Solidification material and manufacturing method thereof

Abstract

To effectively utilize disposed gypsum boards.SOLUTION: A solidification material includes 45 wt.% or over and 65 wt.% or under of gypsum hemihydrate, 5 wt.% or over of a fine-grained soil, quicklime, and hydrated lime or cement. Preferably, the gypsum hemihydrate is those derived from disposed gypsum boards, and the fine-grained soil comprises a dry-condition water purification sludge. By these, in current situations where recycling of disposed gypsum boards are not advancing, relatively large amounts of gypsum hemihydrate can be reused as a part of a solidification material, and increase in recycling rate of gypsum boards can be expected. Also, water purification sludge can be reused.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] For example, Patent Document 1 discloses a method for recycling waste gypsum board, in which both sides of a gypsum core material are covered with base paper for board, by crushing and drying the entire board while it remains integrated with the core material without separating it from the core material, and using the resulting board as an improver for sludge. Patent Document 2 also describes a soil granulation additive containing 100 parts by mass of inorganic powder and 0.01 to 50 parts by mass of a thickening material, wherein the inorganic powder preferably has a Blaine specific surface area of ​​1500 g / cm. 2 The present invention also discloses a soil granulation additive that is one or more selected from calcium carbonate powder, hemihydrate gypsum, anhydrous gypsum, bentonite, zeolite, silica powder, coal ash, shale powder, sepiolite, activated carbon, activated clay, diatomaceous earth, and dolomite. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-161895 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-100409 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to make effective use of gypsum, and in particular to make effective use of discarded gypsum board. [Means for solving the problem]

[0005] The solidification material of the present invention contains 45 to 65 weight percent of gypsum hemihydrate, 5 weight percent or more of fine soil, and quicklime or cement. For example, given the current situation where recycling of discarded gypsum boards is not progressing, reusing a relatively large amount of gypsum hemihydrate as part of the solidification material is expected to improve the recycling rate of gypsum boards.

[0006] Preferably, the hemihydrate gypsum is derived from gypsum board.

[0007] Preferably, the gypsum hemihydrate is derived from discarded gypsum boards, and the fine-grained soil is dried water purification sludge, which allows for the reuse of not only discarded gypsum boards but also water purification sludge.

[0008] Preferably, the weight ratio of the hemihydrate gypsum is 48% or more and 52% or less, the weight ratio of the purified water sludge is 8% or more and 12% or less, and the weight ratio of the quicklime or the cement is 38% or more and 42% or less.

[0009] The method for producing a solidification material according to the present invention comprises the steps of producing gypsum hemihydrate by crushing, separating and heating discarded gypsum boards, and mixing the produced gypsum hemihydrate with the purified water sludge and quicklime 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. [Effects of the Invention]

[0010] According to the present invention, discarded gypsum boards can be effectively utilized. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described. The solidification material of this embodiment contains 45 to 65 weight percent of gypsum hemihydrate, 5 weight percent or more of fine-grained soil, and quicklime or cement. More specifically, the weight ratio of the gypsum hemihydrate is 48 to 52 percent, the weight ratio of the fine-grained soil is 8 to 12 percent, and the weight ratio of the quicklime or cement is 38 to 42 percent.

[0012] The gypsum hemihydrate contained in the solidification material is derived from gypsum board. More specifically, the gypsum hemihydrate is obtained by crushing and separating discarded gypsum board, and then heating the gypsum dihydrate in a drying furnace at 100 to 120°C for 24 hours. The content of gypsum hemihydrate in the solidifying material is 45% to 65% by weight, more specifically, 48% to 52% by weight.

[0013] The fine-grained soil contained in the solidification material is, for example, dried purified water sludge. The content of purified water sludge in the solidification material is 5% or more by weight. More specifically, it is 8% to 12% by weight. By including purified water sludge in the above ratio, it is possible to suppress the generation or elution of hydrogen sulfide and fluorine from the hemihydrate gypsum.

[0014] The content of quicklime or cement in the solidification material is 38% to 42% by weight. That is, the solidification material of this embodiment may be a lime-based solidification material to which quicklime is added, or a cement-based solidification material to which cement is added. Note that slaked lime may be contained instead of quicklime.

[0015] [Solidification material manufacturing method] The method for producing the solidification material in this embodiment includes a first step of producing gypsum hemihydrate by crushing, separating, and heating discarded gypsum board, and a second step of mixing the produced gypsum hemihydrate, purified water sludge, and quicklime 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. In the first step, discarded gypsum board is crushed and separated to obtain gypsum dihydrate. The obtained gypsum dihydrate is converted into gypsum hemihydrate by heating in a drying oven at 100°C to 120°C for 6 hours or more. For example, gypsum hemihydrate can be obtained from gypsum dihydrate by heating in a drying oven at about 110°C for 24 hours. Note that the heating conditions may be such that the temperature of the drying oven is about 130°C and the heating time is shorter. In the second step, more specifically, 50% by weight of hemihydrate gypsum, 40% by weight of quicklime, and 10% by weight of dried purified water sludge are mixed to obtain the solidification material.

[0016] As described above, the solidification material of this embodiment makes it possible to utilize a relatively large amount of gypsum hemihydrate while suppressing the elution of hydrogen sulfide and fluorine from the gypsum hemihydrate, thereby promoting the recycling of discarded gypsum boards. Furthermore, the added hemihydrate gypsum does not simply act as a soil substitute (bulking material) to reduce the moisture content, but also contributes to chemical solidification through a hydration reaction with the soil particles. By mixing a relatively large amount of hemihydrate gypsum and lime, a unique strength can be expected.

Claims

1. A composition comprising: a weight ratio of 48% to 52% hemihydrate gypsum; Dried water purification sludge and Quicklime, slaked lime or cement Including, The hemihydrate gypsum is derived from discarded gypsum board, The purified water sludge has a weight ratio of 8% to 12%. The quicklime, slaked lime, or cement is 38% or more and 42% or less by weight. Solidification material.

2. A process of producing gypsum hemihydrate by crushing, separating, and heating the discarded gypsum board; mixing the generated hemihydrate, the purified water sludge, and the quicklime, the slaked lime, or the cement so that the generated hemihydrate is 48 weight percent or more and 52 weight percent, the dried purified water sludge is 8 weight percent or more and 12 weight percent or less, and the quicklime, the slaked lime, or the cement is 38 weight percent or more and 42 weight percent or less; A method for manufacturing a solidification material having the above structure.