Calcium carbonate compounds and inorganic shaped bodies

Abstract

This invention provides a calcium-based carbonate compound and an inorganic molded article. When used in an inorganic molded article as a building material, the calcium-based carbonate compound maintains the flowability of the mixture during manufacturing and simultaneously improves the strength of the inorganic molded article. The calcium-based carbonate compound of this invention is cubic in shape and is used in inorganic molded articles. The average particle size of the calcium-based carbonate compound obtained by laser diffraction is preferably 2 μm to 25 μm. The BET specific surface area of ​​the calcium-based carbonate compound is preferably 0.3 m². 2 / g or more 3 m 2 / g or less.

Description

Technical Field

[0001] This invention relates to a calcium carbonate compound and an inorganic molded body. Background Technology

[0002] Inorganic molded bodies are mostly composed of inorganic substances such as hydraulic materials or silicate materials. Due to their fire resistance, lightweight, high strength, and workability, they are widely used in exterior wall materials, roofing substrates, and eaves materials for residential buildings. In addition, they are also widely used in the foundations, walls, columns, and floors of buildings requiring strength or fire resistance.

[0003] As a technique for improving the strength, one of the important properties required for inorganic molded bodies, a technique of incorporating needle-shaped calcium carbonate has been proposed (Japanese Patent No. 6898926).

[0004] [Previous Technical Documents] [Patent Literature] [Patent Document 1]: Japanese Patent No. 6898926. Summary of the Invention

[0005] [The problem that the invention aims to solve] However, even with the above-mentioned techniques, there are concerns that the strength of the obtained inorganic molded articles may decrease, the fluidity of the raw material mixture may decrease during the manufacturing process, and even the overall efficiency of the manufacturing process may decrease.

[0006] The purpose of this invention is to provide a calcium carbonate compound and an inorganic molded body, wherein when the calcium carbonate compound is used as an inorganic molded body as a building material, it can maintain the fluidity of the mixture during the manufacturing process and at the same time improve the strength of the inorganic molded body.

[0007] [Technical means to solve the problem] The inventors have conducted repeated and dedicated research and have found that the above-mentioned problems can be solved by the following structure, thereby completing the present invention.

[0008] In one implementation scheme This invention relates to a calcium carbonate compound, which is cubic in shape and used in inorganic molded articles.

[0009] In the field of inorganic molded articles, it is well known that needle-like or fibrous reinforcing materials, such as acicular calcium carbonate, are used to improve the strength of inorganic molded articles. However, if the amount of acicular reinforcing material is increased to further improve strength, the fluidity of the mixture will decrease as mentioned above. Therefore, there is a trade-off between increasing strength and maintaining fluidity. The inventors conducted repeated research and unexpectedly discovered that cubic calcium carbonate compounds can maintain the fluidity of the mixture during the manufacturing process while simultaneously improving the strength of the obtained inorganic molded article. The present invention is an extension of this novel insight. In summary, this calcium carbonate compound is suitable for use as an inorganic molded article.

[0010] While the exact reason why this calcium carbonate compound achieves both fluidity and strength is uncertain, it is speculated as follows: Because the calcium carbonate compound is cubic, the shear stress in the mixture decreases, and the viscosity-increasing effect is less compared to needle-like substances. As a result, the fluidity of the mixture can be maintained. Furthermore, the strength of the inorganic molded article can be improved through the increased strength or density of the calcium carbonate compound itself due to its cubic shape, and through homogeneous dispersion or homogeneous filling caused by the isotropic (non-directional) properties of the mixture. Moreover, mixtures containing needle-like substances have higher viscosity, making it difficult for air bubbles to escape. If a final product is obtained while retaining residual air bubbles, there is a concern about a decrease in the strength of the final product. However, with a cubic calcium carbonate compound, the air bubbles in the mixture easily escape due to the fluidity or isotropic properties described above; therefore, it is speculated that this can prevent a decrease in strength or even increase strength.

[0011] In this specification, "cubic" refers to a shape that can be roughly considered as a cube, and is not limited to a standard cube shape. For example, a cube is considered cubic if "one or more vertices of the cube are curved or have gaps, but the cube can be restored by filling in these gaps." Furthermore, a target shape is considered cubic if the length of one side of the target shape is between 50% and 150% of the length of the other side. Moreover, the shape of one face of the target shape is not limited to a square; it can be any shape such as a trapezoid, rhombus, or quadrilateral with four different side lengths, as long as the aforementioned ratio of the two sides is satisfied. In addition, it is not necessary for all particles constituting the calcium carbonate compound to be cubic; the calcium carbonate compound is cubic when the proportion of cubic particles among all particles is maximized.

[0012] In this specification, "calcium carbonate compound" refers to a compound with calcium carbonate as its main component, and it is permissible to contain or coexist with other byproducts that may be introduced during manufacturing processes. The calcium carbonate content in the calcium carbonate compound is preferably 80% by mass or more. The determination of the calcium carbonate content in the calcium carbonate compound can be suitably achieved using the disodium ethylenediaminetetraacetate titration method.

[0013] <Disodium ethylenediaminetetraacetate titration method> Weigh 1 g of the calcium carbonate compound (dried at 105°C for 2 hours) as the sample, suspend it in 50 mL of water, add 10 mL of hydrochloric acid (a solution prepared by mixing concentrated hydrochloric acid and water in a 1:1 volume ratio), and heat to dissolve. After cooling, transfer it to a 250 mL volumetric flask, and add water to bring the volume to 250 mL. Take 5.00 mL of this solution and add water to make the total volume of the solution approximately 50 mL. Add 5 mL of buffer solution (a 1,000 mL solution prepared by dissolving 500 g of potassium hydroxide in water), and then add commercially available Dotite NN dilution powder. Titrate using a titrant (a 1,000 mL solution prepared by dissolving approximately 3.8 g of disodium ethylenediaminetetraacetate in water). Stop titrating when the color of the liquid changes from red to blue. Calculate the calcium carbonate content (%) according to the following formula. (In the formula, f is the titrant factor. The factor is determined by titrating the reagent and standardizing it using BT indicator. V is the volume of titrant consumed (mL). W is the sample volume (0.02 g of calcium carbonate).) In one embodiment, the average particle size of the calcium carbonate compound obtained by laser diffraction is preferably 2 μm or more and 25 μm or less. In one embodiment, the BET specific surface area of ​​the calcium carbonate compound is preferably 0.3 m². 2 / g or more 3 m 2 / g or less. Furthermore, in one embodiment, the apparent specific gravity of the aforementioned calcium carbonate compound is preferably 1 g / mL or more and 2 g / mL or less. By satisfying a single one of these properties, or a combination of these properties, a higher level of both fluidity and strength can be achieved.

[0014] In one embodiment, based on the aforementioned calcium carbonate compound, the flow time of the P funnel can be set to between 7 and 10 seconds. Therefore, the aforementioned calcium carbonate compound exhibits good flowability.

[0015] In one embodiment, the magnesium content in the aforementioned calcium carbonate compound can be 1000 ppm or more. The magnesium content in the calcium carbonate compound can vary depending on the raw materials or manufacturing method. For example, if a relatively magnesium-rich raw material (such as seawater) is used, the magnesium content in the calcium carbonate compound will be 1000 ppm or more. If a relatively magnesium-poor raw material (such as supernatant from concrete sludge) is used, the magnesium content in the calcium carbonate compound will be less than 1000 ppm.

[0016] In one embodiment, the calcium carbonate compound is preferably a synthetic calcium carbonate compound in terms of production efficiency or shape control.

[0017] In other implementation schemes, This invention relates to an inorganic molded body containing the calcium carbonate compound.

[0018] By applying cubic calcium carbonate compounds to inorganic molded parts, it is possible to maintain flowability and good workability during the manufacturing process, while simultaneously obtaining inorganic molded parts with high strength efficiently. Attached Figure Description

[0019] [ Figure 1 [Image 1] is a SEM image of the calcium carbonate compound of Example 1-1 of the present invention.

[0020] [ Figure 2 [Image 1] is a SEM image of the calcium carbonate compound of Comparative Example 1-1 of the present invention. Detailed Implementation

[0021] The following describes a calcium-based carbonate compound and an inorganic molded article according to one embodiment of the present invention. The present invention is not limited to these embodiments.

[0022] <Calcium carbonate compounds> The calcium carbonate compound in this embodiment is cubic in shape and is suitable for use as an inorganic molded body.

[0023] The average particle size obtained by laser diffraction of the aforementioned calcium carbonate compound is preferably 2 μm or more and 25 μm or less, more preferably 4 μm or more and 22 μm or less, and even more preferably 6 μm or more and 18 μm or less. This allows for suitable maintenance of the flowability of the mixture containing the calcium carbonate compound. Furthermore, it improves the strength of the obtained inorganic molded article.

[0024] The preferred BET specific surface area of ​​the above-mentioned calcium carbonate compound is 0.3 m². 2 / g or more 3 m 2 / g or less, more preferably 0.4 m 2 / g or more 2.6 m 2 / g or less, and more preferably 0.5 m 2 / g or more 2.4 m 2 / g or less. This allows for the suitable maintenance of the flowability of mixtures containing calcium carbonate compounds, and also improves the dispersibility of the calcium carbonate compounds. Furthermore, it further enhances the strength of the obtained inorganic molded articles.

[0025] The apparent specific gravity of the aforementioned calcium carbonate compound is preferably 1.00 g / mL or more and 2.00 g / mL or less, more preferably 1.05 g / mL or more and 1.80 g / mL or less, and even more preferably 1.10 g / mL or more and 1.60 g / mL or less. This allows for suitable maintenance of the flowability of the mixture containing the calcium carbonate compound. Furthermore, a higher density or strength of the calcium carbonate compound further improves the strength of the obtained inorganic molded article.

[0026] The preferred flow time of the aforementioned calcium carbonate compound through the P-funnel is 7 seconds to 10 seconds, more preferably 7.5 seconds to 9.8 seconds, and even more preferably 8 seconds to 9.5 seconds. Since this calcium carbonate compound is cubic in shape, it exhibits excellent flowability.

[0027] The magnesium content in the aforementioned calcium carbonate compounds can be above 1000 ppm, above 5000 ppm, or even above 10000 ppm. Although the upper limit of magnesium content varies depending on the raw materials or manufacturing methods, it is around 50000 ppm.

[0028] As for the crystal structure of calcium carbonate compounds, calcite type, aragonite type, or a combination thereof can be suitably adopted. In terms of obtaining cubic calcium carbonate compounds, calcite type crystal structure is preferred, while aragonite type crystal structure is relatively less common.

[0029] In the X-ray diffraction measurements of the above-mentioned calcium carbonate compounds, the peak intensity I of aragonite was... a relative to the peak intensity I of calcite c The ratio of I a / I c Preferably, the concentration is 0.1 or less, more preferably 0.08 or less, and even more preferably 0.06 or less. This allows for the efficient production of cubic calcium carbonate compounds.

[0030] In terms of production efficiency or shape control, the aforementioned calcium carbonate compounds are preferably synthetic calcium carbonate compounds.

[0031] (Method for manufacturing calcium carbonate compounds) There are no particular limitations on the method for manufacturing calcium carbonate compounds, and well-known manufacturing methods can be used. As a representative example, a solution method that "manufactures calcium carbonate compounds by contacting carbonates (carbonate ions) with calcium (calcium ions) in seawater, etc., to perform salt exchange" can be appropriately used.

[0032] Ca 2+ +CO3 2- →CaCO3(A) As the salt for the carbonate ion used in reaction (A), alkali metal salts (Li, Na, K) and alkaline earth metal salts (Mg, Sr, but without Ca) can be used, with alkali metal salts being suitable. Among these, Na salts (sodium carbonate) are preferred in terms of versatility and cost.

[0033] Regarding the contact between carbonates and seawater, the reaction can be carried out by adding an aqueous solution or slurry of the carbonate to the seawater, or vice versa. In terms of efficiently obtaining the desired cubic calcium carbonate compound, a one-time addition is preferred.

[0034] Regarding seawater, it can be used directly from nearby sea areas, or after filtration or other treatments. The source is not limited to nearshore areas; it can be obtained from any location where seawater is available. Seawater rich in calcium, produced during the removal of magnesium hydroxide from seawater, can also be used.

[0035] Regarding the amount of carbonate added, there are no particular limitations as long as it is set according to the above reaction formula (A) in a way that obtains the amount of carbonate ions required to react with the amount of calcium ions in seawater, etc. The amounts of calcium ions and carbonate ions are preferably equal in moles, but they can also be in the range of ±50 to 200% in mole ratio of carbonate ions to calcium ions.

[0036] The salt exchange reaction that occurs when carbonates come into contact with seawater, etc., proceeds relatively quickly. The reaction time can be set to allow the salt exchange reaction to proceed sufficiently; it can be set to 1 second or more, preferably 1 minute or more but less than 60 minutes, and more preferably 5 minutes or more but less than 50 minutes.

[0037] The generated calcium carbonate compounds can be filtered and extracted, then dried to form a powder. Alternatively, they can be kept in slurry or filter cake form without filtration and drying and used as a source of calcium carbonate compounds.

[0038] <Inorganic Molded Body> There are no particular limitations on inorganic molded materials; for example, molded panels for building materials or concrete structures (concrete molded bodies) can be cited. Below, we will describe in detail the applicable compositions according to their uses.

[0039] (Formed panels for building materials) The forming plate preferably comprises hydraulic materials, silicate materials, reinforcing fiber materials, and calcium carbonate compounds.

[0040] (Hydraulic materials) Examples of hydraulic materials include: cementitious materials, gypsum, lime, and slag. Examples of cementitious materials include commonly used cement, such as: ordinary Portland cement, early-strength cement, intermediate-heat cement, fly ash cement, blast furnace slag cement, and alumina cement. Examples of gypsum include: anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum. Examples of slag include: blast furnace slag and converter slag. These hydraulic materials can be used individually or in combination of two or more.

[0041] The content of hydraulic material is based on the total amount of material constituting the molded sheet, preferably 5% to 45% by mass, more preferably 8% to 42% by mass, and even more preferably 10% to 40% by mass. By setting the content of hydraulic material within the above range, it is possible to improve the physical properties of the molded sheet, such as flexural strength or peel strength, and to suppress the increase of the bulk density of the molded sheet, thereby improving workability during construction.

[0042] (Silicic materials) Examples of silicate materials include silica sand, silica powder, silica ash, fly ash, diatomaceous earth, layered silicates (e.g., mica, talc, kaolin, bentonite), wollastonite, and lightweight scaffold materials (e.g., fly ash hollow spheres, perlite, volcanic ash hollow spheres, glass foam, etc.) that contain a significant amount of SiO2. These silicate materials can be used individually or in combination of two or more. Talc, mica, or wollastonite can also be used as reinforcing fiber materials as described below.

[0043] The content of silicate material is based on the total amount of material constituting the molded plate, preferably 10% to 55% by mass, more preferably 12% to 50% by mass, and even more preferably 15% to 45% by mass. If the content of silicate material is within the above range, it becomes possible to set the flexural strength, bulk density, water absorption rate, dimensional stability, etc., of the molded plate as target ranges. Furthermore, the content of silicate material is such that the bulk density is 0.5 g / cm³ when mixed with perlite, fly ash hollow spheres, volcanic ash hollow spheres, etc. 3When the following lightweight skeleton material is a silicate material, in order to prevent the bulk density from becoming too light and the strength such as flexural strength or peel strength from weakening, it is preferable to use other silicate materials to make the content of the lightweight skeleton material less than 20% by mass based on the total amount of material constituting the molded plate.

[0044] (Reinforcing fiber material) As reinforcing fiber materials, for example, the following can be used: softwood pulp, hardwood pulp, pulp obtained by fibrillating these materials, pulp obtained by defibrating waste paper, etc.; 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.

[0045] To improve the strength and toughness of the formed plate, the content of the reinforcing fiber material is preferably 2% to 30% by mass, more preferably 3% to 26% by mass, and even more preferably 4% to 22% by mass, based on the total amount of material constituting the formed plate. By setting the content of the reinforcing fiber material within the above range, sufficient reinforcing effect can be achieved, while simultaneously suppressing fiber protrusion onto the surface of the formed plate and improving smoothness. When using inorganic reinforcing fiber material with an average length of 1 mm to 50 mm as the reinforcing fiber material, in order to improve the smoothness of the formed plate, it is preferable to use other reinforcing fiber materials so that their content is reduced to 10% by mass or less based on the total amount of material constituting the formed plate.

[0046] (Calcium carbonate compounds) The above-mentioned calcium carbonate compounds can be used as calcium carbonate compounds.

[0047] The content of calcium carbonate compounds is based on the total amount of materials constituting the molded plate, preferably 5% to 60% by mass, more preferably 8% to 55% by mass, and even more preferably 12% to 50% by mass. By incorporating calcium carbonate compounds with low thermal conductivity at the above-mentioned ranges, the strength or fire resistance of the molded plate can be improved.

[0048] (Any ingredient) In addition to the materials mentioned above, various materials may be incorporated into the molded board to impart various functions: resin hollow materials, wood chips, wood flour, resin powder, defoamers, coagulants, water repellents, tackifiers (methylcellulose, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, etc.), dispersants, etc. Furthermore, recycled materials obtained by crushing scraps and offcuts generated during the processing of the molded board may also be added appropriately.

[0049] The bulk density of the above-mentioned formed plate is preferably 0.7 g / cm³. 3Above 2.0 g / cm 3 The following is more preferably 0.8 g / cm³. 3 The above 1.8 g / cm 3 The preferred value is 0.9 g / cm³. 3 Above 1.6 g / cm 3 the following.

[0050] (Manufacturing method of the formed plate) The manufacturing method of the formed sheet in this embodiment is not particularly limited, and commonly used methods such as paper forming, extrusion forming, flow forming, casting forming, and pressure (compression) forming can be used. The formed sheet can be obtained by subjecting the blank sheet formed by these methods to pressure dehydration or embossing, followed by curing by room temperature curing, steam curing, autoclave curing, etc. Furthermore, it can be dried, and shaped or coated as needed.

[0051] (Applications of formed plates) The applications of the molded board are not particularly limited, and it can be suitable as a building wall material, flooring material, roofing material, various panels, exterior decorative components, accessories, and other interior and exterior finishing materials, sealing materials, heat insulation materials, sound absorbing materials, waterproofing materials, and other performance-maintaining materials. The molded board is preferably a cement-based molded board containing cementitious materials, and more preferably a calcium silicate molded body.

[0052] (Concrete building) Concrete structures are hardened bodies composed of hydraulic components. These hydraulic components consist of powders containing, in addition to calcium carbonate compounds, at least one of the following: blast furnace slag, expanding materials, hydrated lime, quicklime, fly ash, and Portland cement. The aforementioned calcium carbonate compounds may be suitable.

[0053] In addition to the aforementioned hydraulic components, hydraulic component mixtures can also be manufactured by mixing in skeleton materials such as sand or gravel, agents such as concrete chemical admixtures, metals, or fiber materials formed from polymer materials.

[0054] The hardened form of a hydraulic component is obtained by mixing water into the aforementioned hydraulic component to obtain a paste, and then hardening the paste. Furthermore, the hardened form of a hydraulic component mixture is obtained by mixing water into the aforementioned hydraulic component mixture to obtain a mixture (equivalent to freshly mixed mortar or freshly mixed concrete), and then hardening the mixture; it is equivalent to mortar or concrete.

[0055] The ratio of the calcium-based carbonate compound in the above powder (the ratio of the calcium-based carbonate compound to cement) is within the range of 1% to 60% by mass, preferably within the range of 3% to 50% by mass, and more preferably within the range of 5% to 40% by mass.

[0056] It is preferable to use blast furnace slag powder used in JIS (Japanese Industrial Standards) R5211 "Blast Furnace Cement" or blast furnace slag powder conforming to JIS A6206 "Blast Furnace Slag for Concrete" as the blast furnace slag. In addition, it is preferable to use blast furnace slag with a specific surface area of 2000 to 10000 cm 2 / g, preferably 3500 to 7000 cm 2 / g.

[0057] As the expansion material, it is sufficient to use, for example, the expansion material specified in JIS A6202 "Expansion Material for Concrete". It is preferable to add the expansion material at a ratio of 2 to 9% by mass based on the entire hydraulic composition.

[0058] As the slaked lime, it is sufficient to use, for example, the one specified in JIS R9001 "Lime for Industrial Use". Also, since quicklime becomes slaked lime when it comes into contact with water, for example, quicklime specified in JIS R9001 "Lime for Industrial Use" can be used instead of slaked lime. Furthermore, in this case, the amount of water required for quicklime to become slaked lime can be supplemented in advance.

[0059] As the fly ash, it is sufficient to use, for example, the one conforming to JIS A6201 "Fly Ash for Concrete".

[0060] Ordinary Portland cement is used as the Portland cement. In addition, as the Portland cement, those specified in JIS R5210 "Portland Cement" such as early strength Portland cement, super early strength Portland cement, medium heat Portland cement, low heat Portland cement, sulfate resistant Portland cement, etc., and JIS R5214 "Environmentally Friendly Cement" can also be used.

[0061] When the hydraulic composition contains Portland cement, the ratio of Portland cement in the powder other than the calcium-based carbonate compound is set to 70% by mass or less, preferably set to 30% by mass or less.

[0062] In addition, when using Portland cement and blast furnace slag or fly ash, for example, JIS R5211 "Blast Furnace Cement" or, for example, JIS R5213 "Fly Ash Cement" pre-mixed with these components can be used separately, or these cements can also be mixed and used.

[0063] Due to the use of calcium-based carbonate compounds with the above characteristics, the hydraulic components or hydraulic component mixtures exhibit good fluidity, and their hardened concrete exhibits excellent compressive strength.

[0064] The density of the aforementioned concrete structure is preferably 0.7 g / cm³. 3 Above 2.0 g / cm 3 The following is more preferably 0.8 g / cm³. 3 The above 1.8 g / cm 3 The preferred value is 0.9 g / cm³. 3 Above 1.6 g / cm 3 the following.

[0065] [Example] The present invention will now be described in detail using examples, but the invention is not limited to the following examples without departing from its spirit. Furthermore, the measurement and evaluation of physical properties, etc., are performed as follows.

[0066] <Evaluation of Calcium Carbonate Compounds> The calcium carbonate compounds obtained in each manufacturing example were analyzed as follows. The analytical results are shown in Table 1 and... Figure 1 , Figure 2 middle.

[0067] (1) BET specific surface area Using an eight-unit preheating unit (manufactured by MOUNTECH), sample powder pretreated at approximately 130°C for about 30 minutes under nitrogen atmosphere was analyzed. A Macsorb HM Model-1208 (manufactured by MOUNTECH) was used as the BET surface area measuring device, and the BET surface area (m²) was determined using nitrogen adsorption. 2 / g).

[0068] (2) Average particle size obtained by laser diffraction 50 mL of ethanol was transferred to a 100 mL beaker, and approximately 0.2 g of the sample powder was added to the beaker. The mixture was then subjected to ultrasonic treatment (TOMY SEIKO UD-201) for 3 minutes to prepare a dispersion. The dispersion was analyzed using laser diffraction-particle size distribution meter (Nikkiso Microtrac HRA Model9320-X100) on a volume basis. 50 The value is used as the average particle size (μm).

[0069] (3) Apparent weight The apparent specific gravity of the sample powder was determined according to JIS K6220.

[0070] (4) Magnesium content <ICP-AES method> Weigh 0.2 g of the calcium carbonate compound as the sample, moisten it with water, and add 10 mL of hydrochloric acid (a solution prepared by mixing concentrated hydrochloric acid and water in a 1:1 volume ratio) using a dispenser. Heat and dissolve the solution. After cooling, transfer the solution to a 250 mL volumetric flask and add water to bring the volume to 250 mL. Transfer 20 mL of this solution to a 50 mL volumetric flask and add water to bring the volume to 50 mL to prepare the test solution. On the other hand, transfer 20 mL of the above-mentioned 250 mL aqueous solution to a 50 mL volumetric flask, and arbitrarily add standard solutions of each element (magnesium atoms) to prepare standard solutions for calibration curves with different concentrations. Furthermore, the standard solutions for each element are 1000 ppm atomic absorption spectrometry standard solutions (commercially available).

[0071] Calibration curves with different concentrations of each additional element were set up with standard solutions and test samples in the autosampler of an inductively coupled plasma atomic emission spectrometry (ICP-AES) device (manufactured by Hitachi High Technology Co., Ltd., "SPECTROBLUEFMS36"), and the amount of magnesium atoms (ppm) was determined under the following conditions.

[0072] <Measurement Conditions> High-frequency output: 1.4 kW Carrier gas (humidification) flow rate: 0.9 L / min Plasma gas flow rate: 13.0 L / min Assist gas flow rate: 1.0 L / min Liquidity: aqueous solution Points awarded: 3 times Sample order: one sample at a time Determination method: Standard addition method Weighting of calibration curves: None Measurement wavelength: 279.553 nm (magnesium atom) (5) The 46° (aragonite) peak intensity I was calculated by XRD measurement. a Relative to 29° (calcite) peak intensity I c than After the sample powder was pressed and solidified onto a specific sample stage using a spatula, it was analyzed using an XRD apparatus (MiniFlex600-C manufactured by Rigaku Co., Ltd.) to identify it as a crystalline substance. Furthermore, at a measurement angle of 2θ, the peak appearing at approximately 29° was the main peak of calcite, and the peak appearing at approximately 46° was the main peak of aragonite. Therefore, the intensity I of the 46° (aragonite) peak was calculated. aRelative to 29° (calcite) peak intensity I c The ratio (I) a / I c ).

[0073] (6) Observation using scanning electron microscopy Double-sided tape was attached to the aluminum sample stage, and sample powder was applied from the tape using a spatula. After platinum evaporation, a 2000x magnification photograph of the sample powder particles was taken using a scanning electron microscope (FE-SEM: Hitachi S-4700 manufactured by Hitachi, Ltd.). Figures 1-2 SEM images of the embodiments and comparative examples are shown in the figure.

[0074] <Manufacturing of Calcium Carbonate Compounds> [Example 1-1] Calcium-based carbonate compounds (cubic) A sodium carbonate aqueous solution was prepared by adding 8510 g of sodium carbonate reagent (manufactured by Wako Pure Chemical Industries, Ltd.: 99.8% purity) to a 220 L SUS container with a partition that was pre-filled with 100 L of water, under stirring. Meanwhile, 1000 L of seawater (Ca) discharged from Kamishima Chemical Industry Co., Ltd., after removing magnesium hydroxide, was used... 2+ The content (0.25 g / dL) was added to a 2000 L capacity polyethylene container. 100 L of the above sodium carbonate aqueous solution was added at once while stirring. Stirring was continued for about 30 minutes to allow the reaction to proceed. The mixture was then filtered, washed with water at a ratio of about 5 times the solid content, and dried and pulverized at 110°C for 24 hours to obtain a sample powder of calcium carbonate compound.

[0075] [Examples 1-2] Calcium-based carbonate compounds (cubic) Except for adding 12.7 kg of magnesium chloride hexahydrate to 1000 L of seawater after removing magnesium hydroxide from seawater, followed by the addition of 100 L of the above-mentioned sodium carbonate aqueous solution at once, the same operation as in Example 1-1 was performed to obtain a sample powder of calcium carbonate compound.

[0076] [Examples 1-3] Calcium-based carbonate compounds (cubic) To 100 L of seawater after magnesium hydroxide removal from seawater, 10 L of the aforementioned sodium carbonate aqueous solution was added at once with stirring, and stirring was continued for approximately 30 minutes. Using this reaction solution as a seed, another 100 L of seawater after magnesium hydroxide removal from seawater was added, and 10 L of the aforementioned sodium carbonate aqueous solution was added at once with stirring, and stirring was continued for approximately 30 minutes. This series of operations was repeated a total of 10 times. Apart from these operations, the same procedures as in Examples 1-1 were performed to obtain a sample powder of a calcium carbonate compound.

[0077] [Comparative Example 1-1] Calcium carbonate compounds (needle-shaped) A mixture of commercially available quicklime powder (manufactured by Yoshimi Lime Industry Co., Ltd., the highest quality industrial quicklime), 630 g of aragonite seed powder, and 3000 g of disodium hydrogen phosphate dodecahydrate (calculated as CaO) was prepared by adding these ingredients separately to a 220 L SUS container with a partition and pre-filled with 180 L of water under stirring. The mixture was then heated to 70°C and stirred at 150 rpm using a stirrer with a single turbine blade. Exhaust gas was introduced using a test blower and simultaneously measured using a CO2 concentration meter (XP-3140 manufactured by New Cosmos Electric Co., Ltd.), which showed a CO2 concentration of 10% by volume. The exhaust gas was then introduced into the 220 L SUS container at a rate of 100 L / min using the test blower, and the reaction was allowed to proceed for 7 hours. Subsequently, the sample was filtered, washed with water approximately five times the volume of the solids, and dried and pulverized at 110°C for 24 hours to obtain a sample powder of calcium carbonate compound.

[0078] [Table 1] <Evaluation> The obtained calcium carbonate compounds were used to determine the P-funnel flow time, as well as to manufacture cement molds and conduct compressive strength tests. The results are shown in Table 3.

[0079] <P-funnel flow time> (Preparation of cement emulsion 1) 2 kg of cement (manufactured by Tokuyama Corporation, "Ordinary Portland Cement (N)") was added to 1600 mL of water over approximately 20 seconds. The mixture was then stirred for 3 minutes using a mixer (manufactured by Yamato Scientific Corporation, "Laboratory Stirrer (LR500B)"). After stirring was stopped, the mixture was allowed to stand for 3 minutes, and then manually mixed 10 times using a stirring rod (manufactured by AS ONE Corporation, "Stirring Rod (POM) ϕ10×300 mm") to produce cement emulsion 1.

[0080] (Preparation of cement emulsion 2-7) The calcium carbonate compounds of Examples 1-1 and Comparative Examples 1-1, as shown in Table 2-1 below, were added to 1600 mL of water. After stirring manually with the aforementioned stirring rod for approximately 30 seconds, the mixture was then stirred using the aforementioned mixer at 400 rpm to obtain a mixture. 2 kg of cement (Tokuyama Corporation, "Ordinary Portland Cement (N)") was added to this mixture over approximately 20 seconds, and the mixture was stirred using the aforementioned mixer for 3 minutes from the start of the addition. After stopping the stirring, the mixture was allowed to stand for 3 minutes, and then manually mixed 10 times with the aforementioned stirring rod to prepare cement emulsions 2-7.

[0081] [Table 2-1] (Preparation of cement emulsion 8-10) Except for using the calcium carbonate compounds of Examples 1-2 shown in Table 2-2 below, cement emulsions 8-10 were prepared by performing the same operations as the preparation of cement emulsions 2-7.

[0082] [Table 2-2] (Preparation of cement emulsion 11-13) Except for using the calcium carbonate compounds of Examples 1-3 shown in Tables 2-3 below in the same manner as the preparation of cement emulsions 2-7, cement emulsions 11-13 were prepared.

[0083] [Table 2-3] (P-funnel flow time test method) According to the "Test Method for Flowability of Injectable Mortar in Precast Concrete (Using the P-Function)" (JSCE-F521-1999), the flow time of the P-function was measured. With a finger pressed against the outlet of the P-function, the prepared cement emulsion (1750 mL) was injected until the mark on the P-function was reached. Simultaneously, a timer was used to start the measurement, and the time required for the cement emulsion to drain from the P-function was determined.

[0084] <Manufacturing of Cement Molded Bodies> [Example 2-1] Pour 400 mL of the prepared cement emulsion 1 up to the mark on the cylindrical polyethylene bag (approximately 50 mm in diameter × 550 mm in length × 0.05 mm in thickness). Inject as much air as possible to seal it, then suspend it in a thermostat set at 22°C. Leave it suspended in the thermostat for 28 days to allow the contents to harden, thus producing a total of 3 cement molds. The obtained cement molds are cylindrical, approximately 5 cm in diameter and 20 cm in length.

[0085] [Examples 2-2 to 2-9 and Comparative Examples 2-1 to 2-4] Except for using the cement emulsions shown in Tables 3-1 to 3-3 below, the cement molded body was manufactured by operating in the same manner as in Example 2-1.

[0086] (density) The density was determined according to JIS A 5430:2008 (apparent density test).

[0087] (Compression strength test) The compressive strength of the obtained cement molded body was determined according to JIS A 1108:2018 (compression test method for concrete).

[0088] [Table 3-1] [Table 3-2] [Table 3-3] In the cement emulsion using the calcium carbonate compound of the examples, although the content of calcium carbonate compound was increased, it did not cause a significant increase in the P-funnel flow time compared to Comparative Example 2-1 without calcium carbonate compound, and thus exhibited good fluidity. On the other hand, in Comparative Examples 2-2 to 2-4, the fluidity decreased significantly with the increase of calcium carbonate compound content.

[0089] Furthermore, in the cement molded articles of the embodiments, the compressive strength was increased compared to Comparative Example 2-1 by incorporating calcium carbonate compounds. On the other hand, in Comparative Examples 2-2 to 2-4, although calcium carbonate compounds were incorporated, the compressive strength decreased compared to the control group, Comparative Example 2-1. Moreover, although the reason for the decrease in compressive strength of Comparative Examples 2-2 to 2-4 compared to the control group is not clear, it is speculated that it is affected by the following: because the calcium carbonate compounds are needle-shaped and have increased surface energy, they agglomerate, resulting in a decrease in reinforcing effect; or because they are needle-shaped, the viscosity of the cement emulsion increases, making it difficult for air bubbles to escape, thus obtaining a cement molded article that maintains a state with residual air bubbles.

[0090] In summary, although the content of calcium carbonate compounds in the cement emulsion of the example was increased, it exhibited fluidity comparable to that of the blank group product and demonstrated excellent compressive strength when made into cement molds.

Claims

1. A calcium carbonate compound, which is cubic in shape and used in inorganic shaped articles.

2. The calcium carbonate compound as described in claim 1, wherein the average particle size obtained by laser diffraction is 2 μm or more and 25 μm or less.

3. The calcium-based carbonic acid compound of claim 1, having a BET specific surface area of 0.3 m2 / g or more 3 m2 / g or less. 2 / g or more 3 m2 / g or less. 2 / g or more 3 m2 / g or less.

4. The calcium carbonate compound as described in claim 1, wherein the apparent specific gravity is more than 1 g / mL and less than 2 g / mL.

5. The calcium carbonate compound as described in claim 1, wherein the flow time through the P funnel is 7 seconds to 10 seconds.

6. The calcium carbonate compound as described in claim 1, wherein the magnesium content is 1000 ppm or more.

7. The calcium carbonate compound as described in claim 1, wherein it is a synthetic calcium carbonate compound.

8. An inorganic shaped article comprising the calcium carbonate compound according to any one of claims 1 to 7.

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