JP2002047075A - Ceramics porous body and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high quality low-cost ceramics porous body utilizing an amorphous slag generated in a ductile cast iron-making process. SOLUTION: The amorphous slag generated in the ductile cast iron-making process is broken and screened to a particle with size of 0.25-2.0 mm. A plastic clay is mixed with the particle sized slag, then formed, bloated and sintered at 900-1100 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention utilizes an immonoslag which has been almost discarded up to now, and provides a completely new and highly inventive ceramic material with an added value of 10 times or more. About. In other words, in the production process of a wide range of ductile iron products such as automobile engines and cast iron pipes for waterworks, it is necessary to add some additional materials to 30% of the products, imonoslag which is discharged in large quantities, and apply advanced new technologies. The present invention relates to a novel porous ceramic body which is lightweight, has high strength, has high weather resistance and is beautiful, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, the following techniques exist as a lightweight, rigid ceramic porous body having continuous through pores. In the first prior art, a method of manufacturing by filling a ceramic composition into pores of a urethane foam resin or the like and then burning the resin portion has been known for a long time, and has also been commercialized.

In the second prior art, porcelain cerven, glass balloon, coal ash clinker, municipal waste slag, etc. are sized to coarse particles as a sound absorbing material or water-permeable ceramic, and a forming binder or a sintered binder is formed. In addition, some of which have been fired after dry press molding and have pores in pores have been recently developed and have been established in the market.

[0004] A third prior art is a foam glass product which has long been known as a foam glass product in which pores are formed by a high-temperature decomposition volatile component incorporated in a composition in a firing process of a formed material. Most of the products are closed cells, and the material of the product is amorphous glass.

[0005]

However, the above prior arts have various serious drawbacks, such as high cost, relatively high specific gravity, and easy cracking. That is, in the first prior art, since the ceramic porous body using the urethane foam resin uses an inorganic material and an organic material as raw materials, the manufacturing process is complicated, and the organic material is expensive. As a whole, the production cost is extremely high, the unit price per t reaches 500 to 1,000,000 yen, and there is a major drawback that ordinary construction materials cannot be widely used at general sites.

In the second prior art, although it has been recently developed and is used and established to some extent in the general market, the clinker or the like as a raw material thereof is of a normal stone type. All have high specific gravities, and the specific gravity of the product as a whole is 1.5 or more and around 2, which is large for porous ceramics, which is inconvenient for use and more brittle. As a material, there is a major problem that the production is difficult and the construction cost eventually increases.

In the third prior art, the foam glass product is made of independent foams and therefore has no air permeability, and is made of amorphous glass. It has the greatest drawback that it is weak and easily cracked by heat and cracks.

The present invention solves the above-mentioned drawbacks and problems of the prior art. In particular, it is low-cost, lightweight, high-strength, has continuous pores, does not crack, has excellent weather resistance, and is beautiful. In order to develop materials, we have focused on slag discharged as waste during the production of ductile cast iron products, and have been studying the characteristic properties of these resources for many years. Patent No. 2899954 is used as a basis for the technical content of a basic patent for which permission has been registered as a "fossilized glass composition". That is,
In many respects, the present invention has been completed by studying various conditions related to the production of a low-cost porous ceramic body as an industrial product, which is outstanding in the prior art, and at low cost. Therefore,
It is an object of the present invention to provide an excellent and inexpensive product that is useful for improving the environment as a high-performance sound absorbing material, a fire-resistant heat insulating material, or a water-retentive building material, which has never existed before.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides the following novel structure and manufacturing method. That is, the ceramic porous body, which is a novel material, is a flat plate having continuous through pores.
It is a block-shaped or pipe-shaped product and is made of crystallized glass having high strength, heat resistance and weather resistance.
This means, that is, the first feature of the present invention is that an amorphous slag produced during the production of a ductile cast iron product is crushed and sieved and sized to a particle size range of 0.25 to 2.0 mm. The individual particles are shaped so as to be wrapped by a plastic clay, and the composition is used in a range of 900 to 1100.
By heating in a temperature range of ° C., the individual slag particles are foamed as individual pieces, mutually sintered, and are ceramic porous bodies having continuous through pores.

[0010] The first feature (claim 1) of the present invention will be further described. It specifically specifies the content of slag as a main raw material. That is to say, extensive research was conducted on unutilized resources in the range of chemical components shown in Japanese Patent No. 2899954, and experiments were conducted. As a result, any of the slags used in the production of ductile cast iron could be used. Since it had no effect unless it was a thing, it specified. Although the expansion ratio increases as the particle size becomes coarser, the reason why the expansion ratio is 0.25 mm or more is that fine particles smaller than 0.25 mm did not meet the purpose. Also,
The raw material that wraps the individual particles, such as binders used in general ceramics, such as sodium silicate and sodium aluminate, does not foam at all, and is sintered at around 900 ° C and suitable for the reaction system with slag. It is a plastic clay such as Kibushi clay, Frog eye clay and bentonite, and also serves as a molding binder at the time of molding.

A second feature of the present invention is that an amorphous slag produced during the production of a ductile iron product is crushed and sieved and adjusted to a particle size range of 0.25 to 2.0 mm. 50-80%, plastic clay 20-50
%, And the composition mixed and kneaded so that the water content becomes 12 to 25% in external proportions, if necessary, using a vacuum kneading machine to form a desired shape by rolling, drying, and drying. 1
This is a method for producing a ceramic porous body fired at a temperature in the range of 150 ° C.

The second feature (claim 2) of the present invention will be specifically described. This shows the range of the mixing ratio of the slag and clay. In order for the individual slag particles to be fully enveloped by the clay, the results of the experiment require a minimum of 20% clay,
Also, if it exceeds 50%, the expansion ratio is greatly reduced.
The mixing ratio of the clay was limited to 20 to 50%. Further, as in the case of general ceramic products, by extruding with a vacuum kneader, the latent pressure before explosive foaming of the particles is increased without dissipating the volatile gas components of the slag particles. The reason for setting the firing temperature in the range of 900 to 1150 ° C. is that foaming occurs at 900 ° C. to form a porous body, but the foam of individual particles is welded,
Although the number of independent pores was large, when the temperature exceeded 900 ° C., the particles after foaming were sufficiently welded, and the remaining gas components turned into continuous-penetrating pores. Even at a temperature of 1150 ° C. or higher, the molded body is not deformed, but there is no particular improvement in physical properties, but it is disadvantageous in terms of economy.

Next, a third feature of the present invention is that an amorphous slag produced during the production of a ductile cast iron product is crushed and sieved and adjusted to a particle size range of 0.25 to 2.0 mm. 50-80% by weight, plastic clay 20
The composition which was added, mixed and kneaded so as to have a water content of 12 to 25% was formed into a desired shape using a vacuum kneader, and then dried to a water content of 1% or less. After that, sufficient uniform heating is performed according to the thickness from room temperature to 700 ° C., and then in a temperature range of 700 to 1000 ° C., 20
Heat rapidly at a heating rate of ４０40 ° C./min to explode the individual particles explosively, and then 1000 to 1150 ° C.
This is a method for producing a porous ceramic body that is sintered at a temperature.

The third feature (claim 3) of the present invention will be described. This limits the heat sintering conditions. That is, the period during which crystallization starts from a temperature exceeding 700 ° C. and the liquid phase is generated by phase separation is an important temperature range of the foaming mechanism of the present invention. Until then, it is necessary to complete the dehydration of the clay crystal water, which is almost uniformly heated. If the temperature exceeds 700 ° C., the heating rate is increased to 10 ° C.
Heating slowly for about a minute to equalize the temperature of the surface and inside, but increase the rate of temperature rise from 850 ° C to 1000 ° C, measure the rapid decrease in viscosity, explosive foaming and particle welding of particles 20 to 40 ° C./min. Because it is necessary to perform the heating all at once. However, it is necessary to adjust the heating rate depending on the thickness of the object to be heated. 11 in the temperature range above 1000 ° C
Up to 50 ° C., the product strength can be increased by increasing the heating temperature.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) Embodiments will be described more specifically and in detail, including the operation of the present invention. As described in the basic patent, Patent No. 2899954, the present invention discloses that when a vitreous slag having a specific chemical composition is heated above 700 ° C., the SiO ₂ —Al ₂ O ₃ —C
The removal of crystals such as aO occurs, and at the same time, the low-viscosity liquid phase is separated. SO ₃ is an exploded volatile components are iron, present in the glass phase in a form bound to manganese, the decrease in the viscosity of the glass phase due to the rise in temperature in the vicinity of potential accumulated gas component 900 ° C., the individual It is built on a completely new theory that particles explode at once to form a foam.

(2) When the slag, which is the main raw material of the present invention, is heated as a single particle, each individual particle expands and expands in volume, but the surface is covered with a vitrified layer. And independent cells, and the expansion ratio is 2
When the particle size is 0.25 mm or less, the particles are welded to each other, but almost no foaming phenomenon is observed. In addition, when a clay layer was applied to the surface of the slag particles and fired, it was found that the expansion ratio was increased by about 20 to 30%, but the pores were mostly independent pores.

From the results of the above preliminary experiments, the mechanism of the reaction, foaming and sintering in the present invention was studied based on the following design. 1) The slag particles need to have a particle size of 0.25 or more, and the particles are wrapped in clay and formed individually, and the volatile gas component during firing and foaming is compressed and sealed in the clay layer to form a gas. A molded body that can prevent escape as much as possible. 2) slag phase separation takes in Al ₂ O ₃ crystals generated and composition as the main phase of _{CaO · Al 2 O 3 · 2SiO} 2 begins gradually crystallized exceeds 700 ° C. CaO-Si
A high-viscosity glass phase comprising O ₂ as a main component, MgO.K ₂ O.Na ₂ O, and a foaming source of iron sulfide and manganese sulfide is generated. Decomposition temperature of iron sulfide and manganese sulfide takes place between 700 to 900 ° C. in theory, the viscosity of the glass phase, when he does not have 10 ⁵ poise or less, said foamed release does not occur. In addition, the clay layer wrapping the particles starts sintering and becomes more wrapped around the particle surface,
The state before the explosion with high potential pressure. 3) When the temperature further rises, the viscosity of the glass phase decreases, and when the temperature reaches 10 ⁴ to 10 ³ poise, the latent gas component is explosively released at a stretch and the individual particles are fused together. By foaming, a porous ceramic body having continuous through pores is obtained.

(Example) The slag slag used in this example was generated during casting of an automobile engine, and its chemical components were 38% SiO ₂ , 13.0% Al ₂ O ₃ , and CaO.
43%, MgO ₂ %, K ₂ O + Na ₂ O 1.8%, MnS
1.81%, FeS 0.4%, CaO + MgO
/ SiO ₂ ratio is 1.18, Al ₂ O ₃ / SiO ₂ ratio is 0.3
I got 4. Particle size: The size of the pulverized product was set to 1 mm or less, and those sieved with a 0.25 mm sieve, that is, particles of 0.25 mm or more were used. Mixing ratio; (weight ratio) Slag clay (Frogme clay) Bentonite No1 60% 40% --- No2 70% 20% 10% No3 74% 18% 8% Molding; Then, water is added to the mixture in an amount of 12 to 15% (adjusted according to the amount of clay), and the mixture is kneaded. Then, the mixture is kneaded using a vacuum kneading machine to a degree of vacuum of -760 mmHg.
And extruded, width 30cm length 50cm thickness 1.0c
m plate-shaped dough was prepared. Drying: drying was performed until the water content reached 1%. Baking; using roller-hardened kiln;
The temperature was raised at a rate of 10 ° C./min from 700 to 850 ° C., and then rapidly increased from 850 ° C. to 1050 ° C. at a rate of 20 ° C./min. After holding, cooling was performed to obtain a fired product. Physical properties of the sintered body; slag weight as bulk density flexural strength porosity ^{No1 0.78 72kg / cm 2 61%} No2 0.66 38kg / cm 2 67% No3 0.55 27kg / cm 2 72.5% or more The porosity increased with the increase, and a good flat plate-shaped ceramic porous body whose volume was increased about three times was obtained from the dried green plate. The results of measuring the sound absorption coefficient by the vertical incidence method in order to use the fired body of No. 3 as a road sound absorbing material are as follows. Frequency Hz 400 500 630 800 1000 1250 Sound absorption% 0.65 0.89 0.95 0.80 0.78 0.64 Therefore, the material of the present invention was determined to be an extremely high-performance material as a sound absorbing plate.

[0019]

1) The present invention is a further application and development of the basic invention of the same inventor, Japanese Patent No. 2,899,954, which is an unused and low-cost resource for producing ductile cast iron products. By utilizing slag discharged in large quantities to a high degree, there is a tremendous effect that high value-added products can be produced. 2) As a specific effect, a lightweight and high-strength, weather-resistant and high-quality ceramic product having continuous through pores uniformly expanding in volume can be produced at low cost by crystallization and foaming action of sulfides of Mn and Fe. For example, a conventional metal composite material, which is a sound absorbing plate that is a necessity for the side wall of a highway, is expensive and has a short service life due to corrosion. On the other hand, if the product of the present invention is used, the cost is about half. As a result, the service life is several times longer, and as a result, an enormous effect that an economically advantageous product can be supplied to society about ten times can be obtained. 3) Furthermore, for example, the sound absorbing plate on the side wall of the highway used up to now is composed of various materials such as metal and organic material, so that the disposal cost is extremely high as a waste at the time of replacement. Since the material of the invention is inorganic, it can be recycled at low cost and does not cause pollution.

Claims (3)

[Claims] 1. An amorphous slag produced during the production of a ductile cast iron product is crushed and sieved to a size of 0.25 to 2.0 m.
m, and the individual particles are shaped so as to be wrapped by the plastic clay. By heating the composition in a temperature range of 900 to 1100 ° C., A porous ceramic body characterized by having continuous through-pores, wherein the slag particles are foamed individually and mutually sintered. 2. An amorphous slag produced during the production of a ductile cast iron product is crushed and sieved to a size of 0.25 to 2.0 m.
m adjusted to a particle size range of 50 to 80 by weight.
%, Plastic clay is 20 ~ 50%, moisture is 12 ~
The composition which was added, mixed and kneaded so as to be 25%,
A method for producing a porous ceramic body, comprising: forming a desired shape by rolling using a vacuum kneading machine as required, drying, and firing at a temperature in a range of 900 to 1150 ° C. 3. An amorphous slag produced during the production of a ductile cast iron product is crushed and sieved to obtain 0.25 to 2.0 m.
m adjusted to a particle size range of 50 to 80 by weight.
%, The plastic clay is 20 to 50%, and the moisture is 12 to 25%, and the mixed and kneaded composition is rolled as necessary using a vacuum kneader to form a desired shape.
Next, it is dried to a water content of 1% or less, and thereafter, at room temperature to 70%.
After sufficient uniform heating according to the thickness up to 0 ° C, 7
In the temperature range of 00 to 1000 ° C., rapid heating at a heating rate of 20 to 40 ° C./min, explosive foaming of individual particles, and thereafter sintering at a temperature of 1000 to 1150 ° C. A method for producing a porous ceramic body.