Calcium-based carbonate compound and inorganic molded body

Abstract

To provide a calcium-based carbonate compound with a shape controlled to have a high aspect ratio and to provide an inorganic molded body.SOLUTION: A calcium-based carbonated compound has 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 long axis to the average short axis of 6 or more and 19 or less.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. For the purpose of reducing carbon dioxide emissions and improving fire resistance, calcium carbonate may be blended into the inorganic molded body.

[0003] On the other hand, due to the increasing environmental awareness in recent years, attempts have been made to reuse by-products and by-product energy such as waste, exhaust gas, and waste heat generated secondarily in industrial processes. A technique has been proposed in which carbon dioxide is fixed by using carbon dioxide in exhaust gas during the production of calcium carbonate, and this calcium carbonate is blended into building materials (International Publication No. 2021 / 256484).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] For the purpose of enhancing the functionality of calcium carbonate-containing objects such as inorganic molded bodies, control of the shape of calcium carbonate, particularly an increase in the aspect ratio, is required.

[0006] An object of the present invention is to provide a calcium-based carbonate compound and an inorganic molded body whose shapes are controlled to have a high aspect ratio.

Means for Solving the Problems

[0007] As a result of intensive studies, 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 relates to 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. The present invention relates to a calcium-based carbonate compound.

[0009] As a result of studies by the present inventors, as factors for acicularization or rod-shaped formation (hereinafter also collectively referred to as "acicularization, etc.") that results in a high aspect ratio during crystal growth of the calcium-based carbonate compound, it has been newly found that phosphorus atoms act as promoters for acicularization, etc., and sulfur atoms act as inhibitors for acicularization, etc. The present inventors have developed this new finding to complete the present invention. Since the calcium-based carbonate compound has the content of phosphorus atoms and sulfur atoms within a specific range, its shape can be highly controlled and it can have a high aspect ratio.

[0010] In the present 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 sub-components that can be incorporated in the manufacturing process or the like. The content of calcium carbonate 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 employed.

[0011] <Disodium Ethylenediaminetetraacetate Titration Method> Weigh 1 g of a calcium 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 at 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 a 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.

[0012]

Number

[0013] In one embodiment, it is preferable that the silicon atom content is 5000 ppm or less. The inventors have found that the silicon atom is an inhibitory factor such as needle formation. By setting the silicon atom content within a specific range, the shape controllability of the calcium carbonate compound becomes better, and a high aspect ratio can be achieved efficiently.

[0014] In one embodiment, it is preferable that the total content of phosphorus atoms, silicon atoms and sulfur atoms is 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, further improvement in shape controllability can be achieved.

[0015] In one embodiment, the average particle diameter of the calcium carbonate compound by the laser diffraction method is preferably 1.1 μm or more and 12.5 μm or less from the viewpoint of suppressing shrinkage of the heating surface. In one embodiment, the average major axis diameter of the calcium carbonate compound observed by a scanning electron microscope is preferably 0.5 μm or more and 25 μm or less. Further, in one embodiment, the BET specific surface area of the calcium carbonate compound is preferably 1 m 2 / g or more and 10 m 2 / g or less. By adjusting the shape control factors in the calcium carbonate compound, these characteristics 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 gas (carbon dioxide), the carbon dioxide generated secondarily in the industrial process can be reused, contributing to the reduction of carbon dioxide emissions throughout the industrial process.

[0017] In one embodiment, since the calcium carbonate compound has a high aspect ratio, it is suitable as a high-functional material for the inorganic molded body.

[0018] In other embodiments of the present invention, the present invention relates to an inorganic molded body containing the calcium carbonate compound.

[0019] By applying a calcium carbonate compound with a high aspect ratio to an inorganic molded body, the strength and fire resistance can be improved, and the high functionality of the inorganic molded body can be achieved.

Brief Description of Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0021] 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.

[0022] <Calcium-based carbonate compound> In the calcium-based carbonate compound, the content of phosphorus atoms is 1000 ppm or more and 15000 ppm or less. The content of the phosphorus atoms is preferably 1200 ppm or more and 12000 ppm or less, more preferably 1500 ppm or more and 10000 ppm or less, still 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 predetermined amount, it is possible to promote the acicularization of the calcium-based carbonate compound and suppress rapid crystal growth, thereby reducing surface irregularities and porosity in the calcium-based carbonate compound.

[0023] In the calcium-based carbonate compound, the content of sulfur atoms is 2000 ppm or less. The content of the sulfur atoms is preferably 1500 ppm or less, more preferably 1000 ppm or less, still 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 contain about 10 ppm. By setting the content of sulfur atoms to the predetermined amount, it is possible to suppress the inhibitory action such as acicularization and obtain a calcium-based carbonate compound having a desired high aspect ratio.

[0024] Content C of sulfur atoms S (ppm) Content C of phosphorus atoms P (ppm) Ratio (C S / C P ) is preferably 0.30 or less, more preferably 0.25 or less, still more preferably 0.20 or less, and particularly preferably 0.18 or less. Note that although the smaller the ratio (C S / C P ) is, the more preferable it is, it may also be 0.01 or more. By reducing the abundance of sulfur atoms as an inhibitory factor such as needle formation, a calcium-based carbonate compound having a desired high aspect ratio can be efficiently obtained.

[0025] In the calcium-based carbonate compound, the content of silicon atoms is preferably 5000 ppm or less, more preferably 4000 ppm or less, still more preferably 3000 ppm or less, and particularly preferably 2000 ppm or less. Note that although the smaller the content of silicon atoms is, the more preferable it is, it may contain about 5 ppm. By reducing the abundance of silicon atoms as an inhibitory factor such as needle formation, a calcium-based carbonate compound having a desired high aspect ratio can be efficiently obtained.

[0026] In the calcium-based 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, still 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-based carbonate compound within the above range, further improvement in shape controllability can be achieved.

[0027] The aspect ratio of the average major axis to the average minor axis of the calcium-based carbonate compound is 6 or more and 19 or less, preferably 6.5 or more and 17 or less, and more preferably 7 or more and 15 or less. In the calcium-based carbonate compound, since the contents of phosphorus atoms and sulfur atoms are within a specific range, the shape can be highly controlled, and it can have a high aspect ratio within the above range. Further, when the calcium-based carbonate compound is applied to an inorganic molded body, the calcium-based carbonate compound having a high aspect ratio effectively functions as a reinforcing material, so that the strength and fire resistance of the inorganic molded body can be improved.

[0028] As the crystal structure of the calcium-based carbonate compound, a calcite type, an aragonite type, or a combination thereof can be preferably employed. From the viewpoint of imparting the aspect ratio to the calcium-based carbonate compound, it is preferable to contain at least an aragonite-type crystal structure.

[0029] The average particle diameter of the calcium-based carbonate compound by the laser diffraction method is preferably 1.1 μm or more and 12.5 μm or less, more preferably 1.5 μm or more and 12 μm or less, and even more preferably 2 μm or more and 10 μm or less. Thereby, a high aspect ratio can be preferably imparted to the calcium-based carbonate compound, and the dispersibility of the calcium-based carbonate compound can also be improved.

[0030] The average major axis of the calcium-based carbonate compound observed by a scanning electron microscope is preferably 0.5 μm or more and 25 μm or less, more preferably 1 μm or more and 22 μm or less, and even more preferably 2 μm or more and 18 μm or less. Thereby, a high aspect ratio can be preferably imparted to the calcium-based carbonate compound, and aggregation of the calcium-based carbonate compounds with each other or between the calcium-based carbonate compound and other components can be suppressed.

[0031] The BET specific surface area of the calcium-based carbonate compound is preferably 1 m 2 / g or more and 10 m 2 / g or less, more preferably 2 m 2 / g or more and 9 m2 It is more preferably below / g, and 3 m 2 / g or more and 8 m 2 It is even more preferably below / g. Thereby, a high aspect ratio can be suitably imparted to the calcium-based carbonate compound, and the dispersibility of the calcium-based carbonate compound can be improved.

[0032] (Method for producing calcium-based carbonate compound) The synthesis method of the calcium-based carbonate compound is not particularly limited, and a known production method can be adopted. Typically, the carbon dioxide gas method of blowing carbon dioxide gas into lime milk (a slurry obtained by further adding excess slaked lime to a saturated aqueous solution of slaked lime) for carbonation is preferred. As the carbon dioxide gas used in the carbon dioxide gas method, the flue gas of a lime calcination furnace installed in the vicinity of a calcium-based carbonate compound production plant, the exhaust gas of a boiler, a garbage incinerator, etc. can be utilized.

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

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

[0035] In the seed crystal method, the blending amount of the seed crystal 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 still more preferably 8 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of slaked lime (in terms of 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. However, considering the carbonation efficiency, it is preferably 1% by volume or more, more preferably 5% by volume or more, and still more preferably 10% by volume or more. The flow rate of carbon dioxide gas is preferably 10 L / min or more and 200 L / min per 10 kg of the charged raw material CaO content, considering the carbonation efficiency and production capacity. The following is preferably 30 L / min or more and 150 L / min The following is more preferably 60 L / min or more and 120 L / min The following is still more preferably.

[0037] In the seed crystal method, the carbonation temperature (the slurry temperature) is preferably 40°C or more and 100°C or less, more preferably 50°C or more and 90°C or less, and still more preferably 60°C or more and 80°C or less.

[0038] In the seed crystal method, it is preferable to allow a phosphate to coexist and proceed with carbonation. Although the phosphate is not particularly limited, examples thereof include phosphoric acid, sodium dihydrogen phosphate anhydrate, sodium dihydrogen phosphate monohydrate, sodium dihydrogen phosphate dihydrate, disodium hydrogen phosphate dodecahydrate, potassium dihydrogen phosphate anhydrate, ammonium dihydrogen phosphate anhydrate, and the like.

[0039] In the crystallization method, the blending amount of the phosphate 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 with respect to 100 parts by mass of slaked lime (in terms of CaO). By setting it within such a range, the content of phosphorus atoms in the resulting calcium-based carbonate compound can be set within a predetermined range.

[0040] Although the method for setting the content of sulfur atoms in the calcium-based carbonate compound within the above range is not particularly limited, for example, in order to control so that the aspect ratio does not become too large (for example, does not exceed 20), a sulfuric acid compound may be added. However, methods such as reducing the addition amount of the sulfuric acid compound or not adding the sulfuric acid compound in order to control to a predetermined aspect ratio, or a method of dissolving and removing the sulfuric acid compound in the raw material of slaked lime with a strong alkali can be mentioned.

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

[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 a slurry or cake form without undergoing filtration and drying.

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

[0044] <Uses of Calcium-based Carbonate Compounds> The uses of calcium-based carbonate compounds are not particularly limited. As uses, for example, they are suitable as high-functional materials for inorganic molded bodies typified by building materials, fillers for resins, and the like. Hereinafter, the mode of using calcium-based carbonate compounds in inorganic molded bodies will be described.

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

[0046] (Hydraulic Material) Examples of the hydraulic material include cementitious materials, gypsum, lime, slag, etc. 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, etc. Examples of the 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 the materials constituting the inorganic molded body. By setting the content of the hydraulic material within the above range, the physical properties such as the flexural strength and peel strength of the inorganic molded body can be improved, and the increase in the bulk specific gravity of the inorganic molded body can be suppressed, thereby enhancing the workability during construction and the like.

[0048] (Siliceous material) Examples of the siliceous material include silica sand, silica powder, silica fume, fly ash, diatomaceous earth, layered silicates (e.g., mica, talc, kaolin, bentonite) , WA Wollastonite, lightweight aggregates (e.g., fly ash balloons, perlite, shirasu balloons, glass foams, etc.), and other materials containing a large amount of SiO2. 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 inorganic molded body. 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 inorganic molded body within the target range. Note that as the siliceous material, the unit volume mass of perlite, fly ash balloons, shirasu balloons, etc. is 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 inorganic molded body.

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

[0051] In order to improve the strength and impart toughness to 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 the materials constituting the inorganic molded body. 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 inorganic molded body and improve the smoothness. When an inorganic reinforcing fiber material having an average length of 1 mm to 50 mm is blended as the reinforcing fiber material, in order to improve the smoothness of the inorganic molded body, 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 inorganic molded body.

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

[0054] (Optional component) In addition to the above materials, in order to impart various functions to the inorganic molded body, resin hollow bodies, wood chips, wood powder, resin powder, defoaming agents, flocculants, water repellents, thickeners (such as methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, etc.), dispersants and other materials can be variously blended according to the purpose. Also, it is possible to appropriately add and use recycled materials obtained by pulverizing waste materials generated during the processing of the inorganic molded body.

[0055] The bulk density of the inorganic molded body is preferably 0.7 g / mL or more and 1.4 g / cm 3 or less, more preferably 0.8 g / mL or more and 1.2 g / cm 3 or less, and even more preferably 0.9 g / mL or more and 1.1 g / cm 3 or less.

[0056] (Method for manufacturing an inorganic molded body) The method for manufacturing the inorganic molded body according to this embodiment is not particularly limited, and generally used papermaking methods, extrusion molding methods, flow-on molding methods, casting molding methods, press (compression) molding, etc. can be used. The inorganic molded body can be obtained by subjecting the green sheet molded by these methods to press dehydration or pattern processing such as embossing, and then curing at room temperature, steam curing, autoclave curing, etc. Further, drying may be performed, and shape processing or painting may be performed as necessary.

[0057] (Uses of the inorganic molded body) The uses of the inorganic molded body are not particularly limited, and it can be suitably used as performance maintenance materials such as building wall materials, floor materials, roof materials, various boards, exterior decoration members, interior and exterior finishing materials such as furniture, sealing materials, heat insulating materials, sound absorbing materials, waterproof materials, 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, 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 obtained by mixing concentrated hydrochloric acid and water at a volume ratio of 1:1) with a pipette, and heated and dissolved it. After cooling, it was transferred to a 250 mL volumetric flask, and water was added to make up to 250 mL. From this, 20 mL was aliquoted into a 50 mL volumetric flask, and water was added to make up to 50 mL to obtain a test solution for measurement. On the other hand, 20 mL was aliquoted from the above-mentioned 250 mL made-up aqueous solution into 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 Integration times: 3 times Sample order: For each sample Measurement method: Standard addition method Calibration curve weighting: None Measurement wavelengths: 177.495 nm for phosphorus atom, 182.034 nm for sulfur atom, 251.612 nm for silicon atom

[0062] (2) Content C of sulfur atom S (ppm) Content C of phosphorus atom P (ppm) Ratio (C S / C P ) Content C of sulfur atom obtained in (1) above S (ppm) and content C of phosphorus atom P (ppm) to calculate the ratio (C S / C P ).

[0063] (3) BET specific surface area Using an 8 - unit pre - heating unit (manufactured by MOUNTECH), the sample powder pre - treated at about 130 °C for about 30 minutes in a nitrogen gas atmosphere 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.

[0064] (4) Average particle size by laser diffraction method 50 mL of ethanol was taken in a 100 - mL beaker, and about 0.2 g of sample powder was put into the above - mentioned 100 - mL beaker. After ultrasonic treatment (UD - 201 manufactured by Tomy Seiko Co., Ltd.) for 3 minutes, a dispersion was prepared. This dispersion was measured for the volume - based D 50 value as the average particle size (μm) using a laser diffraction method - particle size distribution meter (Microtrac HRA Model 9320 - X100 manufactured by Nikkiso Co., Ltd.).

[0065] (5) Calculation of average major axis, average minor axis and aspect ratio by scanning electron microscope observation A double-sided tape was attached to the aluminum sample stage, and the sample powder was applied onto it as if tracing with the 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 5. Regarding the obtained SEM photographs, using image analysis software (Image J), 20 particles in the photograph were randomly selected, and the average values of the major axis, minor axis (the distance across when taking an axis perpendicular to the major axis 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 obtained respectively.

[0066] <Production of calcium-based carbonate compound> [Example 1-1] Calcium-based carbonate compound (aspect ratio 6.6) 7000 g of quicklime powder produced by co-firing limestone and coal was put into 50 L of water at 70 °C with stirring and slaked for 1 hour to prepare lime milk. 6980 g in terms of CaO of this lime milk, 630 g of aragonite seed crystal powder, and 500 g of disodium hydrogen phosphate dodecahydrate were prepared, and each was put into a 220 L capacity SUS container with baffles pre-filled with 180 L of water with stirring to prepare a mixed slurry of raw materials. Then, the temperature was raised to 70 °C, and at this temperature, it was stirred at a rotational speed of 150 rpm using a stirrer equipped with a single-stage turbine blade. An exhaust gas extraction pipe was connected to the exhaust outlet of a steam production boiler using LNG as fuel, and while drawing in the exhaust gas using a test blower, when measured with a CO2 concentration measuring instrument (XP-3140 manufactured by Shin 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 speed 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 relative to the solid content, dried at 110 °C for 24 hours, pulverized, and a sample powder of the calcium-based carbonate compound was obtained.

[0067] [Example 1-2] Calcium-based carbonate compound (aspect ratio 8.6) A commercially available slaked lime powder (manufactured by Yoshimi Lime Industry Co., Ltd., the best industrial slaked lime) was 6980 g in terms of CaO, 630 g of aragonite seed crystal powder, and 1500 g of disodium hydrogen phosphate dodecahydrate were added, and the same operations as in Example 1-1 were carried out to obtain a sample powder of a calcium-based carbonate compound.

[0068] [Example 1-3] Calcium-based carbonate compound (aspect ratio 10.4) A commercially available slaked lime powder (manufactured by Yoshimi Lime Industry Co., Ltd., the best industrial slaked lime) was 6980 g in terms of CaO, 630 g of aragonite seed crystal powder, and 500 g of disodium hydrogen phosphate dodecahydrate were added, and the same operations as in Example 1-1 were carried out to obtain a sample powder of a calcium-based carbonate compound.

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

[0070] [Comparative Example 1-1] Calcium-based carbonate compound (aspect ratio 5.2) A commercially available slaked lime powder (manufactured by Yoshimi Lime Industry Co., Ltd., the best industrial slaked lime) was 6980 g in terms of 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, and the same operations as in Example 1-1 were carried out to obtain a sample powder of a calcium-based carbonate compound.

[0071] [Comparative Example 1-2] Calcium-based carbonate compound (aspect ratio 5.3) 6,980 g of commercially available slaked lime powder (manufactured by Yoshimi Lime Industry Co., Ltd., the best industrial slaked lime), 630 g of aragonite seed crystal powder, and 3,000 g of disodium hydrogen phosphate dodecahydrate were added, and the same operations as in Example 1-1 were performed to obtain a sample powder of a calcium-based carbonate compound.

[0072]

Table 1

[0073] <Manufacture of Inorganic Shaped Bodies> Inorganic shaped bodies were manufactured by a papermaking method and an extrusion molding method according to the following procedure. The blending amounts of the components used are all shown in "parts by mass" unless otherwise specified. In the following table, "-" indicates that the corresponding component was not used.

[0074] [Example 2-1] Manufacture of Inorganic Shaped Body by Papermaking Method The materials shown in Table 2 below were put into a plastic container and stirred and mixed to obtain a raw material slurry. The calcium-based carbonate compound of Example 1-1 was used as the calcium-based carbonate compound. The raw material slurry was divided and put into a filter covered with felt, and a laminated plate (long side 28 mm × short side 24 mm × thickness 14 mm) was produced while performing suction filtration with a vacuum pump. The laminated plate was taken out of the filter and subjected to a dehydration press. The thickness after pressing was 13 mm. After autoclave curing (curing pressure (gauge pressure) 9 kgf; curing time 12 hr), the pressed body was dried in a dryer (105°C) for 24 hr. Both sides were polished with a sander to adjust the thickness to 12 mm, and an inorganic shaped body was obtained.

[0075] [Example 2-2] Manufacture of Inorganic Shaped Body by Papermaking Method An inorganic shaped body was obtained in the same manner as in Example 2-1, except that the calcium-based carbonate compound of Example 1-2 was used as the calcium-based carbonate compound.

[0076] [Example 2-3] Manufacture of Inorganic Shaped Body by Papermaking Method An inorganic molded body was obtained in the same manner as in Example 2-1, except that the calcium-based carbonate compounds of Examples 1-3 were used as the calcium-based carbonate compound.

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

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

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

[0080] [Comparative Example 2-3] Production of an inorganic molded body by a papermaking method An inorganic molded body was obtained in the same manner as in Example 2-1, except that a calcium-based carbonate compound having an aspect ratio of 25 was used as the calcium-based carbonate compound. However, since the calcium-based carbonate compound broke during molding and the original shape could not be maintained, evaluation was not performed.

[0081] [Evaluation of inorganic molded body] The following evaluations were performed on the inorganic molded bodies produced by the papermaking method in the examples and comparative examples. 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 conducted with the following apparatus and procedure. Figure 6 is a partially perspective view schematically showing a heating tester. As shown in Figure 6, between the test specimen and the heat source, a refractory material was assembled so that it could be stabilized at around 900 °C using an electric heater as the heat source, and the temperature of the back surface of the test specimen could be measured with a thermocouple. Specifically, as the heat source equipment, an electric heater (1.2 kW heater) was fixed on the heating surface side of the test specimen so that the distance from the heat source was about 70 mm.

[0084] The test procedure was as follows. (1) A discard plate was installed, and after preheating to 902 °C, the heating was once stopped. (2) After the heating surface side reached 200 °C or lower, it was replaced with the test specimen. (3) A thermocouple was placed at the center of the back surface (the upper surface in the figure) of the test specimen, and a calcium silicate plate (about 30 mm × 70 mm) and a weight were placed and fixed. (4) Heating was started and left for a predetermined time (45 minutes), and the temperatures on the front surface side and the back surface side were recorded with a data logger. During this period, the temperature setting of the electric heater was 902 °C on the heating surface side, and it was controlled with a thermostat with 900 °C as the lower limit. Also, the temperature measurement interval of the data logger was set to every 10 seconds, and data was recorded at this interval. (5) After the test was completed, the test specimen was taken out, and the following items were measured (each item was also measured before the test). · Dimensions: The vertical and horizontal lengths of the back surface and the heating surface were measured with a caliper. The area (mm 2 ) of the heating surface before and after the test was calculated, and the heating surface shrinkage (%) was obtained based on the following formula. Heating surface shrinkage (%) = {|S1 - S0| / S0} × 100 (In the formula, S0 is the area of the heating surface before the test, and S1 is the area of the heating surface after the test.)

[0085]

Table 2

[0086] In the inorganic molded body of the example, both the heating surface shrinkage and the back surface temperature rise were superior to those of the comparative example and showed good fire resistance. Further, in the inorganic molded body of the example, no cracks occurred 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-stirred for 3 minutes. The calcium-based carbonate compound of Example 1-1 was used as the calcium-based carbonate compound. Next, water was added and wet-stirred for 2 minutes. The raw materials after wet-stirring were kneaded with an Ishikawa-type extruder and then extrusion-molded with an Ishikawa-type extruder. Thereby, a molded body having a long side of 600 mm × a short side of 190 mm × a thickness of 13 mm) was produced. After obtaining the molded body, it was put into a thermo-hygrostat set at 60 ° C. / 98% for primary curing, and further pressurized to 9 kgf for autoclave curing for 12 hours. By polishing both sides of the molded body with a sander to a thickness of 12 mm, an inorganic molded body was produced.

[0088] [Example 3-2] Production of Inorganic Molded Body by Extrusion Molding Method An inorganic molded body was obtained in the same manner as in Example 3-1, except that the calcium-based carbonate compound of Example 1-2 was used as the calcium-based carbonate compound.

[0089] [Example 3-3] Production of Inorganic Molded Body by Extrusion Molding Method An inorganic molded body was obtained in the same manner as in Example 3-1, except that the calcium-based carbonate compound of Example 1-3 was used as the calcium-based carbonate compound.

[0090] [Example 3-4] Production of Inorganic Molded Body by Extrusion Molding Method An inorganic molded body was obtained in the same manner as in Example 3-1, except that the calcium-based carbonate compound of Example 1-4 was used as the calcium-based carbonate compound.

[0091] [Comparative Example 3-1] Production of Inorganic Molded Body by Extrusion Molding Method An inorganic molded 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 molded 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 molded body was obtained in the same manner as in Example 3-1, except that the calcium carbonate compound having an aspect ratio of 25 was used as the calcium carbonate compound. However, since the calcium carbonate compound broke during molding and the original shape could not be maintained, evaluation was not performed.

[0094] [Evaluation of Inorganic Molded Body] The following evaluations were performed on the inorganic molded bodies produced by the extrusion molding method in the production examples and comparative production examples. The results are shown in Table 3.

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

[0096] (Three-Point Bending Test) The three-point bending test was measured in accordance with JIS A 5430. The result was taken as the strength (N / mm 2 ) of the inorganic cement-based molded body plate.

[0097] (Heating Test) In addition to being measured in the same manner as in the case of the papermaking method, after the test in (5), the test piece was taken out and the following items were measured (each item was also measured before the test). · Warping: The test piece was placed on an iron surface plate, and the height from the iron surface plate at the center of each side of the test piece was measured with a thickness gauge, and the average value (mm) was taken. This average value was taken as the warping after heating (mm).

[0098]

Table 3

[0099] In the inorganic molded body of the example, any of the strength, the shrinkage of the heating surface , increase in the inner surface temperature and the warpage after heating was equal to or better than that of the comparative example, showing good strength and fire resistance. Further, in the inorganic molded body of the example, no cracks occurred after heating (not shown).

Claims

1. The calcium-based carbonate compound has a phosphorus atom content of 1000 ppm or more and 15000 ppm or less, a sulfur atom content of 2000 ppm or less, an aspect ratio of the average major axis to the average minor axis of 6 or more and 19 or less, and is a calcium-based carbonate compound.

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

3. The calcium-based carbonate compound according to Claim 2, having a total content of phosphorus atoms, silicon atoms, and sulfur atoms of 1000 ppm or more and 18000 ppm or less.

4. The ratio (C Ｓ / C Ｐ ) of the content C Ｓ (ppm) of the sulfur atoms to the content C Ｐ (ppm) of the phosphorus atoms is 0.30 or less. The calcium-based carbonate compound according to Claim 1.

5. The calcium-based carbonate compound according to Claim 1, having an average particle diameter by the laser diffraction method of 1.1 μm or more and 12.5 μm or less.

6. The calcium-based carbonate compound according to Claim 1, having an average major axis by observation with a scanning electron microscope of 0.5 μm or more and 25 μm or less.

7. The calcium-based carbonate compound according to Claim 1, having a BET specific surface area of 1 m ２ / g or more and 10 m ２ / g or less.

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

9. The calcium-based carbonate compound according to any one of Claims 1 to 8, which is for an inorganic molded body.

10. An inorganic molded body containing a calcium-based carbonate compound according to any one of claims 1 to 8.

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