JP3142767B2 - Manufacturing method of synthetic mica - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing synthetic mica by an internal heat melting method. More specifically, the present invention relates to a method for producing synthetic mica having good crystallinity which can be pulverized into synthetic mica powder having a large aspect ratio. The present invention relates to a method of manufacturing at low cost.

[0002]

2. Description of the Related Art Synthetic mica is used for heat insulating materials, paints, resin fillers, welding rods, lubricating materials, etc. by utilizing its excellent insulating properties, heat insulating properties, reefing properties and lubricating properties. Medicine
It is used for many purposes such as cosmetics, pigments, catalysts, mica aggregates, and machinable ceramics.

[0003] As a method for producing the synthetic mica, an internal heat melting method and an external heat melting method are conventionally known. As an external heating type melting method, Japanese Patent Publication No. 37-8587 discloses a method of adding a seed crystal to a flat container.
No. 230 discloses a method for producing mica crystals using seed crystals.

[0004] As for the internal heat type melting method, a clay handbook (Gihodo Shuppan) discloses a melting method which does not use a crucible which consumes a small amount of electricity and which can be melted in a large amount. In this method, a sintered layer is generated between the molten material and the unmelted material, and this serves as a container for the molten material.Therefore, there is no need to use a crucible, and since the surroundings are surrounded by the raw materials, A relatively large synthetic mica crystal is obtained. Also, Japanese Patent Application Laid-Open
In the “Method for producing a fluorine-containing layered structure” of JP-A-123267, the supply and melting of the blended raw material are performed by forming a through hole in the molten shell and taking out the melt from the through hole into a mold. , A melting method characterized by performing repeatedly.

[0005]

The external heat melting method described above has low productivity and therefore requires a high production cost. Therefore, the internal heat melting method with high production efficiency is used industrially.
However, the internal heat melting method described in the clay handbook requires a long time to cool down, and is a batch method, so that productivity is poor, and in order to take out synthetic mica crystals,
Since the work of shaving the unmelted portion and the sintered layer portion is required, and the work cannot be completely shaved, there is a problem that these are mixed as impurities.

[0006] The melting method of taking out the molten material into the mold is excellent in productivity, but the molten material is inevitably fluidized, so that only small crystalline synthetic mica having poor crystallinity can be obtained. When it is milled into mica powder, the mica powder cannot be formed into a flake shape with a smooth surface and becomes an irregular shaped powder having a jagged cross section and surface. I can't get it. Therefore, it was extremely unsatisfactory for use as a substrate for pearl luster pigments requiring an aspect ratio or as a raw material for laminated mica. This is also described in Japanese Patent Publication No. 47-24930.

[0007] A conventional melting method for taking out a melt in a mold is as follows.
As described in page 6, line 18 of the above publication, the purpose is to "shorten the cooling time of the melt", and is intended to produce a synthetic mica having good crystallinity as in the present invention. It does not do. Therefore, a form without heat insulation is used. In short, it was thought that only the small crystalline synthetic mica could be obtained because this melting method inevitably causes fluidization, so even small crystalline synthetic mica can be used as a production method for applications that do not interfere. It has been. An object of the present invention is to provide a method for producing synthetic mica which can continuously produce synthetic mica having good crystallinity which can be pulverized into synthetic mica powder having a large aspect ratio by an internal heat melting method. I do.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the melt was cooled and crystallized in an insulated container to obtain a flake having a smooth surface. The present inventors have found that a synthetic mica having good crystallinity which can be pulverized is obtained, and the present invention has been achieved.

That is, according to the present invention, after the synthetic mica raw material is melted by the internal heat type melting method, the resulting melt is converted into a material having a thermal conductivity.
0.2 Kcal / m. h ° C or less and thickness 50mm or less
After being taken out into the heat insulating container and crystallized in the heat insulating container, the synthetic mica was pulverized to an aspect ratio of 50.
１０００1000 synthetic mica powder .

The synthetic mica used in the present invention is represented by the following general formula. X _{1/3 to 1} Y _2-3 Z ₄ O ₁₀ F _{2 In the} above formula, the substitutable elements at the positions of X, Y and Z are shown in the form of ions as follows. X; Na ⁺ , Li ⁺ , K ⁺ , Ca2 ⁺ , Sr2 ⁺ , Ba2 ⁺ Y; Mg2 ⁺ , Li ⁺ , Ni2 ⁺ , Co2 ⁺ , Zn2 ⁺ , M
n ²⁺ , Al ³⁺ , Cr ³⁺ , Ti ²⁺ Z; Al ³⁺ , Si ⁴⁺ , Ge ⁴⁺ , B ³⁺

As the synthetic mica raw material used in the present invention, those used in the conventionally known internal combustion type melting method can be used. For example, SiO ₂ , MgO, Al ₂ O ₃ , K ₂
CO ₃ and fluoride (NaF, LiF, KF, Na ₂ Si
F ₆ , K ₂ SiF _6, etc.) may be mixed and used according to the intended chemical composition. Natural minerals such as feldspar, olivine, and talc may be used as Si, Al and Mg sources. In the case of producing synthetic mica in which X, Y, and Z are substituted with another element, an oxide, a fluoride, a carbonate, or the like of the element to be substituted may be blended with the above mixture and melted.

[0012] The heat-insulating container used in the present invention can receive a molten material, and if it has heat-insulating properties, its shape,
The material is not particularly limited. Various shapes such as a cube, a rectangular parallelepiped, a cylinder, an elliptic cylinder, a sphere, a triangular prism, and a trapezoid can be used.

Materials include metal, brick, ceramic,
Graphite or the like can be suitably used. When using a mold with good thermal conductivity, such as metal or graphite, use ceramic fibers around the
It is necessary to wind or attach a heat insulating material such as a ceramic board. In order to further improve the heat insulating property, it is preferable to use a heat insulating brick or to interpose an air layer therebetween. In order to interpose an air layer, a space may be formed between walls forming the heat insulating container, or an air-containing material such as ceramic wool may be interposed.

As a method of taking out the melt into the heat insulating container, for example, a through hole is formed in a molten shell formed around the melt and the melt is taken out from the through hole, or the melting furnace is inclined. Examples of the method include a method of taking out the material, and other methods may be used, and the method is not limited thereto. The thermal conductivity of the heat insulating container used in the present invention is 0.2 Kcal / m.
hC or lower, preferably 0.1 Kcal / m. Der h ℃ below
You . The thickness of the heat-insulating container, 50mm or more preferably 100mm or more.

Further, the heat insulating container is provided with a gas burner,
It is preferable to preheat to a temperature near the temperature of the melt by a heat transfer heater or the like. Since the synthetic mica produced as described above has good crystallinity, large synthetic mica crystals can be obtained. That is, according to the conventional method in which the molten shell is perforated and taken out into the mold, only synthetic mica having a size of 10 mm to 20 mm can be obtained.
Synthetic mica having a size of not less than mm can be easily obtained.

The synthetic mica obtained by the method of the present invention not only has a large crystal but also has excellent crystallinity, so that when it is pulverized, a synthetic mica powder having a large aspect ratio can be easily obtained. That is, the synthetic mica obtained by the conventional method can obtain only a synthetic mica powder having an aspect ratio of 40 or less, but the synthetic mica obtained by the method of the present invention can easily obtain a powder having an aspect ratio of 50 to 1000.

[0017]

Next, the present invention will be further described with reference to examples and comparative examples, but the present invention is not limited to these examples. Example 1 A melting furnace was provided with an outlet for discharging the melt on one side, and three carbon-made electrodes were disposed inside.

Approximately 200 kg of a raw material prepared in a weight ratio of about 40 parts of silicic anhydride, about 30 parts of magnesium oxide, about 13 parts of aluminum oxide, and about 17 parts of potassium silicofluoride is accommodated in the melting furnace, and energized for about 2 hours. To produce a melt. A through-hole is formed in the molten shell formed around the melt from an outlet, and the melt is caused to flow out of the furnace through the through-hole, and a ceramic fiber is formed around the insulating brick.
Thermal conductivity with ceramic board bonded through
It was received in a heat-insulated container having a thickness of 150 mm at 1 Kcal / m · h ° C. After cooling, the size of the obtained synthetic mica crystal is 7c.
m. When this synthetic mica crystal was pulverized, a synthetic mica powder having an aspect ratio of about 500 was obtained. For comparison, a synthetic mica crystal produced in the same manner except that a conventional frame was used had a size of 1 cm, and the powder after crushing the crystal had an aspect ratio of 40.

Example 2 About 200 kg of a raw material prepared in a weight ratio of about 58 parts of silicic anhydride, about 22 parts of magnesium oxide, about 26 parts of sodium silicofluoride, and 11 parts of lithium carbonate was used in the melting furnace of Example 1. And melted similarly to synthesize sodium teniolite crystals. The size of the obtained synthetic mica crystal is 1c.
m, and the aspect ratio after pulverizing the crystal was 150. For comparison, the size of the synthetic mica crystal produced in the same manner except that the conventional frame was used was 0.1 c.
m, and the powder after pulverization had an aspect ratio of 30.

Example 3 About 34 parts of silicic anhydride, about 18 parts of magnesium oxide, about 11 parts of aluminum oxide, about 25 parts of potassium silicofluoride,
Approximately 200 kg of raw material prepared at a weight ratio of approximately 12 parts of iron oxide
And melted in the same manner as in Example 1 except that the electrode was changed to an iron electrode, to synthesize iron-substituted fluorophlogopite. The size of the obtained synthetic mica crystal is 5c.
m, and the aspect ratio of the powder after grinding was about 500. For comparison, the size of the synthetic mica crystal produced in the same manner except that a conventional frame was used was 1 cm, and the powder had an aspect ratio of 40 after pulverization.

The reason why the method of the present invention can provide large synthetic mica with good crystallinity compared to the conventional method is that the heat insulating container prevents heat radiation, thereby lowering the cooling rate and at the same time, reducing the temperature of the melt. Convection in an insulated container,
It is considered that the temperature and components of the melt were made uniform. The reason why the aspect ratio of the powder after the synthesis of the synthetic mica powder is increased is that the crystal size of the obtained synthetic mica is large and the crystallinity is good.

The synthetic mica of the present invention produced as described above is used for heat insulating materials, paints, resin fillers, welding rods,
For lubricants, cosmetics, pigments, catalysts, laminated mica,
It can be used for all conventional synthetic mica applications such as machinable ceramics.

[0023]

As described above, the synthetic mica produced by the method of the present invention has good crystallinity and is a crystal larger than that obtained by the conventional method. Since a synthetic mica powder is obtained, a base material of a pearl pigment, which particularly requires an aspect ratio,
It is extremely useful for applications such as aggregate mica raw materials.

Continuation of the front page (56) References JP-A-51-123267 (JP, A) JP-A-5-270815 (JP, A) Clay Handbook, 2nd edition, edited by The Clay Society of Japan, Gihodo Shuppan Co., Ltd., April 1987 March 30, p. 235-236 (58) Field surveyed (Int. Cl. ⁷ , DB name) C01B 33/20-33/44 JICST file (JOIS)

Claims (7)

(57) [Claims] After melting a synthetic mica raw material by an internal heat melting method, the resulting melt is subjected to a heat conductivity of 0.2 Kcal /
m. and a thickness of at h ° C. or less taken up in more heat-insulating container 50 mm, after crystallization in the cross heat container, the synthetic
Combine mica to produce an aspect ratio of 50-1000
A method for producing synthetic mica, comprising mica powder . 2. The method according to claim 1, wherein the heat insulating container is preheated before the melt is taken out. 3. The method according to claim 1, wherein the heat-insulating container is formed by interposing an air layer in a wall constituting the container. Wherein the thermal conductivity of the heat-insulating container, 0.1Kc
al / m. The production method according to any one of claims 1 to 3, wherein the temperature is hC or lower. The thickness of claim 5 wherein said heat-insulating container, a manufacturing method according to any one of claims 1 to 4 is 100mm or more. 6. The obtained synthetic mica crystal has a size of 30
The process according to any one of claims 1 to 5, in mm. 7. bored through holes in the molten shell formed around the melt according to any one of claims 1 to 6, taking out the melt in the heat-insulating container from said through hole Manufacturing method.