KR800001114B1 - Shaped bodies of calcium silicate and process for producing the same - Google Patents

Abstract

The titled silica bodies consist of foshagite and/or xonotlite and the 2 acicular crystals form 3-dimensional networks in a spherical shape. The spheres have shell thickness 0.3-10μm, outside diam. 10-80μm, and d. <= 0.13g/cm3. Thus, SiO2 was added to a CaO slurry. The mixt. was autoclaved 8hr at 191≰C and 12kg/cm2 to prep. a compd. having xonotlite structure and av. diam. 38μm, d. 0.1 g/cm3, and av. shell thickness 2.4μm.

Description

Method for producing a molded article of calcium silicate

FIG. 1 is an electron micrograph of magnified 30000 × of xonotlite having a reverse growth rate of at least 15, prepared in Example 1. FIG.

2 is an electron micrograph of β-wolastonite magnified at the same rate.

3 is an electron micrograph of Xanotolite having an inverse growth rate of less than 15 magnified at the same magnification as in FIG.

4 is an electron micrograph of magnified β-walllastonite obtained by calcining xonotite at 1000 ° C for 3 hours at the same magnification.

5 is an optical micrograph of a spherical secondary particle prepared in Example 1 at a magnification of 200X.

6 is a scanning electron micrograph of the same secondary particle at magnification 3000X.

7 is an electron micrograph showing the same secondary particles at 15000 × magnification.

FIG. 8 is an optical micrograph of a lamella sample prepared by incorporating the secondary particles into a synthetic resin and slicing the lumps produced by microscopic examination at a magnification of 1100X.

9 is an electron micrograph of the same sample magnified at 8700X.

FIG. 10 is a scanning electron micrograph at a magnification of 2000X of a segmental end of a molded article of the present invention having a volume density of 0.2 g / cm ³ .

11 is a micrograph showing the segmental end of the molded article produced in Example 1. FIG.

12 is an X-ray rotation analysis curve of a slurry consisting of crystals of xenonotrite.

Figure 13 is a confirmatory test curve by X-ray diffraction analysis of β- wollastonite.

14 is a scanning electron micrograph showing the segmental end of the molded article of the present invention having a volume density of 0.4 g / cm ³ or more.

FIG. 15 is a micrograph showing a Schistose structure in which a hollow spherical secondary crystal overlaps a planar layer when the volume density increases to 0.4 g or more.

16 is an X-ray diffraction curve of the slurry prepared in Example 4. FIG.

FIG. 17 is an electron micrograph of a Fos Hagite crystal at magnification 15000 ×.

TECHNICAL FIELD This invention relates to the manufacturing method of the molded object of calcium silicate.

Calcium silicate has been widely used as a refractory material, thermal insulation material, filler material, absorbent, reinforcing material, pigment, building material and the like. Calcium siliconate may find wider application. This is because calcium silicate has characteristics of high specific strength, high fire resistance and thermal insulation, light weight and excellent non-conductivity. These properties are mainly attributable to the following two aspects, namely, the shape of the calcium silicate crystal itself and the structure of the shaped body.

Kubo, one of the inventors of the present invention, conducts research on calcium silicate from these two viewpoints, and when calcium silicate crystals aggregate into secondary particles having a very unique structure, these particles form a lightweight calcium silicate molded body. Formed and found to increase in strength. This finding has already been patented in US Pat. No. 3,679,446.

The U.S. patent describes a substantially spherical secondary particle composed of thin necked calcium carbonate crystals interconnected in a three-dimensional form. These particles have an outer diameter of 10 to 150 µm and have a large number of thin neck-shaped calcium carbonate crystals protruding from the surface of the whiskers. Calcium silicate molded bodies produced from the secondary particles have low volume density and high strength.

The present inventors continued to study the structure of the secondary particles of calcium silicate, the state of the calcium silicate crystals and their structure and state and the basis of the calcium silicate molded body. When calcium crystals were made into secondary particles with a unique structure, they found that the particles produced lighter and stronger calcium silicate shaped bodies. The inventors also found that when the molded body was fired at 1000 ° C., a product having a significantly improved residual strength was obtained as compared to the existing calcium silicate molded body of this type.

An object of the present invention is to provide a molded product of calcium carbonate, which has a significantly lower volume density and higher strength than that of a calcium carbonate molded product known to date, and has a significantly higher residual strength than that of calcium carbonate, which has been previously available when fired at 1000 ° C. It is to provide.

Another object is to provide a calcium silicate molded article having a higher strength than the known molded articles when the volume density is the same as that of the conventional calcium silicate molded articles.

Still another object is to provide a method for producing a calcium silicate molded article having a lower volume density and a higher strength than a known molded molded product of calcium silicate, and having a significantly higher residual strength when fired at 1000 ° C.

This object of the present invention will become more apparent from the following description.

The calcium silicate shaped body of the present invention is composed of interconnected spherical secondary particles, each of which is connected in a mutual three-dimensional structure, a thin necked xonotolite having a growth inhibition of crystallite of at least 15 and / Or foshagite (foshagite) crystals, the spherical secondary particles have an outer diameter of about 10 to 80㎛, the apparent density of about 0.13g / cm ³ , a shell shape having a hollow inner space before molding The thickness is about 0.3 to about 10 mu m.

The growth inhibition of the crystallite described above is the inhibition (S) expressed by the following equation.

Where Da, Db and Dc are the magnitudes of the crystallites for xsonotlite or fosgaite in the direction perpendicular to the reflective surfaces 400, 040 and (001), and Da ', Db' and Dc ′ Is β- in the vertical direction with respect to the reflective surfaces 400, 020 and (002) when the xononotrite or fos hagite crystal is converted into β-wollastonite crystals by firing at 1000 ° C. for 3 hours. Represents the dimension of crystallites with respect to wollastonite. The dimension in crystallite size is determined based on the following method. Xonotolite or Phosphite crystals are diffracted by X-rays in the vertical direction of their three planes 400, 040 and (001).

β-walastonite is diffracted by X-rays in the vertical direction of its three planes 400, 020 and (002). Each dimension in the crystaltide size is obtained according to the following equation (Scherrer's equation).

Wherein D is the dimension of the crystallite size.

θ is the diffraction angle.

K is the shape factor as 0.9.

λ is 1.514 kHz, the wavelength of the X-ray (target Cu).

는 반사면의 반 최대선 폭.β

Is half the maximum line width of the reflective surface.

The growth inhibition of crystallites (hereinafter referred to simply as “degree growth” or “inhibition”) will be described in more detail below with respect to xenotelite crystals, for example. Xonaulite crystals are calcined at 100 ° C. for 3 hours and then converted into β-wollastonite crystals, and β-wollastonite crystallites tend to grow larger than the original crystallites of xonotrite. The dimension of the xononotrite crystallite size is determined based on the half maximum line widths of the reflective surfaces 400, 040 and (001), as determined by the X-ray diffraction method. Similarly, the dimension of the crystallite size of β-wallacetonite obtained by calcining xonotolite crystals at 1000 ° C. for 3 hours is determined based on the half maximum line widths of the reflecting surfaces 400, 020, and (002). The degree of inhibition is expressed as the reciprocal of growth, ie, the ratio of the three-dimensional product in the xonotolite crystallite size to the three-dimensional product in the β-wallacetonite crystallite size. If the reverse growth is large, the growth of β-walastonite obtained by calcining xonotolite at 1000 ° C. for 3 hours tends to decrease, and as a result, the β-walllastonite crystal is smaller than that of the original xonotrite crystal. The change in dimension is reduced The present invention provides a unique secondary structure, which will be described below, with at least 15 inverse growth of xonotolite or phosphhagite crystals. And the crystals were achieved in accordance with the finding of a new fact that the crystals form a calcium silicate shaped body with a significant reduction in volume density and improved strength, and a significant improvement in residual strength upon firing at 1000 ° C.

FIG. 1 shows XnOlite with at least 15 inverse growth observed with an electron microscope with a magnification of 30000X prepared in Example 1. FIG. Xononotrite crystals are β-walllaston crystals when calcined at 1000 ° C for 3 hours. When comparing FIG. 1 and FIG. 2, it is hard to find any change in the appearance of the xonotelite crystal before firing and the converted β-walllastonite crystal. Therefore, when viewed under an electron microscope, xonotolite crystals have been found to be fibrous or acicular crystals in which the single crystal has a thin extension and a distinct extinction line with respect to the b axis. 1 and 2 also show that β-walllastonite obtained by heating xsonotrite at 1000 ° C. has the same form as xsonnotrite and has an extension line parallel to the b-axis. It suggests that it happens in part. The crystals in Figs. 1 and 2 are subjected to an extension test in the direction of confirmation by the electron diffraction of the selected portion and the selected portion. On the other hand, FIG. 3 shows Xsonotlite produced in Comparative Example 1 with an inverse growth rate of less than 15 when observed under an electron microscope with a magnification of 30000X. 4 shows crystals obtained by calcining xonotelite crystals at 1000 ° C. for 3 hours. Comparing FIG. 3 and FIG. 4, the growth of the crystal shown in FIG. 4 shows a significant change in the appearance of the crystal. In particular, by heating xsonotlite at 1000 ° C. for 3 hours to β-walllaston, it is easy to remove the intrinsic properties of xonnotrite, and its microscopic transparency decrease and sintering generated by electron beam of increasing crystal thickness It allows them to have a circular tip of the crystals in the state. Comparing FIG. 2 and FIG. 4, the heating reaction which causes the conversion of β-walastonite in the latter case is carried out at the same temperature and for the same time as in the former case, but it is not a simple local reaction but includes destruction and recrystallization. have.

The calcium carbonate shaped body of the present invention is composed of interconnected spherical secondary particles, each of which is formed of thin woody-type xonnotolite and / or phosphhagite crystals which are connected in three dimensions to each other and have a reverse growth rate of at least 15. It is important that it is constructed. Prior to molding, the outer diameter of the spherical secondary particles is about 10 to 80 μm, the apparent density is up to 0.13 g / cm ³ , and about 0.3 to 10 μm thick, preferably about 0.5 to 4.0 μm with a hollow internal space. It is shaped like a shell. First, the structure of the spherical secondary particle before shaping | molding is demonstrated. For example, the spherical secondary particles prepared in Example 1 to be described later are shown in FIG. 5, which was observed by an optical microscope with a magnification of 200X before molding. This photograph shows that the secondary particles of the present invention are spherical and have an outer diameter of 10 to 80 mu m, almost about 20 to 50 mu m.

FIG. 6, which is a scanning electron micrograph showing the same secondary particles at a magnification of 3,000 ×, shows that the thin, flaky xonotelite crystals combine to form a shell with a hollow inner space. FIG. 7 is an electron micrograph showing the same secondary particles at 15,000 × magnification, showing that the shells consist of woody xonotolites tightly bonded in three dimensions. FIG. 8 shows an optical micrograph of a sample of flakes prepared by incorporating the secondary particles into a synthetic resin and cutting the resulting aggregates for a microscope at a magnification of 1,100X. This photograph shows that the thickness of the cuticle of the secondary particles is 0.5 to 4.0 μm. The electron micrograph of FIG. 9 shows that the same sample was magnified at 8,700 ×, and the thickness of the cuticle of the particle was also 0.5 to 4.0 μm, and was composed of densely bound wood-shaped xonotolite particles. When the sample flakes having a thickness of about 3 μm obtained by incorporating the spherical secondary particles of the present invention into the resin and then cutting the resulting aggregates for microscopic examination, the circumference of the particles was obtained from a completely hollow It has been found that it is a completely distinct sphere having a central part and having a thickness of about 0.5 to 4.0 mu m or an average thickness of about 1 earth 3 mu m. The spherical secondary particles of the present invention have a thickness within the range not limited to the above values as in Example 1 but includes 0.5 to 10 μm. For example, Example 3 shows spherical secondary particles having a thickness of 0.5-8.0 μm.

The apparent density of the secondary particles according to the present invention is very light, since it is in the range of 0.06 to 0.13 g / cm ^3, up to about 0.13 g / cm ³ . The apparent density is measured by the following method. The water contained in the slurry of calcium carbonate forming the spherical secondary particles was replaced with acetone, and the resulting aggregates were dried at 105 ° C. for 24 hours to obtain powdery spherical secondary particles without pulverizing the particles. . Wg of this powder is weighed and placed in a beaker. At this time, the water is poured into the burette and the amount of water (Vml) necessary for complete saturation of the particles is measured (ie, when the viscosity of the powder suddenly increases). The apparent density of spherical secondary particles is obtained according to the following equation.

In the above formula, ρx is the abundance of xenonotrite or phosphhagite. Xsonotrite has a specific gravity of 2.79 and Fos Hagite has a specific gravity of 2.63.

The spherical secondary particles of the invention also have the property of having a burning rate of up to about 10% as measured by thermobalance analysis.

The molded article of the present invention is composed of spherical secondary particles bonded together as pressed by a molding process. These spherical secondary particles are gradually deformed and become flat in the pressing direction as the molding pressure increases, that is, as the volume density of the molded body increases. However, when the volume density of the molded body of the present invention is 0.4 g / cm ³ , spherical secondary particles can be confirmed by observing the segmental end of the molded body under a scanning electron microscope. For example, FIG. 10 is a scanning electron micrograph at a magnification of 2,000 × magnification of the segmental end of the molded article of the present invention having a volume density of 0.2 g / cm ³ . This picture clearly shows the splinters of spherical secondary particles. 11 similarly shows the segmental end of the molded article of Example 1 according to the present invention, which has a volume density of about 0.1 g / cm ³ . This picture also clearly shows spherical secondary particles. However, as the volume density of the shaped body increases to 0.4 g / cm ³ or more, the presence of spherical secondary particles is less apparent in the scanning electron micrograph. 14 is a scanning electron micrograph showing the segmental end of the molded article of the present invention having a volume density of 0.4 g / cm ³ or more. It is found that the densely gathered acicular crystal of xonotrite crystals becomes a striped structure in a number of layers with the space part. The layers of the striped structure almost extend in the direction of the extension line (b-axis) of the xonotrite crystal, indicating the selective orientation of the crystal. When using a molded body having a volume density of 0.4 g / cm ³ , hollow spherical secondary crystals pressed and deformed by a molding operation result in a discontinuous stripe array showing a Gneissose structure. When the volume density is more than 0.4 g / cm ³ , the spherical hollow secondary particles overlap the planar layer with the reduced space part due to the use of more continuously oriented crystals in a constant direction according to a special pattern. As shown, Schistose structure with a clear parallel plane. The spherical secondary particles held together by the molding operation, with their adjacent shells in close proximity to each other, impart increased flexural strength of the shaped body to loads acting at right angles to the various layers of the striped structure.

The selectivity degree P has a relationship corresponding to the appearance of the segmented cross section observed under a scanning microscope of at least 600X magnification. More specifically, the microscopic observation shows that a spherical secondary particle having a P of about 5, a swing source structure having a P of about 10, a swing source structure having a larger P value, or a sheath structure and a single structure having a P of about 20 It can be seen that when P is 20, the sheath structure with the segment end perpendicular to the pressing direction is clearly shown. Using a molded body having a volume density of 0.4 g / cm ³ or more, the selective orientation estimated by the X-ray diffraction method of the segmental end of the molded body will indicate that the molded body is composed of a spherical secondary structure according to the present invention. In a plane parallel to the pressing direction of the molded body, no orientation is exhibited regardless of the volume density of the molded body of xononotrite and / or phosphhagite crystals, but the crystal is remarkably in a plane perpendicular to the pressing direction. Oriented. The selectivity degree P is given by the following equation.

x

10의 범위에 있는 값이고, a와 b는 소기의 성형체 내에 함유된 첨가물질에 관계된 계수이다(첨가물질이 사용되지 않을 경우, a는 22, b는 3.8임).Where x is the volume density of the compact

x

It is a value in the range of 10, and a and b are coefficients related to the additives contained in the desired moldings (a is 22 and b is 3.8 when no additives are used).

The selective orientation degree P of the crystal | crystallization which comprises a molded object is measured by the following method. A part of the molded body is collected and subdivided. 1 g of fine particles, 0.2 g of lake-side cement and 5 cc of pentadioxane are thoroughly mixed, and the mixture is heated and stirred at 80 ° C. to evaporate the solvent, and the residue is triturated in mortar to prepare a non-oriented sample powder. Selective orientation degree and P were measured from the molded object, and the other sample which has a specific surface, for example, the surface perpendicular | vertical to a crimping direction, was prepared, and it irradiated by X-ray.

When the shaped body is composed of xonotrite crystals, the diffraction intensities of the two samples are measured on planes 320 and (001). Selective orientation degree P is calculated | required according to the following formula.

Where I 320 and I (001) are the diffraction intensities of the unoriented sample, and I '320 and I' (001) are the diffraction intensities of the sample whose selective orientation is to be measured.

In the case of a molded article made of phosphhagite crystals, the selective orientation is determined by the following equation. However, since the diffraction angles for Phoshagite for (hkO) are not separated separately with overlapping relations for the diffraction angles of the other planes, the sum of the diffraction intensities on planes 220 and 121, i.e., I [ (220) + (121)] and I '[(220) + (121)] are used.

The orientation will be described in detail. As already explained, the orientation refers to a phenomenon in which xonotolite or phosphhagite crystals contained in the molded body are oriented in a constant direction by the molding pressure. This phenomenon is developed by the molded body of the present invention and one of the inventors, and composed of spherical secondary particles which are mutually bonded, as described in the US patent mentioned at the beginning of the present specification, It occurs only in shaped bodies consisting of xenonotrite or phosphhagite crystals. Because the molded body is composed of spherical secondary particles, the influence of the molding pressure applied to the particles changes from some of them to the other part thereof. The spherical secondary particles of the present invention and the particles of the aforementioned patent are almost the same in the density of the cuticles, and the cuticles of the two inventions are given a similar orientation. However, the spherical secondary particles of the aforementioned patents are higher than those of the present invention in apparent density, and as a result, the molded articles of the present invention have a larger number of secondary particles per unit area under the same volume density than that of the aforementioned US patent. Big. Therefore, since the secondary particles of the present invention are further compressed and thus more deformed, there is a difference in the selectivity between the two. In the case of calcium silicate shaped bodies composed of spherical secondary particles that are bonded to each other, the crystals are oriented according to the degree of change due to the difference between the spherical secondary particles constituting the shaped body. Prior to the crystals inside the spherical secondary particles, the crystals in the epidermis are oriented by applying molding pressure. Therefore, the latter crystals tend to be more preferentially oriented.

Comparing the molded article of the present invention and the molded article of the above-described US patent, it can be seen that the former has a feature that the selectivity of orientation is significantly larger than the latter.

Therefore, the use of the molded article of the present invention, when determining the degree of selection orientation, demonstrates that they are composed of spherical secondary particles having the special structure of the present invention. The degree of selective orientation of the molded article of the present invention is defined by the above equation.

The molded article of the present invention is composed of extremely unique xsonotrite or force hagite, which has a reverse growth rate of at least 15 and forms mutually bound spherical secondary particles having the above-described unique structure. Therefore, this molded article has extremely low volume density and high strength, and when fired at 1,000 ° C, the residual strength is remarkably large.

The volume density of the shaped body of the present invention depends on the apparent density of spherical secondary particles forming the shaped body. The smaller the apparent density of the secondary particles and the larger the internal space itself of the secondary particles, the lower the volume density of the resulting molded body. For example, extremely lightweight shaped bodies with a volume density of about 0.06 g / cm ³ can be produced. Furthermore, increasing the molding pressure by the present invention results in a molded article of increased volume density.

The shaped bodies of the present invention may be prepared from a water acidic aqueous slurry containing at least 15 inverse growth and containing spherical secondary particles of wood-like xonotrite and / or phosphhagite crystals bonded three-dimensionally to each other. The tea particles have an outer diameter of about 10 to 80 μm and an apparent density of up to 0.13 g / cm ³ , and are shell-shaped with a hollow inner space and a thickness of about 0.3 to 10 μm. Molded bodies of the present invention with the desired properties that are easily ensured can be made from such water soluble slurries. The moisture present in the secondary particles when forming the slurry can be easily removed between the particles so that the forming pressure can act uniformly through the slurry. Since the moisture inside the particles reacts with the forming pressure, the particles can be pressurized without losing their shape. Internal moisture is a decrease in the amount of moisture in the particles as it moves toward the less moisture. The dehydrated mass thus obtained is dried to obtain a molded article. In this way, the spherical secondary particles in the slurry form a compact without being aggregated. The weight ratio of water to solids of this aqueous slurry is at least 9: 1, preferably about 15: 1 to 30: 1. Since this water-soluble slurry can contain various desired additives, if necessary, the molded article of calcium carbonate of the present invention in which such additives are uniformly mixed can be obtained.

Examples of useful additives include inorganic fibers such as asbestos, rock wool, glass fiber, ceramic fiber, carbon fiber, metal fiber and the like, pulp, rayon, polyacrylonitrile, polypropylene, wood fiber, polyamide, polyester Organic fiber metal wires such as fibers, metal reinforcing materials and the like. According to the present invention, the water-soluble slurry can be formed by a dehydration method using a press, a roll, etc., as well as a casting method, a continuous precipitation method, a centrifugal casting method, a sheet making method, a compression method, and the like.

Generally, water-soluble slurries composed of spherical secondary particles can be prepared according to the following method.

A mixture of lime oil with at least about 45 ml of sediment or mainly crystalline silica is mixed together to obtain a starting slurry having a weight ratio of water to solids of at least 15: 1. There are reinforcing materials including heat agitation at elevated pressures. These additives advantageously impart higher moldability to the product upon molding while at the same time giving the molded body improved mechanical strength, warning properties and other properties. In particular, fibrous materials are good for increasing the mechanical strength of shaped bodies. The thermal insulation can also be improved by various clays. Furthermore, cement, gypsum, clad silica, alumina sol and phosphoric acid or water glass binders may be added to the slurry to reduce or eliminate shrinkage of the molded product upon drying or to impart increased surface strength to the molded product. The present molded product is also subjected to hydrothermal reaction to produce a slurry of spherical secondary particles of xenonotite or phosphhagite according to the present invention. The sedimentation amount is 1.3cm in diameter, 50ml of lime oil in a columnar container having a capacity of at least 50ml, and refers to the capacity of precipitated lime when left to stand for 20 minutes, and lime oil refers to water having a weight ratio of water to solids of 24: 1. And hydrated from lime. If the amount of sedimentation is large, lime in water indicates that the dispersion state is good and stable, that is, it is composed of extremely small particles, and therefore, the reaction phase is high. Accordingly, the present invention is directed to the production of spherical secondary particles having good peeling and low apparent density with the use of lime with good reactivity. The above-mentioned manufacturing method essentially uses lime oil with high dispersion and stability, ie at least 45 ml during the settling period. If the amount of sedimentation of the lime oil is less than 45 ml, the unique spherical secondary particles of the present invention cannot be obtained. As such, lime oil having a sediment amount of at least 45 ml and high dispersibility and stability is a very special lime oil, which has not been used at all in the known method for producing the calcium carbonate mold of the above-described type. However, the method of producing such a special transverse stone itself is of secondary importance and is not subject to any particular limitations. Because lime oil can be used as long as the sedimentation amount is at least 45 ml. The amount of sedimentation of lime oil depends on the limestone used as a starting material, the calcining temperature at the time of lime production, the amount and temperature of the water for watering the lime, and the stirring conditions at the time of stirring. In a conventional lime oil production method, lime oil having a sedimentation amount of at least 45 ml may be prepared.

Lime oil with a sedimentation amount of at least 45 ml is prepared, for example, by stirring water and lime at high speed, preferably at least 60 ° C., with a weight ratio of water to solids of at least 5: 1.

Lime oil can be obtained by vigorous stirring, for example by a homomixer. The speed and intensity of the agitation can be lower if the mixture is shaken for a short time or at high temperature. For example, lime oil hydrated at 20 ° C. can be made into the desired lime oil upon prolonged stirring in a home mixer. Thus, lime oil having a sedimentation amount of 46.5 ml can be prepared from water and quicklime by appropriately stirring to keep the weight ratio of water to solids at least 5: 1 and to prevent precipitation when the mixture is kept at 90 ° C. There are various types of agitators to be used, with and without a protective plate. Various limes such as quicklime are available for making lime oil.

Slaked lime, carbide slag and the like may also be used. Of these, quicklime is most suitable for having increased sedimentation amount.

Useful quartz materials for preparing the aqueous slurry of spherical secondary particles of the present invention include crystalline quartz materials such as quartz rock, quartz, sandstone quartz rock, cement quartz rock, recrystallized quartz rock, hybrid quartz rock, silica sand, and the like. have. These quartzaceous materials used in the present invention generally have an average particle size of up to 50 μm, preferably up to 10 μm. Quartzaceous materials containing amorphous silica are also useful as long as they consist mainly of crystalline quartzaceous materials. It is also possible to use mixtures of less than 50% by weight amorphous silica as crystalline quartz material. Lime and quartzaceous materials are used in proportions necessary for the formation of xonotolite or phosphhagite crystals. The molar ratio of lime and quartz material is preferably 0.85: 1.1, more preferably 0.92: 1.0 for xonotolite crystals, preferably 0.9: 1.5, more preferably 1.1 for phosphhagite crystals. : 1.4. In this case, other calcium silicates may be produced in small amounts. Lime oil and quartz material can be obtained by mixing a weight ratio of water to solids of at least 15: 1 to obtain a raw material slurry. This raw material slurry is stirred and heated under increased pressure for hydrothermal reaction. Reaction conditions, such as a pressure, temperature, and stirring speed, are suitably determined according to the kind of crystal | crystallization of a reactor, a stirrer, and a reaction product. The hydrothermal reaction is usually carried out at a temperature of at least about 175 ° C. and at a minimum pressure of 8 kg / cm ² . Preferred reaction conditions for the production of xonotrite crystals are 191 ° C., 12 kg / cm ^2, and conditions for the production of phosphhagite crystals are 200 ° C., 15 kg / cm ² . The reaction time can be shrunk by increasing the temperature and pressure, the shorter the reaction is economically beneficial. From a safe operation point of view, the preferred reaction time is within 10 hours. The stirring speed for the brine reaction is appropriately determined according to the type of material, the type of reactor and the reaction conditions. For example, the stirring speed is about 100 r.pm when the weight ratio of water to solids in the raw material slurry is 24: 1, and the sedimentation amount is 50 ml, and the fine quartz material having an average particle size of 5 μm is 150 mm in diameter. In a 3-liter reactor equipped with a paddle type stirrer, hydrothermal reaction was carried out under conditions of 191 ° C. and 12 kg / cm ² . In addition, when the weight ratio of water to solids of the raw material slurry is 24: 1 and the sedimentation amount is composed of 47 ml of lime oil, the fine quartz material having an average particle size of 5 µm undergoes hydrothermal reaction under the same conditions as the above conditions, and the stirring speed is about 300 to About 500 r.pm, or about 70 to about 150 r.pm if the reactor is equipped with a shroud. Stirring can be performed by rotating or vibrating the reactor itself, forcing gas or liquid into the reactor, or by stirring. The hydrothermal reaction of the invention can be carried out in a potted or continuous manner. If the reaction is carried out continuously, the raw material slurry is continuously forced into the reactor, while the reacted slurry (ie, the slurry of calcium silicate crystals) is recovered to atmospheric pressure. Care must be taken not to destroy the secondary particles during their recovery. The raw material slurry may also be reacted by lowering the ratio of water to solids so that the final slurry can be treated with a certain amount of water introduced into the reactor after the reaction.

In order to achieve zero calcium silicate crystals, a desired raw material slurry can be obtained by adding a reaction aid (), a catalyst, a precipitation inhibitor, and the like. Examples of such additives include wollastonite, calcium silicate hydrate, alkalis such as caustic soda or caustic and various alkali metal salts.

In order to prepare the slurry of spherical secondary particles according to the present invention, a raw material slurry prepared by adding water, if necessary, from a specific lime oil and quartz material is mixed with inorganic fibers such as asbestos, ceramic fiber, rock wool and the like, resulting. The resulting mixture can be subjected to hydrothermal reaction. This provides a water-soluble slurry in which spherical secondary particles and inorganic fibers according to the present invention are uniformly dispersed in water. There is a difference between the water-soluble slurry obtained by adding inorganic fibers to the water-soluble slurry of spherical secondary particles resulting from the thermal hydrolysis reaction of the water-soluble slurry thus obtained and the raw material slurry. In the former case, the quartz material and the lime material in the raw material slurry crystallize on the inorganic fiber at the same time as the spherical particles tend to adhere to the inorganic fiber and form spherical secondary particles. In the latter slurry, inorganic fibers are added after crystals and spherical secondary particles are formed, so that the inorganic fibers do not bind with spherical secondary particles as a rule. The reason for such a difference is that shaped bodies obtained from the former slurry tend to have slightly higher mechanical strength than those formed from the latter slurry.

The aqueous slurry of spherical secondary particles produced by the above process produces spherical secondary particles according to the present invention upon drying. Since the spherical secondary particles have a unique structure as described previously, that is, they are composed of dense mutually bound xononotrite or phosphhagite crystals and are shell-shaped with hollow inner spaces, The shaped body has a high mechanical strength even though the apparent density of the particles is very low, up to 0.13 g / cm ³ .

According to the present invention, a spherical secondary particle obtained by drying a water-soluble slurry of spherical secondary particles prepared from specific lime oil and quartz material has a characteristic of 10 to 100 mg of initial strain resistance breaking load per particle. As used herein, the term "first star resistance fracture load" means that while secondary spherical particles are subjected to increasing loads, the secondary particles survive their shape against deformation, while cracks At least in part, it refers to the load that occurs within the cuticle (this term will be abbreviated hereinafter as “the initial breaking load”). For example, an initial breaking load of 10 to 100 mg means that the secondary particle cuticle is at a load of 10 to 100 mg. It means at least partially cracking but little deformation. The initial breaking load is measured according to the following method, for example. Three secondary particles of approximately the same particle size were placed on a slide glass in an equilateral triangle array, and the cover glass was placed on the particles, and the particles were inspected by an optical microscope at a magnification of 600X while examining the crack state while applying an increasing load. The load is measured in which the particle causes partial cracking within the cuticle of another particle but does not deform.

The initial breaking load is related to the structure of the secondary particles, in particular the density of the spherical calcium silicate crystals in the epidermis, the outer diameter and apparent density of the particles, and the state of the calcium silicate. The secondary particles according to the present invention, which have high density crystals in which the skin parts are bonded to each other and have a large internal space ratio, have high resistance to deformation and have a limited range of the initial breaking load per particle of 10 to 100 mg. When subjected to a load exceeding this range, the particles are significantly cracked and destroyed. Spherical secondary particles with an initial breaking load of 10 to 100 mg provide a low specific gravity, high sensitivity molded body compared to the previous silicon bone calcium molded body. The shaped bodies of the present invention also exhibit significantly higher residual strength upon firing at 1,000 ° C.

When the present invention is described in detail as an embodiment as follows. In each embodiment, parts means parts by weight unless otherwise specified.

Example 1

Quicklime (42.8 parts, SiO ₂ 0.64%, Al ₂ O ₃ 0.59%, Fe ₂ O ₃ 0.08%, CaO 95.22%, MgO 1.32% burning rate 2.00%) was hydrated at 500 ° C. with 500 parts of water, and the mixture was 30 The lime was dispersed in water by stirring in a homomixer for a minute. At this time, the amount of sedimentation of the obtained lime oil was 50 ml. 45.2 parts of fine powder of quartz (SiO ₂ 98.35%, Al ₂ O ₃ 0.79%, Fe ₂ O ₃ 0.17% burning loss 0.39%) having an average particle size of about 5 μm were added to the lime oil to give a weight ratio of water to solids of 24: 1. A phosphorus raw material slurry was prepared. The slurry was subjected to hydrothermal reaction for 8 hours in a autoclave for 3,000 cc at an internal diameter of 15 cm and a stirrer driving speed of 540 r.pm under a temperature of 191 ° C. and a saturated steam pressure of 12 kg / cm ² .

As a result, as shown in FIG. 12, it was found that the resultant slurry was composed of xonotrite crystals when dried at 110 ° C. for 24 hours and subjected to X-ray diffraction. When measured by X-ray diffraction on the planes 400, 040, and (001), the dimensions of the crystallites of the crystal were D _a = 91 mV, D _b = 450 mV, and D _c = 251 mV. 2θ of planes 400, 040 and (001) were 20.9, 49.6 and 12.7. When the crystal slurry was dried on a slide glass and observed under an optical microscope with a magnification of 200X, it was confirmed that the spherical secondary particles had an average outer diameter of 38 mu m as shown in FIG. Observed by reflected light under an optical microscope, the particles were found to have a clear outline and an almost transparent interior. When the crystal slurry is dried, the dried particles are surrounded by n-butyl methacrylate resin, and the resulting solid aggregate is cut for microscopic examination to produce a sample having a thickness of about 3 μm, and the sample is magnified at 1,100 ×. Was observed with an optical microscope and an optical microscope with a magnification of 8,700X. The results are shown in FIGS. 8 and 9, respectively. It has been found that the cuticle of the particles is in the range of 0.5 to 4.0 mu m, the average thickness is 2.4 mu m, and has a completely hollow interior space. Observation of the secondary particles under an electron microscope of 15,000 × magnification reveals that the cuticle has a myriad of xonotrite crystals projecting from the surface in the form of a beard, as shown in FIG. Observation of the same secondary particles under a scanning electron microscope with a magnification of 3,000X reveals the shape of a spherical epidermis with a hollow interior space, and consists of a myriad of xonotolite crystals bonded three-dimensionally to each other as shown in FIG. have.

Xonotolite crystals (primary particles) forming secondary particles were observed with an electron microscope of 30,000 × magnification, they were about 1 to 20 μm in length, about 0.05 to 1.0 μm in width, and had a sharp outline It is observed that it is a spherical crystal.

Differential thermal analysis of these crystals revealed no peaks, but thermobalance analysis showed a decrease at 750-820 ° C. When these crystals were calcined at 1,000 ° C. for 3 hours and analyzed by X-ray diffraction, β-wallacetonite crystals shown in FIG. 13 were confirmed. The dimensions of the crystallites of these crystals measured at planes 400, 020, and 002 are D _a '= 235 mm, D _b ' = 291 mm and D _c '= 340 mm cross, planes 400, 020 And 2 [theta] of (002) were 23.2, 50.0 and 25.4. These results show an inverse growth rate of 44.2. When observed under an electron microscope, the β-walastonite crystals were in the same form as the xonotelite crystals, and distinct contours were also found.

Table 1 will show the properties of the secondary particles described above.

TABLE 1

The ratio of porosity and internal space of the secondary particles shown in Table 1 is determined by the following equation.

Porosity:

Porosity is calculated by the following formula.

Where ρ is the apparent density of the secondary particles and ρx is the xenotrite specific gravity, ie 2.79 (or 2.63 in the case of Phosphite).

Times of internal space:

The crystal slurry is dried and inserted into n-butyl methacrylate resin, and the resulting cross-section is cut into a microscope to make a sample having a thickness of about 3 mu, and the sample is taken under an optical microscope. The thickness of the cuticle is measured on the photograph and the average thickness, d, of the cuticle is calculated. The ratio of the internal space is calculated by the following equation.

Where r is the average diameter of the secondary particles.

The xonotelite crystal slurry was prevented by placing it in a mould, simultaneously cured and dried to prepare a molded body. Its properties are shown in Table 2.

TABLE 2

Optical micrographs and electron micrographs of the thin end of the molded body are shown to be the same as those of the slurry of secondary particles.

The slurry was press-molded and dried at 120 ° C. for 20 hours to prepare a molded body. Properties of the molded body are shown in Table 3.

TABLE 3

The composition of Table 3 is measured as follows.

Flexural Strength: JIS A 9510

The molded bodies II, III, V and V shown in Table 3 were observed with the scanning electron microscope of 2,000X magnification, respectively, and are shown to FIG. 11, 10, 14, and 15 degree | times. Molded bodies II and III (each volume density is 0.104 and 0.203) have the structure of spherical secondary particles which are bonded to each other, and molded body V (volume density 0.401) is the genesis source structure and molded body V (volume density 0.811) is the cystos structure. Have

Glass fiber (5 parts), 5 parts of cement, and 2 parts of pulp were added to 88 parts (solid content) of the slurry described above. The mixture was press-molded and dried at 120 ° C. for 20 hours to obtain a molded article. The molded body was inserted into the same resin as described above, cut into 3 mm thicknesses, and observed with an optical microscope and an electron microscope. The component particles were found to have the same average particle size and thickness of the cuticle as that of the slurry. It was found by X-ray diffraction analysis that the molded body was composed of xononotrite crystals. Table 4 shows the properties of this molded body.

TABLE 4

The molded body shown in Table 3 was baked at 1,000 degreeC for 3 hours. Table 5 shows the composition of the resulting product.

TABLE 5

The molded article shown in Table 4 was t-stared at 1,000 ° C for 3 hours. Table 6 shows the composition of the product.

TABLE 6

Example 2

The raw material slurry prepared in the same manner as in Example 1 was introduced into a high pressure cooker with a capacity of 3000 cc and an inner diameter of 15 cm, followed by hydrothermal reaction at a temperature of 191 ° C. and a pressure of 12 kg / cm ² for 4 hours while stirring at 540 r.pm. The resulting crystal slurry was dried at 170 ° C. for 24 hours and then its various properties were investigated in the same manner as in Example 1. The dimensions of the xononotrite crystallites were measured at planes 400, 040 and 001, respectively, D _a = 74 ms, D _b = 473 ms and D _c = 255 ms. The crystals were calcined at 1000 ° C. for 3 hours. The resulting β- wollastonite crystallites were analyzed and their dimensions measured at planes 400, 020, and 002, respectively, D _a ′ = 357 μs, D _b ′ = 324 μs and D _c ′, respectively. = 251 kPa. These results show an inverse growth rate of 30.7. Table 7 shows the quality of the secondary particles.

TABLE 7

In the same manner as in Example 1, the crystal slurry was simultaneously cured and dried to obtain a molded product. Its properties are shown in Table 8 below.

TABLE 8

The slurry obtained above was pressurized and dried at 120 degreeC for 20 hours, and the molded object was obtained. The quality of this molded article is shown in Table 9 below.

TABLE 9

The mixture composed of 90 parts (solid content), 2 parts glass fibers, 3 parts cement and 5 parts rock wool obtained by the above method was press-molded to obtain a molded article having a volume density of 0.1. X-ray diffraction analysis shows that this shaped body consists mainly of xenonotrite crystals. Its component secondary particles are the same as the properties shown in Table 7. Table 10 shows the properties of the present molded body.

TABLE 10

The molded body shown in Table 9 was baked at 1000 degreeC for 3 hours. The composition of the resulting product is shown in Table 11.

TABLE 11

The molded body shown in Table 10 was baked at 1000 degreeC for 3 hours. The overall properties of the product are shown in Table 12.

TABLE 12

Example 3

The raw material slurry prepared in the same manner as in Example 1 was subjected to hydrothermal reaction with stirring at 300 r.pm at a capacity of 3000 cc and a high pressure of 15 cm in the background at a temperature of 213.9 ° C. and a saturated steam pressure of 20 kg / cm ² . The resulting crystal slurry was dried at 120 ° C. for 24 hours. When analyzed by X-ray diffraction, the slurry turned out to be xonotolite crystals as a main component.

In the same manner as in Example 1, the dimensions of the crystalline crystallite were measured to find that D _a = 97 ms, D _b = 350 ms and D _c = 170 ms. 2θ of planes 400, 040 and (001) were 20.9, 49.6 and 12.7. The crystals were calcined at 1000 ° C. for 3 hours. The dimensions of the crystallites of β-wallacetonite formed were D _a ′ = 365 μs, D _b ′ = 330 μs and D _c ′ = 250 μs. 2θ of planes 400, 020 and (002) were 23.2, 50.0 and 25.4. The inverse growth rate by these results was 19.2. The composition for the secondary particles was examined in the same manner as in Example 1. The results are shown in Table 13.

TABLE 13

The crystal slurry was simultaneously cured and dried to obtain a molded product in the same manner as in Example 1. Table 14 shows the properties of this molded body.

TABLE 14

The slurry obtained above was press-molded and dried at 110 ° C. for 25 hours to prepare a molded product. The properties thereof are shown in Table 15 below.

TABLE 15

5 parts of asbestos, 3 parts of cement and 2 parts of glass fiber were added to 90 parts (solid content) of the slurry whose main component obtained by the said method consisted of xonotolite crystal | crystallization, and the mixture was press-molded and the molded object was obtained. The secondary particles forming the molded body have the properties shown in Table 13. Table 16 shows the quality of these molded bodies.

TABLE 16

The molded bodies shown in Table 15 were baked at 1000 ° C. for 3 hours. The composition of the product is shown in the following table.

TABLE 17

The molded bodies shown in Table 16 were baked at 1000 ° C. for 3 hours. The composition of the product is shown in the following table.

TABLE 18

Example 4

Quicklime (55 parts, SiO ₂ 0.34%, Al ₂ O ₃ 0.71%, Fe ₂ O ₃ 0.09%, CaO 95.74%, MgO 0.97%, Burning rate 2.23%) using a homomixer for 30 minutes in water 500 The parts were dispersed to obtain a sediment amount of 49 ml of lime oil. A silica sand powder having an average particle size of about 7 μm (45 parts, 99.59% SiO ₂ , 0.16% Al ₂ O ₃ , 0.04% Fe ₂ O ₃ , CaO 0.02%, MgO 0.02%, burning rate 0.13%) was added to the lime oil. It added and obtained the raw material slurry whose weight ratio of water to solid content is 24: 1. The slurry was hydrothermally reacted in an autoclave having a capacity of 3000 cc and an inner diameter of 15 cm for 6 hours at a temperature of 211 ° C. and a pressure of about 19 kg / cm ² with stirring at 540 r.pm. According to the X-ray diffraction, the main component of the resulting slurry was phosphhagite crystals, and contained a very small amount of xanotelite crystals (Fig. 16). When observed under an optical microscope and an electron microscope as in Example 1, the slurry is composed of spherical secondary particles having a diameter of about 20 to about 40 μm, the particles having phosphhagite crystals protruding from the surface thereof. The shell shape was almost similar to that of Phosgaite crystal. FIG. 17 shows the Fosgaite crystals observed with an electron microscope with a magnification of 15000 ×. The secondary particles had an inverse growth of 39.5. The 2θ of the planes 400, 040 and (001) of Phosgaite were 36.9, 49.7 and 13.1, and that of β-walastonite was 23.2, 50.0 and 25.401. Table 19 shows the other properties of the secondary particles.

TABLE 19

The molded article having a density of 0.071 (g / cm ³ ) was prepared by pouring the above-mentioned phosphhagite crystal slurry into a mold and simultaneously curing and drying.

7 parts of asbestos, 1 part of glass fibers, and 1.5 parts of potland cement were added to a part of the slurry (solid content of 90.5 parts), and the components were mixed with each other, followed by molding by pressing and dehydrating. The molded mass was dried to obtain a molded article III. Molded article IV was prepared in the same manner as above. However, pressure stage was changed at the time of pressurization. Molding bodies I and II were also produced only as slurry. Molded article V was further produced in the same manner as molded article III. However, the potent cement was replaced with 0.2 parts of colloidal silica in a solution state (solid content 20%). Molded bodies VI and V were also prepared from 90 parts of slurry (solid content), 8 parts of glass fibers (formed body VI) and 2 parts of pulp (formed body X). The composition properties of these molded bodies are shown in Table 20.

TABLE 20

Example 5

1,2,5,10 and 15 parts (solid content) of polyacrylic acid ester resin dispersion (trade name Mowinyl-742, Japanese Chast Kosei Cuppeny, Limited) in 100 parts (solid content) of the xonotolite crystal slurry obtained in Example 1 ) Were added, and each mixture was placed in a wired mold, followed by compression dehydration for molding. Each molded article was dried at 170 ° D. for 10 hours to prepare a molded article. Table 21 shows the properties of these shaped bodies.

TABLE 21

Example 6

To 100 parts (solids) of xsonotolite crystal slurry obtained in Example 1, 5 parts (solids) of the same emulsion as in Example 5 and a certain amount of pulp were added. Each resultant mixture was placed in a wire mesh mold and then molded by pressure dehydration. Each molded article was dried at 170 ° C. for 10 hours to obtain molded articles I, II, and III, which are shown in Table 22 below.

Table 22

Example 7

To 100 parts (solids) of xsonotolite crystal slurry obtained in Example 1, 5 parts (solids) of the same emulsion as in Example 5, 10 parts of glass fibers and a certain amount of pulp were added. Each mixture was poured into a wired mold and molded by compression dehydration. Each molded article was molded at 170 ° C. for 10 hours to produce a molded article. Each property of these molded objects is shown in Table 23 below.

TABLE 23

Example 8

Quicklime (42.3 parts) was hydrated with water 15 times the amount of quicklime at 60-65 ° C. and dispersed in a homomixer for 30 minutes to obtain 46.0 ml of lime oil. 45.2 parts of the silica sand powder (SiO ₂ 98.04%, Al ₂ O ₃ 0.67%, Fe ₂ O ₃ 0.04%, CaO 0.02%, MgO 0.02, burning rate 0.13%) was added and the weight ratio of water to solids was 18: 1. A raw material slurry was obtained. The slurry was subjected to hydrothermal reaction for 8 hours in the same autoclave as in Example 1 equipped with a suitable protective plate while stirring at a temperature of 191 ° C. and a pressure of 12 kg / cm ² at 140 r.pm. X-ray diffraction analysis showed that the slurry consisted of xonotrite crystals.

The inverse growth rate of these decisions is 35.1. Table 24 shows the properties of the spherical secondary particles of the slurry.

TABLE 24

This crystal slurry was press-molded and dried at 120 degreeC for 20 hours, and molded objects A, B, and C were obtained. Furthermore, the mixture of this slurry (90 parts of solid content) and 10 parts of the same emulsions in Example 5 was dried, and molded bodies D, E, and F were obtained. The following table shows each property of these molded objects.

TABLE 25

Comparative Example 1

The same quicklime (41.5 parts) as in Example 1 was hydrated at 500 ° C. with 500 parts of water to obtain a lime oil having a sediment amount of 41 ml. Aqueous dispersion prepared by stirring 4 minutes of fine silica powder (amorphous silica 93.20%, Al ₂ O ₃ 0.018%, Fe ₂ O 0.78%, CaO 0.12%, MgO 3.29%, burning rate 1.68%) and stirring in a homomixer for 20 minutes Was added to lime oil to obtain a raw material slurry having a weight ratio of water to solids of 24: 1. The slurry was hydrothermally reacted for 8 hours in an autoclave while stirring at 1000 r.pm at a temperature of 191 ° C. and a pressure of 12 kg / cm ² to obtain a slurry of xenonotrite crystals. The dimensions of the crystallites of the crystals measured in the planes 400, 20 and 001 were D _a 321 kV, D _b 380 kV and D _c 197 kV, respectively. The dimensions of the crystallites of β-wallacetonite prepared by firing at 01000 ° C. for 3 hours were measured at planes 400, 020, and 002, and D _a '191', D _b '743' and D _c ' 722 Å. These results show a reverse growth rate of 2.3.

The properties of the secondary particles described above are shown in Table 26.

TABLE 26

The slurry obtained above was press-molded, and it dried at 120 degreeC for 20 hours, and obtained molded objects I, II, and III. The mixture of 90 parts of the slurry (silica) and 10 parts of the cement was subjected to abrasion molding, and dried at 120 ° C. for 20 hours to prepare molded articles IV, V, and VI. Table 27 shows the properties of the molded body thus obtained.

TABLE 27

The molded body shown in Table 27 was baked at 1,000 degreeC for 3 hours. Table 28 shows each property of the product.

TABLE 28

Comparative Example 2

The same quicklime (42.3 parts) as in Example 1 was hydrated with 50 parts of water at 90 ° C to 95 ° C to obtain a lime oil having a sediment amount of 41 ml. 45.2 parts of quartz rock as in Example 1 were added to this lime oil to obtain a raw material slurry having a weight ratio of water to solids of 24: 1. The sludge was subjected to hydrothermal reaction for 10 hours in an autoclave while stirring at a temperature of 191 ° C. and a pressure of 12 kg / cm ² at 100 r.pm. X-ray diffraction indicated that the resulting slurry was composed of xenonotrite crystals. The dimensions of this xonotolite crystallite particle size were D _a = 360 mm 3, D _b = 338 mm 3 and D _c = 165 mm 3. When this crystal was calcined at 1,000 ° C. for 3 hours, the resulting crystallite grain size was D _a ′ = 3602, D _b ′ = 304 kHz, and D _c ′ = 271 Å, respectively. According to these results, the inverse growth rate S is 40.5. Table 29 shows the properties of the spherical secondary particles of xantholite crystals.

TABLE 29

The slurry obtained above was press-molded and obtained molded objects I, II, and III. Further, the mixture composed of the slurry (90 parts of solid content) and 2 parts of Asbestos 5 parts of cement and 3 parts of clay was molded beforehand to obtain moldings IV and V. FIG. Table 30 shows each property of these molded bodies.

TABLE 30

The molded bodies shown in Table 30 were calcined at 1,000 ° C. for 3 hours. Table 31 shows each property of the resulting product.

Table 31

Claims (1)

Lime oil, crystalline silicon acid raw material and water with a sedimentation amount of 45 ml or more are mixed so that the amount of water to solid content in the slurry obtained is at least 9 weight times or more to prepare a raw material slurry, and the raw material slurry obtained is pressurized and heated under stirring to obtain hydrothermal ( Manufacture of calcium silicate molded body characterized by the steps of obtaining a slurry of zonotlite or foshagite crystals by synthesizing water, forming the slurry, and drying the molded product. Way.

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