JP2014037341A - White mesoporous ceramics using diatomaceous earth - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome a problem of a mesoporous ceramics using a conventional diatomaceous earth, which is a bottlenecks for application expands due to limitation of color tone by color development of iron included in the conventional diatomaceous earth.SOLUTION: A mesoporous ceramics having both of functional properties and designability is able to be manufactured by using diatomaceous earth produced in Menashibetsu, Wakkanai-shi, Hokkaido and formed by geological diagenesis of strong reduction and whitening by oxidation firing at 600 to 1000°C.

Description

Detailed Description of the Invention

  The present invention relates to white mesoporous ceramics (hereinafter referred to as MPC) having a high design property utilizing mesopore type diatomaceous earth produced by Meriashi, Wakkanai City, Hokkaido.

  Humidity control ceramics known as MPC are produced using diatomaceous earth. MPC is a functional ceramic that controls the absolute humidity by the autonomous moisture absorption / release function of mesopores having a pore diameter of 50 nm or less and suppresses fluctuations in relative humidity. It is an environmental material that is positioned in the field of nanotechnology. When this material is applied to the field of architecture, it is possible to prevent harmful effects caused by excess or deficiency of moisture and improve the durability of the house. In addition, mesopores including micropores having a pore diameter of 50 nm or less adsorb toxic chemicals, harmful gases such as carbon monoxide, malodor, and oil mist, making the indoor environment healthy and comfortable. Although the functions and effects of such MPC have been proven and evaluated, the industry has not spread so much. The biggest factor lies in the design, and the fact that MPC with high whiteness that enables various color tones has not been developed.

  Diatomaceous earth is used as a functional raw material because of its porous properties and functions, which are governed by the pore structure and are not related to the lithology and lithology. Therefore, the names of diatomaceous earth resources and their raw materials are rationally expressed by the concept that characterizes the pore structure, and here they are called broadly as macropore type and mesopore type.

  The pores are classified into three types depending on the size, and pores having a diameter of 2 nm or less are called micropores, 2 to 50 nm are called mesopores, and 50 nm or more are called macropores.

  A wide variety of diatomaceous earth is widely distributed in Hokkaido. As the mesopore type, diatomaceous earth of the stratum called Wakkanai Formation, Asagino Formation, and 17 Line River Formation is known as a raw material for MPC. For example, the inventor of the present application is the “manufacturing method of humidity control functional material using Wakkanai layer diatomaceous earth” (Patent No. 2652593), “humidity control ceramic building material” (Patent No. 2964393), “humidity control building material” (Patent No. 3659867) and the like. (See Patent Document 1, Patent Document 2, and Patent Document 3)

  Mesopore-type diatomite is a macropore type that has been altered by geological diagenesis, and its occurrence, lithology, and lithology vary from site to site. For example, most of the Wakkanai Formation is rock-like, but some of them are secondaryly deposited and produced in the form of gravel. In addition, there are stratification as a feature of lithology and lithology, and there are various names as raw material resources such as diatomaceous earth, diatomaceous mudstone, shale, siliceous shale, and hard shale. (See Non-Patent Document 1 and Non-Patent Document 2)

  Japanese Patent No. 2652593   Patent No. 2964393   Japanese Patent No. 3659867

  "Research on Advanced Utilization and Resource Evaluation of Hondo Diatomaceous Earth", 1992 Joint Research Report, Hokkaido Prefectural Industrial Experiment Station, Resource Research Laboratory under Hokkaido Location, March 1993   "Research on advanced utilization and resource evaluation of main road diatomaceous earth", 1994 joint research report, Hokkaido Prefectural Industrial Experiment Station, Hokkaido Resources Research Laboratory, March 1995

  Conventional MPCs using mesopore-type diatomaceous earth have low whiteness, and in oxidation firing, the color of iron contained therein gives a red-brown color tone. In order to suppress the color development of iron, the method of blending another ceramic raw material with a low iron content decreases the function of mesopores, which is a feature of MPC, and impairs the original purpose.

  The inventor of the present application can be whitened by the technique described in “Method for producing thermal acid-treated alumina and method for producing white ceramic using this thermal acid-treated alumina” (Japanese Patent No. 2754347). A hot acid-treated alumina having a function cannot be manufactured at low cost.

  Japanese Patent No. 2754347

  The method of decorating a molded article such as a tile with a glaze or makeup soil has a problem that the function is lowered when the strength of the decoration part is increased, but the granular product cannot be whitened or decorated.

  Although there is a method of dissolving and removing the iron content contained in mesopore diatomaceous earth with a hot acid or the like, it is expensive, and environmental pollution due to drainage is also a problem.

  As a ceramic technique, there is a technique in which a reducing agent is added to mesopore diatomaceous earth and baked at a high temperature to whiten the iron component into a ferrous state, but the function of mesopore is lost by sintering.

  The purpose of the present invention, which has been made in view of the above-mentioned problems of the prior art, is to diversify the design of MPC and expand its use as an environmental material for living, thereby creating a durable and long-lasting house, as well as healthy and comfortable It is intended to contribute to comfortable living.

Means for solving the problem

  In order to achieve the above object, the present invention is characterized in that it is produced at low cost by firing at 600 to 1000 ° C. in an oxidizing atmosphere using mesopore diatomaceous earth produced from Mebetsu, Wakkanai City.

  Mesopore diatomite here is a natural mineral of diatom origin characterized by porosity, with mesopores with a pore size of 2 to 50 nm in diameter, and its lithology, lithology, and state of occurrence. Does not matter.

  The stratum in which the mesopore diatomaceous earth used in the present invention is presumed is the Wakkanai Formation, but is formed by a special geological diagenesis. That is, due to the diagenesis under strong reduction, the iron content in diatomaceous earth is eluted as iron ions, and the iron content is extremely reduced.

  Near the surface, it is mudstone-like due to weathering, but the mesopore diatomaceous earth is hard and is produced in a lamellar quartzite form.

  In the scanning electron micrograph of this mesopore diatomite, like the Wakkanai layer diatomite described in Japanese Patent No. 2565593, diatom fossils are not clearly recognized, and fine particles newly crystallized by dissolution are observed. The

  The rock color of this mesopore diatomaceous earth is gray or black, but because it is carbonized under strong reduction, the organic matter contained in it is lost by firing under specified conditions and easily whitened. can do.

  The present invention uses mesopore diatomaceous earth produced in Mebetsu, Wakkanai city, pulverized and classified into a predetermined particle size, or processed into a gravel shape and produced by oxidation firing at 600 to 1000 ° C. MPC.

  The present invention pulverizes and classifies Mesopore diatomaceous earth produced in Wakkanai-Menbetsu into a predetermined particle size, and forms it into an arbitrary shape using a base material alone or with other ceramic raw materials, and is produced by oxidation firing at 600 to 1000 ° C. It is MPC characterized by doing.

Effect of the invention

  As described above, the MPC of the present invention can be easily produced by a ceramic method, and since it has high whiteness, it has excellent design and can be decorated in various colors. Therefore, since it can be used in various ways as a design material having a mesopore function, it contributes to the expansion of MPC applications, and its industrial significance is great.

  MPC is known for its ability to purify air, such as humidity conditioning, oil mist adsorption, adsorption of harmful volatile chemicals, and deodorization, as well as the function of purifying contaminated water from heavy metals. The role is growing and is attracting attention as a decontamination material for radioactive substances. The present invention is also significant in terms of stimulating scientific and technological curiosity for mesoporous materials.

Color system chromaticity by calcination temperature of diatomaceous earth powder from Wanbuchi City Moisture absorption and desorption characteristics of diatomaceous earth powder produced in Wakkanai, Japan Color system chromaticity according to the firing temperature of MPC molded from diatomite alone from Wanbuchi City Moisture absorption and desorption characteristics by firing temperature of MPC molded from diatomaceous earth alone from Wanbuchi City Color system chromaticity according to the firing temperature of the substrate MPC containing diatomaceous earth and Sasame clay produced in Meribetsu, Wakkanai Moisture absorption and desorption characteristics according to the firing temperature of the substrate MPC containing diatomaceous earth and Sasame clay from Mebetsu, Wakkanai Color system chromaticity of 4 kinds of ready-made MPC tiles

  Examples of the present invention will be described below.

In Example 1, the test was performed using the powdered or gravel white MPC according to claim 1 of the present invention as a sample. Hereinafter, the sample will be described.
Mesopore diatomaceous earth produced in Wakkanai, Mashibetsu, was pulverized and classified to a particle size of 0.15 mm or less, and non-fired powder and oxidized and fired powdery MPC at 400 to 1000 ° C. were produced. The result of having measured the chromaticity of the non-fired MPC and the fired body in the firing temperature range of 400 to 1000 ° C. is shown in FIG.

Hereinafter, a method for measuring chromaticity will be described.
Using a color difference meter CR-410 manufactured by Konica Minolta, L *, a *, and b * that are the color system chromaticities of the sample are measured. The L * value (0 to 100) is a value representing whiteness, and the greater the whiteness, the higher the whiteness. The a * value is a value (0 to 60) representing redness, the b * value is a value (0 to 60) representing yellowness, and in order to obtain a clear whiteness, the a * value and the b * value It is desirable that the absolute value is smaller.

  In FIG. 1, the non-fired L * value is 67.1 and is gray, but the L * value exceeds 80 at a firing temperature of 600 ° C. or higher, and is very high at 87.5 at 1000 ° C.

On the other hand, the a * value indicating the redness is 2.6 to 3.2 at 600 ° C. or higher, maintains a low numerical value, and has little fluctuation due to the baking temperature.
Moreover, b * value which shows yellowness is 6.3-8.6 above 600 degreeC baking, a low numerical value is maintained and the fluctuation | variation by baking is small like red degree.

  The result of measuring the moisture absorption / release function for the same sample as above is shown in FIG.

Hereinafter, a method for measuring the moisture absorption / release function will be described.
The temperature inside the tank is kept constant using a thermo-hygrostat, the relative humidity is changed every 24 hours, the moisture absorption rate of the sample is measured, and the difference is defined as the moisture absorption / release function. The temperature in the tank was 20 ° C., and the humidity range to be varied was 50% RH on the low humidity side and 90% RH on the high humidity side, but the greater the moisture absorption / release function, the greater the humidity control effect.
In FIG. 2, the 50% RH 24-hour moisture absorption rate and the 90% RH 24-hour moisture absorption rate tend to decrease as the firing temperature rises in the range of the firing temperature of 400 to 1000 ° C., and the moisture absorption / release moisture represented by the difference therebetween. The function is 9.6 wt. %, At 500 ° C., 9.4 wt. %, At 1000 ° C., 3.2 wt. %, And tends to decrease as the firing temperature increases. The moisture absorption / release function in the case of non-firing is 10.3 wt. %, And the moisture absorption / release function is greater than in the case of firing.

From the above, the moisture absorption / release function and the firing temperature have a negative correlation, and the moisture absorption / release function decreases as the firing temperature increases, but the degree of decrease is small, and even at 1000 ° C firing, it is practical as a humidity control material. 3.0 wt. % Or more.
In addition, it is known that the strength and the firing temperature have a positive correlation in the ceramic characteristics of mesopore diatomaceous earth, and the higher the firing temperature, the larger the particle strength. Therefore, it is easy to pulverize and classify Mesopore diatomite from Mebetsu, Wakkanai, based on the target material design, and then pulverize and classify it, or pulverize and classify after firing. Can be produced.

In Example 2 and Example 3, the test was performed using the white MPC molded body according to claim 2 of the present invention as a sample. Hereinafter, the sample will be described.
After pulverizing and classifying Mesopore diatomaceous earth produced in Wakkanai-shi Meribetsu to a particle size of 0.15 mm or less, and forming it alone into a disk shape with a diameter of 50 mm and a thickness of 10 mm, the whiteness of MPC oxidized and fired at 400 to 1000 ° C. FIG. 3 shows the moisture absorption / release function.
The whiteness is increased from 500 ° C., and the L * value is 80 or more at 600 ° C. or more. The moisture absorbing / releasing function, which is a feature of MPC, decreases as the firing temperature increases, but even at 1000 ° C., 3.0 wt. % And has a practical function.

In addition, it is made of a base material that is made by mixing diatomaceous earth produced in Wakkanai-shi Meribetsu, with a particle size of 0.15 mm or less, and a common ceramic material, Sasame Clay, in a disk shape with a diameter of 50 and a thickness of 10 mm. FIG. 5 shows the chromaticity of MPC oxidized and fired at 400 to 1000 ° C. after molding, and FIG. 6 shows the moisture absorption / release function.
Similar to MPC prepared with diatomaceous earth alone, L * value representing whiteness becomes 80 or more when calcined at 600 ° C. or higher. Even with MPC calcined at 1000 ° C., the moisture absorption / release function peculiar to mesopores is 3.2 wt. % And has a practical function.

After pulverizing diatomaceous earth produced in Mebetsu, Wakkanai, to a particle size of 0.15 mm or less, it was oxidized and fired at 800 ° C. to prepare a powdered MPC. To 100 parts of the MPC powder, 3 parts of natural glue and 3 parts of recycled recycled paper pulp were added and premixed, and kneaded with water to prepare a paste-like coating material. The coating material was applied smoothly to a plaster board with a thickness of about 2 mm using a plastering jar.
After drying, the chromaticity was measured, only the coating material was peeled off, and the moisture absorption / release function was measured. The L * value representing whiteness is 89.4, and the moisture absorption / release function is 7.2 wt. %, And a whiteness such as titanium oxide is high, and the coating material exhibits high mesopore-specific functions.

Hereinafter, a comparative example will be described.
FIG. 7 shows the chromaticity of four types of MPC tile ready-made products that have been used conventionally.
Each sample has a low whiteness L * value as low as around 70, a redness a * value of 10 or more, and a yellowness b * value of 20 or more, both of which are high.

Claims (2)

  Powdered or gravel-like mesoporous ceramics with a whiteness of 80 or more, produced by oxidation firing at 600 to 1000 ° C. using diatomaceous earth produced in Wakkanai, Japan.   A mesoporous material with a whiteness of 80 or more, characterized by pulverizing diatomaceous earth produced in Wakkanai, Mashibetsu, and combining it with other ceramic raw materials to form an arbitrary shape, followed by oxidation firing at 600 to 1000 ° C. Ceramics.

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