JP2754347B2 - Method for producing hot-acid-treated alumina and method for producing white ceramics using this hot-acid-treated alumina - 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 thermally acid-treated alumina and a method for producing white ceramics using the thermally acid-treated alumina. In particular, the latter relates to a method for producing white ceramics without removing iron using a low-grade raw material containing iron. Details are as follows. Japan was one of the leading ceramic raw material nations, but high-quality raw materials with low iron content have been gradually depleted and become increasingly dependent on overseas. On the other hand, a large variety of low-grade raw materials containing iron are present in Hokkaido and the like, which occupies about 22% of the total area of Japan. Conventionally, high quality of low-grade raw materials containing iron has been carried out by a method of removing iron by a physical or chemical method. However, it is extremely difficult to remove iron particularly from clay minerals. In addition, this method requires a high raw material cost and cannot be used for building ceramics and the like. The present invention is a method for suppressing the coloring of ceramics due to the contained iron and whitening the mixture by adding a functional alumina which has been subjected to a thermal acid treatment without removing the iron from the raw material. Alumina for whitening can be easily produced by thermal acid treatment, and various kinds of alumina such as alumina which has become industrial waste can be used. Therefore, the white porcelain can be easily manufactured without using expensive high-quality raw materials, so that the use thereof is extremely wide.

[0002]

2. Description of the Related Art Conventionally, the following techniques have been known for this type. 1. Production method of activated alumina as functional alumina The aluminum hydroxide is heat treated at a temperature of 300-900 ° C. before transferring to stable alpha alumina. Thereby, characteristics such as adsorptivity are imparted. 2. Manufacturing method of white ceramics Iron is removed from raw materials by physical and chemical methods. B. Chlorine gas is introduced during the firing process to react with iron and volatilize. C. Utilizes synthetic raw materials such as artificial kaolin.

[0003]

The above-mentioned prior art has the following problems. 1. Production method of functional alumina Alumina obtained by a conventional production method does not have a function of suppressing color development due to iron. 2. Manufacturing method of white ceramics The process of removing and purifying iron from the raw material is costly and expensive. At present, removal of iron contained in clay minerals and the like in raw materials has not been established yet. B. Introducing chlorine gas during the firing process is not practical, even if possible on a laboratory scale. Further, chlorine gas is toxic and toxic, and is dangerous and problematic from an environmental point of view. C. Synthetic raw materials are expensive and cannot be used for general building ceramics.

[0004] The present application has been made in view of such problems of the prior art, and has as its object to provide the following. 1. Manufacturing Method of Functional Alumina By subjecting alumina to thermal acid treatment and blending it with a ceramic material to produce a ceramic, a function of suppressing color development due to iron contained in the ceramic material can be imparted. 2. Manufacturing method of white ceramics The present invention has solved the above-mentioned problems by providing white ceramics at a low cost without removing iron from a variety of low-grade raw materials containing iron.

[0005]

Means for Solving the Problems In order to achieve the above object, the present invention is as follows. The first invention is a method for producing thermally acid-treated alumina comprising the following first to eighth steps. First step-The spent catalyst carrier alumina is pulverized by a pulverizing device such as a ball mill so that the particle size becomes 30 mesh or less. Step 2-Using an acid-resistant and heat-resistant container, hydrochloric acid having a concentration of 1N or more is added to the pulverized product and mixed at least until a slurry is obtained. Third step-heating with stirring by a stirrer. Fourth step: The slurry state is separated into a liquid and a solid by a filter. Fifth step-The solid in the wet state, which has been filtered and separated, is re-introduced into the vessel in order to remove the residual hydrochloric acid, and water is added thereto, followed by washing with stirring. Filtration and separation are performed in the same manner as in the sixth to fourth steps. Step 7-The wet solid is placed in a flat heat-resistant container or the like, and the water is evaporated to dryness. Eighth step-The dried solid is pulverized with a pulverizing device such as a ball mill to adjust the particle size to, for example, 100 mesh or less.

A second invention is to produce a thermally acid-treated alumina by the production method of the first invention, and to blend this thermally-acid-treated alumina with an iron-containing low-grade raw material such as clay.
A method for producing a white ceramic using hot-acid-treated alumina, characterized in that the obtained compound is used as a material of a molding base soil to produce a white ceramic without removing iron from the iron-containing low-grade raw material. is there. In this case, the second invention is
It can be as follows. In other words, low-grade iron-containing raw materials such as soapy clay (1) Wakkanai siliceous shale from Tomicho, (2) Nopporo clay from Ebetsu, (3) Kagura clay from Asahikawa, and (4) Kenbu from Kenbuchi A white porcelain can be manufactured by the following manufacturing process using one selected from Fuchi clay. And iron-containing low-grade material, such as stoneware clay selected from the first step to the (1) to (4), as a material of the forming material earth only thermal acid treated alumina produced by the production method of the first invention, Al ₂ Compounding so that the molar ratio between O ₃ and SiO ₂ is mullite (Al ₂ O ₃ : SiO ₂ = 3: 2). The mixture obtained in the second step to the first step is pulverized and mixed, and the water content is adjusted to adjust the molding base soil.
Press molding or clay molding using the molding base soil obtained in the third step and the second step. After drying the molded product obtained in the fourth step to the third step, firing at 900 ° C. or more.

[0007]

[Action] The action will be described together with the effect.

[0008]

An embodiment will be described with reference to the drawings. The method for producing the thermal acid-treated alumina of the first invention is configured as follows with reference to FIG. 1st step-1 particle size of waste catalyst carrier alumina is 30 mesh
Pulverize with a pulverizing device such as a ball mill as follows. Second step-Use an acid-resistant, heat-resistant container (for example, an iron pot-type container provided with a lining or coating of rubber, Teflon, or the like), and add hydrochloric acid having a concentration of 1N or more to the pulverized material to at least. And mix until a slurry is obtained. In this case, mineral acids other than hydrochloric acid, such as nitric acid and sulfuric acid, can be used in place of or in combination. Third step-heating is performed by a method of directly blowing steam while stirring with a stirrer. However, an indirect heating method in which the container is heated from the outside or a method using an exothermic reaction (such as water dilution heat) may be used. The heating temperature is preferably 60 ° C. or higher, and the stirring time is preferably 1 hour or longer.

Fourth step: The slurry state is separated into a liquid and a solid by a filter such as a filter press. Fifth step: In order to remove the residual hydrochloric acid, the wet solid separated by filtration and separation is re-introduced into the vessel, and water is added thereto, followed by washing with stirring. At this time, a small amount of alkali such as sodium hydroxide may be added to neutralize the residual hydrochloric acid. Filtration and separation are performed in the same manner as in the sixth to fourth steps. Step 7-The wet solid is placed in a flat heat-resistant container or the like, and the water is evaporated and dried at a temperature of 100 ° C. or more using a hot-air dryer or the like. Eighth step-The dried solid is pulverized with a pulverizing device such as a ball mill to adjust the particle size to, for example, 100 mesh or less.

The second invention is configured as follows. The following is an example of producing a ceramic humidified tile having high whiteness using the Wakkanai siliceous shale excellent in humidity control function as a raw material. The chemical composition of the Wakkanai siliceous shale used is shown in Table 1. The iron content is 3.1 wt% as Fe ₂ O ₃ .

[0011]

[Table 1]

The mineral composition is shown in the X-ray diffraction chart of FIG. Table 2 shows the chemical composition and the main form of alumina mixed with the Wakkanai siliceous shale.

[0013]

[Table 2]

NO. 1 Al ₂ O ₃ is alumina used as a catalyst carrier for automobiles.
What was calcined at 0 ° C was NO. 2 Al ₂ O ₃ . NO. 3 Al ₂
O ₃ is a catalyst carrier alumina to be discarded, and the residue alumina obtained by recovering the catalyst by hot acid treatment and calcined at 600 ° C. is NO. 4 Al ₂ O ₃ . NO. 5 Al ₂ O ₃ is high-purity alumina manufactured by Nikko Kin Co., Ltd.
What was calcined at 0 ° C was NO. 6 Al ₂ O ₃ .

FIGS. 2 to 4 show NO. Shows an X-ray diffraction chart of the Al ₂ O ₃ of 1, 4, 5. Using the above Wakkanai siliceous shale and alumina raw materials, mixing and crushing at the mixing ratio shown in Table 3,
M-1 to 6 tile bases were prepared. Mixing and pulverization were performed by a wet method using a porcelain ball mill.

[0016]

[Table 3]

After preparing each tile base material to have an appropriate moisture and particle size, it is press-formed at a pressure of about 200 kgf / cm ² , dried, and then dried in an electric furnace to 900, 1000, 1100.
It was calcined in three stages of ° C. The firing rate is 200 ° C.
/ H, and kept at a predetermined temperature for 1 hour, and then allowed to cool naturally in a furnace. Table 4 shows the whiteness by firing temperature for each tile base, and for M-4, the moisture absorption / release function and bending strength are also shown.

[0018]

[Table 4]

The moisture absorption / desorption function is as follows: the temperature in the chamber is set to 25 ° C. using a thermo-hygrostat, the humidity is changed to 90% and 50% every 24 hours, and the moisture absorption rate of the sample at each humidity is measured. The difference was obtained and indicated by an absolute value.

FIG. 5 shows the firing temperature and whiteness of each tile. The whiteness of any of the aluminas used is greatly improved by the thermal acid treatment. Next, an example of the implementation of a combination base material of Nopporo clay in Ebetsu, which is known as a representative stoneware clay in Hokkaido, and Kagura clay and alumina in Asahikawa, is shown. It is known that each of the clays contains about 3% by weight of iron. However, four types of compound bases shown in Table 5 were prepared, and tiles were prepared.

[0021]

[Table 5]

The steps for manufacturing the tile are the same as those described above. FIG. 6 shows the firing temperature and whiteness of each tile. 5 Waste N than using Al ₂ O ₃
O. 4 A tile with higher whiteness can be obtained by baking at 1000 ° C. or higher with Al ₂ O ₃ .

[0023]

Since the present invention is configured as described above, the following effects can be obtained. 1. Production method of thermal acid-treated alumina By the thermal acid treatment, a function of suppressing color development due to iron which is not present in conventional functional alumina can be provided. B. With this basic manufacturing method, development of a wide variety of functional alumina can be expected.

2. Manufacturing method of white ceramics Since white ceramics can be easily produced by adding thermal acid-treated alumina without removing iron from low-grade raw materials, various raw materials such as ceramic clay can be used as white ceramic raw materials. This expands the use of local resources and can contribute to the development of local industries. B. Since the thermal acid-treated alumina having such a function can be produced using various kinds of alumina as a starting material, it contributes to reuse and recycling of industrial waste such as waste catalyst carrier alumina. C. Since the thermally acid-treated alumina is considered to be a lattice defect alumina, it can be expected to have various uses as a functional alumina such as an adsorption ability.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction chart of the Wakkanai siliceous shale.

FIG. 2 is an X-ray diffraction chart of unused catalyst carrier alumina.

FIG. 3 is an X-ray diffraction chart of alumina sludge as a catalyst recovery residue.

FIG. 4 is an X-ray diffraction chart of alumina (A-32) manufactured by Nikkei Kin Co., Ltd.

FIG. 5 shows Table 4 graphically.

FIG. 6 shows Hunter-type whiteness of tiles at different firing temperatures prepared from a mixture of clay and alumina.

FIG. 7 is a manufacturing process diagram of the thermally acid-treated alumina.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C04B 35/10 B09B 3/00 304L

Claims (3)

(57) [Claims] 1. A method for producing thermally acid-treated alumina, comprising the following first to eighth steps: First step-The spent catalyst carrier alumina is pulverized by a pulverizing device such as a ball mill so that the particle size becomes 30 mesh or less. Step 2-Using an acid-resistant and heat-resistant container, hydrochloric acid having a concentration of 1N or more is added to the pulverized product and mixed at least until a slurry is obtained. Third step-heating with stirring by a stirrer. Fourth step: The slurry state is separated into a liquid and a solid by a filter. Fifth step: In order to remove the residual hydrochloric acid, the wet solid separated by filtration and separation is re-introduced into the vessel, and water is added thereto, followed by washing with stirring. Filtration and separation are performed in the same manner as in the sixth to fourth steps. Step 7-The wet solid is placed in a flat heat-resistant container or the like, and the water is evaporated to dryness. Eighth step-The dried solid is pulverized with a pulverizing device such as a ball mill to adjust the particle size to, for example, 100 mesh or less. 2. A hot acid-treated alumina is produced by the production method according to claim 1, and the hot acid-treated alumina is blended with a low-grade raw material containing iron, such as a cementitious glue, and the resulting blend is formed. A method for producing white ceramics using thermally acid-treated alumina, characterized by producing white ceramics without removing iron from the iron-containing low-grade raw material as a material of the base soil. 3. Low-grade raw materials containing iron, such as clayey clay, (1) Wakkanai Formation siliceous shale from Tomimachi, (2) Nopporo clay from Ebetsu, (3) Kagura clay from Asahikawa, and (4) Kenbuchi The method for producing white ceramics according to claim 2, wherein white ceramics are manufactured by the following manufacturing process using a material selected from town-produced Kenbuchi clay. Only the iron-containing low-grade raw materials such as the clayey clay selected from the first step to (1) to (4) and the hot-acid-treated alumina produced by the production method according to claim 1 are used as the material of the molding base material. The molar ratio of Al ₂ O ₃ to SiO ₂ is mullite (Al ₂ O ₃ : SiO ₂ = 3: 2). The mixture obtained in the second step to the first step is pulverized and mixed, and the water content is adjusted to adjust the molding base soil. Press molding or clay molding using the molding base soil obtained in the third step and the second step. 4th process-3rd
After drying the molded product obtained in the step, baking at 900 ° C. or more.