JPS60155560A - Forming material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a molding material containing secondary particles of a silica-calcium carbonate composite as a constituent component.

Silica gel is conventionally known as a typical example of amorphous silica, and is mainly produced by neutralizing an aqueous sodium silicate solution with an acid such as hydrochloric acid or sulfuric acid, precipitating a precipitate, washing with water and drying. If necessary, it is further activated by heating under reduced pressure. Further, the silica gel is obtained in a cine-shaped or spherical shape according to the manufacturing method, and is shaped into a tablet or the like using a binder or the like if necessary. Its uses include, for example, as a desiccant, an adsorbent, a dehydrating agent, a deodorizing agent, and a catalyst carrier because of its hygroscopicity and large specific surface area.

However, silica gel has the property of rapidly absorbing water and disintegrating when it comes into contact with water, making it impossible or difficult to use it in a system where it is directly in contact with water. In general, silica gel is 20~
It has an average pore diameter of 220 A, but those with a small average pore diameter usually have a bulk density of around 0.7 f/cr/1, whereas those with a bulk density of around 0.2 f/cd have an average pore diameter of around 0.7 f/cr/1. is inevitably large, usually 180 to 22
It will be about 0A. Therefore, silica gel having an average pore diameter of about 20 to 40 λ, which is suitable as an adsorbent for gases, water, etc., has a large bulk density, and its adsorption capacity per unit weight is naturally limited. In addition, Japanese dogs have a low bulk density and a large specific surface area, but those with a large specific surface area also have a large bulk density and are inevitably lacking or insufficient in oil absorbing ability. Furthermore, silica gel cannot be used as a raw material for fireproof and heat-resistant materials such as heat-resistant glass.

Calcium carbonate is usually produced by mechanically crushing seashells, chalk, refined limestone, etc., or by adding water to quicklime to make lime milk, and then reacting it with carbonate, and it is available from relatively inexpensive sources. In the form of fine particles, it is used for a wide range of purposes, including the same uses as the above-mentioned silica gel, as a raw material for methacrylic acid, as a raw material for various chemicals, and for neutralization.

Problems to be Solved by the Invention The present invention is made by dispersing in water a composite consisting of a new crystal-like amorphous silica in appearance, which replaces the above-mentioned known silica gel, and ultrafine calcium carbonate attached to the silica. The object of the present invention is to provide a novel molding material that can be molded without using any binder or the like, thereby producing a lightweight and strong molded product.

Means for Solving the Problems According to the present invention, it has at least two surfaces in a symmetrical relationship, has a length of about 1 to 500μ and a thickness of about 50A to about 1μ, and the length is equal to the thickness. A molding material is provided in which secondary particles of a silica-calcium carbonate composite composed of amorphous silica having a crystal-like appearance and ultrafine calcium carbonate attached to the silica are dispersed in water.

In this specification, the silica-calcium carbonate composite secondary particles constituting the molding material of the present invention will be referred to as "Silsite I".
It is called. In addition, the primary particles of amorphous silica that are crystal-like in appearance, which are the two components constituting silsite (■), are called "opsil (■)".

Silsite I consists of Odusil I and ultrafine calcium carbonate attached to it. Opsile I has at least two symmetrical faces, a length of about 1 to 500μ, a thickness of about 50λ to about 1μ, and a length of at least 10μ of the thickness.
It has a size that is twice as large. As a result of X-ray diffraction analysis, it is amorphous with no diffraction peaks, and chemical analysis after ignited dehydration shows that the SiO2 content exceeds 98% by weight, and electron microscopy shows that it is amorphous. It is characterized by having at least two symmetrical faces and a crystal-like appearance.

It is attached in a way that it cannot be separated. For example, silcite ■ is dispersed in water at a concentration of 5% by weight, stirred for 20 minutes, and then left to stand.
) and calcium carbonate are not separated at all by sedimentation due to the difference in their specific gravity, and it is recognized that both are stuck together due to chemical or physical forces.

The fact that Silsite I is an amorphous silica-calcium carbonate complex is confirmed by X-ray diffraction analysis, which shows that the diffraction peaks (2θ) peculiar to calcium carbonate are 23.0', 29.4°, and 3.
6.0° or 23.0.24.8, 27.0.29.
4°, 32.8°, and 36.0°, chemical analysis after ignited dehydration showed that the main components were SiO2 and CaO, and electron microscopy showed that Odusil I had a crystal-like appearance. This is confirmed by the fact that it is composed of fine particles.

The unique appearance of silica I, which constitutes silcite (2), is brought about by the fact that it is derived from silicate crystals and is converted into amorphous silica with the remains of the crystals remaining.

Therefore, opsil (1) has substantially the same external shape and size as the silicate crystal that is the original crystal. For example, Opsil I derived from a rectangular calcium silicate crystal such as wollastonite, linotrite, and phoshadate has a rectangular outer shape. Ozil (2) derived from plate-shaped calcium silicate crystals such as tobermolite, gyrolite, and α-tied calcium silicate hydrate (α-C2SH) has a plate-like external shape. Opsile I, which has the shape of a rectangular strip, a plate, etc., has a length of about 1 to 500 μ, a thickness of about 50 A to 1 μ, and the length is at least 10 times the thickness. The rectangular optic I derived from the linotrite crystal retains the crystal habit of the crystal and typically has a length of 1 to 50 μm, about 100 μm.
The length is about 10 to 5000 times the thickness. The plate-shaped Saizusil I derived from the Tobel heptalite crystal retains the crystal habit of the crystal and has a length of about 1 to 50 μm and a length of about 100.4 to 0.5 μm.
It has a thickness of about 0.2 to 20 μm, and a length of about 10 to 5000 times the thickness.

The rectangular shape derived from wollastonite crystal retains the crystal habit of the crystal, has a width of about 1 to 500 microns, and has a length of about 10 to 5,000 times the thickness. The plate-shaped Odushiru ■ derived from the gyrolite crystal retains the crystal habit of the crystal and has a length of about 1 to 50 μm and a length of about 100 A to 0.5 μm.
It has a thickness of about 1 to 20 μ and a length of about 10 μ of the thickness.
~5000 times. The plate-shaped Saizusil I derived from α-tai calcium silicate hydrate crystal retains the crystal habit, has a length of about 1 to 300 μm, and has a diameter of about 500 A.
It has a thickness of -1μ and a width of about 1 to 50μ, and its length is 10 to 5000 times the thickness.

The chemical composition of Saizusil I after ignited dehydration (Ig, 1oss about 4-7% by weight) is as follows, and the physical properties are as shown in Table 1 below in comparison with silica gel.

Chemical composition (wt%) of Ozusil■ SiO2>98.0 AI3203 (1,□ Fe2O3<O-01 CaO (0,02 Table 1 However, RD1 in Table 1) Hashiko Yuladun City, ID2
) indicates Isitermediate Decisity, LD3) indicates 0-decisity, Encyclopedia of C
Chemical Technology) Volume 18 1
969, p. 61-67. Further, each physical property in Table 1 was measured by the following method.

Bulk density: 50f/cr! The cross-sectional area of 10f of powder is 5c using the load histo-silicon method! ! After putting it in a cylinder and applying a load of 25 to it, its volume is calculated using the following formula.

True specific gravity: According to Betsukumashi air comparison type hydrometer, H
Find e-katana susu replacement.

Average pore diameter: Based on BET nitrogen adsorption method.

Specific surface area: Based on BET nitrogen adsorption method.

Pore volume: Based on BET nitrogen adsorption method.

Particle diameter: Based on optical microscope/electron microscope.

Oil absorption: indicates the amount of oil when octyl phthalate (C6H4(COOC8H□7)2) is dropped into 1002 powder and absorbed, and viscosity suddenly appears.

Hygroscopicity: Place the powder in a container with relative humidity of 100%.
The adsorption was maintained at 5° C. until an equilibrium state was reached, and the adsorption is expressed in weight %.

However, each numerical value in the table is a bulk density of 0.1r/m for Saizusil, a bulk density of 0.7f#d for RD, a bulk density of 0.4t/crIl for ID, and a bulk density of 0-1 for LD.
This is data when using 5 f /cr/l, respectively.

As is clear from Table 1 above, although Saizusil I has a small bulk density, it is suitable for adsorption of gas and water.
It has a small average pore diameter of about 0 to 40 A, and a large specific surface area, and exhibits excellent adsorption ability for gases, water, etc., as well as excellent oil absorption ability. Furthermore, Odushiru (3) has excellent water resistance and does not disintegrate at all even when immersed in water, so it can be used very advantageously even in systems where it is directly mixed with water. Further, Ozil I has a property of having low thermal conductivity and can be sintered at temperatures up to loO'o°C. In addition, p near neutrality of 6 to 7
It has excellent chemical resistance and is not decomposed by acids such as hydrochloric acid. These properties are advantageous compared to the fact that the original calcium silicate crystal has a high pH of 10 to 11 and is subject to decomposition by acids such as hydrochloric acid, which limits its use.

This is because the silcite (constituting the molding material of the present invention) is composed of opsilite (2), which has the above-mentioned unique particle shape and characteristics, and ultrafine calcium carbonate that is physically or chemically attached to the opsilite (2). , can be molded in the form of an aqueous slurry without using any visitors, etc., and has unique properties that allow the production of lightweight and strong molded products, and the molded products obtained by molding this are unique. Sill I
By taking advantage of the properties of calcium carbonate, it can be used as an alternative to applications for which silica gel has traditionally been used, and it can also be used in applications where silica gel cannot be used, and by utilizing the properties of calcium carbonate, it can be used for applications where calcium carbonate has been used. can also be used as an alternative. Typical examples include various fillers, desiccants, adsorbents, deodorants, filtration agents, additives for adhesives, heat resistant agents, matting agents for paper manufacturing, emulsifiers for cosmetics, anti-wear agents, heat insulating agents, thickeners, Pigments, toothpaste, agricultural carriers, pharmaceutical carriers, catalysts, catalyst carriers, fillers for gas chromatography, excipients, anti-caking agents, volatile substance fixatives, seven-year-old sheep, heat-resistant glass raw materials, etc. Useful for applications. It is particularly useful as a heat-resistant material, a heat-retaining material, a filtration material, a catalyst carrier, etc.

In order to obtain the above-mentioned molded article, the molding material of the present invention is preferably in the form of an aqueous slurry having a water-to-solids ratio (weight) of 4 to 50:1. In addition, the slurry may contain fibrous reinforcing agents such as asbestos, glass fiber, ceramic fiber, rock wool, synthetic fiber, natural fiber, pulp, carbon fiber, metal fiber, and styless fiber, aluminalyl, co-ital silica, etc., as necessary. Various additives such as clays, clays, cements, colorants, fillers, etc. can be added, thereby imparting further useful properties. The molded product obtained usually has a thickness of 0.1 to 0.4 f.
It has a high bending strength of about 3 to 30 to 9/i with a low bulk density of about /m. It is also possible to increase the above-mentioned bulk density, and a molded article having greater mechanical strength in proportion to the bulk density can be obtained. For example 0.4 f
/cd -1,0t/cd for a molded body with a bulk density of 20
~100Kp/CI! It has a certain degree of bending strength.

The reason why the above-mentioned molded product is so lightweight and has excellent mechanical strength is that the particles of silcite (2) are firmly bonded to each other and have a large porosity. This porosity increases as the density decreases.

The silcite ■ constituting the aqueous slurry of the present invention is 5 inches
It can be made from a variety of natural or synthetic silicate crystals with a tetrahedral steel-like or chain-like structure. The method for producing it is not particularly limited and any method can be adopted, but it is most advantageously produced as follows using calcium silicate crystals as a raw material. That is, it is produced by bringing calcium silicate crystals into contact with carbon dioxide gas in the presence of moisture.

The greatest feature of this production method is that calcium silicate, which constitutes the calcium silicate crystal, can be converted into amorphous silica and calcium carbonate without substantially changing the external shape of the calcium silicate crystal.

Calcium silicate crystals, which are the origin crystals, include wollastonite, linotrite, huoshagite, finzu,
Wollastonite calcium silicate crystals such as 7-tite and O-zessihanite, tobel-septite calcium silicate crystals such as tobermolite, gyrolite-based calcium silicate crystals such as gyrolite, trascotite, and lierite, calciocoside O-tite, + R-4 calcium silicate-based calcium silicate crystals such as lucoanite and aphdoillite, α-tai calcium silicate hydrate, and the like are included. Odo crystals are used as the source material in the form of primary particles, and the outer shape of the crystal is not impaired and the silsite I to oscillate that constitutes it are essentially intact.
inherited.

That is, primary particles of calcium silicate crystals (having at least two symmetrical faces, a length of 1 to 500 μm and a diameter of 50 μm
λ~1μ in thickness, and the length is at least 10 times the thickness), silcite ■, that is, sillsite I, which has the remains of the above-mentioned crystal grains as it is, exists attached to it. Calcium carbonate is obtained.

The above-mentioned calcium silicate crystalline particles used for producing Silsite I can be prepared by a known method, for example, Japanese Patent Publication No. 45-2.
No. 5771, Special Publication No. 30-4040, Special Publication No. 41
By crushing spherical shell-like secondary particles or molded bodies of calcium silicate crystals obtained by the methods described in Publication No. 1953, US Patent No. 2,699,097, US Patent No. 2,665,996, etc. Easy to manufacture.

The silicic acid raw materials for obtaining the above calcium silicate crystals are as follows:
Various materials containing silicic acid as a main component, such as natural amorphous silicic acid, silica sand, diatomaceous earth, clay, slurry, clay, fly ash, perlite, white carposi, and silicoshitast, can be used alone or in combination of two or more. As raw materials for lime, for example, quicklime, slaked lime, carbide residue, cementite, etc. can be used singly or in combination.
Can be used by mixing more than one species. Each of these families is usually CaO
It is best to mix so that the molar ratio of :5g02 is in the range of 0.5 to 3.5 :1.
Additives such as reinforcing agents such as TiOnia, vinylOnia, natural fibers, pulp, fibers, carbon fibers, and colorants may be blended. Further, in the above, the amount of water can be varied over a wide range, and is generally preferably about 3.5 to 25 times the total weight of solids. The reaction temperature is the saturation temperature of water vapor pressure, and the reaction is usually completed in about 0.5 to 20 hours. Calcium silicate crystals having various degrees of crystallinity can be obtained depending on the molar ratio of CaO: 5in2, reaction pressure, temperature, time, etc. The calcium silicate crystals include various crystal systems such as nonodorite, tobermolite, and phosagite. ; Yai 0 light, α-Thai calcium silicate hydrate, etc.

Furthermore, by further firing the above-mentioned linotrite crystals at about 1000°C, the crystals constituting the linotrite crystals can be made into wollastonite without changing its shape (Japanese Patent Publication No. 50-29493).

Silsite (2) can be obtained by forcibly carbonating calcium silicate crystals in the form of primary particles obtained as described above by bringing them into contact with carbon dioxide scum in the presence of water.

The carbonation is performed by introducing carbon dioxide gas into the reaction system and bringing the crystals into contact with the carbon dioxide gas in the presence of water.
It is done well.

This can be done, for example, by placing calcium silicate crystals in a suitable airtight container and introducing carbon dioxide gas under high humidity or a humid atmosphere, or by immersing calcium silicate crystals in water or carbonated water and then introducing carbon dioxide gas. It can be implemented easily. This carbonation proceeds sufficiently at room temperature and pressure as long as carbon dioxide gas is introduced into the system, but preferably under pressure (10Kp).
/cr! It is preferable to carry out the reaction under a pressure of about 100 to 100 ml (under gauge pressure), thereby increasing the rate of carbonation and making it possible to complete the reaction in a short period of time. The amount of carbonate sludge used is stoichiometric or more. When carbonating silicon-calcium crystals by immersing them in water, the carbonation rate can also be accelerated by stirring the reaction system. The ratio of water to calcium silicate crystals used is usually 1 to 50:1, preferably 1 to 25:1. (weight ratio). The rate of carbonation varies somewhat depending on the crystallinity of the calcium silicate constituting the raw material, but for example, when carbonating nonodorite crystals, the rate of carbonation is recognized to be the slowest.
By setting the amount of water added to be about 2 to 6 times the dry weight, the reaction can be completed in about 10 hours. In addition, the amount of water added was increased by 5 times, and the reaction system was increased to 2 to 4/CI! (gauge pressure), the reaction is usually completed in around 1 hour, and if this pressurization condition is 3Ky/cIIt (gauge pressure), then
It is recognized that the reaction is completed in an extremely short time of about 0 minutes.

The carbonation reaction proceeds as shown in the following reaction formula depending on the type and crystallinity of calcium silicate crystals used as raw materials.

xCaO-8iO-mHO+CO2 22 →CaCO3+SiO2・n, H2O However, in the above formula, X is 0.5 to 3.5.

The calcium silicate crystals described above are converted into amorphous silica and ultrafine crystals of calcium carbonate without substantially changing the external shape of the particles and thus without any morphological change. In other words, the chain structure of SiO4 tetrahedra that forms the skeleton structure of the calcium silicate crystal is maintained as it is, and due to this chain structure, amorphous silica with a crystalline appearance (extremely fine calcium carbonate adhering to the optic silica) is formed. It is attached in such a way that it cannot be easily separated.

EXAMPLES Reference examples and examples are given below to explain the present invention in more detail.

The X-ray diffraction diagram, electron micrograph, and pore size distribution diagram of the substances obtained in each Reference Example and Example are shown in the drawings.

FIGS. 1(8) and 1(b) are X-ray diffraction patterns of the starting materials, nonodrite crystal and silsite I, respectively.

This is done using an X-ray diffractometer with a Cu target at a wavelength of 1,
It was recorded by generating 5418 AOX rays, irradiating the sample with them, and calculating the diffraction angle and diffraction intensity.

Figures 2 and 3 are electron micrographs at a magnification of 20,000 times. In each figure, (8) is a photograph of calcium silicate crystals, which are the starting material, and (g) is a photograph of Silsite I obtained therefrom.

Figure 4 is a 5000x electron micrograph, (9) in the figure.
(g) is a photograph of α-tai calcium silicate crystal, which is a starting material, and (g) is a photograph of Silsite I obtained from the crystal.

Figure 5 is a pore size distribution diagram of Silsite (XIO)
shows.

Reference Example 1 Quicklime is used as a lime raw material and 350 mesh silica powder is used as a silicic acid raw material. These and the like are dispersed in water at a molar ratio of lime to silicic acid of 0.98:1 to prepare a raw material slurry at a water to solid content ratio (weight) of 12:1.

The raw material slurry is charged into an autoclave, heated to 191° C., and subjected to a hydrothermal reaction under a saturated steam pressure of 12 kg/crl for 8 hours with stirring to obtain a slurry of linotrite crystals.

The X-ray diffraction diagram of the obtained crystal is as shown in Figure 1 (2), showing diffraction peaks (2θ) characteristic of linotrite crystals at 12.7°, 27.6°, and 29.0°. . Its composition after ignition is as follows.

5iO248,88chi CaO45,60 AI32030,26 Ftt2030-54 1g, 1oss 4.51 99.79 Next, the above slurry is dried at 150°C and pulverized to obtain a white fine powder. The electron micrograph is shown in FIG. 2 (8). From the figure, the above-mentioned secondary particles have at least two symmetrical surfaces, a length of about 1 to 20 μm, and a thickness of about 0.02 μm.
~0. It can be seen that it has a size of iμ and a width of about 0.02 to 1.0μ, and the length is at least about 10 times the thickness.

The secondary particles have a specific surface area of approximately 50 TrL'/l.

Reference Example 2 Slaked lime is used as a lime raw material and 350 mesh silica powder is used as a silicic acid raw material. These and the like are dispersed in water at a molar ratio of lime to silicic acid of 0.80:1, and a raw material slurry is prepared by setting the water to solid content ratio (weight f!k) to 12=1. The raw material slurry was charged into an autoclay and heated to 191°C.
The mixture was heated to 12 Kf/crl and subjected to a hydrothermal reaction with stirring for 5 hours under a saturated steam pressure of 12 Kf/crl to obtain a slurry of tobel heptalite crystals.

The result of X-ray diffraction analysis of the obtained crystal was 7.8°, 29.
It shows diffraction peaks (2θ) characteristic of tobermolite crystals at 0° and 30.0°. Its composition after ignition is as follows.

Sx 0248-38% CaO3B, 55 AI32030.31 Fe203 00-4 5I・1oss 11-36 99.05 Next, the slurry was dried at 150°C and then ground.

A fine white powder is obtained. The electron micrograph is shown in Figure 3 (8
) is shown. As shown in the figure, the above-mentioned secondary particles have at least two symmetrical surfaces and have a length of about l to 20μ, a thickness of about 0.02 to 0.1μ, and a width of about 0.2 to 5.0μ. It can be seen that the length is at least about 10 times the thickness. The secondary particles have a specific surface area of about 61 m'/f.

Reference Example 3 Quicklime is used as a lime raw material and commercially available white carposi (particle size 100 mμ or less, St 02 content about 88% by weight) is used as a silicic acid raw material. These and the like are dispersed in water at a molar ratio of lime to silicic acid of 0.57:I to prepare a raw material slurry with a water to solid content ratio (weight) of 1221. The raw material slurry is charged into an autoclay, heated to 200° C., and subjected to a hydrothermal reaction with stirring under a saturated steam pressure of 15 kg/d for 8 hours to obtain a slurry of gyrolite crystals.

The result of X-ray diffraction analysis of the obtained crystal was 4.0°, 28.
At 2° and 28.9°, diffraction peaks (2θ) characteristic of Ceyrolite crystals are shown. Its composition after ignition is as follows.

St O256-88% CaO30,75 AI32030, 39 pe2o3 0.29 1 g-1 oss] 1.39 99.70 Then, the above slurry is dried at 150°C and then ground to obtain a white fine powder. As a result of electron microscopy, the obtained primary particles have at least two symmetrical surfaces and a length of about 1 to 1.
20μ, thickness approximately 0. , 02~0.1μ and width about 0.2~
It can be seen that it has a size of 5μ and the length is at least 10 times the thickness.

The particle size is approximately 60 m'/? It has a specific surface area of

Reference Example 4 Quicklime is used as a lime raw material and 350 mesh silica powder is used as a silicic acid raw material. A raw material slurry is prepared by dispersing these in water at a molar ratio of lime to silicic acid of 2.0:1, and setting the water to solids ratio (weight) to 4:1.

The raw material slurry is charged into an autoclave, heated to 191'C, and reacted under a saturated steam pressure of 12 kg/ci for 5 hours to obtain a slurry of α-tai calcium silicate hydrate crystals.

As a result of X-ray diffraction analysis, the obtained crystal has an angle of 16.6°, 27
．． Diffraction peaks (2θ) characteristic of α-tai calcium silicate hydrate crystals are shown at 3° and 37.2°. Its composition after ignition is as follows.

5iO230, 81% CaO57, 02 μg2030, 45 Fe2030, 50 μg, 1oss 10.05 98.83 The slurry obtained above was dried at 150°C and then ground to obtain white fine powder-secondary particles. The electron micrograph is shown in Figure 4 (8).
). As shown in the figure, the above-mentioned particle has at least two symmetrical surfaces, a length of about 1 to 300 μm, and a thickness of about 0.
．． It can be seen that it has a plate-like form with a size of 1 to 1μ and a width of about 1 to 30μ, and the length is at least 10 times the thickness. The particle size is about 6. It has a specific surface area of ziy.

Example ! The nonodrite needle-like crystal particles obtained in Reference Example 1 are used as a starting material. This was placed in a closed pressure vessel together with 5 times its weight of water, and carbon dioxide gas was pressurized into the vessel at room temperature to raise the internal pressure to 3Kq/cr! Carbonation is carried out for about 30 minutes.

In this way, amorphous silica-calcium carbonate composite particles (Silsite ■) are obtained.

The results of the analysis are as follows.

Composition (H) Ss 0236.04 CaO33-54 M2030.18 Fe2030.38 1, q, 1oss 28.87 Total 99-01 The X-ray diffraction results are shown in Figure 1 (G). All the peaks peculiar to calcium silicate crystals observed in Figure 1 (6) have disappeared and the angles are 23.0° and 29.0°.
Only the diffraction peaks (2θ) of calcium carbonate crystals appeared at 4° and 36.0°, indicating that calcium silicate was converted into amorphous silica and calcium carbonate by carbonation.

Furthermore, the results of electron microscopic observation are shown in Figure 2 (to).

As shown in the figure, the composite particle has at least two symmetrical faces, a length of about 1 to 20 μm, and a length of about 0.02 to 0.0 μm.
Amorphous silica having a thickness of 1μ, a width of about 0.02 to 1.0μ, and a length of at least 10 times the thickness, in the form of ultrafine particles of about 2μ or less. It can be seen that calcium carbonate fine particles are attached. The shape of the amorphous silica is exactly the same as that of the linotrite needle crystals used as the starting material (Figure 2 (6)), and it can be seen that the linotrite acicular external shape is maintained as it is. .

This composite particle was prepared by dispersing it in water to a concentration of 5% by weight.
After stirring for 0 minutes and leaving to stand, the silica and calcium carbonate constituting the particles cannot be separated at all even if they are tried to separate by sedimentation due to the difference in specific gravity, and the two are firmly attached chemically or physically. is recognized.

The characteristics of Silsite I obtained above are shown below.

Bulk density: 0.139 y / specific surface area: 63 cm / oil absorption fit: 300 cc / 100 r Furthermore, the state of the pore size distribution of Silsite I is as shown in curve (1) in Figure 5, with its peak at 27A. is recognized.

The aqueous slurry of the present invention is obtained by dispersing the above-obtained silcytoe in water such that the weight ratio of water to solids is 5:I.

Next, the obtained aqueous slurry is placed in a mold, dehydrated, molded, and dried to obtain a molded body. The physical properties of the obtained molded article are shown below.

Bulk density 0.37ri/6! Porosity: 84.8% Heat resistance at 950℃ No change Compressive strength: 12 Kylcr & Bending strength: 8 chest/cI! Example 2 The tobermolite plate-like crystal-order particles obtained in Reference Example 2 were used as a starting material. This is placed in a closed pressure vessel together with 5 times its weight of water, carbon dioxide gas is pressurized into the room temperature leg vessel, and the internal pressure is maintained at 3 Ky/cr& to carry out carbonation for about 30 minutes.

In this way, amorphous silica-calcium carbonate composite particles (Silsite ■) are obtained.

The results of the analysis are as follows.

Composition (H) St Q2B 9.77 CGO31,43 AJ32030, 24 Fe 203 0-40 μg・1oss 27-42 Total 99-26 The X-ray diffraction results are the same as shown in Figure 1 (G). All the peaks characteristic of the tobermolite crystal used as the starting material disappeared, and the temperature was 9K 23.0°, 24.8°.
, 27.0.29.4, only the diffraction peaks (2θ) of calcium carbonate crystals appeared at 32.8° and 36.0°. It is converted to calcium carbonate.

Furthermore, the results of electron microscopy are shown in Figure 3. As shown in the figure, the composite particle has at least two symmetrical surfaces, a length of about 1 to 20 μm, and a length of about 0.02 to 0.1 μm.
of amorphous silica having a thickness of approximately 0.2 to 5.0μ, and a length of at least 10 times the thickness.
It can be seen that the calcium carbonate fine particles having the form of ultrafine particles of less than .mu.m are attached and maintain the plate-like outer shape as they are.

This composite particle is obtained by dispersing it in water at a concentration of 5% by weight,
After stirring for 20 minutes and then leaving to stand, the silica and calcium carbonate constituting the particles could not be separated at all even if they were attempted to be separated by sedimentation due to the difference in specific gravity, indicating that the two were firmly attached chemically or physically. Is recognized.

The characteristics of Silsite I obtained above are shown below.

Bulk density 0-101? /cr/1 Specific surface area 55 m'/f Oil absorption 300cc/10 (1 In addition, the state of the pore size distribution of the above-mentioned Silsai!-■ is shown in Figure 5 by curve (2), and that is shown in 23A. A peak is observed.

The slurry of the present invention is obtained by dispersing the silzite obtained above in water such that the weight ratio of water to solid content is 5:1.

Next, the resulting aqueous slurry is placed in a mold, dehydrated, and then dried to obtain a molded body. The physical properties of the obtained molded article are shown below.

Bulk density 0.5Of/m Porosity 80.0% Heat resistance at 950°C No change Compressive strength 15 ni/CIIL Bending strength 8~/d Example 3 Obtained in Reference Example 3. ; Seirolite plate-like crystal-order particles are used as a starting material. This is placed in a closed pressure vessel together with 5 times its weight of water, carbon dioxide scum is pressurized into the room temperature leg vessel, and carbonation is carried out for about 30 minutes while maintaining the internal pressure at 3 Kp/cwt.

In this way, amorphous silica-calcium carbonate composite particles are obtained.

The results of the analysis are as follows.

Composition (%) St C)2 48-22 CaO26,07 Al12030.33 i;"e2030.25 1g・1oss 24.33 Totel 99-20 The XMI diffraction results are shown in Figure 1 (G). Similarly, all the peaks peculiar to the calcium silicate crystal used as the starting material disappeared and the peak was reduced to 23.00.24.8
°, 27.0°, 29.4°, 32.8° and 36.0
Only the diffraction peak (2θ) of the calcium carbonate crystal appears in '. Carbonated calcium silicate is converted to amorphous silica and calcium carbonate.

Furthermore, according to the results of electron microscopy, the composite particles have at least two symmetrical surfaces, a length of about 1 to 20 μm, a thickness of about 0.02 to 0.1 μm, and a thickness of about 0.2 to 5 μm.
Calcium carbonate microparticles in the form of ultrafine particles of about 2 μm or less are attached to amorphous silica having a width of about 10% and a length about 10 times or more the thickness. The external shape of the amorphous silica is maintained as it is.

This composite particle is obtained by dispersing it in water at a concentration of 5% by weight,
After stirring for 20 minutes and then leaving to stand, the silica and calcium carbonate constituting the particles could not be separated at all even if they were attempted to be separated by sedimentation due to the difference in specific gravity, indicating that the two were firmly attached chemically or physically. Is recognized.

The characteristics of Silsite (■) obtained above are shown below.

Bulk density 0.1B5f/d Specific surface area 50m"/? Oil absorption 260cc/10 (1) Furthermore, the state of the pore size distribution of Silsite I is shown in Figure 5 as curve #J f3). The peak can be seen in .

The aqueous slurry of the present invention is obtained by dispersing Silsite I obtained above in water such that the weight ratio of water to solids is 5:1. This material has the ability to form a molded product that is lightweight and has mechanical strength simply by dehydration molding and drying.

Example 4 The α-tai calcium silicate hydrate plate-shaped crystal-missing particles obtained in Reference Example 4 were used as a starting material. This was placed in a closed pressure vessel together with 5 times its weight of water, carbon dioxide gas was pressurized into the room-temperature leg vessel, and the internal pressure was maintained at 3 Kf/ffl to carry out carbonation for about 30 minutes.

In this way, amorphous silica-calcium carbonate composite particles (Silsite ■) are obtained.

The results of the analysis are as follows.

Composition (%) StO222,86 CaO42-24 M2030.31 pe2o30.33 Ig-1oss 34.50 Total 100.2 The X-ray diffraction results are the same as those shown in the first analysis. All the peaks peculiar to calcium crystals disappeared and the peaks were 23.0°, 24.8°, and 27.0°.
Only the diffraction peaks (2θ) of calcium carbonate crystals appear at 29.4°, 32.8°, and 36.0°.

Carbonation converts calcium silicate into amorphous silica and calcium carbonate.

Further, according to the results of electron microscopy, the composite particles have at least two planes that are symmetrically arranged as shown in FIG. Calcium carbonate fine particles in the form of ultrafine particles of about 2 μm or less are attached to amorphous silica having a width of about 1 to 30 μm and a length of at least 10 times the thickness. ing. The shape of the above amorphous silica is α
- It is exactly the same as that of the calcium silicate hydrate plate crystal (FIG. 4(A)), and the crystal habit is maintained as it is.

This composite particle is obtained by dispersing it in water at a concentration of 5% by weight,
After stirring for 20 minutes and then leaving to stand, the silica and calcium carbonate constituting the particles could not be separated at all even if they were attempted to be separated by sedimentation due to the difference in specific gravity, indicating that the two were firmly attached chemically or physically. Is recognized.

The characteristics of Silsite I obtained above are shown below.

Bulk density 0.656 y/cd Specific surface area g,,l/y Oil absorption 100CC/100r Furthermore, the state of the pore size distribution of Silsite I is shown in Figure 5 by curve (4), 24λ. The peak can be seen in .

The aqueous slurry of the present invention is obtained by dispersing the Silsite (2) obtained above in water such that the weight ratio of water to solids is 52I. This material has the ability to form a molded product that is lightweight and has mechanical strength simply by dehydration molding and drying.

[Brief explanation of drawings]

FIG. 1 is an X-ray diffraction diagram. In the diagram, (2) shows the starting material, linotrite crystal, and the part (2) shows silsite I obtained from the crystal. Figures 2 and 3 are electron micrographs, and in each figure (8
) indicates the starting material, calcium silicate crystal, and (g) indicates Silsite I obtained from the crystal. FIG. 4 is an electron micrograph, in which (2) shows the α-C2SH crystal that is the starting material, and (g) shows Silsite I obtained from the crystal. FIG. 5 is a pore size distribution map of Silsite I. Figure 1 Circulation angle (2θ) - Magu hole I5 (in) □

Claims (1)

[Claims] ■ Has at least two symmetrical faces, approximately 1
~500μ in length and a thickness of about 50λ to about 1μ, consisting of crystal-like amorphous silica in appearance, the length being at least 10 times the thickness, and ultrafine calcium carbonate attached to the silica. A molding material made by dispersing silica-calcium carbonate composite particles in water.