can be used for the regeneration process, and the like. Further, the agitation is performed to improve the cooling rate, and the frequency can be changed depending on the required processing time and amount, and may be omitted when there is a margin in the processing time and amount. . Further, a regenerated desulfurizing agent can be obtained in the same manner even when the desulfurized soot is left without being reduced in thickness.

These cooled and crushed desulfurized soot particles have a maximum particle size of 100 mm or less, preferably 30 mm or less, and more preferably 5 mm. Therefore, a sufficient surface area to participate in the desulfurization reaction can be secured. Otherwise, no scattering occurs at the time of addition, which is advantageous in terms of handling. Moreover, you may use mechanical grinding | pulverization together as needed.

(Iv) Sifting of hot cake In this example, the desulfurized soot generated in the desulfurization process is screened with a sieve (30 mm × 30 mm to 100 mm × 100 mm) while keeping the hot soot at 900 to 1200 ° C. At the same time, it is separated into a large-diameter metal containing a slag component and a small-diameter desulfurization vessel. The standard of sieving is a restriction on the supply device side when using it again as a desulfurization agent, and the above range is usually appropriate.

The small-diameter desulfurized soot after sieving is reused as a desulfurizing agent after natural cooling. At this time, about 20 to 30% of Fe content (T, Fe and metallic Fe in the slag) remains even after sieving, but is recovered to the hot metal side at the next use of desulfurization, so that the iron yield is improved.

When the large-diameter metal containing the slag component is cooled, the reaction of the following formula is caused by the unreacted lime content in the slag component.
CaO + H ₂ O = Ca (OH) ₂ CaO + CO ₂ = CaCO ₃
Since the so-called “dwelling” reaction proceeds, the slag component in the desulfurization slag collapses and can be separated into a metal part and a slag part. After this process, the above sieving may be performed again, and the desulfurized soot can be efficiently separated into large bullion (including a small amount of slag) and regenerated desulfurization agent (small diameter bullion) without performing magnetic separation. Minute). As a result, about 90% of the unreacted lime content in the desulfurized soot is recovered as a regenerated desulfurizing agent.

As long as the sieve used in this case can be used in a temperature range of 900 to 1200 ° C., an iron-made sieve is sufficient without any problem. If this sieve can be used in the desulfurization treatment plant, there are no restrictions on the shape and specifications. The sieve mesh is restricted by the supply device on the desulfurization equipment side when used as a desulfurization agent after regeneration, and there is no problem if an appropriate one is used.

As described above, desulfurized soot can be reclaimed as an inexpensive lime source by exposing unreacted lime by a simple method and making large bullion in the desulfurized soot without magnetic separation. it can. Furthermore, the regenerated desulfurizing agent using the desulfurized soot recovered after the sieving as a main raw material still has a sufficient desulfurizing ability, and lime can be used more effectively by reusing it multiple times.

(V) Suppression of dust Generation of desulfurized soot in a dry state is very easy to generate dust. However, attention was paid to the fact that most of the desulfurized soot immediately after the occurrence is a block due to high temperature. That is, after desulfurization soot is generated, if handling such as sieving at a high temperature, it can be dealt with without generating large dust. The higher this temperature is, the more advantageous it is for suppression. When the temperature was actually changed at a drop height of 3 m and the slag was dropped and the amount of dust generated was examined, it was found that the amount of dust generated suddenly increased below 600 ° C. Further, as an incidental effect of sieving at high temperature, by efficiently exposing the desulfurized soot to the atmosphere at high temperature, there is a rapid cooling of the desulfurized soot and a pulverization effect thereby, and the subsequent cooling load can be reduced.

In addition, regarding the equipment used for sieving, dust generation can be suppressed with equipment that reduces the height at which the desulfurization soot falls vertically. This equipment configuration is shown in FIG.

The equipment comprises a net (12) arranged obliquely, a swash plate (14) under which the sieve passes, and a slide (16). The feature here is that the distance (13) between the net (12) and the swash plate (14) is set to 500 mm or less in order to suppress the drop height from the desulfurization soot feeder (11). Further, the distance (15) between the swash plate (14) and the slide (16) is set to 500 mm or less. Moreover, dust generation can be greatly reduced by adopting an equipment configuration in which the drop height (17) from the slide (16) to the ground surface (18) is 1500 mm or less. By utilizing this, the dry desulfurized soot is sized with simple equipment and at low operating costs (for example, 70 mm or less), and sieving is performed at a temperature of 600 ° C. or higher. This is intended to suppress dust generation.

In addition, when the desulfurized soot that has been sized by the above method is cooled and then loaded into a dump truck for reuse, it is naturally pulverized and dust generation is very easy. This is loaded with equipment as shown in FIG. A movable cage | basket part (21) opens to both sides, and grasps | generates a regeneration desulfurization agent (22). The regenerative desulfurization agent grasped with the movable cage portion (21) closed is taken directly above the dump bed (23), and the movable portion (21) is opened there. By setting the fall height (24) at that time to be within 1.5 m, it is possible to load the dump truck while greatly suppressing the generation of dust.

(Vi) Suppression of other dust generation By the way, when the regenerated desulfurization agent that has been regenerated as described above is loaded into a transport vehicle such as a dump truck for reuse, it naturally becomes more pulverized and is very It is easy to dust. However, the generation of dust can be reduced to the maximum by using a car that has suction capability without using a truck for transporting this regenerated desulfurizing agent. At the same time, if a sieve is used at the time of suction, regeneration is simultaneously performed. Desulfurization agent can be sieved, and handling and transportation with low dust generation and high efficiency are possible.

Specifically, a suction hose is connected to a car having suction capability for the regenerated desulfurization agent after cooling and pulverizing the desulfurization soot generated in the hot metal desulfurization step, and loading is performed by suction. At this time, if a jig having a sieve mesh for sieving is used at the suction port, sieving to a required particle size is possible at the same time. Here, the jig attached to the suction port at the time of suction can be properly used depending on the required degree of sieving, that is, the required particle size of the regenerated desulfurizing agent.

Furthermore, when sieving is not necessary at the time of suction, it is possible that suction is not required at the suction port, and suction is performed only with a hose.

Furthermore, when it is necessary to remove only a large mass of several tens of centimeters, suction is performed using a simple jig in which the tip of the jig as shown in FIG. It is also possible to do. One example of the jig is shown in FIG. This jig is a simple one composed of a cylinder (1) having the same diameter as that of the hose, and a metal rod (2) attached to the tip of the cylinder (1). The mesh size of these sieves and the shape of the jig are not particularly limited, and are determined by the required particle size, pretreatment process, and the like. Further, in order to promote suction, an air suction port (3) was attached to these jigs. Using these suction jigs, loading and sieving by suction of the regenerated desulfurizing agent are simultaneously performed.

The regenerated desulfurization agent particles after cooling and crushing obtained by the treatment as described above can constitute the desulfurization agent of the present invention alone or in combination with other components as necessary. That is, the desulfurization agent of the present invention may be composed only of the regenerated desulfurization agent particles obtained in the above-described steps, and in some cases, the desulfurization agent of the present invention may be combined with other components such as lime and fluorite. You may comprise an agent. In this case, the blending amount of the other components can be appropriately determined according to the amount of lime component contained in the regenerated desulfurizing agent, the required desulfurization rate, and the like. A suitable determination method will be described later.

(Manufacture of optimum desulfurizing agent)
Next, a method for producing an optimum desulfurizing agent using the regenerated desulfurizing agent obtained from the desulfurizing soot will be described. Even with the same regenerated desulfurizing agent, the desulfurization rate varies greatly depending on the input unit. However, it was found that a good correlation with the amount of desulfurization (S before treatment-S after treatment) can be obtained by arranging the pure content of CaO in the regenerated desulfurization agent.

From this, even if the regenerative desulfurization agent component fluctuates, a stable desulfurization rate can be obtained by adding together pure CaO. Next, it is necessary to determine the CaO% in the regenerated desulfurizing agent. This can be solved by the following means. Desulfurization can be roughly divided into bullion and slag, but the content greatly changes in the proportion of bullion and slag, and the ratio of CaO in the slag does not change much. did. That is, the CaO content can be estimated as a result if the ratio of the bullion and slag in the regenerated desulfurizing agent is known. Furthermore, the specific gravity of the bullion is as large as about 7, whereas the specific gravity of the slag is only about 2-3.

From this, it can be seen that the bulk density changes in proportion to the metal content. Using this, it is easy to cut out a certain volume of regenerated desulfurization agent immediately before use and measure its mass, and it is also easy to reflect it in the input amount. By utilizing this, the present invention can easily and quickly estimate the CaO content in the regenerated desulfurizing agent with high accuracy and obtain the regenerated desulfurizing agent amount necessary for desulfurization.

Even when the desulfurization agent obtained from desulfurization soot is used, even if the regenerated desulfurization agent component fluctuates, it is known that a stable desulfurization rate can be obtained by adding together pure CaO. Therefore, when the pure CaO content in the regenerative desulfurization agent is low, the amount added may increase, and adverse effects such as deterioration of the hot metal temperature and increase in the amount of discharged slag occur.

Therefore, by using a desulfurization agent in which any one of lime (CaO), raw stone (calcium carbonate CaCO ₃ ) and slaked lime (calcium hydroxide Ca (OH) ₂ ), or a mixture of two or more kinds is used as the regenerative desulfurization agent. The amount can be reduced. In the case of adding calcium carbonate (CaCO ₃ ) and calcium hydroxide (Ca (OH) ₂ ), a fine flux is generated in the hot metal by the following decomposition reaction, and the reaction interfacial area is increased, thereby increasing the desulfurization reaction rate. improves. On the other hand, these decomposition reactions are endothermic reactions, and oxides that inhibit the desulfurization reaction, which is a reduction reaction, are generated. Therefore, when added in a large amount, the hot metal temperature may be lowered or the desulfurization reaction may be inhibited. The addition amount needs to be 40% by mass or less.

Further, regarding the addition of the calcium carbonate component, it may be in a state where the calcium carbonate component remains in the lime by adjusting the degree of firing when the lime is fired. Also in this case, mixing is performed so that the total amount of calcium carbonate in the desulfurizing agent is 40% by mass or less. When two or more types are mixed, the total addition amount of the calcium carbonate component, limestone and slaked lime in the lime may be mixed so as to be 40% by mass or less of the entire desulfurization agent. There is no limitation on the amount of lime added, and the amount added can be freely adjusted according to the temperature of the hot metal to be treated, the amount of desulfurization required, the treatment time, and the like.

Furthermore, when adding these, a predetermined amount may be mixed and added beforehand, and the same effect will be acquired even if each is added separately to hot metal. In particular, when increasing the amount of desulfurization in a short time, addition of CaO or the like is more effective when the hot metal temperature to be treated is low.

Further, by adding a C source to the regenerated desulfurizing agent, the desulfurizing ability of the regenerated desulfurizing agent can be further improved.

In the case of addition of C source, C source acts as a reducing agent and desulfurization proceeds in the hot metal by the following reaction, thereby improving the efficiency of desulfurization reaction.

CaO + S + C → CaS + CO (1)
Moreover, a part of C source can melt | dissolve in a hot metal, and the heat source for the temperature rising by the decarburization in a converter can be increased. If it is added in a large amount, an excessive C source exceeding the above-described reduction reaction and the amount dissolved in the hot metal remains, and the increase in the amount of slag may adversely affect the operation and environmental problems. Therefore, it is preferable to mix the C source in the desulfurizing agent so that the amount added is 30% by mass or less. Moreover, since the sulfur component is contained depending on the C source to be used, depending on the amount added, there is a risk of increasing the S concentration in the hot metal. In particular, since the amount dissolved in the hot metal changes depending on the hot metal temperature, it is added depending on the type of C source to be used, the temperature of the hot metal to be processed, the S concentration in the hot metal, and the required desulfurization amount and processing time. It is possible to adjust the amount. The C source to be added is not particularly limited, and any of C sources such as coal, coke, pitch coke, and plastic may be used.

Furthermore, when adding this, a predetermined amount may be mixed with the regenerated desulfurizing agent in advance, or the same effect can be obtained even if each is added separately to the hot metal. The C source can be added in the form of a lump, granule or powder, but in order to facilitate dissolution in the hot metal, a powder form of about 1 mm or less is preferred.

(Method of desulfurizing hot metal)
The desulfurization agent containing the regenerated desulfurization agent obtained as described above and the lime source and / or carbon source added as necessary is applied to the hot metal desulfurization process. The regenerated desulfurization agent can be applied without depending on the equipment configuration and method of the hot metal desulfurization method.

The desulfurization equipment using the regenerative desulfurization agent can be any of mechanical stirring type (KR method), injection method (topy), and converter type. As the chemical component of the main hot metal, [mass% C] = 3.5 to 5.0, [mass% Si] = 0 to 0.3, [mass% S] = 0.02 to 0.05, [mass % P] = 0.1 to 0.15, and the temperature is in the range of 1250 to 1450 ° C. In the treatment, 5 to 300 ton of hot metal is charged into a smelting vessel. The desulfurization agent can be mixed with the regenerated desulfurization agent and the lime in advance, or can be cut out and added from separate hoppers. However, in order to ensure the freedom of operation, it has a plurality of hoppers. It is effective. In any refining vessel, any method can be used as long as it is effectively supplied to the bath surface, and the input amount is changed according to the Si, S, P concentration in the molten iron, and the range is 20 kg / t at the maximum. Is desirable.

Next, examples of the present invention will be described.

Example 1 (Example in which the desulfurized soot generated in the hot metal pretreatment in the KR method is reused as a desulfurizing agent in the hot metal desulfurizing process by the same KR method)
In this embodiment, the desulfurization soot generated in the desulfurization process by the KR method is actively cooled and crushed by an optimum treatment method, and then reused as a desulfurization agent again in the desulfurization process by the KR method. In the regeneration treatment, mechanical pulverization / cooling / sprinkling treatment was appropriately combined. Specifically, the regeneration treatment was performed by the following method.

The desulfurized soot generated in the hot metal pretreatment in the KR method is first mechanically pulverized during hot soaking. Specifically, this pulverization can be performed by using a heavy machine such as an excavator. Furthermore, it is possible to promote cooling and collapse by performing watering treatment on the hot water. Specifically, watering equipment was used for cooling.

Moreover, it may leave without performing watering and may cool. In this case, in order to promote cooling, the desulfurization soot is spread as thin as possible and the contact area with the atmosphere is increased to promote cooling and further to react with water vapor and carbon dioxide in the air. By accelerating, it is preferable to promote the disintegration of lime and the generation of compounds such as calcium carbonate and calcium hydroxide. Furthermore, after pulverizing the hot metal, it is possible to pass through a sieve and separate large lumps such as metal in advance.

Reactive desulfurization agent particles having a maximum particle size of 30 mm or less were obtained by proceeding cooling and crushing of the desulfurization soot by positively treating the desulfurization soot produced by such a method. If necessary, this may be further mechanically pulverized.

Since the maximum particle size of the obtained regenerated desulfurizing agent is 30 mm or less, it is possible to secure a sufficient surface area to participate in the desulfurization reaction, and since it is not finer than necessary, dust during processing can be prevented. At the same time, at the time of reuse by the KR method, it is possible to improve yield reduction and entrainment deterioration due to scattering.

In addition, by actively cooling and collapsing as described above, it is possible to promote the formation of compounds such as calcium carbonate and calcium hydroxide. These compounds are expected to improve desulfurization efficiency by promoting the stirring of hot metal by decomposition accompanied by dehydration and degassing reaction when added to the hot metal, and by increasing the reaction interface area by decomposition.

By the above regeneration method, a desulfurization agent having a new interface having a desulfurization capacity and a particle size of 30 mm or less can be efficiently obtained, and this was used as a desulfurization agent in Examples.

For comparison, a desulfurizing agent containing 90% of lime and 5% of meteorite used in the past was used. Table 1 shows the average compositions of the comparative desulfurizing agent of the comparative example and the regenerant of the present example.

This desulfurizing agent was applied to a mechanical stirring desulfurization apparatus under the conditions shown in Table 2 to perform hot metal preliminary desulfurization treatment.

The desulfurization rate after hot metal desulfurization with a mechanical stirring desulfurization apparatus was examined for each desulfurization agent, and the relationship between the additive basic unit (flux basic unit) and the desulfurization rate is shown in FIG. In the graph of FIG. 3, curve a is the result for the regenerated desulfurizing agent of the present invention, and curve b is the result for the conventional desulfurizing agent of the comparative example.

From the graph of FIG. 3, it can be seen that when the desulfurizing agent basic unit is equal, the regenerated desulfurizing agent exhibits a desulfurization rate of about 50 to 90% of the comparative desulfurizing agent. Furthermore, the graph of FIG. 4 shows a comparison between the lime content units. From this graph, it can be said that the regenerated desulfurizing agent has almost the same desulfurizing ability as the comparative desulfurizing agent when compared with the lime content. Therefore, in the treatment using the regenerated desulfurizing agent, if the lime content unit in the regenerated desulfurizing agent is estimated to be equivalent to the amount of lime required for the desulfurization reaction, the desulfurization effect is comparable to that of the desulfurization treatment using lime. It can be expected.

Table 3 shows changes in the amount of lime used before and after the introduction of this process. By reusing the desulfurized soot, the amount of lime used has definitely decreased, and the processing cost has been reduced by about 40% compared to before the introduction.

Table 4 shows changes in slag generation before and after the introduction of this process. The amount of slag generated has been reduced by 4000 t / month, and this proved to be a process that not only reduces the desulfurization cost but also solves environmental problems by reducing the amount of slag.

According to this embodiment, the desulfurization cost can be reduced and the desulfurization slag can be reused. In addition, the slag amount can be reduced and the environmental problem can be solved. Is big.

Example 2 (Example regarding desulfurization rate of reused desulfurized soot and number of times of reuse of desulfurized soot)
In this example, desulfurized soot generated in the desulfurization step was cooled and crushed by cooling or sprinkling, and then reused as a desulfurization agent in the same process. In this example, a regenerated desulfurization agent having a particle size of 100 mm or less and 200 ° C. or less can be obtained without mechanical pulverization, and this was used as a desulfurization agent in Examples. Further, after performing desulfurization using a regenerated desulfurizing agent, the slag was recovered again, and the temperature was set to 100 mm or less and the temperature was set to 200 ° C. or less by the above method, and the desulfurizing agent was used again.

For comparison, a desulfurizing agent containing 90% of lime and 5% of meteorite used in the past was used. The average composition of the regenerated desulfurizing agent and the conventional desulfurizing agent used is shown in Table 1 (each table is summarized at the end of the specification).

This desulfurizing agent was applied to a mechanical stirring desulfurization apparatus under the conditions shown in Table 2 to perform hot metal preliminary desulfurization treatment.

FIG. 1 is a diagram showing the relationship between lime intensity and desulfurization rate at each level. From this figure, it is understood that when the lime basic units are equal, the regenerated desulfurization agent used for the first time in FIG. 1 and the regenerated desulfurization agent used for the second time have a desulfurization capacity of 80% or more of the comparative desulfurization agent. Therefore, even in the treatment using the regenerated desulfurization agent used for the second time, if the lime basic unit to be added is appropriately increased, a desulfurization effect similar to that of the desulfurization treatment using lime can be expected.

FIG. 2 shows changes in the amount of desulfurization agent used before and after the introduction of this process, and the number of times the desulfurization agent is recycled and the change in the amount of used desulfurization agent. The amount of recycled desulfurizing agent used has been greatly reduced by recycling the desulfurizing agent many times, and if it is recycled about three times, the amount of desulfurizing agent used has been reduced by about 75% compared to before the introduction. The amount of slag generated at the same time is greatly reduced, and it has been proved that this process is effective for environmental problems.

Thus, from this example, by using the desulfurization agent of the present invention, the desulfurization cost can be reduced, the desulfurization soot can be reused many times, the amount of waste is reduced, and the environmental problem is solved. There is a great effect.

Example 3 (cooling and crushing by watering treatment)
In this embodiment, the desulfurized soot generated in the desulfurization step is simultaneously cooled and crushed by watering treatment, and then reused as a desulfurization agent by performing a drying treatment. Specifically, watering is performed excessively until the slag is completely hydrated by using watering equipment for the hot water after the desulfurization treatment. Thereafter, the water-containing slag was completely dried using a drying apparatus, thereby obtaining a sufficiently finely divided desulfurization agent having a particle size of about 5 mm or less. The apparatus used for this drying may specifically be a dryer, or may be dried on a large scale using an apparatus such as a rotary kiln. Depending on the required amount of processing, the size of the apparatus, etc. As long as it can be set and the water content in the slag after cooling can be sufficiently removed, any apparatus or method can be used.

The regenerated desulfurizing agent thus regenerated was used as the desulfurizing agent in the examples.

For comparison, a desulfurizing agent containing 90% of lime and 5% of meteorite used in the past was used. Table 5 shows the average composition of the regenerated desulfurizing agent and the conventional desulfurizing agent used.

The regenerated desulfurizing agent was applied to a mechanically stirred desulfurization apparatus under the conditions shown in Table 2 to perform hot metal preliminary desulfurization treatment.

FIG. 5 is a diagram showing the relationship between the lime basic unit and the desulfurization rate at each level. From this figure, it is understood that when the lime basic units are equal, the regenerated desulfurizing agent (shown by a solid line) has a desulfurizing ability of about 70% of the comparative desulfurizing agent (shown by a broken line).

Example 4 (cooling and crushing by watering treatment)
In this embodiment, the desulfurization soot generated in the desulfurization process is simultaneously cooled and crushed by watering treatment and then reused as a desulfurization agent. That is, using a watering facility for the hot water after the desulfurization treatment, stirring is performed by a heavy machine such as a shovel while uniformly spraying water. Specifically, by spraying water until the hot water is cooled to a temperature of about 150 ° C. to 80 ° C., and then cooling to room temperature, a sufficiently finely divided desulfurization agent having a particle size of about 5 mm or less is obtained. Obtained. The cooling target temperature is not limited to a certain temperature, and the cooling target temperature can be set according to the required processing amount. This was used as an example desulfurization agent.

For comparison, a desulfurizing agent containing 90% of lime and 5% of meteorite used in the past was used. Table 7 shows the average composition of the regenerated desulfurizing agent and the conventional desulfurizing agent used.

This desulfurization agent was applied to a mechanically stirring desulfurization apparatus under the conditions shown in Table 2 to perform a hot metal preliminary desulfurization treatment.

FIG. 9 is a diagram showing the relationship between the lime basic unit and the desulfurization rate at each level. From this figure, it is understood that when the lime basic unit is equal, the regenerated desulfurizing agent regenerated by watering up to 150 ° C. has almost the same desulfurizing ability as the comparative desulfurizing agent.

However, even in a regenerated desulfurization agent that has been subjected to the same watering treatment, there is a difference in desulfurization capacity when watering is stopped up to 100 ° C. and when watering is performed below 100 ° C. This is because, as shown in FIG. 7, the amount of calcium hydroxide generated in the regenerated desulfurizing agent is remarkably increased when cooled to 100 ° C. or less, and this generation amount is excessively increased, thereby adversely affecting desulfurization. It is thought that it is exerting.

FIG. 6 shows the relationship between the sprinkling end temperature and the time required to cool the 40T desulfurization soot to room temperature. The higher the temperature is, the more time is required for cooling to room temperature.

By using the desulfurization soot treatment method of this embodiment, the desulfurization soot can be efficiently treated, the time and cost required for regeneration of the desulfurization soot can be reduced, and a large amount of desulfurization soot can be reused. Therefore, there is a remarkable effect that the amount of slag is drastically reduced and the environmental problem is solved.

Example 5 (cooling and crushing by cooling)
In this embodiment, the desulfurization soot generated in the desulfurization step is allowed to cool and then simultaneously cooled and crushed and then reused as a desulfurization agent. Specifically, the hot water after the desulfurization treatment is left in a state where the contact area with air is as large as possible, and stirring is performed with a heavy machine such as a shovel. Specifically, the regenerative desulfurization agent sufficiently refined to 200 ° C. or less in 3 days by spreading the hot metal to a thickness of 0.5 m or less and performing stirring about 1 to 3 times a day. Could get. The thickness at the time of cooling is not limited to this thickness, and the target thickness can be set according to the required processing time and amount, the area of a place where it can be used for the regeneration process, and the like. Further, the agitation is performed to improve the cooling rate, and the frequency can be changed depending on the required processing time and amount, and may be omitted when there is a margin in the processing time and amount. . This was used as an example desulfurization agent.

Furthermore, a regenerated desulfurizing agent can be obtained in the same manner even when the desulfurized soot is left without being reduced in thickness. This is also shown as an example desulfurization agent.

Further, as a comparison with respect to the cooling method, a desulfurized soot (mechanical pulverizing agent) that was mechanically pulverized was used.

Furthermore, as a comparison of the desulfurization behavior, a desulfurization agent containing 90% of lime and 5% of meteorite, which were conventionally used, was used. Table 8 shows the average compositions of the regenerated desulfurizing agent and the conventional desulfurizing agent used.

This desulfurization agent was applied to a mechanically stirring desulfurization apparatus under the conditions shown in Table 2 to perform a hot metal preliminary desulfurization treatment.

FIG. 10 is a diagram showing the relationship between the lime basic unit and the desulfurization rate at each level. From this figure, it can be seen that when the lime basic units are equal, the regenerated desulfurizing agent regenerated by cooling has almost the same desulfurizing ability as the comparative desulfurizing agent.

In addition, even in the same non-sprinkling treatment, it can be seen that the machine pulverization has a lower desulfurization capacity than the regenerated desulfurization agent that has been allowed to cool. Unlike the mechanically pulverized regenerated desulfurizing agent, several percent of calcium carbonate is generated in the regenerated desulfurizing agent that has been treated by cooling, as shown in Table 8. This is considered to be because the decomposition of the calcium carbonate promotes the stirring of the hot metal, and the desulfurization efficiency is improved by the increase of the reaction interface area due to the decomposition.

A comparison between the desulfurization capacity of the regenerated desulfurizing agent and the time required for the regenerating process due to the difference in the desulfurizing method for desulfurizing soot shown in Examples 3 to 5 is shown below.

Even when the same regenerative desulfurizing agent is used, it can be seen that although it is pulverized by watering (150 ° C. watering, watering), it has higher desulfurization ability than mechanically pulverized. This is because several percent of calcium carbonate is formed in the regenerated desulfurizing agent pulverized by watering, and the decomposition of the calcium carbonate promotes the stirring of the hot metal during the desulfurization treatment, and the reaction interfacial area is increased by the decomposition. This is probably because desulfurization efficiency was improved.

However, there is a difference in desulfurization capacity between the case where the water spraying is controlled (150 ° C. watering) and the water content (watering) is performed even in the regenerated desulfurization agent that has been subjected to the same watering treatment. This is because, as shown in FIG. 7, the amount of calcium hydroxide (Ca (OH) ₂ ) generated in the regenerated desulfurized soot is remarkably increased when cooled to 100 ° C. or less, and this generated amount increases. It is thought that it is having a bad influence on desulfurization by doing too much.

Table 6 compares the treatment conditions of the desulfurization soot and the time required to regenerate the desulfurization soot by about 40T. From this table, it can be seen that the desulfurized soot treated with water spray is cooled very quickly compared with the desulfurized soot left unsprinkled. Further, in the case of treatment by watering, pulverization is simultaneously completed within the time required for this cooling. Furthermore, when the amount of sprinkling is controlled, the drying treatment after the sprinkling treatment is unnecessary, and the equipment, cost and time required for pulverization and drying can be saved. In addition, by sprinkling water during the treatment, dust generation from the desulfurization soot during the treatment can be prevented.

On the other hand, in the treatment by non-watering cooling, when the desulfurization thickness is 1.5 m, the treatment time is 170 hours, whereas when the thickness is 0.4 m, the treatment time is 70 hours. The time has decreased significantly. In addition, the relationship between the processing time and the temperature in the thickness during each processing is shown in FIG. 8 (the solid line is 0.4 m thick and the broken line is 1.5 m thick). As the thickness is reduced, the processing speed can be improved. However, the thickness can be determined by a required cooling rate, a usable cooling area, and the like. In the non-watering treatment method according to the present invention, a treatment time is slightly required as compared to the watering treatment, but no watering equipment is required. In addition, in sprinkling treatment, it is difficult to perform uniform sprinkling at the time of mass treatment, so that water-containing slag may be generated, and it is difficult to control so as not to generate this. Hydrous slag has problems such as difficulty in handling after the regeneration treatment, generation of a flame at the time of charging, and poor desulfurization capability. On the other hand, in the non-sprinkling water cooling treatment method, uniform treatment is easy even in the case of a large amount of treatment, and the lime content in the slag is “blown” during cooling (that is, a part of the lime content in the slag). However, it reacts with moisture and carbon dioxide in the air during cooling, and changes in volume, resulting in pulverization). As the slag particle size decreases with time, mechanical pulverization after cooling treatment Is not required at all. Furthermore, a part of the lime content in the slag reacts with carbon dioxide in the air during the cooling to generate calcium carbonate that is effective in improving the desulfurization reaction efficiency.

As described above, depending on the conditions of the amount of desulfurization soot to be regenerated and the equipment owned, etc., the desulfurization soot treatment method of the embodiment can be effectively used to perform an inexpensive and efficient desulfurization soot treatment, The time and cost required to regenerate the desulfurized soot can be reduced, and a large amount of desulfurized soot can be reused, so that the amount of slag is drastically reduced and the environmental problem can be solved.

Example 6 (Sieving of desulfurized soot after separation of bullion)
In this example, the desulfurized soot generated in the desulfurization process is screened with a sieving device 12 having a mesh size of 70 mm while keeping the hot soot at 900 to 1200 ° C., and a small-diameter desulfurized soot containing a large amount of unreacted lime. First, separate into large diameter bullion. As long as the sieve can be used in a temperature range of 900 to 1200 ° C., an iron-made one is sufficient without any problem. If this sieve can be used in the desulfurization treatment plant, there are no restrictions on the shape and specifications. The sieve mesh is restricted by the supply device on the desulfurization equipment side when used as a desulfurization agent, and there is no problem if an appropriate one is used.

The small-sized desulfurized soot screened after cooling is transported to a supply device on the desulfurization facility and used as a regenerated desulfurizing agent.

On the other hand, the remaining bullion can be easily recovered by using the above method, and can be reused as an iron source in the hot metal pretreatment process, which can greatly contribute to the improvement of the iron yield. There is also.

In this example, the desulfurization soot was regenerated under the conditions shown in Table 9. The sieve was installed with an angle with respect to the horizontal plane, and the hot cake was dropped from above to screen the sieve. Table 10 shows the desulfurization agent mass balance during the regeneration process. Even if sieving is performed on the desulfurized soot produced by the desulfurization treatment, it is confirmed that about 90% of CaO is recovered in the desulfurized soot, and the metal is effectively removed. That is, by using the method according to the present invention, it has been proved that the slag content in the desulfurization soot can be effectively recovered without performing magnetic separation.

The regeneration desulfurization agent and lime were applied to the desulfurization treatment to investigate the desulfurization behavior. As for some levels, the regenerative desulfurization agent and lime were mixed in both cases where they were mixed in advance and charged into the hopper and cut out, and when both were cut out from the two hoppers. Table 17 also shows the average composition of lime-based desulfurization agents as conventional desulfurization agents. These desulfurizing agents were applied to a mechanical stirring desulfurization apparatus under the test conditions shown in Table 11 to perform hot metal desulfurization.

FIG. 16 shows the relationship between the lime basic unit and the desulfurization rate. Since the equivalent concentration of lime in the regenerated desulfurizing agent is smaller than that of the comparative example, the desulfurizing agent input amount is increased accordingly, but the desulfurizing ability is equivalent to that of the comparative example, and the effectiveness of the present invention was proved.

Next, in order to examine the influence of the desulfurization soot temperature on the dust generation, it was left in the range of 30 minutes to 4 hours after the hot soot generation, and the dust generation state and temperature change were examined through the sieving device 12 described above. Table 14 shows the state of dust generation when the temperature is changed and sieved. It was found that the dust generation state changed greatly at 600 ° C. as the pre-sieving temperature. Using this, it is possible to perform operations such as sieving without a dust collector. Table 15 shows the results of measuring the temperature drop during the sieving operation. The temperature drop during sieving is about 100 ° C., and the time required for cooling can be shortened accordingly. Table 16 shows the dust generation situation in the sieving equipment according to the present invention and the sieving equipment without the swash plate (14) and slide (16) in FIG.

According to the sieving of the present invention, a sieving treatment can be performed without a dust collector even with a desulfurization slag that easily generates dust at 600 ° C. or less. By using the method of this embodiment, the dry desulfurization soot sizing equipment for recycling the desulfurization soot can be greatly simplified, and dust generation during sieving can be handled with simple equipment. Moreover, it leads to cooling promotion by efficiently contacting with the outside air during sieving. Furthermore, loading can be performed while suppressing dust generation without using a dust collector by loading the dump by the loading method described in the present invention.

By performing the treatment of this embodiment, it is possible to treat the desulfurization agent at a low cost and efficiently, and the amount of desulfurization soot to be performed in the conventional treatment is reduced, so that a significant cost reduction is achieved. In addition, a large amount of desulfurized soot can be regenerated and reused, and the amount of slag can be reduced, resulting in a remarkable effect that leads to the solution of environmental problems.

Example 7 (Handling of regenerated desulfurizing agent)
When the dried desulfurizing agent that has been subjected to the regeneration treatment is loaded into a transport vehicle such as a dump truck for reuse, it is naturally pulverized and it is very easy to generate dust. However, the generation of dust can be reduced to the maximum by using a car that has suction capability without using a truck for transporting this regenerated desulfurizing agent. At the same time, if a sieve is used at the time of suction, regeneration is simultaneously performed. The sieving of the agent becomes possible, and handling and transportation with low dust generation and high efficiency become possible.

Specifically, a suction hose is connected to a car having suction capability for the regenerated desulfurization agent after cooling and pulverizing the desulfurization soot generated in the hot metal desulfurization step, and loading is performed by suction. At this time, if a jig having a sieve mesh for sieving is used at the suction port, sieving to a required particle size is possible at the same time. Here, the jig to be attached to the suction port at the time of suction can be selectively used depending on the required degree of sieving, that is, the required granularity of the regenerated waste.

Furthermore, when sieving is not necessary at the time of suction, it is possible that suction is not required at the suction port, and suction is performed only with a hose.

Furthermore, when it is necessary to remove only a large mass of several tens of centimeters, a simple jig in which the tip of the jig as shown in FIG. The regenerated desulfurizing agent was loaded by suction and sifted simultaneously. In this example, desulfurization soot generated in the mechanical stirring desulfurization process was used. This was left to cool in the building for about 6 days, and was stirred about 3 times / day in order to speed up the cooling.

This time, the diameter of the hose used for suction was 15 cm, and as the jig 11 attached to the suction port during suction, two types of 30 mm and 5 mm meshes and a conical jig were used. These jigs all have an air suction port. Furthermore, the example which sucked only with the hose without using the jig was also performed as a comparative example. Table 12 shows the specifications of the suction wheel used.

Table 13 shows the processing amount and suction capacity when the regenerated desulfurizing agent is sucked using the various suction mouth types described above. From these results, it is understood that 1 t / min. It can be said that efficient loading of a certain degree is possible. In addition, a temperature drop of about 30 ° C. has been confirmed before and after the treatment due to the positive contact between the regenerated desulfurizing agent and the outside air during suction.

In addition, most of the sieved lumps and slag on the sieve are bullion, which can be used separately.

With the handling method of the present invention, it was confirmed that even with a regenerated desulfurization agent that is easily pulverized and finely pulverized, the sieving process and the loading operation into the transport vehicle can be efficiently performed simultaneously without a dust collector.

In this embodiment, in the desulfurization agent processing method for desulfurization soot recycling, it is possible to load while controlling dust generation to the maximum without using a dust collector by using a transport vehicle having suction capability. Furthermore, by simultaneously sieving during suction, the regenerated desulfurization agent can be treated efficiently. In addition, there is an effect that the cooling can be promoted by sieving and efficiently contacting with the outside air or suction air during suction.

Example 8 (Measurement of CaO content in desulfurized soot)
In this example, desulfurization soot generated in the mechanical stirring desulfurization process was used. This was passed through a sieving device consisting of a wire mesh of 70 mm square.

The result of reusing this sized regenerated desulfurizing agent in a mechanically stirred desulfurization facility is shown. FIG. 14 shows the relationship between the pure CaO content and the desulfurization amount ΔS (pretreatment sulfur amount (S) −posttreatment sulfur amount (S)). It was found that a clear correlation was obtained between the amount of desulfurization by arranging the pure CaO content. By utilizing this, the desulfurization agent input amount can be easily determined for each pre-treatment sulfur amount (S), and a stable desulfurization rate can be obtained.

FIG. 15 shows the relationship between the bulk density and CaO mass%. It can be seen that the bulk density decreases with increasing CaO. By utilizing this, it is possible to estimate the CaO mass% in the regenerated desulfurizing agent by measuring the bulk density.

When twisted in this example, when the desulfurized soot was reused in a mechanically stirred desulfurization facility, the amount of desulfurizing agent required was determined simply and quickly, and a stable desulfurization rate could be obtained.

Example 9 (Example regarding improvement of desulfurization efficiency by addition of lime source (CaO, CaCO ₃ , Ca (OH) ₂ ))
One or more of the above-mentioned desulfurization agents were added to a desulfurization agent (denoted as a regenerated desulfurization agent) obtained by cooling and pulverizing the desulfurization soot generated in the desulfurization process by cooling or sprinkling, and used as a desulfurization agent in the examples. As a comparison, the case where only the regenerated desulfurizing agent was used was also carried out. Table 18 shows the amount of the regenerated desulfurizing agent added, the type and amount of the desulfurizing agent.

These desulfurization agents were applied to a mechanical stirring desulfurization apparatus under the conditions shown in Table 19, and a hot metal preliminary desulfurization treatment was performed.

FIG. 19 is a diagram showing the relationship between the lime content unit and the desulfurization rate at each level. From this figure, when the lime content unit is equal, the desulfurization efficiency is slightly increased when (d) regenerated desulfurizing agent + lime is used, compared to (a) using only the regenerated desulfurizing agent in FIG. Furthermore, in the case of (b) regenerated desulfurizing agent + CaCO ₃ , (c) regenerated desulfurizing agent + CaCO ₃ + Ca (OH) ₂ , (e) regenerated desulfurizing agent + lime + CaCO ₃ + Ca (OH) ₂ , CaCO ₃ and Ca It can be seen that the desulfurization efficiency improves as the amount of (OH) ₂ added increases. This is thought to be because, as described above, during the desulfurization treatment, the reaction interface area increased due to the decomposition of CaCO ₃ and Ca (OH) ₂ , or stirring of the hot metal was promoted by the decomposition, and the desulfurization efficiency was improved. It is done.

The CaO ratio contained in the regenerated desulfurizing agent when the lime content in the desulfurizing agent having the composition used in the examples is 8 kg-CaO / T, the amount of the regenerated desulfurizing agent added, the type and added amount of the desulfurizing agent, the total desulfurization Table 20 shows the dosage. When the same amount of lime is required, when the regenerated desulfurizing agent is used alone, a large amount of desulfurizing agent is required when the regenerated desulfurizing agent has a small amount of pure lime. By adding a desulfurizing agent such as calcium carbonate or calcium hydroxide, it is possible to improve the desulfurization efficiency and reduce the amount of desulfurizing agent used, and also to reduce the amount of slag discharged after the treatment. Furthermore, the composition of the desulfurizing agent can be freely adjusted according to the state of the treated hot metal and the required treatment conditions, and the same effect can be obtained when these desulfurizing agents are added to the hot metal separately without mixing. It can be demonstrated.

Example 10 (Example relating to improvement of desulfurization efficiency by addition of various carbon sources)
The desulfurization agent generated in the desulfurization process was cooled and pulverized by cooling or sprinkling, and various C sources were added to the desulfurization agent used in the examples. As a comparison, the case where only the regenerated desulfurizing agent was used was also carried out. Table 21 shows the amount of the regenerated desulfurizing agent added, the type and amount of the desulfurizing agent. The C source was used as a powder of 1 mm or less.

These desulfurization agents were applied to a mechanical stirring desulfurization apparatus under the conditions shown in Table 22 to perform hot metal preliminary desulfurization treatment.

FIG. 20 is a diagram showing the relationship between the lime content unit and the desulfurization rate at each level. From this figure, when the lime content unit is the same, when using (b) to (e) regenerated desulfurizing agent + C source in comparison with (a) using only the regenerated desulfurizing agent in FIG. It can be seen that the desulfurization efficiency is improved as the amount of addition increases. Moreover, it has confirmed that an equivalent effect was acquired irrespective of the kind of C source, and the addition method. This is presumably because the C source acted as a reducing agent during the desulfurization treatment and the desulfurization efficiency was improved as described above. Moreover, a part of C source | sauce was melt | dissolving in hot metal, and in the conditions of an Example, C density | concentration in hot metal was increasing about 0.1 to 0.5% in any case.

Thus, by adding C sources, such as anthracite and coke, the desulfurization efficiency can be improved and the amount of slag discharged after the treatment can be reduced. The C source used here may be anything as long as it becomes a C source such as coal, coke, pitch coke, and plastic. Furthermore, the composition of this desulfurizing agent can be freely adjusted depending on the state of the treated hot metal and the required processing conditions, and these desulfurizing agents exhibit the same effect even when added separately to the hot metal without mixing. It is possible.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, desulfurization soot obtained by hot metal desulfurization treatment is effectively reused, thereby reducing hot metal desulfurization cost and slag generation. There is provided a method for desulfurizing hot metal that makes it possible. Moreover, according to this invention, the desulfurization agent for performing the hot metal desulfurization process which reduced the generation amount of slag at low cost is provided. By using the present invention, the desulfurization cost can be reduced, and the desulfurization slag can be reused. In addition, the slag amount is reduced, leading to the solution of environmental problems. large.

The figure showing the relationship between the basic unit and desulfurization rate of the once recycled regeneration desulfurization agent of the present invention, the twice recycled regeneration desulfurization agent, and the conventional lime content desulfurization agent as a comparison. The figure showing the relationship between the frequency | count of recycling of desulfurization soot, and the basic unit of used desulfurization agent at the time of recycle | recycling slag several times by this invention. The figure showing the relationship between this invention desulfurization agent and the desulfurization agent basic unit of a conventional desulfurization agent, and a desulfurization rate as a comparison. The figure showing the relationship between the desulfurization rate of this invention desulfurization agent and the lime basic unit of a conventional desulfurization agent as a comparison. The figure showing the relationship between the reproduction | regeneration desulfurization agent processed by the method of this invention, and the basic unit of a conventional desulfurization agent, and a desulfurization rate as a comparison. The figure showing the relationship between the slag temperature at the time of completion | finish of sprinkling at the time of processing using the desulfurization soot processing method of this invention, and the time required for cooling to normal temperature. The figure showing the relationship between the temperature at the time of the end of sprinkling, and the production amount of Ca (OH) 2 in the regenerated desulfurizing agent when the desulfurization treatment method of the present invention is used. The figure showing the relationship between the cooling time and slag temperature in each slag thickness at the time of processing using the desulfurization process method of this invention. The figure showing the relationship between the regenerated desulfurization agent processed by the method of the present invention and, as a comparison, the basic unit of the conventional desulfurization agent and the desulfurization rate. The figure which shows the relationship between the basic unit and desulfurization rate in the reproduction | regeneration desulfurization agent regenerated by this invention, and the conventional desulfurization agent as a comparative example. The figure which shows an example of the sieving jig of this invention. The figure which shows the sieving equipment in this invention. Explanatory drawing of the main part of the regenerative desulfurization agent stuffing device, 1 is an overall schematic view of a regenerative desulfurization agent stuffing apparatus. The figure which shows the relationship between the CaO pure part in a desulfurization agent, and desulfurization amount (Sulfur amount before a process (S)-Sulfur amount after a process (S)). The figure which shows the relationship between the bulk density of desulfurization soot, and CaO mass%. The figure which shows the relationship between the basic unit and desulfurization rate in the conventional desulfurization agent as a comparative example and the desulfurization agent which mixed the reproduction | regeneration desulfurization agent regenerated by this invention and lime. Explanatory drawing which shows the slag processing pattern by a real machine. The figure which shows an example of the slag processing pattern of FIG. 17A with the conventional slag processing pattern. When using the desulfurized iron obtained by the mechanically stirred hot metal desulfurization method as a desulfurizing agent for the mechanically stirred hot metal desulfurization method, and using the desulfurized iron obtained by the injection method as the desulfurizing agent for the mechanically stirred hot metal desulfurization method. The figure which shows the comparison of the ratio of the lime utilized effectively for desulfurization with respect to input lime about the case where it uses. The figure which shows the relationship between the lime basic unit and the desulfurization rate in each desulfurization level. The figure which shows the relationship between the lime basic unit and the desulfurization rate in each desulfurization level. The figure which showed the result of carrying out the line analysis of the photograph which observed the aggregate of the desulfurization soot produced by the mechanical stirring type hot metal desulfurization process by SEM, and its S element. The difference between the stirring type hot metal desulfurization iron and the hot metal desulfurization iron by the injection method is schematically shown. An example of hot metal pretreatment is shown. An example of the removal S equipment of FIG. 23 is shown.

Claims (42)

A method for producing a desulfurizing agent for hot metal, which performs a process for creating a new interface with respect to the desulfurized iron produced by the mechanical stirring type hot metal desulfurization process. The method according to claim 1, wherein the desulfurizing agent for hot metal used in the mechanically stirring hot metal treatment is a method for creating a new interface with respect to the desulfurized iron produced by the mechanically stirring hot metal desulfurization treatment. The method according to claim 1, comprising a step of preparing a desulfurization slag generated by the mechanical stirring type hot metal desulfurization treatment, and a step of performing a process of creating a new interface on the prepared desulfurization slag. The method according to claim 1, wherein the step of creating a new interface includes crushing the desulfurized soot particles and / or separating agglomerates of the plurality of desulfurized soot particles into desulfurized soot particles. The process of creating a new interface includes crushing the desulfurized soot particles and / or agglomerating a plurality of desulfurized soot particles by air-cooling the desulfurized soot and / or applying mechanical energy to the desulfurized soot. The method of claim 1, wherein the product is separated into desulfurized soot particles. 6. The method according to claim 5, wherein the cooling of the desulfurized soot is one or two selected from the group of air cooling and water cooling. The method according to claim 6, wherein the air cooling is one or two selected from the group of natural cooling and forced cooling. The process of creating a new interface by water cooling comprises a process of sprinkling water into the desulfurization tank, and this watering process is performed by controlling the amount of water sprayed so that the temperature of the desulfurization tank at the end of watering is maintained at 100 ° C or higher. The method according to claim 6, wherein the desulfurized soot condensate can be separated and / or the desulfurized soot particles can be crushed only by cooling with water spray. The method according to claim 1, wherein the step of creating a new interface includes a step of water-cooling the desulfurized soot and a step of drying the regenerated desulfurizing agent obtained by water cooling. The manufacturing method according to claim 1, wherein the process of creating a new interface includes a process of cooling the desulfurization soot and a process of adjusting the particle size of the desulfurization soot and the regenerated desulfurization agent. The manufacturing method according to claim 10, wherein the step of adjusting the particle size of the regenerated desulfurized material with a sieve is performed at a temperature of 600 ° C or higher. The process of creating a new interface is a process of magnetically removing the bullion contained in the desulfurization soot or regenerated desulfurizing agent, removing a large mass in the desulfurizing soot or regenerated desulfurizing agent, and reducing the particle size to 100 mm or less. The method according to claim 1, further comprising a step of performing one or two or more types of treatments selected from the group consisting of: a treatment for reducing the temperature of the desulfurization soot or regenerated desulfurization agent to 200 ° C. or less. The method according to claim 1, wherein the step of creating a new interface includes a step of setting the particle size of the desulfurization soot to 100 mm or less and the temperature to 200 ° C. or less. It has a step of loading the regenerated desulfurizing agent generated by the mechanical stirring type hot metal desulfurization treatment into a transport vehicle using a pair of movable cage parts that can be opened and closed, and a step of transporting the regenerated desulfurizing agent to a desulfurization treatment facility by a transport vehicle. Transport method of regenerated desulfurization agent. 15. The method according to claim 14, further comprising the step of sieving the regenerated desulfurizing agent after cooling and crushing to remove a large mass before or simultaneously with the step of transporting using a transport vehicle. A regenerative desulfurization agent comprising a step of loading a regenerated desulfurizing agent produced by a mechanical stirring type hot metal desulfurization treatment into a transport vehicle having a regenerative desulfurization agent suction capacity and a step of transporting the regenerated desulfurization agent to a desulfurization treatment facility by a transport vehicle. Transport method. The method according to claim 14, wherein the step of loading the regenerated desulfurizing agent is performed by adjusting the drop height of the regenerated desulfurizing agent to the transportation vehicle within 1.5 m. A regenerated desulfurizing agent sieve comprising an apparatus main body having a screen for sieving the crushed regenerated desulfurizing agent, and an air suction hose attached to the apparatus main body to promote suction of the regenerated desulfurizing agent into the apparatus main body. Dividing device. A member having a sieve mesh arranged obliquely, a diagonal plate arranged obliquely under this member, through which the sieve passes, and a slide through which the sieve from the diagonal plate falls and has a sieve mesh Regenerative desulfurization sieving sieve arranged so that the distance between the member and the diagonal plate, and the vertical drop height of the connecting portion between the diagonal plate and the slide is 500 mm or less, and the fall height from the slide to the ground surface is 1500 mm or less Dividing device. A hot metal desulfurization agent mainly composed of a regenerated desulfurization agent produced by a mechanical stirring type hot metal desulfurization treatment. 21. The hot metal desulfurization agent according to claim 20, which is used in a mechanical stirring hot metal desulfurization treatment, the main component of which is the regenerated desulfurization agent generated in the mechanical stirring hot metal desulfurization treatment. The desulfurization agent for hot metal according to claim 20, comprising a regenerated desulfurization agent that is generated by a mechanical stirring type hot metal desulfurization treatment and has a new interface. 21. The desulfurization agent for hot metal according to claim 20, comprising a regenerated desulfurizing agent as a main component which is generated by mechanical stirring type hot metal desulfurization treatment and from which a part or all of the condensate of the regenerated desulfurizing agent particles is separated. The hot metal desulfurization agent according to claim 20, wherein the maximum particle size is 100 mm or less. 21. The hot metal desulfurization agent according to claim 20, further comprising at least one selected from the group consisting of a lime source and a carbon source, the main component of which is the regenerated desulfurization agent produced by the mechanical stirring hot metal desulfurization treatment. One or two selected from the group consisting of a lime source and a carbon source are mixed with a regenerated desulfurizing agent produced by a mechanically stirring hot metal desulfurization treatment, and this mixture is added to the hot metal. 20. The hot metal desulfurization agent according to 20. 21. The one or two selected from the group consisting of a lime source and a carbon source and the regenerated desulfurizing agent produced by the mechanically stirring hot metal desulfurization treatment are separated and added separately to the hot metal. Desulfurization agent for hot metal as described in 1. The hot metal desulfurization agent according to claim 20, wherein the lime source is one or more selected from the group consisting of lime, calcium carbonate, and calcium hydroxide. 21. The hot metal desulfurization agent according to claim 20, wherein the total amount of calcium carbonate and calcium hydroxide in the lime source is 40% by mass or less based on the total hot metal desulfurization agent. 21. The hot metal desulfurization agent according to claim 20, wherein the carbon source is contained in an amount of 30% by mass or less based on the total hot metal desulfurization agent. The desulfurization agent for hot metal according to claim 20, wherein the carbon source is in a powder form of 1 mm or less. 21. The hot metal desulfurization agent according to claim 20, wherein the carbon source is one or more selected from the group consisting of coal, coke and pitch. A method for producing low-sulfur hot metal, wherein a hot metal desulfurization agent mainly composed of a regenerated desulfurization agent generated by a mechanical stirring hot metal desulfurization treatment is added to the hot metal to desulfurize the hot metal. A method for producing low-sulfur hot metal in which a hot metal desulfurizing agent mainly composed of a regenerated desulfurizing agent produced by a mechanical stirring hot metal desulfurization treatment is added to the hot metal and the hot metal is desulfurized by the mechanical stirring hot metal desulfurization treatment. 34. The low-sulfur hot metal according to claim 33, wherein the hot metal is desulfurized by adding a hot metal desulfurization agent mainly composed of a regenerated desulfurization agent, which is generated by a mechanical stirring type hot metal desulfurization treatment and has a new interface, to the hot metal. Manufacturing method. Claims for desulfurizing hot metal by adding to the hot metal a desulfurizing agent for hot metal that is generated by a mechanical stirring type hot metal desulfurization treatment and that contains a regenerated desulfurizing agent in which a part or all of the regenerated desulfurizing agent condensate is separated. Item 34. The method for producing low sulfur hot metal according to Item 33. 34. The method according to claim 33, wherein the molten iron is desulfurized by adding the regenerated desulfurizing agent produced by the mechanical stirring type hot metal desulfurization treatment and one or two selected from the group consisting of a lime source and a carbon source to the hot metal. A reclaimed desulfurizing agent produced by a mechanical stirring type hot metal desulfurization treatment is mixed with one or two selected from the group consisting of a lime source and a carbon source, and the mixture is added to the hot metal to desulfurize the hot metal. 34. The method according to 33. The method according to claim 33, wherein the regenerated desulfurizing agent produced by the mechanical stirring type hot metal desulfurization treatment and one or two selected from the group consisting of a lime source and a carbon source are separately added to the hot metal to desulfurize the hot metal. . The method of Claim 37 which adjusts a mixing ratio so that it may become a predetermined | prescribed CaO pure part, when adding a lime source. The step of calculating the bulk density of the regenerated desulfurizing agent produced by the mechanical stirring hot metal desulfurization treatment, the step of calculating the pure CaO content of the regenerated desulfurizing agent from the calculated bulk density, and the calculated pure CaO content of the regenerated desulfurizing agent The method according to claim 37, further comprising the step of adjusting an addition ratio of the crushed regenerated desulfurizing agent and the lime source with reference to the above. The method according to claim 37, further comprising the step of adjusting the particle size of the carbon source to 1 mm or less when the carbon source is added.

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