JPS598657A - Calcium silicate moldings and manufacture - 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] The present invention relates to a calcium silicate molded body and a method for producing the same.

Calcium silicate molded bodies are widely used in various fields because they have many properties such as being flexible, having excellent heat insulation properties, and having high fire resistance. Furthermore, there are various types of crystals of calcium silicate, such as those of the tobermolite group and those of the wollastonite group, and various manufacturing methods are known.

The present inventor has been conducting research on calcium silicate molded bodies and methods for producing the same, and in this research, when the mountain skin is uniformly dispersed and contained in the molded body, it is difficult to bend the molded body. It has been found that the strength and the residual strength rate after firing are greatly improved. As I continued my research, I also discovered the following new facts.

That is, for calcium silicate molded bodies containing mountain skin, (1) the bending strength of the molded body varies greatly depending on the means of containing the mountain skin, (11) regardless of the difference in the means of containing the mountain skin, The residual strength rate after firing of the molded body is improved (when adding 110 mountain bark to the raw material slurry, the solid content layer of the raw material slurry containing mountain bark is added in an amount of 0.01 to 0.4% by weight). The addition of such a small amount significantly improves the bending strength of the resulting molded product, but as the amount exceeds 0.4% by weight, the bending strength decreases.

(lv) When adding mountain bark to the calcium silicate crystal slurry after a hydrothermal synthesis reaction, the bending strength increases due to the addition of mountain bark, but drying shrinkage tends to increase as the amount added increases. 4- The appropriate amount of addition thereof to the crystal slurry containing the mountain bark is about 0.4 to 10%.

The present invention has been completed based on the discovery of these new facts.

The present invention will be explained below based on its manufacturing method.

A raw material slurry is prepared from. Both crystalline and amorphous silicic acid raw materials can be used as silicic acid raw materials, and for the former, those containing crystalline silicic acid as the main component can be widely used, such as silica sand, silica stone, quartzite, etc., and for the latter, amorphous silicic acid raw materials can be used. Various amorphous silicic acids containing silicic acid as a main component can be used, and specific examples include diatomaceous earth, white carbon, silica flour, and silicon dust.

Various types of lime raw materials can be used as raw materials for Saruda lime, and typical examples include quicklime, slaked lime, and carbide residue. Mountain leather refers to hydrated magnesium silicate minerals, such as seviolite, palygorskite, attapulgite, commonly called mountain leather, mountain cork, mersham (meerschaum), etc. Either mountain bark raw stone or commercially available products may be used.

Additionally, some mountain bark may contain calcium carbonate, but in such cases it is best to crush or separate it before use. At this time, the amount of Somoto-Yamahi added is 0.0 in the total weight of the solid content of the raw material slurry and Yamahiki.
The content is 1 to 0.4% by weight, preferably 0.08 to 0.8% by weight. In this case, if the amount does not reach 0.01% by weight, the bending strength of the obtained molded product will not be sufficiently improved;
When the amount exceeds 4% by weight, the bending strength of the molded article tends to decrease as well. The amount of water is 15 times or more by weight, preferably 18 to 40 times the solid content.

The raw material slurry thus prepared is then stirred and heated under pressure to form a slurry of calcium silicate crystals. The conditions at this time are a saturated water vapor pressure of 5 ktiy- or more, and the reaction time is appropriately selected depending on the vapor pressure and the type of calcium silicate crystal desired. For example, in the case of tobermolite, the saturated water vapor pressure is 1. 8 hours in 4, 8 illusions, /c
-, it takes about 6 hours.

In addition, in the case of thonodolite, it takes 2 hours to visit 15 yen, and 12 hrs.
It takes about 4 hours south of KTI.

Through this hydrothermal synthesis reaction, a calcium silicate crystal slurry is obtained in which a large number of calcium silicate MAs are entangled and a large number of approximately spherical secondary particles are dispersed in water. At this time, if the raw material slurry contains mountain bark, it means that mountain bark is mixed in the secondary particles.

As described above, in the present invention, an aqueous slurry in which a large number of secondary particles of calcium silicate crystals are dispersed in water is produced. The density of the particles will be different. For example, when using crystalline silicic acid raw material 7-, if a special lime milk with a sedimentation capacity of 5 or more is used as the lime raw material, o, 1 f.
It has the advantage of being able to obtain lightweight secondary particles of lcdm degree, and if special lime milk is not used as mentioned above, it is difficult to obtain @violet particles of about 0.11/d, so Large secondary particles can be obtained. When using amorphous silicic acid raw material, even if ordinary lime raw material is used, it is possible to obtain secondary particles in an amount of about 0,1 yyct, and the above-mentioned special method with a sedimentation volume of 5 m1 or more can be obtained. When milk of lime is used, extremely light secondary particles with a density of about 0.04 f/d can be obtained.

A large sedimentation volume means that the lime is well dispersed in water and in a stable state, that is, it is composed of extremely fine particles.
Therefore, it means that it shows high reactivity. Sedimentation volume is 5
The method itself for producing milk of lime of m1 or more is a commercial method and is not particularly limited.

The sedimentation volume of this milk of lime depends on the limestone itself used as a raw material, the firing temperature during lime production, the amount of water when slaked lime with water, the temperature at that time, the stirring conditions at that time, etc. This is greatly affected by the temperature and stirring conditions during slaking, but in any case, it is not possible to obtain lime milk with the desired sedimentation valley*5 m or more using the usual method for producing milk of lime. Therefore, milk of lime with a sedimentation volume of $5 ml or more is typically stirred at high speed or vigorously at a water to lime content (solid content) ratio of 6 times ([amount)] or more, preferably at a temperature of 60'0 or more. Alternatively, the powder may be wet-milled using a wet-mill, and then left to disperse. For example, the desired milk of lime can be obtained by vigorous stirring using a homomixer.

The stirring speed and stirring intensity can generally be lowered by increasing the temperature and lengthening the stirring time. For example, even lime milk slaked at 20°C can be made into the desired lime milk by stirring it for a long time with a homomixer. Various types of stirrers can be used, and those with or without baffles can be used.

In the present invention, the thus obtained calcium silicate crystal slurry is then molded and dried to obtain a calcium silicate molded body. Prior to this molding, it is preferable to incorporate 0.4 to 10% by weight of husk, preferably 1 to 6% by weight, in the total weight of the lath slurry and husk. The addition of this mountain skin significantly improves the bending strength of the molded body and the residual strength rate after firing. In this case, if the content is less than 0.4% by weight, the above effects will not be fully exhibited, and even if it exceeds 10% by weight, not only will no further effect be expected, but as the content increases, This is not preferable since drying shrinkage tends to increase. In this way, when adding a ridge to an aqueous slurry of calcium silicate crystals, the ridge is not present in the secondary particles of calcium silicate crystals, but is uniformly distributed in the water, with or without contact with the secondary particles. Dispersed.

In the present invention, the calcium silicate molded body can contain a normal reinforcing material, and in this case, any reinforcing material that has been conventionally used can be used, such as delicate materials, clay, etc. Examples include cements, gypsum, colloidal silica, alumina sol, etc., and examples of more delicate materials include asbestos, rock wool, glass fiber, aged lamic fiber, carbon delicacy, inorganic materials such as metal fiber, polyamide, and polyester. Examples include various synthetic fibers, pulp, and organic delicacies such as various natural substances such as sylulose, clays such as kaolin, bentonite, pyrophyllite, etc., and cements such as Portland cement, alumina cement, etc. I can give an example. As means for containing these reinforcing materials, there are two methods: adding reinforcing materials to the raw material slurry (hereinafter referred to as pre-adding means);
Means of adding reinforcement to calcium silicate crystal slurry (
In the case of the first-in means, inorganic fine material is usually used, and in the case of the last-in means, a wide variety of reinforcing materials can be used.

The molded article of the present invention has preferential orientation similar to the conventional molded article produced from a calcium silicate crystal slurry.

The present invention will be specifically explained below with reference to Examples and Comparative Examples. In the following Examples, "part" or "%" means "Km part" or "wt%" unless otherwise specified.

Example 1 (first addition of Seviolite) 45.88 parts of quicklime was slaked in 650 parts of warm water at 80°C, and the sedimentation volume of milk of lime obtained by dispersing it in water for 2 minutes using a homomixer was 16.0 to 15. It was 8 ml.

Slurry obtained by dispersing a predetermined amount of Seviolite (produced in China, with some calcium carbonate mixed in) in the above milk of lime with 200 times its weight of water using a mixer and silica powder with an average particle size of approximately 9 μm. 49.68 parts were added and mixed so that the total weight of the water filter was 22 times the solid content to obtain a raw material slurry. Next, these were subjected to a hydrothermal synthesis reaction for 2 hours at a saturated water vapor pressure of 15 kgM, a temperature of 200.4"C, a volume of 8000 m, and an inner diameter of 15 cm in an autoclave with a rotation speed of 174 r, p, m, while rotating the stirring blades simultaneously. A crystal slurry was obtained. These crystal slurries were dried at 100°C for 24 hours and analyzed by X-ray diffraction, and it was confirmed that they were xonotrite crystals. These crystal slurries were dried on a slide glass and optically analyzed. When observed under a microscope, spherical secondary particles having the outer diameter shown in Table 1 below were observed.

Next, 7 parts of glass fiber I#, 5 parts of pulp, and 8 parts of Portland cement were added as additives to 85 parts (solid content) of the above crystal slurry, and the mixture was press-molded and dried at 120°C for 20 hours to obtain a molded product. Ta. The physical properties of the obtained molded product were as shown in Table 1 below.

Example 2 (first addition of Seviolite) The sedimentation volume of milk of lime obtained by slaking 41.42 parts of quicklime in 497 parts of warm water at 80°C was 4.8 to 4.9 parts. 0.0518 parts (0,0592% by weight) in the above milk of lime
The slurry obtained by dispersing Seviolite (produced in China) in 200 times the amount of water in a mixer for 2 minutes and the average particle mo,
Add the slurry obtained by dispersing 25μm fer silicon dust 46.0H in 1120 times the amount of water in a homomixer for 2 minutes and mix so that the total amount of water becomes 24 and 80 times the amount of solid water to make the raw material slurry. I got it. Next, these were heated to a saturated water vapor pressure of 16 Q/d and a temperature of 200.4°C.
In an autoclave with a volume of 8000 cc and an inner diameter of 153, the stirring blades were rotated at the same rotation speed of 112 r, p, and m.
A hydrothermal synthesis reaction was carried out for a period of time to obtain a crystal slurry. These crystal slurries were dried at 100°C for 24 hours and subjected to X-ray diffraction analysis, which confirmed that they were sheet dried crystals. Further, when these crystal slurries were dried on a slide glass and observed under an optical microscope, spherical secondary particles with outer diameters shown in Table 2 below were observed.

Next, 7 parts of glass delicacy, 6 parts of pulp, and 8 parts of Portland cement were added as additives to 85 parts (solid content) of the crystal slurry, which was then press-molded and dried at 120° C. for 20 hours to obtain a molded product. The physical properties of the obtained molded product are shown in the second section below.
It was as shown in the table.

16- Example 8 (Seviolite pre-loading) 41.42 parts of quicklime was slaked in 497 parts of warm water at 80°C, and the sedimentation volume of milk of lime obtained by dispersing it in water for 8 minutes using a homomixer was 16. It was 8 to 17.5 tel.

A slurry obtained by dispersing a predetermined amount of Seviolite (manufactured by Takeda Pharmaceutical, trade name, Needplus ML-100D) in the above milk of lime with 200 times its weight of water using a mixer for 2 minutes and silica powder with an average particle size of 9 μm 54.04 parts were added and mixed so that the total amount of water was 22 times the weight of the solid content to obtain a raw material slurry. These were then subjected to a saturated water vapor pressure of 12 kt.
i/d, a temperature of 191°C, a volume of 8000 cc, an inner diameter of '15 cIIl, and a rotation speed of 14 Or.
A hydrothermal synthesis reaction was carried out for 8 hours while rotating the stirring blade at p and m to obtain a crystal slurry. 10 of these crystal slurries
After drying at 0°C for 24 hours and performing X-ray diffraction analysis, it was confirmed that it was tobermolite crystal. Further, when these crystal slurries were dried on a slide glass and observed under an optical microscope, spherical secondary particles having the outer diameters shown in Table 8 below were observed.

Next, 4,611,467 parts of glass, 5 parts of pulp, and 8 parts of Portland cement were added as additives to 85 parts (solid content) of the above crystal slurry, and the mixture was press-molded and heated at 120°C for 2 hours.
A molded article was obtained by drying for 0 hours. The physical properties of the obtained molded product were as shown in Table 8 below.

19-20 Example 4 (Post-addition of sepiolite) The sedimentation volume of milk of lime obtained by slaking 41.42 parts of quicklime in 497 parts of warm water at 80°C was 4.8 g/. A slurry obtained by dispersing 46.08 parts of ferrosilicon dust with an average particle size of 0.26 μm in 20 times the weight of water using a homomixer for 2 minutes was added to the above milk of lime, and the total amount of water was made 24 times the weight of the solids. A raw material slurry was obtained by mixing the ingredients. Next, this was heated to a saturated water vapor pressure of 1549/d and a temperature of 2
A hydrothermal synthesis reaction was carried out at 0.4°C for 2 hours in an autoclave having a volume of 8000 cc and an inner diameter of 15 cIs while rotating stirring blades at a rotation speed of 112 r, p, m to obtain a slurry consisting of xonotrite crystals.

Next, 7 parts of glass fiber, 6 parts of pulp, 8 parts of Portland cement, and the following 4th part were added to the crystal slurry as additives.
A slurry obtained by dispersing the amount of Seviolite (produced in China, with some calcium carbonate mixed in) shown in the table in 100 times its weight of water in a mixer for 2 minutes was added, and the mixture was press-molded at 120°C. The molded product was obtained by drying for 20 hours. The physical properties of the obtained molded product were as shown in Table 4 below.

Example 5 (adding sepiolite) 45.88 parts of quicklime was slaked in 550 parts of warm water at 80°C, and the lime milk obtained by dispersing it in water for 8 minutes using a homomixer had a sedimentation volume of 20 resistant. . 49.68 parts of silica powder having an average particle diameter of about 9 μm was added to the above milk of lime and mixed so that the total amount of water was 22 times the weight of the solid content to obtain a raw material slurry. Next, this was adjusted to a saturated water vapor pressure of 15 kg/d.
, temperature 200.4℃, volume 8000ω, inner diameter 15(:I
A hydrothermal synthesis reaction was carried out for 2 hours while rotating the stirring blade at a rotation speed of 174 r, p, m in an autoclave of I, to obtain a slurry consisting of xonotrite crystals.

Next, glass m1m7 was added to the crystal slurry as an additive.
1 part, 5 parts of pulp, 8 parts of Portland cement, and the amounts shown in Table 5 below of Seviolite (manufactured by Kyoiku Yakuhin, trade name, Need Plus ML-100D) were dispersed in 10,000 weight parts of water using a mixer for 2 minutes. Add slurry;
It was press-molded and dried at 120'0 for 20 hours to obtain a molded body.

Claims (1)

[Scope of Claims] ■ A molded body composed of spherical secondary particles formed by aggregation of calcium silicate crystals connected to each other in a compressed and deformed state, the molded body having a mountain crust in it. A calcium silicate molded body characterized by uniformly containing. (2) The molded article according to claim 1, wherein the content of mountain bark is about 0.01 to 10% by weight. (2) The molded article according to claim 1, wherein the content of mountain bark is about 0.01 to 0.4% by weight. (2) The molded article according to claim 1 or 8, wherein most of the mountain skin forms spherical secondary particles together with calcium silicate crystals. ■ Mountain bark content is greater than 0.4% by weight and 10% by weight
A molded article according to claim 1 which is as follows. (2) The molded article according to claim 1 or 5, in which most of the mountain skin does not form spherical secondary particles together with calcium silicate crystals. ■ The density of the spherical secondary particles before molding is about 0.05 to about 0,
11/d. (2) The molded article according to claim 1, wherein the calcium silicate crystals are mainly composed of tobermolite crystals. (2) The molded article according to claim 1, wherein the calcium silicate crystals are mainly composed of sheet dried crystals. [Phase] A raw material slurry prepared by mixing silicic acid raw materials and lime raw materials with water with or without mountain bark is heated under pressure and stirred to cause a hydrothermal reaction to form a calcium silicate crystal slurry. A method for producing a calcium silicate molded article, which comprises adding mountain bark or molding and drying without adding mountain bark when mountain bark is added to a raw material slurry. ■ The manufacturing method according to claim 10, characterized in that a raw material slurry containing mountain bark is used. @ The content of mountain bark is 0.0 in the total weight of silicic acid raw material, lime raw material, and mountain bark. 12. The method of claim 11, wherein O is 1 to 0.4% by weight. [Phase] The manufacturing method according to claim 10, characterized in that mountain bark is added to the calcium silicate crystal slurry. 0. The manufacturing method according to claim 1e, wherein the content of mountain skin is more than 0.4% by weight and 10% by weight or less in the total N amount of the solid content and mountain skin in the calcium silicate crystal slurry. [Phase] Claim 10 in which the silicic acid raw material is amorphous
Manufacturing method. [Phase] The production method according to claim 10, which uses milk of lime having a sedimentation volume of 5 m1 or more as the lime raw material. (2) The manufacturing method according to claim 10, wherein the silicic acid raw material is amorphous and the lime raw material is milk ash having a sedimentation capacity of N 5 xttm6 or more.