JP4657281B2 - Waste gypsum recycling plant and waste gypsum recycling method - Google Patents

Description

  The present invention relates to a waste gypsum recycling plant and a waste gypsum recycling method suitable for recycling, for example, waste gypsum derived from waste gypsum board.

  In recent years, the amount of waste gypsum board discharged has been increasing among the building waste materials that are generated with the dismantling of buildings. Gypsum board is formed by sticking paper on both sides of a platy core made of dihydrate gypsum, and is often used for ceilings and partitions, and the production volume is still increasing. Accordingly, the amount of waste gypsum board discharged is expected to increase further in the future.

  Conventionally, waste gypsum board has been finally disposed of as industrial waste by landfill. However, in final disposal by landfill, the amount of waste gypsum board discharged may reach the limit of processing capacity. In addition, a problem has been reported that the landfilled waste gypsum board is reduced by the action of microorganisms to generate hydrogen sulfide gas and sulfide, causing contamination of the surrounding environment. Thus, in the situation where various problems exist in the final disposal of waste gypsum board, there is an increasing demand for recycling industrial waste from the viewpoint of environmental protection.

  Therefore, recently, in order to make it possible to use waste gypsum board as a recycling resource, a recycling apparatus that crushes waste gypsum board and efficiently separates waste gypsum board into waste gypsum and waste paper has been proposed (see, for example, Patent Document 1). ). Since the main component of waste gypsum is dihydrate gypsum, it is calcined at a temperature of 130 to 150 ° C. and dehydrated to obtain hemihydrate gypsum. Hemihydrate gypsum has the property that, when given water, it hardens in a short time by a hydration reaction and returns to dihydrate gypsum.

As a method for recycling waste gypsum, there is a method in which waste gypsum is calcined in a rotary kiln to produce hemihydrate gypsum. The fired product fired in the rotary kiln is put into a cooling box containing a heat exchange pipe through which a refrigerant flows, cooled by heat exchange with the refrigerant, and then packed in a flexible container bag (flexible container bag).
JP 2007-245023 A

  However, dihydrate gypsum that constitutes waste gypsum board has a property of absorbing water, and the amount of water contained varies depending on the state of use in buildings, dismantling and transportation conditions. Therefore, the waste gypsum separated from the waste gypsum board also varies in water content. For this reason, in the conventional recycling method of waste gypsum, it is necessary to adjust the firing time and firing temperature of waste gypsum according to the amount of moisture, and there is a problem that it takes time and effort for the firing operation. As a result, it is difficult to increase the efficiency of the waste gypsum recycling process, and it is difficult to cope with the increase in the amount of waste gypsum board discharged.

  In addition, because there is variation in the amount of water in the waste gypsum, adjusting the firing time and the firing temperature to dehydrate and fire the part of the waste gypsum that is fired in the rotary kiln will reduce the amount of water. The part is calcined excessively to produce anhydrous gypsum. Anhydrous gypsum is difficult to proceed with hydration as compared with hemihydrate gypsum, and there is a large difference in physical properties. Therefore, the product produced by the conventional recycling method of waste gypsum has a problem that hemihydrate gypsum and anhydrous gypsum are mixed and the quality is poor. Furthermore, since the water content of waste gypsum varies, there is a problem that the ratio of hemihydrate gypsum and anhydrous gypsum contained in the product varies and the quality of the product is unstable.

  Therefore, an object of the present invention is to provide a recycling plant for waste gypsum that can improve the efficiency of recycling processing of waste gypsum, and that can obtain regenerated gypsum with good quality and stability.

In order to solve the above-mentioned problems, the waste gypsum recycling plant of the present invention is a waste gypsum recycling plant for processing waste gypsum to produce semi-gypsum and anhydrous gypsum,
A pretreatment device that pretreats waste gypsum powder to reduce variation in moisture content;
A baking apparatus for baking powder with reduced water content to produce hemihydrate gypsum and anhydrous gypsum;
The calcined powder is divided into a small particle size powder that is a powder having a particle size smaller than a reference particle size of 50 μm and a large particle size powder that is a powder having a particle size larger than the reference particle size. It is characterized by having a classification device for dividing.

According to the said structure, the dispersion | variation in the moisture content of the waste gypsum powder is reduced by the pretreatment device. By baking the powder with a baking apparatus, hemihydrate gypsum (CaSO ₄ 1 / 2H ₂ O) and anhydrous gypsum (CaSO ₄ ) are generated from dihydrate gypsum (CaSO ₄ .2H ₂ O) contained in the waste gypsum. The Since the variation in the moisture content of the powder during firing by the firing apparatus is reduced, it is possible to reduce the trouble of adjusting the firing temperature and the firing time corresponding to the variation in the moisture content. In addition, it is possible to prevent inconvenience that the generation ratio of hemihydrate gypsum and anhydrous gypsum varies due to variation in water content. By classifying the fired powder based on a predetermined reference particle size with a classifier, a small particle size powder mainly containing anhydrous gypsum, and a large particle size powder mainly containing hemihydrate gypsum, Can be divided into

  Thus, a pretreatment device that reduces the variation in the moisture content of the waste gypsum powder, a firing device that fires the powder with reduced variation in the moisture content, and the calcined powder as a small particle size powder. High-quality anhydrous gypsum and hemihydrate gypsum from waste gypsum separated from waste gypsum board, for example, with a variation in water content, by a waste gypsum recycling plant equipped with a classification device that classifies it into a large particle size powder Can be generated stably and efficiently.

Moreover, according to the said structure , it classifies based on the reference | standard particle size of 50 micrometers, From the baked powder, the small particle size powder mainly containing anhydrous gypsum and the large particle size mainly containing hemihydrate gypsum It can be effectively divided into powder.

  In one embodiment of the waste gypsum recycling plant, the pretreatment device is an air dryer.

  According to the above-described embodiment, it is possible to effectively reduce the amount of water in a portion where the amount of water locally present in the waste gypsum powder is excessive, thereby reducing variation in the amount of water.

  In one embodiment of the waste gypsum recycling plant, the baking apparatus is a rotary kiln.

  According to the above embodiment, waste gypsum powder can be fired to produce anhydrous gypsum and hemihydrate gypsum.

  In one embodiment of the waste gypsum recycling plant, the classification device is a cyclone classifier.

  According to the above-described embodiment, the fired powder is effectively classified based on a predetermined reference particle size, a small particle size powder mainly containing anhydrous gypsum, and a large particle mainly containing hemihydrate gypsum. It can be efficiently divided into diameter powders.

  The waste gypsum recycling plant of one embodiment is provided with the air flow cooler which cools the powder calcined with the above-mentioned calcining device.

  According to the embodiment, the fired powder can be cooled with high efficiency in a short time.

  The waste gypsum recycling plant of one embodiment is connected between the pretreatment device and the calcining device, and the particle size smaller than the reference particle size from the powder in which the variation in water content is reduced by the pretreatment device. Equipped with a pre-firing classification device for removing the gypsum.

  According to the above embodiment, anhydrous gypsum produced by the pretreatment device is fired by taking out powder smaller than a predetermined reference particle diameter from the powder whose variation in water content is reduced by the pretreatment device. Can be sorted before sending to the device. Thereby, the baking process by a baking apparatus can be made more efficient.

  The waste gypsum recycling plant of one embodiment is formed so as to continuously generate the small particle size powder and the large particle size powder from the waste gypsum powder.

  In the conventional recycling method of waste gypsum, since the range of adjustment of the firing time and the like is relatively large due to the variation in the amount of water when firing with the rotary kiln, the firing process is limited to batch processing. On the other hand, according to the present embodiment, a pretreatment device that reduces variation in the amount of water contained in the waste gypsum powder, a firing device that fires powder with reduced variation in moisture content, and firing Since it combines with a classifier that separates the generated powder based on the standard particle size, the time and effort to adjust the firing time of the firing device according to the amount of water in the waste gypsum is reduced as before. A continuous treatment for continuously producing water gypsum and anhydrous gypsum becomes possible. Therefore, it is possible to improve the efficiency of the waste gypsum recycling process, and it is possible to cope with an increase in the amount of waste gypsum board that is expected in the future.

A waste gypsum recycling method according to another aspect of the present invention is a waste gypsum recycling method for producing half gypsum and anhydrous gypsum by treating waste gypsum,
A pretreatment process to reduce the variation in the water content of the waste gypsum powder;
Firing a powder with reduced variation in moisture content to produce hemihydrate gypsum and anhydrous gypsum;
The fired powder is divided into a small particle size powder that is a powder having a particle size smaller than a reference particle size of 50 μm and a large particle size powder that is a powder having a particle size larger than the reference particle size. It is characterized by comprising a classification process.

  According to the said structure, the dispersion | variation in the moisture content of the powder of waste gypsum is reduced by a pre-processing process. In the baking process, hemihydrate gypsum and anhydrous gypsum are produced from dihydrate gypsum contained in waste gypsum. In this firing step, the powder has a reduced moisture content in the pretreatment step, so that the time and effort for adjusting the firing temperature and firing time can be reduced in response to the moisture content variation. In addition, it is possible to prevent inconvenience that the generation ratio of hemihydrate gypsum and anhydrous gypsum varies due to variation in water content. In the classification step, the fired powder is classified based on a predetermined reference particle size, so that a small particle size powder mainly containing anhydrous gypsum and a large particle size powder mainly containing hemihydrate gypsum. Can be divided.

  Thus, a pretreatment process for reducing the variation in the moisture content of the waste gypsum powder, a firing process for firing the powder with a reduced variation in the moisture content, and the fired powder into a small particle size powder. And classifying the large particle size powder into high-quality anhydrous gypsum and hemihydrate gypsum from waste gypsum that is crushed and separated, for example, from waste gypsum board with varying moisture content. Stable and efficient separation can be generated.

  According to the present invention, variation in the water content of waste gypsum is reduced by a pretreatment device, hemihydrate gypsum and anhydrous gypsum are produced from dihydrate gypsum contained in waste gypsum by a baking device, and powder after baking by a classification device By classifying the body based on a predetermined standard particle size, a small particle size powder mainly containing anhydrous gypsum and a large particle size powder mainly containing hemihydrate gypsum are generated efficiently and stably. be able to. Therefore, it is possible to cope with an increase in the amount of waste gypsum board discharged expected in the future, and to produce high-quality recycled gypsum that can be reused.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing a waste gypsum recycling plant as an embodiment of the present invention. The waste gypsum recycling plant 1 regenerates waste gypsum separated from waste gypsum board as building waste material to produce anhydrous gypsum and hemihydrate gypsum. The waste gypsum recycling plant 1 includes a gypsum silo 11, a cage mill 12, an air flow dryer 2 as a pretreatment device, a first cyclone classifier 3 as a pre-firing classification device, a rotary kiln 4 as a calcining device, The airflow cooler 5, a second cyclone classifier 6 as a classifier, and a dust collector 7 are roughly configured.

  The gypsum silo 11 is configured to temporarily store waste gypsum crushed pieces, cut out the crushed pieces by a screw conveyor 111 provided at the lower end, and send them to the cage mill 12.

  The cage mill 12 includes a casing having a waste gypsum fragment supply port and a hot air intake port, and two rotors arranged in the casing. The rotor has an annular side plate connected to the drive shaft of the motor, and a plurality of rods protruding from the side plate in parallel with the rotation shaft. The rods of the two rotors are fixed to the side plate so as to form circles having different diameters. These rotors are arranged concentrically so that the trajectories of the rods accompanying rotation overlap each other in the radial direction. These rotors are driven to rotate in opposite directions. The cage mill 12 configured in this manner guides the waste gypsum fragments supplied from the supply port into the casing to the vicinity of the rotation shafts of the two rotors together with the hot air of about 500 ° C. sucked from the intake port, and rotates reversely to each other. Crush with a rod to make. The powder formed by pulverizing the waste gypsum fragments is discharged together with hot air (conveyance air) from an outlet provided on the side of the rotor.

  The hot air supplied to the cage mill 12 is generated by a combustion burner 13 using RPF as fuel, and ash is removed by a cyclone separator 14.

  The air dryer 2 is connected to a first rising pipe 21 that extends in a substantially vertical direction and flows powder and conveying air upward, and to the downstream side of the first upper extending pipe 21, and flows the powder and conveying air downward. A first bent pipe 22 to be changed in direction, an enlarged descending pipe 23 connected to the downstream side of the first bent pipe 22 and having a diameter larger than the diameters of the first rising pipe 21 and the first bent pipe 22; Connected to the downstream side of the diameter descending pipe 23, the second bent pipe 24 for changing the flow of the powder and the conveying wind upward, and connected to the downstream side of the second bent pipe 24, the powder and the conveying wind are moved upward. A second riser 25 that flows through The downstream side of the second riser 25 is bent at a substantially right angle and connected to the first cyclone classifier 3. The air dryer 2 transfers the powder supplied from the cage mill 12 to the upstream end of the first ascending pipe 21 from the first ascending pipe 21 to the second ascending pipe 25 by the conveying air. The conveying air has dropped to a temperature of about 70 ° C. In the process of transferring the powder by the conveying wind, by changing the flow direction in the first and second bent pipes 22, 24, increasing the diameter in the diameter lowering pipe 23, reducing the diameter in the second bent pipe 24, etc. The powder is formed to be stirred and dried.

  The first cyclone classifier 3 includes a cylindrical portion 31 provided with a suction port on a side surface, an inverted conical separating portion 32 that is connected to a lower portion of the cylindrical portion 31 and forms a swirling flow therein, and a cylindrical portion 31. And an exhaust pipe 33 provided inside from the top to the separation section 32, and an exhaust pipe 33 connected to the upper end of the exhaust pipe and protruding from the upper end surface of the separation section. Connected to the exhaust pipe 33 is a sirocco-type blower 15 that sucks the conveyance air from the first cyclone classifier 3. A fixed amount feeder 16 is connected to the lower end of the separation unit 32 via a rotary valve 34 for discharging the separated powder.

  The first cyclone classifier 3 sucks powder and conveying air from the suction port of the cylindrical portion 31 and sends it to the separating unit 32. The centrifugal force of the swirling flow generated by the separating unit 32 removes the powder from the conveying air. It is formed so as to be separated and discharged from the rotary valve 34 to the metering feeder 16. The first cyclone classifier 3 is set to separate powder having a particle size larger than 50 μm, which is the same as a reference particle size described later, from the conveying air. The powder smaller than 50 μm is discharged from the exhaust pipe 33 together with the conveying air and is sent to the dust collector 7 via the blower 15.

  The fixed amount feeder 16 has a storage unit 161 for storing powder, a screw conveyor 162 provided at the bottom of the storage unit 161, and a rotary valve 163 provided at the outlet of the screw conveyor 162. The powder separated by the cyclone classifier 3 is formed so as to be quantitatively supplied to the rotary kiln 4.

  The rotary kiln 4 communicates with a screw conveyor 41 that guides powder from the constant amount feeder 16, a supply unit 42 to which powder is supplied, and the supply unit 42, and is rotationally driven with a gentle downward gradient provided therein. The rotary furnace 43, a discharge unit 44 communicating with the downstream side of the rotary furnace 43, and a screw conveyor 45 that discharges powder from the discharge unit 44 are provided. The discharge unit 44 is provided with an intake port 441 for sucking hot air generated by the combustion burner 13, and the hot air sucked from the intake port 441 flows from the discharge unit 44 through the rotary furnace 43 to the supply unit 42. The discharge port 421 provided in the supply unit 42 is discharged. Hot air from the combustion burner 13 is set to a temperature of about 150 to 170 ° C. in the rotary furnace 43. A sirocco-type blower 17 that sucks hot air discharged from the rotary kiln 4 is connected to the exhaust port 421.

  The rotary kiln 4 is a counter flow type, and the rotary furnace 43 feeds the powder from the supply unit 42 to the discharge unit 44 side while stirring the powder, and flows hot air in the direction opposite to the powder feed direction. Is fired with hot air.

  The air flow cooler 5 has the same structure as that of the air flow dryer 2, and includes a first rising pipe 51, a first bent pipe 52, a diameter-expanding down pipe 53, a second bent pipe 54, and a second rising pipe. 55. The downstream side of the second riser 55 is bent at a substantially right angle and connected to the second cyclone classifier 6. This air flow cooler 5 changes the flow direction in the first and second bent pipes 22, 24 and decreases the diameter in the process of transferring the powder from the first ascending pipe 51 to the second ascending pipe 55 by the conveying air. The powder is stirred and cooled by increasing the diameter of the tube 23 or decreasing the diameter of the second bent tube 24.

  The second cyclone classifier 6 includes a cylindrical portion 61 provided with a suction port on a side surface, an inverted conical separation portion 62 that is connected to the lower side of the cylindrical portion 61 and forms a swirling flow therein, and a cylindrical portion 61. An exhaust pipe provided inside from the top toward the separation part 62, an exhaust pipe 63 projecting from the upper end surface of the separation part and connected to a lower end of the separation part 62, and separated by the separation part 62 It has the storage part 64 which stores the powder which was done temporarily. The storage unit 64 is connected to a sirocco-type blower 65 that pushes air into the storage unit 64. The powder stored in the storage unit 64 is discharged from a rotary valve 66 provided at the lower end, and is formed so that a predetermined amount is packed into the flexible container bag 191 by the platform scale device 19. On the other hand, the exhaust pipe 63 is connected to a sirocco-type blower 18 that sucks the conveying air from the second cyclone classifier 6.

  The second cyclone classifier 6 sucks the powder and conveying air from the suction port of the cylindrical portion 61 and sends it to the separation unit 62, and the powder is conveyed from the conveying air by the centrifugal force of the swirling flow generated by the separation unit 62. To separate. The separated powder is sucked into the storage unit 62 and accumulated in the lower part of the storage unit 62. The second cyclone classifier 6 is configured to separate a large particle size powder having a reference particle size larger than 50 μm from the conveying air, accumulate it in the storage unit 62, and send it to the platform scale device. The powder smaller than 50 μm is discharged from the exhaust pipe 63 together with the conveying air and sent to the dust collector 7 via the blower 18.

  The dust collector 7 collects dust with a bag filter, filters the conveying air supplied from the first cyclone classifier 3, the rotary kiln 4 and the second cyclone classifier 6, and has a small particle size of 5 to 50 μm. It is formed to collect the body. The collected small particle size powder is formed so as to be collected in a powder container 72 via a rotary valve 71 at the lower end. The exhaust gas after filtering the small particle size powder is discharged to the outside through the exhaust port 73.

  The waste gypsum recycling plant 1 having the above-described configuration operates as follows. First, the waste gypsum crushed material separated from the waste gypsum board by a separation device (not shown) is put into the gypsum silo 11 and stored. The main component of the waste gypsum stored in the gypsum silo 11 is dihydrate gypsum, and the amount of water varies depending on the state of use and recycling process of the waste gypsum board. The waste gypsum stored in the gypsum silo 11 is supplied to the cage mill 12 by the screw conveyor 111 at a predetermined conveyance speed.

  In the cage mill 12, waste gypsum fragments are pulverized into powder, mixed with hot air at 500 ° C., and sent to the air dryer 2.

  In the air dryer 2, the powder is agitated and dried in the process of being transported through a flow path that bends, expands and contracts by a transport air of about 70 ° C. As a result, the excessive portion of the moisture content that existed locally due to the dismantling and transporting situation of the waste gypsum board disappeared, the moisture content of each portion was about 30% or less, and the moisture content was uneven. Reduced. Of the powder dried by the air flow dryer 2, a small particle size powder having a particle size smaller than 50 μm is separated by the first cyclone classifier 3 and sent to the dust collector 7. The powder having a particle size larger than 50 μm is temporarily stored in the storage unit 161 of the constant flow feeder 16 and sent to the rotary kiln 4 by the screw conveyor 162.

  In the rotary kiln 4, the powder dihydrate gypsum is dehydrated by hot air at 150 to 170 ° C. to produce hemihydrate gypsum. A part of the powder is dehydrated and becomes anhydrous gypsum. The powder fired in the rotary kiln 4 is quickly cooled in the air flow cooler 5 in the process of being conveyed by the conveying air through the flow path that bends, expands and contracts.

  The cooled powder is separated into a large particle size powder larger than 50 μm and a small particle size powder smaller than 50 μm by the second cyclone classifier 6. In the second cyclone classifier 6, the powder is classified with high efficiency by the pushing effect by the blower 65 and the suction effect by the blower 18.

  The large particle size powder separated by the second cyclone classifier 6 is stored in the storage unit 64, then cut out by the rotary valve 66, supplied to the platform scale device 19, and packed in the flexible container bag 191.

  The small particle size powder separated by the second cyclone classifier 6 is sent to the dust collector 7 and filtered together with the small particle size powder contained in the conveying air sent from the first cyclone classifier 3 and the rotary kiln 4, Collected in a powder container 72. The powder container 72 collects a powder having a small particle diameter of 5 to 50 μm.

  As described above, according to the waste gypsum recycling plant 1 of the present embodiment, when the rotary kiln 4 is baked, the moisture content of the powder is reduced to about 30% or less, which reduces the variation. Correspondingly, the trouble of adjusting the firing temperature and firing time can be reduced. Further, by classifying the powder fired in the rotary kiln 4 based on the reference particle size of 50 μm, the large particle size powder in which hemihydrate gypsum is approximately 90% or more and the anhydrous gypsum is approximately 90% or more. It can be separated into small particle size powder. As described above, the air flow dryer 2 for reducing the variation in the moisture content of the waste gypsum powder, the rotary kiln 4 for firing the powder with reduced variation in the moisture content, and the fired powder into a small particle size powder. And a second cyclone classifier 6 for classifying the powder into a large particle size powder, so that high-quality anhydrous gypsum and hemihydrate gypsum can be used even if the waste gypsum has a portion with a large amount of water locally. It can be separated and played back stably. In particular, since it is not necessary to adjust the firing temperature and firing time of the rotary kiln 4 according to the amount of water as in the prior art, the powder can be fired continuously, and therefore the waste gypsum recycling plant of this embodiment. 1 can be operated continuously. As a result, the waste gypsum recycling plant 1 can sufficiently cope with the expected increase in the amount of waste gypsum board discharged in the future and can produce high-quality recycled gypsum.

  The combustion burner 13 that supplies hot air to the cage mill 12 and the rotary kiln 4 uses RPF, which is a regenerated fuel, and therefore promotes the effective use of resources in combination with the recycling effect of the waste gypsum by the waste gypsum recycling plant 1. be able to.

  The hemihydrate gypsum regenerated in the waste gypsum recycling plant 1 of this embodiment can be reused as, for example, a ground improvement material. Specifically, hemihydrate gypsum undergoes a hydration reaction in a relatively short time when water is added, and changes to dihydrate gypsum and hardens. Therefore, by mixing and compacting hemihydrate gypsum with organic soil or soft clay having a high water content, the water of organic soil or soft clay absorbs and hardens the water, and the ground strength can be increased. Moreover, since dihydrate gypsum is neutral, it has less influence on the environment than strong alkali lime and cement-based solidified materials that have been used as conventional ground improvement materials.

Here, since dihydrate gypsum is water-soluble, it is preferable to reduce water-solubility, for example, by adding cement-type additives, such as blast furnace cement B type. By adding a cement-based additive, not only the water solubility can be reduced, but the strength can be further improved. For example, a ground improvement material obtained by mixing gypsum: cement-based additive at a ratio of 85:15 can absorb 30% of water and exhibit a compressive strength of 90 kN / m ² .

  In this way, by using hemihydrate gypsum obtained by recycling waste gypsum as a ground improvement material, it is possible to effectively use resources and reduce the impact on the environment, thereby contributing to the protection of the global environment. Can do.

  In the above embodiment, the small particle size powder is separated from the pretreated powder by the first cyclone classifier 3, but the first cyclone classifier 3 is not necessarily provided.

  Moreover, the temperature of the hot air supplied to the cage mill 12 and the rotary kiln 4 can be changed as appropriate.

It is a schematic diagram which shows the waste gypsum recycling plant as embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Waste gypsum recycling plant 2 Airflow dryer 3 1st cyclone classifier 4 Rotary kiln 5 Airflow cooler 6 2nd cyclone classifier 7 Dust collector 12 Cage mill 13 Combustion burner 19 Platform weighing device

Claims (8)

A waste gypsum recycling plant for treating waste gypsum to produce semi-gypsum and anhydrous gypsum,
A pretreatment device that pretreats waste gypsum powder to reduce variation in moisture content;
A baking apparatus for baking powder with reduced water content to produce hemihydrate gypsum and anhydrous gypsum;
The calcined powder is divided into a small particle size powder that is a powder having a particle size smaller than a reference particle size of 50 μm and a large particle size powder that is a powder having a particle size larger than the reference particle size. A waste gypsum recycling plant comprising a classification device for dividing. In the waste gypsum recycling plant according to claim 1,
A waste gypsum recycling plant, wherein the pretreatment device is an air dryer. In the waste gypsum recycling plant according to claim 1,
The waste gypsum recycling plant, wherein the baking apparatus is a rotary kiln. In the waste gypsum recycling plant according to claim 1,
The waste gypsum recycling plant, wherein the classification device is a cyclone classifier. In the waste gypsum recycling plant according to claim 1,
A waste gypsum recycling plant comprising an air flow cooler for cooling the powder fired by the firing device. In the waste gypsum recycling plant according to claim 1,
A pre-firing classifying device connected between the pretreatment device and the calcining device and for extracting a powder having a particle size smaller than the reference particle size from the powder whose variation in moisture content is reduced by the pretreatment device; A waste gypsum recycling plant characterized by comprising. In the waste gypsum recycling plant according to claim 1,
A waste gypsum recycling plant formed so as to continuously generate the small particle size powder and the large particle size powder from the waste gypsum powder. A waste gypsum recycling method for treating waste gypsum to produce semi-gypsum and anhydrous gypsum,
A pretreatment process to reduce the variation in the water content of the waste gypsum powder;
Firing a powder with reduced variation in moisture content to produce hemihydrate gypsum and anhydrous gypsum;
The fired powder is divided into a small particle size powder that is a powder having a particle size smaller than a reference particle size of 50 μm and a large particle size powder that is a powder having a particle size larger than the reference particle size. A waste gypsum recycling method comprising a classification step.

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