JPH02302588A - Glazing furnace - Google Patents

Abstract

PURPOSE:To reduce generation of fiber chips by coating the surface of a ceramic fiber lined on the inner wall of a furnace with compound containing alkaline metal or alkaline earth metal. CONSTITUTION:Ceramic fiber lined on the inner wall of a furnace is coated with compound containing alkaline metal or alkaline earth metal. The ceramic fiber includes, for example, ceramic fiber product used heretofore as a liner of the inner wall of a furnace such as fiber block, fiber blanket, fiberboard, etc. The surface of such ceramic fiber is coated at least with compound containing alkaline metal or alkaline earth metal such as electrolyte salt of Ca, Na, I, Mg, etc. Thus, even if the surface of the fiber is cured, or fibers are entangled, thermally expanded, shrinked by cooling or circulated in the furnace by a burner, fiber chips are not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a glazed product firing furnace suitable for firing glazed ceramic products such as sanitary ware.

(Prior Art) As a furnace for firing glazed ceramic products, a firing furnace whose inner wall is made of refractory bricks is generally used. However, such furnaces have a large heat capacity and insufficient heat insulation, so they have the drawback of extremely poor fuel efficiency, especially in the case of window type furnaces such as shuttle kilns.

On the other hand, in recent years, many furnaces have been put into practical use where the furnace material has been changed from the conventional refractory bricks to ceramic fibers. This type of furnace has a small heat capacity and an excellent insulation effect, resulting in a significant improvement in fuel efficiency, especially in the case of a shuttle kiln, which has a window type furnace that frequently raises and lowers the temperature. However, this type of furnace suffers from 100% of the ceramic fiber surface due to thermal expansion during temperature rise and fall, cooling contraction, circulation flow of combustion gas in the furnace, etc.
Fiber fragments of ~500μ are generated and adhere to the surface of glazed products, resulting in many product defects.For example, in a furnace whose inner wall is made of ceramic board, thermal expansion, cooling When the boards were rubbed together due to shrinkage, fibers were generated that became fiber rags, and these fibers were peeled off from the board surface by the circulating flow of combustion gas in the furnace, resulting in fiber rags. In addition, in furnaces whose inner walls are made of fiber blocks, there are a large amount of easily peeled fibers on the surface, and the circulating flow of combustion gas inside the furnace easily causes minute fiber pieces to peel off, resulting in fiber rag. .

As mentioned above, in ceramic fiber lined furnaces with excellent fuel efficiency, the occurrence of fiber rags is unavoidable, and it was considered unavoidable that some rags would occur during firing of glazed products. Therefore, when firing products such as sanitary ware that cannot tolerate crumbling defects, countermeasures have been considered, such as extending the firing time longer than necessary or covering the product with a lid during firing, but none of these methods work. This has the drawback of causing deterioration in fuel efficiency and productivity.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional drawbacks, and provides a ceramic fiber lining that has excellent fuel efficiency and can significantly reduce the occurrence of looseness during firing of glazed products. It was completed to provide a kiln for firing sushi glazed products.

(Means for Solving the Problems) The present invention for solving the above problems is characterized in that ceramic fibers lined on the inner wall of the furnace are coated with a compound containing at least an alkali metal or an alkaline earth metal. It is something to do.

Examples of the ceramic fiber used in the present invention include ceramic fiber products conventionally used as lining materials for the inner walls of furnaces, such as fiber blocks, fiber plan care, and fiber boards.

In the present invention, the surface of such a ceramic fiber is coated with a compound containing at least Ca + Na and an alkali metal or alkaline earth metal such as an electrolyte salt such as Mg. By hardening or entangling the fibers, fiber rags will not occur even when exposed to thermal expansion, cooling shrinkage, and furnace circulation by a burner.

Such coating may be performed with a water-soluble treatment agent or with a volatile treatment agent. In the case of water-soluble treatment materials, KOH, KISO4, zcOs, NaOH, Na
zSOa.

NatCOi, Ca(OH)t, CaSO4,Ca
Aqueous solutions of compounds containing alkali metals or alkaline earth metals, such as CO5, are used. The concentration of these compounds is adjusted to about 0.1 to 10% by weight, a water-soluble binder (for example, a 0.1 to 0.5% aqueous solution of organic glue) is added as necessary, and the inner wall of the furnace is lined. 0.1 to 101 on the surface of the ceramic fiber with a spray gun etc.
Spray at a rate of 7 m''.Before spraying, heat the inside of the furnace at 900°C or higher for at least 1 hour to remove any moisture adhering or adsorbing to the ceramic fibers. is preferable, and the angle after spraying is 80°.
Dry at 100'C to 100'C for 2 hours or more, and heat in an oxidizing atmosphere with a concentration of 0.5% or more at around 1000'C depending on the type of material to be treated.

On the other hand, in the case of using a volatile treatment material, a container with an open top containing the same treatment material as above, or ceramics glazed with a glaze containing the same treatment material as above, is placed in a furnace, and
Heat for 2 to 3 hours according to the volatilization temperature of the processing material of 0°C or higher. In this case as well, the inside of the furnace is kept in an oxidizing atmosphere with a concentration of 5% or more. In either case, the number of processing times depends on the product,
It shall be changed as appropriate depending on the type of treated material and ceramic fiber.

(Function) Since the furnace of the present invention configured as described above has an inner wall lined with ceramic fiber, the heat capacity of the conventional furnace body is small and the heat insulation effect is excellent, resulting in a significant reduction in fuel consumption. You can improve your performance. Moreover, since the furnace of the present invention coats the surface of the ceramic fiber with a compound containing at least an alkali metal or an alkaline earth metal, it is possible to harden the surface of the fiber or cause entanglement of the fiber. I can do it. Therefore, the furnace of the present invention can improve fuel efficiency and prevent the occurrence of fiber rag.

Next, examples of the present invention will be shown.

(Example) Example 1 Using an experimental furnace with an internal volume of 5,001 cm and whose inner walls were lined with ceramic fiberboard, six 150 x 150 glazed tiles were fired at a maximum temperature of 1,300°C. An average of 30 fiber rags were confirmed per sheet.

Therefore, 4% by weight of a glaze in which the main components of alkali metal and alkaline earth metal compounds are KxCOs and Ca(OH)t.
The aqueous solution was sprayed onto the surface of the ceramic fiberboard and dried at 80''C to 100℃ for over 2 hours as described above.Then, when the glazed tiles were fired in the same manner as above, no fiber boro was generated. .

Example 2 Six 150 x 150 m glazed tiles were fired at a maximum temperature of 1250°C using an experimental furnace with an internal volume of 5RYF whose inner walls were lined with ceramic fiberboard, and fine fibers were observed on the tile surface. 20 to 30 rags were confirmed per sheet.

Therefore, when we sprayed a 7% by weight aqueous solution of glaze whose main component was KmCOs onto the surface of the ceramic fiberboard, and further treated it with the above-mentioned volatile treatment material whose main component was KmCO3, the occurrence of fiber rag on the tile surface was eliminated. 1
The number has decreased to 1 to 2 pieces per sheet.

(Effects of the Invention) As is clear from the above description, the present invention prevents the occurrence of fiber boro by coating the surface of ceramic fibers lined on the inner wall of a furnace with a compound containing at least an alkali metal or an alkaline earth metal. As a result, it is possible to obtain excellent fuel efficiency and to significantly reduce the occurrence of sagging defects during firing of glazed products. Therefore, the present invention has extremely great practical value as it eliminates the drawbacks of this type of conventional glazed product firing furnace.

Claims (1)

[Claims] A glazed product firing furnace characterized in that ceramic fibers lined on the inner wall of the furnace are coated with a compound containing at least an alkali metal or an alkaline earth metal.