Calcium carbonate compound and water-containing composition

Abstract

To provide a calcium-based carbonate compound and a hydrous composition capable of further reducing shrinkage of a heated surface and increase in a back surface temperature during heating when used in an inorganic molded body as a building material.SOLUTION: The calcium-based carbonate compound has a viscosity of 1000 cP or more and 2000 cP or less at 30 rpm in a state of being dispersed in water at a concentration of 33 mass%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a calcium carbonate compound and a water-containing composition. [Background technology]

[0002] Inorganic molded bodies are molded bodies that are mostly composed of inorganic substances such as hydraulic materials and siliceous materials, and because they have properties such as fire resistance, light weight, high strength, and ease of work, they are widely used as exterior wall materials for houses, roof underlayment materials, eaves ceiling materials, etc.

[0003] On the other hand, with the recent increase in environmental awareness, attempts are being made to reuse by-products and by-produced energy, such as waste, exhaust gas, and waste heat, which are generated secondarily in industrial processes.

[0004] As a technology to promote the reuse of waste materials while improving fire resistance, which is one of the important safety features required for inorganic molded bodies, a technology has been proposed in which seawater residue, which is mainly composed of calcium carbonate and magnesium hydroxide and is by-produced in the process of removing carbonates from seawater during the process of producing magnesium hydroxide from seawater, is applied to calcareous materials (JP 2012-116685 A). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-116685 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even with the above techniques, shrinkage of the heated surface and an increase in the temperature of the back surface may occur during heating, and there is a demand for further improvement in the fire resistance of inorganic molded bodies as building materials.

[0007] Furthermore, carbon dioxide is becoming widely recognized as a greenhouse gas, and the reuse and reduction of carbon dioxide emissions as a secondary product from industrial processes has become an urgent issue.

[0008] An object of the present invention is to provide a calcium carbonate compound and a water-containing composition that can exhibit a higher level of fire resistance when used in an inorganic molded body as a building material. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by the following configuration, and have thus completed the present invention.

[0010] In one embodiment, the present invention provides The present invention relates to a calcium carbonate compound having a viscosity of 1000 cP or more and 2000 cP or less at 30 rpm when dispersed in water at a concentration of 33% by mass.

[0011] The calcium carbonate compound has a viscosity at 30 rpm within a specific range when dispersed at a predetermined concentration, and therefore can exhibit a higher level of fire resistance when used in inorganic molded articles. Although the reason for this is unclear, it is presumed as follows.

[0012] The inventors have conducted further research into applying the dispersion of calcium carbonate compounds obtained in the manufacturing process of synthetic calcium carbonate compounds directly to the manufacturing process of inorganic molded bodies, and have found that if the dispersion has the above-mentioned specific viscosity, it is possible to suppress the shrinkage of the heating surface and the increase in the back surface temperature during heating.

[0013] The dispersion liquid in which the calcium carbonate compound is dispersed has a relatively high viscosity within a specific range. This is presumably due to the reduced aggregation of the calcium carbonate compound, resulting in a high degree of dispersion in the form of primary particles. By directly incorporating the dispersion liquid containing the calcium carbonate compound in the form of primary particles during the production of an inorganic molded body, the calcium carbonate compound is uniformly dispersed in the form of primary particles in the inorganic molded body. As a result, the calcium carbonate compound functions as a so-called reinforcing material, thereby suppressing shrinkage of the heated surface. Furthermore, the uniform dispersion of the low-thermal-conductivity calcium carbonate compound improves the insulation properties of the inorganic molded body in the thickness direction, thereby suppressing an increase in the back surface temperature.

[0014] It is believed that these combined effects enable the shrinkage of the heated surface and the rise in temperature of the back surface during heating to be suppressed to a higher degree, allowing the inorganic molded body as a whole to exhibit a high level of fire resistance.

[0015] In this specification, the term "calcium-based 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-based carbonate compound is preferably 80 mass% or more. XRF (X-ray fluorescence analysis) can be suitably employed as a method for measuring the calcium carbonate content in the calcium-based carbonate compound.

[0016] In one embodiment, the viscosity of a dispersion of the calcium carbonate compound dispersed in water at a concentration of 33% by mass is preferably 1000 cP or more and 2500 cP or less at 6 rpm, which improves the uniformity of the dispersion of the calcium carbonate compound and enables higher levels of suppression of shrinkage of the heating surface and increase in temperature of the back surface during heating.

[0017] In one embodiment, the viscosity μ of a dispersion liquid in which the calcium carbonate compound is dispersed in water at a concentration of 33% by mass is 6 rpm and the viscosity μ of a dispersion liquid in which the calcium carbonate compound is dispersed in water at a concentration of 33% by mass is 6 rpm. 30The ratio μ6 / μ 30 is preferably 1.0 or more and 2.5 or less. This reduces the thixotropy of the dispersion, and the viscosity is maintained at a certain level, regardless of whether the stirring speed or shear force is high or low, without a large difference between the two. As a result, deformation and deterioration of the molded body when force is applied and released, such as during molding or pressing in the inorganic molded body production process, are suppressed, and an inorganic molded body with excellent fire resistance can be produced.

[0018] In one embodiment, the aspect ratio of the average major axis to the average minor axis of the calcium carbonate compound is preferably 2 or more and 19 or less. In one embodiment, the average particle size of the calcium carbonate compound measured by laser diffraction method is preferably 1.1 μm or more and 12.5 μm or less. 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. By satisfying one or a combination of these requirements, a specific range of viscosity can be suitably imparted to the dispersion of the calcium carbonate compound.

[0019] In another embodiment, the present invention provides The present invention relates to a water-containing composition containing water and the calcium carbonate compound.

[0020] The water-containing composition can have a viscosity within the above-mentioned range, and therefore can maintain a high degree of primary particle state of the calcium carbonate compound. Therefore, when the water-containing composition is applied to the production of an inorganic molded body, the resulting inorganic molded body can be highly suppressed from shrinking on the heated surface and from increasing in temperature on the back surface during heating.

[0021] In one embodiment, the water content of the water-containing composition may be 40% by mass or more and 99% by mass or less, which allows the water-containing composition to take the form of a so-called slurry.

[0022] In one embodiment, the water content of the water-containing composition may be 5% by mass or more and 60% by mass or less, which allows the water-containing composition to take the form of a so-called cake.

[0023] In one embodiment, the hydrous composition is preferably obtained without drying in the production process of the synthetic calcium carbonate compound. By using a synthetic calcium carbonate compound that is a reaction product of calcium hydroxide and carbon dioxide as the calcium carbonate compound, carbon dioxide generated secondarily in the industrial process can be reused, which can contribute to reducing carbon dioxide emissions throughout the industrial process. Furthermore, because the hydrous composition is obtained without drying, it is possible to further reduce carbon dioxide emissions.

[0024] The present invention, in yet another embodiment, comprises: The present invention relates to an inorganic formed body containing the calcium carbonate compound.

[0025] The inorganic formed body contains the calcium carbonate compound, and therefore can exhibit a higher level of fire resistance.

[0026] In yet another embodiment, the present invention comprises: The present invention relates to a method for producing an inorganic molded body, which includes a step of molding an inorganic composition containing the water-containing composition.

[0027] In this production method, the water-containing composition is subjected to the molding step as it is, so that an inorganic molded article having excellent fire resistance can be efficiently produced. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is an SEM photograph of a calcium carbonate compound obtained from the water-containing composition of Example 1-1 of the present invention. [Figure 2] 1 is a SEM photograph of a calcium carbonate compound obtained from the water-containing composition of Example 1-2 of the present invention. [Figure 3]FIG. 2 is a partial perspective view schematically showing a heating tester. DETAILED DESCRIPTION OF THE INVENTION

[0029] The calcium carbonate compound and water-containing composition according to one embodiment of the present invention will be described below, but the present invention is not limited to these embodiments.

[0030] <Calcium carbonate compounds> The calcium carbonate compound according to this embodiment is a calcium carbonate compound having a viscosity of 1000 cP to 2000 cP at 30 rpm when dispersed in water at a concentration of 33% by mass. The viscosity at 30 rpm is preferably 1100 cP to 1900 cP, and more preferably 1200 cP to 1800 cP. This improves workability and allows the calcium carbonate compound to maintain a high degree of primary particle state. When the dispersion is used to produce an inorganic molded product, shrinkage of the heated surface and an increase in the backside temperature during heating can be reduced.

[0031] The viscosity at 6 rpm of a dispersion in which the calcium carbonate compound is dispersed in water at a concentration of 33% by mass is 1000 cP or more and 2500 cP or less. The viscosity at 6 rpm is preferably 1100 cP or more and 2400 cP or less, and more preferably 1200 cP or more and 2300 cP or less. This improves the uniformity of the dispersion of the calcium carbonate compound. When the dispersion is used to produce an inorganic molded product, shrinkage of the heated surface and increase in the backside temperature during heating can be suppressed to a higher level.

[0032] The viscosity μ at 6 rpm of the dispersion in which the calcium carbonate compound is dispersed in water at a concentration of 33% by mass is 30 The ratio μ6 / μ 30 The ratio μ6 / μ is 1.0 or more and 2.5 or less. 30is preferably 1.0 or more and 2.2 or less, and more preferably 1.0 or more and 1.8 or less, thereby making it possible to suppress the occurrence of thixotropy in the dispersion state and to prevent deformation and deterioration of the molded body when force is applied and released in the inorganic molded body production process.

[0033] 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 an aspect ratio as described below, it is preferable that the calcium carbonate compound contains at least an aragonite type crystal structure.

[0034] The aspect ratio of the average major axis to the average minor axis of the calcium carbonate compound is preferably 2 or more and 19 or less, more preferably 2.5 or more and 17 or less, and even more preferably 3 or more and 15 or less. By setting the aspect ratio of the calcium carbonate compound within the above range, the dispersion of the calcium carbonate compound can preferably have a viscosity within the above range. Furthermore, a calcium carbonate compound with a high aspect ratio effectively functions as a reinforcing material, thereby suppressing shrinkage on the heated surface and an increase in the back surface temperature, thereby enabling the inorganic molded body as a whole to exhibit excellent fire resistance.

[0035] When the inorganic molded body is produced by a papermaking method, the aspect ratio of the calcium carbonate compound is preferably 4 to 19, more preferably 6 to 18, and even more preferably 8 to 17. When the inorganic molded body is produced by an extrusion molding method, the aspect ratio of the calcium carbonate compound is preferably 2 to 12, more preferably 2.5 to 10, and even more preferably 3 to 8.

[0036] 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, 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. This allows the dispersion of the calcium carbonate compound to have a viscosity within the above range. Furthermore, the dispersibility of the calcium carbonate compound can be improved, and shrinkage of the heating surface can be efficiently suppressed.

[0037] The average major axis of the calcium carbonate compound, as observed with 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. This allows the calcium carbonate compound dispersion to have a suitable viscosity within the above range. Furthermore, aggregation of the calcium carbonate compounds with each other or between the calcium carbonate compound and other components is suppressed, and as a result, shrinkage of the heating surface and an increase in the back surface temperature during heating can be suppressed to a higher level.

[0038] 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 9m 2 / g or less is more preferable, and 2 / g or more 8m 2 This makes it possible to improve the dispersibility of the calcium carbonate compound, and as a result, it is possible to suppress the shrinkage of the heating surface and the rise in the temperature of the back surface during heating to a higher degree.

[0039] In the X-ray diffraction measurement of the calcium carbonate compound, the peak intensity of aragonite I a Calcite peak intensity I c Ratio to I a / I cis preferably 0.02 or more, more preferably 0.20 or more, and even more preferably 1.00 or more. This allows a high aspect ratio to be efficiently imparted to the calcium carbonate compound, and the viscosity of the dispersion can be appropriately controlled. In addition, the fire resistance of the inorganic molded body can be improved to a higher level.

[0040] The calcium-based carbonate compound is preferably a synthetic calcium-based carbonate compound. By using a synthetic calcium-based carbonate compound, which is a reaction product of calcium hydroxide and carbon dioxide, as the calcium-based carbonate compound, it is possible to reuse carbon dioxide that is secondarily generated in the industrial process, thereby contributing to a reduction in carbon dioxide emissions throughout the industrial process. In addition, in the process of producing magnesium hydroxide from seawater, the calcium-based carbonate compound produced as a by-product in the process of removing carbonates from seawater and seawater residue containing magnesium hydroxide as its main components can also be used as a calcium-based carbonate compound source.

[0041] <Water-containing composition> The water-containing composition according to this embodiment contains water and the calcium carbonate compound. Since the water-containing composition contains the calcium carbonate compound having the above-described structure, the water-containing composition can have a viscosity within the specific range.

[0042] The water content of the water-containing composition may be 40% by mass or more and 99% by mass or less, 50% by mass or more and 99% by mass or less, or 60% by mass or more and 99% by mass or less, thereby allowing the water-containing composition to take the form of a so-called slurry.

[0043] The water content of the water-containing composition may be 5% by mass or more and 60% by mass or less, 10% by mass or more and 60% by mass or less, or 15% by mass or more and 60% by mass or less, which allows the water-containing composition to take the form of a so-called cake.

[0044] The method for measuring the water content of the water-containing composition is as described in the Examples.

[0045] The hydrous composition is preferably obtained without drying in the production process of the synthetic calcium carbonate compound (described below). By using a synthetic calcium carbonate compound that is a reaction product of calcium hydroxide and carbon dioxide as the calcium carbonate compound, carbon dioxide generated secondarily in the industrial process can be reused, which contributes to reducing carbon dioxide emissions throughout the industrial process. Furthermore, since the hydrous composition is obtained without drying, it is possible to further reduce carbon dioxide emissions.

[0046] The water-containing composition may contain, in addition to the calcium carbonate compound, known optional components such as surfactants, viscosity modifiers, other metals or metal salts, acids, and alkalis.

[0047] <Method for producing calcium carbonate compound and method for producing water-containing composition> The method for synthesizing calcium carbonate compounds is not particularly limited, and known production methods can be used. A typical example is the carbon dioxide method, in which carbon dioxide gas is blown into milk of lime (a slurry prepared by adding an excess of slaked lime to a saturated aqueous solution of slaked lime) to carbonate the mixture. The carbon dioxide gas used in the carbon dioxide method can be the flue gas from a lime calciner, a boiler, a waste incinerator, or the like, located near a calcium carbonate compound production plant.

[0048] Known methods can also be used to impart a predetermined aspect ratio to a calcium carbonate compound based on the carbon dioxide gas method. Specific examples of such methods include a method for producing a calcium carbonate compound by adjusting the amount of carbon dioxide gas at each stage of the carbonation process, a method for producing a calcium carbonate compound by heating during the carbonation process, a method for producing a calcium carbonate compound by using needle-shaped light calcium carbonate compound as seed crystals in a slaked lime slurry and introducing carbon dioxide gas into the slurry to grow the seed crystals to a desired particle size through a carbonation reaction, a method for producing a calcium carbonate compound by adding an aragonite-type needle-shaped calcium carbonate compound to a slaked lime slurry and carrying out a carbonation reaction while stirring at a high stirring power, a method for producing an aragonite-type calcium carbonate compound by adding a phosphate compound, a method for producing a calcium carbonate compound by adding a sulfate compound to obtain a spindle-shaped calcium carbonate compound, a method for producing an aragonite-type calcium carbonate compound by using a slaked lime slurry prepared with an alkaline aqueous solution, and a method for producing an aragonite-type calcium carbonate compound by using a slaked lime slurry prepared with water containing magnesium ions. By using one or a combination of two or more of these methods, a calcium carbonate compound having an aragonite-type crystal structure can be efficiently produced.

[0049] Among these, a preferred method for producing a calcium carbonate compound having a high aspect ratio and oil absorption is a method for producing a calcium carbonate compound (hereinafter also referred to as the "seed crystal method") in which needle-shaped synthetic calcium carbonate compound with 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.

[0050] In the seed crystal method, the amount of seed crystals to be added 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).

[0051] In the seed crystallization method, the concentration of carbon dioxide gas varies depending on the type of exhaust gas generated from each combustion engine, but when carbonation efficiency is taken into consideration, it is preferably 1% by volume or more, more preferably 5% by volume or more, and even more preferably 10% by volume or more. When carbonation efficiency and production capacity are taken into consideration, the flow rate of carbon dioxide gas is preferably 10 L / min to 200 L / min, more preferably 30 L / min to 150 L / min, and even more preferably 60 L / min to 120 L / min per 10 kg of charged raw material CaO.

[0052] In the seed crystallization method, the carbonation temperature (the temperature of the slaked lime slurry) is preferably 40°C or higher and 100°C or lower, more preferably 50°C or higher and 90°C or lower, and even more preferably 60°C or higher and 80°C or lower.

[0053] In the seed crystal method, it is preferable to allow the carbonation to proceed in the presence of a phosphate. , Li Examples include 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.

[0054] In the seed crystal method, the amount of phosphate to be added is preferably 1 part by mass or more and 25 parts by mass or less, more preferably 4 parts by mass or more and 18 parts by mass or less, and even more preferably 6 parts by mass or more and 12 parts by mass or less, per 100 parts by mass of slaked lime (calculated as CaO).

[0055] If a high aspect ratio is not required, a calcium carbonate compound can also be produced without adding seed crystals or phosphate.

[0056] By the above procedure, a calcium carbonate compound in the form of a dispersion can be produced. In addition, a water-containing composition can be obtained by using the dispersion containing the calcium carbonate compound in the form of a slurry or cake without drying.

[0057] The water content of the obtained water-containing composition may be adjusted by adding water to the water-containing composition, filtering or pressing the water-containing composition to remove water, or by combining these methods.

[0058] In addition to the carbon dioxide gas method, a waste seawater utilization method is also preferred from the viewpoints of waste utilization and carbon dioxide reduction, 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 carbon dioxide gas is then blown into the waste seawater. Furthermore, as described above, in the process of producing magnesium hydroxide from seawater, calcium carbonate compounds by-produced in the process of removing carbonates from seawater and seawater residue mainly composed of magnesium hydroxide can also be used as a calcium carbonate compound source. The water-containing compositions obtained by these methods may be washed with water or the water content may be adjusted as described above.

[0059] <Uses of calcium carbonate compounds and water-containing compositions> The calcium carbonate compound and the water-containing composition may be used in any application, including, for example, as a functional agent for inorganic molded bodies, such as building materials, and as a filler for resins. Hereinafter, an embodiment in which the calcium carbonate compound and the water-containing composition are used in an inorganic molded body will be described.

[0060] The inorganic molded body is preferably formed from an inorganic composition containing a hydraulic material, a siliceous material, a reinforcing fiber material, and a calcium carbonate compound.

[0061] (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, and dihydrate gypsum. Examples of slag include blast furnace slag and converter slag. These hydraulic materials can be used alone or in combination of two or more.

[0062] 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 of the inorganic molded body, such as bending strength and peel strength, and also to prevent the inorganic molded body from becoming too high in bulk density, thereby improving workability during construction.

[0063] (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 Examples of suitable siliceous materials include materials containing a large amount of SiO2, such as lastonite and lightweight aggregates (e.g., fly ash balloons, perlite, shirasu balloons, glass foam, etc.). 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, as described below.

[0064] 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 specific gravity, water absorption rate, dimensional stability, etc. of the inorganic molded body within the desired range. Incidentally, as the siliceous material, perlite, fly ash balloons, shirasu balloons, etc., having a unit volume mass of 0.5 g / cm are preferred. 3 When blending the following lightweight aggregates, in order to prevent the bulk density from becoming too light and weakening 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.

[0065] (reinforcing fiber material) Examples of reinforcing fiber materials that can be used include pulps such as softwood pulp, hardwood pulp, fibrillated pulps thereof, and pulp obtained by defibrating waste paper, organic reinforcing fiber materials such as vinylon fiber, acrylonitrile fiber, and polypropylene fiber, and inorganic reinforcing fiber materials such as rock wool and glass fiber. These reinforcing fiber materials can be used alone or in combination of two or more.

[0066] 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 achieve a sufficient reinforcing effect while suppressing the protrusion of fibers from the surface of the inorganic molded body, thereby improving 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.

[0067] (Calcium carbonate compounds) As the calcium carbonate compound, the above-mentioned calcium carbonate compound that has not been dried can be suitably used. In other words, it is preferable to use the calcium carbonate compound in the form of an undried water-containing composition for producing an inorganic molded body.

[0068] The content (solid 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 materials constituting the inorganic molded body. By blending a low thermal conductive calcium carbonate compound in the above content range, the heat insulating properties in the thickness direction of the inorganic molded body are improved, and the rise in the back surface temperature can be suppressed to a high level.

[0069] (optional ingredient) In addition to the above materials, various materials can be blended into the inorganic molded body depending on the purpose, such as hollow resin bodies, wood chips, wood flour, resin powder, antifoaming agents, flocculants, water repellents, thickeners (methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, etc.), dispersants, etc. In addition, recycled materials made by crushing scraps generated during the processing of the inorganic molded body can be appropriately added and used.

[0070] (Method for producing inorganic molded body) The method for producing the inorganic molded body according to this embodiment is not particularly limited and includes a step of molding an inorganic composition containing the hydrous composition. Examples of molding methods that can be used include commonly used papermaking, extrusion, flow-on molding, casting, and press (compression) molding. The inorganic molded body can be obtained by subjecting a green sheet molded by these methods to a dehydration step such as press dehydration and / or a patterning step such as embossing, followed by a curing step such as room temperature curing, steam curing, or autoclave curing. A drying step may then be performed, and a shaping step or painting step may be performed as necessary.

[0071] (Uses of inorganic molded bodies) The uses of the inorganic molded body are not particularly limited, and it can be suitably used as a performance maintaining material such as wall materials, floor materials, roofing materials, various boards, exterior decorative members, interior and exterior finishing materials such as building materials, sealing materials, heat insulating materials, sound absorbing materials, waterproofing materials, etc. The inorganic molded body is preferably a cementitious molded body containing a cementitious material, more preferably a calcium silicate molded body. Of these, the molded body is more preferably a molded board. [Example]

[0072] The present invention will be described in detail below using examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. Measurements and evaluations of physical properties, etc. were carried out as follows.

[0073] <Evaluation of calcium carbonate compounds> The water-containing compositions and calcium carbonate compounds obtained in the examples and comparative examples were analyzed as follows. The analytical results are shown in Table 1 and Figures 1 and 2. In Table 1, arrows indicate results that are the same as those in the left column.

[0074] (1) BET specific surface area The sample powder was pretreated in an 8-well preheat unit (MOUNTECH) at approximately 130°C for approximately 30 minutes under a nitrogen gas atmosphere. The BET specific surface area (m) was measured by nitrogen gas adsorption using a Macsorb HM Model-1208 (MOUNTECH) BET specific surface area measuring device. 2 / g) was measured. Note that in order to measure the BET specific surface area, it is necessary to measure the sample in a dried powder form. Therefore, in the case of sample cakes or sample slurries, these were dried at 110°C for 24 hours to prepare sample powder for BET specific surface area measurement.

[0075] (2) Average particle size by laser diffraction method 50 mL of ethanol was placed in a 100 mL beaker, and approximately 0.3 g of sample cake, approximately 0.6 mL of sample slurry, and approximately 0.2 g of sample powder were placed in the 100 mL beaker. The mixture 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).

[0076] (3) Calculation of the 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 by tracing it with a spatula. After platinum deposition, particle images of the sample powder were photographed at 2,000 magnifications using a scanning electron microscope (FE-SEM: S-4700, manufactured by Hitachi, Ltd.). Figures 1 and 2 show SEM images. Figure 1 is an SEM image of the calcium carbonate compound obtained from the hydrous composition of Example 1-1. Figure 2 is an SEM image of the calcium carbonate compound obtained from the hydrous composition of Example 1-2. Using image analysis software (Image J), ​​20 particles were randomly selected from the SEM images, and the average values ​​of the long diameter, short diameter, and aspect ratio (ratio of the long diameter to the short diameter) of the primary particles were calculated. Note that for observation using a scanning electron microscope, the sample powder must be dried. Therefore, in the case of sample cakes or sample slurries, these were dried at 110 °C for 24 hours to prepare sample powders for scanning electron microscope observation.

[0077] (4) 46° (aragonite) peak intensity I by XRD measurement a 29° (calcite) peak intensity I c Calculating the ratio to The sample powder was pressed and fixed onto a designated sample stage with a spatula, and then measured using an XRD device (MiniFlex600-C manufactured by Rigaku Corporation) to identify the crystalline material. At the measurement angle 2θ, the peak appearing at approximately 29° is the main peak of calcite, and the peak appearing at approximately 46° is the main peak of aragonite. From this, the 46° (aragonite) peak intensity I a 29° (calcite) peak intensity I c Ratio to (I a / I c ) was determined. Note that XRD measurement requires that the sample be in a dried powder form. Therefore, in the case of sample cakes or sample slurries, these were dried at 110°C for 24 hours to prepare sample powder for XRD measurement.

[0078] (5) Dynamic viscosity, static viscosity and thixotropy The dynamic viscosity, static viscosity, and thixotropy value of the slurry prepared to a predetermined concentration were measured. That is, using a B-type viscometer, the viscosity at a rotor rotation speed of 30 rpm (dynamic viscosity) and the viscosity at 6 rpm (static viscosity) were measured. The thixotropy value was calculated by multiplying the viscosity μ6 at 6 rpm by the viscosity μ6 at 30 rpm. 30 The value obtained by dividing by (μ6 / μ 30 ) was calculated.

[0079] <Production of a water-containing composition containing a calcium carbonate compound> [Example 1-1] Calcium carbonate compound (aspect ratio 10.4) A mixed slurry of 6980 g of slaked lime powder (calculated as CaO), 630 g of aragonite seed crystal powder, and 500 g of disodium hydrogen phosphate dodecahydrate was prepared by stirring a 220 L stainless steel vessel equipped with a baffle and containing 180 L of water. The mixture was then heated to 70 °C and stirred at 150 rpm using a stirrer equipped with a single turbine blade. A flue gas extraction pipe was connected to the exhaust outlet of an LNG-fueled steam production boiler. A test blower was used to draw in the exhaust gas. Measurements using a CO2 meter (XP-3140, manufactured by New Cosmos Electric Co., Ltd.) revealed a CO2 concentration of 10% by volume. The test blower was used to introduce the exhaust gas into the 220 L stainless steel vessel at a rate of 100 L / min, and the carbonation reaction was carried out for 7 hours. The mixture was then filtered through a test filter press and washed with approximately five times the amount of water relative to the solid content to obtain a sample cake with a CaCO3 concentration of 75% by mass. A portion of the sample cake was extracted for evaluation of calcium carbonate, and the extracted sample cake was used as is without drying. The sample cake was also emulsified in water to prepare a calcium carbonate sample slurry with a CaCO3 concentration of 33% by mass.

[0080] [Example 1-2] Calcium carbonate compound (aspect ratio 2.7) A sample cake and a sample slurry of calcium carbonate compounds were obtained in the same manner as in Example 1-1, except that 7,170 g of milk of lime (calculated as CaO) was prepared, aragonite seed crystals and disodium hydrogen phosphate dodecahydrate were not added, and the reaction temperature was set at 40°C.

[0081] [Comparative Example 1-1] Calcium carbonate compound (aspect ratio 10.4) The same operations as in Example 1-1 were carried out up to the carbonation reaction, after which the mixture was filtered with a test filter press, washed, dried at 110°C for 24 hours, and pulverized to obtain a calcium carbonate powder sample.

[0082] [Comparative Example 1-2] Calcium carbonate compound (aspect ratio 2.7) The same operations as in Example 1-2 were carried out up to the carbonation reaction, after which the mixture was filtered through a test filter press, washed, dried at 110°C for 24 hours, and pulverized to obtain a calcium carbonate powder sample.

[0083] [Table 1]

[0084] <Production of inorganic molded body> Inorganic molded bodies were produced by papermaking and extrusion molding according to the following procedures. The amounts of the components used are all expressed in parts by mass unless otherwise specified. In the table below, "-" indicates that the corresponding component was not used.

[0085] [Production Example 1-1] Production of inorganic molded body by papermaking method The materials shown in Table 2 below were placed in a plastic container and mixed by stirring to obtain a raw material slurry. The sample slurry of Example 1-1 (CaCO3 concentration: 33% by mass) was used as the calcium carbonate compound, in an amount corresponding to the calcium carbonate compound shown in Table 2. The raw material slurry was divided and placed in a filter lined with felt, and a laminate (long side 28 mm × short side 24 mm × thickness 14 mm) was produced while suction filtering was performed using 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.

[0086] [Production Example 1-2] Production of inorganic molded body by papermaking method An inorganic formed body was obtained in the same manner as in Production Example 1-1, except that the sample slurry of Example 1-2 (CaCO3 concentration: 33 mass %) was used as the calcium carbonate compound.

[0087] [Comparative Production Example 1-1] Production of inorganic molded body by papermaking method An inorganic formed body was obtained in the same manner as in Production Example 1-1, except that the sample powder of Comparative Example 1-1 was used as the calcium carbonate compound.

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

[0089] <Evaluation of inorganic molded bodies> The inorganic molded bodies produced by papermaking in the Production Examples and Comparative Production Examples were evaluated as follows. The results are shown in Tables 2 and 3.

[0090] (bulk density) The bulk density was measured in accordance with JIS A 5430.

[0091] (heating test) The heating test was carried out using the following equipment and procedure. Figure 5 is a partial perspective view that shows a schematic diagram of the heating tester. As shown in Figure 5, an electric heater was used as the heat source, and fireproof material was installed between the test specimen and the heat source to stabilize the temperature at around 900°C, and a thermocouple was used to measure the temperature on the backside of the test specimen. Specifically, an electric heater (1.2 kW heater) was used as the heat source, and a K-type thermocouple and a temperature controller were connected. Each thermocouple was also connected to a data logger. The distance between the heating surface of the test specimen and the heat source was fixed at approximately 70 mm.

[0092] The test procedure was as follows. (1) A scrap board was placed, preheated to 902°C, and then heated once. (2) The specimen was inserted after the heated surface had cooled to below 200°C. (3) A thermocouple was placed in the center of the back surface (top surface in the figure) of the test specimen, 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 sample was left for the specified time (45 minutes), after which the temperatures on the front and back sides were recorded with a data logger. During this time, the temperature setting of the electric heater was set to 902°C on the heating surface side, and the temperature 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 specimen was 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 heating surface were measured with a vernier caliper. The area of ​​the heating surface (mm 2 ) was calculated, and the heating surface shrinkage (%) was calculated based on the following formula. Heating surface shrinkage (%) = {|S1-S0| / S0} x 100 (where S0 is the area of ​​the heated surface before the test, and S1 is the area of ​​the heated surface after the test.)

[0093] [Table 2]

[0094] The inorganic molded body of the manufacturing example was superior to the comparative manufacturing example in both the heated surface shrinkage and the back surface temperature rise. Furthermore, the inorganic molded body of the manufacturing example had a strength sufficient for practical use and did not develop cracks after heating (not shown).

[0095] [Production Example 2-1] Production of inorganic molded body by extrusion molding method The materials shown in Table 3 below were charged into an omnimixer and dry-mixed for 3 minutes. The sample cake from Example 1-1 (75% by mass in CaCO3 concentration) was used as the calcium carbonate compound, with the amount of calcium carbonate compound shown in Table 2. Next, water was added and wet-mixed for 2 minutes. The wet-mixed raw materials were kneaded in an Ishikawa extruder and then extrusion-molded using the Ishikawa extruder. This produced a compact (long side 600 mm x short side 190 mm x thickness 13 mm). After obtaining the compact, it was placed in a thermo-hygrostat set at 60°C / 98% for primary curing, and then autoclave-cured for 12 hours at a pressure of 9 kgf. Both sides of the compact were sanded with a sander to reduce the thickness to 12 mm, producing an inorganic compact.

[0096] [Production Example 2-2] Production of inorganic molded body by extrusion molding method An inorganic formed body was obtained in the same manner as in Production Example 2-1, except that the sample cake of Example 1-2 (CaCO3 concentration: 75 mass %) was used as the calcium carbonate compound.

[0097] [Comparative Production Example 2-1] Production of inorganic molded body by extrusion molding method An inorganic formed body was obtained in the same manner as in Production Example 2-1, except that the sample powder of Comparative Example 1-1 was used as the calcium carbonate compound.

[0098] [Comparative Production Example 2-2] Production of inorganic molded body by extrusion molding method An inorganic formed body was obtained in the same manner as in Production Example 2-1, except that the sample powder of Comparative Example 1-2 was used as the calcium carbonate compound.

[0099] <Evaluation of inorganic molded bodies> The inorganic molded articles produced by extrusion molding in the Production Examples and Comparative Production Examples were evaluated as follows. The results are shown in Table 3.

[0100] (bulk density) The bulk density was measured in accordance with JIS A 5430.

[0101] (heating test) The measurement was carried out in the same manner as in the papermaking method.

[0102] [Table 3]

[0103] In the inorganic molding of the manufacturing example, the heating surface shrinkage and Backside temperature rise In addition, the inorganic molded body of the manufacturing example had a strength that could withstand practical use, and no cracks were generated after heating (not shown).

Claims

1. A water-containing composition containing water and a calcium carbonate compound, A water-containing composition, wherein the calcium carbonate compound is dispersed in water at a concentration of 33% by mass, and the viscosity of the dispersion at 30 rpm is 1000 cP or more and 2000 cP or less.

2. 2. The water-containing composition according to claim 1, wherein the viscosity of a dispersion of the calcium carbonate compound dispersed in water at a concentration of 33% by mass at 6 rpm is 1000 cP or more and 2500 cP or less.

3. The viscosity μ of the dispersion liquid in which the calcium carbonate compound is dispersed in water at a concentration of 33% by mass at 6 rpm 6 Viscosity μ at 30 rpm 30 Ratio to μ 6 / μ 30 The water-containing composition according to claim 2, wherein the σ is 1.0 or more and 2.5 or less.

4. The aqueous composition described in claim 1, wherein the aspect ratio of the average major axis of the calcium carbonate compound to the average minor axis is 2 or more and 19 or less.

5. The hydrous composition described in claim 1, wherein the average particle diameter of the calcium carbonate compound measured by laser diffraction method is 1.1 μm or more and 12.5 μm or less.

6. The hydrous composition described in claim 1, wherein the average long diameter of the calcium carbonate compound as observed with a scanning electron microscope is 0.5 μm or more and 25 μm or less.

7. The water-containing composition according to claim 1, having a water content of 40% by mass or more and 99% by mass or less.

8. The water-containing composition according to claim 1, having a water content of 5% by mass or more and 60% by mass or less.

9. 2. The water-containing composition according to claim 1, which is obtained without drying in the production process of the synthetic calcium carbonate compound.

10. A method for producing an inorganic molded body, comprising the step of molding an inorganic composition containing the water-containing composition according to claim 1.

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