JP2012201954A - Method for producing forming inhibitory material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a forming inhibitory material by using shredder dust as an alternative of plastics.SOLUTION: In a separation process 301 based on size, for example, shreds with a particle size of about 12 mm or more are separated from shredder dust (301: large). Shreds with a particle size of less than about 12 mm (301: small) are stored as raw materials of the shredder dust (304). In a separation process 302 based on weight, lightweight shreds with small weight are separated from the shreds with a particle size of about 12 mm or more separated in the separation process 301 based on size (302: light). Iron and nonmetal are recovered from heavyweight shreds which are not separated in the separation process 302 based on weight (302: heavy). In a pulverization process 303, the lightweight shreds separated in the separation process 302 based on weight are pulverized into, for example, shreds smaller than about 10 mm, and the pulverized lightweight shreds are stored as raw materials of the shredder dust (304). A blending amount appropriate for producing a forming inhibitory material is removed from the stored shreds.

Description

  The present invention relates to forming slag that is formed during refining in converter steelmaking and is present in the converter or discharged to the hot metal ladle, or from a metallurgical furnace for steel making such as a converter and electric furnace during refining to the hot metal ladle. The present invention relates to a forming suppression material manufacturing method for manufacturing a forming suppression material for calming discharged forming slag.

  For example, in a converter, a large amount of oxygen gas is blown to extract and purify the contained metal from ore and other raw materials. At that time, carbon monoxide and the like become bubbles in the slag floating on the hot metal, so that the slag expands. This phenomenon is called foaming. When forming occurs, the temperature drop during steel output is large, and if the forming slag that flows out of the furnace enters the hot metal ladle, it becomes a factor in operation and quality problems, so it is necessary to calm down early.

The forming slag can be sedated by introducing a forming inhibitor and destroying the forming slag, or by opening a hole in the forming slag and degassing and contracting.
For example, a main raw material is a mixture of at least one of iron ash generated in the steelmaking process (for example, blast furnace ash) and boiler-generated combustion ash for power generation (for example, boiler combustion settled ash) and paper sludge (sludge). It is known that a plastic or the like is added and mixed as a binder (solidifying material), compressed, and molded into a briquette (for example, see Patent Document 1).

The iron-making process generated ash, the boiler ignited combustion ash and the paper sludge, which are raw materials of the forming suppression material disclosed in Patent Document 1, are all pyrolytic substances or contain pyrolytic substances. And can retain an appropriate amount of moisture. When heated to a high temperature, the moisture is decomposed to generate H ₂ gas. Paper sludge and blast furnace ash burn combustible components and generate CO ₂ gas and hydrocarbon gas. These gases degas and form the forming slag.

Furthermore, blast furnace ash is mainly composed of iron oxide powder and carbon, and is effective for adjusting the apparent specific gravity of the forming inhibitor. Boiler combustion sedimentation ash is mainly coal burning husk and has a small carbon component, but its shape is very porous and can take in a large amount of moisture inside.
In addition, the plastic melts at the time of forming the forming suppressing material and serves not only as a binder, but also serves to prevent a decrease in the temperature of the slag because it generates a large amount of heat.

  On the other hand, treatment of shredder dust has become a problem in recent years. Shredder dust is a mixture of pieces of plastic, glass, fibers, etc. left after crushing waste home appliances and automobiles and collecting useful metals.

Shredder dust is disposed of in landfills or reused as fuel for waste incinerators, gasification furnaces, etc., but the importance of reuse increases in order to cope with future shortages of landfill disposal sites. ing.
If shredder dust can be used as an alternative to plastic in the forming suppression material, the reuse destination of shredder dust can be expanded.

JP 2004-225108 A

However, shredder dust may contain debris with a particle size exceeding 10 mm. The forming suppression material must be of a size that settles at a moderate rate and is easy to handle when it is introduced into the forming slag. If fragments having a particle size exceeding 10 mm are contained, it is not desirable because it cannot be molded into an appropriate size and the forming suppression material becomes large.
In addition, the shredder dust may contain chlorine. Chlorine becomes a corrosive factor for steel factory heat exchangers and the like, and incomplete combustion may generate dioxins. For this reason, it is desirable that the concentration of chlorine contained in the forming suppression material is, for example, 0.2% by weight or less.
Further, since shredder dust contains impurities such as glass and fibers, it generates less heat than plastic.
Furthermore, the shredder dust contains impurities, and has a weaker force for bonding the raw materials for forming suppression materials than plastic, and cannot sufficiently function as a binder.

  The objective of this invention is providing the forming suppression material manufacturing method which can manufacture a forming suppression material using shredder dust as a substitute of plastics.

In order to achieve the above object, the forming suppression material manufacturing method of the present invention comprises:
As a raw material, steelmaking process generated ash and / or boiler generated combustion ash, paper sludge, plastic, and a predetermined amount of shredder dust raw material containing only fragments smaller than a predetermined size are included as raw materials. A mixing step of mixing and making a mixture in which the raw materials are mixed;
A molding step of compressing and molding the mixture made in the mixing step;
It is characterized by providing.

Preferably, the forming suppression material manufacturing method of the present invention comprises:
The shredder dust includes one generated from a waste home appliance and / or one generated from a scrap car.

Preferably, the forming suppression material manufacturing method of the present invention comprises:
It is determined whether or not each piece contained in the shredder dust is not less than the predetermined size, and pieces smaller than the predetermined size are selected and stored as the shredder dust raw material, and further, the predetermined size. The above-mentioned debris is selected as a lightweight material having a small weight, and the selected lightweight material is crushed into pieces smaller than the predetermined size, and the crushed lightweight material is stored as the shredder dust raw material. A shredder dust cutting step of cutting out the predetermined amount from the shredder dust raw material,
In the mixing step, the shredder dust raw material cut out in the shredder dust cutting step is used as a raw material.
It is characterized by that.

Preferably, the forming suppression material manufacturing method of the present invention comprises:
In the shredder dust cutting process,
The grizzly feeder sorts out the pieces larger than the predetermined size from the pieces contained in the shredder dust and sends them to the wind power sorter, and drops the pieces smaller than the predetermined size onto the conveyor.
The wind sorter blows off lightweight objects to the crusher by the wind,
The crusher crushes the blown-down lightweight object into pieces smaller than the predetermined size and drops it on the conveyor.
The transport conveyor sends debris dropped from the grizzly feeder and the crusher to a processed hopper,
The processed hopper stores the fallen pieces, and cuts out the predetermined amount from the stored pieces.
It is characterized by that.

Preferably, the forming suppression material manufacturing method of the present invention comprises:
In the shredder dust cutting step, the predetermined amount is adjusted according to the concentration of chlorine contained in the shredder dust,
To suppress chlorine contained in the produced forming suppression material to a predetermined concentration or less,
It is characterized by that.

Preferably, the forming suppression material manufacturing method of the present invention comprises:
The predetermined amount is adjusted in the shredder dust cutting step so that the heat generation amount of the produced forming suppression material exceeds a predetermined heat generation amount and the forming suppression material maintains a predetermined shape after molding, and the mixing is performed. The mixing ratio of the plastic and the shredder dust raw material is adjusted in the process.

  According to the present invention, the forming suppression material can be manufactured using shredder dust as an alternative to plastic.

It is a figure which shows an example of each process included in the forming suppression material manufacturing method which concerns on embodiment of this invention. It is a figure which shows an example of the process in the SR & ASR cutting process in FIG. It is a figure which shows an example of the various apparatuses used at the SR & ASR cutting process in FIG.

  Hereinafter, a forming suppression material manufacturing method according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the forming suppression material manufacturing method according to the embodiment of the present invention includes a kiln drying step 100, a primary blending step 200, an SR & ASR cutting step 300, a secondary blending step 400, and an extrusion molding step. 500, a dry storage process 600, and a dispensing process 700.
Here, SR (Shredder Residue) refers to shredder dust that is generated from waste home appliances and is crushed. ASR (Automobile Shredder Residue) refers to a product that originates from a scrapped vehicle and is crushed by removing airbags, chlorofluorocarbons, and the like from the scrapped vehicle.

In the kiln drying process 100, the input paper sludge (sludge) is dried using a rotary kiln. The paper sludge is generated, for example, in a paper mill and includes short fibers.
In the primary blending process 200, plastic, boiler combustion sedimentation ash, and non-forming forming suppression material determined not to satisfy a predetermined standard in the subsequent dispensing process 700 are charged. In the primary blending process 200, the paper sludge dried in the kiln drying process 100, the plastic, the boiler combustion sedimentation ash, and the non-forming foaming suppression material are mixed using a pug mixer.

Here, a thermoplastic resin that can be used as a plastic can be melted when heated, solidified when cooled, and plastically repeated. For example, polyethylene, polypropylene, polystyrene and the like can be used.
However, polyvinyl chloride cannot be used because it may damage the equipment of the steel mill.

In the SR & ASR cutting process 300, iron and non-ferrous metals are recovered from the SR and / or ASR, and the remaining material is crushed into pieces smaller than a predetermined size to cut out an appropriate blending amount in order to produce a forming inhibitor. Details of the SR & ASR cutting process 300 will be described later.
In addition, a fragment means each lump contained in SR or ASR.
In secondary blending step 400, SR and / or ASR cut out in SR & ASR cutting step 300 and carbonized powder are charged. In the secondary blending process 400, in addition to the paper sludge, plastic, and boiler combustion settled ash mixed in the primary blending process 200, SR and / or ASR and carbonized powder are further mixed using a pug mixer.
Carbonized powder is obtained by incinerating and carbonizing general waste collected at the cleaning center.

In the extrusion molding process 500, the raw material mixed in the secondary blending process 400 is molded into a briquette of a predetermined size using an extrusion molding machine (reduced melting compression molding machine), and is completed as a forming suppression material. When the raw materials for forming suppression material are compressed by an extrusion molding machine, they generate heat at 70 to 90 ° C. due to friction. The plastic functions as a binder by being melted by this frictional heat and mixed with other raw materials and solidified by cooling.
Here, the forming suppression material must be sized so as to settle down at an appropriate speed when it is put into the forming slag and to be handled easily. For this reason, a forming suppression material is shape | molded in the briquette of the shape close | similar to a rectangular parallelepiped whose each side exceeds about 40 mm and whose longest side is about 100 mm or less, for example.

In the dry storage process 600, the foaming suppression material molded in the extrusion molding process 500 is stored and dried.
In the dispensing process 700, for example, a forming suppressor having a particle size exceeding 40 mm (a forming inhibitor having a length, width, and height exceeding 40 mm) is left on the sieve by a sieving machine and is discharged as a product.
The non-forming forming suppression material dropped under the sieve by the sieving machine is returned to the primary blending step 200 and reused as a raw material for the forming suppression material.

Next, details of the SR & ASR cutting process 300 will be described.
In addition to plastic, SR and ASR contain various foreign substances such as bolts, copper wire, aluminum scrap, rubber scrap, and glass. For this reason, in order to use SR and ASR as a substitute for plastics for forming suppression materials, the following four points are problematic.
(1) The particle size of the fragments is large.
Since SR and ASR include fragments having a particle size exceeding 100 mm (fragments whose length, width, or height exceeds 100 mm), they cannot be molded by the extrusion molding process 500.
(2) May contain a large amount of chlorine.
The chlorine contained in the forming inhibitor is preferably 0.2% by weight or less, for example. However, when the SR and ASR samples were analyzed, some contained chlorine at concentrations of 0.89 wt% and 1.51 wt%, respectively.

(3) The calorific value is small compared to plastic.
The calorific value of the plastic was about 7,900 kcal / kg, whereas the calorific values of the SR and ASR samples were about 6,820 kcal / kg and about 6,780 kcal / kg, respectively.
(4) Moldability is inferior compared to plastic.
Compared with plastic, the bonding force of the raw materials of the forming inhibitor is weak, and the briquette shape may not be maintained after molding.

  (1) In order to solve the problem that the particle size of the fragments is large, before mixing SR and / or ASR with other raw materials, in the SR & ASR cutting process 300, iron and non-ferrous metal are removed from SR and / or ASR. The recovered material is crushed into pieces having a particle size of, for example, about 10 mm (both pieces having a length, width, and height of about 10 mm).

Specifically, in the SR & ASR cutting process 300, as shown in FIG. 2, a sorting process 301 by size, a sorting process 302 by weight, and a crushing process 303 are performed.
In the sorting process 301 according to size, for example, a piece having a particle size of about 12 mm or more (a piece having a length, width, or height of about 12 mm or more) is selected (301: large). In order to input fragments (301: small) that have not been sorted in the sorting process 301, for example, fragments having a particle size smaller than about 12 mm (length, width, and height are all shorter than about 12 mm) into the secondary blending process 400 Stored (304). The stored debris contains ferrous and non-ferrous metals, which are effective for increasing the apparent specific gravity of the forming inhibitor.
In the sorting process 302 based on the weight, a lightweight object having a small weight is selected from the pieces having a particle size of about 12 mm or more sorted in the sorting process 301 based on the size (302: light). Iron and non-ferrous metals are recovered from heavy objects that are not sorted by the sorting process 302 based on weight (302: heavy).
In the crushing process 303, the lightweight object selected in the sorting process 302 according to the weight is crushed into, for example, pieces smaller than about 10 mm (fragments whose length, width, and height are all shorter than about 10 mm). Store (304) for input to secondary compounding process 400.
As will be described later, the stored debris is cut into an appropriate blending amount to produce a forming suppression material, and is put into the secondary blending step 400.

In the SR & ASR cutting process 300, as shown in FIG. 3, as shown in FIG. The crusher 317, the conveyor 318, the conveyor 319, and the processed product hopper 320 are used.
The SR and ASR are input to the input hopper 311 and are conveyed to the grizzly feeder 313 by the supply conveyor 312.
The grizzly feeder 313 performs a size selection process 301. Specifically, the grizzly feeder 313 sorts fragments having a particle size of about 12 mm or more from the fragments contained in the SR and ASR, and sends them to the wind power sorter 314. On the other hand, the grizzly feeder 313 drops fragments having a particle size smaller than about 12 mm onto the conveyor 318.

The wind power sorter 314 performs a sorting process 302 based on weight. The wind power sorter 314 blows a lightweight object to the crusher 317 by the wind. The heavy object that has not been blown down falls to the heavy object hopper 315.
The bag filter (filtration dust collecting device) 316 filters and discharges air that has become dirty during the sorting process 301 according to size and the sorting process 302 according to weight.
The crusher 317 performs a crushing process 303. The crusher 317 crushes the blown-down lightweight object into pieces having a particle size smaller than, for example, about 10 mm, and drops it on the conveyor 318.
In addition, since heavy objects are removed by the wind power sorter 314, the crusher 317 may crush only lightweight objects. For this reason, the trouble of the crusher 317 can be reduced.
The conveyor 318 and the conveyor 319 send debris dropped from the grizzly feeder 313 and the crusher 317 to the processed product hopper 320.

The processed product hopper 320 accumulates the sorted and crushed pieces, cuts out an appropriate blending amount to produce the forming suppression material, and inputs it into the secondary blending step 400.
The SR and ASR charged into the secondary blending process 400 contain only fragments having a particle size smaller than 12 mm. For this reason, SR and ASR can be mixed with other raw materials in the secondary blending process 400, and can be formed into a forming inhibitor having an appropriate size in the extrusion molding process 500.

The problem (2) can be solved by adjusting (restricting) the proportion of SR or ASR mixed with the forming inhibitor according to the chlorine concentration.
As described above, analysis of SR and ASR samples detected 0.89 wt% and 1.51 wt% chlorine, respectively. In the case of these samples, the blending ratio for suppressing the chlorine concentration of the forming inhibitor to 0.2% by weight or less can be obtained from the following equations (1) and (2), respectively.
0.2 ÷ 0.89 × 100 = 22% by weight (1)
0.2 ÷ 1.51 × 100 = 13% by weight (2)

From formulas (1) and (2), if the proportion of SR and ASR mixed in the forming inhibitor is limited to 22 wt% or less and 13 wt% or less, respectively, the chlorine concentration of the forming suppressor is 0.2 wt%. It can be seen that the following can be suppressed.
In this way, the chlorine concentration of SR or ASR is measured, and an amount that can suppress the chlorine concentration of the forming inhibitor to a predetermined concentration or less is cut out from the processed product hopper 320 in accordance with the measured chlorine concentration. By adding it to the blending step 400, the chlorine concentration of the forming inhibitor can be suppressed to a predetermined concentration or less.
The chlorine concentrations of 0.89 wt% and 1.51 wt% are merely examples, and it goes without saying that the chlorine concentration is different if the source and date of occurrence of SR and ASR are different.

Moreover, in order to prevent the temperature of the forming slag from being lowered when the forming suppression material is added to the forming slag, it is desirable that the forming suppression material has a calorific value of 3,000 kal / kg or more. The forming suppression material described in Patent Document 1 has a calorific value exceeding 3400 kcal / kg and satisfies a desirable calorific value.
However, as pointed out in problem (3) above, the calorific value of plastic is about 7,900 kcal / kg, whereas the calorific values of SR and ASR samples are about 6,820 kcal / kg and about 6 respectively. 780 kcal / kg, which is smaller than the calorific value of the plastic.
For this reason, if all of the plastic contained in the forming suppression material described in Patent Document 1 is replaced with SR and / or ASR, the calorific value may be less than 3,000 kal / kg.
This is included in the forming suppression material by adjusting (limiting) the amount of SR and ASR mixed in the forming suppression material and increasing the amount of added plastic when the calorific value of SR and ASR is small. This can be prevented by adjusting the blending ratio of SR and / or ASR and plastic to ensure a calorific value of 3,000 kal / kg or more.

  In addition, as pointed out in the problem (4) above, if the briquette shape (shape close to a rectangular parallelepiped) cannot be maintained after molding simply by mixing SR and / or ASR, similarly, a forming inhibitor Adjust (limit) the amount of SR and ASR mixed in the resin and increase the amount of plastic to be added to adjust the blending ratio of SR and / or ASR and plastic contained in the forming suppression material. By increasing, the shape of the briquette can be maintained after molding.

  As described above, the SR and / or ASR is formed by selecting and crushing the fragments contained in the SR and / or ASR, and adjusting the proportion of the total plastic contained in the forming suppression material by adding plastic. It can be used as a raw material for the suppressor.

A forming inhibitor (hereinafter, referred to as a conventional forming inhibitor) used in a conventional steel factory has, for example, the following composition.
Paper sludge 32%, Plastic 21%, Power generation boiler generated combustion ash 32%, Carbonized powder 4%, Non-forming forming inhibitor 12%
Conventional forming suppression materials have good moldability and high strength. Moreover, this has sufficient calorific value and an apparent specific gravity is 1.0-1.5 g / cm < ³ >. When this forming suppression material is put into the converter or the hot metal ladle, it can be quickly mixed into the forming slag layer and the forming slag can be quickly sedated.

The forming suppression material manufactured using the forming suppression material manufacturing method according to the present embodiment (hereinafter referred to as the forming suppression material of the present embodiment) is dried for 24 hours after extrusion molding, and the moldability is increased by a sieving machine the next day. As a result of confirmation, although the strength was slightly inferior to that of the conventional forming suppression material, powder was hardly generated and the product had sufficient strength.
Some of the forming suppression materials of this embodiment include iron having a particle size of 12 mm or less, and the apparent specific gravity exceeds 2.0 g / cm ^3. apparent specific gravity similar to the suppressor was almost ^{1.1g / cm 3 ~1.4g / cm 3} .
And at a later date, it was confirmed that the forming suppression material of the present embodiment was actually used and the forming slag could be quickly sedated in the same manner as the conventional forming suppression material.

  ASR usually contains more plastic than SR and contains less non-ferrous metal. For this reason, ASR can raise a compounding rate as a raw material of a forming suppression material rather than normal SR.

  Moreover, in the forming suppression material manufacturing method of this invention, it is not necessary to use a carbonized powder and / or a non-forming forming suppression material as a raw material, for example. The iron ash generated from the ironmaking process may be used as a raw material instead of the boiler generated combustion ash for power generation, and both the boiler ash generated from the power generation and the iron ash generated from the iron making process may be used as a raw material.

In the above-described embodiment, heavy and light materials are sorted by the wind power sorter 314. However, in the forming suppression material manufacturing method of the present invention, specific gravity sorting by liquid or sorting by magnetic / electrical adsorption may be used. .
Moreover, although the example which shape | molds with an extrusion molding machine in the extrusion molding process 500 was shown, in the forming suppression material manufacturing method of this invention, you may compress and shape | mold by another method.
Further, in the above-described embodiment, when the calorific value of SR and ASR is small, or when the shape of the briquette (shape close to a rectangular parallelepiped) cannot be maintained after molding, the amount of added plastic is increased. In the forming suppression material manufacturing method of the present invention, the amount of the non-forming forming suppression material added may be increased.

As described above, according to the present invention, the forming suppression material can be manufactured using shredder dust (ASR and / or SR) as a substitute for plastic.
In recent years, the demand for plastics in other industries has increased, and it is becoming difficult to procure plastics. By producing with the forming suppression material manufacturing method according to the present invention, the necessary amount of forming suppression material due to the shortage of plastics. It will be easier to avoid the situation that can not be produced.

  Moreover, since shredder dust may contain lead, cadmium, and chlorine, most of them are disposed of in landfills. Since the forming suppression material manufacturing method according to the present invention uses shredder dust, which has been conventionally discarded, as a raw material, the procurement cost of the raw material is low. For this reason, the manufacturing cost of a forming suppression material can be reduced.

  Although the embodiments of the present invention have been described above, various modifications and combinations necessary for design reasons and other factors are described in the inventions described in the claims and the specific embodiments described in the embodiments of the invention. It is included in the scope of the invention corresponding to the example.

DESCRIPTION OF SYMBOLS 100 ... Kiln drying process, 200 ... Primary compounding process, 300 ... SR & ASR cutting process, 301 ... Sorting process by size, 302 ... Sorting process by weight, 303 ... Crushing process, 311 ... Feeding hopper, 312 ... Feeding conveyor, 313 ... Grizzly feeder, 314 ... Grizzly feeder, 315 ... Grizzly feeder, 316 ... Grizzly feeder, 317 ... Grizzly feeder, 318, 319 ... Conveyor, 320 ... Processed hopper, 400 ... SR & ASR cutting process, 500 ... Extrusion molding process , 600 ... Dry storage process, 700 ... Dispensing process

Claims (6)

As a raw material, steelmaking process generated ash and / or boiler generated combustion ash, paper sludge, plastic, and a predetermined amount of shredder dust raw material containing only fragments smaller than a predetermined size are included as raw materials. A mixing step of mixing and making a mixture in which the raw materials are mixed;
A molding step of compressing and molding the mixture made in the mixing step;
A forming suppression material manufacturing method comprising:   2. The forming suppression material manufacturing method according to claim 1, wherein the shredder dust includes one generated from a waste home appliance and / or one generated from a scrap automobile. 3. It is determined whether or not each piece contained in the shredder dust is not less than the predetermined size, and pieces smaller than the predetermined size are selected and stored as the shredder dust raw material, and further, the predetermined size. The above-mentioned debris is selected as a lightweight material having a small weight, and the selected lightweight material is crushed into pieces smaller than the predetermined size, and the crushed lightweight material is stored as the shredder dust raw material. A shredder dust cutting step of cutting out the predetermined amount from the shredder dust raw material,
In the mixing step, the shredder dust raw material cut out in the shredder dust cutting step is used as a raw material.
The forming suppression material manufacturing method according to claim 1 or 2, characterized by things. In the shredder dust cutting process,
The grizzly feeder sorts out the pieces larger than the predetermined size from the pieces contained in the shredder dust and sends them to the wind power sorter, and drops the pieces smaller than the predetermined size onto the conveyor.
The wind sorter blows off lightweight objects to the crusher by the wind,
The crusher crushes the blown-down lightweight object into pieces smaller than the predetermined size and drops it on the conveyor.
The transport conveyor sends debris dropped from the grizzly feeder and the crusher to a processed hopper,
The processed hopper stores the fallen pieces, and cuts out the predetermined amount from the stored pieces.
The forming suppression material manufacturing method according to claim 3. In the shredder dust cutting step, the predetermined amount is adjusted according to the concentration of chlorine contained in the shredder dust,
To suppress chlorine contained in the produced forming suppression material to a predetermined concentration or less,
The forming suppression material manufacturing method according to claim 3 or 4 characterized by things.   The predetermined amount is adjusted in the shredder dust cutting step so that the heat generation amount of the produced forming suppression material exceeds a predetermined heat generation amount and the forming suppression material maintains a predetermined shape after molding, and the mixing is performed. The forming suppression material manufacturing method according to any one of claims 3 to 5, wherein a mixing ratio of the plastic and the shredder dust raw material is adjusted in the process.

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