Calcium-based carbonate compound and inorganic molded body

Abstract

To provide a calcium-based carbonate compound which enables the fluidity of a mixture thereof to be maintained during the production process, while improving the strength of the molded body; and also to provide an inorganic molded body.SOLUTION: Provided is a cubic calcium-based carbonate compound that has a phosphorus atom content of at most 1,000 ppm and a sulfur atom content of at least 100 ppm. The average particle diameter of the calcium-based carbonate compound is preferably 2 μm to 25 μm inclusive as measured by a laser diffraction method. The BET specific surface area of the calcium-based carbonate compound is preferably 0.3 m2 / g to 3 m2 / g inclusive.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to calcium-based carbonate compounds and inorganic molded bodies.

Background Art

[0002] An inorganic molded body is a molded body mainly composed of inorganic substances such as hydraulic materials and siliceous materials, and has characteristics such as fire resistance, light weight, high strength, and workability. Therefore, it is widely used for exterior wall materials, roof base materials, eaves and ceiling materials of houses, etc. It is also widely used for the foundation parts, walls, columns, floors, etc. of buildings where strength and fire resistance are required.

[0003] As a technique for increasing the strength, which is one of the important performances required for inorganic molded bodies, a technique of blending acicular calcium carbonate has been proposed (Japanese Patent No. 6898926).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the strength of the inorganic molded body obtained by the above technique may decrease, and the fluidity of the raw material mixture in the manufacturing process may decrease, and as a result, the work efficiency in the entire manufacturing process may decrease.

[0006] An object of the present invention is to provide a calcium-based carbonate compound and an inorganic molded body capable of improving the strength of the molded body while maintaining the fluidity of the mixture in the manufacturing process.

Means for Solving the Problems

[0007] As a result of intensive studies, the inventors of the present invention have found that the following configuration can solve the above problems, and have completed the present invention.

[0008] In one embodiment, the present invention has a phosphorus atom content of 1000 ppm or less, and a sulfur atom content of 100 ppm or more relates to a cubic calcium-based carbonate compound.

[0009] As a result of the studies by the inventors of the present invention, as a factor for acicularization or rod-like formation (hereinafter also collectively referred to as "acicularization, etc.") that results in a high aspect ratio during the crystal growth of the calcium-based carbonate compound, the phosphorus atom acts as a factor that promotes acicularization, etc., and the sulfur atom acts as a factor that inhibits acicularization, etc. Since the calcium-based carbonate compound has a phosphorus atom and a sulfur atom content within a specific range, the shape can be efficiently controlled to a cubic shape.

[0010] On the other hand, in the field of inorganic molded articles, it is widely known to increase the strength of inorganic molded articles by using acicular or fibrous reinforcing materials such as acicular calcium carbonate. However, if the blending amount of the acicular reinforcing material is increased for further strength improvement, the fluidity of the mixture will decrease as described above. Therefore, improving the strength and maintaining the fluidity are in a so-called trade-off relationship. As a result of repeated studies by the inventors of the present invention, surprisingly, it has been found that a cubic calcium-based carbonate compound can improve the strength of the obtained inorganic molded article while maintaining the fluidity of the mixture during the production process.

[0011] The present invention has been completed by developing these new findings.

[0012] Although the reason why the calcium carbonate compound can achieve both fluidity and strength is not clear, it is presumed as follows. Since the calcium carbonate compound is cubic, the shear stress in the mixture decreases, and the viscosity increasing effect becomes smaller than that of the needle-shaped material. As a result, the fluidity of the mixture can be maintained. In addition, the strength of the inorganic molded body can be improved by the improvement of the strength and density of the calcium carbonate compound itself due to its cubic shape and the homogeneous dispersion or homogeneous filling due to the isotropy (non-orientation) in the mixture. Furthermore, the viscosity of the mixture containing the needle-shaped material is high, and the bubbles in the mixture are difficult to escape. If the final product is obtained with the bubbles remaining, the strength of the final product may decrease. It is presumed that in the case of the cubic calcium carbonate compound, the bubbles in the mixture are likely to escape due to the fluidity and isotropy as described above, and thus it is also possible to prevent or improve the decrease in strength in this respect.

[0013] In this specification, "cubic" does not refer to a regular cubic shape, but refers to a shape that can be regarded as approximately cubic. For example, even if one or more of the vertices of the cube are rounded or chipped, if the cube can be restored by complementing that part, it is cubic. Also, if the length of one side of the target shape is within the range of 50% or more and 150% or less of the length of the other side, the target shape is cubic. Furthermore, the shape of one surface of the target shape is not limited to a square, and as long as the ratio of the lengths of the two sides is satisfied, it may be any shape such as a trapezoid, a rhombus, or a quadrilateral with different lengths of the four sides. In addition, it is not necessary for all the particles constituting the calcium carbonate compound to be cubic. When the ratio of the cubic particles among all the particles is the largest, the calcium carbonate compound is cubic.

[0014] In this specification, the "calcium-based carbonate compound" is a compound mainly composed of calcium carbonate, and is a concept that allows the inclusion or coexistence of other minor components that can be incorporated in the manufacturing process or the like. The calcium carbonate content in the calcium-based carbonate compound is preferably 90% by mass or more. As a method for measuring the content ratio of calcium carbonate in the calcium-based carbonate compound, the disodium ethylenediaminetetraacetate titration method can be preferably adopted.

[0015] <Disodium ethylenediaminetetraacetate titration method> Weigh 1 g of the calcium-based carbonate compound (dried at 105°C for 2 hours) as a sample, suspend it in 50 mL of water, add 10 mL of hydrochloric acid (a solution prepared by mixing concentrated hydrochloric acid and water in a volume ratio of 1:1), and heat and dissolve it. After cooling, transfer it to a 250 mL volumetric flask, add water to make up to the same volume. Take 5.00 mL from this, and add water so that the total volume of the solution is about 50 mL. Add 5 mL of buffer solution (a solution prepared by dissolving 500 g of potassium hydroxide in water to make 1,000 mL), and further add a commercially available dithizone NN dilution powder, and titrate with a titrant (a solution prepared by dissolving about 3.8 g of disodium ethylenediaminetetraacetate in water to make 1,000 mL). End the titration when the color of the solution changes from red to blue. Calculate the calcium carbonate content (%) according to the following formula.

[0016]

Number

[0017] In one embodiment, the average particle size of the calcium-based carbonate compound by the laser diffraction method is preferably 2 μm or more and 25 μm or less. In one embodiment, the BET specific surface area of the calcium-based carbonate compound is 0.3 m 2 / g or more and 3 m 2It is preferably below / g. Further, in one embodiment, the apparent specific gravity of the calcium carbonate compound is preferably 1 g / mL or more and 2 g / mL or less. By satisfying these characteristics alone or in combination, it is possible to achieve a higher level of compatibility between fluidity and strength.

[0018] In one embodiment, according to the calcium carbonate compound, the P-funnel flow-down time can be 7 seconds or more and 10 seconds or less. Thereby, the calcium carbonate compound can exhibit good fluidity.

[0019] In one embodiment, the magnesium content in the calcium carbonate compound may be 1000 ppm or more. The magnesium content in the calcium carbonate compound varies depending on raw materials, production methods, etc. For example, when using raw materials relatively rich in magnesium (such as seawater), the magnesium content in the calcium carbonate compound will be 1000 ppm or more. When using raw materials relatively low in magnesium (such as the supernatant of concrete sludge), the magnesium content in the calcium carbonate compound will be less than 1000 ppm.

[0020] In one embodiment, the calcium carbonate compound is preferably a synthetic calcium carbonate compound in terms of production efficiency and shape controllability.

[0021] In other embodiments of the present invention, The present invention relates to an inorganic molded body containing the calcium carbonate compound.

[0022] By applying a cubic calcium carbonate compound to an inorganic molded body, it is possible to efficiently obtain an inorganic molded body with high strength while maintaining fluidity during the manufacturing process and ensuring good workability.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

BEST MODE FOR CARRYING OUT THE INVENTION

[0024] The calcium-based carbonate compound and the inorganic molded body according to an embodiment of the present invention will be described below. The present invention is not limited to these embodiments.

[0025] <Calcium-based carbonate compound> The calcium-based carbonate compound according to the present embodiment is cubic. In the calcium-based carbonate compound, the content of phosphorus atoms is 1000 ppm or less, and the content of sulfur atoms is 100 ppm or more.

[0026] In the calcium-based carbonate compound, as long as the content of phosphorus atoms is 1000 ppm or less, it is not particularly limited. The content of phosphorus atoms is preferably 500 ppm or less, more preferably 100 ppm or less. On the other hand, although the content of phosphorus atoms is preferably as small as possible, it may be contained in an amount of about 1 ppm. By setting the content of phosphorus atoms, which is one factor for the acicularization of the calcium-based carbonate compound, to the predetermined amount, a cubic calcium-based carbonate compound can be efficiently formed.

[0027] In the calcium-based carbonate compound, as long as the content of sulfur atoms is 100 ppm or more, it is not particularly limited. It is preferably 500 ppm or more, more preferably 1000 ppm or more. The content of sulfur atoms is preferably 10000 ppm or less, more preferably 5000 ppm or less. By setting the content of sulfur atoms to the predetermined amount, an inhibitory action such as acicularization can be achieved, and a cubic calcium-based carbonate compound can be efficiently obtained.

[0028] The average particle size of the calcium carbonate compound by the laser diffraction method is preferably 2 μm or more and 25 μm or less, more preferably 4 μm or more and 22 μm or less, and even more preferably 6 μm or more and 18 μm or less. Thereby, the fluidity of the mixture containing the calcium carbonate compound can be suitably maintained. In addition, the strength of the obtained inorganic molded body can be further improved.

[0029] The BET specific surface area of the calcium carbonate compound is preferably 0.3 m 2 / g or more and 3 m 2 / g or less, more preferably 0.4 m 2 / g or more and 2.6 m 2 / g or less, and even more preferably 0.5 m 2 / g or more and 2.4 m 2 / g or less. Thereby, the fluidity of the mixture containing the calcium carbonate compound can be suitably maintained, and the dispersibility of the calcium carbonate compound can also be improved. In addition, the strength of the obtained inorganic molded body can be further improved.

[0030] The apparent specific gravity of the calcium carbonate compound is preferably 1.00 g / mL or more and 2.00 g / mL or less, more preferably 1.05 g / mL or more and 1.80 g / mL or less, and even more preferably 1.10 g / mL or more and 1.60 g / mL or less. Thereby, the fluidity of the mixture containing the calcium carbonate compound can be suitably maintained. In addition, the density and strength of the calcium carbonate compound are increased, and the strength of the obtained inorganic molded body can be further improved.

[0031] The P funnel flow-down time of the calcium carbonate compound is preferably 7 seconds or more and 10 seconds or less, more preferably 7.5 seconds or more and 9.8 seconds or less, and even more preferably 8 seconds or more and 9.5 seconds or less. Since the calcium carbonate compound is cubic, excellent fluidity can be exhibited.

[0032] The magnesium content in the calcium-based carbonate compound may be 1000 ppm or more, may be 5000 ppm or more, or may be 10000 ppm or more. The upper limit of the magnesium content is about 50000 ppm depending on raw materials, manufacturing methods, etc.

[0033] As the crystal structure of the calcium-based carbonate compound, a calcite type, an aragonite type, or a combination thereof can be preferably adopted. From the viewpoint of obtaining a cubic calcium-based carbonate compound, it is preferable that the calcite type crystal structure is relatively more and the aragonite type crystal structure is relatively less.

[0034] In the X-ray diffraction measurement of the calcium-based carbonate compound, the peak intensity I a of calcite and the peak intensity I c of aragonite, the ratio I a / I c is preferably 0.1 or less, more preferably 0.08 or less, and even more preferably 0.06 or less. Thereby, a cubic calcium-based carbonate compound can be efficiently obtained.

[0035] The calcium-based carbonate compound is preferably a synthetic calcium-based carbonate compound in terms of production efficiency and shape controllability.

[0036] (Method for producing calcium-based carbonate compound) The method for producing the calcium-based carbonate compound is not particularly limited, and a known production method can be adopted. Typically, a solution method for producing a calcium-based carbonate compound by contacting a carbonate (carbonate ion) with calcium (calcium ion) such as seawater to perform salt exchange can be preferably adopted. Ca 2+ +CO3 2- →CaCO3(A)

[0037] As the salt of carbonate ion used in the reaction formula (A), alkali metal salts (Li, Na, K) and alkaline earth metal salts (Mg, Sr, excluding Ca) are used, and among them, alkali metal salts are preferably used. Among them, the Na salt (sodium carbonate) is preferable in terms of versatility and cost.

[0038] The contact between the carbonate and seawater or the like may be carried out by introducing an aqueous solution or slurry of the carbonate into the seawater or the like, or by introducing the seawater or the like into the aqueous solution or slurry. From the viewpoint of efficiently obtaining the target cubic calcium-based carbonate compound, it is preferable to introduce it all at once.

[0039] Seawater may be used as it is pumped directly from the nearby sea, or may be used after treatment such as filtration. The pumping is not limited to the offshore area, and can be carried out at any place as long as seawater can be obtained. Calcium-rich seawater generated when removing magnesium hydroxide from seawater may also be used.

[0040] The input amount of the carbonate is not particularly limited as long as it is set so as to obtain the amount of carbonate ion necessary for the reaction with the amount of calcium ion in seawater or the like according to the above reaction formula (A). Although an equimolar amount of the calcium ion amount and the carbonate ion amount is preferable, the carbonate ion amount may be in the range of 50 to 200% in terms of molar ratio with respect to the calcium ion amount.

[0041] The salt exchange reaction by the contact between the carbonate and seawater or the like proceeds relatively rapidly. The reaction time may be set to such an extent that the salt exchange reaction proceeds sufficiently, and can be set to 1 second or more, preferably 1 minute or more and 60 minutes or less, and more preferably 5 minutes or more and 50 minutes or less.

[0042] The generated calcium-based carbonate compound may be filtered and dried to form a powder, or may be used as a calcium-based carbonate compound source in the form of a slurry or a cake without going through filtration and drying.

[0043] <Uses of Calcium-based Carbonate Compounds> The use of the calcium-based carbonate compound is not particularly limited. As uses, for example, it is suitable as a high-functional material for inorganic molded bodies typified by building materials and buildings, a filler for resins, and the like. Hereinafter, embodiments of using the calcium-based carbonate compound in an inorganic molded body will be described.

[0044] <Inorganic molded body> The inorganic molded body is not particularly limited, and typically includes a molded plate for building materials, a concrete building (concrete molded body), and the like. Hereinafter, applicable compositions and the like will be described in detail according to the use.

[0045] (Molded plate for building materials) The molded plate preferably contains a hydraulic material, a siliceous material, a reinforcing fiber material, and a calcium-based carbonate compound.

[0046] (Hydraulic material) Examples of the hydraulic material include cementitious materials, gypsum, lime, slag, and the like. Examples of the cementitious materials include commonly used cements such as ordinary Portland cement, early-strength cement, medium-heat cement, fly ash cement, blast furnace slag cement, and alumina cement. Examples of the gypsum include anhydrous gypsum, hemihydrate gypsum, dihydrate gypsum, and the like. Examples of the slag include blast furnace slag, converter slag, and the like. These hydraulic materials can be used alone or in combination of two or more.

[0047] The content of the hydraulic material is preferably 5% by mass or more and 45% by mass or less, more preferably 8% by mass or more and 42% by mass or less, and even more preferably 10% by mass or more and 40% by mass or less based on the total amount of the materials constituting the molded plate. By setting the content of the hydraulic material within the above range, physical properties such as the flexural strength and peel strength of the molded plate can be improved, and the high-bulk specific gravity of the molded plate can be suppressed to enhance the workability during construction and the like.

[0048] (Siliceous material) Examples of siliceous materials include materials rich in SiO2 such as silica sand, silica powder, silica fume, fly ash, diatomaceous earth, layered silicates (e.g., mica, talc, kaolin, bentonite), wollastonite, lightweight aggregates (e.g., fly ash balloons, perlite, shirasu balloons, glass foams, etc.). These siliceous materials can be used alone or in combination of two or more. Talc, mica, and wollastonite can also be used as the reinforcing fiber materials described later.

[0049] The content of the siliceous material is preferably 10% by mass or more and 55% by mass or less, more preferably 12% by mass or more and 50% by mass or less, and even more preferably 15% by mass or more and 45% by mass or less, based on the total amount of the materials constituting the molded plate. If the content of the siliceous material is within the above range, it becomes possible to set the flexural strength, bulk specific gravity, water absorption rate, dimensional stability, etc. of the molded plate within the desired range. Note that as the siliceous material, perlite, fly ash balloons, shirasu balloons, etc. with a unit volume mass of 0.5 g / cm 3 When blending the following lightweight aggregates, in order to prevent the bulk specific gravity from becoming too light and the strength such as flexural strength and peel strength from becoming weak, it is preferable to use other siliceous materials in combination so that the content of the lightweight aggregate is 20% by mass or less based on the total amount of the materials constituting the molded plate.

[0050] (Reinforcing fiber material) Examples of the reinforcing fiber material include pulp such as softwood pulp, hardwood pulp, fibrillated pulp of these, and pulp obtained by defibrating waste paper, organic reinforcing fiber materials such as vinylon fiber, acrylonitrile fiber, and polypropylene fiber, and inorganic reinforcing fiber materials such as rock wool and glass fiber. These reinforcing fiber materials can be used alone or in combination of two or more.

[0051] In order to improve the strength of the formed plate and impart toughness, the content of the reinforcing fiber material is preferably 2% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 26% by mass or less, and even more preferably 4% by mass or more and 22% by mass or less, based on the total amount of the materials constituting the formed plate. By setting the content of the reinforcing fiber material within the above range, while exerting a sufficient reinforcing effect, it is possible to suppress the fibers from protruding on the surface of the formed plate and improve the smoothness. When an inorganic reinforcing fiber material with an average length of 1 mm to 50 mm is blended as the reinforcing fiber material, in order to improve the smoothness of the formed plate, it is preferable to use other reinforcing fiber materials in combination so that the content is 10% by mass or less based on the total amount of the materials constituting the formed plate.

[0052] (Calcium-based carbonate compound) As the calcium-based carbonate compound, the above-mentioned calcium-based carbonate compound can be preferably adopted.

[0053] The content of the calcium-based carbonate compound is preferably 5% by mass or more and 60% by mass or less, more preferably 8% by mass or more and 55% by mass or less, and even more preferably 12% by mass or more and 50% by mass or less, based on the total amount of the materials constituting the formed plate. By blending a calcium-based carbonate compound with low thermal conductivity in the content within the above range, the strength and fire resistance of the formed plate can be improved.

[0054] (Optional component) In addition to the above materials, in order to impart various functions to the formed plate, materials such as resin hollow bodies, wood chips, wood powder, resin powder, defoamers, flocculants, water repellents, thickeners (such as methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, etc.), and dispersants can be variously blended according to the purpose. It is also possible to appropriately add and use recycled materials obtained by pulverizing end materials generated during the processing of the formed plate.

[0055] The bulk density of the formed plate is preferably 0.7 g / cm 3 or more and 2.0 g / cm 3 or less, more preferably 0.8 g / cm 3 or more and 1.8 g / cm3 More preferably, it is as follows, 0.9 g / cm 3 or more and 1.6 g / cm 3 or less is even more preferable.

[0056] (Manufacturing method of the formed plate) The manufacturing method of the formed plate according to this embodiment is not particularly limited, and generally used papermaking methods, extrusion molding methods, flow-on molding methods, pouring molding methods, press (compression) molding, etc. can be used. The formed plate can be obtained by subjecting the green sheet formed by these methods to press dehydration or pattern processing such as embossing, and then curing by room temperature curing, steam curing, autoclave curing, etc. Furthermore, drying may be performed, and shape processing or painting may be performed as necessary.

[0057] (Uses of the formed plate) The uses of the formed plate are not particularly limited, and it can be suitably used as interior and exterior finishing materials such as building wall materials, floor materials, roof materials, various boards, exterior decoration members, furniture, etc., and performance maintenance materials such as sealing materials, heat insulation materials, sound absorption materials, waterproof materials, etc. The formed plate is preferably a cement-based formed plate containing a cementitious material, and more preferably a calcium silicate formed body.

[0058] (Concrete building) The concrete building is composed of a hardened body of a hydraulic composition. The hydraulic composition is composed of a powder containing at least one of blast furnace slag, an expansive material, slaked lime, quicklime, fly ash, and Portland cement in addition to a calcium-based carbonate compound. As the calcium-based carbonate compound, the above-mentioned calcium-based carbonate compound can be preferably adopted.

[0059] In addition to the above-mentioned hydraulic composition, aggregates such as sand and gravel, chemicals such as chemical admixtures for concrete, and fiber materials made of metals or polymer materials may be blended to form a hydraulic composition mixture material.

[0060] The hardened body of the hydraulic composition is obtained by hardening the paste obtained by kneading water into the above-mentioned hydraulic composition. Further, the hardened body of the hydraulic composition mixture material is obtained by hardening the kneaded material (corresponding to fresh mortar or fresh concrete) obtained by kneading water into the above-mentioned hydraulic composition mixture material, and corresponds to mortar or concrete.

[0061] The proportion of the calcium-based carbonate compound in the powder (the proportion of the calcium-based carbonate compound to cement) is in the range of 1% to 60% by mass, preferably 3% to 50% by mass, and more preferably 5% to 40% by mass.

[0062] For blast furnace slag, it is desirable to use blast furnace slag fine powder used in JIS (Japanese Industrial Standard) R5211 "Blast Furnace Cement" or blast furnace slag fine powder conforming to JIS A6206 "Blast Furnace Slag for Concrete". Further, the blast furnace slag has a specific surface area of 2000 to 10000 cm 2 / g, preferably 3500 to 7000 cm 2 / g, is desirably used.

[0063] As the expansion agent, for example, an expansion agent defined in JIS A6202 "Expansion Agent for Concrete" may be used. It is desirable to add the expansion agent at a ratio of 2 to 9% by mass based on the entire hydraulic composition.

[0064] For slaked lime, for example, those defined in JIS R9001 "Lime for Industrial Use" may be used. Further, since quicklime becomes slaked lime when it comes into contact with water, for example, quicklime defined in JIS R9001 "Lime for Industrial Use" can be used instead of slaked lime. In this case, it is advisable to correct the amount of water required when quicklime changes to slaked lime. For fly ash, for example, those conforming to JIS A6201 "Fly Ash for Concrete" may be used.

[0065] For Portland cement, ordinary Portland cement is used. In addition to this, other types of Portland cement such as early-strength Portland cement, super-early-strength Portland cement, moderate-heat Portland cement, low-heat Portland cement, sulfate-resistant Portland cement, etc., as defined in JIS R5210 "Portland Cement", and JIS R5214 "Eco-Cement" can also be used.

[0066] When Portland cement is included in the hydraulic composition, the proportion of Portland cement in the powder other than the calcium-based carbonate compound is 70% by mass or less, and preferably 30% by mass or less.

[0067] Also, when using Portland cement and blast furnace slag or fly ash, those that are pre-mixed, such as JIS R5211 "Blast Furnace Cement", or, for example, JIS R5213 "Fly Ash Cement", can be used alone or in combination.

[0068] Since the calcium-based carbonate compound having the above characteristics is used, the hydraulic composition and the hydraulic composition admixture exhibit good fluidity, and the concrete hardened body can exhibit excellent compressive strength.

[0069] The density of the concrete structure is preferably 0.7 g / cm 3 or more and 2.0 g / cm 3 or less, more preferably 0.8 g / cm 3 or more and 1.8 g / cm 3 or less, and even more preferably 0.9 g / cm 3 or more and 1.6 g / cm 3 or less.

Examples

[0070] Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. The measurement and evaluation of physical properties, etc. were carried out as follows.

[0071] <Evaluation of Calcium Carbonate Compounds> For the calcium carbonate compounds and the like obtained in each production example, the following analyses were carried out. The results of each analysis are shown in Table 1 and Figures 1 and 2.

[0072] (1) BET specific surface area The sample powder pretreated at about 130 °C for about 30 minutes in a nitrogen gas atmosphere using an 8 - stage pre - heating unit (manufactured by MOUNTECH) was measured for BET specific surface area (m 2 / g) by the nitrogen gas adsorption method using a Macsorb HM Model - 1208 (manufactured by MOUNTECH) as a BET specific surface area measuring device.

[0073] (2) Average particle diameter by laser diffraction method 50 mL of ethanol was taken in a 100 - mL beaker, and about 0.2 g of the sample powder was put into the above - mentioned 100 - mL beaker, and ultrasonic treatment (UD - 201 manufactured by Tomy Seiko Co., Ltd.) was carried out for 3 minutes to prepare a dispersion. This dispersion was measured for the volume - based D 50 value as the average particle diameter (μm) using a laser diffraction method - particle size distribution meter (Microtrac HRA Model 9320 - X100 manufactured by Nikkiso Co., Ltd.).

[0074] (3) Apparent specific gravity The apparent specific gravity of the sample powder was measured in accordance with JIS K6220.

[0075] (4) Contents of phosphorus atom, sulfur atom and magnesium atom <ICP - AES method> Weighed 0.2 g of calcium carbonate compound as a sample, moistened it with water, added 10 mL of hydrochloric acid (a solution prepared by mixing concentrated hydrochloric acid and water in a volume ratio of 1:1) using a pipette, and heated and dissolved it. After cooling, it was transferred to a 250 mL volumetric flask, and water was added up to 250 mL to make it up to the mark. 20 mL was taken from this and transferred to a 50 mL volumetric flask, and water was added up to 50 mL to obtain the test liquid for measurement. On the other hand, 20 mL was taken from the 250 mL made-up aqueous solution described above and transferred to a 50 mL volumetric flask, and standard solutions of each element (phosphorus atom, sulfur atom, and magnesium atom) were arbitrarily added additionally to prepare calibration standard solutions with different concentrations. Note that as the standard solutions of each element, 1000 ppm standard solutions for atomic absorption (commercially available) were used.

[0076] The calibration standard solutions with different concentrations obtained by additionally adding each element and the test liquid for measurement were set in the autosampler of an inductively coupled plasma atomic emission spectrometry (ICP - AES) apparatus (manufactured by Hitachi High - Technologies Corporation, "SPECTROBLUE FMS36 type"), and the amount (ppm) of magnesium atoms was measured under the following conditions. <Measurement Conditions> High - frequency output: 1.4 kW Carrier gas (humidified) flow rate: 0.9 L / min Plasma gas flow rate: 13.0 L / min Auxiliary gas flow rate; 1.0 L / min Liquidity: Aqueous solution Number of integrations: 3 times Sample order: For each sample Measurement method: Standard addition method Calibration curve weighting: None Measurement wavelength: Phosphorus atom 177.495 nm, sulfur atom 182.034 nm, magnesium atom 279.553 nm

[0077] (5) Calculation of the ratio of the peak intensity I at 46° (aragonite) to the peak intensity I at 29° (calcite) by XRD measurement a of c for After fixing the sample powder on a specified sample stage with a spatula blade by pressing and adhering, measurement was carried out using an XRD device (MiniFlex600 - C manufactured by Rigaku Corporation), and identification analysis as a crystalline substance was performed. In addition, at the measurement angle 2θ, the peak appearing at about 29° is the main peak of calcite, and the peak appearing at about 46° is the main peak of aragonite. From this, the intensity I a of the 29° (calcite) peak to the intensity I c of the 46° (aragonite) peak (I a / I c ) was determined.

[0078] (6) Scanning electron microscope observation Double - sided tape was attached to an aluminum sample stage, and the sample powder was applied onto it from above like tracing with a spatula blade. After platinum evaporation, a photograph of the particle image of the sample powder was taken at 2000 times magnification using a scanning electron microscope (FE - SEM: S - 4700 manufactured by Hitachi, Ltd.). SEM photographs of the examples and comparative examples are shown in Figs. 1 to 2.

[0079] (Manufacture of calcium - based carbonate compound) [Example 1 - 1] Calcium - based carbonate compound (cubic shape) 8510 g of sodium carbonate reagent (manufactured by Wako Pure Chemical Industries, Ltd.: purity 99.8%) was put into a 220 L capacity SUS container with a baffle plate pre - filled with 100 L of water under stirring to prepare sodium carbonate. On the other hand, 1000 L of seawater (Ca 2+ content: 0.25 g / dL) after removing magnesium hydroxide from the seawater discharged within the premises of Kojima Chemical Industry Co., Ltd. was put into a 2000 L capacity polyethylene container, and 100 L of the above - mentioned sodium carbonate aqueous solution was added all at once under stirring at 25°C, and then the reaction was carried out by continuing stirring for about 30 minutes. Then, it was filtered, washed with about 5 times the amount of water with respect to the solid content, dried at 110°C for 24 hours, pulverized, and a sample powder of the calcium - based carbonate compound was obtained.

[0080] [Example 1 - 2] Calcium - based carbonate compound (cubic shape) After removing magnesium hydroxide from 1000 L of seawater, 12.7 kg of magnesium chloride hexahydrate was added thereto with stirring, and then 100 L of the above-mentioned aqueous sodium carbonate solution was added all at once. Except for this, the same operations as in Example 1-1 were carried out to obtain a sample powder of a calcium-based carbonate compound.

[0081] [Example 1-3] Calcium-based carbonate compound (cubic shape) To 100 L of seawater from which magnesium hydroxide had been removed, 10 L of the above-mentioned aqueous sodium carbonate solution was added all at once with stirring, and then stirring was continued for about 30 minutes. Using the liquid after this reaction as a seed, another 100 L of seawater from which magnesium hydroxide had been removed was added, 10 L of the above-mentioned aqueous sodium carbonate solution was added all at once with stirring, and then stirring was continued for about 30 minutes. This series of operations was continued for a total of 10 times. Except for those operations, the same operations as in Example 1-1 were carried out to obtain a sample powder of a calcium-based carbonate compound.

[0082] [Comparative Example 1-1] Calcium-based carbonate compound (needle shape) 69 80 g of commercially available slaked lime powder (manufactured by Yoshimi Lime Industry Co., Ltd., industrial-grade best-quality slaked lime), 630 g of aragonite seed crystal powder, and 3000 g of disodium hydrogen phosphate dodecahydrate were prepared, and each was put into a 220 L capacity SUS container with a baffle plate filled with 180 L of water in advance and added with stirring to prepare a mixed slurry of raw materials. Then, the temperature was raised to 70 °C, and at that temperature, stirring was carried out at a rotation speed of 150 rpm using a stirrer equipped with 1 stage of turbine blades. An exhaust gas extraction pipe was connected to the exhaust outlet of a boiler for producing steam using LNG as fuel, and while drawing in exhaust gas using a test blower, when measured with a CO2 concentration measuring instrument (XP-3140 manufactured by Shinko Cosmos Electric Co., Ltd.), the CO2 concentration showed 10% by volume. Exhaust gas was introduced into the above-mentioned 220 L capacity SUS container at a rate of 100 L / min using a test blower and reacted for 7 hours. Then, it was filtered, washed with about 5 times the amount of water with respect to the solid content, dried at 110 °C for 24 hours, pulverized, and a sample powder of a calcium-based carbonate compound was obtained.

[0083]

Table 1

[0084] <Evaluation> Using the obtained calcium carbonate compound, the measurement of the P funnel flow-down time, as well as the production and compressive strength test of the cement molded body were carried out. The results are shown in Table 3.

[0085] (Preparation of Cement Milk 1) 2 kg of cement (manufactured by Tokuyama Corporation, "Ordinary Portland Cement (N)") was put into 1600 mL of water in about 20 seconds, and mixed with a stirrer (manufactured by Yamato Scientific Co., Ltd., "Lab Stirrer (LR500B)") for 3 minutes from the start of input. After stopping the stirring and leaving it to stand for 3 minutes, it was stirred 10 times manually with a stirring rod (manufactured by AS ONE Corporation, "Stirring rod (POM-made) φ10×300 mm") to prepare Cement Milk 1.

[0086] (Preparation of Cement Milks 2 to 7) The calcium carbonate compounds of Example 1-1 and Comparative Example 1-1 shown in the following Table 2-1 in the types and amounts were put into 1600 mL of water, stirred manually with the above stirring rod for about 30 seconds, and then stirred at 400 rpm using the stirrer to obtain a mixture. 2 kg of cement (manufactured by Tokuyama Corporation, "Ordinary Portland Cement (N)") was put into this mixture in about 20 seconds, and mixed with the stirrer for 3 minutes from the start of input. After stopping the stirring and leaving it to stand for 3 minutes, it was stirred 10 times manually with the above stirring rod to prepare Cement Milks 2 to 7.

[0087]

Table 2-1

[0088] (Preparation of Cement Milks 8 to 10) Cement Milks 8 to 10 were prepared by performing the same operations as in the preparation of Cement Milks 2 to 7 except that the calcium carbonate compounds of Example 1-2 shown in the following Table 2-2 in the types and amounts were used.

[0089] [Table 2-2]

[0090] (Preparation of Cement Milk 11 to 13) Cement milk 11 to 13 was prepared in the same manner as the preparation of cement milk 2 to 7, except that the calcium carbonate compounds of Examples 1 to 3 in the types and amounts shown in Table 2-3 below were used.

[0091] [Table 2-3]

[0092] (P Funnel Flow Time Test Method) In accordance with the "Test Method for Fluidity of Injection Mortar for Prepacked Concrete (Method Using P Funnel)" (JSCE-F521-1999), the P funnel flow time was measured. With the outlet of the P funnel held with a finger, each of the prepared cement milks was poured up to the marked line of the P funnel (1750 ml), and measurement was started simultaneously with releasing the finger with a stopwatch. The time until the cement milk was discharged from the P funnel was measured.

[0093] (Manufacture of Cement Moldings) [Example 2-1] 400 mL of the prepared cement milk 1 was poured into a cylindrical polyethylene bag (diameter: about 50 mm × length: about 550 mm × thickness: about 0.05 mm) up to the marked line. After injecting air as much as possible and sealing it, it was suspended in a thermostat set at 22°C. It was left for 28 days while suspended in the thermostat, and by curing the contents, a total of 3 cement moldings were manufactured. The obtained cement moldings were cylindrical, with a diameter of about 5 cm and a length of about 20 cm.

[0094] [Examples 2-2 to 2-9 and Comparative Examples 2-1 to 2-4] Cement moldings were manufactured in the same manner as in Example 2-1, except that the cement milks shown in Tables 3-1 to 3-3 below were used.

[0095] (Density) The density was measured in accordance with JIS A 5430:2008 (Apparent Density Test).

[0096] (Compressive Strength Test) The compressive strength of the obtained cement compact was measured in accordance with JIS A 1108:2018 (Test Method for Compression of Concrete).

[0097]

Table 3-1

[0098]

Table 3-2

[0099]

Table 3-3

[0100] In the cement milk using the calcium-based carbonate compound of the example, even when the content of the calcium-based carbonate compound was increased, there was no significant increase in the P funnel flow-down time compared to Comparative Example 2-1 without the calcium-based carbonate compound, and it had good fluidity. On the other hand, in Comparative Examples 2-2 to 2-4, the fluidity decreased significantly as the content of the calcium-based carbonate compound increased.

[0101] Furthermore, in the cement molded body of the example, by blending a calcium-based carbonate compound, the compressive strength was improved compared to Comparative Example 2-1. On the other hand, in Comparative Examples 2-2 to 2-4, even when a calcium-based carbonate compound was blended, the compressive strength decreased compared to the blank Comparative Example 2-1. Although the reason for the decrease in the compressive strength in terms of the blank ratio in Comparative Examples 2-2 to 2-4 is not clear, it is presumed that the calcium-based carbonate compound is needle-shaped and the surface energy has increased, resulting in aggregation and a decrease in the reinforcing effect, or that the needle shape has increased the viscosity of the cement milk, making it difficult for air bubbles to escape, and the cement molded body was obtained with air bubbles remaining.

[0102] From the above, it was found that in the cement milk using the calcium-based carbonate compound of the example, even when the content of the calcium-based carbonate compound was increased, it exhibited fluidity comparable to that of the blank product and excellent compressive strength when formed into a cement molded body.

Claims

1. The calcium-based carbonate compound has a phosphorus atom content of 1000 ppm or less, and a sulfur atom content of 100 ppm or more, and is cubic in shape.

2. The calcium-based carbonate compound according to Claim 1, having an average particle size of 2 μm or more and 25 μm or less as measured by the laser diffraction method.

3. The BET specific surface area is 0.3 m ２ / g or more and 3 m ２ / g or less, and the calcium carbonate compound according to claim 1.

4. The calcium-based carbonate compound according to Claim 1, having an apparent specific gravity of 1 g / mL or more and 2 g / mL or less.

5. The calcium-based carbonate compound according to Claim 1, having a P funnel flow-down time of 7 seconds or more and 10 seconds or less.

6. The calcium-based carbonate compound according to Claim 1, having a magnesium content of 1000 ppm or more.

7. The calcium-based carbonate compound according to Claim 1, wherein the calcium-based carbonate compound is a synthetic calcium-based carbonate compound.

8. The calcium-based carbonate compound according to Claim 1, which is for an inorganic molded body.

9. An inorganic molded body comprising the calcium-based carbonate compound according to any one of Claims 1 to 8.

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