Calcium carbonate compounds and inorganic moldings

Abstract

Provided are calcium carbonate compounds and inorganic molded bodies whose shapes are controlled to have high aspect ratios. [Solution] A calcium carbonate compound having a phosphorus atom content of 1000 ppm or more and 15000 ppm or less, a sulfur atom content of 2000 ppm or less, and an aspect ratio of the average major axis to the average minor axis of 6 or more and 19 or less.

Description

[Technical field]

[0001] The present invention relates to a calcium carbonate compound and an inorganic molded body. [Background technology]

[0002] Inorganic molded bodies are molded bodies that are mostly composed of inorganic substances such as hydraulic materials and siliceous materials, and have properties such as fire resistance, light weight, high strength, and workability, and are therefore widely used as exterior wall materials for houses, roof underlayment materials, eaves ceiling materials, etc. Calcium carbonate is sometimes mixed into inorganic molded bodies for the purpose of reducing carbon dioxide emissions and improving fire resistance.

[0003] On the other hand, due to the recent increase in environmental awareness, attempts are being made to reuse by-products and by-product energy, such as waste, exhaust gas, and waste heat generated secondarily in industrial processes. A technology has been proposed in which carbon dioxide in exhaust gas is used to fix carbon dioxide during the production of calcium carbonate, and this calcium carbonate is incorporated into building materials (WO 2021 / 256484). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 256484 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to improve the functionality of inorganic molded bodies and other objects to which calcium carbonate is added, it is necessary to control the shape of calcium carbonate, particularly to increase the aspect ratio.

[0006] An object of the present invention is to provide a calcium carbonate compound and an inorganic molded body whose shape is controlled so as to have a high aspect ratio. [Means for solving the problem]

[0007] As a result of extensive investigations, the present inventors have found that the above problems can be solved by the following configuration, and have completed the present invention.

[0008] In one embodiment, the present invention comprises: The phosphorus atom content is 1000 ppm or more and 15000 ppm or less, The content of sulfur atoms is 2000 ppm or less, The aspect ratio of the average major axis to the average minor axis is 6 to 19. This relates to calcium carbonate compounds.

[0009] As a result of the inventors' investigations, they have newly discovered that, as factors in forming needle-like or rod-like shapes (hereinafter collectively referred to as "needle-like shapes, etc.") that result in a high aspect ratio during crystal growth of a calcium carbonate compound, phosphorus atoms act as promoting factors for needle-like shapes, etc., and sulfur atoms act as inhibiting factors for needle-like shapes, etc. The inventors have developed this novel finding to complete the present invention. The calcium carbonate compound has phosphorus and sulfur atom contents within specific ranges, so that the shape can be highly controlled and the compound can have a high aspect ratio.

[0010] In this specification, the term "calcium carbonate compound" refers to a compound containing calcium carbonate as a main component, and is a concept that allows the inclusion or coexistence of other subcomponents that may be incorporated during the manufacturing process, etc. The calcium carbonate content in the calcium carbonate compound is preferably 90 mass% or more. The content of calcium carbonate in the calcium carbonate compound can be suitably measured by the disodium ethylenediaminetetraacetate titration method.

[0011] <Disodium ethylenediaminetetraacetate titration method> Weigh out 1 g of calcium carbonate compound as a sample (dried at 105°C for 2 hours), suspend it in 50 mL of water, add 10 mL of hydrochloric acid (a 1:1 mixture of concentrated hydrochloric acid and water by volume), and heat to dissolve. After cooling, transfer to a 250 mL measuring flask and add water to the same amount. Take 5.00 mL from this and add water so that the total volume of the liquid is about 50 mL. Add 5 mL of buffer solution (a solution of 500 g of potassium hydroxide dissolved in water to make 1,000 mL), and then add commercially available Dotite NN diluted powder, and titrate with titration reagent (a solution of about 3.8 g of disodium ethylenediaminetetraacetate dissolved in water to make 1,000 mL). The titration is stopped when the color of the liquid changes from red to blue. Calculate the calcium carbonate content (%) using the following formula.

[0012]

number

[0013] In one embodiment, the content of silicon atoms is preferably 5000 ppm or less. The present inventors have found that silicon atoms are an inhibitor of needle-like formation. By setting the content of silicon atoms within a specific range, the shape controllability of the calcium carbonate compound becomes better, and a high aspect ratio can be efficiently achieved.

[0014] In one embodiment, the total content of phosphorus atoms, silicon atoms and sulfur atoms is preferably 1000 ppm or more and 18000 ppm or less. By setting the total content of the three atoms involved in the shape control of the calcium carbonate compound within the above range, the shape controllability can be further improved.

[0015] In one embodiment, the average particle size of the calcium carbonate compound measured by a laser diffraction method is preferably 1.1 μm or more and 12.5 μm or less in terms of suppressing shrinkage of the heating surface. In one embodiment, the average major axis of the calcium carbonate compound measured by observation with a scanning electron microscope is preferably 0.5 μm or more and 25 μm or less. In another embodiment, the BET specific surface area of ​​the calcium carbonate compound is preferably 1 m 2 / g or more 10m 2 By adjusting the shape control factors in the calcium carbonate compound, these properties can be satisfied alone or in combination.

[0016] In one embodiment, the calcium carbonate compound is preferably a synthetic calcium carbonate compound. By using a synthetic calcium carbonate compound, which is a reaction product of calcium hydroxide and carbon dioxide, as the calcium carbonate compound, carbon dioxide generated secondarily in an industrial process can be reused, which contributes to reducing carbon dioxide emissions in the entire industrial process.

[0017] In one embodiment, the calcium carbonate compound has a high aspect ratio and is therefore suitable as a high-performance additive for inorganic molded bodies.

[0018] In another embodiment, the present invention provides a method for producing a pharmaceutical composition comprising the steps of: The present invention relates to an inorganic formed body containing the calcium carbonate compound.

[0019] By applying a calcium carbonate compound having a high aspect ratio to an inorganic molded body, it is possible to improve the strength and fire resistance, thereby achieving high functionality of the inorganic molded body. [Brief description of the drawings]

[0020] [Figure 1] 1 is a SEM photograph of the calcium carbonate compound of Example 1-1 of the present invention. [Diagram 2] 1 is a SEM photograph of the calcium carbonate compound of Example 1-2 of the present invention. [Diagram 3] 1 is a SEM photograph of the calcium carbonate compound of Example 1-3 of the present invention. [Figure 4] 1 is a SEM photograph of the calcium carbonate compound of Example 1-4 of the present invention. [Diagram 5] 1 is a SEM photograph of a calcium carbonate compound of Comparative Example 1-1 of the present invention. [Figure 6] FIG. 2 is a partial perspective view showing a typical heating tester. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The calcium carbonate compound and the inorganic molded body according to one embodiment of the present invention will be described below, but the present invention is not limited to these embodiments.

[0022] <Calcium carbonate compounds> In the calcium carbonate compound, the content of phosphorus atoms is 1000 ppm or more and 15000 ppm or less. The content of phosphorus atoms is preferably 1200 ppm or more and 12000 ppm or less, more preferably 1500 ppm or more and 10000 ppm or less, even more preferably 2000 ppm or more and 8000 ppm or less, and particularly preferably 2500 ppm or more and 6000 ppm or less. By setting the content of phosphorus atoms to the above-mentioned predetermined amount, it is possible to promote the needle-like formation of the calcium carbonate compound, and to suppress rapid crystal growth, thereby reducing surface unevenness and porosity in the calcium carbonate compound.

[0023] In the calcium carbonate compound, the content of sulfur atoms is 2000 ppm or less. The content of sulfur atoms is preferably 1500 ppm or less, more preferably 1000 ppm or less, even more preferably 800 ppm or less, and particularly preferably 500 ppm or less. Although the content of sulfur atoms is preferably as small as possible, it may be contained in an amount of about 10 ppm. By setting the content of sulfur atoms to the above-mentioned predetermined amount, it is possible to suppress the inhibitory effect of needle formation, etc., and obtain a calcium carbonate compound having a desired high aspect ratio.

[0024] Sulfur atom content C S Phosphorus atom content C (ppm) P (ppm) ratio (C S / C P ) is preferably 0.30 or less, more preferably 0.25 or less, further preferably 0.20 or less, and particularly preferably 0.18 or less. S / C P ) is preferably as small as possible, but may be 0.01 or more. By reducing the amount of sulfur atoms present as an inhibitor of needle-like formation, etc., a calcium carbonate compound having a desired high aspect ratio can be efficiently obtained.

[0025] In calcium carbonate compound, the content of silicon atom is preferably 5000ppm or less, more preferably 4000ppm or less, even more preferably 3000ppm or less, and particularly preferably 2000ppm or less.The content of silicon atom is preferably as small as possible, but may be about 5ppm.By reducing the amount of silicon atom present as an inhibitor of needle-like formation, etc., calcium carbonate compound having a desired high aspect ratio can be efficiently obtained.

[0026] In the calcium carbonate compound, the total content of phosphorus atoms, silicon atoms and sulfur atoms is preferably 1000 ppm or more and 18000 ppm or less, more preferably 1500 ppm or more and 16000 ppm or less, even more preferably 2000 ppm or more and 14000 ppm or less, and particularly preferably 2500 ppm or more and 12000 ppm or less. By setting the total content of the three atoms involved in the shape control of the calcium carbonate compound within the above range, it is possible to further improve the shape controllability.

[0027] The aspect ratio of the average major axis to the average minor axis of the calcium carbonate compound is 6 to 19, preferably 6.5 to 17, and more preferably 7 to 15. The calcium carbonate compound has a specific range of phosphorus and sulfur atom contents, so that the shape can be highly controlled and the calcium carbonate compound can have a high aspect ratio within the range. When the calcium carbonate compound is applied to an inorganic molded body, the calcium carbonate compound with a high aspect ratio effectively functions as a reinforcing material, thereby improving the strength and fire resistance of the inorganic molded body.

[0028] The crystal structure of the calcium carbonate compound may be a calcite type, an aragonite type, or a combination thereof. In order to provide the calcium carbonate compound with the above aspect ratio, it is preferable that the calcium carbonate compound contains at least an aragonite type crystal structure.

[0029] The average particle size of the calcium carbonate compound measured by a laser diffraction method is preferably 1.1 μm to 12.5 μm, more preferably 1.5 μm to 12 μm, and even more preferably 2 μm to 10 μm, which can favorably impart a high aspect ratio to the calcium carbonate compound and improve the dispersibility of the calcium carbonate compound.

[0030] The average major axis of the calcium carbonate compound as observed by a scanning electron microscope is preferably 0.5 μm to 25 μm, more preferably 1 μm to 22 μm, and even more preferably 2 μm to 18 μm, which can favorably impart a high aspect ratio to the calcium carbonate compound and can suppress aggregation between the calcium carbonate compounds or between the calcium carbonate compound and other components.

[0031] The BET specific surface area of ​​the calcium carbonate compound is 1 m 2 / g or more 10m 2 / g or less, and 2 / g or more 9m2 / g or less is more preferable, and 2 / g or more 8m 2 / g or less, it is more preferable that the calcium carbonate compound has a high aspect ratio and the dispersibility of the calcium carbonate compound is improved.

[0032] (Method of producing calcium carbonate compound) The method for synthesizing calcium carbonate compounds is not particularly limited, and known manufacturing methods can be used.Typically, the carbon dioxide gas method is preferred in which carbon dioxide gas is blown into milk of lime (a slurry in which excess slaked lime is added to a saturated aqueous solution of slaked lime) to carbonate it.The carbon dioxide gas used in the carbon dioxide gas method can be the flue gas of a lime calciner installed near a calcium carbonate compound manufacturing plant, or the exhaust gas from a boiler, a waste incinerator, or the like.

[0033] A known method can also be used as a method for imparting a predetermined aspect ratio to a calcium carbonate compound based on the carbon dioxide gas method. Specific examples of the method include a method for producing a calcium carbonate compound in which the amount of carbon dioxide gas is adjusted at each stage in the carbonation process, a method for producing a calcium carbonate compound in which heating is performed at the carbonation stage, a method for producing a calcium carbonate compound in which an acicular light calcium carbonate compound is used as a seed crystal in a slaked lime slurry, carbon dioxide gas is introduced into the slurry, and the seed crystal is grown to a desired particle size by a carbonation reaction, a method for producing a calcium carbonate compound in which an acicular aragonite calcium carbonate compound is added to a slaked lime slurry and a carbonation reaction is performed while stirring with a high stirring power, a method for producing an aragonite crystal-type calcium carbonate compound by adding a phosphoric acid compound, a method for producing an aragonite crystal-type calcium carbonate compound using a slaked lime slurry prepared with an alkaline aqueous solution, and a method for producing an aragonite calcium carbonate compound using a slaked lime slurry prepared with water containing magnesium ions. By using one or more of these methods in combination, a calcium carbonate compound having an aragonite crystal structure can be efficiently produced.

[0034] Among them, a preferred method for producing a calcium carbonate compound having a high aspect ratio is a method for producing a calcium carbonate compound in which needle-shaped synthetic calcium carbonate compound having an aragonite-type crystal structure is used as seed crystals in a slaked lime slurry, carbon dioxide gas is introduced into the slurry, and the seed crystals are grown to a desired particle size by a carbonation reaction (hereinafter also referred to as the "seed crystal method").

[0035] In the seed crystal method, the amount of seed crystals to be mixed is preferably 1 part by mass or more and 30 parts by mass or less, more preferably 5 parts by mass or more and 20 parts by mass or less, and even more preferably 8 parts by mass or more and 15 parts by mass or less, per 100 parts by mass of slaked lime (calculated as CaO).

[0036] In the seed crystal method, the concentration of carbon dioxide gas varies depending on the type of exhaust gas generated from each combustion engine, but considering carbonation efficiency, it is preferably 1% by volume or more, more preferably 5% by volume or more, and even more preferably 10% by volume or more. The flow rate of carbon dioxide gas is, considering carbonation efficiency and production capacity, 10 L / min to 200 L / min per 10 kg of raw material CaO charged. below is preferable, and 30L / min to 150L / min below More preferably, 60L / min to 120L / min below is more preferred.

[0037] In the seed crystallization method, the carbonation temperature (the slurry temperature) is preferably from 40°C to 100°C, more preferably from 50°C to 90°C, and even more preferably from 60°C to 80°C.

[0038] In the seed crystal method, it is preferable to proceed with carbonation in the presence of a phosphate. The phosphate is not particularly limited, but examples thereof include phosphoric acid, sodium dihydrogen phosphate anhydrous, sodium dihydrogen phosphate monohydrate, sodium dihydrogen phosphate dihydrate, disodium hydrogen phosphate dodecahydrate, potassium dihydrogen phosphate anhydrous, and ammonium dihydrogen phosphate anhydrous.

[0039] In the seed crystal method, the amount of phosphate to be mixed is preferably 1 to 25 parts by mass, more preferably 4 to 18 parts by mass, and even more preferably 6 to 12 parts by mass, relative to 100 parts by mass of slaked lime (calculated as CaO). By adjusting the amount to such a range, the content of phosphorus atoms in the obtained calcium carbonate compound can be adjusted to a predetermined range.

[0040] Although the method for adjusting the content of sulfur atoms in the calcium carbonate compound to fall within the above range is not particularly limited, examples thereof include a method in which a sulfate compound is added to control the aspect ratio so as not to become too large (e.g., so as not to exceed 20), and the amount of sulfate compound added is reduced or no sulfate compound is added to control the aspect ratio to a predetermined value, and a method in which sulfate compounds in the raw material for slaked lime are dissolved and removed with a strong alkali.

[0041] Although the method of making the content of silicon atoms in the calcium carbonate compound fall within the above range is not particularly limited, for example, a silica compound may be added to control the aspect ratio so that it does not become too large (for example, so that it does not exceed 20), and a method of reducing the amount of silica compound added or not adding silica compound to control the aspect ratio to a predetermined aspect ratio, or a method of adjusting the amount of fuel-derived impurities that may be contained in the slaked lime by appropriately selecting the type of fuel for calcining limestone, etc. For example, if heavy oil is used as the calcination fuel, the amount of impurities (sulfur atoms) derived from sulfuric acid will increase, while if coal is used as the fuel, the amount of impurities (silicon atoms) derived from coal ash will increase. In order to reduce the content of sulfur atoms and silicon atoms derived from impurities, a method of burning liquefied natural gas (LNG) or hydrogen, a method of using an electric furnace, etc. can be mentioned.

[0042] The produced calcium carbonate compound may be filtered and dried to obtain a powder, or may be used as a calcium carbonate compound source in the form of a slurry or cake without being filtered or dried.

[0043] In addition to the carbon dioxide gas method, a waste seawater utilization method in which an alkaline agent such as magnesium hydroxide is added to waste seawater (residue after removing magnesium) generated when magnesium hydroxide is produced by adding slaked lime or the like to seawater and then carbon dioxide gas is blown into the waste seawater is also preferable from the viewpoints of waste utilization and carbon dioxide reduction. Furthermore, as described above, in the process of producing magnesium hydroxide from seawater, calcium-based carbonate compounds by-produced in the process of removing carbonates in seawater and seawater residue mainly composed of magnesium hydroxide can also be used as the calcium-based carbonate compound source.

[0044] <Applications of calcium carbonate compounds> The use of the calcium carbonate compound is not particularly limited. For example, it is suitable as a high-performance material for inorganic molded bodies, such as building materials, a filler for resins, etc. Hereinafter, an embodiment in which the calcium carbonate compound is used for an inorganic molded body will be described.

[0045] <Inorganic molded body> The inorganic molded body preferably contains a hydraulic material, a siliceous material, a reinforcing fiber material, and a calcium carbonate compound having a predetermined aspect ratio.

[0046] (hydraulic material) Examples of hydraulic materials include cementitious materials, gypsum, lime, slag, etc. Examples of cementitious materials include commonly used cements, such as ordinary Portland cement, high-early-strength cement, moderate-heat cement, fly ash cement, blast furnace slag cement, and alumina cement. Examples of gypsum include anhydrous gypsum, hemihydrate gypsum, dihydrate gypsum, etc. Examples of slag include blast furnace slag, converter slag, etc. 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 materials constituting the inorganic molded body. By setting the content of the hydraulic material within the above range, it is possible to improve the physical properties such as bending strength and peel strength of the inorganic molded body, and to suppress the increase in bulk specific gravity of the inorganic molded body, thereby improving workability during construction.

[0048] (siliceous material) Examples of siliceous materials include silica sand, silica powder, silica fume, fly ash, diatomaceous earth, and layered silicates (e.g., mica, talc, kaolin, and bentonite). , Wa SiO, such as lastonite, lightweight aggregates (e.g. fly ash balloons, perlite, shirasu balloons, glass foam, etc.), etc. 2 These siliceous materials can be used alone or in combination of two or more. Talc, mica, and wollastonite can also be used as reinforcing fiber materials, which will be 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 materials constituting the inorganic molded body. If the content of the siliceous material is within the above range, it becomes possible to set the bending strength, bulk density, water absorption rate, dimensional stability, etc. of the inorganic molded body within the desired range. In addition, as the siliceous material, perlite, fly ash balloons, shirasu balloons, etc., having a unit volume mass of 0.5 g / cm are preferable. 3 When mixing the following lightweight aggregates, in order to prevent the bulk density from becoming too light, which would weaken strength such as bending strength and peel strength, it is preferable to use other siliceous materials in combination so that the content of lightweight aggregate is 20 mass% or less, based on the total amount of materials constituting the inorganic molded body.

[0050] (Reinforcing fiber materials) Examples of reinforcing fiber materials that can be used include pulps such as softwood pulp, hardwood pulp, pulps fibrillated with these pulps, and pulp made 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 and toughness of the inorganic molded body, 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 materials constituting the inorganic molded body. By setting the content of the reinforcing fiber material within the above range, it is possible to suppress the fibers from protruding from the surface of the inorganic molded body while exerting a sufficient reinforcing effect, thereby improving 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, it is preferable to use another reinforcing fiber material in combination so that the content is 10% by mass or less, based on the total amount of materials constituting the inorganic molded body, in order to improve the smoothness of the inorganic molded body.

[0052] (Calcium carbonate compounds) As the calcium carbonate compound, the above-mentioned calcium carbonate compounds can be suitably used.

[0053] The content of the calcium 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 inorganic molded body. By blending the calcium carbonate compound having low thermal conductivity in the above-mentioned content range, the strength and fire resistance of the inorganic molded body can be improved.

[0054] (optional ingredient) In addition to the above materials, in order to impart various functions to the inorganic molded body, various materials such as resin hollow bodies, wood chips, wood powder, resin powder, defoamers, flocculants, water repellents, thickeners (methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, etc.), dispersants, etc. can be mixed into the inorganic molded body depending on the purpose. It is also possible to appropriately add recycled materials obtained by crushing scraps generated during processing of the inorganic molded body.

[0055] The bulk density of the inorganic molded body is 0.7 g / mL or more and 1.4 g / cm 3 It is preferable that the concentration is 0.8 g / mL or more and 1.2 g / cm or less. 3 More preferably, it is 0.9 g / mL to 1.1 g / cm 3 It is even more preferable that:

[0056] (Method for producing inorganic molded body) The method for producing the inorganic molded body according to this embodiment is not particularly limited, and generally used methods such as papermaking, extrusion molding, flow-on molding, pouring molding, and press (compression) molding can be used. The inorganic molded body can be obtained by subjecting a green sheet molded by these methods to a patterning process such as press dehydration or embossing, and then curing the green sheet at room temperature, steam curing, autoclave curing, etc. Furthermore, the green sheet may be dried, and shaped or painted as necessary.

[0057] (Uses of inorganic molded bodies) The use of the inorganic molded body is not particularly limited, and it can be suitably used as a performance maintaining material such as a wall material, a floor material, a roofing material, various boards, external decorative members, interior and exterior finishing materials such as fittings, a sealing material, a heat insulating material, a sound absorbing material, a waterproofing material, etc. The inorganic molded body is preferably a cement-based molded body containing a cementitious material, and more preferably a calcium silicate molded body. Among them, the molded body is more preferably a molded board. EXAMPLES

[0058] Hereinafter, the present invention will be described in detail using examples. However, the present invention is not limited to the following examples as long as it does not exceed the gist thereof. The measurement and evaluation of physical properties and the like were carried out as follows.

[0059] <Evaluation of calcium-based carbonate compounds> Regarding the calcium-based carbonate compounds obtained in each production example and the like, the following analyses were performed. The results of each analysis are shown in Table 1 and Figures 1 to 5.

[0060] (1) Contents of phosphorus atom, sulfur atom and silicon atom <ICP-AES method> Weighed 0.2 g of the calcium-based 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 at 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. From this, 20 mL was taken and placed in a 50 mL volumetric flask, and water was added up to 50 mL to obtain a test solution for measurement. On the other hand, 20 mL was taken from the 250 mL made-up aqueous solution and placed in a 50 mL volumetric flask, and standard solutions of each element (phosphorus atom, sulfur atom and silicon atom) were arbitrarily added 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.

[0061] The calibration standard solutions with different concentrations to which each element was added and the test solution 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 amounts (ppm) of phosphorus atom, sulfur atom and silicon atom were 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, silicon atom 251.612 nm

[0062] (2) Sulfur atom content C S Phosphorus atom content C (ppm) P (ppm) ratio (C S / C P ) The sulfur atom content C obtained in (1) above S (ppm) and phosphorus atom content C P (ppm) to ratio (C S / C P ) was calculated.

[0063] (3) BET specific surface area The sample powder was pretreated in a nitrogen gas atmosphere at approximately 130°C for approximately 30 minutes using an 8-unit preheat unit (MOUNTECH), and the BET specific surface area (m2) was measured by nitrogen gas adsorption using a Macsorb HM Model-1208 (MOUNTECH) BET specific surface area measuring device. 2 / g) was measured.

[0064] (4) Average particle size by laser diffraction method 50 mL of ethanol was placed in a 100 mL beaker, and about 0.2 g of the sample powder was placed in the 100 mL beaker. The dispersion was subjected to ultrasonic treatment (Tomy Seiko UD-201) for 3 minutes to prepare a dispersion. The volumetric D of this dispersion was measured using a laser diffraction particle size distribution analyzer (Nikkiso Microtrac HRA Model 9320-X100). 50 The value was measured as the average particle size (μm).

[0065] (5) Calculation of average major axis, average minor axis and aspect ratio by scanning electron microscope observation Double-sided tape was attached to an aluminum sample stage, and the sample powder was applied on top of it by tracing it with a spatula. After platinum deposition, the particle images of the sample powder were photographed at 2,000 times magnification using a scanning electron microscope (FE-SEM: S-4700 manufactured by Hitachi, Ltd.). Figures 1 to 5 show SEM images of the examples and comparative examples. For the obtained SEM images, 20 particles were randomly selected from the images using image analysis software (Image J), ​​and the average values ​​of the major axis, minor axis (the span when an axis perpendicular to the major axis is taken at the center of the major axis) and aspect ratio (the ratio of the major axis to the minor axis) of the primary particles were calculated.

[0066] <Production of calcium carbonate compounds> [Example 1-1] Calcium carbonate compound (aspect ratio 6.6) 7000g of quicklime powder produced by the co-firing of limestone and coal was added to 50L of water at 70°C under stirring and slaked for 1 hour to prepare milk of lime. This milk of lime (calculated as CaO) was added to 6980g of aragonite seed crystal powder, 630g of aragonite seed crystal powder, and 500g of disodium hydrogen phosphate dodecahydrate under stirring in a 220L stainless steel vessel with baffles and filled with 180L of water to prepare a mixed slurry of the raw materials. The temperature was then raised to 70°C, and the mixture was stirred at a speed of 150rpm using a stirrer equipped with one turbine blade at that temperature. A flue gas extraction pipe was connected to the exhaust outlet of a steam production boiler that uses LNG as fuel, and the exhaust gas was drawn in using a test blower while CO 2 When measured using a concentration meter (Shin Cosmos Electric Co., Ltd. XP-3140), CO 2 The concentration was 10% by volume. Exhaust gas was introduced into the 220-liter SUS container described above at a speed of 100 L / min using a test blower and reacted for 7 hours. After that, it was filtered, washed with about 5 times the amount of water relative to the solid content, dried at 110°C for 24 hours, and pulverized to obtain a sample powder of calcium carbonate compound.

[0067] [Example 1-2] Calcium carbonate compound (aspect ratio 8.6) A sample powder of calcium carbonate compound was obtained by the same procedure as in Example 1-1, except that 6,980 g of commercially available slaked lime powder (Yoshimi Sekki Kogyo Co., Ltd., industrial best quality slaked lime) (calculated as CaO), 630 g of aragonite seed crystal powder, and 1,500 g of disodium hydrogen phosphate dodecahydrate were added.

[0068] [Example 1-3] Calcium carbonate compound (aspect ratio 10.4) A sample powder of calcium carbonate compound was obtained by the same procedure as in Example 1-1, except that 6,980 g of commercially available slaked lime powder (Yoshimi Sekki Kogyo Co., Ltd., industrial best quality slaked lime) (calculated as CaO), 630 g of aragonite seed crystal powder, and 500 g of disodium hydrogen phosphate dodecahydrate were added.

[0069] [Example 1-4] Calcium carbonate compound (aspect ratio 18.2) 7000 g of commercially available quicklime (granular best quality quicklime, manufactured by Yoshimi Sekki Kogyo Co., Ltd.) was added to 50 L of water at 70°C under stirring and slaked for 1 hour to prepare milk of lime. The same procedure as in Example 1-1 was carried out to obtain a sample powder of a calcium carbonate compound, except that the milk of lime was 3400 g in terms of CaO, 310 g of the sample powder of a calcium carbonate compound obtained in Example 1-3 was used as aragonite seed crystals, and 240 g of disodium hydrogen phosphate dodecahydrate was used.

[0070] [Comparative Example 1-1] Calcium carbonate compound (aspect ratio 5.2) A sample powder of calcium carbonate compound was obtained by the same procedure as in Example 1-1, except that 6,980 g of commercially available slaked lime powder (Yoshimi Seki Lime Industry Co., Ltd., industrial best quality slaked lime) (calculated as CaO), 630 g of aragonite seed crystal powder, and 500 g of disodium hydrogen phosphate dodecahydrate were added, and then 125 g of sodium sulfate was further added.

[0071] [Comparative Example 1-2] Calcium carbonate compound (aspect ratio 5.3) A sample powder of calcium carbonate compound was obtained by the same procedure as in Example 1-1, except that 6,980 g of commercially available slaked lime powder (Yoshimi Sekki Kogyo Co., Ltd., industrial best quality slaked lime) (calculated as CaO), 630 g of aragonite seed crystal powder, and 3,000 g of disodium hydrogen phosphate dodecahydrate were added.

[0072] [Table 1]

[0073] <Production of Inorganic Molded Body> Inorganic molded bodies were manufactured by the papermaking method and extrusion molding method according to the following procedures. The amounts of the components used are all shown in "parts by mass" unless otherwise specified. In the table below, "-" indicates that the corresponding component was not used.

[0074] [Example 2-1] Production of inorganic molded body by papermaking method The materials shown in Table 2 below were put into a plastic container and mixed with stirring to obtain a raw material slurry. The calcium carbonate compound of Example 1-1 was used as the calcium carbonate compound. The raw material slurry was divided and put into a filter covered with felt, and a laminate (long side 28 mm x short side 24 mm x thickness 14 mm) was produced while performing suction filtration with a vacuum pump. The laminate was removed from the filter and subjected to dehydration pressing. The thickness after pressing was 13 mm. After autoclave curing (curing pressure (gauge pressure) 9 kgf; curing time 12 hours), the pressed body was dried in a dryer (105°C) for 24 hours. Both sides were polished with a sander to adjust the thickness to 12 mm, and an inorganic molded body was obtained.

[0075] [Example 2-2] Production of inorganic molded body by papermaking method An inorganic formed body was obtained in the same manner as in Example 2-1, except that the calcium carbonate compound of Example 1-2 was used as the calcium carbonate compound.

[0076] [Example 2-3] Production of inorganic molded body by papermaking method An inorganic formed body was obtained in the same manner as in Example 2-1, except that the calcium carbonate compound of Example 1-3 was used as the calcium carbonate compound.

[0077] [Example 2-4] Production of inorganic molded body by papermaking method An inorganic formed body was obtained in the same manner as in Example 2-1, except that the calcium carbonate compound of Example 1-4 was used as the calcium carbonate compound.

[0078] [Comparative Example 2-1] Production of inorganic molded body by papermaking method An inorganic formed body was obtained in the same manner as in Example 2-1, except that the calcium carbonate compound of Comparative Example 1-1 was used as the calcium carbonate compound.

[0079] [Comparative Example 2-2] Production of inorganic molded body by papermaking method An inorganic formed body was obtained in the same manner as in Example 2-1, except that the calcium carbonate compound of Comparative Example 1-2 was used as the calcium carbonate compound.

[0080] [Comparative Example 2-3] Production of inorganic molded body by papermaking method An inorganic molding was obtained in the same manner as in Example 2-1, except that a calcium carbonate compound having an aspect ratio of 25 was used as the calcium carbonate compound. However, the calcium carbonate compound was broken during molding and could not maintain its original shape, so no evaluation was performed.

[0081] <Evaluation of inorganic molded bodies> The inorganic molded bodies produced by the papermaking method in the examples and comparative examples were evaluated as follows. The results are shown in Table 2.

[0082] (bulk density) The bulk density was measured in accordance with JIS A 5430.

[0083] (Heating test) The heating test was carried out with the following equipment and procedure. Figure 6 is a schematic partial perspective view of the heating tester. As shown in Figure 6, an electric heater was used as the heat source, and fireproof material was installed between the test specimen and the heat source so that the temperature could be stabilized at around 900°C, and a thermocouple was used to measure the temperature of the back side of the test specimen. Specifically, an electric heater (1.2 kW heater) was fixed as the heat source equipment so that the distance between the heating surface of the test specimen and the heat source was about 70 mm.

[0084] The test procedure was as follows. (1) A scrap board was placed and preheating was performed up to 902°C, after which heating was performed once. (2) The test specimen was inserted after the heated surface had cooled below 200°C. (3) A thermocouple was placed in the center of the back surface of the test specimen (top surface in the figure), and a calcium silicate plate (approximately 30 mm x 70 mm) and a weight were placed on top and fixed in place. (4) Heating was started, and the specimen was left for a specified time (45 minutes), after which the temperatures of the front and back sides were recorded with a data logger. During this time, the temperature of the electric heater was set to 902°C on the heating side, and was controlled with a temperature controller with a lower limit of 900°C. The data logger also measured the temperature every 10 seconds, and the data was recorded at this interval. (5) After the test was completed, the test specimens were removed and the following items were measured (each item was also measured before the test): Dimensions: The length and width of the back surface and the heated surface were measured with a caliper. The area of ​​the heated surface (mm 2 ) was calculated, and the heating surface shrinkage (%) was calculated based on the following formula: Heating surface shrinkage (%) = {|S 1 -S 0 | / S 0}×100 (In the formula, S 0 is the area of ​​the heated surface before the test, and S 1 is the area of ​​the heated surface after the test.)

[0085] [Table 2]

[0086] The inorganic molded body of the embodiment was superior to the comparative example in both the heated surface shrinkage and the back surface temperature rise, and showed good fire resistance. In addition, the inorganic molded body of the embodiment did not develop cracks after heating (not shown).

[0087] [Example 3-1] Production of inorganic molded body by extrusion molding method The materials shown in Table 3 below were put into an Omnimixer and the raw materials were dry-mixed for 3 minutes. The calcium carbonate compound of Example 1-1 was used as the calcium carbonate compound. Next, water was added and wet-mixed for 2 minutes. The raw materials after wet mixing were kneaded with an Ishikawa extruder, and then extrusion-molded with the Ishikawa extruder. This produced a molded body (long side 600 mm x short side 190 mm x thickness 13 mm). After obtaining the molded body, it was put into a thermostatic chamber set at 60°C / 98% and subjected to primary curing, and then the pressure was increased to 9 kgf and autoclave curing was performed for 12 hours. Both sides of the molded body were polished with a sander to make the thickness 12 mm, producing an inorganic molded body.

[0088] [Example 3-2] Production of inorganic molded body by extrusion molding method An inorganic formed body was obtained in the same manner as in Example 3-1, except that the calcium carbonate compound of Example 1-2 was used as the calcium carbonate compound.

[0089] [Example 3-3] Production of inorganic molded body by extrusion molding method An inorganic formed body was obtained in the same manner as in Example 3-1, except that the calcium carbonate compound of Example 1-3 was used as the calcium carbonate compound.

[0090] [Example 3-4] Production of inorganic molded body by extrusion molding method An inorganic formed body was obtained in the same manner as in Example 3-1, except that the calcium carbonate compound of Example 1-4 was used as the calcium carbonate compound.

[0091] [Comparative Example 3-1] Production of inorganic molded body by extrusion molding method An inorganic formed body was obtained in the same manner as in Example 3-1, except that the calcium carbonate compound of Comparative Example 1-1 was used as the calcium carbonate compound.

[0092] [Comparative Example 3-2] Production of inorganic molded body by extrusion molding method An inorganic formed body was obtained in the same manner as in Example 3-1, except that the calcium carbonate compound of Comparative Example 1-2 was used as the calcium carbonate compound.

[0093] [Comparative Example 3-3] Production of inorganic molded body by extrusion molding method An inorganic molding was obtained in the same manner as in Example 3-1, except that a calcium carbonate compound having an aspect ratio of 25 was used as the calcium carbonate compound. However, the calcium carbonate compound was broken during molding and could not maintain its original shape, so no evaluation was performed.

[0094] <Evaluation of inorganic molded bodies> The inorganic molded bodies produced by extrusion molding in the Production Examples and Comparative Production Examples were evaluated as follows. The results are shown in Table 3.

[0095] (bulk density) The bulk density was measured in accordance with JIS A 5430.

[0096] (3-point bending test) The three-point bending test was performed in accordance with JIS A 5430. The results were used to calculate the strength (N / mm 2 ) was decided.

[0097] (Heating test) In addition to the measurements made in the same manner as in the papermaking method, after the completion of the above (5) test, the test specimen was taken out and the following items were measured (each item was also measured before the test). Warpage: The specimen was placed on a steel plate, and the height of the center of each side of the specimen from the steel plate was measured with a thickness gauge, and the average value (mm) was calculated. This average value was taken as the warpage after heating (mm).

[0098] [Table 3]

[0099] In the inorganic molding of the embodiment, the strength and heating surface shrinkage , rear surface temperature rise The inorganic molded bodies of the examples showed good strength and fire resistance, with both the warpage after heating being equal to or greater than those of the comparative examples. Furthermore, no cracks were generated after heating in the inorganic molded bodies of the examples (not shown).

Claims

1. The content of phosphorus atoms is 1000 ppm or more and 15000 ppm or less, The content of sulfur atoms is 2000 ppm or less, The aspect ratio of the average major axis to the average minor axis is 6 or more and 19 or less. Calcium carbonate compound.

2. 2. The calcium carbonate compound according to claim 1, having a silicon atom content of 5000 ppm or less.

3. 3. The calcium carbonate compound according to claim 2, wherein the total content of phosphorus atoms, silicon atoms and sulfur atoms is 1,000 ppm or more and 18,000 ppm or less.

4. The content C of sulfur atoms Ｓ The content C of the phosphorus atoms (ppm) Ｐ (ppm) (C Ｓ / C Ｐ 2. The calcium carbonate compound according to claim 1, wherein the calcium carbonate content is 0.30 or less.

5. 2. The calcium carbonate compound according to claim 1, having an average particle size of 1.1 μm or more and 12.5 μm or less as measured by a laser diffraction method.

6. 2. The calcium carbonate compound according to claim 1, having an average major axis of 0.5 μm or more and 25 μm or less as measured by scanning electron microscopy.

7. BET specific surface area: 1 m ２ / g or more 10m ２ The calcium carbonate compound according to claim 1, wherein the calcium carbonate content is 1 / g or less.

8. The calcium carbonate compound according to claim 1 , wherein the calcium carbonate compound is a synthetic calcium carbonate compound.

9. The calcium carbonate compound according to any one of claims 1 to 8, which is for use in inorganic molded bodies.

10. An inorganic formed body comprising the calcium carbonate compound according to any one of claims 1 to 8.

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