Method of producing solidifying material

Abstract

To provide a method of producing a solidifying material enabling the reuse of gypsum included in a waste gypsum board.SOLUTION: A method of producing a solidifying material according to the embodiment of the present invention comprises a heating step of heating gypsum separated from a waste gypsum board in a temperature range and for a time period such that the gypsum becomes hemihydrate gypsum, a mixing step of mixing the hemihydrate gypsum formed in the heating step and a mixing material in an amount corresponding to the amount of the hemihydrate gypsum, and a feeding step of feeding the hemihydrate gypsum and the mixing material mixed by the mixing step into a transportation container. Thus, a relatively large amount of hemihydrate gypsum can be reused as a portion of a solidifying material, and an improvement in the recycle rate of a gypsum board can be expected under the current situation in which recycling of discarded gypsum boards is hardly progressing. Water purification sludge can also be reused.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a solidifying material. [Background technology]

[0002] For example, Patent Document 1 discloses a method for producing a solidification material, which includes a step of producing gypsum hemihydrate by crushing, separating, and heating discarded gypsum boards, and a step of mixing the produced gypsum hemihydrate, the purified water sludge, and quicklime, slaked lime, or cement so that the produced gypsum hemihydrate is 45 to 65 weight percent and the dried purified water sludge is 5 weight percent or more. Furthermore, Patent Document 2 discloses a method for recycling waste gypsum board in which both sides of a gypsum core material are covered with board base paper, in which the board base paper is not separated from the core material, but is left integrated with the core material, and the whole is crushed and dried to use as a sludge improvement agent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-055240 A [Patent Document 2] JP 2007-161895 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a method for producing a solidification material that can reuse gypsum contained in waste gypsum boards. [Means for solving the problem]

[0005] The method for producing a solidification material according to the present invention includes a heating step of heating the gypsum separated from waste gypsum board at a temperature and for a time period at which the gypsum becomes gypsum hemihydrate, a mixing step of mixing the gypsum hemihydrate produced by the heating step with an amount of an admixture corresponding to the amount of the gypsum hemihydrate, and a loading step of loading the gypsum hemihydrate and the admixture mixed by the mixing step into a transport container.

[0006] Preferably, the method further includes a heat dissipation step of dissipating heat from the hemihydrate gypsum and the mixed material placed in the transport container in an environment in which contact with the outside air is limited.

[0007] Preferably, in the mixing step, the hemihydrate gypsum, the purified water sludge, and the quicklime, slaked lime, or cement are mixed so that the hemihydrate gypsum is 45 weight percent or more and 65 weight percent or less, and the dried purified water sludge is 5 weight percent or more.

[0008] Preferably, the transport container contains a polyethylene material inside, and in the introducing step, the mixed hemihydrate gypsum and the admixture are introduced into the transport container so as to be covered with the polyethylene material.

[0009] Preferably, the method further includes a moisture content adjusting step of adjusting the moisture content of the purified water sludge by using superheated steam so that the moisture content is less than 11%, and in the mixing step, the hemihydrate gypsum is mixed with a mixture containing the purified water sludge whose moisture content has been adjusted in the moisture content adjusting step. Effect of the Invention

[0010] According to the present invention, the gypsum contained in waste gypsum boards can be reused. [Brief description of the drawings]

[0011] [Figure 1] 1 is a flowchart illustrating a manufacturing method (S10) of manufacturing method 1 of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] First, the background of the present invention will be described. Gypsum boards are used in large quantities mainly as interior materials for walls and ceilings of buildings. Therefore, gypsum boards discharged as waste materials (hereinafter, waste gypsum boards) are generated at new construction sites and demolition sites of old buildings. New construction waste gypsum boards are collected by gypsum board manufacturers and reused as board raw materials, while demolition waste gypsum boards are mostly disposed of in landfills, although some are recycled as cement raw materials or soil improvement materials. Since it is expected that the number of old buildings will increase in the future, there is a problem of securing final disposal sites, and recycling of waste gypsum boards is an important issue. Therefore, according to an embodiment of the present invention, gypsum (dihydrate gypsum) separated from waste gypsum boards is actively used and recycled as a ground improvement material, so that waste gypsum boards can be properly processed.

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the illustrated examples. FIG. 1 is a diagram illustrating a manufacturing method (S10) in this embodiment. As shown in FIG. 1, the method for producing a solidification material in this embodiment is to produce a solidification material for ground improvement by reusing gypsum G separated from demolition waste gypsum boards.

[0014] In step 100 (S100), a worker separates the demolition waste gypsum board into paper and gypsum G. Then, the worker crushes the separated gypsum G. The separated gypsum G is gypsum dihydrate. Note that the step of S100 may be performed by an intermediate processor, and in this case, this step can be omitted and the process proceeds to step S102.

[0015] In step 102 (S102), the worker heats the gypsum separated from the waste gypsum board at a temperature and for a time period that will turn it into gypsum hemihydrate. The worker heats the gypsum G in a heating and drying furnace at 110°C to 150°C for 20 minutes to 60 minutes. In the process of this example, the worker heats the gypsum G at 150°C for 20 minutes. The heated gypsum G turns from gypsum dihydrate into gypsum hemihydrate (calcined gypsum).

[0016] In step 104 (S104), the worker uses a magnetic separator to separate magnetic matter (e.g., metal waste such as stapler cores) that may remain in the gypsum G that has become hemihydrate from other matter, and removes the magnetic matter from the gypsum G.

[0017] In step 106 (S106), the worker uses a crusher to crush the gypsum G that has become hemihydrate gypsum to an arbitrary particle size. Specifically, the worker crushes the gypsum G to a degree of coarse to medium crushing. The worker crushes the gypsum G to a particle size of 3 mm or less, specifically, to a particle size of 0.8 mm or less. In this example, the gypsum G is crushed to particles with a particle size of 0.4 mm to 0.6 mm. As a result, the worker obtains gypsum G that can be used for recycling.

[0018] In step 108 (S108), the worker adjusts the moisture content of the admixture to be mixed with the gypsum G. The admixture is, for example, purified water sludge, cement, and lime (quicklime or slaked lime). The lime in this example is quicklime. The worker prepares purified water sludge, cement, and quicklime, which are powdered at room temperature and have a moisture content adjusted to less than 11% so that the moisture contained in the quicklime and purified water sludge does not cause a hydration reaction of the gypsum. Specifically, when adjusting the moisture content of the purified water sludge, the worker heats it with superheated steam at 100°C or higher and 150°C or lower for 10 minutes to 30 minutes, specifically, for 20 minutes with superheated steam at 120°C, to obtain purified water sludge with a moisture content of the 10% range. The worker also dries the cement and quicklime using a known drying method to obtain cement and quicklime with a moisture content of the 10% range.

[0019] In step 110 (S110), the worker uses a weighing machine to appropriately select and weigh gypsum G, quicklime, cement, and purified water sludge depending on the type of solidification material to be produced. When producing a lime-based solidification material, the worker weighs gypsum G, purified water sludge, and quicklime, and when producing a cement-based solidification material, the worker weighs gypsum G, purified water sludge, and cement. Also, when producing a gypsum-based solidification material, the worker weighs gypsum G and purified water sludge.

[0020] In step 112 (S112), the worker mixes gypsum G with a mixture according to the type of solidification material to be produced. Specifically, when producing a lime-based solidification material, gypsum G, purified water sludge, and quicklime are mixed, and when producing a cement-based solidification material, gypsum G, purified water sludge, and cement are mixed. Also, when producing a gypsum-based solidification material, gypsum G and purified water sludge are mixed. In this way, the worker obtains a solidification material. For example, the worker mixes gypsum G, purified water sludge, quicklime, or cement so that the gypsum G that has become hemihydrate gypsum is 45 weight percent or more and 65 weight percent or less, and the purified water sludge in a dried state is 5 weight percent or more. Specifically, the worker mixes gypsum G with a weight ratio of 48% or more and 52% or less, purified water sludge with a weight ratio of 8% to 12%, and cement or quicklime with a weight ratio of 38% or more and 42% or less. By including the purified water sludge in the above ratio, it is possible to inhibit the generation or elution of hydrogen sulfide and fluorine from the hemihydrate gypsum.

[0021] In step 114 (S114), the worker puts the solidification material, which is a mixture of gypsum G and the admixture, into a transport container and bags it. In this example, the solidification material, which is at 60°C or less, specifically, between 50°C and 60°C, is bagged and packed in a flexible container bag (hereinafter, FIBC). The FIBC is made by weaving polypropylene fiber material into a bag shape and disposing polyethylene material on the inside. For example, the inner surface of the woven fabric may be laminated with a polyethylene film, or an inner bag made of polyethylene may be provided.

[0022] In step 116 (S116), in an environment where contact with outside air is limited, the worker allows the solidification material placed in the FIBC bag to radiate heat at 50°C to 60°C until it reaches room temperature. In this process, inside the building, the worker cools the solidification material packed in the FIBC bag to room temperature with the bag opening open. After confirming that the solidification material has reached room temperature, the worker closes the bag opening to complete the packaging.

[0023] As described above, according to the manufacturing method of the solidification material in this embodiment, a relatively large amount of hemihydrate gypsum can be utilized, so that the gypsum contained in the waste gypsum board can be reused. In addition, by incorporating purified water sludge into the solidification material, it is possible to suppress the fluorine eluted from the hemihydrate gypsum while also reusing the purified water sludge. This can promote the recycling of gypsum, purified water sludge, and the like that would otherwise be treated as industrial waste.

Claims

1. A heating step of heating the gypsum separated from the waste gypsum board at a temperature and for a time period in which the gypsum becomes hemihydrate; A mixing step of mixing the hemihydrate gypsum produced by the heating step with an admixture in an amount corresponding to the amount of the hemihydrate gypsum; a step of introducing the hemihydrate gypsum and the mixed material mixed in the mixing step into a transport container; A method for producing a solidification material having the above structure.

2. A heat dissipation process in which the hemihydrate gypsum and the mixed material put into the transport container are dissipated in an environment in which contact with the outside air is limited. The method for producing a solidifying material according to claim 1 , further comprising:

3. In the mixing step, the hemihydrate gypsum, the purified water sludge, and quicklime, slaked lime, or cement are mixed so that the hemihydrate gypsum is 45 weight percent or more and 65 weight percent or more, and the dried purified water sludge is 5 weight percent or more. A method for producing the solidifying material according to claim 2.

4. The transport container includes an inner polyethylene material, In the charging step, the mixed hemihydrate gypsum and the admixture are charged into the transport container so as to be covered with a polyethylene material. A method for producing the solidifying material according to claim 3.

5. A moisture content adjustment step of adjusting the moisture content of the purified water sludge using superheated steam so that the moisture content is less than 11%. and In the mixing step, hemihydrate gypsum is mixed with a mixture containing purified water sludge whose water content has been adjusted in the water content adjusting step. A method for producing the solidifying material according to claim 4.

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