Mortar material manufacturing method

Abstract

To provide a recycled aggregate using a bottom ash including harmful substances such as arsenic, boron, and selenium, excluded by combustion of a circulating fluidized layer boiler, with the harmful components having been insolubilized.SOLUTION: A surface of a bottom ash 2 including harmful substances such as arsenic, boron, and selenium is dampened and is mixed with a covering material including a cement. A coating layer 3 formed by curing the covering material is formed on the surface of the bottom ash 2, and the bottom ash 2 is insolubilized and can be used as a recycled aggregate 1.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a recycled aggregate containing bottom ash removed during the operation of a circulating fluidized bed boiler, a mortar material containing this recycled aggregate, and methods for producing the recycled aggregate and the mortar material. [Background technology]

[0002] A circulating fluidized bed boiler is a type of boiler specified in JIS B 0126:2018 (Thermal Power Generation Terminology - Boilers and Auxiliary Equipment), and is also called a circulating fluidized bed boiler. Because it uses solid fuel for efficient combustion (operation), it is increasingly being put to practical use in biomass power generation and other applications. A circulating fluidized bed boiler fills the combustion chamber with particulate matter as a fluidized bed, and high-pressure air is pumped in from below the boiler to fluidize the particulate matter and agitate the solid fuel, biomass, while burning it, thereby increasing the efficiency of combustion and power generation.

[0003] The particulate matter in the fluidized bed rises, swirling within the combustion chamber along with the combustion gases produced by the biomass combustion, and is separated into particulate matter and ash (fly ash) by a centrifuge. The separated particulate matter is classified by particle size, and large particles (bottom ash) that could damage the combustion chamber are removed and reused as particulate matter in the fluidized bed.

[0004] The removed bottom ash cannot be used as particulate matter in the fluidized bed, so it is required to be reused for other purposes. As an example of reusing bottom ash, Patent Document 1 describes a cement raw material that contains bottom ash discharged from a circulating fluidized bed boiler and sludge. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-313643 Summary of the Invention [Problem to be solved by the invention]

[0006] Bottom ash removed by combustion in a circulating fluidized bed boiler contains concentrated traces of harmful components found in biomass, such as arsenic, boron, and selenium. However, conventional cement raw materials made from recycled bottom ash have not taken into consideration the presence of these harmful components, and there has been a problem in that harmful components may leak out over the long term from compacts formed from this cement raw material.

[0007] The present invention aims to solve the above-mentioned problems and to provide recycled aggregate in which harmful components such as arsenic, boron, and selenium are insolubilized, using bottom ash removed by combustion in a circulating fluidized bed boiler. [Means for solving the problem]

[0008] The recycled aggregate according to the present invention is a mixture of bottom ash removed by the operation of a circulating fluidized bed boiler using particulate matter as a fluidizing medium, a coating layer formed by hardening a coating material containing cement and coating the bottom ash; The present invention is characterized in that it is composed of:

[0009] According to the recycled aggregate of the present invention, the bottom ash is coated with a coating layer formed by hardening a coating material containing cement, thereby making it possible to insolubilize harmful components contained in the bottom ash, such as arsenic, boron, and selenium.

[0010] The mortar material according to the present invention is characterized by containing the above-mentioned recycled aggregate and a hydraulic material.

[0011] According to the mortar material of the present invention, recycled aggregate in which harmful components have been insolubilized can be used as the mortar material.

[0012] Furthermore, the method for producing recycled aggregate according to the present invention is characterized by comprising a first step of wetting the surface of the bottom ash, and a second step of mixing the wetted bottom ash with the coating material containing the cement to provide the coating layer on the bottom ash.

[0013] According to the method for producing recycled aggregate of the present invention, the bottom ash is coated with a coating layer formed by hardening a coating material containing cement, thereby making it possible to insolubilize harmful components contained in the bottom ash, such as arsenic, boron, and selenium.

[0014] In the above-mentioned method for producing a mortar material, the water content of the bottom ash after the first step may be 0.2 to 10 mass %.

[0015] This makes it possible to insolubilize harmful components in the recycled aggregate.

[0016] Furthermore, the method for producing a mortar material according to the present invention is characterized by comprising a first step of wetting the surface of the bottom ash, a second step of mixing the wetted bottom ash with the coating material containing the cement to prepare a mixture containing the recycled aggregate, and a third step of mixing the mixture with the hydraulic material to prepare a mortar material.

[0017] According to the method for producing a mortar material of the present invention, a mortar material containing recycled aggregate in which harmful components have been insolubilized can be produced. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide recycled aggregate in which harmful components contained in bottom ash, such as arsenic, boron, and selenium, have been insolubilized. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram showing an outline of a circulating fluidized bed boiler. [Figure 2] FIG. 2 is a diagram showing the structure of recycled aggregate. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the recycled aggregate 1 according to the present invention will be described. The meanings of the terms used in this specification and claims are as follows.

[0021] "%" (in the formulation unit) means "mass %" unless otherwise specified. "Average particle size" means the median diameter (d50) determined using a JIS standard sieve (JIS Z 8801-1:2019).

[0022] The recycled aggregate 1 of this embodiment is formed by using bottom ash 2, which contains harmful substances such as arsenic, boron, and selenium and is removed by combustion in a circulating fluidized bed boiler 100, as a core, wetting the surface of the bottom ash 2, and mixing the wetted surface bottom ash 2 with a coating material (sometimes simply referred to as coating material) containing cement. The coating material hardens on the surface of the bottom ash 2, forming a coating layer 3 that covers the surface of the bottom ash 2, and therefore the recycled aggregate 1 has harmful substances insolubilized.

[0023] The circulating fluidized bed boiler 100 is a boiler in which particulate matter 101, some of which will later become bottom ash 2, is filled as a fluidized bed in the combustion chamber of the circulating fluidized bed boiler 100, and high-pressure air 105 is sent from below the boiler to fluidize the particulate matter 101 and burn the solid fuel while stirring it. Because burning the solid fuel while stirring it can increase the efficiency of combustion, the circulating fluidized bed boiler 100 is increasingly being put to practical use in applications where heat generated by combustion is used to generate power.

[0024] The particulate matter 101, part of which becomes the bottom ash 2, is preferably made of a hard material in order to agitate the solid fuel, and can be made of, for example, silica sand, kansui sand, serben (crushed sanitary ware), blast furnace slag, etc. Among these, silica sand or kansui sand, which are easily available, can be preferably used, and silica sand, which has high hardness and can extend the use cycle as particulate matter 101, can be more preferably used.

[0025] Bottom ash 2 is removed from particulate matter 101 as a fluidized bed that agitates solid fuel because its particle size makes it unsuitable for use. Specifically, bottom ash 2 is a particle on the larger particle size side of the particle size distribution of particulate matter 101. The flow of larger particles may damage the inside of the circulating fluidized bed boiler 100, and so it is removed. The bottom ash 2 is separated by the particulate matter 101 flowing through the circulating fluidized bed boiler 100 during operation, flowing from the exhaust port 103 to the centrifuge 104, where the larger particles are classified based on their particle size and discharged as bottom ash 2. The particle size of bottom ash 2 that may damage the combustion chamber varies depending on the equipment of the circulating fluidized bed boiler 100, but is generally 250 μm or larger, more preferably 500 μm or larger, and even more preferably 600 μm or larger. It should be noted that, since particles of non-standard size are removed from the particulate matter 101 at the shipping source, it is believed that the particle diameter of the bottom ash 2 will not exceed 1000 μm.

[0026] The solid fuel used in the circulating fluidized bed boiler 100 can be any solid fuel, but it is preferable to use biomass fuel 102, which has few other uses. Examples of solid biomass fuel 102 that can be used include wood chips, grasses and inedible parts of crops, inedible parts of meat and livestock, food waste, animal carcasses, coal, manure, and combinations of these. Among these, plant-derived wood chips and / or grasses and inedible parts of crops are preferred because they are carbon neutral because the plants and animals that form the source of biomass fuel 102 absorb carbon dioxide during their growth. Furthermore, coal can be added to the wood chips and / or grasses and inedible parts of crops to increase the thermal power of combustion.

[0027] Biomass fuel 102 is formed by accumulating harmful components such as arsenic, boron, and selenium, which are present in trace amounts in ecosystems, during the growth process of plants and animals before becoming fuel. Therefore, when biomass fuel 102 is used as fuel for a circulating fluidized bed boiler 100, it releases these harmful components into the boiler 100. As a result, the harmful components adhere to the particulate matter 101 that stirs the biomass fuel 102, and also to the bottom ash 2 used as the core of the recycled aggregate 1. When the bottom ash 2 is reused, the harmful components that adhere to the bottom ash 2 may leach out from the bottom ash 2 over time, potentially causing adverse effects on the surrounding ecosystem. For this reason, when reusing the bottom ash 2, the bottom ash 2 is treated to insolubilize the harmful components using a coating material containing cement, as described below.

[0028] A cement-containing coating material is a coating material that coats the surface of bottom ash 2 to insolubilize harmful components. Because cement-containing coating materials contain cement, when they are mixed with moistened bottom ash 2, the calcium content of the cement dissolves in the moisture on the surface of the bottom ash 2, producing cement hydrate crystals that are insoluble in water. The cement hydrates that are produced harden to fill the voids on the surface of the bottom ash 2, coating the bottom ash 2 and blocking it, along with the harmful components. Because cement hydrates are insoluble in water, they can insolubilize harmful components that have adhered to the bottom ash 2.

[0029] Any cement that produces cement hydrate can be used, including Portland cement specified in JIS R 5210:2019 (ordinary Portland cement, early-strength Portland cement, extra-early-strength Portland cement, moderate-heat Portland cement, low-heat Portland cement, sulfate-resistant Portland cement, ordinary Portland cement (low alkali type), early-strength Portland cement (low alkali type), extra-early-strength Portland cement (low alkali type), moderate-heat Portland cement (low alkali type), low-heat Portland cement (low alkali type), sulfate-resistant Portland cement (low alkali type)), or cement that does not fall under JIS but is equivalent to JIS R 5210:2019 (for example, extra-fast-hardening cement, foreign-made Portland cement, etc.). Portland cement also includes white Portland cement, which is made white by reducing the black components (chromium (Cr2O3), manganese (Mn2O3), iron (Fe2O3), etc.) of Portland cement. Of these cements, ordinary Portland cement or high-early-strength Portland cement is preferred because it is easily available and inexpensive.

[0030] In addition to cement, the cement-containing coating material may contain, as needed, aggregate as a bulking agent, a water-retaining agent to prevent the cement from drying out, a pigment to impart color, a chelating agent to sequester metal ions such as calcium ions and iron ions, and the like.

[0031] The recycled aggregate 1 of this embodiment can be produced using a mixer such as a paddle mixer, a Nauta mixer, a ribbon mixer, a conical screw mixer, or a Henschel mixer, and the raw materials are fed into the mixer by a transfer device capable of transporting powder, such as a belt conveyor. The transfer device that feeds the bottom ash 2 is equipped with a sprinkler to moisten the bottom ash 2.

[0032] The manufacturing method of the recycled aggregate 1 of the embodiment comprises a first step of wetting the surface of the bottom ash 2, and a second step of mixing the wetted bottom ash 2 with a coating material containing cement to coat the bottom ash 2 with the coating material.

[0033] In the first step of wetting the surface of the bottom ash 2, water is sprayed onto the bottom ash 2 while it is being transported using a water sprayer attached to the transporter. The water content (external ratio) of the bottom ash 2 after spraying is preferably 0.2 to 10 mass% relative to the mass of the bottom ash 2. This is because harmful components attached to the bottom ash 2 can be suitably insolubilized by being coated with a coating material containing cement, as described below. If the water content is less than 0.2 mass% relative to the mass of the bottom ash 2, the cement hydrate may not be able to fill all of the voids on the surface of the bottom ash 2, and the harmful components may not be insolubilized. On the other hand, if the water content exceeds 10 mass%, the excess water content may harden (hydrate) even coating materials that do not contribute to coating the bottom ash 2, which may be uneconomical. More preferably, the water content relative to the mass of the bottom ash 2 is 0.3 to 5 mass%, and even more preferably 0.5 to 2 mass%. The preferred moisture content of the bottom ash 2 is a range determined using multiple types of photom ash 2, but there is a risk that the preferred moisture content of the bottom ash 2 may vary depending on the conditions of the circulating fluidized bed boiler 100 into which the photom ash 2 is discharged and the particulate matter 101. For this reason, it is more preferable to confirm the preferred moisture content of the bottom ash 2 depending on the conditions of the circulating fluidized bed boiler 100 into which the photom ash 2 is discharged and the particulate matter 101.

[0034] In the second step of coating the bottom ash 2 with the coating material, the moistened bottom ash 2 and the coating material are each introduced into a mixer using a transfer device, and the mixer is operated (agitated).

[0035] The mixing ratio of the bottom ash 2 to the coating material is preferably 10 to 600% by mass in terms of the mass of the cement of the coating material relative to the bottom ash 2 (dry state). This is because harmful components attached to the bottom ash 2 can be suitably insolubilized. If the mixing ratio is less than 10% by mass in terms of cement mass, the cement hydrate may not be able to fill all of the voids on the surface of the bottom ash 2, and the harmful components may not be insolubilized. On the other hand, if the mixing ratio exceeds 600% by mass in terms of cement mass, a large proportion of the coating material will not adhere to the bottom ash 2, which may be uneconomical. More preferably, the mixing ratio of the bottom ash 2 to the coating material is 20 to 400% by mass, and even more preferably 40 to 200% by mass in terms of the mass of the cement of the coating material relative to the bottom ash 2 (dry state). Note that the mixing ratio of the bottom ash 2 to the coating material is a mixing ratio, and not all of the coating material will adhere to the bottom ash 2; some coating material will remain unadhered. The presence of the coating material that remains unattached can increase the mixing efficiency of the mixer. The cement of the coating material that adheres to the bottom ash 2 forms cement hydrate with the moisture that moistens the surface of the bottom ash 2, and coats the bottom ash 2. On the other hand, the cement of the coating material that remains unattached to the bottom ash 2 does not undergo a hydration reaction and remains fresh.

[0036] The operation (mixing) of the mixer is sufficient if the bottom ash 2 and the covering material are mixed uniformly to form a uniform mixture, and for example, mixing for about 5 minutes with a uniaxial paddle mixer will achieve sufficient mixing. The bottom ash 2 covered with the covering material can be sieved out from the uniform mixture to obtain the recycled aggregate 1.

[0037] The recycled aggregate 1 produced in this manner can be used as a mortar material in the following embodiment, since the harmful components adhering to the bottom ash 2 have been insolubilized. In addition, since the harmful components have been insolubilized, the recycled aggregate 1 can be used as an aggregate for general mortar or concrete.

[0038] Next, a mortar material according to an embodiment will be described. The mortar material according to the embodiment is a mixture of the recycled aggregate 1 produced as described above, a coating material that does not coat the recycled aggregate 1, and a hydraulic material that hardens by reacting with water, and can be distributed on the market as premixed cement. The mortar material (premixed cement) is used as a plastering material (mortar) by consumers by mixing it with water.

[0039] Hydraulic materials are materials that harden upon reaction with water. Examples of suitable hydraulic materials include the aforementioned cement (Portland cement (JIS R 5210:2019)), blast furnace cement (JIS R 5211:2019), fly ash cement (JIS R 5213:2019), ecocement (JIS R 5214:2019), alumina cement (JIS R 2521:1995), and hydraulic lime. Furthermore, air-hardening materials (lime, gypsum, dolomite plaster, etc.) can also be used as hydraulic materials in embodiments, as long as their strength as mortar materials is not reduced. By using air-hardening materials, for example, it is possible to create a mortar material with a finish similar to plaster.

[0040] The hydraulic material can be added with fillers (aggregates) as extenders or decorative materials, and additives as needed.

[0041] Fillers (aggregates) can be added to mortar materials for at least one of the following purposes: as an extender to reduce the unit cost of the mortar material, as a crack prevention material to prevent cracks caused by expansion and contraction during hardening, or as a design material to add a decorative finish to the mortar material. Examples of fillers that can be used include inorganic powders and granules such as silica sand, kansui sand, serben (crushed sanitary ware), crushed glass, blast furnace slag, and fly ash, as well as organic raw materials such as synthetic resin particles, hollow synthetic resin particles, and synthetic resin fibers.

[0042] As additives that can be added to the mortar material as needed, pigments that impart color to the mortar material, re-emulsified powder resins that prevent the mortar material from shrinking on drying, thickeners that adjust the workability of the mortar material and impart water retention, chelating agents that sequester metal ions such as calcium ions and iron ions, hardening accelerators, retarders, water absorption inhibitors, water repellents, water-reducing agents, fluidizing agents, and the like can be added to the mortar material as needed.

[0043] The manufacturing method of the mortar material of the embodiment comprises a first step of wetting the surface of the bottom ash 2, a second step of mixing the wetted bottom ash 2 with a coating material containing cement to form a mixture containing recycled aggregate 1, and a third step of mixing a hydraulic material with this mixture to form a mortar material.

[0044] The first step of wetting the surface of the bottom ash 2 is the same as the first step in the manufacturing method for recycled aggregate 1. The second step of mixing the wetted bottom ash 2 with a cement-containing coating material to form a mixture containing recycled aggregate 1 is the same as the second step in the manufacturing method for recycled aggregate 1, but this step covers the bottom ash 2 and the coating material until they are uniformly mixed, and does not include a step of sieving the recycled aggregate 1 from the uniform mixture. The mixture after this second step includes the coating material remaining in the mixer without adhering to the bottom ash 2. The cement of the coating material adhering to the bottom ash 2 coats the bottom ash 2 with the moisture that moistens the surface of the bottom ash 2. Meanwhile, the remaining cement of the coating material that is not adhering to the bottom ash 2 remains fresh without undergoing a hydration reaction, and can be hardened (hydrated) by the consumer by mixing it with water along with the hydraulic materials of the mortar material (premix cement).

[0045] In the third step, hydraulic material is added to the mixer after the second step, when the bottom ash 2 and covering material have been uniformly mixed, and the mixer is operated (mixed). The operation (mixing) of the mixer is sufficient if the recycled aggregate 1, the covering material that did not cover the recycled aggregate 1, and the hydraulic material are mixed uniformly; for example, mixing for about 5 minutes with a uniaxial paddle mixer will achieve sufficient mixing. A mortar material can be obtained by mixing.

[0046] The content of bottom ash 2 in the mortar material is preferably 3 to 80% by mass. This is because the bottom ash 2 can be used as a mortar material while being utilized as recycled aggregate 1. If the content of bottom ash 2 in the mortar material is less than 3% by mass, the bottom ash 2 is not utilized effectively, and considering the effort required for the first and second steps, it may be uneconomical. On the other hand, if the content exceeds 80% by mass, the content of cement as a binder becomes relatively low, and the mortar material may not be usable as a mortar material. More preferably, the content of bottom ash 2 in the mortar material is 5 to 75% by mass, and even more preferably 10 to 50% by mass.

[0047] The mortar material (premixed cement) produced in this manner allows the bottom ash 2 to be used effectively and safely because the harmful components are insolubilized. The produced mortar material can be distributed to the market as premixed cement, but it is preferable to allow it to cure (set at rest) for about one day after production. This is because it increases the strength of the cement hydrate formed from the cement in the second step and ensures the insolubilization of the harmful components. The mortar material (premixed cement) can be used as a commercial plastering material by mixing it with water, as well as a home construction material. The mortar material (premixed cement) can be used as a plastering material by adjusting the amount of water added and kneading it so that the mortar's flow value is 150 to 200 mm as measured by flow value measurement (JIS R 5201:2015).

[0048] The recycled aggregate and mortar material of the embodiment can be implemented even if their configurations are changed as follows.

[0049] In the embodiment, the core of the recycled aggregate is bottom ash removed by the operation of a circulating fluidized bed boiler using particulate matter as a fluidizing medium. However, the core of the recycled aggregate can also be particulate matter remaining in the boiler after the operation of the circulating fluidized bed boiler has ended. In this case, the mixing ratio of the particulate matter to the coating material is preferably 20 to 600 mass %, more preferably 30 to 400 mass %, and even more preferably 40 to 200 mass %, in terms of the mass of cement in the coating material relative to the particulate matter (dry state). This allows the particulate matter after the operation of the circulating fluidized bed boiler to be utilized, and harmful substances contained in the particulate matter can be insolubilized.

[0050] Other technical concepts that can be understood from the recycled aggregate and mortar material of the embodiment will be described below.

[0051] In the recycled aggregate, the cement-containing coating material may contain a chelating agent. With this recycled aggregate, the chelating agent sequesters metal ions such as calcium ions and iron ions contained in the cement, thereby suppressing the adverse effects of metal ions on paints, mortars, and other materials that use the recycled aggregate.

[0052] The mortar material may contain a re-emulsified powdered resin as an additive to the hydraulic material, which prevents the mortar material from shrinking upon drying, thereby preventing cracks from occurring in a mortar compact formed from the mortar material.

[0053] The mortar molded body formed from the mortar material of the embodiment can be a mortar molded body formed by hardening a hydraulic material, and the aggregate contained in the mortar molded material can be recycled aggregate, with a core made of bottom ash removed by the operation of a circulating fluidized bed boiler using particulate matter as a fluidizing medium, and a coating layer formed on the surface of the bottom ash by hardening a coating material containing cement. With this mortar molded body, harmful components contained in the bottom ash, such as arsenic, boron, and selenium, are insolubilized by the coating layer and the hydraulic material of the mortar molded body. [Example]

[0054] The present invention will be described in more detail below with reference to examples. Test Examples 1 to 28 are examples. The compositions of recycled aggregate 1 and mortar material and the performance evaluation results are shown in Tables 1 and 2, respectively. The compositions of recycled aggregate 1 and mortar material are shown in mass ratios. In addition, an "x" in the evaluation of the tests for the evaluation items described below means that some of the evaluation items were not met, and does not mean that the example is not included.

[0055] [Table 1]

[0056] [Table 2]

[0057] Some of the names of raw materials in the table are abbreviated. The raw materials used are listed below in parentheses with their general names or raw material names.

[0058] Bottom ash (bottom ash discharged from a biomass power plant in Aichi Prefecture) Water (tap water) Ordinary cement (ordinary Portland cement (JIS R 5210:2019)) High-early-strength Portland cement (JIS R 5210:2019) Ultra-fast hardening cement (Super Cement (manufactured by Denka Co., Ltd.)) Chelating agent (sulfonic acid chelating agent (non-volatile content 25%)) Fly ash (fly ash cement (JIS R 5213:2019)) Retarder (citric acid-based retarder) Re-emulsified powder resin (VAEP-DA1220 (Dalian Chemical Industry Co., Ltd.)) Fiber (polyethylene fiber (fiber diameter 12 μm, length 3 mm)) Pigment (iron oxide black) Silica sand (silica sand No. 6 (average particle size (d50): approx. 0.37mm)) Crushed stone (crushed stone No. 7 (average particle size (d50): approx. 5 mm))

[0059] These were all commercially available products except for the bottom ash. The operating conditions of the biomass power plant where the bottom ash was discharged are described below.

[0060] Boiler: Direct-fired circulating fluidized bed boiler Fuel: 50% wood chips, 40% palm kernel shells, 10% coal Particulate matter: Silica sand No. 6 (average particle size (d50): approx. 0.37mm) Particle size to be removed as bottom ash 2: 0.6 mm or more

[0061] The recycled aggregate 1 and the mortar material of these test examples were subjected to the following evaluation tests.

[0062] (1) Insolubilization treatment To confirm the insolubilization treatment, elution tests were conducted on recycled aggregate 1 and mortar material for arsenic, boron, and selenium using the measurement methods in the Ministry of the Environment's Soil Environmental Standards Appendix. Leaching tests were conducted five times for each test example, and the results were evaluated as follows: ○ if the environmental conditions for arsenic, boron, and selenium were met in all five elution tests, △ if the environmental conditions for arsenic, boron, and selenium were met in three or more of the five elution tests, and × if the environmental conditions for arsenic, boron, and selenium were met in 0 to 2 of the five elution tests.

[0063] (2) Blocking resistance In the anti-blocking test, 16 kg of the mortar material was filled into powder kraft bags, and the finished mortar material was stacked vertically in five layers, and after four weeks the state of blocking (the powder solidifying into blocks) of the finished mortar material in the bottom layer was checked and judged. The evaluation was made as follows: ○: no blocking was observed; △: blocking was observed but could be easily broken down and there was no problem in use; ×: blocking was observed but could not be easily broken down and all of the mortar material in the bag could not be used.

[0064] (3) Material costs The material cost evaluation was carried out by comparing the cost per unit mass of the mortar material with our conventional product (non-shrinkage grout material). Test examples 5, 7, 9, 10, 13, 24, 26 and 28, which used ultra-rapid hardening cement, were compared with our conventional product (non-shrinkage ultra-rapid hardening grout material). Products that were cheaper than the conventional product were rated as ○, those that were the same (within ±5%) as △, and those that were more expensive as ×.

[0065] (Test Examples 1 to 14) Test Examples 1 to 14 are test examples that fall within the preferred range, with Test Example 1 being the best mode. These were evaluated as excellent in all evaluation items.

[0066] (Test Examples 15 to 21) Test Examples 15 to 21 are test examples in which the amount of water sprayed was small relative to the amount of bottom ash 2. Because the amount of water sprayed was small, the insolubilization of harmful components attached to the bottom ash 2 was poor for both the recycled aggregate 1 and the mortar material, and the results of the elution amount test sometimes did not satisfy the environmental conditions.

[0067] (Test Examples 21 to 24) Test Examples 21 to 24 are test examples in which the mortar materials have poor blocking resistance, presumably because the amount of aggregate is too large relative to the amount of cement.

[0068] (Test Examples 25 to 28) Test Examples 25 to 28 are test examples in which the material cost of the mortar material is inferior because the amount of cement is large relative to the amount of bottom ash 2. [Explanation of symbols]

[0069] 1...recycled aggregate, 2...bottom ash, 3...covering layer, 100...circulating fluidized bed boiler, 101...particulate matter, 102...biomass fuel, 103...exhaust port, 104...centrifuge, 105...high-pressure air.

Claims

1. a first step of wetting the surface of the bottom ash; a second step of mixing the moistened bottom ash with a coating material containing cement to form a mixture containing recycled aggregate composed of the bottom ash and a coating layer of the hardened coating material covering the bottom ash; a third step of mixing the mixture with a hydraulic material to form a mortar material; and The bottom ash contains harmful substances removed by the operation of a circulating fluidized bed boiler for biomass power generation, and the harmful substances are insolubilized by the coating layer formed by the hardening of the coating material, The cement of the coating material that remains unattached to the bottom ash does not undergo a hydration reaction and remains fresh; The method for producing a mortar material is characterized in that the hydraulic material has a different composition from the coating material, and a filler (aggregate) is added to the hydraulic material.

2. 2. The method for producing a mortar material according to claim 1, wherein the water content of the bottom ash after the first step is 0.2 to 10 mass %.

3. 3. The method for producing a mortar material according to claim 1, wherein the filler is silica sand and / or crushed stone.

4. 4. The method for producing a mortar material according to claim 1, wherein the hydraulic material contains a re-emulsified powdered resin as an additive.

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