JP2005097082A - Method of firing ceramics at low temperature and ceramics fired at low temperature - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of recycling and firing at a low temperature of waste ceramics. <P>SOLUTION: The method comprises a first process wherein waste ceramics are dry-ground to pass through a ≤350 mesh-screen, a second process wherein the dry-ground product is wet-ground to be about a few μm, a third process wherein an additive lowering the melting point comprising a plasticizer based on a natural clay and glass or the like is added and mixed, a fourth process wherein the mixed product is shaped, and a fifth process wherein the shaped product is fired at a low temperature of ≤about 1,150°C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to the ceramic industry and technology.

  Porcelain and porcelain are mainly composed of feldspar, silica and clay. In the case of pottery, the ratio of feldspar plus silica and clay is 2: 3. In the case of porcelain, the ratio is 3: 2, and the firing temperature is approximately 800. It has been set to about 1300 ° C. or higher. The clay mineral is dehydrated by the adsorbed water adsorbed to the surroundings at a temperature of 100 ° C. to 200 ° C., forms kaolinite crystals at 500 to 600 ° C., and the hydroxyl group (OH) bonded with Si and Al is crystallized. The kaolinite is replaced by an amorphous metal called metakaolin.

At 1300 ° C., this metakaolin is also destroyed, becoming γ-alumina (γAl ₂ O ₃ ) and mullite (3Al ₂ O ₃ · 2SiO ₂ ), and silicon dioxide and silica sand (both SiO ₂ ) are added to the feldspar. The glass is vitrified and the glass is bonded to the crystals of γ-alumina and mullite, making a hard and strong ceramic. This is the normal mechanism of ceramic production. However, they are vulnerable to blows caused by falling or touching each other.

  However, the tableware most used in everyday homes has many opportunities for mutual contact and dropping, and often breaks. By the way, it is reported that half of the weight of non-combustible waste (iron, ceramics, plastics, etc.) discarded from Japanese households is this ceramic. This incombustible waste is disposed of at the final disposal site for waste, and now this final disposal site is also a social problem due to its limited residual disposal capacity.

  Therefore, an attempt was made to recycle and use these discarded ceramics, and "New potential for recycling ceramic products (LCA evaluation)-Environmental impact in recycling porcelain tableware" ("Ceramic Data Book 2000, separate print). "Issuance / Industrial Product Technology Association <Techno Plaza>).

Ceramics made from clay minerals with good plasticity can be easily made into various shapes, but in order to be completed as ceramics, they must be fired at a high temperature of 1300 ° C, and the energy cost consumed there. In addition, the impact on the global environment due to CO ₂ emissions could not be ignored.

  In addition, when firing at 1300 ° C., even if primary colors such as red, green, and yellow are produced as glazes, the primary colors fly out and it is difficult to produce such shades as a so-called sketch.

  Ceramics made using a lot of energy are also vulnerable to breakage, and because they are easy to break and the cracked pieces are discarded as they are, they have also caused new environmental problems such as disposal sites.

  In the previous report of the ceramic data book, etc., attempts have been made to recycle the non-standard pique products produced by companies and the waste ceramics collected after use at the antenna shop. In this method, a pique product is roughly pulverized to several mm and then wet pulverized by a ball mill. Even if it is a peke product, it has been fired once at 1300 ° C. or higher, so that it should be able to be fired at a low temperature the next time it is recycled. However, according to the report, the re-baking temperature is 1280 ° C., and the merit in terms of energy using the pique product is not so much visible. Also, when reusing discarded ceramics such as piques, the recycling rate was reduced to less than 20%, and recycled products were made by mixing 30% clay, 20% silica, and 20% feldspar. It was reported. It is not a very efficient recycling method.

  In order to test this problem, the waste ceramics containing pique products were pulverized with a ball mill of a wet pulverizer, and reusable products were made by the method described in the report. In order to obtain a predetermined particle size (10 μm or less) using a ball mill, it is necessary to operate the ball mill for nearly 24 hours. The reexamination proved important. It was found that even in waste ceramics fired once and made into porcelain, the soda content was eluted with alkali when wet pulverized for that amount of time, and as a result, the mud partially solidified and so-called stale. Further, it has been found that the melting point rises due to the outflow of soda, and the glass is vitrified and does not become so-called porcelain unless the firing temperature is raised to the level of ordinary ceramics (1300 ° C.).

In other words, under the existing waste disposal system and the existing recycling technology for waste ceramics, the waste ceramics that were damaged or turned into piques had the following problems.
(1) The recycling rate of discarded ceramics was as low as about 20%. This made it possible to produce a recycled product 5 times the amount of ceramics discarded. Normally, the Eco Mark assumes that the waste products are reused by 50% or more. Otherwise, the collected waste products are not reused and are piled up as waste.
(2) The characteristics of using waste ceramics and low-temperature firing have not been established. Ceramics baked at 1300 ° C. and crystallized not only to clay but also feldspar and silica (so-called porcelain) are individual pulverized powders even when pulverized. Therefore, if this feature is utilized, low-temperature firing was possible.
In spite of these problems, it has not been established as a technology for the circulation of commodity economy for recycling.

  The problems described above have been derived from problems in manufacturing technology so far. For example, waste ceramics are only a few mm in size when pulverized using a jaw crusher or roll crusher used for pulverization in the conventional ceramic industry. In order to reduce this to a level of several μm with a wet pulverizer such as a ball mill, it takes about 10 hours to 1 day. However, when it is applied to the wet pulverizer for this amount of time, the alkaline content is eluted from the waste ceramics, causing the pulverized powder to harden. When it was turned by hand, the soil became rough and it was not possible to cast smoothly during casting.

  Increasing the reuse rate of waste ceramics made the dusting and hand casting problems more prominent. In addition, waste ceramics that have been burned with glaze have been used in the past when heavy metals such as lead are mixed in the glaze. When recycling waste ceramics, there is a risk of such contamination. Therefore, it was a challenge to remove such mixed materials. In addition, when impurities are mixed in this way, the background of the soil becomes a cloudy white background, and there is a problem that the purpose of use is limited.

Means to solve the problem

  Therefore, in the present invention, a system that can be recycled and reused by about 50% or more of discarded ceramics and adapted to market economic distribution is considered. Therefore, we decided to solve the two problems in manufacturing technology, the problem of pulverized powder becoming hardened due to alkali elution, and the problem of lack of plasticity and poor moldability. We decided to recycle and re-use commercialized ceramics and so-called waste ceramics that became non-standard peked products by dry pulverization to a particle size of # 350 mesh or less, about 10 μm to 20 μm. A plastic additive was added to facilitate molding. As the plastic additive, natural clay was used as a raw material, and this was applied to a centrifugal separator such as a decanter to remove silica sand and the like, and the plastic part was taken out with high density.

In addition, CO ₂ reduction, CO ₂ tax, etc. are issues in the real world. In the market economy, in order to continue production using a firing furnace, it is important to produce ceramics by low-temperature firing to avoid an increase in cost. Therefore, what was once made as ceramics receives energy at the firing stage, changes the composition structure, and so-called porcelain, so when reusing, pay attention to that point, approximately 1150 ° C, low-temperature firing in so-called ceramics I thought about re-commercialization.

  In order to enable low-temperature firing, the present application focuses on the firing mechanism of ceramics and considers that high-temperature firing at approximately 1300 ° C. is necessary when crystallizing the silica, and as a newly added material, silica In addition, a low melting point additive made of glass, soda feldspar or the like was added in consideration of crystallization of clay at 1150 ° C. or lower.

  FIG. 7 is a diagram illustrating heating of a clay earthenware made of clay, feldspar, and quartzite at temperatures of 200 ° C., 400 ° C., 600 ° C., 800 ° C., 1000 ° C., 1200 ° C., 1300 ° C., 1400 ° C., and 1600 ° C. It is the figure which examined by X-ray analysis how the ground soil is changing at the time. (From "Seto ware 1300 tradition and technology")

What can be understood from this analysis chart is as follows.
(1) The one heated at 200 ° C. and 400 ° C. is not different from the unheated base soil. Don't be a ceramic when heated at 400 ° C.
{Circle around (2)} When heated at 600 ° C., peaks at diffraction angles of 12 degrees and around 24 degrees indicating clay are reduced, and a part of the clay is decomposed by heating. However, feldspar and quartz have not changed. 600 degrees Celsius is considered to be the temperature at the border of ceramic ware.
(3) When heated at 800 ° C., the peak indicating clay disappears and feldspar and silica do not change. Pottery-pottery can be made at this temperature.
(4) When heated at 1000 ° C., the peak around 27 degrees indicating feldspar is small, indicating that feldspar begins to melt at this temperature.
(5) In the case of heating to 1200 ° C., the peak indicating feldspar disappears, and the background indicating the glass phase is slightly raised instead. Ceramics-When ceramics reach this temperature, clay, feldspar, and silica react with each other, and mullite crystals and glass, the final structure of ceramics, begin to form.
{Circle around (6)} When heated to 1300 ° C., it can be seen that the silica is gradually dissolved and mullite is further generated.

Moreover, it can be said as follows when the photograph of the firing surface by an electron microscope, the data on the weight loss analysis, the differential thermal analysis, and the thermal expansion measurement are taken into consideration.
(1) Clay decomposes at 400-600 ° C and changes to a substance that does not return to clay even when water is added.
(2) The feldspar hardly changes up to 800 ° C., starts to melt when heated to 1000 ° C., melts when heated to 1200 ° C., reacts with the surroundings to form a glass phase, and enhances the reaction of the ceramic.
(3) Silica reacts with feldspar at around 1200 ° C and starts to melt slightly, and almost melts up to 1400 ° C. When baked at 1300 ° C., mullite and glass phase develop and become ceramic.

    Ceramics need clay for plasticity and moldability, feldspar contains potassium and sodium that dissolve clay and silica, helping to generate crystallization and mullite, and the remaining silica plays the role of aggregate. To increase the strength of ceramics. In the case of recycled ceramics using waste ceramic ground powder, this ground powder once fired at 1300 ° C to become porcelain is the base, so clay as a plastic additive that binds this ground powder and vitrification of this clay For this purpose, glass or soda feldspar as a low melting point additive is required, but the pulverized powder itself serves as an aggregate instead of silica. When this silica stone was contained, it had to be heated to 1200 ° C. or higher to make mullite and ensure the strength of the ceramic. However, if the silica is removed, it can be made into ceramic by firing at a low temperature.

  The establishment of such a re-commercialization technology for discarded ceramics is the first object of the present invention. If a waste disposal system that collects and stores waste ceramics for reuse as resources, rather than disposing of waste ceramics as waste in municipalities, recycle waste ceramics on the condition of the re-commercialization technology according to the present invention. It can be commercialized.

  In addition, the second purpose is to make the ceramics made by re-commercializing the discarded ceramics safe and without the heavy metal or the like, and to make the ceramics white. In the present invention, for this second purpose, magnetic separation technology is used to remove impurities such as lead as well as iron from the pulverized powder of waste ceramics.

  The magnetic separation technique is also disclosed in Japanese Patent Publication No. 53-44260. Every substance is more or less magnetic in a magnetic field. The principle of magnetic separation, which captures and removes the magnetic particles by the magnetic force of a magnet (electromagnet), was introduced over 30 years ago in British Nature magazines, but ferromagnetic iron and nickel, In order to separate and remove not only cobalt but also weak magnetism and non-magnetism, a strong magnetic force is required, and in order to generate the electromagnetic force, much power consumption and heat generation have been problems until now. It was. Also, several improved patents have been issued in a form that solves the problems that have arisen in putting the magnetic separation technique shown in Japanese Patent Publication No. 53-44260 into practical use. For example, Japanese Examined Patent Publication No. 56-30049 uses a flocculant to remove non-magnetic substances that cannot be removed together with magnetic substances. Japanese Examined Patent Publication No. Sho 59-49044 with a magnetic filter made in the form of a wire mesh and arranged so as to be perpendicular to the magnetic field. Japanese Patent Publication No. 60-49006, which allows the backwashing to be performed efficiently by flowing water containing fine particles having a zeta potential opposite to that of the fine particles in the raw water.

  However, despite these improvements, the magnetic separation technique has left many practical problems, and the superconducting method is the only method left to improve the separation accuracy. However, it had the problem of enormous amounts of money for research and development and equipment costs. The present invention intends to achieve the object while solving these problems. As three elements of the magnetic force acting on the particles, (1) the volume of the particles, (2) the magnetic difference between the particles and the dispersion medium, and (3) the magnetic gradient are known.

  Therefore, in the present application, in order to make the volume of (1) particles as small as possible, the dry pulverized one is further wet pulverized into fine particles. However, since alkali is eluted when wet pulverized for a long time, it was suppressed in about several hours. Even so, it was made fine by dry pulverization beforehand, so it became possible to make it finer.

  (2) In order to maintain the magnetic difference between the particles to be removed by magnetic separation and the base dispersion medium, a plurality of magnetic force divisions are provided so that the electromagnetic force gradually proceeds from weak to strong. Removed iron, nickel, cobalt, etc. that can be removed even if the electromagnetic force is weak, and finally devised a non-magnetic material with a strong force.

  (3) In order to create a magnetic gradient, a projection type paramagnetic member was used, and the magnetic gradient at the projection was increased so that even a non-magnetic material could be removed with a relatively weak electromagnetic force.

  And in order for all of these to work well, the mechanical system is divided into two systems, that is, two systems, one of which is magnetized to exhibit the removal function, while the other is demagnetized, and the attached object is actually It has been removed. These were used alternately to avoid slowing the separation performance due to the adhesion of deposits.

The invention's effect

  As described above, according to the present invention, waste ceramics such as tableware and flower vases have been discarded as garbage and recycled as products that have been reused as waste. There was no system for separate collection and storage as recyclable items. (2) Waste ceramics were pulverized by dry pulverization and wet pulverization in the conventional soil-making industry, but in dry pulverization, only up to several millimeters were pulverized, and wet pulverization took over 10 μm over a long time. I've been crushed. However, when wet grinding is used for a long time, once fired, the soda content will flow out due to alkali elution, making it difficult to make soil with the ground soil, and the characteristic that the melting point is low can be lost. There was also a problem in that it was difficult to remove harmful heavy metals used in the old glaze contained in the discarded ceramics.

  ▲ 1 ▼ In municipalities responsible for general waste from households and local small-scale business entities, a system for separating and collecting waste ceramics as resources and collecting them together with pique products from the enterprise is created. 2 ▼ Using a dry mill such as a roller mill, which has been used as an industrial material material in the mining industry, finely pulverize the collected waste ceramics, and (3) devising plastic additives and low melting point additives, Combining this with the earth making (kneading), molding, and baking business for making earthen clay in the original ceramic industry, producing ceramics such as tableware and flower vase by low temperature baking using waste ceramics, and harmful by high gradient magnetic separation device A technology to remove heavy metals was proposed.

  If ceramic production is carried out using the method according to the present invention, it becomes possible to recycle discarded ceramics, and (1) it is given to the environment such as destroying nature in order to secure a disposal site by treating and disposing of it as waste. (2) Characteristics of waste ceramics, energy once made porcelain is used efficiently, and what was previously not possible to be fired porcelain at 1300 ° C or higher can be obtained by low-temperature firing at 1150 ° C or lower. It can be made into porcelain. (3) In addition, glazes can be used glazes made of copper, zinc, selenium, etc. whose color has almost disappeared at 1300 ° C, producing green, yellow and colorful red colors. I can do it now.

  The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a low-temperature firing method according to claim 1 of the present invention. (2) is a discarded ceramic, (4) is a ceramic raw material to be added, (6) is a dry grinding process, (8) is water, (10) is a plastic additive, (12) is a low melting point additive, (14 ) Is a kneading step, (16) is a molding step, and (18) is a low-temperature firing step.

  Currently, discarded ceramics are once used at home, and most of the damaged ones are collected by non-combustible waste collection by municipalities and disposed of in final disposal sites. In addition, non-standard products discharged in the manufacturing process are several percent within the range of production fractionation, but in most cases they are also discarded. On the other hand, municipalities, such as bottles and cans, recently collect plastic bottles, white trays, and other waste plastics as separate resources and use them on their own re-commercialization routes.

  First of all, the municipalities responsible for collection and disposal of so-called general waste from households create a system to separate and collect waste ceramics from homes as resources, not as non-burnable waste. Recycling of bottles and cans has already been done in many places. Some bottles are separated and sorted according to color and size, and they are collected. However, if this waste ceramic is also separated from white and colored, it can be used for later processing. More convenient above.

  In this way, waste ceramics (2) that have been baked at 1300 ° C or more and made porcelain once collected as waste ceramics collected separately in municipalities and pique goods collected from various ceramic manufacturers. When the manufacturing site that performs re-commercialization by low-temperature firing and the municipalities that collect the waste ceramics are separated from each other, the municipalities store them and transport them in large quantities.

  Waste ceramics are made into porcelain with vitrification by firing once. Therefore, even if it is made into a powder, each powder body is made porcelain, but as a whole it loses some energy in the sense that it retains its shape by becoming a powder. In order to make a ceramic product, it is necessary to mold these powders while bonding them, fire the bonded body anew, and perform porcelain including recrystallization again. As explained earlier, waste ceramics were originally made from clay, feldspar, and silica. As the firing temperature of kaolinite in the clay increases, it becomes γ-aluminum and mullite instead of metakaolin. Is formed by vitrification and bonding (so-called porcelainization). Therefore, in order to recycle this waste ceramic, if there is a finely pulverized material, it will be sufficient if the material can be molded after being plasticized.

  However, if dry pulverization is performed, there is almost no alkali elution, but there is still a very small amount of elution. To compensate for this and to magnetize the clay, which is a powder combination, at a low melting point, Supply as raw material (4) to add feldspar.

  In the dry pulverization step (6), the waste ceramic is pulverized to a particle size of # 350 mesh or less, that is, an average level of 10 μm using a roller mill or the like. You may grind | pulverize to this level with dry mills other than a roller mill. Ideally, it is desirable to grind to a size of 7 to 10 μm. The fine powder of waste ceramics after pulverization is kneaded together with plastic additives (10) consisting of curdlan polysaccharides such as β-glucan and low melting point additives (12) such as glass and soda feldspar (sodium). In step (14), water (8) is added and kneaded.

  The plasticity of clay has been studied for a long time, and it has been found that curdlan-based polysaccharides such as β-glucan are involved in the study of artificial clay. Therefore, as one embodiment of the present invention, the fine powder was directly plasticized by introducing this polysaccharide which has established the plasticity of clay.

  The kneaded soil was molded into tableware or the like in the molding step (16), glazed with a low temperature glaze, and fired in a low temperature firing step (18) of 1150 ° C. or lower. At a high temperature of 1300 ° C or higher, the glaze will fly out of colors other than Fe, etc., and it was difficult to produce shades of green, blue, red, etc. using copper, zinc, selenium, etc. Glazing is also possible. Low temperature firing was made possible by the action of the low melting point additive (12) added in the kneading step (14).

  FIG. 2 is also a block diagram showing a specific embodiment corresponding to claims 1 and 2, which is an embodiment of the method for firing ceramics according to the present invention. In the block of the broken line portion, the same numbers as those in FIG. 1 indicate the same contents. (20) is a manufacturer or seller of ceramics, (22) is a non-standard pique, (26) is collected and stored, (28) is a municipality, (30) is recyclable, (32) is collected and stored, (34) is feldspar, (36) is a dry pulverizer, (38) is clay, (40) is a decanter, (42) is a highly plastic clay component, (44) is silica sand or glitter, and (46) is a kneading device. , (48) is magnesite, (50) is a molding apparatus, and (52) is a firing furnace.

  Waste ceramics, on the other hand, are used as a peculiar product (22) for companies that produce or sell ceramics (22), and on the other hand, they are recyclable resources (30) that are separated and collected and stored from municipalities. First, it is collected, transported and stored in a company having a dry grinding device (36) (26, 32). Here, the waste ceramics are pulverized to an average size of about 10 μm by a dry pulverization apparatus (36) such as a roller mill. On the other hand, the feldspar (34) for combining the pulverized materials and helping to make the regenerated ceramics porcelain may be pulverized by the dry pulverizer or together, or separately for convenience of production flow. May be. In any case, these crushers are owned by industries and companies that produce various raw materials by crushing minerals, but in order to store waste ceramics collected and operate dry crushers with loud sound, Installation conditions that consider the impact on the surrounding environment are required.

  Ceramics finely pulverized to an average level of 10 μm by a dry pulverizer (36) are made of solubilized magnesite as water (48) and low melting point additive (12) in a so-called kneading device (46) for making clay for ceramics. Knead together with powder (48) and plastic additive (10). Here, the clay (38) was decanted (40), and the mineral part (44) such as silica sand and glitter was taken out with a so-called centrifuge, and the highly plastic clay (42) was used as the plastic additive (10).

  Here, the feldspar (34) can be made of feldspar with high alkalinity such as soda feldspar, can serve as a low melting point additive (12), and can avoid the use of magnesite (48).

  The “soil” kneaded by the kneading device (46) was molded with the molding device (50) after removing moisture with a filter press or the like. The moldability was ensured even when the waste ceramic fine powder was "7" with "clay" in the ratio of "2". In addition, as shown in FIG. 3, four combinations of T-1 to T-4 were tested, but all of the moldability could be secured.

  What was shape | molded with the shaping | molding apparatus (50) was baked with the baking furnace (52). Specifically, as shown in FIG. 3, firing is performed at various furnace set temperatures, and T-1 to T-3 are set to 1120 ° C. or higher, and T-1 and T-3 are set to 1100 ° C. or higher. The porcelain was confirmed at the temperature. In the firing furnace, there is uneven distribution of temperature of about ± 50 ° C. depending on the location in the furnace, so that if porcelainization can be confirmed at 1100 ° C. or higher, it can be said that porcelainization by low temperature firing at 1150 ° C. could be confirmed. .

  FIG. 3 shows a test piece (T-1 to T-4) prepared by the low-temperature firing method according to the present invention and “Comparison C” as “Waste ceramic”, “feldspar”, “plastic additive (clay) as comparative test pieces. ”,“ Plastic additives (polysaccharides) ”,“ Low melting point additive (magnesite) ”,“ C soil-normal ceramic soil ”, changing the molding and firing temperature It is the result data which conducted the experiment of porcelain. The circles indicate that the porcelain has been confirmed.

  In addition to this, as a material to be added in FIG. 1 (4), glass powder obtained by using soda feldspar that also serves as a low melting point additive or by pulverizing a pique product from the optical fiber production process, Succeeded in making ceramic recycled products. For example, concretely, waste ceramic, soda feldspar or optical fiber pulverized product, and high plasticity clay extracted using a decanter or the like as a plastic additive are in a ratio of 50:15:35 or 60:10:30, respectively. And made a practical product. In addition, when the pulverized powder of the optical fiber was used, the original optical fiber itself was a tube system and included an air tube, so the weight of the finished ceramic could be reduced.

  FIG. 4 is a block diagram illustrating the invention according to claims 1 and 2, including claims and claim 5 according to the present invention. (60) is a waste ceramic, (62) is a dry grinding process, (64) is clay as a plastic additive, (66) is feldspar as a low melting point additive, and (68) is a wet grinding process such as a ball mill. , (70) is a high gradient magnetic separation process, (72) is a molding process, and (74) is a firing process.

  The block diagram of FIG. 4 is based on FIG. It takes 24 hours or more to grind the waste ceramic (60) to around 10 μm. In wet milling, due to moisture, when such time was spent, the alkali content was eluted and a staleness was produced, so substantial milling could not be performed. Then, it grind | pulverized once to about 10 micrometers in the dry-type grinding | pulverization process (62).

  In order to use as “soil” for re-commercialization of waste ceramics, a particle size finer than 10 μm is required. Further, in order to flow “soil” in the high gradient magnetic separation step (70), it is necessary to form a slurry containing moisture. Therefore, it was decided to pass the wet grinding process (68) after passing through the dry grinding process (62). If the wet pulverization step (68) is passed through for a long time, there is a concern that the alkali content may be dissolved out again, and the pulverized powder is suppressed to a few hours so as not to become sticky at the time of solidification or molding.

  In the high-gradient magnetic separation step (70), as such a separation apparatus, experiments were repeated in an experiment, and an apparatus suitable for a predetermined purpose was developed and used based on some ideas. As a result, in addition to heavy metals such as lead, impurities such as iron are also removed. After molding (72) and firing (74), the surface is inferior to that made of "earth" made of virgin raw materials. It became ceramic.

  Since the wet pulverization (68) here is a short time, the clay (64) and the feldspar (66) to be mixed are preliminarily singly wet or dry pulverized so as to be mixed with soil having the same conditions.

  The high gradient magnetic separator creates a high magnetic field by electromagnetic force, puts fine lines and mesh-like ferromagnets, creates a place with a high magnetic field gradient where the strength of the magnetic field changes greatly, and was placed in that magnetic field It is a technique that magnetizes even a so-called weak magnetic or non-magnetic substance and separates the substance from the base dispersion medium. Prof. Mitsuhiro Motokawa of Tohoku University's Institute for Materials Research has already succeeded in floating water by applying a magnetic force of 210,000 gauss using a super-power magnet.

  This technology is a technology that has attracted a great deal of attention in that sense because it can remove the polluted water, contaminated soil, and other pollutants by making them into fine powders and making them into a slurry. In order to generate it, power of 2000A, 400 kW level is necessary, and the cooling process of the heat generated with the power consumption and the power consumption is difficult. For this reason, development of super-power magnets has been indispensable. By making this a horizontal type, it is possible to produce even when force in the direction of gravity is not considered.

  FIG. 5 shows an embodiment of the high gradient magnetic separation apparatus used in the present invention. (80) is a raw material tank, (82) is a pump, (84) is a raw material valve, (86) is a magnetic separator, (88) is a filtration valve, (90) is a filtration raw material tank, (92) and (94) are rotary bearings, (96) is an oil tank, (98) is a pump, (100) is an oil cooler, and (102) is A magnetized material tank, (104) is a cooling / washing tank, (106) is a pump, (110) is a washing water valve, (112) is a blower, and (114) is a blower valve.

  The raw material (81) in the raw material tank (80) has been subjected to the wet pulverization (68) of FIG. 4 and is in the form of a slurry. Some of the waste ceramics were made before the regulation of the use of lead and other glazes, and these heavy metals are also included in the slurry materials. The raw material is sucked from the raw material tank (80) by the pump (82), and is passed through the magnetic separation part (86) through the raw material valve (84) serving as a check valve.

  In the magnetic separator (86), a cylindrical member (not shown) supported by the rotary bearings (92) and (94) is installed at the center, and the electromagnetic coil is installed around the cylindrical member to form a cylindrical shape. The sucked raw material (81) passes through the member, passes through the filtration valve (88), and is sent to the filtered raw material tank (90).

  Since the inside of this cylindrical member is installed so that it may become a high magnetic field with a magnetic coil, the particles in the raw material passing through it are made to be uniformly magnetized even if large or small. In addition, the cylindrical member is packed with a lot of small screws and operates as a magnetic body. As a result, a portion with a high magnetic field gradient is created at the tip of the screw thread or a member with a sharp thread, and this screw thread is positioned each time the cylindrical member supported by the rotary bearings (92) (94) rotates. In other words, the high magnetic field gradient portion changes its position in various ways.

  Therefore, while the raw material (81) passes through the cylindrical member, the particle portion in the raw material, including weak magnetic and non-magnetic ones, is magnetized on this screw and removed. What is stored in the filtration raw material tank (90) is a filtration raw material from which such particles have been removed.

  This magnetic separation is divided into five sections as shown in the figure so that independent electromagnetic coils can be operated. For example, originally ferromagnetic iron or nickel can be removed even if the magnetic field is weakened. Therefore, even when originally trying to remove a weakly magnetic or nonmagnetic material, such a ferromagnetic material is magnetized. However, if various things are magnetized, the sharpness of the pointed portion of the screw will be lost, and a high magnetic field gradient will not be possible. As a result, it will be difficult to remove materials that are originally weak or nonmagnetic. Therefore, the magnetic field created by the electromagnetic coils divided into multiple sections is made weak enough to obtain ferromagnetic materials in the first section, and ferromagnetic fields are taken, gradually increasing the magnetic field, and finally non-magnetic particles. Until it was magnetized.

  In this way, it was possible to magnetize and remove even weak magnetic lead and mixed non-magnetic cadmium. In order to make the ceramic background as white as possible, it is important to remove the iron, but when focusing on the iron in the ferromagnetic material and removing this iron in a single operation, the multiple sections are almost A method of making the magnetic field of the same level work and magnetizing and separating can also be considered.

  When the magnetic separator (86) is operated in this way, an electric current flows through the electromagnetic coil, and the magnetic separator (86) generates heat. A circulation pipe (not shown) was attached to the magnetic separator (86), and oil was allowed to flow through the pipe to take up this heat. The taken heat was cooled by the oil cooler (100) and circulated again by the pump (98). The oil cooler (100) feeds water from the cooling / washing water tank (104) with a pump (106) to cool the oil.

  FIG. 6 is an explanatory view for explaining the cleaning operation and the separation operation of the high gradient magnetic separation apparatus of FIG. FIG. 6 (a) shows the separation operation. At this time, the magnetic separator (86) is supplied with the raw material from the raw material tank (80) while maintaining the horizontal state, and the filtrate is filtered while being magnetized and separated. The raw material tank (90) is supplied.

  FIG. 6B shows a process of removing the magnetization / separation after a certain degree of progress, and after the magnetic separator (86) is tilted obliquely, the air is first blown from the blower (112) of FIG. The raw material remaining in the magnetic separator (86) or the filtered raw material liquid is returned to the raw material tank (80). The electromagnetic coil is operated as it is so that the magnetized material does not fall. Residue was poured out by blowing air, and it was devised not to increase the raw materials that have to be reprocessed.

  6 (c), after removing the residue, return the magnetic separator (86) to the horizontal again, demagnetize while rotating the rotating shafts (92) and (94) in FIG. 5, and remove the particles adhering to the screw thread. It is a work process to peel off from. During this work, send a minimum amount of water for cleaning.

  In FIG. 6D, the magnetic separator (86) is tilted again, blown, and the magnetized particles peeled off are sent to the magnetized substance tank (102).

  In the high gradient magnetic separation apparatus of the present invention, actually, the system depicted in FIG. 5 is provided with two systems, while one system is separated as shown in FIG. As shown in FIG. 6 (d) to FIG. 6 (d), they are alternately operated so as to wash the magnetized / separated material. By switching this operation in a very short time, the magnetized material adheres to the magnetic material so that the high-gradient magnetic field does not dull due to the adhered material. In other words, the device was devised so that as soon as it started to attach a little, it was washed, the adhering matter was dropped, and a new magnetization separation was started.

  As described above, in the present invention, as shown in Japanese Patent Publication No. 53-44260, the high gradient magnetic separation device has been reviewed and devised from all points of view so that a non-magnetic material can be magnetized without flowing a high current.

The characteristics of the device of the present invention that removes from weak magnetism to non-magnetic material by power of 15 kW to 100 kW are listed below. (1) Conventionally, an electromagnetic force application unit (magnetic separation shown in FIGS. 5 and 6) For example, the material flowed from the top to the bottom of the machine and passed through the magnetized / separated part of the ferromagnetic material produced in a mesh shape. It was necessary to magnetize and separate the particles by applying a magnetic force greater than the force that antagonizes the combined force of these two forces and adding these two forces together. For this reason, a strong magnetic force was required, but if this was made horizontal, it would be possible to produce even when the force in the direction of gravity need not be considered.
(2) Further, based on the horizontal type, the electromagnetic force application part can be divided into a plurality of sections and installed, and the electromagnetic force application part can be made longer. If a vertical type and multiple sections are provided, the backwashing is performed by flowing water from the bottom to the top, the height becomes high, high pressure washing is required, the amount of water used increases, and the washing water is treated. I was in trouble.
(3) The electromagnetic force applied to the plurality of sections can be changed by dividing the electromagnetic force application section into a plurality of sections. The electromagnetic force applied to the electromagnetic force application unit divided into multiple sections is gradually increased along the direction of flow of the raw material. At first, ferromagnetic iron or nickel is removed. If it is possible to magnetize / separate even non-magnetic ones, it is possible to prevent the high gradient portion from becoming dull due to magnetization and the separation force from declining.

In this apparatus, it is necessary to clean and remove the magnetized particles while increasing the magnetic gradient. Until now, electromagnetic force was applied to a ferromagnetic material produced in a mesh shape, and particles were magnetized and separated and removed.However, since the magnetic force remains after demagnetization, the particles can be washed. It was quite difficult to wash away. Therefore, in the present invention, following the above (1) to (3), the following devices were made.
(4) Place a cylindrical body supported by rotating bearings at both ends in the electromagnetic force application section, and insert many small screw nails into the cylinder body. A part with a high magnetic field gradient was made in the pointed part of the material, and the fluid was magnetized on the screw as the raw material flowed through the cylinder. Since this cylindrical body is operated not only when the raw material flows in but also during cleaning, after degaussing, the thread can collide with each other and can quickly wash away the particles that have been magnetized by the impact.
(5) By changing the electromagnetic force application part between the horizontal state and the inclined state according to the operation process, and by washing with a blowing process, it was possible to save the trouble of reprocessing by using excess water. .
(6) Two series of high gradient magnetic separators shown in FIG. 5 are provided, and “magnetization / separation” and “cleaning” are replaced with each other. The device can be used.

These are the basic block diagrams which show the low-temperature baking method of the ceramics using the waste ceramics by this invention. FIG. 2 is a block diagram showing a ceramic production system based on FIG. 1 according to the present invention; These are the tables of the confirmation of porcelainization according to the composition ratio of the test piece according to the present invention and the set temperature of the firing furnace. Is a basic block diagram of the present invention when a high gradient magnetic separation device according to the present invention is used. 1 is a basic block diagram of a high gradient magnetic separation device according to the present invention. FIG. These are explanatory drawings for demonstrating the operation | movement function of the high gradient magnetic separation apparatus shown in FIG. These are the X-ray diffraction analysis figures of the kimono for demonstrating this invention.

Claims (7)

  A first step of dry pulverizing waste ceramics to a particle size of # 350 mesh or less, a second step of wet pulverizing the dry pulverized product to a particle size of about several μ, and adding plasticity to the wet pulverized product A third step of adding an agent and a low melting point additive and kneading, a fourth step of molding the kneaded product, and a fifth step of firing the molded product at a low temperature of about 1150 ° C. or lower. A low-temperature firing method for ceramics.   In a ceramic firing method mainly composed of pulverized powder from discarded ceramics, a plastic additive based on natural clay and a low melting point additive made of glass, soda feldspar, etc. are added, and the addition of silica stone is newly eliminated. A method for low-temperature firing of ceramics, which enables low-temperature firing at about 1150 ° C. or less depending on the method.   The low-temperature firing method according to claim 2, wherein a composition ratio of the pulverized powder is approximately 50% or more.   3. The ceramic low temperature according to claim 1, wherein natural plastics are separated by a centrifugal separator, silica sand and the like are removed, and plastic parts are taken out with a high density as the plastic additive. Firing method.   2. The method for firing ceramics according to claim 1, wherein the wet pulverized product is subjected to a step of separating and removing impurities through a high gradient magnetic separator.   A ceramic baked by the low-temperature baking method according to any one of claims 1 to 5.   The clay for ceramics according to any one of claims 1 to 4, which can be fired at low temperature.

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