Manufacturing method of γ-2CaO·SiO2-containing hydraulic clinker, cement composition, cementitious hardened body, and carbonated cementitious hardened body

Abstract

To provide a cement clinker and the like that have hydraulic hardness, low burning temperature and a high content of γ-2CaO_SiO2, and that are easily powdered and are excellent in easy pulverization properties.SOLUTION: This invention relates to a γ-2CaO_SiO2-containing hydraulic clinker and the like, which have chemical compositions of (A), (B), (C) and (D) as follows, and mineral compositions of (a), (b) and (c) as follows. [Chemical Composition] (A) a mass ratio of CaO / SiO2 is 1.9 to 2.4; (B) a total content of Al2O3 and Fe2O3 is 6 to 14 mass%; (C) a content of P2O5 is less than 0.3 mass%; and (D) a total content of Na2O and K2O is less than 1 mass%. [Mineral Composition] (a) a content of γ-2CaO_SiO2 is 20 mass% or more; (b) a content of 2CaO_Al2O3_SiO2 is 3 to 15 mass%, and / or a content of 4CaO_Al2O3_Fe2O3 is 0 to 5 mass%; and (c) a content of 12CaO_7Al2O3 is 1 to 10 mass%, and / or a content of 3CaO-Al2O3 is 0.5 to 3 mass%.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a hydraulic clinker containing γ-2CaO·SiO2 that is easily pulverized and has excellent grindability, a method for producing the same, a cement composition produced using the clinker, a cementitious hardened body such as concrete produced using the composition, and a method for producing a carbonated cementitious hardened body cured using carbon dioxide. In the present invention, the hydraulic clinker containing γ-2CaO·SiO2 refers to a hydraulic clinker having a γ-2CaO·SiO2 content of 20% by mass or more.

Background Art

[0002] For many years in the cement manufacturing field, cement has been produced using various wastes such as domestic waste and industrial waste as part of the raw materials (Patent Documents 1 to 4). Incidentally, the cement industry, which conducts activities to effectively utilize (recycle) waste and contribute to resource conservation and environmental protection, is sometimes referred to as the venous industry, likened to the veins that carry and process waste products in the body. Together with the arterial industry, it forms a recycling-based society.

[0003] However, recently, in addition to the treatment of the above-mentioned waste, suppressing and immobilizing the emission of carbon dioxide, which is the main causative substance of the increasingly serious global warming year by year, has become an urgent issue. Therefore, currently in Japan, carbon neutrality, which aims to reduce the overall emission of greenhouse gases such as carbon dioxide to zero, has been proposed, and activities for realizing a decarbonized society have become active. From such a situation, various proposals have been made regarding cement manufacturing technology.

[0004] For example, in Patent Document 5, a granulated raw material mainly composed of CaO and SiO2, with a CaO / SiO2 molar ratio of 1.8 to 2.2, a total content of Al2O3 and Fe2O3 after heating at 1000 °C of less than 5% by mass, and a particle size with a passing rate of 150 μm of 90% by mass or more is fired at a firing temperature of 1350 to 1600 °C using a rotary kiln with magnesia-spinel bricks or the like used on the inner surface of the firing zone, and a manufacturing method of γ-2CaO·SiO2 with a passing rate of 40 μm of 85% or more has been proposed. γ-2CaO·SiO2 has the property of reacting with carbon dioxide to fix carbon dioxide (Non-Patent Document 1). However, although γ-2CaO·SiO2 itself has hydraulicity under high-temperature curing such as autoclave curing, it does not have hydraulicity at normal curing temperatures. Therefore, the use of γ-2CaO·SiO2 described in Patent Document 5 is limited to admixtures for cement used by adding to hydraulic cement (paragraph 0001). Also, with the above-mentioned regulation that the total content of Al2O3 and Fe2O3 is less than 5% by mass, the use of waste containing a large amount of these compounds is restricted. For example, waste such as fly ash, construction-generated soil, and waste concrete can hardly be used, so in the manufacturing method of γ-2CaO·SiO2 described in Patent Document 5, the recycling of these wastes cannot be expected. Also, when the contents of Al2O3 and Fe2O3 are small, the melt required for firing is insufficient and it is necessary to increase the firing temperature, so the energy consumption during firing increases.

[0005] Also, in Patent Document 6, a non-hydraulic clinker material containing at least one of wollastonite and pseudowollastonite and containing particles of non-carbonated silica dispersed in a matrix containing at least one calcium silicate phase capable of carbonation has been proposed.

[0006] However, as described above, since all of the above materials do not have hydraulicity, they cannot be used in applications where hydraulicity is required such as concrete, and it is necessary to use them in combination with hydraulic materials such as cement. However, this will result in an excessive total amount of materials used, which is not preferable from the viewpoints of resource saving and energy saving.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Non-Patent Document

[0008]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] Therefore, an object of the present invention is to provide a cement clinker having hydraulicity, a low firing temperature, a high content of γ-2CaO·SiO2, which can be easily pulverized and has excellent grindability, and the like.

Means for Solving the Problems

[0010] As a result of intensive studies to solve the above problems, the present inventor has found that a cement clinker containing specific amounts of CaO, SiO2, Al2O3, Fe2O3, P2O5, Na2O, and K2O can solve the above problems, and has completed the present invention. That is, the present invention is a γ-2CaO·SiO2-containing hydraulic clinker and the like having the following configuration.

[0011] [1] A hydraulic clinker containing γ-2CaO·SiO2, having the following chemical compositions (A), (B), (C), and (D) and mineral compositions (a), (b), and (c). [Chemical composition] (A) The mass ratio of CaO / SiO2 is 1.9 - 2.4 (B) The total content of Al2O3 and Fe2O3 is 6 - 14% by mass (C) The content of P2O5 is less than 0.3% by mass (D) The total content of Na2O and K2O is less than 1% by mass [Mineral composition] (a) The content of γ-2CaO·SiO2 is 20% by mass or more (b) The content of 2CaO·Al2O3·SiO2 is 3 - 15% by mass, and and 4 The content of CaO·Al2O3·Fe2O3 is 0 - 5% by mass (c) The content of 12CaO·7Al2O3 is 1 - 10% by mass, and and 3 The content of CaO·Al2O3 is 0.5 - 3% by mass [2] The hydraulic clinker containing γ-2CaO·SiO2 according to [1] above, wherein the content of particles with a particle size of 600 μm or less is 85% by mass or more, and the content of particles with a particle size of 100 μm or less is 65% by mass or more. [3] A method for manufacturing the hydraulic clinker containing γ-2CaO·SiO2 according to [1] or [2] above, comprising at least a raw material blending step of blending one or more raw materials selected from industrial waste, general waste, contaminated soil, and construction-generated soil, and a firing and cooling step of firing and cooling the blended raw materials at 1000 - 1450 °C. [4] A cement composition containing at least the hydraulic clinker containing γ-2CaO·SiO2 according to [1] or [2] above and gypsum. [5] At least The cell according to [4] above A cementitious hardened body containing a cement composition and water. [6] At least The cell according to [4] aboveA method for producing a carbonated cementitious hardened body, which comprises contacting the mixture with carbon dioxide while kneading a ment composition, an aggregate, and water, or contacting the cementitious hardened body after the mixture has hardened with carbon dioxide to produce a carbonated cementitious hardened body.

Advantages of the Invention

[0012] The γ-2CaO·SiO2-containing hydraulic clinker of the present invention has the following effects. (1) Since the clinker of the present invention contains calcium aluminate such as 12CaO·7Al2O3 and 3CaO·Al2O3, it has hydraulicity. (2) Since the clinker of the present invention has a high content of γ-2CaO·SiO2, the amount of carbon dioxide fixed is large. (3) Since the firing temperature of the clinker of the present invention is low, the energy cost required for firing and the amount of carbon dioxide generated during firing can be reduced. (4) Since the clinker of the present invention is easily powdered, the pulverization process of the clinker can be omitted, and thus labor can be saved and production efficiency can be improved. (5) A large amount of waste can be used as a raw material. Also, regarding the effects of the invention in the method for producing the cement composition, the cementitious hardened body, and the carbonated cementitious hardened body of the present invention, similarly, the above (2) can be stated.

Modes for Carrying Out the Invention

[0013] The present invention is a γ-2CaO·SiO2-containing hydraulic clinker having the chemical compositions of (A), (B), (C) and (D) and the mineral compositions of (a), (b) and (c) above. Hereinafter, the present invention will be described in detail by dividing it into a γ-2CaO·SiO2-containing hydraulic clinker, a method for producing the same, a cement composition, a cementitious hardened body, and a method for producing a carbonated cementitious hardened body.

[0014] 1. γ-2CaO·SiO2-containing hydraulic clinker As described above, the clinker is a hydraulic clinker having the chemical compositions of (A), (B), (C) and (D) and the mineral compositions of (a), (b) and (c). Next, the compositions of (A) to (D) and (a) to (c) will be described.

[0015] (A) The mass ratio of CaO / SiO2 is 1.9 to 2.4. When the ratio is less than 1.9, α-type wollastonite or rankinite is by-produced. When the ratio exceeds 2.4, 3CaO·SiO2 or free lime (f-CaO) is by-produced. In either case, the content of γ-2CaO·SiO2 decreases. The mass ratio of CaO / SiO2 is preferably 1.95 to 2.30, more preferably 1.95 to 2.20.

[0016] (B) The total content of Al2O3 and Fe2O3 is 6 to 14% by mass. When the total content of Al2O3 and Fe2O3 is less than 6% by mass, the waste that can be used as a raw material is restricted, so there may be cases where waste cannot be used. Also, since the melt during firing decreases, the firing temperature becomes higher. On the other hand, when the content exceeds 14% by mass, the raw material melts and the fired product decreases. The total content of Al2O3 and Fe2O3 is preferably 7 to 13% by mass, more preferably 9 to 11% by mass.

[0017] (C) The P2O5 content is less than 0.3% by mass. If the P2O5 content is less than 0.3% by mass, during the cooling process of the clinker, 2CaO·SiO2 in the clinker is likely to change into pulverizable γ-2CaO·SiO2, improving the grindability of the clinker and enabling the reduction of the clinker particle size. That is, 2CaO·SiO2 changes from the γ form → β form → α form as the temperature rises, and at 1000 - 1450 °C, most of the 2CaO·SiO2 becomes the α form or β form. Although these 2CaO·SiO2 have the property of returning from the α form → β form → γ form during the cooling process, if P2O5, Na2O, or K2O is present, they cannot fully return to the γ form. In the present invention, by utilizing the above property of 2CaO·SiO2 and specifying the P2O5 content that can fully return to the γ form to be less than 0.3% by mass, if this content is satisfied, simply through the simple process of cooling, a clinker with good grindability can be produced, which is a technical feature unique to the present invention. Incidentally, the P2O5 content is preferably less than 0.25% by mass.

[0018] (D) The total content of Na2O and K2O is less than 1% by mass. If the total content of Na2O and K2O is less than 1% by mass, similar to the above P2O5, during the cooling process of the clinker, 2CaO·SiO2 in the clinker is likely to change into pulverizable γ-2CaO·SiO2, improving the grindability of the clinker and enabling the reduction of the clinker particle size. In the present invention, in addition to the above P2O5, by specifying the total content of Na2O and K2O to be less than 1% by mass, simply through the simple process of cooling, the point that a clinker with good grindability can be produced is also a technical feature unique to the present invention. Incidentally, the total content of Na2O and K2O is preferably less than 0.90% by mass, more preferably less than 0.80% by mass. Here, as a method for reducing Na2O and K2O (alkali components) in clinker, a method of adding a chlorine source to the raw materials and firing them (chlorine bypass method or chlorination volatilization method) can be used by taking advantage of the property that alkali and chlorine turn into chlorides of alkali metals and volatilize and concentrate in a high-temperature firing furnace. Specifically, this method is a method of extracting a part of the combustion gas containing the alkali volatilized in the raw materials from the exhaust gas flow path of the firing furnace, cooling it, and separating and removing the dust in which the chloride of the generated alkali metal is concentrated.

[0019] (a) The content of γ-2CaO·SiO2 is 20% by mass or more. If the content of γ-2CaO·SiO2 is 20% by mass or more, the clinker after being cooled in the cooler is pulverized, and there is no need to separately provide a pulverization process. The content of γ-2CaO·SiO2 is preferably 25% by mass or more, more preferably 30% by mass or more.

[0020] (b) The content of 2CaO·Al2O3·SiO2 is 3 to 15% by mass, and / or the content of 4CaO·Al2O3·Fe2O3 is 0 to 5% by mass. If the content of 2CaO·Al2O3·SiO2 and / or 4CaO·Al2O3·Fe2O3 is within the above range, the carbon dioxide absorption capacity of the clinker becomes higher. The content of 2CaO·Al2O3·SiO2 and 4CaO·Al2O3·Fe2O3 is preferably 8 to 20% by mass.

[0021] (c) The content of 12CaO·7Al2O3 is 1 to 10% by mass, and / or the content of 3CaO·Al2O3 is 0.5 to 3% by mass. If the content of 12CaO·7Al2O3 and / or 3CaO·Al2O3 is within the above range, the initial hydration activity of the clinker is high without a decrease in fluidity. The content of 12CaO·7Al2O3 and 3CaO·Al2O3 is preferably 1.5 to 13% by mass.

[0022] In addition to the γ-2CaO·SiO2, 2CaO·Al2O3·SiO2, 4CaO·Al2O3·Fe2O3, 12CaO·7Al2O3, and 3CaO·Al2O3 of the present invention, as shown in Table 3 below, the clinker also contains minerals such as β-2CaO·SiO2, α-2CaO·SiO2, and f-CaO (free lime). The content of the free lime (f-CaO), which is a trace component in the clinker, is preferably 2.0% by mass or less. When the content of free lime exceeds 2.0% by mass, the cementitious hardened body may be destroyed due to the expansion caused by the hydration of free lime, and the fluidity of the cement composition may decrease, resulting in the inability to ensure the working time for operations such as placing concrete. The content of free lime in the clinker is more preferably 1.5% by mass or less, and even more preferably 1.0% by mass or less. The minerals can be quantified by Rietveld analysis by fitting the theoretical profiles of the respective minerals to the powder X-ray diffraction chart (measured profile) of the clinker of the present invention, and commercially available analysis software can be used for this quantification.

[0023] As described above, the γ-2CaO·SiO2-containing hydraulic clinker of the present invention is easily pulverized during cooling, and this pulverized clinker can basically be used as the clinker component of the cement composition without being pulverized. For direct use, the clinker of the present invention preferably has a content of particles with a particle size of 600 μm or less of 85% by mass or more, and a content of particles with a particle size of 100 μm or less of 65% by mass or more. Here, the content of particles with a particle size of 600 μm or less being 85% by mass or more means that the proportion of particles passing through a sieve with a nominal aperture of 600 μm is 85% by mass or more, and the content of particles with a particle size of 100 μm or less being 65% by mass or more means that the proportion of particles passing through a sieve with a nominal aperture of 106 μm is 85% by mass or more. The clinker of the present invention is more preferably such that the content of particles with a particle size of 600 μm or less is 90% by mass or more, and the content of particles with a particle size of 100 μm or less is 70% by mass or more. In addition, if the particle size of the clinker of the present invention is defined by the Blaine specific surface area, it is preferably 2000 - 6000 cm2 / g, more preferably 2500 to 5000 cm 2 / g, even more preferably 2500 to 4000 cm 2 / g.

[0024] 2. Method for producing hydraulic clinker containing γ-2CaO·SiO2 The production method includes, as essential steps, (1) a raw material blending step and (2) a firing and cooling step, and also includes, as an optional step, (3) a grinding step. (1) Raw material blending step In this step, as raw materials, one or more kinds of waste materials selected from industrial waste, general waste, construction-generated soil, etc. are used, and they are blended so as to fall within the range of the mineral composition of the clinker. The industrial waste includes fly ash, fresh concrete sludge, concrete waste, purified water sludge, construction sludge, steelmaking sludge, construction waste, foundry sand, rock wool, waste glass, blast furnace secondary ash, and boring waste soil, etc. The general waste includes sewage sludge dry powder, municipal waste incineration ash, sewage sludge dry powder, shells, and sewage sludge incineration ash, etc. Further, the construction-generated soil includes soil generated from construction sites or work sites, surplus soil, and waste soil, etc.

[0025] Also, when it is difficult to blend only the waste materials so that the mineral composition of the clinker falls within the above range, it may be supplemented with natural raw materials such as calcium raw materials, silicon raw materials, aluminum raw materials, and iron raw materials. Here, calcium raw materials include limestone, quicklime, slaked lime, and steelmaking slag, etc.; silicon raw materials include silica and clay, etc.; aluminum raw materials include clay, etc.; and iron raw materials include iron slag and iron cake, etc.

[0026] Also, when it is necessary to adjust the particle size of the raw materials, it may be adjusted by grinding with a grinder such as a ball mill until it reaches a predetermined particle size. Also, the raw materials may be granulated to facilitate firing. Examples of this granulation method include a rolling granulation method, an extrusion granulation method, and a compression granulation method, etc.

[0027] (2) Firing and cooling step After firing the blending raw materials in a firing furnace such as a rotary kiln, the easily pulverizable clinker of the present invention can be obtained by cooling with a cooler. Here, the firing temperature of the clinker of the present invention is preferably 1000 to 1450 °C. If the firing temperature is less than 1000 °C, it is difficult to reduce the free lime in the clinker, and if it exceeds 1450 °C, the raw materials may melt and the fired product (clinker) may decrease. The firing temperature is more preferably 1100 to 1400 °C, and even more preferably 1150 to 1350 °C. Also, the firing time is preferably 30 to 150 minutes. If the time is less than 30 minutes, the firing is not sufficient, and if it exceeds 150 minutes, the productivity decreases. The firing time is more preferably 40 to 120 minutes. In addition, since the cooler promotes the pulverization of the clinker by rolling, it is preferably a rotary cooler.

[0028] (3) Grinding process In the present invention, since the clinker is pulverized in the cooler during cooling, the grinding process is basically unnecessary. However, for example, in order to make the content of particles having a particle size of 600 μm or less 90% by mass or more, which is in a more preferable range, of 85% by mass or more in the above preferable range, it may be pulverized using a grinder such as a ball mill or a rod mill. Further, when the clinker contains particles having a particle size of 1 mm or more, since these particles hardly contribute to the development of strength, the clinker may be sieved to remove these particles. In addition, in order to improve the efficiency of the grinding, it is preferable to add a grinding aid and grind. Examples of the grinding aid include diethylene glycol, triethanolamine, and triisopropanolamine. The addition ratio of these grinding aids is preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the clinker.

[0029] 3. Cement composition and cementitious hardened body The cement composition of the present invention is a composition containing at least the γ-2CaO·SiO2-containing hydraulic clinker and gypsum. The gypsum includes one or more selected from anhydrous gypsum, dihydrate gypsum, and hemihydrate gypsum. Further, considering the balance between ensuring the workable time and the strength development property, the content of gypsum in the composition is preferably 0.1 to 5.0% by mass, more preferably 0.5 to 4.0% by mass, and still more preferably 1.0 to 3.0% by mass in terms of SO3 conversion.

[0030] In addition, the cement composition of the present invention can be produced by the following method. (1) It is produced by mixing the clinker and gypsum having a predetermined particle size using a mixer such as a blending tank. (2) After mixing the clinker and gypsum, the mixed raw material is pulverized using a pulverizer such as a ball mill or a rod mill and adjusted to a predetermined particle size for production.

[0031] And from the viewpoints of strength development property, workability, cost, etc., the Blaine specific surface area of the composition is preferably 2000 to 6000 cm 2 / g, more preferably 3000 to 5000 cm 2 / g, and still more preferably 3000 to 4000 cm 2 / g.

[0032] In addition, in the pulverization of the mixed raw material, the mixed raw material as it is may be pulverized, but preferably, a pulverization aid is added for pulverization in order to improve the pulverization efficiency. Examples of the pulverization aid include diethylene glycol, triethanolamine, and triisopropanolamine. Among these, triisopropanolamine is more preferable because the strength development property of the cement composition is improved. The addition ratio of these pulverization aids is preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the clinker. Note that the cement composition of the present invention may further contain Portland cement clinker powder, blast furnace slag powder, fly ash, limestone powder, coal ash, silica powder, silica fume, etc. according to the required strength development property, durability, workability, etc.

[0033] The cementitious hardened body of the present invention is a hardened body containing at least the cement composition and water, and can react with carbon dioxide to fix carbon dioxide. The hardened body includes concrete, mortar, and cement paste hardened bodies. And the forms of the hardened body include concrete structures, concrete products, concrete pavements, and powdery and granular materials of concrete, etc.

[0034] 5. Method for producing a carbonated cementitious hardened body. The production method is a method for producing a carbonated cementitious hardened body by contacting the kneaded material with carbon dioxide while kneading at least the cement composition, aggregate, and water, or by contacting the cementitious hardened body after the kneaded material has hardened with carbon dioxide. Here, the "contacting with carbon dioxide" includes (i) blowing carbon dioxide into the kneaded material while kneading, and (ii) exposing the cementitious hardened body to carbon dioxide. In the mode of (i), since carbonation proceeds mainly by the solid-liquid reaction between γ-2CaO·SiO2 and carbon dioxide dissolved in the liquid phase in the kneaded material, the immobilization of carbon dioxide is relatively fast. In the mode of (ii), the cementitious hardened bodies to be carbonated include concrete products, concrete structures, concrete pavements, etc., as well as their wastes (such as crushed materials and dismantled materials), and cover a wide range. In addition, in the carbonation of the cementitious hardened body, γ-2CaO·SiO2 in the hardened body reacts with carbon dioxide and expands, so that the pores on the surface and inside of the hardened body are filled and the structure becomes denser, improving the durability of the hardened body.

[0035] The concentration of carbon dioxide used for the carbonation is preferably 1% by volume or more. If the concentration is 1% by volume or more, the carbonation is fast enough. The concentration is more preferably 10% by volume or more, still more preferably 50% by volume or more, and particularly preferably 60% by volume or more.

[0036] The temperature of the carbonation is preferably 5 to 100 °C. If the temperature is 5 °C or higher, the carbonation proceeds rapidly, improving the productivity of the carbonated cementitious hardened body and increasing the strength of the carbonated cementitious hardened body. If it exceeds 100 °C, the production cost becomes excessive. The temperature of the carbonation is more preferably 10 to 70 °C, still more preferably 15 to 50 °C, and particularly preferably 20 to 35 °C. In addition, for the purpose of suppressing the production cost, the carbon dioxide may be factory exhaust gas, for example, carbon dioxide-containing gas discharged from a cement factory. Also, the carbon dioxide in the factory exhaust gas may be separated and recovered using an amine and regenerated into a high-concentration carbon dioxide gas, or a gas with an increased carbon dioxide concentration obtained using a mixed gas of oxygen or a mixture of oxygen and carbon dioxide instead of air as the firing gas.

[0037] The relative humidity of the carbonation is preferably 20 to 90%. When the relative humidity is 20% or more, the carbonation proceeds rapidly, improving the productivity of the carbonated cementitious hardened body and increasing the strength of the hardened body. On the other hand, it is difficult for the relative humidity to exceed 90%, and the cost for equipment and the like becomes excessive. The relative humidity is more preferably 30 to 80%, and still more preferably 40 to 70%.

Examples

[0038] Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to these examples. 1. Production of hydraulic clinker containing γ-2CaO·SiO2 A prepared raw material prepared by mixing lime powder, clay powder, iron oxide powder, soda ash, calcium chloride, and tricalcium phosphate so as to have the chemical composition shown in Table 1 was fired under the firing conditions shown in Table 1 using a pilot kiln and a rotary cooler to produce clinker. Heavy oil was used as the fuel, and the flow rate of the heavy oil and the rotation speed of the kiln were adjusted so as to satisfy the firing conditions shown in Table 1.

[0039]

Table 1

[0040] Also, the chemical composition, etc. of the manufactured clinker are shown in Table 2, and the mineral composition, particle size distribution, and Blaine specific surface area of the clinker are shown in Table 3. The particle size distribution of the clinker was measured by the laser diffraction / scattering method using a particle size distribution measuring device (product name: Microtrac HRA model 9320-X100, manufactured by Nikkiso Co., Ltd.). This measurement was performed by adding 0.06 g of clinker to 30 cm 3 of ethanol, which is a dispersion medium, and ultrasonically dispersing it with an ultrasonic dispersing device (product name: US300, manufactured by Nihon Seiki Seisakusho Co., Ltd.) for 90 seconds.

[0041]

Table 2

[0042]

Table 3

[0043] As shown in Table 2 and Table 3, the lower the contents of Na2O, K2O, and P2O5 in the clinker, the more the clinker becomes powdered and the finer the particles become.

Claims

Claim 1 A γ-2CaO·SiO containing hydraulic clinker having the following chemical compositions (A), (B), (C) and (D) and the following mineral compositions (a), (b) and (c). ２ ​ Chemical composition (A) The mass ratio of CaO / SiO ２ is 1.9 to 2.4 (B) Al ２ O ３ and Fe ２ O ３ The total content of which is 6 to 14% by mass (C) P ２ O ５ with a content of less than 0.3% by mass (D) Na ２ O and K ２ The total content rate of O is less than 1% by mass Mineral composition (a) γ-2CaO·SiO ２ with a content of 20% by mass or more (b) 2CaO·Al ２ O ３ ·SiO ２ content is 3 to 15% by mass, and 4CaO·Al ２ O ３ ·Fe ２ O ３ content is 0 to 5% by mass (c) 12CaO·7Al ２ O ３ content is 1 to 10% by mass, and 3CaO·Al ２ O ３ content is 0.5 to 3% by mass Claim 2 The γ-2CaO·SiO according to claim 1, having a content of particles with a particle size of 600 μm or less of 85% by mass or more, and a content of particles with a particle size of 100 μm or less of 65% by mass or more ２ Hydraulic clinker containing Claim 3 A raw material blending step of blending one or more raw materials selected from industrial waste, general waste, contaminated soil, and construction-generated soil, and a firing / cooling step of firing and cooling the blended raw materials at 1000 to 1450°C, at least including the method for producing a γ-2CaO·SiO ２ Containing hydraulic clinker. Claim 4 The cement composition according to claim 1 or 2, comprising a γ-2CaO·SiO ２ hydraulic clinker containing at least gypsum. Claim 5 A cementitious hardened body comprising at least the cement composition according to claim 4 and water. Claim 6 A method for producing a carbonated cementitious hardened body, wherein at least the cement composition according to claim 4, aggregates, and water are kneaded, and the kneaded material is brought into contact with carbon dioxide, or the cementitious hardened body after the kneaded material has hardened is brought into contact with carbon dioxide to produce a carbonated cementitious hardened body.

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