JP3446409B2 - Method for producing water-permeable ceramic block - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes effective use of a large amount of steel slag, and is used for road structures, such as roadways,
The present invention relates to a method of manufacturing a water-permeable ceramic block suitable for paving a sidewalk, a park or other plaza, a parking lot, and the exterior of various structures (buildings, etc.).

[0002]

2. Description of the Related Art In recent years, it has been important to reduce rainwater flowing into sewers and urban rivers by returning rainwater to the ground to reduce the burden on sewage treatment plants and prevent river flooding. It has become a challenge. It is also important to prevent the depletion of groundwater by returning rainwater to the ground, prevent land subsidence, and promote planting in urban areas. Furthermore, there is little bounce when it rains,
There is also a demand for sidewalks with excellent walking sensation that prevent puddles from forming. The water permeable block is drawing attention as a material suitable for satisfying such requirements.

The applicant of the present application has already proposed Japanese Patent Application No. 7-38197 as such a water-permeable block. In this invention, the maximum size of aggregate is 4.75 m
Inorganic aggregate having an average particle size of 1.5 to 2.5 mm or less is used as a base layer material, and as the inorganic aggregate, crushed materials such as steel slag, natural stone, and ceramics are used. Is proposed.

However, even if the maximum size and the average particle diameter are passed through the crusher within the specified range and the particle size distribution is wide, especially when the particle size is wide, the molding It was found that sufficient properties cannot be obtained in terms of filling properties, strength after firing, and water permeability.

If the amount of the sintering binder is increased or the firing temperature is increased for the purpose of improving the strength,
At the same time as the porosity decreases and the water permeability function further decreases,
The water retention is also reduced.

In particular, when using a crushed material of steel slag,
Compared with the case of crushing ceramics, the iron and steel slag has a property that the particle size distribution easily spreads to the fine particle side, and the above problems are remarkable. However, by using steel slag as an aggregate, there is an advantage that a large amount of cheap and stable quality raw materials can be used, and because of the porosity of steel slag,
The water-permeable block in the present invention is not only water-permeable,
It has a feature that it can exhibit excellent water retention. That is, in addition to the water permeability function that can be returned to the ground, the water retention function has the effect of preventing a marked rise in road surface temperature, unlike concrete or asphalt pavement. This is because the water stored in the block gradually evaporates after rain or water sprinkling, and promotes evaporation of water from the ground even when water sprinkling does not occur.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of conventional water-permeable ceramic blocks, makes it possible to effectively utilize a large amount of steel slag, and is excellent in water permeability and strength. In addition, it is an object of the present invention to provide a manufacturing method capable of stably producing a water-permeable ceramic block which is excellent in water retention and is particularly suitable for paving sidewalks, parks and other plazas.

[0008]

The present invention adopts the following means in order to solve the above problems. That is, the method for producing a water-permeable ceramic block of the present invention,
Maximum particle size observed including iron and steel slag 75% by weight or more or less 9.5 mm, and particles in the range of 9.5~4.75mm
Less than 20% by weight, particles in the range of 4.75 to 1.18 mm
50% by weight or more of particles, particles in the range of 1.18-0 mm
It is characterized in that a mixture containing an aggregate having a particle size distribution of less than 40% by weight and a sintered binder is molded and then fired.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, the filling property at the time of molding, the strength after firing, which is caused when the aggregate constituting the block has a wide particle size distribution and a wide particle size distribution on the fine particle side, After a thorough study on problems such as water permeability function, further decrease in porosity due to increased sintering binder, further decrease in water permeability function and decrease in water retention, etc., steel slag has a specific size, and further a specific particle size distribution. It has been clarified that the above problems can be solved all at once by positively adopting the above and mixing the sintering binder.

According to the present invention, for the first time made of steel slag,
Moreover, stable production of a ceramic block excellent in water permeability, strength and water retention could be realized.

The water-permeable ceramic block of the present invention is commercialized through the following adjustment of the base layer material, adjustment of the surface layer material, molding step and firing step. Hereinafter, detailed manufacturing methods in each step will be described in detail.

That is, it is important that the aggregate used in the present invention is steel slag for the reason described below .
The smelting iron and steel slag is obtained by separating a molten slag that is produced in a large amount during the smelting of steel, recovering it, and then cooling it, and there are blast furnace slag, converter slag, electric furnace slag, and the like. Such steel slag is an aggregate whose quality is stable compared to natural raw materials,
It is also optimal as a raw material for civil engineering and construction materials that are consumed in large quantities. The aggregate used in the present invention is made of such steel slag.
It is an aggregate containing 5% by weight or more. As for the size of the iron and steel slag, the one having a grain size of maximum size 9.5 mm or less is used. More preferably, particles in the range of 9.5 to 4.75 mm are less than 20% by weight, particles in the range of 4.75 to 1.18 mm are 50% by weight or more, and particles in the range of 1.18 to 0 mm are 40% by weight. It is important to use those with a particle size distribution that is less than%.

25% by weight of raw materials other than iron and steel slag
If it is contained in excess of the above, the porosity, high fire resistance and quality stability of steel slag are lost, the molten part of the aggregate increases during firing, the shrinkage also increases, the product's dimensional accuracy, porosity, water permeability Function deteriorates. When the aggregate having a particle size of more than 9.5 mm is contained, the strength and the surface smoothness of the product are impaired. 9.5
Even if the content of particles in the range of up to 4.75 mm is 20% by weight or more, the strength and the surface smoothness of the product are similarly impaired. 1.18-0
When the particle size distribution is such that the particles in the range of mm exceed 40% by weight, the filling property during molding is impaired and the strength after firing is reduced. In addition, the size of the voids increases in some parts, and the water permeability decreases.

Among the particle size distributions of such steel slag, 1.
18 to 0.425 mm range is less than 30% by weight, 0.4
The range of 25 to 0 mm is more preferably less than 10% by weight, and the above-mentioned product characteristics, that is, strength, product smoothness, and water permeability are further improved. In the present invention, the maximum size of the crushed pieces is expressed as the nominal size of the smallest sieve among the sieves that sieves 500 g of the aggregate through a sieve specified by JIS Z8801 and 100 to 95% by weight of the aggregate passes. . The particle size distribution is also JIS Z8.
Sift 2 kg of aggregate with the sieve specified in 801.
Expressed as the weight ratio.

[0015] Steel slag used in the present invention is preferably one that Ca O content is in the range 35 to 55 percent by weight, further Ca O is between _{Al 2 O 3, Si O 2} , Mg O And preferably has a melilite type crystal structure. The CaO content can be quantified by chemical gravimetric analysis, atomic absorption method, fluorescent X-ray analysis method, or the like. Ca O
If the content is out of the range of 35 to 55%, rapid shrinkage occurs during firing, dimensional accuracy is poor, and variations in strength and water permeability between products become large. The crystal structure of melilite system, and gehlenite of _{2Ca O · Al 2 O 3 ·} Si O 2, which contains a lot of solid solution of Akerumanaito of _{2Ca O · MgO · 2Si O 2} , the X-ray diffraction method gehlenite and Akerumanaito of The crystal structure can be confirmed. In steel slag, depending on the cooling method and degree from the molten state,
Slags with different vitrification rates can be obtained. When quenched, slag with a high vitrification rate is produced. Such slag generates many cracks and bubbles due to thermal shock of quenching, and it is difficult to obtain an aggregate having a desired strength and particle size. Further, the glassy material is extremely likely to react with the sintering binder and other additives during firing, has a large shrinkage and deteriorates the dimensional accuracy, has the tendency to trap the pores penetrating it, and reduce the water permeability function, It is preferable to use crystalline slag having a low vitrification rate. What is crystalline slag?
In view of the Ca O _{content, Al 2 O 3, Si O} 2, Mg O
Those having a melilite-type crystal structure between and are preferably used, and a slag whose diffraction pattern can be confirmed by an X-ray diffraction method is preferably used.

On the other hand, as the sintering binder, feldspar, clay, natural stone or glass powder having a lower melting point than the aggregate can be used. The coefficient of thermal expansion of the binder is preferably equal to or higher than that of the aggregate in order to reduce the strain generated in the aggregate and the binder during firing. The binder melts during firing to bond the aggregates together, but the maximum particle size of the binder is preferably 0.425 m
Those having a size of m or less have the advantages that the aggregates are uniformly bonded to each other and that it takes less time to melt during firing, and energy costs do not increase. Also, the amount of binder is determined in consideration of the strength and water permeability of the block, but usually,
About 3 to 20 parts by weight is added to 100 parts by weight of the aggregate.

As the molding paste, an organic paste such as carboxymethyl cellulose (CMC), methyl cellulose or starch, or an inorganic paste such as water glass or cement can be used. Usually, the powder form is
Water it and use it in the form of an aqueous solution or paste. However, a method of mixing with dry powder and adding water to the mixture later may be adopted. The amount of the sizing agent is determined in consideration of the shape-retaining property at the time of subsequent molding and the handling property of the molded product at the time of firing, but usually about 5 to 20 parts by weight is added to 100 parts by weight of the aggregate. .

When mixing the aggregate with the sizing agent and the sintered binder, it is advisable to first add the sizing agent in a liquid state to the aggregate while gradually adding it to the aggregate, for example, in a shower. Next, it is advisable to add the sintering binder little by little to the mixture of the aggregate and the sizing agent and mix them. Here, the method in which the aggregate and the sizing agent are mixed in advance and the sintering binder is further added to and mixed with the mixture is most preferable. According to such a method, the liquid sizing agent is evenly spread over the surface of the aggregate. However, if these three components are mixed at the same time, the sizing agent and the fine sintered binder tend to agglomerate, and the agglomerated sizing agent adheres to the mold during molding, or the sizing agent and the sintering binder agglomerate. , Tends to reduce the original binding action. For the same purpose, fine particles contained in the aggregate, for example, particles having a size of 0.425 mm or less are sieved in advance and, like the sintering binder, after mixing the aggregate with a particle size exceeding 0.425 mm and the sizing agent, It is also preferable to add.

It is also possible to first mix the powder-form sizing agent with dry powder and then add water to the mixture, but this method
When the sizing agent is in a liquid state, it is very effective in the case where the viscosity is high, the dispersibility is poor, and aggregation is likely to occur.

Next, in the ceramic block of the present invention, it is possible to form the block only with such a base material, but it is preferable to form a surface layer of another specification on the above base material in terms of strength and smoothness. Is preferred. The surface layer material to be laminated on the surface layer portion of the base material block is prepared in the same manner as the base material.

The surface layer material has a maximum dimension of 5.0 mm.
Aggregate containing 50% or more of porcelain with a particle size distribution of less than 10% by weight in the range of 0.425 to 0 mm, or a maximum dimension of 5.0 mm or less, 0.42
An aggregate containing 50% by weight or more of steel slag having a particle size distribution of less than 10% by weight in a range of 5 to 0 mm is used. Of course, the above aggregates may be mixed and used. As the aggregate containing porcelain, waste materials such as porcelain tiles and power insulators can be used.

When the maximum size of the aggregate exceeds 5 mm, the slip resistance value of the surface layer when wet is small, and slipping easily occurs when wet such as during rainfall. Slip resistance is ASTM
Calculated according to E303. 0.4 in such aggregate
If the content of particles in the range of 25 to 0 mm exceeds 10% by weight, the filling property at the time of molding is poor, the shrinkage behavior is different between the base layer and the surface layer during firing, which causes distortion between layers and cracks in the surface layer. In addition, the size of the voids also tends to decrease as the small portions increase and the water permeability decreases.

Coloring of the surface layer can be achieved by adding a pigment when preparing the surface layer material. As such a pigment, iron oxide-based, titanium oxide-based, cobalt oxide-based, or other powder can be used, and is usually added to and mixed with the aggregate. Although the amount of the pigment depends on the degree of color development, 0.2 to 10 parts by weight is added to 100 parts by weight of the aggregate.

Further, when the surface layer material is prepared, it is possible to improve the designability by adding a spot material having a size equal to or smaller than that of the aggregate to make the surface design look like natural stone or form various patterns. it can. As the spotted material, artificial inorganic particles that have already been colored, particles that develop a dark color after firing such as pumice, manganese, iron and garnet are preferably used, and the addition amount depends on the design of the formation pattern. However, about 2 to 10 parts by weight is added to 100 parts by weight of the aggregate.

The surface layer thus obtained has a base material thickness of 20 to 80 mm and a thickness of 3 to 10 m in the molding step.
A surface layer having a thickness of m is preferable in terms of strength and smoothness.

Next, for the molding of the ceramic block, a method is used in which a mold is used and filling is performed so as to obtain a desired thickness after firing while considering the filling thickness. That is,
Although only the base material can be used as a product, in the case of forming a two-layer structure with the surface layer, first, the base layer material is put into a mold, and the primary molding is performed using a vibration press, and then the surface layer material is put on the mold, and then the material is put again. The method of pressurizing and molding is adopted.

The thus-formed product is then fired in a firing process to obtain a water-permeable block. The molded body is dried prior to firing, or when water glass is used as a sizing agent, carbon dioxide is allowed to act to primarily cure the water glass, or when cement is used, it is cured. It accelerates the hydration reaction and cures it, making it easy to handle.

A tunnel kiln, a roller hearth kiln, or the like can be used for firing. The firing conditions are determined in consideration of the fire resistance of the aggregate, the melting behavior of the sintered binder, etc., but the firing is preferably performed in the range of 800 to 1250 ° C.
The firing time depends on the types of the base layer material and the surface layer material, the size of the molded body, and the like, and therefore cannot be generally stated, but it is 2 to 72.
It's about time.

[0029]

The present invention will be described in detail below with reference to examples. Example 1 The blast furnace slow-cooled slag had a maximum particle size of 4.75 mm, 79% by weight of particles in the range of 4.75 to 1.18 mm, and 18% by weight in the range of 1.18 to 0.425 mm.
Aggregate was obtained by crushing and classifying so as to have a particle size distribution in the range of 0.425 to 0 mm being 3% by weight. As a result of fluorescent X-ray analysis, this blast furnace slag had a Ca 2 O 3 content of 42% by weight, and had an interplanar spacing of 2.85 angstroms by an X-ray diffraction method.
There is a strong diffraction peak at beam, the diffraction angle 2 [Theta] =. 10 to
From the 45 ° diffraction pattern, it was confirmed that the structure had a high crystallization rate of gehlenite or akermanite.

On this, water glass No. 3 was used as a sizing agent for the aggregate 1.
10 parts by weight to 100 parts by weight are added and mixed, and powder of waste plate glass (maximum size 0.3 mm) is used as a binder in the obtained mixture so that the amount is 10 parts by weight with respect to 100 parts by weight of aggregate. Was added and mixed to obtain a base layer material.

On the other hand, a crushed piece of porcelain tile waste material (maximum size: 1.7 mm, 6% by weight in the range of 0.425 to 0 mm is 6% by weight) is used as an aggregate, and iron oxide pigment is added to 100 parts by weight of the aggregate. 2 parts by weight, and water glass No. 3 is added as a sizing agent to 8 parts by weight with respect to 100 parts by weight of aggregate, and the resulting mixture is mixed with plate glass as a binder. Waste powder (maximum size 0.3m
m) was added and mixed in an amount of 8 parts by weight with respect to 100 parts by weight of the aggregate to obtain a surface layer material.

Next, the base layer material was put into a mold so that the thickness was 55 mm, and was primary molded at a pressure of 1 kgf / cm ² using a vibration press, and then the surface layer material was adjusted to have a thickness of 15 mm. Then, it was molded by pressurizing again with a pressure of 1 kgf / cm ² .

Next, carbon dioxide gas is caused to act on the molded body to primarily cure water glass No. 3, which is a sizing agent, and then it is fired at 1180 ° C. for 48 hours using a tunnel kiln to obtain a size of 10
A block having a thickness of 0 × 200 mm, a surface layer of 12 mm, a base layer of 48 mm, and an overall thickness of 60 mm was obtained.

The characteristics of the block thus obtained were evaluated, and the results were as follows.

For the porosity, the surface layer was cut and removed from the block, and a test piece of about 5 × 5 × 5 cm square was cut out to give 1
After drying at 05 ° C for 24 hours, it was cooled to room temperature and weighed w
The bulk density ρ 1 = w / V is obtained from (g) and the volume V (cm ³ ), and the apparent density ρ 2 obtained by the Archimedes method of the similarly treated test piece is obtained by the following formula.

Porosity (%) = (1−ρ1 / ρ2) × 100 Further, bending strength is JIS A1106, compressive strength is JIS R2206, and water permeability is JIS A12.
18 is calculated according to each. Regarding the water retention amount, the water retention amount per block was determined by immersing the dried block in water for 24 hours and then gently taking out the weight of the block so that water did not flow out.

The numerical values are average values for 10 blocks.

Porosity: 32% Water permeability: 1.5 × 10 ^-1 cm / sec Water retention capacity: 360 g / piece Mohs hardness of surface layer: 6 Sliding resistance when wet: 52 Bending strength: 58 kgf / cm ² , compressive strength: 205kgf / cm
²

[0039]

EFFECTS OF THE INVENTION According to the present invention, by using a large amount of steel slag that is produced, it is possible to suppress an increase in cost, and since the quality of the slag does not fluctuate, it is possible to obtain a stable high yield and strength. It is possible to provide a water-permeable block that is excellent in water permeability, dimensional accuracy, and water retention, has less surface abrasion, has good slip resistance when wet, is less susceptible to stains, and is easily washed and recovered.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C04B 38/00-38/10

Claims (11)

(57) [Claims] 1. A maximum particle size observed including iron and steel slag 75% by weight or more or less 9.5 mm, and a particle size from 9.5 to 4.7
Less than 20% by weight of particles in the range of 5 mm, particle size 4.75
50% by weight or more of particles in the range of 1.18 mm
Less than 40% by weight of particles in the range 1.18-0 mm
A method for producing a water-permeable ceramic block, which comprises molding a mixture containing an aggregate having a particle size distribution and a sintered binder, and then firing the mixture. 2. The method for producing a water-permeable ceramic block according to claim 1, wherein the mixture contains a molding paste. 3. The method for producing a water-permeable ceramic block according to claim 2 , wherein the molding paste is at least one selected from carboxymethyl cellulose (CMC), methyl cellulose, starch, water glass and cement. 4. The method for producing a water-permeable ceramic block according to claim 1, wherein the firing is performed in the range of 800 to 1,250 ° C. 5. The iron and steel slag has a grain size of 1.18 to 0.4.
Less than 30% by weight of particles in the 25 mm range, particle size 0.4
Method for producing a water-permeable ceramic block according to any one of claims 1 to 4 particles ranging 25~0mm are those having a particle size distribution is less than 10 wt%. 6. The steel slag has a CaO content of 35-5.
5 wt%, and method for producing a water-permeable ceramic block according to any one of claims 1 to 5 and has a crystal structure of the melilite system. 7. A molding the mixture so that the thickness of 20 to 80 mm, on which, permeability ceramic block according to any one of claims 1 to 6, firing was laminated aggregate comprising a surface layer Manufacturing method. 8. The surface layer has a maximum particle size of 5.0 mm or less, and 50% by weight of porcelain and / or steel slag having a particle size distribution in which the range of 0.425 to 0 mm is less than 10% by weight. The method for producing a water-permeable ceramic block according to claim 7 , wherein the method is made of an aggregate containing at least 100% by weight. 9. The thickness of the surface layer portion is 3 to 10 mm.
The method for producing a water-permeable ceramic block according to claim 7 or 8 . 10. A sintered binder, feldspar, clay, at least one water permeable manufacturing method of the ceramic block according to any one of claims 1 to 9 selected from natural stone and glass powder. 11. A molding method using a vibration press.
11. The method for producing a water-permeable ceramic block according to any one of 10 .