JP5925025B2 - Functional ceramics and manufacturing method thereof - Google Patents

Description

  The present invention relates to a functional ceramic and a manufacturing method thereof.

(Functional ceramics)
Conventionally, there has been a demand for scientific explanation of functional ceramics, and to manufacture the ceramic so that its function can be expressed more reliably and strongly. For this purpose, non-stoichiometric metal oxides, noble metal fine particles, or magnetic compounds mainly composed of iron atoms, etc. are incorporated into ceramics by technological development that incorporates knowledge and knowledge from the latest science. Form and provide advanced features.

  There are many materials called functional ceramics, and they are used for ceramics that have catalytic functions, redox functions, electrical / magnetic functions, physical functions based on far-infrared radiation performance, and functions for living bodies. Examples of functions related to functional ceramics include chemical functions such as catalytic functions and redox functions and far-infrared radiation performance.

  In order for ceramics to exhibit chemical functions such as catalytic functions and redox functions, it is necessary to generate a large number of active sites such as basic sites with high electron donating properties and acid sites that accept electrons on the surface of ceramics. For these purposes, various metals are supported on the support surface of the ceramic catalyst. In particular, iron oxides that catalyze redox reactions, zirconium sulfate that forms super solid acids (Non-Patent Document 1), noble metal particulate catalysts (Non-Patent Document 2), and the like are said to exhibit high catalytic activity. .

  As functional ceramics, for example, a fired molded article having oxidation-reduction ability produced from limonite, clay and charcoal (Patent Document 1), functional ceramics comprising zeolite and soot for producing reduced water (Patent Document 2), A functional activated carbon ceramic made of zeolite and activated carbon that makes reduced water (Patent Document 3), a ceramic for reducing water disclosed in Granular Ceramics for Reduced Water and its production method (Patent Document 4), and tourmaline ore There are a water quality improver manufactured mainly, a water quality improver and a water quality improver of the method of using the same (Patent Document 5).

  Soil “Limonite” from Kyushu Aso, which is one of the soils containing high concentrations of iron oxide, utilizes its own redox ability, water purification material (Patent Document 6), deodorant (Patent Document 7) , A desulfurization apparatus (Patent Document 8), a calcined molded article having a redox ability produced from limonite, clay and charcoal (Patent Document 1). In addition to the functions derived from the redox ability of iron atoms, iron mixed in ceramics can form triiron tetroxide and become a magnetic material such as magnetite. Have.

  Ferric tetroxide and ferric oxide in ceramics are ferromagnets, so they are usually attracted to strong magnets, but non-stoichiometric iron oxides change their magnetism with temperature. There is also a phenomenon (Non-patent Document 3).

  In recent years, in the crystal structure of a magnetic material synthesized from a pure substance, frustration of electron spins of atoms constituting the crystal (Non-Patent Document 4), localization of electric charges occurs in the crystal structure of the magnetic material, It has been clarified that a new function appears in a magnetic crystal. Therefore, in ceramics manufactured using natural raw materials containing iron and exhibiting magnetism, the microcrystalline phase of the magnetic material is interspersed and formed, and the ceramic is caused by frustration in the micromagnetic crystal. It is thought that it is necessary to consider the possibility that these functions will be manifested.

  On the other hand, when the magnetic field of the magnet acts on normal water having the characteristics of a diamagnetic material, it has been announced that the size of the water cluster increases (Non-Patent Document 5). An apparatus for producing magnetized water (Patent Document 9) has been developed which becomes the formed magnetized water. This magnetized water is said to have a function of reducing the amount of scale in water pipes and an effect of reducing the generation of tartar when used for oral cleaning liquid in dentistry (Patent Document 9).

  In addition, a phenomenon similar to the phenomenon that occurs in magnetized water, in which water that has passed through special ceramics reduces the scale in metal piping, has also been recognized for water that has passed through special ceramics (Non-Patent Document 6). At present, it is difficult to rationally explain the causes of these phenomena, but it is thought that one of the reasons is that the nature of water is changed due to the magnetic substance contained in the ceramics. .

(Method for producing functional ceramic)
Next, a method for producing functional ceramics will be described. Many ceramic manufacturing methods called functional ceramics are manufactured using the latest synthetic techniques such as sputtering, CVD, and solution methods using pure chemicals as raw materials. Many of the functions appearing in these ceramics can clearly explain the cause of the function scientifically.

  However, some ceramics called functional ceramics use various natural raw materials containing multiple components, and some ceramics are produced by crushing, mixing, molding, and firing processes in the same way as general ceramics. In some cases, it is difficult to fully explain the cause of the function that appears in ceramics.

  For example, in order to produce functional ceramics, the oxidation-reduction state of the ceramics varies depending on the firing conditions. In the production of functional ceramics using a general furnace such as a gas furnace, skillful technology is required to produce ceramics by artificially adjusting the state of the flame in the furnace to an oxidizing flame or a reducing flame. Met.

  The carbon contained in the ceramics burns in the porous ceramics fired at high temperature to form a dilute, oxygen-reducing state, so the metals compounded inside the ceramics are reduced state electrons. It is estimated that it is easy to arrange.

As understood from the fact that carbon is used for the reaction of reducing silicic acid to metallic silicon at high temperature, it has strong reducibility at high temperature. Due to this reducibility, for example, trivalent iron atoms are considered to obtain electrons and be reduced to divalent iron atoms.
This reaction is represented by a chemical reaction formula.
6Fe ₂ O ₃ (trivalent iron) + C → CO ₂ + 4 Fe ₃ O ₄
2Fe ₃ O ₄ + C → CO ₂ + 6 FeO (divalent iron)
The iron oxide changes in crystalline phase with γ-Fe ₂ O ₃ (maghemite), Fe ₃ O ₄ (magnetite), and FeO (wustite). An oxide with a non-stoichiometric composition can also be produced (Non-Patent Document 7).

  Since transition metal crystals and clusters and intermetallic compounds often produce oxides of non-stoichiometric composition, transition metals such as titanium, manganese, zirconium, tungsten, added to the porous ceramic of the present invention, Yttrium, rare earth elements, and the like can also be reduced with carbon to become non-stoichiometric oxides.

  Patent Document 1 shows that “a calcined molded article having a redox ability produced from limonite, clay and charcoal” exhibits various environmental purification actions by the redox action of iron contained in the limonite soil of Aso (Patent Documents). Focusing on 6-8), a method for firing and molding a limonite kneaded product in a wood kiln is disclosed. This Patent Document 1 describes the use of water vapor, but it is said to be “a structure that naturally generates water vapor from the ground of a wood kiln” and “is generated naturally from the ground at the bottom of the kiln. It is said that the pressure in the furnace is higher than usual due to the action of water vapor and contributes to the firing of the molded product.

  Each of the functional ceramics of Patent Documents 1 to 5 uses zeolite or tourmaline ore as a main raw material, and adds a raw material composed of several kinds of mixtures or compounds, etc., and a ceramic furnace firing furnace or an inert gas atmosphere furnace. Manufactured using.

(Superheated steam)
Next, superheated steam that may be used in the production of functional ceramics will be described. The superheated steam is generally generated by heating normal temperature saturated steam by electromagnetic induction heating or bringing it into contact with a high-temperature heat medium to raise the temperature to 100 ° C. or higher. Although superheated steam is currently equipped in a microwave oven, it is generally used for drying processing of foods at a temperature of about 100 ° C to 300 ° C.

  Regarding utilization of high-temperature superheated steam at 300 ° C. or higher, carbonization of organic matter (Patent Document 10, waste treatment (Patent Document 11), production of activated carbon (Patent Documents 12 to 15), activated carbon regeneration device (Patent Document 16, 17) In addition, although not referred to as superheated steam, steam reforming technology (Patent Document 18), which is a technology for converting hydrocarbon fuel gas into hydrogen, also has a high temperature of 700 ° C. or higher. Steam (equivalent to superheated steam) is used.

In the reforming technology of hydrocarbon fuel, high-temperature steam reacts with hydrocarbon fuel such as natural gas in the presence of a metal catalyst by the reaction mechanism shown below.
C _n H _m (hydrocarbon fuel) + n H ₂ O → n CO + (m / 2 + n) H ₂
CO + H ₂ O → CO ₂ + H ₂
(N and m indicate the number of moles of each element and compound)

On the other hand, although charcoal is not a hydrocarbon, if an appropriate metal catalyst is present, it is considered that carbon constituting the charcoal reacts with high-temperature superheated steam by the reaction mechanism shown below.
C _n (charcoal) + n H ₂ O → n CO + n H ₂
nCO + nH ₂ O → nCO ₂ + nH ₂
Although not shown in this chemical reaction formula, water (H ₂ O) itself is dissociated into hydrogen and oxygen on a high-temperature catalyst, and the generated oxygen burns and consumes carbon to generate CO ₂ . It is estimated to be.

  Using these reactions, there is a technique for converting charcoal into activated carbon having a large specific surface area by bringing the charcoal into contact with high-temperature steam, which is called charcoal steam activation. Steam activation of charcoal is a technique in which the carbon constituting the charcoal is gradually consumed (burned) by the above reaction mechanism to form fine pores and gradually increase the specific surface area. Since charcoal originally contains potassium, iron, etc., it is considered that these metals contribute to the development of fine pores by exhibiting catalytic action.

Activated carbon is excellent in the adsorption performance of various substances and is used in various fields. The easy and inexpensive production of high-performance, that is, high specific surface area activated carbon is an urgent issue particularly for the removal of radioactive waste in the nuclear accident. Furthermore, it is a future problem to establish a mass production method of super activated carbon having a specific surface area of 3000 m ² / g or more.

  As a conventional technique using superheated steam, a method of using atmospheric superheated steam for firing ceramics is disclosed in Patent Document 19 as “a method for producing ceramics and a ceramic firing furnace”. The superheated steam shown in this patent document is superheated steam of 300 ° C. or lower, which is generally used for drying processing of foods, and the purpose of drying the ceramic molded body before firing, and the ceramic after firing. Used for cooling purposes.

  On the other hand, there is a method called hydrothermal synthesis as a method for producing ceramics using water vapor, synthesis of a zeolite membrane by hydrothermal synthesis (Non-Patent Document 8), and hydrothermal synthesis shown in a heating member (Patent Document 20). An example is ceramics. The former hydrothermal synthesis of the zeolite membrane is hydrothermal synthesis for several hours at 100 ° C., and the latter exothermic member is said to be synthesized by steam curing in an autoclave after pressure molding. As described above, although hydrothermal synthesis uses steam, the synthesis reaction of ceramics is performed in steam of an autoclave.

(Porous structure)
Next, the porous structure of the porous ceramic will be described. Porous ceramics are utilized as adsorptive separations and filters of gases, liquids, ions, etc., and catalyst carriers by taking advantage of their high specific surface area or their sharp pore size distribution.

  IUPAC (International Genuine Applied Chemistry Union) is a macroporous body with pores larger than 50 nanometers and mesoporous with pores in the range of 2-50 nanometers, depending on the pore size of the porous material. The body is classified as a microporous body having pores of 2 nanometers or less. The pores of 50 nanometers or more are called macropores, the pores in the range of 2 to 50 nanometers are called mesopores, and the pores of 2 nanometers or less are called micropores.

  The pores in the micropore region of the porous ceramics are in a wide range of 0.05 μm to several hundreds μm. When the pore distribution of the preceding microporous porous ceramics is investigated, for example, in the patent document, 1 μm A ceramic porous body having the above macropores (Patent Document 21), which is a ceramic porous body and has an average pore diameter of 20 micrometers or less (Patent Document 22), etc. The upper limit value or lower limit value of the pore diameter of the pore is shown, and the actual state of the pore diameter distribution in these ranges (peak value of the pore diameter distribution) is unknown.

  Moreover, the network ceramic product of (Patent Document 23) is a porous body having a combination of macropores, mesopores, and micropores, and has a volume ratio of three kinds of pore structures of macropore volume, mesopore volume, and micropore volume. Although the pore structure of reticulated ceramics is characterized, the pore size distribution of macropores is not expressed.

  On the other hand, Patent Document 24 discloses a method for producing a ceramic porous body having a composite pore structure having a composite pore structure of macropores and micropores. This manufacturing method is a method in which the water-containing slurry of the ceramic raw material is frozen, the ice is sublimated, and then fired.

  Porous functional ceramics have air permeability, but such porous ceramics having air permeability are expressed as a continuous porous body, and a method for producing a highly continuous porous body is disclosed (patent) Reference 25). This method is manufactured by immersing a composite of a water-insoluble material and a water-soluble polymer fiber in water, dissolving and removing the water-soluble polymer from the composite, and then firing.

  These ceramics having the communication characteristics have significant characteristics when the ceramics are fired. That is, in general firing of ceramics, if bubbles, charcoal, and other vaporized foaming components are present in the ceramic raw material molding, there will be a problem of bursting or cracking during firing at a high temperature. In the case of high quality ceramics, the gas component that expands can escape to the outside, so that bursting and cracking are greatly reduced, facilitating the production of molded products.

(Far infrared radiation performance)
Next, the far infrared radiation performance of ceramics will be described. In the far-infrared rays of practical use issued by humans and historians, far-infrared rays are said to be the basic technology of advanced businesses such as new energy development, biotechnology, and new material development. Non-patent document 9) summarizes a large amount of patent information related to far infrared rays up to 1997. Among them, the use of far-infrared rays covers a wide range of fields such as the medical health field, the food field, the mechanical / thermal energy field, the chemical field, the information measurement field, and the daily necessities field.

  As for the past far-infrared radiation materials, there are many examples of “emitters” classified in the chemical field in the above non-patent literature. Although several tens of cases are listed as ceramic far-infrared radiators, the porous far-infrared radiators disclosed in Patent Document 26 and the porous far-infrared radiator disclosed in Patent Document 26 Two cases of heat-resistant ceramic heating medium.

  In these two patent documents, the ceramic powder or the far infrared radiation ceramic powder is manufactured by firing, and the former average pore diameter is 10 to 200 μm. It is difficult to produce ceramics having a continuous pore structure with ceramics obtained by firing powder, and from the composite pores of macropores, mesopores and micropores with uniform pores similar to the porous functional ceramics of the present invention. It is also difficult to form a pore structure.

  Examining patent documents from 1997 onward, a method for producing a linear infrared emitter capable of generating negative ions in addition to far infrared radiation is disclosed. Such patent documents include “a method for producing far-infrared radiation ceramics” (patent document 28), “a method for producing functional ceramics” (patent document 29), “far-infrared radiation characteristics, antibacterial properties, deodorizing properties, and hormesis. “Composite ceramics having effect and high wave number and generating negative ions and manufacturing method thereof” (Patent Document 30). In the far infrared radiator manufacturing method of Patent Document 28, argon gas or nitrogen gas is blown, and the firing atmosphere is a non-oxidizing atmosphere.

  The far-infrared radiator of this patent document is a far-infrared radiator having a porous structure because it is manufactured by adding organic binder resin or charcoal to main raw materials such as fly ash, volcanic ash, and clay. Although it is presumed, the pore structure is not described, and the presence or absence of air permeability is unknown.

  In addition, Patent Document 31 and Patent Document 32 also describe far-infrared radiation and radioactivity of negative ions, but the former is high-temperature firing in a gas displacement furnace, and its pore structure is unknown. The latter is a finely pulverized and mixed state of some natural rocks and is used without firing.

(Reduced water)
Functional ceramics are also used in the production of reduced water. Reduced water includes electrolytic reduced water produced by electrolytic reduction of water and reduced water produced by functional ceramics. In the medical field, electrolytic reduced water is a biologically functional water that eliminates active oxygen generated in the living body. Has begun to be confirmed (Non-Patent Document 10).

  The functional ceramics exhibit reduction performance against water as disclosed in Patent Documents 2 to 5. These functions are presumed to be manifested by the action of metal oxides contained in ceramics, non-stoichiometric metal oxides, noble metal fine particles, or magnetic compounds mainly composed of iron atoms. Is done. As described above, there are many cases where the cause of the function of ceramics produced by firing in a general firing furnace using natural raw materials composed of multiple components cannot be sufficiently explained scientifically.

(Prior art proposed by the applicant)
The applicant, from a raw material composition containing charcoal, ceramic raw materials, bone ash, etc., contains charcoal and carbon components in a composite, and has a breathable charcoal composite glass ceramic (Patent Document 33) and a metal developed thereafter. Disclosed is an electrically conductive carbon composite porous ceramic (Patent Document 34) to which an oxide is added in several percent by molar mass. These ceramics are manufactured using a normal electric furnace or gas furnace, and the molded product before firing is stored in a sheath container together with charcoal powder and covered at a temperature of 1150 to 1300 ° C. As a result of firing the raw material molded product together with the charcoal powder in a sheath container, charcoal or a charcoal composite ceramic containing carbon content was produced in the ceramic.

  In addition, porous ceramics having fine pores formed by the action of bone phosphate-derived calcium phosphate added to the ceramic raw material and having air permeability through the through-holes are manufactured, and charcoal or calcined added to the raw material As a result, a charcoal composite porous material having electric conductivity due to the continuous phase of the generated carbide was produced. In order to test the effective use of these charcoal composite porous materials, charcoal composite glass ceramics (Patent Document 33) was used in a water purification test, and as a result, good water quality was maintained and purified. It was.

JP 2004-10473 A JP 2000-63173 A JP 2000-79339 A JP-A-11-43365 JP 2008-126224 A JP 2005-262209 A JP 2010-131556 A JP 2011-183294 A Special table 2003-534127 gazette JP 2007-138122 A JP 2007-181784 A International Publication No. 2005/063923 Special Table 2002-543268 JP 2009-179485 A JP 2009-292670 A JP 05-254379 A JP 2011-184272 A JP 2002-356308 A JP 2007-230796 A JP 2001-338748 A JP 2008-156170 A JP 2004-2130 A Japanese Unexamined Patent Publication No. 7-18784 JP 2001-192280 A JP 2009-24067 A JP-A-63-40773 Japanese Patent Laid-Open No. 3-97680 JP 2003-112962 A JP 2006-225247 A JP 2008-290891 A JP 2006-225247 A JP 2008-290891 A JP 2004-175576 A JP 2008-56505 A

Naonobu Katada, Jun-ichi Endo, et al., J. Phys. Chem. B, 2000, 104 (44) p10321-10328, “Superacidity and Catalytic Activity of Sulfated Zirconia” Susie Eustis and Mostafa A. EL-sayed, Chem.Soc.Rev., Issue 3, 2006, 35, 209-217, “Why gold nanoparticles are more precious than pretty gold: Noble metal surface plasmon resonance and its enhancement of the radioactive and nonradioactive properties of nanocrystals of different shaped. ” EW Elcock “Antiferromagnetism and ferrimagnetism of nonstoichiometric compound” Proceedings of the Royal Society of London.Series A, Mathematical and Physical Sciences, Vol. 227, No. 1168 (Dec. 21, 1954), pp. 102-114 Published by The Royal Society London Geometrical frustration- Wikipedia Geometrical frustration: //en.wikipedia.org/wiki/geometrical_frustration R. Cai, H. Yang, J. He, W. Zhu, The effects of magnetic fields on water molecular hydrogen bonds, J. Mol. Struct. 938 (2009) 15-19 Rika Suto, Momoko Kaga, Kimiko Tanabe, Katsumi Ishikawa, Hot Spring Science, 51, 2002, p165-174, Study on prevention of hot spring scale by ceramic fluid water treatment Sandra E. et al. By Dan, Katsuhisa Tanaka, Basics of Solid State Chemistry, p132, Doujin Kagaku, 2003, Tokyo Yuji Iwamoto, Hiroshi Kawamoto, “Research and Development Trend of Nanoporous Separation Membrane”, p6, Science and Technology Trend, February 2009, Ministry of Economy, Trade and Industry Koichi Takada, Yoshinobu Egawa, Hisao Sasaki, separate volume for practical far infrared rays, patent information on fields and far infrared rays, published by Human and History Company, 1999, Tokyo Nihon Trim, website, research and development, related paper http: //www.nihon-trim.co.jp/research/conference/2010.html Koichi Takada, Yoshinobu Egawa, Hisao Sasaki, Practical far-infrared infrared separate volume, field-specific far-infrared related patent information, p812, "Gasoline activator", Human and History Company Publishing, 1999, Tokyo

  However, when an electrically conductive carbon composite porous ceramic (Patent Document 34) is immersed in water, a reddish brown metal oxide is eluted in the immersed water after 12 hours or more, and it becomes an inappropriate material for water purification. The problem that occurred.

  Moreover, the charcoal composite porous ceramic (Patent Document 34) is obtained by adding a large amount of metal oxides to a ceramic raw material and firing it together with charcoal, thereby causing chemicals caused by the metals reduced by carbon. Although the reduction performance was expected to appear, no significant change in function could be recognized except that the electrical conductivity was slightly improved.

  SUMMARY OF THE INVENTION The present invention is intended to solve the above-described problems, and an object thereof is to provide a functional ceramic that is suitable as a water purification material and has reduction performance, and a method for producing the same.

  In order to solve the above-described problems, the functional ceramics according to the present invention is obtained by first firing a ceramic material containing charcoal and iron oxide and then secondarily firing with superheated steam. It is preferable that the ceramic material includes at least one of a rock ground material, a ceramic raw material including silicic acid and alumina, a silicon compound, and an aluminum compound. Preferably, the ceramic material includes limonite and the iron oxide is provided by limonite. The charcoal preferably includes at least one of charcoal, bamboo charcoal, coffee charcoal, coconut shell charcoal, coal coke, and petroleum coke. The ceramic material preferably contains at least one of zirconium, silver, palladium, gold, platinum, manganese, titanium, tungsten, yttrium, cerium, and neodymium.

The primary firing is preferably performed in a temperature range of 1150 ° C to 1300 ° C. The secondary firing is preferably performed in a temperature range of 300 ° C. to 700 ° C. or 700 ° C. to 900 ° C. for 1 to 24 hours. The fired product preferably has mesopores in the range of 2 to 50 nanometers and micropores of 2 nanometers or less.

The ceramic material, _SiO in mole percent _{2: 40~60%, Al 2 O} 3: 15~30%, CaO: 5~20%, MgO: 1~20%, Na 2 O: 1~10%, K ₂ O: 1 to 10%, Fe ₂ O ₃ : 2 to 10%, P ₂ O ₅ : 0.01 to 5.0%, TiO ₂ : 0 to 10%, MnO ₂ : 0 to 5.0% It is preferable to be in the composition range.

  The invention of the method for producing functional ceramics according to the present application includes a primary firing step of firing a ceramic material containing charcoal and iron oxide, and a secondary firing of further firing the ceramic material fired in the primary firing step with superheated steam. Is included. It is preferable to include a step of creating the ceramic material from at least one of a rock ground material, a ceramic raw material containing silicic acid and alumina, a silicon compound, and an aluminum compound.

  The primary firing step is preferably performed in a temperature range of 1150 ° C to 1300 ° C. The secondary firing step is preferably performed in a temperature range of 300 ° C. to 700 ° C. or 700 ° C. to 900 ° C. for 1 hour to 24 hours. In the primary firing step, it is preferable to cover the molded material of the ceramic material with charcoal particles and store in a fired sheath to fire.

  An invention of a superheated steam generator according to the present application provides superheated steam used in a method for producing functional ceramics, and includes a tube filled with ceramic particles therein, and a heating unit that heats the tube from the outside. And saturated steam is introduced into the tube and heated by the ceramic particles maintained at a predetermined temperature to generate superheated steam.

  The superheated steam firing furnace according to the present application is used in a method for producing a functional ceramic, and is provided in a cylindrical portion that houses a container of a sample to be fired, and a lower portion of the cylindrical portion, and heats the steam. A steam heating unit that supplies the cylindrical part; and a heating unit that heats the cylindrical part and the steam heating part from the outside. The steam heating part guides superheated steam supplied from the outside to the cylindrical part. A flow path is formed, ceramic particles are filled therein, and the superheated steam is heated and maintained by the ceramic particles maintained at a predetermined temperature to maintain the temperature of the superheated steam.

  Applicants have conducted extensive research, and after conducting secondary firing by contacting the electrically conductive charcoal composite porous ceramics once produced with superheated steam in the high temperature range for several hours, it becomes turbid even if left in water for a long time. Porous ceramics can be produced, and chemical analysis of the water in which the ceramics after superheated steam firing were immersed revealed that there was no iron or other metal ions that were abnormally dissolved from the ceramics. confirmed.

  When the pH of this ceramic immersion water was measured with a pH meter, a very high pH value was measured, so the ceramic was immersed in distilled water, and changes in pH of the immersion water and changes in oxidation-reduction potential over time were investigated. . As a result, when the ceramic secondarily fired with superheated steam is placed in distilled water having a redox potential of about +500 mV, the redox potential of the distilled water is lowered to a potential of about +200 mV, and at the same time, the pH is reduced to about pH 6.5. It was confirmed that the value was increased to a value of about pH 10.5.

  Such a decrease in oxidation-reduction potential and an increase in pH are also recognized for electrolytic reduced water produced by electrolysis of water, and the porous ceramic of the present invention is a reducing performance that converts ordinary tap water into reduced water. It was thought to have

  The functional ceramic of the present invention is produced by producing a porous ceramic containing carbon in primary firing and subsequently firing with high-temperature superheated steam. Regarding the above-mentioned problems that have occurred with respect to the electrically conductive carbon composite porous ceramics produced by the production method of Patent Document 34, secondary firing with high-temperature steam at 700 ° C. or higher at normal pressure, that is, high-temperature superheated steam is performed. I tried to solve it.

  However, in ceramics containing a charcoal or carbonized component in combination with a metal oxide such as an electrically conductive charcoal composite porous ceramic (Patent Document 34), the carbon component contained in the ceramic is a high-temperature superheated steam. It was considered that there was a possibility that it was removed by reaction and firing with superheated steam could be effectively achieved. That is, in the electrically conductive charcoal composite porous ceramic produced in the above-mentioned Patent Document 34, charcoal powder of 10% or more by weight is added to the raw material, and in the primary firing, together with the charcoal in the fired sheath. As a result of firing, the porous skeleton contains fine particles of charcoal and carbon compounds derived from charcoal (SiC or metal carbide).

  General ceramics showed electrical insulation, but the charcoal composite porous ceramic after primary firing had electrical conductivity of about several hundred Ω. Therefore, it was presumed that carbon and carbide portions having electrical conductivity exist continuously throughout the porous structure. Carbon composite porous ceramics have a continuous carbon content and have gas-permeable through pores. Therefore, superheated steam can react with the carbon content at various locations inside the ceramic. Was considered to be removed by reacting with hot superheated steam.

  As the carbon content of the carbon particles and metal carbides in the porous ceramics is removed, the basic skeletal structure of ceramics such as -O-Si-O- and -O-Al-O- It was considered that the ceramics were fired by superheated steam as the skeletal structure became more dense. In the present invention, the charcoal composite porous ceramics produced by the primary firing in accordance with the same production process as in Patent Document 34 was subjected to secondary firing with high-temperature superheated steam.

  On the other hand, when the far-infrared radiation performance of the porous ceramics after the secondary firing with superheated steam was investigated, the measurement result that it had high far-infrared radiation performance was obtained. Therefore, it was confirmed that the porous ceramic of the present invention is a functional porous ceramic having a porous structure, reducing performance, and high far-infrared emission performance.

  There are many materials with far-infrared radiation performance and their uses are various (Non-Patent Document 9), but the far-infrared radiation ceramic of the present invention is porous having macropores and mesopores, as will be described later. It is a far-infrared radiator having a quality structure and reducing performance. If the porous material has reducing performance and far-infrared radiation performance, a large interface can be formed between the contacting gas substance or liquid substance, and interaction such as electrons and energy transfer can be performed effectively. It is considered to be.

In the present invention, iron oxide or a soil containing a high concentration of iron oxide is used as a part of the ceramic raw material, and the raw material contains about 2 to 6% of iron (Fe ₂ O ₃ ) in mole percent. doing. When iron oxide is present in the ceramic, an oxidation-reduction reaction occurs by transferring electrons between a divalent iron atom and a trivalent iron atom, which contributes to the oxidation-reduction catalytic activity.

  In the functional porous ceramic of the present invention, magnetization was observed in many fired bodies after the primary firing, but depending on the temperature difference of superheated steam during the secondary firing, the porous porous ceramics remained magnetized. Ceramics and porous ceramics with changed magnetism and no longer recognized magnetism were also produced. However, at present, the cause of the change in magnetism of the porous functional ceramic of the present invention and the relationship between the change in magnetism and the function of the ceramic are unknown.

The ceramic after the high-temperature superheated steam firing of the present invention was produced in a grayish black state that is considered to contain FeO or Fe ₃ O ₄ . When the ceramics produced in gray-black color were baked in an oxidizing atmosphere furnace at 400 to 600 ° C., the color changed to reddish brown, which is a characteristic color of Fe ₂ O _3. It was judged that it was.

  The functional porous ceramic of the present invention has a pore structure similar to that of the charcoal composite glass ceramics (Patent Document 33), the electrically conductive charcoal composite porous ceramics (Patent Document 34), etc., on which the development was based. However, these charcoal composite materials are different in that the pore distribution in the mesopore region and the nanopore region is greatly developed by firing the superheated steam at a higher temperature.

  In the present invention, superheated steam in a high temperature range of 700 ° C. or higher is used for the secondary firing of the ceramic, and the functional ceramic is manufactured by a completely different method from the prior invention. When the functional ceramic of the present invention is compared with the functional ceramics of the prior disclosure, in addition to the clearly different manufacturing method, the functional ceramic of the present invention has more pores in the micrometer region and the nanometer region. It is very different in that it is a functional ceramic with a developed porous structure.

  The functional porous ceramic of the present invention has a composite pore structure having a macropore having a pore diameter of about 1 μm, a mesopore and a micropore having a diameter of 10 nanometers or less, and is also a breathable continuous pore structure. The present invention defines the presence of macropores of uniform pore size measured in a specific range with a sharp shape. The cause of macropore formation is thought to be due to the action of bone ash containing calcium phosphate, but it is not clear.

  In view of the above-mentioned advanced research and such actual phenomenon, it was considered necessary to consider the functional change given to the porous ceramics by the magnetic material contained in the ceramics. As a metal that has the possibility of forming a magnetic compound such as a spinel structure by combining with iron atoms, manganese, titanium, tungsten, yttrium, cerium, neodymium, etc. are combined and used in the raw material composition as necessary. Yes.

  In addition, zeolite, tourmaline, shell, coral, barleystone, limonite, and the like are specified and used as the raw material components that give functions to the above-described functional ceramic raw materials previously disclosed, but in the present invention, the chemical composition With respect to various natural materials having different values, porous functional ceramics can be produced by supplementing necessary chemical components and adjusting the total chemical composition. Another problem is to ash shellfish such as oyster shells, scallop shells, and pearl oyster shells that are discharged as industrial waste in fishery and effectively use them as agricultural soil neutralizers.

  In addition to the characteristics of the porous ceramics, the porous functional ceramics of the present invention are obtained by reducing metal oxides contained in the porous skeleton by reacting with carbon in high-temperature superheated steam. The skeleton itself has the ability to exhibit redox performance.

  Regarding the preferred raw material composition or chemical composition of the functional porous ceramics produced in the present invention, porous ceramics of various compositions are produced, and the pH and redox potential are measured each time to obtain a high pH and low redox. The composition showing the potential was selected by trial and error.

  As described above, the porous functional ceramic of the present invention is different from a porous material used as a simple adsorbent or a separation filter, and as a catalyst utilizing reducing properties, far-infrared radiation performance, negative ion generation performance, and the like. Or functional porous ceramics with far-infrared radiation and negative ion generation that can be used in the fields of medical health, food, machinery / thermal energy, chemistry, daily necessities, etc. and have strong reducing properties It has the potential for further development as a material.

  That is, the pore structure of the functional porous ceramic of the present invention is a continuous pore exhibiting gas permeability, and in addition to a relatively uniform macropore having a diameter of about 1 micrometer, it is several nanometers or less. Mesopores and micropores have been developed. Therefore, it is thought that it can interact with a large interfacial energy for a substance in contact with ceramics. For example, the oxidation / reduction ability can be used to reduce gaseous or liquid substances simply by passing ceramics. When air is passed through ceramics, electrons move from the ceramic skeleton to oxygen in the air, resulting in negative ions. It is assumed that a function is generated.

  Further, the reduction performance by the ceramic skeleton and the far-infrared radiation performance are combined, for example, the combustion improvement effect of hydrocarbon fuel appears higher than that of the past far-infrared radiation material (Non-patent Document 11), and there is a possibility of improving fuel consumption. Conceivable. As described above, the porous functional ceramic of the present invention uses the firing method set for producing the electrically conductive charcoal composite porous ceramic (Patent Document 34) as the primary firing, and after this primary firing, 700 It is manufactured by applying unprecedented technology of high-temperature superheated steam baking, in which secondary baking is performed by bringing it into contact with superheated steam at about 900 to 900 ° C. for several hours or more.

  Therefore, in the ceramic manufacturing process, it is also a problem to provide a product that does not vary in its function through routine work without depending on the sixth sense of the skilled person. Although the present invention performs primary firing in charcoal particles and secondary firing with superheated steam, it can be produced without requiring skill.

It is a figure which shows the structure of a superheated steam baking furnace. It is a photograph which shows the distilled water which immersed the porous ceramic. It is a figure which shows the pore distribution of porous ceramics. It is a figure which shows the pore distribution of porous ceramics. It is a figure which shows the pore distribution of the porous ceramics by the amount of differential penetration. It is a figure which shows the pore distribution of porous ceramics. It is a figure which shows the pore distribution of porous ceramics. It is a figure which shows the light absorbency of the liquid mixture of ceramic reduced water and a superoxide detection reagent. It is a figure which shows the far-infrared radiation property of porous ceramics. It is process drawing which shows the manufacturing method of porous ceramics.

  FIG. 1 shows a high-temperature superheated steam firing furnace used for firing functional ceramics with superheated steam. The high-temperature superheated steam firing furnace is composed of a superheated steam generation unit and a superheated steam firing furnace 20. The superheated steam generator has first and second heating furnaces 17 and 19, and is configured to contact saturated steam with a far-infrared radiation material that has been heated to a high temperature. A pipe is placed, and the inside of the pipe of the heat-resistant steel 15 is filled with a far infrared radiation material.

  The saturated steam at 100 ° C. generated in the boiler 11 is introduced into the superheated steam generation section through the pipe 13 and is distant in the pipe by the heat-resistant steel 15 heated to a high temperature by the first heating furnace 17 and the second heating furnace 19. The temperature is raised to high-temperature superheated steam by contacting with the infrared radiation material while staying moderately. The flow rate of the saturated water vapor introduced into the superheated steam generation unit is set to 30 g / min to 200 g / min, preferably 75 g / min to 125 g / min.

When indicating this flow at a flow rate per unit cross-sectional area, the pipe portion of the superheated steam generating furnaces is approximately the flow rate of 1.5 g / min ^/ cm 2 ^{~10.2g /} min / cm ^2, the superheated steam fired furnace 20 approximately the flow rate of 0.2 g / min ^/ cm 2 to 1.2 g / min / cm ² at the sample container section, each preferably, 3.8 g in the pipe portion of the superheated steam generating furnaces / min ^/ cm 2 to 6. 4g / min / cm ^2, it is in the sample container portion of the superheated steam fired furnace 20 and 0.4 g / min ^/ cm 2 ^{~0.75g /} min / cm ^2.

  The far-infrared radiation material used as the heat medium is preferably the far-infrared radiation material produced in the superheated steam firing furnace of the present invention, and the steam is activated specially based on the characteristics of the functional ceramics with reducing performance. There is a possibility of becoming. However, the heat medium is not limited to the porous functional ceramic of the present invention. In FIG. 1, the first and second heating furnaces 17 and 19 are composed of two annular electric furnaces having an inner diameter of about 60 to 80 mm and a heating part length of 40 to 60 mm in accordance with the diameter of the heat-resistant metal pipe. Yes.

  The furnace temperature of the first heating furnace 17 into which the saturated steam is introduced is cooled by the introduced steam of 100 ° C. and hardly rises, so it is set somewhat higher than the target temperature of the superheated steam, The furnace temperature of the second heating furnace 19 is set to the superheated steam temperature for firing. The heating furnace can be a single heating furnace as long as the length of the heating element of the heating furnace is sufficient to raise the temperature of the superheated steam, and can be configured as a combustion furnace such as a gas furnace.

  The pipe 13 through which the superheated steam moves has an inner diameter of 50 mm and is configured by using a pipe made of heat-resistant steel 15 that can withstand a temperature of about 1000 ° C. It is filled with ceramics. The inner diameter of the pipe is not limited to 50 mm. The particle diameter of the far-infrared radioactive ceramics is about 5 to 10 mm, and is packed tightly so as not to move in the pipe. At this time, the far infrared radiation ceramics can be mixed and filled with a heat-resistant stainless steel ring.

  If the packing is loosely filled, the temperature of the superheated steam will not rise easily, and if fine particles are packed too densely in the pipe, pressure will be generated in the direction of the saturated steam and the steam will not flow. It is necessary. In the high-temperature superheated steam generator having such a structure, when saturated steam generated at 100 ° C. generated in the boiler is introduced into a heat-resistant steel pipe filled with far-infrared radioactive ceramics, In the pipe inside, the temperature is raised to high-temperature superheated steam in contact with a heat medium made of far-infrared radioactive ceramics heated to high temperature.

  Although it depends on the performance of the annular electric furnace, a pipe filled with far-infrared radiation performance with an inner diameter of 50 mm and a length of 1.2 meters is heated in the above two electric furnaces, and the temperature at the outlet of the pipe is 800 ° C. to It was possible to raise to 900 ° C.

  Next, the superheated steam baking furnace 20 on the left side of FIG. 1 will be described. The superheated steam firing furnace manufactured in the present invention is configured by a cylinder, and an outer cylinder 23 for introducing superheated steam is a cylinder having an inner diameter of 150 mm and a length of 800 mm, and a sample container 21 is inserted into the cylinder. The outer cylinder 23 is covered with a lid. The sample container 21 has an inner diameter of 145 mm and is manufactured to have a length of 100 mm, 150 mm, 250 mm, 450 mm, etc., and the lower part is manufactured to have a punched hole perforation structure so that steam can pass through.

  The superheated steam heated in the superheated steam generation furnace is introduced into the superheated steam firing furnace 20 described above, but when introduced into a larger volume space, the gas undergoes a rapid temperature drop as a natural characteristic. Therefore, when the superheated steam heated in the superheated steam generating furnace enters the outer cylinder of the superheated steam baking furnace 20 having an inner diameter of 150 mm from a pipe having an inner diameter of 50 mm, the temperature is greatly lowered.

  Therefore, as a measure for preventing a temperature drop, a steam heating unit is installed at the lower part of the outer cylinder 23 of the superheated steam baking furnace 20, and the steam heating unit is filled with particles of far-infrared radioactive ceramics as a heat medium. Is decreasing. Then, an annular furnace 25, 27, 29 having an inner diameter of 200 mm and a height of 250 mm is attached to the outer side of the outer cylinder of the steam heating unit, and the temperature is controlled by heating from the outside, and the high-temperature overheating necessary for firing the porous functional ceramics Designed to achieve and maintain water vapor temperature.

  The far-infrared radioactive ceramic particles used as the heat medium are stored in a sample container having an inner diameter of 145 mm and a length of 150 mm, and are inserted and set in the lower stage of the outer cylinder 23 so that the packing can be replaced as required. To. The heat medium is preferably a far infrared radiation ceramic, but is not limited thereto.

  A sample container 21 having a length of 250 mm to 450 mm is placed in the middle stage immediately above the steam heating unit, and the ceramic after the primary firing is filled in the container. For example, when producing activated carbon or shell ash, raw charcoal or shells are set in a sample container at this portion. Furthermore, a sample container with a length of 150 mm filled with charcoal particles having a particle diameter of 1.0 mm to 2.0 mm is placed on the upper stage of the sample, and a lid provided with a steam discharge port and a thermocouple insertion port at the upper part of the outer cylinder. Attach. Although the sample container filled with charcoal placed in the upper stage has an effect of appropriately retaining superheated steam in the outer cylinder 23, it is not always necessary to place it. An annular furnace having an inner diameter of 200 mm and a height of 250 mm is attached to the middle and upper stages of the outer cylinder 23, respectively, and is controlled so that the internal temperature can be maintained by heating from outside.

  The temperature in the furnace, that is, the temperature of the superheated steam passing through the ceramic sample is constantly measured by a thermocouple inserted through a hole formed in the lid on the top of the outer cylinder 23. That is, the temperature measured here becomes the temperature of superheated steam which processed ceramics. A preferable temperature for firing the porous ceramics with superheated steam was 700 ° C. to 900 ° C., and the firing was carried out at that temperature for about 1 to 24 hours.

  The function of the porous ceramics manufactured using such a superheated steam baking apparatus was particularly confirmed by the change in the properties of water in which the ceramics were immersed. Fig. 2 shows changes in the color of water after 12 hours have passed after the porous ceramics before the primary firing and the superheated steam firing and the porous ceramics after the superheated steam treatment are immersed in distilled water, respectively. Indicated.

  When porous ceramics that had been subjected to primary firing and had not yet been subjected to superheated steam treatment were immersed in distilled water, a brown precipitate of iron hydroxide as shown in FIG. However, the porous ceramic after the secondary firing with superheated steam did not become turbid even after a long time (several months or more) after being immersed in water as shown in FIG. . Table 1 shows the results of chemical analysis of the water in which the ceramics after the superheated steam firing were immersed by ICP emission spectroscopic analysis.

  It was confirmed that trace amounts of components contained in alkaline ionized water such as Mg: magnesium, Na: sodium, K: potassium, and Al: aluminum were eluted in the ceramic immersion water after the superheated steam firing. It was confirmed that transition metals such as Mn: manganese were not eluted.

  On the other hand, before and after the secondary firing with superheated steam, the pore structure of the porous ceramics was measured by mercury porosimetry. After the secondary firing, a peak of ultrafine pores appeared remarkably in the 10 nanometer region, and the pores were densified to nano size, and the effect of superheated steam firing was clear.

  FIG. 3 shows the pore distribution of the porous ceramics before and after baking with superheated steam as measured by a mercury porosimetry porosimeter. The broken line a in the figure has a pore volume of 47.35% before the superheated steam treatment, and the broken line b has a pore volume of 48.25% after the superheated steam treatment. As shown in FIG. 3, the secondary firing with high-temperature superheated steam has the effect of refining the pore structure of the charcoal composite porous ceramic, and the firing effect was confirmed even in the pore structure.

  Here, the characteristics of the pore structure of the porous ceramics produced by high-temperature superheated steam firing will be described by showing the pore distribution data measured with a porosimeter by the mercury intrusion method. FIG. 4 shows the pore distribution of a porous ceramic produced by performing primary firing at 1185 ° C. for 8 hours and then high-temperature superheated steam firing at 800 ° C. for 15 hours. In FIG. 4, the mercury intrusion amount is 0.32 ml / g and the porosity is 45.3%.

  In Fig. 4, the horizontal axis is the same as Fig. 3, the pore size of the porous ceramics is graduated, and the vertical axis indicates the amount of mercury intrusion into the pores of a specific size (Log Differencial Intrusion (ml / g)). It is graduated. This plotting method is a plot showing the amount of mercury that has entered the pores of each size, and the amount of mercury that has been injected is quantitatively shown to have entered most of the pores with a pore diameter of about 1 μm. Yes. Therefore, the pores shown in FIG. 4 are the most developed pores in the porous ceramic of the present invention, and the porous functional ceramic of the present invention compares the pores around 1 μm in diameter called macropores. It can be seen that they have uniform uniformity.

  Fig. 5 shows the pore distribution of the measurement data of the same sample as in Fig. 4 with the same plotting method as in Fig. 3 and the vertical axis representing the differential intrusion (ml / g / μm) of mercury. It was. The vertical axis of this pore distribution plot is the differential amount of mercury that penetrates into the pores, and it shows the quantitative change of mercury that penetrates into finer pores in stages as the pressure of mercury intrusion increases. It is a plot.

  In this plotting method, all the pores of 5 nanometers or more existing in the porous ceramics are measured and represented in the pore distribution. As shown in FIG. 5, it can be seen that the porous ceramic of the present invention has also developed pores in a pore region called mesopores of 10 nanometers or less. This nano-sized mesopore is presumed to be formed on the wall surface of the macropore. The measurement limit of the porosimeter used for this measurement is 5 nanometers, and pores of 5 nanometers or less cannot be measured, but micropores of 5 nanometers or less are also considered to exist.

  Next, the relationship between the primary firing temperature and the pore structure of the finally produced porous functional ceramic will be described. The primary firing temperature is preferably as high as possible because the porous ceramic skeleton structure is densely fired, but the maximum temperature that can be set in the primary firing depends on the overall chemical composition of the ceramic, and is at a temperature of 1200 ° C. or higher. Some compositions melt, deform and fuse when fired.

  Porous ceramics having a composition with an alumina content of 20 mole percent or more in the total oxide composition has improved heat resistance, and primary firing at 1250 to 1300 ° C. has become possible. However, when the composition having an alumina content of 20 mole percent or more is subjected to primary firing at a temperature of 1200 ° C. or lower, the sintered strength is weak and brittle porous ceramics are obtained.

  Table 2 shows a sample obtained by subjecting a raw material molding having an alumina content of 19 mole percent to primary firing at 1185 ° C. for 12 hours, and a raw material molding having an alumina content of 24 mole percent for 1185 ° C. for 6 hours. The pore characteristics of the porous ceramics produced by carrying out superheated steam firing at 700 ° C. for 24 hours for each of the samples fired by the firing method in which the temperature is raised to 1290 ° C. and stopped after the holding are shown.

  It can be seen that when the primary firing temperature is increased to 1290 ° C., the mercury penetration amount and the porosity corresponding to the pore volume are greatly reduced. From this, when producing a porous ceramics having a large pore volume with a porosity of 40% or more, a raw material composition having an alumina content of about 18 to 20 mole percent is selected and about 1185 ° C. It is preferable to perform primary firing at a temperature of 5 ° C. When producing a porous ceramic that has been hard-fired, a raw material composition having an alumina content of 20 to 25 mole percent is selected, and a temperature around 1280 ° C to 1290 ° C is selected. It is preferable to perform primary firing at a temperature. In addition, since the furnace which can set temperature of 1300 degreeC or more becomes very expensive, the raw material composition baked moderately at the temperature of 1300 degrees C or less is desired when the cost of a baking furnace is considered.

  Next, after performing primary firing by maintaining the temperature from 1185 ° C. for 6 hours to 1290 ° C. and holding for 1 hour, the pore distribution of the porous ceramics subjected to superheated steam firing at 700 ° C. for 24 hours This is shown in FIGS. 6 and 7 also show the pore distribution of the charcoal composite porous ceramic after the primary firing before the superheated steam firing. The broken line a in FIGS. 6 and 7 is before the superheated steam treatment, and the broken line b is after the superheated steam treatment.

  As shown in FIG. 6, the primary firing is performed at 1290 ° C. for 1 hour in addition to firing at 1185 ° C. for 6 hours, and even in porous ceramics manufactured in a more baked state, around 1 micrometer The pore diameters of the macropores were not significantly changed before and after baking with superheated steam.

  FIG. 7 shows that mesopores of 10 nanometers or less have developed after the superheated steam treatment, similarly to the data shown in FIGS. From these figures, it was clear that mesopores of porous functional ceramics were developed by superheated steam firing. Table 3 shows the mercury intrusion amount and the porosity before and after the superheated steam baking for the porous ceramics shown in FIGS.

  Comparing the pore characteristics shown in Table 3 with the pore characteristics of the porous ceramics primarily fired at 1185 ° C. shown in Table 2, the amount of mercury intrusion and voids in the primary firing at a higher temperature of 1290 ° C. The rate is greatly reduced, and it can be confirmed that firing is performed more precisely. Further, when the mercury penetration amount and the porosity are compared before and after the superheated steam baking, the mercury penetration amount and the porosity are increased after the superheated steam treatment. This result is considered to reflect that the carbon component reacts with the superheated steam and burns out, and the traces become vacancies.

  As described above, the redox function of the porous ceramic after secondary firing with superheated steam was confirmed by measuring the pH and redox potential of the immersion water in which the ceramic was immersed. In this confirmation test, distilled water was used, and 250 g of a ceramic formed into a spherical shape having a diameter of about 10 mm was placed in 0.7 liter of water, and the pH and oxidation-reduction potential after a certain period of time were measured.

  In this test, distilled water before immersing ceramics was measured with a pH meter using a glass electrode, the measured value was about pH 6.5, and the oxidation-reduction potential measured with a silver-silver chloride electrode was +250 mV to +300 mV. It was confirmed. This potential corresponds to a potential of +450 mV to +500 mV when converted to the potential of a standard hydrogen electrode.

  It was confirmed that the pH and oxidation-reduction potential of immersion water 12 hours after immersion of the ceramic reached pH of 10 to 10.5, and the oxidation-reduction potential also decreased to +20 mV to +100 mV (Ag-AgCl electrode potential). It was. Table 4 shows changes in pH and changes in redox potential over time of distilled water immersed in ceramics. The oxidation-reduction potential in the table is shown in terms of the potential with respect to the hydrogen standard electrode (NHE).

  Although some differences were observed in the measured pH and redox potential values due to differences in the raw material composition of the ceramics, all of the produced porous ceramic samples were alkaline with a pH of 9.0 or more. The pH value was maintained for about 30 days. A tendency for the pH to gradually decline over a long period of time was observed, but this was presumed to be due to the dissolution of carbon dioxide in the atmosphere.

Here, based on the ionic product of water, it is considered that the pH changes from around pH 6.5 of neutral water to pH 10.0 or more. According to the principle of water ion product, when the hydrogen ion concentration is [H ⁺ ] mol / L and the hydroxide ion concentration is [OH ⁻ ] mol / L, [H ⁺ ] × [OH ⁻ ] = 1 × 10 ^{− 14} mol ² / L ²

H ⁺ is actually OH ₃ ⁺ : hydronium ion. Therefore, [OH ₃ ⁺ ], which was present in neutral water by about 1 × 10 ⁻⁷ mol / L, decreased to 1 × 10 ⁻¹⁰ mol / L or less after 12 hours of immersion of the ceramic, [OH ^-] it is increased it up to 1 × ^10- 4 mol / L or more from 1 × ¹⁰ -7 mol / L to. The pH meter directly measures the hydrogen ion concentration based on the principle of a hydrogen ion concentration cell, and it is clear that the hydrogen ion concentration is reduced in the ceramic immersion water.

On the other hand, although the hydroxide ion concentration cannot be directly confirmed, pH test solutions such as commercially available BTB test paper, other pH test papers, or BTB solutions exhibit an alkali concentration, ie, [OH ⁻ ] mol / L. Give color. Therefore, the pH of the ceramic immersion water whose pH is 10.0 or more was measured with BTB, other types of pH test papers, and pH measurement solutions. The pH was measured with various pH test papers and pH measurement solutions. Almost all commercially available pH test papers had a display color of pH 7.0 or lower, and both the BTB solution and the commercially available pH measurement solution had a pH of 8. The color developed from 0 to pH 9.0 and did not change to an alkaline display color of pH 10 or higher.

According to the theory of ion product, the hydroxide ions must be increased from 1 × 10 ⁻⁷ mol / L to a concentration of 1 × 10 ⁻⁴ mol / L or more with the decrease of the hydrogen ions. However, the fact that the pH test paper and the pH test solution do not show a display color of pH 10.0 or higher measured with a pH meter means that the concentration of hydroxide ions: [OH ⁻ ] at a general pH of 10 × It is presumed that hydroxide ions have not increased to 10 ⁻⁴ mol / L. In this way, in the ceramic immersion water, it is considered that the hydroxide ion concentration has not changed to the theoretical concentration of the ionic product, so that the hydrogen ions are adsorbed and bonded to the reducing ceramics or to hydrogen atoms. It is considered that the concentration was reduced due to reduction.

Generally, water called reduced water is produced by electrolysis of water and is called electrolytic reduced water. Some field-reduced water has a pH meter value exceeding pH 11.0, and the oxidation-reduction potential is -200 mV to 100 mV (Non-patent Document 10). However, no description referring to [OH ⁻ ] (hydroxide ion concentration) of reduced water with electrolytic reduced water was found.

  From such changes in pH and oxidation-reduction potential, the functional porous ceramic of the present invention was considered to have the ability to generate ceramic reduced water similar to electrolytic reduced water. In this way, the reduction performance of ceramics that could not be confirmed in the charcoal composite porous ceramics of Patent Document 2 was confirmed, and the problem of imparting chemical functionality to the ceramics was solved.

From these changes in pH and oxidation-reduction potential, the functional porous ceramic of the present invention was considered to have the ability to generate ceramic reduced water similar to electrolytic reduced water. A superoxide erasing test was conducted. The superoxide anion radical (abbreviated as superoxide) indicated by the chemical symbol of O ₂ ⁻ has a function of protecting against pathogenic bacteria in vivo, but also has a function of generating harmful peroxide in vivo. doing.

  Field-reduced water has the effect of reducing and eliminating this superoxide, and has been shown to be effective in several pathological conditions (Non-patent Document 10). Since ceramic reduced water produced using the functional porous ceramic of the present invention is expected to have the same function as electrolytic reduced water, the superoxide elimination test was conducted to confirm the ability as reduced water.

  The superoxide elimination test uses superoxide generated by irradiating 470-nm light to an aqueous riboflavin solution, and the superoxide measurement is a change in absorbance due to reaction with a nitro-blue-tetrazolium (NBT) reagent. It was done using. Although the NBT solution has a yellow color, when it reacts with superoxide, a blue colored diformazan (Diformazan; light absorption wavelength: 560 nm) is generated. Therefore, superoxide can be measured with a change in absorbance at 560 nm.

  In this measurement, when a certain amount of NBT is added to a riboflavin solution and irradiated with light of 470 nm, superoxide from riboflavin is generated, and the generated superoxide reacts with the added NBT to form diforman. Generate. Thus, the yellow NBT-added riboflavin solution turns blue. Therefore, the amount of superoxide produced can be measured by measuring the absorbance at the blue light absorption wavelength (560 nm) proportional to the amount of diformazan produced.

  In an actual superoxide elimination test, when a substance that eliminates superoxide (called a scavenger) is added to a riboflavin solution to which NBT has been added, the amount of diformerzan produced decreases by the amount of superoxide elimination. The reaction principle that the absorbance at 560 nm decreases was used.

  FIG. 8 shows the results of testing whether the ceramic reduced water has a function as a scavenger. FIG. 8 shows the absorbance at 560 nm absorbed by diformazan on the vertical axis, and the riboflavin concentration proportional to the amount of superoxide produced on the horizontal axis. The broken line a in the figure indicates 2.45 mM, NBT-added ceramic reduced water, and the broken line b indicates 2.45 mM, NBT.

  In the superoxide elimination test, the change in absorbance when a certain amount of NBT and ceramic reduced water was added to the riboflavin solution was compared with the change in absorbance when the same amount of distilled water was added instead of ceramic reduced water. Indicated. When ceramic reduced water was added, the amount of die formazan produced was clearly reduced, and it was clear that the ceramic reduced water functions as a scavenger for eliminating superoxide.

Next, the far infrared radiation performance of the porous functional ceramic will be described. FIG. 9 shows the far-infrared emissivity measurement results of the functional porous ceramics measured with the Shimadzu Fourier transform infrared spectrophotometer IR Prestige-21 emissivity measuring apparatus. Curves a, b, c, d, and e in the figure are investigations of the effects of addition of transition metals, where a is ferric oxide, b is copper oxide, c is zinc oxide, d is germanium oxide, e is manufactured by adding 2.5 mol% of titanium oxide.
Most of the measurement wavelength region is a so-called infrared wavelength region, but far-infrared radiation performance is generally measured in this wavelength range.

  The porous ceramics of the present invention showed a high far-infrared emissivity of 80% to 90% of the far-infrared radiation blackbody used for the measurement control, although some differences were recognized depending on the difference of the added metals. The above-mentioned porous structure having nano-sized fine pores has a reduction performance, that is, an electron donating property, and in addition, the application development of the functional porous ceramics of the present invention exhibiting excellent far-infrared radiation performance is greatly developed. Be expected.

Next, utilization of the superheated steam baking apparatus for other applications will be described. Using the superheated steam calciner of the far-infrared ceramic specification of the present invention, when low-grade coconut shell charcoal of about 1 kg is treated with high-temperature superheated steam at 850 ° C. for several hours, the charcoal having a specific surface area of 1 m ² / g or less from the specific surface area of 500m ² / g~1500m ² / g activated carbon is readily produced. The rapid increase in specific surface area of activated carbon may have occurred due to both the substructure for maintaining the temperature of the superheated steam firing furnace used in the present invention and the effect of superheated steam passing through the far-infrared radiation ceramics. Can be considered.

Moreover, when the oyster shell was baked with superheated steam at 500 ° C. to 800 ° C. for several hours, organic substances in the shell were removed, and a nearly white particulate porous ash was produced. The composition of the shell ash is as follows: CaO: 93.5, SiO ₂ : 1.5%, Na ₂ O: 2.0%, K ₂ O: 1.0%, MgO: 1.0%. there were.

In ashing with superheated steam, it is cooled to about 100 ° C with water vapor after ashing, so it contains slaked lime (calcium hydroxide) instead of quick lime, and generates a large amount of gas when reacted with acetic acid. Was estimated as the main component. Therefore, this shell ash can be used as it is after neutralization of acid soil after firing. Moreover, since it is assumed that it is fired by superheated steam activated more than normal superheated steam by contacting with the reducing far-infrared radiation material, there is a possibility that it has special functional performance. . Note that shell ash that has been ashed in particulate form has the feature that it can retain air.

  When this particulate shell ash was put in water, the measured value of the pH meter showed about 13.0, but the pH test paper showed a color of pH 10 to 11, and the oxidation-reduction potential was -90 mV (vs. . Ag-AgCl).

  In addition to these uses, lithium can be added as a constituent component to the functional porous ceramic of the present invention. It is also possible to add lithium oxide up to about 5 to 10 mol% instead of the alkali metal sodium oxide and potassium oxide added to the raw material. A continuous porous ceramic containing a high concentration of lithium and developing micropores is also expected as an electrode material for a high-performance lithium ion battery.

  Up to this point, the technology for producing porous ceramics using high-temperature superheated steam at 700 ° C. or higher has been described, but superheated steam is, for example, sulfuric acid of a sulfuric acid compound added to a ceramic raw material in the temperature range of 300 ° C. to 700 ° C. It is effective for the method of leaving the group in an appropriate hydration state, and it is considered that it can be used for the purpose of forming a superacid point in the solid acid catalyst of ceramics and inorganic compounds.

  In addition to these methods of using superheated steam, the high-temperature superheated steam generator and high-temperature superheated steam calcination furnace capable of using high-temperature superheated steam of 300 ° C. or higher according to the present invention provide a novel high-temperature superheated steam calcination technology. It can be used for the purpose of developing various unique functional materials. For example, Patent Document 15 “Manufacturing of ultra-high specific surface area activated carbon” is one in which activated carbon having an ultra-high specific surface area is manufactured by a high-frequency superheating method. There is a possibility that the superheated steam is further activated by coming into contact with the functional porous ceramic and promotes the rate of increase in the specific surface area of the activated carbon.

  In order to produce activated carbon with an ultra-high specific surface area, it is necessary to control the temperature of superheated steam fairly precisely. That is, it is necessary to devise a technique for keeping the volume space where charcoal in contact with the superheated steam is constant and keeping the temperature constant. The far-infrared radiant ceramics-type superheated steam furnace is relatively easy to control the temperature of superheated steam in contact with charcoal, and can be used for large-scale and mass production.

  It can also be used for simple reprocessing activation of activated carbon that has been used for water purification. In addition, when oyster shells are incinerated with superheated steam at 500 ° C to 900 ° C, particulate and porous shell ash can be produced, so waste oyster shells, scallop shells, oyster shells, etc. can be used as useful agricultural materials and It can be easily converted into environmental conservation materials.

  As described above, it has also been shown that the far-infrared specification superheated steam generator and superheated steam calciner used for the production of porous functional ceramics can be used in various fields. For example, a far-infrared superheated steam calciner used for the production of porous functional ceramics can be used for the production of high-performance activated carbon, the production of lime derived from shells, and the like.

  Examples will be described below. FIG. 10 is a process diagram showing a method for producing a functional porous ceramic according to an embodiment of the present invention. First, as an outline, in the present invention, in the raw material pulverization and mixing step S1, activated carbon, rock pulverized material, limonite, bone ash, and other raw material components are sufficiently finely pulverized and mixed using a ball mill.

  The activated carbon used as the raw material includes organic carbides such as charcoal, bamboo charcoal, coffee charcoal, coconut husk charcoal, coal coke, and petroleum coke, preferably activated carbon having a large specific surface area derived from coconut husk charcoal, bamboo charcoal, and coffee charcoal. Is used. As the crushed rock, granite, volcanic rock, barley stone, and other various crushed rocks, or crushed mud from a crushed stone factory are used. Preferably, crushed rocks having excellent far-infrared radiation performance are used.

  In addition, ceramic materials that can supply silicic acid content such as clay, super clay, bentonite, feldspar, kaolin and alumina in the raw material instead of rocks, or chemicals such as silicon compounds such as silicon carbide and aluminum compounds It is also possible to adjust the chemical composition of the ceramic raw material mixture by combining the materials.

  Limonite is a soil containing about 80% by weight of iron oxide produced in the Aso region of Kyushu, and is used to supply iron in ceramics. If iron is present in the skeleton of the porous ceramic, the iron atom may change between divalent iron and trivalent iron, and may exhibit redox performance. In the present invention, this limonite is preferably used, but other materials containing iron oxide can be substituted.

  Bone ash is composed mainly of phosphoric acid and calcium. In the present invention, bone ash is added as a component for developing a porous structure in ceramics as in Patent Documents 33 and 34. Bone ash can also be replaced with the chemical reagent hydroxyapatite, other phosphoric acid and calcium compounds, or phosphoric acid or phosphate.

  Calcium carbonate is used as the calcium compound, but shell ash such as oyster shells and scallops, and chemical calcium compounds may be used. In addition to these basic raw material compositions, metals are combined and added as necessary. Metals are used by being added to the raw material mixture for the purpose of imparting catalytic strength to the ceramic and strengthening it, and for the purpose of forming a magnetic substance in the ceramic.

For the purpose of enhancing the catalytic performance, zirconium, silver, palladium, gold, platinum, etc., which are used for many catalysts and are clearly known to enhance the catalyst performance, are used in combination as necessary.
Further, in the production process of the present invention, the ceramic after the primary firing is markedly magnetized and is attracted to the magnet. However, depending on the temperature of the secondary firing, a ceramic that has lost the magnetism is also produced.

  The cause of the change in magnetism cannot be determined at this time, but it is possible that the magnetic crystals produced in the ceramics will exhibit functions, so it is possible to form a magnetic body by combining with iron atoms of iron oxide. Use a combination of compatible metals. In the present invention, manganese, titanium, tungsten, yttrium, cerium, neodymium, or the like is used as a metal having the possibility of forming a magnetic compound such as a spinel structure by combining with iron atoms in iron oxide. There are many metal elements that form a magnetic substance with iron atoms, and the present invention is not limited to these elements.

  The pulverizing and mixing step of S1 can be carried out by a wet or dry process, but a wet method that is presumed to easily form a compound in an aqueous solution during pulverization and mixing is preferred. Add 70% and grind and mix. In the dehydration step of S2, water in the pulverized mixture of raw materials is removed, but air drying or hot air drying is preferable to prevent raw material components dissolved in water from entering the filtrate by filtration. It does not exclude the dehydration method. In the pulverization and mixing by the dry method, the dehydration step of S2 is not necessary.

  In the humidity conditioning / degassing step of S3, the pulverized raw material mixture dehydrated by the wet method is sufficiently kneaded to remove bubbles and homogenize the mixture. On the other hand, the raw material mixture pulverized and mixed in a dry process is kneaded by adding water until the mixture becomes clay. In addition, the pulverized mixture of raw materials can be pulverized after being sufficiently dried by a drier or the like, and can be subjected to round ball molding or high-pressure press molding from a powder state.

Unlike the firing of general ceramic products, the ceramics of the present invention are porous and air permeable, so moisture, bubbles, CO ₂ derived from charcoal, etc. contained in raw materials and molded products before firing expand during firing. And will not rupture. That is, since the generated gas or the expanding gas can be discharged to the outside through the pores, deaeration is not always necessary and can be omitted.

  The operation of the molding / drying step of S4 can be processed into various shapes by press molding using a mold, molding by a gypsum mold, or the like. Further, it can be formed into a spherical shape with a commercially available round ball processing machine or the like from a powder state, or processed into a plate shape or other various shapes by high pressure press molding. The drying step after molding is usually sufficiently dried by air drying to remove moisture, but drying with superheated steam at a temperature of 300 ° C. or lower is also possible.

  The ceramic firing process of the present invention is performed using a primary firing process in which a general electric furnace or a gas furnace in steps S6 to S8 is used and a superheated steam furnace in a high temperature range of 300 ° C. or higher. It consists of the secondary baking process of S11-S12. In the primary firing process of S6 to S8, a ceramic container-shaped firing sheath is used, and in the firing preparation step of S5, the molded product stored in the firing sheath is placed so as to be covered with charcoal particles, and is small for degassing. Cover with a hole.

  At this time, the particulate charcoal used for filling is preferably coconut shell charcoal having a diameter of about 1 to 2 mm. When fired in this manner, combustion and burning of the fine carbon powder added to the ceramic raw material is prevented, and the fine carbon powder and the carbon derived from charcoal are fired into porous ceramics.

  The maximum temperature of the heating and holding step of S7 following the preheating step of S6 is set to 1300 ° C. or lower, and preferably held at a temperature of about 1150 ° C. to 1300 ° C. for about several hours to 24 hours. And after heating and holding, after cooling in the slow cooling process of S8, it takes out from a heat-resistant container by S9, isolate | separates a molding and charcoal, and separates and removes the powdered charcoal used for filling. In the secondary firing preparation step of S10, the ceramic separated from the powdered charcoal is stored in a heat-resistant container having punched holes so that water vapor enters the lower portion, and subjected to firing with superheated steam in a high temperature region in the overheating holding step of S11. , S12 is gradually cooled in the slow cooling step. Furthermore, a functional porous ceramic is obtained in S15 through a cooling process in S13 and a washing / drying process in S14.

The baking process of S11-S12 is performed using the high temperature superheated steam baking furnace shown in FIG. The flow rate of the saturated water vapor introduced into the superheated steam generation unit is set to 30 g / min to 200 g / min, preferably 75 g / min to 125 g / min. When indicating this flow at a flow rate per unit cross-sectional area, the pipe portion of the superheated steam generating furnaces are approximate flow rate of 1.5 g / min ^/ cm 2 ^{~10.2g /} min / cm ^2, the sample of the superheated steam calciner in the container portion are approximate flow rate of 0.2 g / min ^/ cm 2 to 1.2 g / min / cm ^2, preferably each, 3.8 g in the pipe portion of the superheated steam generating furnaces / min ^/ cm 2 ^~6.4g / min / cm ^2, is in the sample container portion of the superheated steam baking oven with 0.4 g / min ^/ cm 2 ^{~0.75g /} min / cm ^2. The flow rate of water vapor can be obtained by introducing saturated water vapor to be introduced into water of known weight and cooling, and measuring the weight increase per hour.

  A preferable temperature for firing the charcoal composite porous ceramics with superheated steam is 700 ° C. to 900 ° C., and the firing is performed at that temperature for about 1 to 24 hours. At this time, it is confirmed with a unique odor that the sulfate group derived from the raw material compound in the ceramic is eliminated as sulfurous acid gas. Therefore, it is clear that the sulfate group remains without being decomposed by primary firing at about 1300 ° C. in charcoal.

  From this, it is considered good to use superheated steam at a temperature between 300 ° C. and 700 ° C. where the sulfuric acid remains, for example, when aiming to form a super strong acid by leaving a sulfate group or the like in the ceramic, but the remaining form is not certain. . In addition, when generation of sulfurous acid gas becomes a problem, carbonate is used as a raw material instead of sulfate.

(material)
Next, specific examples of raw materials are shown. As the charcoal mixed with the raw material, activated carbon having a specific surface area of 500 m ² / g or more manufactured from the cheapest coconut shell charcoal at the present time was used. The crushed rocks are granodiorite called Iwate's chlorite, andesite called Itokawa's Tomuro stone, crushed mud from a crushed stone factory in Hiyokage-cho, Miyazaki, and Each barley stone was used after analyzing its chemical composition.

  Table 5 shows the chemical composition of each major component by weight, Table 5 shows the chemical composition of granite from Iwate Prefecture, Table 6 shows the chemical composition of Tomuro stone from Ishikawa Prefecture, and Table 7 shows the product from Hinokage-cho, Miyazaki Prefecture. Table 8 shows the chemical composition of the crushed stone mud, and Table 8 shows the chemical composition of the Chinese barley stone.

The content of iron oxide (Fe ₂ O ₃ ) in these pulverized rocks was 0.01 to 0.06 by weight as shown in Tables 5 to 8. Therefore, the total chemical composition of ceramic raw materials is adjusted by adding iron oxide, triiron tetroxide (magnetite), or iron oxide-containing natural soil to the raw material composition so that the iron oxide content is 3 to 6 mole percent. did.

  As for the natural soil containing iron oxide, the soil called limonite produced in the Aso region of Kumamoto Prefecture was used. The chemical composition is shown in Table 9.

As bone ash, a commercially available product having a chemical composition adjusted under the trade name of flat bone ash was used. Table 10 shows the chemical composition of the flat bone ash. Bone ash is composed of calcium oxide and phosphoric acid, and the phosphoric acid content in the composition of the raw material mixture of the present invention is supplied as bone ash, and the contained calcium oxide content is added to the added amount of calcium as the calcium content contained in bone ash.

  The calcium compound is preferably a chemical, calcium carbonate, but can be replaced by shell ash such as oyster shell, scallop or other calcium compounds. For oyster shells and scallop shells, it is preferable to use shell ash incinerated with high-temperature superheated steam. Table 11 shows the chemical composition when the oyster shell was incinerated with high-temperature superheated steam. Oyster husk ash contains about 94% calcium oxide by weight percent of the oxide composition.

  In addition to these basic raw material compositions, metals were added in combination as needed. As the metals, water-soluble salts such as manganese, titanium, tungsten, yttrium, cerium, neodymium, zirconium, silver, and palladium were mainly used, and gold and platinum were also used in combination. As for gold, a glass having a lithium borosilicate composition and containing gold as colloidal fine particles with a gold concentration of about 0.002 weight percent was added. Table 12 shows the chemical composition of colloidal gold glass.

(Raw material composition)
Below, the specific example of a raw material compounding composition is shown. The substance names indicated by element symbols in the raw material composition are shown in Table 13.

The colloidal gold glass in Table 12B contains gold as colloidal particles in an amount of 0.002 weight percent in a glassy lithium borosilicate composition.

  As mentioned above, the compounding example about a typical raw material composition was shown, and the total chemical composition of the ceramic raw material calculated | required by integrating | accumulating a content component from the chemical composition of each raw material in an Example was shown by the mole percent composition.

When showing the preferred composition range of the major chemical components can be produced superheated steam fired functional ceramics of the present invention in mole _{percent, SiO 2: 40~60%, Al} 2 O 3: 15~30%, CaO: 5~20 _{%, MgO: 1~20%, Na} 2 O: 1~10%, K 2 O: 1~10%, Fe 2 O 3: 2~10%, P 2 O 5: 0.01~5.0% _{, TiO 2: 0~10%, MnO} 2: a composition range of 0 to 5.0%, can be used a number of natural materials if you can fit into the composition range as a starting material.

However, when the Al ₂ O ₃ content is 20 mol% or less, it is necessary to perform primary firing at a temperature of 1200 ° C. or less. When primary firing is performed at a temperature of 1200 ° C. or higher for a composition having an Al ₂ O ₃ content of 20 mol% or less, the ceramic is softened and deformed. Although this softening temperature is estimated to decrease mainly in relation to the iron oxide content, the interrelationship is not clear at this time. When the composition is adjusted so that the content of Al ₂ O ₃ is in the range of 20 to 30 mol%, the composition can be fired at a temperature of about 1300 ° C. even if the content of iron oxide is 5 mol%.

Moreover, 0-5 mol% of ZrO ₂ can be added for the purpose of functional enhancement and durability enhancement, and functional enhancements such as redox performance, various catalyst performance, far-infrared radiation performance, and negative ion generation function. For the purpose of the above, elements that can form magnetic compounds with iron elements, elements that can form non-stoichiometric oxides, and rare earth elements, and noble metal elements that form fine particles to enhance the catalytic function Kinds of elements can also be added.

  The amount of each element added is 0 to 5.0 mol% of boron oxide, and metal elements such as chromium, cobalt, nickel, copper, zinc, germanium, yttrium, molybdenum, tin, antimony, tungsten, bismuth, And, for rare earth metals such as lanthanum, cerium, neodymium, praseodymium, samarium, europium, gadolinium, erbium, etc., it is about 0-2.5 mol%, respectively, and for noble metal elements such as gold, silver, palladium, etc. About 0.5 mol%.

  Lithium can also be added, and 0 to 10 mol% of lithium oxide can be added in place of alkali metals sodium and potassium. On the other hand, the amount of charcoal or activated carbon added to the raw material is 1.0 to 25% by weight percent, preferably 10.0 to 15.0%, based on the weight of the raw material blend.

  INDUSTRIAL APPLICABILITY The present invention can be used for porous functional ceramics exhibiting oxidation-reduction performance and far-infrared radiation, a method for producing the same, and a superheated steam generation furnace and a superheated steam firing furnace with a far-infrared radiation material specification. The porous ceramics containing carbon can be secondarily fired using superheated steam in the region and used for the production of functional porous ceramics.

  The produced porous ceramic is a functional porous ceramic having excellent reducibility and has high far-infrared radiation performance. Using this functional porous ceramic, it can be used in a technique for producing ceramic reduced water having a pH value and oxidation-reduction potential similar to electrolytically reduced water.

  In addition, using a functional material with far-infrared radiation performance as a steam superheating medium in a high-temperature superheated steam firing furnace, it also produces activated carbon with a high specific surface area and shell ash with a calcium carbonate and calcium hydroxide composition. Can be used.

DESCRIPTION OF SYMBOLS 11 Boiler 13 Piping 15 Heat-resistant steel 17 1st heating furnace 19 2nd heating furnace 20 Superheated steam baking furnace 21 Sample container 23 Outer cylinder 25, 27, 29 Annular furnace

Claims (9)

A primary firing step of firing a ceramic material containing charcoal and iron oxide;
A method for producing a functional ceramic, further comprising secondary firing in which the ceramic material fired in the primary firing step is fired with superheated steam in a temperature range of 700 ° C to 900 ° C. Rock pulverized product, ceramic raw material containing silicic acid and alumina, a silicon compound, aluminum compound, method of manufacturing a functional ceramic according to claim 1, wherein at least one of Kaihai comprising the step of creating the ceramic material.   The method for producing a functional ceramic according to claim 1, wherein the ceramic material includes at least one of charcoal, bamboo charcoal, coffee charcoal, coconut shell charcoal, coal coke, and petroleum coke as the charcoal.   4. The production of the functional ceramic according to claim 1, wherein the ceramic material includes at least one of zirconium, silver, palladium, gold, platinum, manganese, titanium, tungsten, yttrium, cerium, and neodymium. Method. The primary firing process, method for producing a functional ceramic according to any one of claims 1 to 4 carried out at a temperature ranging from 1150 ° C. to 1300 ° C.. The secondary sintering step, method for producing a functional ceramic according to any one of claims 1 to 5 carried out for 1 to 24 hours. The method for producing a functional ceramic according to any one of claims 1 to 6 , wherein in the primary firing step, the ceramic material molding is covered with charcoal particles and accommodated in a firing sheath. A superheated steam generator for providing superheated steam for use in the method for producing a functional ceramic according to any one of claims 1 to 7 , wherein a tube filled with ceramic particles therein, and the tube from outside A superheated steam generator for generating superheated steam by introducing saturated steam into the tube and heating the ceramic particles maintained at a predetermined temperature. A superheated steam firing furnace used in the method for producing a functional ceramic according to any one of claims 1 to 7 , wherein a tubular portion for storing a container of a sample to be fired therein is provided at a lower portion of the tubular portion. A steam heating unit that superheats steam to supply the cylinder part to the cylinder part, and a heating part that heats the cylinder part and the steam heating part from the outside, and the steam heating part is an overheat supplied from outside A superheated steam firing furnace in which a flow path for guiding water vapor to the cylindrical portion is formed, ceramic particles are filled therein, and the superheated steam is heated by the ceramic particles maintained at a predetermined temperature.