JP3202972B2 - Dry manufacturing method of ceramic fiber board - 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 a board containing ceramic fibers as a main component, in particular, a ceramic fiber board having a relatively low density and excellent heat insulation, nonflammability and wind resistance.

[0002]

2. Description of the Related Art Conventionally, ceramic fiber boards mainly composed of ceramic fibers such as alumina and mullite have been used as lining materials and building materials for various heating furnaces.

[0003] The manufacture of such ceramic fiber boards is generally performed by a wet method. That is, the defibrated ceramic fiber is dispersed in water together with an inorganic binder such as colloidal silica or alumina sol, and an organic coagulant is added for coagulation, formed into a board shape by vacuum suction or the like, and then dried and dried if necessary. The ceramic fiber board is manufactured by firing.

As a method for producing a board by a dry method, for example, as described in Japanese Patent Application Laid-Open No. Sho 62-130802, mineral fibers such as rock wool are mixed with a powdery resin such as a novolak type phenol resin in a defibrating machine. Supply,
A method is known in which defibrated fibers mixed with a powdered resin are formed into a mat shape and then molded by hot pressing.

[0005]

The above-mentioned wet method, which is a general method for manufacturing a ceramic fiber board, involves a large number of steps including a drying step due to wet molding, which leads to an increase in cost and a reduction in mass productivity. Also had the disadvantage of being inferior. Further, an organic binder is usually used to prevent migration of the inorganic binder. However, when this organic binder is used as a material for furnace lining, there is a problem that it burns at a high temperature and emits smoke.

[0006] On the other hand, the above-mentioned dry method has a smaller number of steps than the wet method and is relatively simple. However, since powdered resin is used for bonding the fibers, there remains a problem of burning at a high temperature and generating smoke. In addition, by using a powdered resin, a high-density and high-strength board can be obtained by increasing the amount of the binder to be added, but it is difficult to manufacture a low-density board.

[0007] Further, in these conventional methods for manufacturing a ceramic fiber board, the bulk of a ceramic fiber provided as a primary product is used as a raw material, which is defibrated and a board is manufactured as a secondary product by a wet or dry method. However, there is no known method for obtaining a ceramic fiber board as a primary product.

Further, ceramic fiber boards are desired to be reduced in weight as furnace lining materials and building materials, but the bulk density of ceramic fiber boards obtained by a wet method is 0.2 to 0.7 g / cm ^3. Therefore, a ceramic fiber board having a lower density is also required.

The present invention has been made in view of such conventional circumstances,
Provides a simple and mass-produced method for producing ceramic fiber boards that does not use organic binders and therefore does not cause smoke problems, and enables lower density ceramic fiber boards to be obtained as primary products. The purpose is to do.

[0010]

In order to achieve the above object, a method of manufacturing a ceramic fiber board provided by the present invention is based on a dry method, wherein a raw material of a ceramic fiber is fiberized while an inorganic boron compound is formed. The powder is uniformly added and mixed, and the obtained ceramic fiber is formed into a plate shape by needling or the like, and a dispersion containing the inorganic silicon compound is added to both surfaces of the ceramic fiber.
Addition of silica to 1 kg of ceramic fiber
After spraying to be 10 to 50 g in total , 800 ° C
It is characterized by firing at the above temperature, and even inside
Ceramic fins that are hardened at the same time and have relatively high surface hardness
Bar board is obtained.

As the ceramic fiber, alumina, alumina / silica or mullite ceramic fiber is preferable, but rock wool, glass wool or the like can also be used. Further, boric anhydride, boric acid, boron nitride and the like can be used as the inorganic boron compound, and silica is preferable as the inorganic silicon compound.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention utilizes a conventional manufacturing process of a ceramic fiber (bulk) or a blanket of a ceramic fiber, and a ceramic fiber cured entirely by a dry method. A board is manufactured.

The dry manufacturing method of the ceramic fiber board according to the present invention will be described with reference to the flowchart shown in FIG. First, according to a normal fiberizing process, a ceramic fiber raw material comprising alumina, silica, a predetermined additive, and the like is electrically melted in a melting furnace, and the molten raw material is fiberized by a blowing method in which a high-speed gas flow is blown. . The fiberization process itself is the same as the normal ceramic fiber (bulk) manufacturing process, and there is no difference from the ceramic fiber manufacturing process incorporated in the blanket manufacturing line.

In the present invention, in the above-mentioned fiberizing step,
A powder of an inorganic boron compound is added and supplied to a ceramic fiber obtained continuously. The inorganic boron compound powder is
What is necessary is just to supply until the ceramic fiber obtained by blowing of gas accumulates in the cotton collection room, for example,
The inorganic boron compound powder is supplied into a gas such as compressed air blown to the molten raw material, or the inorganic boron compound powder is added and supplied into the flow of ceramic fibers in the cotton collecting chamber. Thereby, the inorganic boron compound powder can be uniformly mixed in the ceramic fibers accumulated in the cotton collecting chamber.

The amount of the inorganic boron compound to be added is 10 to 3 in terms of boron per 1 kg of the ceramic fiber.
It is preferred to be in the range of 0 g. If the amount of the inorganic boron compound is less than 10 g / kg, the obtained ceramic fiber board cannot be uniformly cured to the inside. On the other hand, if the amount exceeds 30 g / kg, economical efficiency is deteriorated and shrinkage after heating increases.

The obtained ceramic fiber is formed into a plate shape by means such as needling or rollers used for manufacturing a blanket. Generally, it is compressed by a roller provided at the outlet of the cotton collecting chamber, and is further formed into a plate having a predetermined thickness by needling. In particular, needling has the advantage that the scattering of the ceramic fiber and the collapse of the shape can be prevented, and the blanket manufacturing apparatus can be used as it is. The punch density in needling is not particularly limited, but is preferably about 3 to 20 punches / cm ² .

Next, a dispersion liquid containing an inorganic silicon compound such as silica is sprayed on both surfaces of the ceramic fiber formed into a plate shape. By adding the inorganic silicon compound to the surface, sufficient surface hardening is achieved by the calcination described below, and the handleability of the obtained ceramic fiber board is improved. Further, the reason why the inorganic silicon compound is added after the molding of the ceramic fiber is that if it is added before the molding, the ceramic fiber solidifies and molding by needling or the like becomes difficult. A dispersion obtained by dispersing colloidal silica in water can be suitably used as the dispersion. In addition, this dispersion may contain an inorganic boron compound such as boric anhydride described above in addition to the inorganic silicon compound.

The amount of the inorganic silicon compound added by spraying is
In the case of the inorganic silicon compound alone, the range is preferably 10 to 50 g in terms of silica with respect to 1 kg of the ceramic fiber. When the dispersion contains an inorganic silicon compound and an inorganic boron compound, the amount is preferably about 10 to 50 g per 1 kg of the ceramic fiber. If the amount of each addition is less than each of the above lower limits, the surface portion of the ceramic fiber board obtained cannot be sufficiently cured, and if it exceeds each of the above upper limits, the economic efficiency is poor and the surface portion is easily peeled off. is there.
The concentration of the inorganic silicon compound and the inorganic boron compound in the dispersion is preferably about 10 to 100 g / l in total.

After spraying the dispersion of the inorganic silicon compound,
By firing the ceramic fibers at a temperature of 800 ° C. or higher, a ceramic fiber board is obtained in which the ceramic fibers are bonded together and hardened as a whole. In this firing step, it is preferable to perform the first-stage firing at 800 to 1100 ° C. and then further perform the second-stage firing at 1200 to 1300 ° C. The baking time is about 3 to 30 minutes for the first baking and about 30 to 60 minutes for the second baking. In this firing step, firing can be performed while adjusting the thickness by pressing both surfaces of the ceramic fiber with press rollers.

By the firing, the inorganic boron compound and silicon which is a component of the ceramic fiber react inside, and the inorganic silicon compound further reacts with each other on the surface portion to form borosilicate glass. The ceramic fibers are bonded to each other by the borosilicate glass, uniformly hardened to the inside, and a ceramic fiber board having a relatively high surface hardness can be obtained.

That is, in the ceramic fiber board obtained by the method of the present invention, the ceramic fibers are bonded to each other by borosilicate glass, are uniformly hardened to the inside, have relatively high surface hardness, and have a bulk density of 0.1.
A ceramic fiber board having a relatively low density of about 5 to 0.3 g / cm ³ and having excellent heat insulating properties, nonflammability and wind speed resistance can be obtained.

As can be seen from the above description, the dry manufacturing method of the ceramic fiber board according to the present invention comprises the steps from the fiber raw material shown in the flowchart of FIG. It is almost the same as the manufacturing process of the fiber blanket. In this way, a normal blanket manufacturing apparatus can be used as it is, and only by supplying the inorganic boron compound and the inorganic silicon compound during the manufacturing process,
A ceramic fiber board completely different in properties from a flexible blanket, that is, uniformly hardened as a whole, can be easily manufactured as a primary product.

[0023]

EXAMPLE As shown in FIG. 2, a conventional ceramic fiber blanket production line is used, and an inorganic boron compound powder supply device and an inorganic silicon compound dispersion liquid spray device are arranged on the way. A ceramic fiber board was manufactured according to the method of the invention. The production line of the ceramic fiber blanket was set such that a blanket having a bulk density of 0.15 to 0.19 g / cm ³ and a thickness of 33 mm was obtained.

A ceramic fiber raw material containing alumina, silica and zirconia as main components is electrically melted in a melting furnace 2, and a high-speed stream of compressed air is blown onto the molten raw material 1 by a blowing method to continuously fibrillate. . B ₂ O ₃ powder was supplied in the course of the passage of the obtained ceramic fiber 3 to the cotton collection chamber 4, and was added to and mixed with the ceramic fiber 3. The addition amount of the B ₂ O ₃ powder was 4.2 kg with respect to 100 kg of the ceramic fiber.

A metal mesh conveyor 5a is provided at the bottom of the cotton collecting chamber 4, and conveys the accumulated ceramic fibers 3 to the outlet at a predetermined speed. A compression roller 5b is arranged at the outlet of the cotton collecting chamber 4, and compresses the ceramic fiber 3 to a predetermined thickness. Subsequently, the ceramic fiber 3 is supplied to the needle felter 6 by the conveying roller, and the punch density is 10 / c from both upper and lower sides.
By needling at m ² , it is formed into a thinner plate.

Next, a dispersion containing 30 g / l of B ₂ O ₃ and 15 g / l of SiO ₂ is uniformly sprayed on both surfaces of the plate-shaped ceramic fiber 3 using a spraying device 7. did. The spraying amount of the dispersion is 10
140 liters for 0 kg. Compounds can be included.

Ceramic fiber 3 sprayed with dispersion
Was supplied to a baking furnace 8 provided with a plurality of rollers 8a for setting the thickness and a heater 8b, and was baked at a temperature of 800 ° C. for 8 minutes while being compressed to a set thickness. Thereafter, the board 10 having a size of 625 mm × 625 mm is cut by the cutting device 9.
And baked at a temperature of 1300 ° C. for 40 minutes using a roller hearth kiln (not shown).

In the ceramic fiber board thus obtained, the ceramic fibers are bonded to each other by borosilicate glass and are uniformly cured to the inside, have a bulk density of 0.25 g / cm ³ , and have a surface hardness of 70 to 70%. 85
Degree. Further, the shrinkage after heating at 1200 ° C. for 8 hours was 0.1%, and the soaking loss was 0.0%.

[0029]

According to the present invention, by a simple dry method,
No organic binder is used, so there is no problem of smoke generation when used under heating, and the ceramic fiber board which has a relatively low density compared to the wet method, and has a hard surface and is uniformly hardened to the inside can be reduced. Can be manufactured at cost. In particular, in the production of a ceramic fiber board according to the method of the present invention, a ceramic fiber board can be obtained as a primary product by using an ordinary ceramic fiber blanket production line.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a method of manufacturing a ceramic fiber board according to the present invention in the order of steps.

FIG. 2 is a schematic explanatory view showing a production line for a ceramic fiber board used in an example of the present invention.

[Explanation of symbols]

1: melting raw material 2: melting furnace 3: ceramic fiber 4: cotton collection room 6: needle felter 7: spraying device 8: firing furnace 9: cutting device 10: board

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-266331 (JP, A) JP-A-5-32465 (JP, A) JP-B-49-10810 (JP, B1) (58) Field (Int.Cl. ⁷ , DB name) B28B 1/00-1/54 B28B 3/00-5/12 C03C 1/00-14/00 C04B 38/00-38/10

Claims (5)

(57) [Claims] 1. The method of claim 1 wherein the molten raw material of the ceramic fiber is a fiber.
The inorganic boron compound powderAdd and mix uniformly
Then, the obtained ceramic fiber is formed into a plate shape,
A dispersion containing an inorganic silicon compound on both surfaces ofInorganic silicon
Addition amount of compound per 1kg of ceramic fiber
So that it becomes 10 to 50 g in terms of silica.Sprayed
After that, firing at a temperature of 800 ° C. or more.
To, Evenly cured inside and relatively high surface hardnessC
Dry manufacturing method of lamic fiber board. 2. The method according to claim 1, wherein the ceramic fiber is formed into a plate shape by needling. 3. The dispersion according to claim 1, wherein the dispersion containing the inorganic silicon compound further contains an inorganic boron compound.
Or a method for dry-producing a ceramic fiber board according to item 2. 4. In the firing, 800 to 1100 ° C.
The method according to any one of claims 1 to 3, further comprising firing at 1200 to 1300 ° C after firing. 5. The ceramic fiber according to claim 1, wherein the inorganic boron compound is at least one of boron anhydride, boric acid, and boron nitride, and the inorganic silicon compound is silica. Dry manufacturing method of board.