JPH10296224A - Method for utilizing waste gypsum board material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively and economically reuse a waste material generated at a construction site by sorting the waste material into a gypsum board base paper and gypsum or shredding, crushing the waste material without sorting it out, and using the crushed pieces as a raw material for a material to be manufactured using a large amount of water when it is molded. SOLUTION: A waste material composed of a gypsum base paper sticking to part of a gypsum core is sorted out into a gypsum board base paper part and a gypsum part, or is shredded and crushed without sorting at all to obtain a mixture of the gypsum and a shredded paper material. This mixture is effectively reused as a raw material for a material to be manufactured using a large amount of water when molding a calcium silicide board. For another use application, a mixture of the gypsum and the shredded paper material is heated to obtain the gypsum as plaster of Paris and this plaster of Paris is used as a substitute for a raw material plaster of Paris when a variety of materials are molded using a large amount of water. Another application of this plaster of Paris is as a raw material for blast finishing. Thus it is possible to economically and effectively reuse the waste material generated at a construction site, a manufacturing mill or other facilities.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for pulverizing and / or pulverizing gypsum board waste material to produce gypsum as it is or as hemihydrate gypsum. The present invention relates to a method for using a waste gypsum board, which is used as a raw material of a material produced by using the method or as a raw material of a spraying method.

[0002]

2. Description of the Related Art In recent years, gypsum boards are widely used as building materials because gypsum has fire resistance, sound insulation and the like and is economical. Such a gypsum board has a plate-like structure in which a gypsum-based core material is covered with a gypsum board base paper, and a gypsum board having a product thickness of 12 mm has a plaster amount of about 93% by weight (hereinafter simply referred to as%). Abbreviated), and the base paper amount is about 7%. This gypsum board is used everywhere in a building, and at a construction site, waste (hereinafter, referred to as waste material) such as remaining offcuts cut in accordance with the dimensions of a used portion is generated. It is said that the amount of waste material generated is 10-15% of the used amount. Considering that the annual use amount of gypsum board is 5 million tons, about 500,000 to 750,000 tons of waste material is generated as industrial waste. Approximately 1 million tons per year, together with waste materials generated during manufacturing, are disposed of by landfills, as with other industrial waste. On the other hand, the disposal of industrial waste by landfill is socially problematic due to environmental and landfill shortages and other reasons, and the "Law on the Use of Recycled Resources (Recycling Law)" was enacted in April 1991. It was promulgated in October, and came into effect in October of the same year. Some of the other industrial wastes are already under the laws and regulations that are basically borne by the manufacturer, and methods of treating industrial wastes that can be effectively reused are being developed. Under such circumstances, waste materials of gypsum boards generated from construction sites and the like are no exception, and there is a strong demand for the development of a treatment method that can be effectively used without disposing the waste materials as industrial waste. As a method for solving these problems, a method for separating and recovering gypsum and gypsum board base paper from waste materials, is disclosed in Japanese Patent Application Laid-Open No. 06-14263.
3. JP-A-06-142638 has been proposed. However, there is a limit to the separation, and it is inevitable that they mix with each other.Recycling to gypsum board requires a large amount of water to obtain a certain mixture softness and consistency due to the mixed paper. In order to reduce the physical properties of the product, only limited reuse is required. on the other hand,
The gypsum mixed into the paper hinders effective use, and at the time of incineration, SOx is generated. Separation is accompanied by difficulties such as heavy use of energy and complicated processing, and reuse is extremely limited. As a result, many waste materials are currently disposed of in landfills.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a construction site,
It is an object of the present invention to provide a method for effectively and economically recycling waste materials generated from a manufacturing plant or the like.

[0004]

SUMMARY OF THE INVENTION According to the present invention, waste material is separated into gypsum board base paper and gypsum, or crushed and pulverized without separation, and a mixture of the gypsum and the crushed paper is used as it is or calcined gypsum. After that, when used as a raw material for paper gypsum board, silica gel plate, etc., when used simply by replacing with gypsum raw material, compared with the conventional gypsum itself, good properties in various points, especially It has been found that a product having good bending strength can be obtained, and that powder loss during papermaking is extremely small, thereby achieving a marked improvement in production efficiency. In addition, when used in place of plaster of Paris as a raw material of a spraying material for fire-resistant coatings such as steel frames, construction can be performed without impairing workability, and the obtained fire-resistant coatings are also found to have good properties. Was. The present invention has been made based on these findings. That is, the present invention separates the waste material having the gypsum base paper adhered to at least a part of the gypsum core into the gypsum board base paper portion and the gypsum portion, or without any separation.
Crushing, crushing, a method of effectively reusing the mixture of gypsum and paper crushed material as a raw material of a material produced using a large amount of water at the time of molding, such as a silica plate, and heating the mixture. The present invention also provides a method for reusing gypsum from calcined gypsum, as a raw material for various materials that are similarly molded using a large amount of water as a substitute for calcined gypsum, and as a raw material for spraying materials. The waste material on which the method of the present invention is performed is generally in a form in which a gypsum core is covered with gypsum board base paper (hereinafter referred to as base paper). The shape is plate-like, massive, or powdery. These waste materials may be crushed as they are, in which the gypsum portion and the base paper portion are separated, or may be crushed after the base paper portion is separated and removed to some extent. In particular, in the case of a plate or lump, it is preferable to place a crushing step before the crushing step in order to efficiently perform the subsequent crushing step. The degree of the crushing may be such that the gypsum is adhered to the adhesive surface of the base paper with the gypsum core, or that only part of the gypsum is in close contact. It is preferably 10 mm or less.
Such a crushed material is sent to the heating step as it is, and after the gypsum contained therein is made into hemihydrate gypsum, it can be crushed afterwards, or conversely, after the crushing and heating step, the gypsum in the mixture is made into calcined gypsum Is also possible. When used as a substitute for gypsum, the mixed powder obtained by pulverizing the crushed material is used as a raw material as it is.

[0005] The above-mentioned pulverizing method may be based on ordinary compression, impact, shear, friction and cutting, and is not particularly limited. The method for heating the mixture of gypsum and base paper in the heating step of the present invention may be direct heating using a rotary dryer or indirect heating using a vertical kiln. The heating temperature may be any temperature at which gypsum can be converted into hemihydrate gypsum or a form containing partially soluble anhydrous gypsum in gypsum (calculated gypsum), and a range of 100 to 200 ° C. is exemplified. The preferred temperature range is 130-190C. In the above-mentioned temperature range, it is preferable to heat usually for 0.5 to 3 hours, preferably for 1 to 2 hours. The pulverized mixture is used as is or through a heating process, as a mixture of hemihydrate gypsum and crushed base paper, mixed with a large amount of water in the molding process, such as papermaking gypsum plate and silica plate, and manufactured by processes such as papermaking It can be effectively used as a raw material of a material to be formed or as a raw material of a spray material such as a fireproof coating. Next, the present invention will be described in more detail with reference to examples.

[0006]

【Example】

Example 1 Waste gypsum board (waste material mainly composed of offcuts of a gypsum board having a thickness of 12 mm) was crushed by a crusher (shaft shredder manufactured by Kubota Corporation) and sieved with a 10 mm sieve.
The portion below the sieve was a crushed product. 50 kg of this crushed product was fired by a vertical kiln-type gypsum heating device, and the gypsum in the mixture was converted into gypsum [powder (A)]. Heating temperature and time are 170 ℃, 6
It was 0 minutes. The fired powder is pulverized with a ball mill and 1 mm
The powder was passed through an eye sieve [powder (A)]. All the mixtures were in powder form, and the powder (A) was a mixture of calcined gypsum mainly composed of hemihydrate gypsum and crushed paper, and was used as a raw material for a papermaking fiber gypsum board having the following composition. For comparison, the composition is shown in Table 1 together with a commercially available hemihydrate gypsum powder, and the properties are shown in Table 2. The powdered raw material was mixed with powder and added with water to form a slurry having a concentration of 5%. After papermaking and lamination by the usual method,
After being pressed, cured, and passed through a dryer at 130 ° C., the product was subjected to a property test. At the time of papermaking, a 60-mesh, 30-second drainage rate and powder loss were measured. The results are shown in Table-2. Material Gypsum; Plaster for board of JIS A6904 Calcium carbonate powder; Heavy tankal clay; Mach 70 (from Tsuruga) Pulp; Gold river pulp (beaten to 150cc freeness) Tartaric acid; From the results in Table-2, the bending strength was corrected for density a
It is determined that the value of / ρ2 is about 6% higher than the comparative example. Example 2 Gypsum board waste material (waste material mainly composed of offcuts of 9.5 mm thick gypsum board) was crushed by a crusher (manufactured by Kubota Co., Ltd., shaft shredder) and sieved with a 10 mm sieve. Was used as a crushed product. 50 kg of the crushed product was pulverized with a ball mill to obtain a powder (B) that passed through a 1 mm sieve.
Powder (B) is a mixture of gypsum dihydrate and crushed paper,
It was used as a raw material for a silica plate having the following composition. For comparison, Table 3 shows the composition together with Comparative Example 2 in which gypsum powder was blended.
Fig. 4 shows its properties. Water was added to the mixed powder, mixed with the powder, and then a slurry having a concentration of 5% was obtained. After papermaking and lamination, pressing, autoclave treatment at 180 ° C. for 10 hours according to a standard method, and then subjected to a property test. Materials Slaked lime; Chichibu lime industrial clay; Mach 70 (from Tsuruga) Ordinary Portland cement; Chichibu Onoda Co., Ltd. gypsum; Exhausted plaster (Comris) Perlite; Processing No. 2 (Mitsui Metals) Pulp; (Beat to 150cc freeness) The flexural strength is almost the same as the comparative example or slightly higher (about 3%) when the bulk specific gravity is corrected. The powder loss is 0.16 points, that is, about 20% less than that of the comparative example, which is extremely preferable in terms of production efficiency. Further, it is also conceivable to reduce the amount of coagulant added for circulating reuse of water. Example 3 Powder A of Example 1 was used as a raw material for a sprayed refractory coating having the following composition. For comparison, the formulation is shown in Table-5 together with the commercially available hemihydrate gypsum powder, and the properties are shown in Table-6. The mixture in Table 5 was dry-mixed with a mortar mixer, a predetermined amount of water was added, and the mixture was stirred for 2 minutes. The slurry is pressure-fed by a piston type pump using a pressure-resistant rubber hose having an inner diameter of 35 mm and a length of 20 m, and 18 liters per minute to a spray nozzle, and 400 × 200 × 8 × 13 mm 2.5 m long.
Spray the mold steel and leave it as it is. Two weeks later, the coating was dried at 40 ° C. for 3 weeks, and the sprayed refractory coating was observed for cracks. This was further placed in a heating furnace, and a fire resistance test was performed according to JIS A1304, and the fire resistance time and the compressive strength after heating were measured. Material Plaster of plaster; Plaster for board of JIS A6904 Wood fiber; Jet fiber made of Jujo wood Expanded polystyrene; Particle size 2.2 mm or less, bulk specific gravity x 0.02

Although the reasons for these effects, improvement in bending strength, reduction in powder loss, and improvement in fire resistance are not clear, it has been conventionally difficult to separate gypsum and paper in an attempt to recycle waste materials. Judging from that, in the crushed waste material, the gypsum and the crushed paper are still entangled even after crushing and crushing, improving the strength, and improving the trapping efficiency of papermaking, that is, reducing powder loss, It is considered that this has led to the improvement of the structure of the refractory coating.

[0008]

According to the present invention, waste materials generated at construction sites, manufacturing plants, and the like are mixed with a large amount of water in various products, particularly in molding, and materials produced by a process such as papermaking, fire-resistant coating, etc. It can be reused as a raw material for spraying materials, and can be effectively used as a raw material for gypsum plasterboard, siliceous board, gypsum-based refractory coatings, etc. it can.

Claims (3)

[Claims] (1) A waste gypsum board is separated into gypsum board base paper and gypsum, or is used as a raw material of a material produced by using a large amount of water at the time of crushing, crushing and molding without separation. A method for recycling waste gypsum board. 2. A recycling method according to claim 1, wherein a heating step is added before or after the crushing and pulverizing steps, and the gypsum in the mixture is calcined gypsum. 3. The waste gypsum board is separated into gypsum board base paper and gypsum or, without separation, crushed, crushed, and heated before or after the crushing and crushing steps to add gypsum in the mixture. A method for recycling waste gypsum board, wherein the method is used in a process of giving a shape by spraying the granules made of calcined gypsum.