JP6412488B2 - Metal recycling method for KR desulfurization - Google Patents

Description

  The present invention relates to a bullion recycling method that effectively collects and recycles bullion contained in the debris discharged by KR desulfurization as an iron source.

KR desulfurization is a process of removing S in hot metal while mechanically stirring the hot metal using an impeller or the like after introducing a desulfurizing agent such as CaO into the hot metal. In this KR desulfurization, S in hot metal is removed as a removal material. However, metal iron is contained in the removal material as a ground iron, and it has recently been possible to recycle the ground iron contained in the removal material. Is needed.
As a technique for recycling the bare metal by such KR desulfurization, those shown in the following Patent Documents 1 to 4 are known.

  For example, in Patent Document 1, a metal bar generated by dephosphorization and desulfurization is placed in a hot metal transfer container, and a hot metal of a blast furnace is received, so that the metal bar is used as an iron source for recycling. The purpose is to prevent an explosion of water vapor. In Patent Document 1, dephosphorized and desulfurized metal is collected from slag piled up in a yard under the conditions of a size of 200 mm to 1500 mm and a temperature of 100 ° C. to 600 ° C., and placed in a hot metal transfer container to be molten in a blast furnace. It is configured to prevent water vapor explosion by accepting.

  Further, Patent Document 2 aims to prevent bumping troubles that occur when the converter exhaust gas dust having adhering moisture is placed in a hot metal transport container and receiving hot metal without removing the moisture in advance. First, a cold iron source having a thickness of 1 mm or less and a length of 200 mm or less is introduced into the hot metal transfer container, and then a wet converter flue gas dust is introduced thereon, and a thickness of 1 mm or less and a length thereof is added thereto. By introducing a cold iron source having a thickness of 200 mm or less and further receiving the hot metal in the hot metal transfer container, a bumping trouble at the time of receiving or after receiving is prevented.

Furthermore, Patent Document 3 prevents a steam explosion that occurs when a cold iron source (in the embodiment, placed in a yard and containing water) is placed in front of a hot metal transport container to receive hot metal in a blast furnace. The bullion placed in the yard is bullion collected during desiliconization or dephosphorization, and has a size of 150 mm or more, and the basicity of the adhering slag (CaO / SiO ₂ : By limiting the mass ratio to 2.5 or less, the moisture adhering to the metal becomes 0.1% to 1.0%, so that a steam explosion is prevented when receiving hot metal in a blast furnace. It has become.

  Furthermore, Patent Document 4 aims to reduce the metal contained in the CaO-based slag generated in the hot metal desulfurization process to hot metal as an iron source without pulverization or magnetic separation. The CaO-based slag generated in the treatment is charged in an empty converter charging pan while it is hot, and then the molten iron is received in the converter charging pan. It is configured to reduce iron.

Japanese Patent Laid-Open No. 2006-070308 JP 2009-079256 A JP 2006-0571151 A JP 2008-081796 A

  By the way, patent document 1 mentioned above prevents a small steam explosion by using a metal bar with a particle size of 200 mm-1500 mm and temperature of 100 degreeC-600 degreeC. Therefore, when a small-diameter metal having a particle diameter of 200 mm or less and cooled to room temperature is placed in a hot metal transport container among metal bars having a smaller particle size and lower temperature, for example, a metal bar generated by KR desulfurization. There is a possibility that a steam explosion will occur when the blast furnace hot metal is received.

  Patent Document 2 discloses that in order to prevent bumping trouble at the time of receiving, in addition to the converter exhaust gas dust to be originally recycled, a cold iron source having a thickness of 1 mm or less and a length of 200 mm or less is placed in the hot metal transport container. It has been thrown. Therefore, there is a possibility that the heat in the hot metal transport container will be deprived more than necessary by the cold iron source that has been put in, the problem of metal adhesion due to lowering of hot metal temperature and hot metal pretreatment in the next process (dephosphorization / desulfurization) There is a possibility that the reaction efficiency will be lowered, and further that a heat raising agent is required in the converter process, leading to an increase in cost.

Further, Patent Document 3 is a bullion collected at the time of decontamination after desiliconization or dephosphorization, has a size of 150 mm or more, and a basicity (CaO / SiO ₂ : mass ratio) of adhered slag of 2.5. It is the structure which prevents a steam explosion by using what is the following. For this reason, if a small-diameter metal having a size smaller than 150 mm is used, a steam explosion may occur when hot metal is received in the hot metal container.

Patent Document 3 discloses that if the size of the bullion becomes 150 mm or more, the moisture adhering to the bullion can be reduced to 0.1% to 1.0%. Therefore, when a small-diameter metal having a diameter smaller than 150 mm, in which the water content may range from several percent to 20%, is not expected to prevent the steam explosion.
Furthermore, the method of patent document 4 prevents the steam explosion at the time of receiving by putting the removal thing containing a metal in a converter charging pan hot. If an attempt is made to throw in the molten iron containing iron as an iron source for recycling, there is a possibility that a steam explosion will occur when it is received in the converter charging pan.

In other words, the techniques of Patent Literature 1 to Patent Literature 4 use a bullion with a large diameter to which the amount of moisture is not attached so much, or use a hot bullion where moisture is vaporized and lost. Therefore, it is not possible to recycle a decontaminated product cooled to room temperature or a decontaminated product having a small particle size.
The present invention has been made in view of the above-mentioned problems, and even if it is a bullion that has been cooled to room temperature or contained in a wrought product with a small particle size, it can be reliably recovered and recycled. An object of the present invention is to provide a method for recycling bullion by KR desulfurization.

In order to solve the above-described problems, the method for recycling bullion in KR desulfurization according to the present invention employs the following technical means.
That is, according to the method for recycling bullion in KR desulfurization according to the present invention, when HR desulfurization of hot metal is continuously performed using a device that rotates the impeller and mechanically stirs the hot metal, the KR desulfurization is performed continuously. In addition to water-cooling the debris discharged by a series of charges as a recycle debris, the water-cooled recycle debris is a large particle having a particle diameter of 40 mm or more , a powder having a particle diameter of less than 15 mm , and a small diameter in between. A part of or all of the decontaminated product that has been discharged by the KR desulfurization charge that follows the above series of charges and has a temperature at which water can be vaporized is separated. The dry decontamination product and the small-sized recycling decontamination product obtained from the cycle decontamination product are mixed to obtain a mixed decontamination product, and the resulting mixed decontamination product is used for the drying. Charge of KR desulfurization to obtain debris In introducing the hot metal in the charge after Ri, a (%) weight ratio of the drying skimming thereof to said mixture skimming was elapsed drying time from start of mixing of the mixture skimming thereof b (hr ), The weight ratio a and the drying time b are used as variables, and the multiple regression equation shown by the equation (1) for estimating the moisture content x (%) of the mixed debris after drying is obtained,
An upper limit value y (kg / t) of the mixed debris to be introduced and a water content x (( %)) Was obtained from the recycling product so that the weight ratio of the drying product to the mixed product was a (%). A small-sized recycling decontamination product and the drying decontamination product are mixed to obtain a mixed decontamination product, and the mixed mixed decontamination product is allowed to stand for a drying time b (hr), and the formula (1) Substituting the weight ratio a of the dry sanitized product to the mixed sanitized product and the drying time b (hr) of the mixed sanitized product to obtain the moisture value x of the mixed sanitized product after drying. Substituting the moisture value x of the mixed decontaminated product after drying into the formula (2) to obtain the upper limit y (kg / t) of the input amount, and the mixed decontaminated product was obtained. The mixture skimming thereof to be less than Iriryou upper limit y (kg / t), characterized in that introducing the hot metal.

  According to the bullion recycling method in the KR desulfurization of the present invention, even a bullion contained in a debris cooled to room temperature or a debris with a small particle size can be reliably recovered and recycled. it can. Further, in the bullion recycling method in the KR desulfurization according to the present invention, the processing metal such as a drying furnace is not separately used, and the bullion with a small particle size can be safely reduced and recycled to hot metal. it can.

It is the figure which showed the prior preparation process of the bullion recycling method of this embodiment. It is the figure which showed the actual operation process of the bullion recycling method of this embodiment. It is a figure explaining KR desulfurization operation of an actual operation process. It is a figure explaining post removal operation of an actual operation process. It is a figure explaining cooling operation of an actual operation process. It is a figure explaining classification operation of an actual operation process. It is a figure explaining operation which takes out the removal thing for drying from a removal thing in an actual operation process. It is a figure explaining the mixing operation which mixes the removal thing for drying, and the removal thing for recycling in an actual operation process. In an actual operation process, it is a figure explaining charging | throwing-in operation which throws into a hot metal with the charge after the charge which obtained the demolition thing for drying in the actual operation process. It is the figure which plotted the correspondence of a moisture calculation value and a moisture actual value. It is the figure which showed the relationship between the metal adhesion | attachment water | moisture content in which a removal thing can be thrown in without causing a steam explosion, and a metal charge input amount.

Hereinafter, an embodiment of a bullion recycling method in KR desulfurization according to the present invention will be described in detail with reference to the drawings.
The bullion recycling method of the present embodiment is performed continuously when KR desulfurization of hot metal is continuously performed using a device (KR desulfurization device 1) that rotates the impeller 2 and mechanically agitates the hot metal. with water cooling the skimming object S to be Haikasu in a series of charge in desulfurization as recycle skimming product S _R, a water-cooled the recycle skimming product S _R Daikatamari S _RB, small S _RS, flour S _RP leave separated by particle size, part or all of a series of the Haikasu followed by KR desulfurization of the charge to be made to the charge and skimming product has a water vaporizable temperature drying for skimming product S _D and then, the drying skimming object S _D, the cycle for skimming product S for recycling skimming of small diameter obtained from _R by mixing the S _RS mixture skimming object S _C, resulting mixture skimming things _{S C,} the KR desulfurization give the drying skimming product _{S D} It is intended to be introduced into the hot metal in the charge after the Yaji.

More specifically, in the method for recycling the bullion of the present embodiment, the debris S generated in the KR desulfurization treatment is cooled to room temperature (at least less than 100 ° C.), and the above-described three types of debris (large block S _RB , Small diameter _SRS , powder _SRP ). These three types of skimming was skimming product S _RP of "powder" of less than 15mm skimming product S _RB and particle diameter of the particle diameter is more than 40mm "Daikatamari" is a recyclable conventionally was, but the particle size is skimming product S _RS of "small-diameter" of 15mm~40mm is, there is a risk of it when you put in the hot metal vapor explosion, recycling of bullion that is included in the skimming products has not been carried out. Therefore, the bullion recycling method of the present embodiment converts the part of the debris S to be removed by KR desulfurization into a “small-diameter” debris S _RS as a dry decontamination _SD while remaining hot. mixing, using a high-temperature drying skimming product S _D by removing dried moisture skimming product S _RS of "small", while reliably preventing the phreatic skimming of "small" so that can be recycled bullion that is included in the S _RS.

Specifically, in the bullion recycling method of the present embodiment, the “preliminary preparation process” shown in FIG. 1 is first performed, and then the “actual operation process” shown in FIG. 2 is performed.
"Preparation process" is the amount of water to estimate the water content of the mixture skimming was dried from a dry condition S _{C (the} drying skimming product S _D a mixture of skimming product S _RS of "small") and estimating equation, and a charged quantity calculation equation that defines the input amount upper limit value y mixtures skimming was S _C corresponding to the water content value is a step to be prepared in advance.

In the “actual operation process”, in actual operation, the moisture condition is applied to the moisture amount estimation formula to estimate the moisture value, and the calculated moisture estimated value is substituted into the input amount calculation formula to obtain the input amount upper limit value y. , it is assumed that input amount of skimming product obtained turns on the mixture skimming was S _c to the hot metal KR desulfurization treatment prior to hot metal pot 3 of the "small" to be equal to or less than the weight-on amount upper limit value y ing.
Hereinafter, the “preliminary preparation process” and the “actual operation process” that constitute the bullion recycling method of the present embodiment will be described.

As described above, in the technique of the present invention, after performing the “preliminary preparation process”, the “actual operation process” is performed using the obtained regression equation. However, in this specification, in order to facilitate understanding of the technology, first, the contents of the “actual operation process” will be described in detail, and then the contents of the “preparation process” will be described.
The “debris S” referred to hereinafter refers to a combination of both the slag removed in the KR desulfurization process and the metal contained in the slag.

First, the “actual operation process” will be described with reference to FIG.
The “actual operation process” of the present embodiment is an actual operation of the bullion recycling method in the KR desulfurization according to the present invention, and the following operations (1) to (6) are performed in order. ing.
(1) continuously a series of charge in Haikasu is the skimming product S for recycling dividing the slag material S _R and to be operated in the KR desulfurizing performed (KR desulfurization S1 and the rear skimming operation S2).
(2) obtained for recycling skimming product _{S R} a water cooling operation (cooling operation S3).
(3) water-cooled recycle skimming product _{S R} a Daikatamari _{S RB,} small _{S RS,} operations to be separated by particle size powdered _{S RP} (fractional operation S4).
(4) An operation of separating a part or all of the decontaminated waste that has been exhausted by the charge of KR desulfurization performed following a series of charges and that is capable of vaporizing water as a decontaminated product for drying _SD ( operation to take out the drying skimming product S _D from Jokasubutsu S).
(5) drying skimming product S _D and the cycle for skimming product S for recycling skimming of small diameter obtained from _R S _RS and mixtures skimming was a mixture of S _C and mixing operation S5.
(6) The resulting mixture skimming was S _C, drying skimming product S _D The resulting KR desulfurization charge operation to be introduced into the hot metal in the charge after the (closing operation S6).

The above processes are performed in order.
Hereinafter, each operation constituting the bullion recycling method of the present embodiment will be described.
As shown in FIG. 2, in the KR desulfurization operation, KR desulfurization of hot metal using the hot metal ladle 3 is continuously performed over a plurality of charges.
With KR desulfurization, the hot metal in the hot metal ladle 3 to which the desulfurizing agent is added is stirred using a mechanical stirring means, the desulfurizing agent is reacted with sulfur in the hot metal, and the sulfur in the hot metal is transferred to slag. Finally, the slag containing sulfur is discharged as the removal material S.

  Specifically, as shown in FIG. 3, this KR desulfurization operation is performed while stirring the hot metal in the hot metal ladle 3 using a mechanical stirring means such as an impeller 2 made of a refractory. In the illustrated example, this mechanical stirring means is attached to a KR carriage 4 that is provided so as to be movable in the horizontal direction with respect to the hot metal ladle 3, and is attached to the hot metal ladle 3 so as to be movable up and down. In the case of KR desulfurization, the KR carriage 4 is moved to a processing position where the hot metal ladle 3 is located in the center of the KR carriage 4 in plan view, and mechanical stirring means attached to the KR carriage 4 Is soaked in the hot metal in the hot metal ladle 3.

In the KR desulfurization operation, quick lime, aluminum dross or the like is added as a desulfurizing agent to the hot metal in the hot metal ladle 3 in which the mechanical stirring means is immersed. And mechanical stirring is performed so that a desulfurization agent may be wound in the hot metal of the hot metal ladle 3 by rotating a mechanical stirring means at the rotational speed of 50 rpm-150 rpm.
In the hot metal of KR desulfurization in which such mechanical stirring is performed, a reaction in which sulfur [S] in the hot metal is changed to calcium sulfide as shown in Formula (3) proceeds.

In addition, when performing the reaction mentioned above, if blast furnace slag etc. exist, reaction efficiency may fall. In such a case, in order to remove blast furnace slag and the like from the hot metal ladle 3, pre-steaming may be performed before KR desulfurization.
The slag in which the sulfur in the hot metal is fixed as a sulfide in this way is discharged by a “post removal operation” as shown in FIG.

  In other words, when performing the post-steeling operation, first, the mechanical stirring means is pulled up from the hot metal, and the KR carriage 4 is moved in the horizontal direction to move away from the hot metal ladle 3. And, in the hot metal ladle 3 after the mechanical stirring means retreats, the slag dragger 6 is stretched out from the slag chute 5 (receiving vessel) side, and the slag dragger 6 is scraped to collect the slag of the hot water surface, The slag can be discharged into the slag chute 5.

  Specifically, the above-described slag chute 5 is attached to a slag tilting carriage 7 that can move horizontally in a direction parallel to the KR carriage 4 and can accommodate the debris S scraped from the hot metal ladle 3. It has become. The slag dragger 6 is a member that is elongated along a direction orthogonal to the moving direction of the slag tilting carriage 7, and has a key-shaped structure formed by covering the tip in the longitudinal direction with a refractory. A slag removing device provided. The slag dragger 6 is a slag tilting carriage 7 so that the key structure can be moved forward and backward toward the hot metal ladle 3 side, and further, the key structure can be turned in the horizontal direction (left and right direction). The slag floating on the hot water surface of the hot metal ladle 3 is scraped out of the hot metal ladle 3 and collected in the slag chute 5.

  The slag received by the slag chute 5 in this way is further transferred from the slag chute 5 to the slag pit (first slag pit 8). That is, as shown by the dotted line on the right side of FIG. 4, the slag chute 5 of the slag tilting cart 7 can tilt sideways, and the slag chute 5 about the axis that faces the moving direction of the slag tilting cart 7. When the slag is swung, the slag chute 5 is tilted until it rises vertically, and the slag once received by the slag chute 5 (receiving container) can be left without leaving on the slag pit.

The slag received in the slag pit (first slag pit 8) in this way (hereinafter, the slag scraped out of the hot metal ladle 3 is referred to as the removal material S) is a transport vehicle as shown in FIG. 9 (a dump in the case of the figure) is transferred using a heavy machine and is transported to the yard by the transport vehicle 9. During this transportation, the cooling operation of the slag structure S described above is performed.
In the following, the cooled skimming material S while being conveyed in the yard referred to as recycle skimming object S _R, used to distinguish them from drying skimming product S _D to be described later.

Cooling operation over water recycle skimming product S _R being transported to the yard, an operation to lower the temperature of the recycle skimming product S _R by vaporization of water. The cooling operation is performed to enable the sieving described later, the temperature cycle for skimming product S _R is until at least 100 ° C. or less, is performed preferably to be room temperature.
In this embodiment, the recycle skimming product S _R being transported to the yard is placed in the transport vehicle 9 while being accommodated in Suragupan 10 cooling operation, skimming product for recycling, as shown in Figure 5 It is performed by spraying water spray nozzle 11 with respect Suragupan 10 S _R is accommodated. Incidentally, this cooling operation, as long as it performs water cooling was applied to recycle skimming product S _R a, may be employed a scheme other than watering. Further, other cooling methods such as air cooling may be used in combination with water cooling.

As shown in FIG. 6, the cooled S _R for skimming Recycling in the cooling operation is inventory management with pile yards. Then, for recycling skimming product S _R which is pile yards in the next sorting operation is classified into three types by the particle size (particle size).
Fractionation operation, the recycle skimming product S _R stored in yards after cooling, by using a sieve machine "Daikatamari S _RB", "small S _RS", divided into three types of "Powder S _RP" It is an operation.

Here, the “large block” recycling debris S _RB is a recycling debris S _R having a particle size of 40 mm or more, that is, a mixture of bullion and slag having a particle size of 40 mm or more. Used for applications such as scrap iron sources in furnaces and placement in hot metal containers.
Also, the “powder” recycling debris S _RP is a recycling debris S _R having a particle size of less than 15 mm, that is, a mixture of bullion and slag having a particle size of less than 15 mm. Powders containing iron such as dephosphorizing agents are recycled as iron sources.

Furthermore, for recycling skimming product S _RS of "small", the upper limit of the particle size, the lower limit of the recycle skimming product S _RB of "Daikatamari", for recycling skimming product S _RP of the "Powder" a recycle skimming product S _R such that between the values, in which recycling conventionally been difficult.
The above-described separation of the “large lump S _RB ”, “small diameter S _RS ”, and “powder S _RP ” into the debris for recycling is performed according to the procedure shown in FIG. 6.

That is, first, a first sieving machine 12 having an opening of 100 mm and a second sieving machine 13 having an opening of 40 mm are prepared. Then, the slag was S _R for recycling stored in yards, first sieved in a first sieving device 12. In this case, what was sieved on the sieve with the first sieve machine 12 is recycled for skimming product S _RB of "Daikatamari". Next, a first sifter 12 for recycling skimming was sieved under sieve S _R, sieved in a second sifter 13. It is this way recycle skimming product S _RP of the second sifter 13 for recycling skimming was divided under the sieve S _R is "flour", divided on the sieve in the second sifter 13 what it was is recycled for skimming products S _RS of "small".

Incidentally, when the slag dragger 6 skimming the skimming operation after the above, since the molten metal surface near the hot metal is also scraped together with the slag together with slag, Jokasubutsu S (for recycling skimming product S _R ) Contains a lot of bullion (metallic iron). Among such bullions, the bullion contained in the debris for recycling “large block S _RB ” or “powder S _RP ” is reused as a scrap iron source or a sintering raw material. However, in the conventional method, bullion that is included in the recycling for skimming products S _RS of "small" is, re-use has been difficult.

That was fractionated into "small" (sieving was) for recycling skimming product S _RS, since sprinkling the sieving is carried out, has a number of water therein. Therefore, when turning on the fractionated recycled for skimming products S _RS to "small" as it is in the hot metal, is likely to cause a steam explosion. Similar to the recycle skimming product S _RP of "powder", it is conceivable to evaporate water by the furnace heat was placed entry to the empty converter, for recycling skimming of "small" S _RS Since the particle diameter is small, it is difficult for heat to be transmitted uniformly, there is a possibility that water cannot be removed sufficiently, and it is difficult to sufficiently reduce the possibility of steam explosion.

Therefore, in the bullion recycling method of the present embodiment, the operations of (4) to (6) described later are performed, and the “small diameter” recycling removal is performed by mixing the hot drying removal material _SD. object S water is vaporized included in _RS, with each other to reliably suppress steam explosion when charged into the hot metal as a mixed skimming thereof S _C.
Specifically, in the bullion recycling method of the present embodiment, the above-described KR desulfurization is continuously performed over a plurality of charges. Then, the skimming object S which is Haikasu in KR desulfurization of each charge, all as skimming product S _R for recycling, cooled, fractionated, obtaining a recycle skimming object S _RS of "small". Once this way reached a volume a predetermined amount of recycle skimming product S _RS of "small", that in the next charge, (4) operation, i.e., "removal for drying skimming dregs thereof S _D The operation to take out "is performed.

This operation (4) is a charge of KR desulfurization performed subsequent to a series of charges for obtaining a “small-diameter” recycling debris S _RS. A part or the whole is used as a drying product _SD . This desiccated product for drying _SD is a hot product S that maintains a high temperature immediately after being discharged, and is at least a temperature exceeding 100 ° C. so that water can be vaporized, more preferably post-removal. The removal material S which is set to a temperature of 500 ° C. or more within 2 hours from the end of the dredging is used.

In this way, the recycling for skimming products S _RS of fractionated "small" is inventory management are in a pile in the yard. At this time, in the yard being outdoors, variation in the moisture content adhering to recycle skimming product S _RS due to the influence of the weather. Therefore, when recycling the recycle skimming product S _RS of stored outdoors yard "small" is preferably measured in advance the water content using the measuring method described later.

Specifically, the above-described operation (4) is performed according to the procedure shown in FIG. In other words, two slag pits (slag pits for digging) formed on the floor surface to accommodate the removal material S are formed at the first slag pit 8 and the second slag pit 14. Then, the debris S from the slag chute 5 is first discharged into the first slag pit 8 by KR desulfurization charge performed after a series of charges. When the skimming object S which is受滓the first slug pit 8 and recycled for skimming product S _R is the受滓been skimming object S in the first slug pit 8 as it haul vehicle 9 transported to yard, when a skimming object S which is受滓the first slug pit 8 and drying skimming product S _D, a part or the whole of the skimming of the first slug pit 8, such as a wheel loader A heavy machine is used to move to the second slag pit 14 provided next to the first slag pit 8. Thus the受滓been skimming object S in the first slug pit 8 if, it is possible to set aside a drying skimming product S _D and recycle skimming product S _R if necessary.

For this way, drying skimming product S _D, which is set aside in the second slug pit 14, in a mixing operation illustrated in FIG. 8, for recycling skimming product S _RS of "small" is mixed. That is, the “small-diameter” recycling debris S _{RS that} has been sieved on the sieve by the second sieving machine 13 is returned from the yard to the second slag pit 14 by the transport vehicle 9 such as a dump truck. It is. Then, the second slug pit 14 the returned small diameter for recycling skimming product S _RS are mixed in the drying skimming product S _D by using a wheel loader, to prepare a mixed skimming thereof S _C.

Thus temporary drying for skimming was S _D to the second slug pit 14, it is possible to promote drying of the recycle skimming product S _RS of "small". Moreover, it is preferable to provide the place which provides the 2nd slag pit 14 in the factory building which does not get wet with rain.
In such a mixing operation, the hot metal mixing weight ratio a and the drying time b are obtained as actual operating conditions.

When the hot-bath mixing weight ratio a and the drying time b are obtained in this way, the obtained hot-bath mixing weight ratio a and the drying time b are determined using the moisture amount estimation formula (1 ′ ). Further, the moisture amount estimation formula (1 ′) into which the actual operation conditions are substituted is further substituted into the input amount calculation formula (2) obtained in the advance preparation step described later. Then, the input amount upper limit value y mixtures skimming was S _C can be actually calculated.

That is, in the mixing operation of actual operation process, the mixture skimming was S _C at dosages not exceeding input amount upper limit value y of the calculated mixture skimming was S _C by introducing into the molten iron, preventing the vapor explosion diameter (particle size 15Mm～40mm) it is possible to reuse the ingot contained in the recycle skimming product _{S RS} of while.
In the technology of the present invention, the “preliminary preparation process” is performed prior to the “actual operation process” described above.

Hereinafter, the contents of the “preparation step” will be described in detail with reference to FIG.
The “preliminary preparation step” of the present embodiment performs the steps (1) to (6) performed in the “actual operation step”, accumulates a number of operation data, and calculates the moisture content from the obtained operation data. (1 ') and the input amount calculation formula (2) are obtained.
In other words, the pre-preparation process is the same as the actual operation process with respect to the KR desulfurization operation, the post-cleaning operation, the cooling operation, and the separation operation. That is, cooling the recycle skimming product S _R generated in the rear skimming to ambient temperature, the recycle skimming product S _R after cooling using a first sieve machine 12 and the second sifter 13 "large Sieving into “lumps S _RB ”, “small diameter S _RS ”, and “powder S _RP ”. Then, and recycling for skimming product S _RS of "small" generated by sieving the recycle skimming product S _R, drying skimming product sent from the first slug pit 8 remains hot state _SD is mixed in the second slag pit 14.

Or water content x of the thus mixed were mixed skimming was S _C is how made, the pre-preparation step, the analysis using a number of operational data for the past, in advance as "water content estimation equation" I ask for it. In addition, by using the water amount x obtained using the water amount estimation formula, what is the upper limit value y of the amount of the mixed debris that can be charged to the hot metal is referred to as an “input amount calculation formula”. Find in advance.

Specifically, the mixing weight ratio of the mixed skimming was S _C, the weight ratio of S _C drying skimming product S _D relative to the total weight of the mixture skimming thereof other words, defined as Netsukasu mixing weight ratio a . This hot iron mixing weight ratio a is the same as the weight of the hot drying debris _SD temporarily placed in the second slag pit 14 for drying, and the hot drying debris temporarily placed for drying. and weight of S _D, is obtained by dividing the sum of the weight of the recycle skimming of small diameter which is returned to the second slug pit 14 S _RS. These weights can be measured using a load cell mounted on a wheel loader, but weighing means other than the load cell may be used.

The elapsed time from the start of mixing is defined as the drying time b. This is because the drying time b can also be a parameter for estimating the moisture of the fried product after drying.
If these heat slag weight ratio a and the drying time b is utilized, the water content x of the mixed skimming was S _C, more precisely, mixtures skimming mixture in Netsukasu mixing weight ratio a is performed S _C can estimate the amount of moisture x shown when drying is performed for the drying time b.

  That is, since the water content x of the mixed debris can be predicted to be a function of the above-described hot metal mixing weight ratio a and the drying time b, the hot water mixing weight ratio a and the drying time are expressed by the following equation (1). It can be shown as a multiple regression equation with b as an explanatory variable.

The use of such a water content estimation equation (1), it becomes possible to accurately estimate the water content x of dry mixtures skimming thereof S _C.
Incidentally, the above-mentioned water content estimation equation (1) is, it does not take into account the variations, also form a mixture skimming was S _C so that the amount of water is estimated by the water content estimation equation (1), There is a possibility that the measured value of the amount of water measured in practice will exceed the estimated value (in other words, the possibility of a steam explosion described later remains). Therefore, if the actual estimated water content, as water content estimated by the water content estimation equation the water content of the mixed skimming was S _C was measured by using a moisture meter does not exceed a water content estimation formula It is preferable to increase the variation in (1).

  That is, the difference between the moisture amount estimated by the moisture amount estimation formula (1) and the moisture amount actually measured using the moisture meter is obtained, and the difference (variation) obtained is maximized. Select as "variation c". It is preferable to use a correction formula obtained by adding the selected “maximum variation c” to the intercept of the water content estimation formula (1) as the true water content estimation formula (1 ′).

In addition, when actually measuring the moisture content x of the removed material S, any moisture meter may be used, but a moisture meter such as an infrared heating type may be preferably used. Further, the sampling position of the sample from the mixing skimming was S _C, there is a possibility that measurement results vary in water content, samples were taken to measure the water content from the plurality of positions, in the measurement results the in highest value was used the water content of the mixed skimming was S _C as a value representative.

As described above, when the water content estimation formula for estimating the water content of the mixed skimming was S _C (1 ') is obtained, introduction of hot metal allows turned mixture skimming was S _C without causing vapor explosion The amount upper limit y is obtained in advance.
This "whether water vapor explosion" is, when you put the mixture skimming compounds S _C, whether or not the scattering of flash and hot metal can be seen due to the explosion in the hot metal pot within 3, captured by the video camera, It is determined in advance.

Also, just because steam explosion does not occur, the input amount upper limit value y mixtures skimming was S _C never Fuyaseru endlessly, the input amount upper limit value y mixtures skimming was S _C exceeds a predetermined amount , undissolved mixture skimming was S _C becomes to occur, undesirably. Therefore, it does not occur such a steam explosion, followed by a range of input amount upper limit value y mixtures skimming was S _C mixture skimming was S _C that insoluble remnants are not generated as shown in Equation, dosages formula (2).

The water content x of the mixed skimming was S _C obtained by the above-described water content estimation equation (1 '), by substituting the input amount calculation formula (2), which can more reliably suppress the generation of vapor explosion mixed it is possible to obtain a calculation formula for calculating the Jokasubutsu S _C input amount upper limit value y of.
As described above, mixtures skimming was water content estimation formula for estimating the water content x of S _C (1 '), and mixtures skimming was charged quantity calculation equation for calculating the charged amount upper limit value y of S _C (2) The process for obtaining the above is the preliminary preparation process for the bullion recycling method.

Next, the effects of the metal recycling method of the present invention will be described in more detail using examples and comparative examples.
In Examples and Comparative Examples, a lime-based desulfurizing agent and an alumina-based solvent were added to a hot metal ladle 3 charged with 260 ton of hot metal, and KR desulfurization was performed for 10 minutes.
In the post removal after the KR treatment, the slag floating in the hot metal ladle 3 was performed and discharged to the slag pit (first slag pit 8) using the slag chute 5.

  The slag tilting carriage 7 at the time of the KR desulfurization process moves as indicated by an arrow in FIG. 3, the processing position shown in FIG. 3 during the KR desulfurization process, and the non-process shown in FIG. Located in position. Then, during the KR desulfurization treatment, the impeller 2 is lowered at the treatment position, and the impeller 2 is rotated about the axis to stir the hot metal. Further, the impeller 2 was raised when the KR desulfurization treatment was completed. Further, the desulfurizing agent was introduced into the hot metal ladle 3 from a hopper (not shown) on the KR carriage 4.

On the other hand, the slag tilting carriage 7 at the time of rear removal is moving as shown in FIG. That is, the slag tilting carriage 7 is moved to the non-processing position, and the slag dragger 6 is moved forward, backward, and left and right, thereby scraping the debris S (slag and metal) to the slag chute 5. Next, the slag chute 5 was tilted so that the debris S was discharged onto the first slag pit 8.
As shown in FIG. 5, the debris S discharged in the first slag pit 8 is loaded on the slag pan 10 on the transport vehicle 9 as “recycling scrap S _R ”, and the transport vehicle 9 is moved by the locomotive. Towed and transported to slag cooling area (yard). For skimming product S _R recycling transported to the slag cooling field, and then cooled to room temperature by water spray. After the sprinkling cooling, the slag pan 10 was tilted using a crane, and was discharged into the pit for digging.

As shown in Figure 6, the recycle skimming product S _R pit dug by using first sifter 12 backhoe type, the sieving was carried out at 40 mm. S _R for recycling skimming was fractionated on the sieve in the first sieve machine 12 and stored in a yard as "recycle skimming product S _RB of Daikatamari". Further, for recycling skimming was fractionated under the sieve in the first sifter 12 S _R, using the second sifter 13 of the vibrating-screen, the sieving was carried out at 15 mm. S _R for recycling skimming was fractionated under the sieve in the second sifter 13, and stored in the yard as "recycle skimming product S _RP powder."

“Large recycling debris S _RB ” was blended as a scrap iron source for the converter, and “powder recycling debris S _RP ” was blended into the sintering raw material, and iron was recovered as an iron source.
Then, moving the second sifter 13 sieve diameter for recycling skimming was fractionated on a S _RS in, the second slug pit 14 provided on the side of the first slug pit 8.
On the other hand, the skimming object S to be Haikasu a charge which is performed following the sequence of KR desulfurization is Haikasu as recycle skimming object S _R, the first slug pit 8 as the drying skimming product S _D No. 2 moves to the slag pit 14, and a drying skimming product S _D and small diameter for recycling skimming product S _RS were mixed using a wheel loader.

At this time, the weight of the small diameter for recycling skimming product S _RS and drying skimming product S _D measured by a load meter installed in a wheel loader, as a condition of Netsukasu weight ratio a, 10%, 30%, samples were produced in the mixture skimming was S _C 50% conditions.
As for the water content of the mixture skimming was S _C, from pile to the pile of "recycle skimming of small S _RS", three samples were taken by changing the sampling location, using an infrared heating type moisture meter Then, moisture was measured under the conditions of a heating temperature of 120 ° C. and a heating and holding time of 15 minutes. Of the water analysis values of the three samples, the maximum value was adopted as a representative value.

Table 1 below shows Netsukasu weight ratio a, drying time b, and the water content of the resulting mixture skimming thereof S _C.

  When a multiple regression equation with respect to the moisture value x is obtained using the hot water mixing weight ratio a and the drying time b shown in Table 1 as explanatory variables, a relational expression such as equation (4) is obtained.

When the difference between the water content x calculated by the equation (4) and the actually measured water content was calculated, the difference between the two was 3.2% at the maximum. Therefore, the following equation (4 ') is adopted as the calculation equation for estimating the water content of the mixture skimming was S _C after drying.

That is, the straight line obtained by regressing the calculated water content and the analyzed water value on a one-to-one basis in FIG. 10 is the calculation formula (1), and the straight line obtained by adding the error 3.2% to the intercept is the calculation formula (1 ').
On the other hand, 10% Netsukasu mixing weight ratio a, as described above, 30%, loading 50% 1hr drying time b, 5 hr, the mixture skimming was _{S C} which was changed -8 hr, the recycle chute 15 by the wheel loader Then, it was put on the hot metal in the hot metal ladle 3 and subjected to KR desulfurization treatment.

The movement of the recycling chute 15 at this time is as shown in FIG. 9, and the slag tilting cart 7 is moved to the recycling position, and then the recycling chute 15 is raised, turned, and tilted. the mixture skimming was S _C which has been stacked on the hot metal of the pot 3 and mass loading.
Mixing at the time of turn-on of skimming material S _C, it was observed remaining presence melting of occurrence, and mixtures skimming was S _C steam explosion inside the hot metal pot 3. The results are shown in Table 2 and FIG.

As shown in Table 2, in the case of changing the water content of the mixture skimming was S _C that is introduced into the hot metal, and a charged amount of the mixed skimming was S _C, where the vapor explosion occurs "×" , a case where the vapor explosion is not generated "○", and "×" when there are undissolved mixture skimming was S _C, melted and the case where there is no remaining and evaluation of "○". Incidentally, input amount of mixture skimming was S _C (kg / t) is a value obtained by dividing the weight of the hot metal in the hot metal in the pot was charged total input amount of the mixed Jokasu thereof. As shown in FIG. 11, the data in Table 2, mixed dividing the horizontal axis lees product moisture content of S _C, when plotted in dosages and the graph of the vertical axis mixture skimming was S _C, the vapor explosion occurs not, and undissolved mixture skimming was S _C as also shows the boundary of the region does not occur, leading to the formula (5) representing the input amount upper limit value of the mixed skimming thereof S _C.

Incidentally, steam explosion / occur no boundary, and if the water content of the mixture skimming was S _C is more than 2.5%, if the water content of the mixture skimming was S _C is 2.5% or less and it can be thought separately, when the water content of the mixture skimming object S _C is more than 2.5% (when input of mixtures skimming thereof is more than 8 kg / t), the mixture skimming object S _C becomes undissolved.
That is, the “input amount upper limit value of the mixed debris” in Table 2 described above is obtained by substituting the moisture amount (%) of the input condition into the equation (5) indicated by the thick line in FIG. ing. By introducing this way the mixture skimming was S _C so as not to exceed the charged upper limit y mixtures skimming was S _C obtained in the hot metal, without causing steam explosions, the mixture skimming was S _C insoluble remnants also so as not to occur, the applicant that is recyclable bullion contained in diameter recycle skimming product S _RS is confirmed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. In particular, in the embodiment disclosed this time, matters that are not explicitly disclosed, for example, operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component deviate from a range that a person skilled in the art normally performs. Instead, values that can be easily assumed by those skilled in the art are employed.

1 KR desulfurizer 2 Impeller 3 Hot metal pan 4 KR cart 5 Slag chute (receiving vessel)
6 slag dragger 7 slag tilting the dolly 8 first slug pit 9 transport vehicle 10 Suragupan 11 spray nozzle 12 first sifter 13 second sifter 14 second slug pit 15 divided for recycling chute S Jokasubutsu S _R Recycling introduction of slag material S _RB Daikatamari for recycling skimming product S _RS diameter for recycling skimming of recycle skimming product S _RP powder S _D drying skimming product S _C mixture skimming was y mixture skimming of Upper limit x Moisture content of the mixed debris

Claims (1)

When continuously performing KR desulfurization of hot metal using an apparatus in which the hot metal is mechanically stirred by rotating the impeller,
With water cooling the skimming product is Haikasu in a series of charge in KR desulfurization to be carried out the succession as a recycle skimming was recycled for skimming prepared by water-cooled, Daikatamari over particle size 40 mm, particle size Powder less than 15mm, the space between them divided into small diameters by particle size,
A part or all of the debris discharged at the temperature of KR desulfurization performed subsequent to the series of charges and capable of vaporizing water is used as a debris for drying.
Mixing the debris for drying and the small diameter recycle debris obtained from the cycle debris to obtain a mixed debris,
When charging the molten material thus obtained into the hot metal at a charge after the KR desulfurization charge obtained from the dried material for dehydration ,
The weight ratio a and the drying time when the weight ratio of the desiccant for drying with respect to the mixed sanitized product is a (%) and the elapsed time from the start of mixing the sanitized product is the drying time b (hr). In addition to obtaining a multiple regression equation represented by the equation (1) for estimating the moisture content x (%) of the dried product after drying with b as a variable,
An upper limit value y (kg / t) of the mixed debris to be introduced and a water content x (( %) To obtain the formula (2),
A small-sized recycling item obtained from the recycling item and the drying item so that the weight ratio of the drying item to the mixed item is a (%). Mix to make a mixed debris,
The mixed demolding product is allowed to stand for a drying time b (hr),
Substituting into the formula (1) the weight ratio “a” of the dry decontamination product to the mixed decontamination product and the drying time b (hr) of the mixed decontamination product, the moisture value x of the mixed decontamination product after drying. Seeking
Substituting the determined moisture content x of the dried product after drying into Equation (2) to obtain the upper limit y (kg / t)
A bullion recycling method in KR desulfurization, wherein the mixed decontaminated material is introduced into the molten iron so that the mixed decontaminated material is less than the calculated input amount upper limit value y (kg / t) .