JPH02289474A - Granulated blastfurnace slag sintered body and production thereof - Google Patents

Abstract

PURPOSE:To obtain a sintered body which has sufficient strength and continuous porosity and exhibits the feather of slag particles by mixing fine slag powder and sodium silicate with granulated blastfurnace slag particles, pressurizing and molding this mixture and thereafter calcining the molded body. CONSTITUTION:The aimed sintered body is obtained by adding 2-10 pts.wt. fine slag powder of granulated blastfurnace slag and 5-20 pts.wt. unhydrated sodium silicate to 100 pts.wt. granulated blastfurnace slag particle and mixing them and thereafter pressurizing and molding this mixture, dehydrating and drying the molded body and calcinating it at 800-1200 deg.C. in this granulated blastfurnace slag sintered body, the granulated blastfurnace slag particles are connected by a connected layer made of both the heated product of granulated blastfurnace slag and sodium silicate and the continuous pores opening on the surface of the sintered body. Further in the production of the above-mentioned sintered body, the design properties of the sintered body are enhanced by applying glaze to the surface of the molded body after dehydrating and drying it and thereafter calcining it or coating noncombustible inorganic coating on the surface of the sintered body.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is one of the advanced uses of blast furnace slag, which is abundantly generated as a by-product of iron manufacturing, by making granulated particles of blast furnace slag into a sintered body. The present invention relates to a sintered body used as a fire-resistant finishing material for building structures, and a method for manufacturing the same.

[Conventional technology] Blast furnace slag is used for civil engineering and roads (ground and roadbed improvement).
In addition, although it has been used for a long time mainly for concrete aggregate and cement, its use as a building material is extremely rare.

On the other hand, ceramic materials have traditionally been widely used as building materials for civil engineering and construction, but in recent years, their excellent fire resistance, durability, and unique design have been reevaluated, It can be used not only as a material, but also for paving boards for roads, parks, campuses, etc., soundproof walls for motorways, railways, factories, etc., walls for subways, tunnels, etc., walls, floors, roofs, external structures of architectural structures, etc. As a finishing material, it is being used in a variety of ways across general building materials, and its usage is increasing.

Conventionally, despite the abundance of raw materials, slag sintered bodies that can be used as building materials have not been obtained, and the main reason for this is thought to be that sufficient sintering strength was not obtained.

[Problems to be Solved by the Invention] The present invention aims to solve the drawbacks of the above-mentioned conventional techniques regarding granulated blast furnace slag, and to provide a sintered body of granulated blast furnace slag that can obtain sufficient sintering strength and a method for producing the same. It is something to do.

[Means for Solving the Problems] In order to solve the above problems, the present inventors have discovered that granulated blast furnace slag grains have continuous pores that open on the surface of a sintered body and a heated product of granulated blast furnace slag and sodium silicate. The present invention provides a sintered body of granulated blast furnace slag, which is characterized in that it is bonded by a bonding layer consisting of a As a manufacturing method, 2 to 10 parts by weight of the fine slag powder and 5 to 20 parts by weight of sodium silicate as anhydrous salt are added to 100 parts by weight of granulated blast furnace slag grains, and then mixed, followed by pressure molding. Dehydration drying, 8
This provides a manufacturing method that involves firing at temperatures above 00°C and below 1200°C, which involves applying a glaze to the surface of the molded body after dehydration and drying and then firing it, or painting the surface of the sintered body with a nonflammable inorganic paint. As a result, the design of the sintered body can be improved.

[Effect 1] By using an appropriate binder and sintering the granulated blast furnace slag grains, the present inventor has created a continuous porous sintered body that has seven times the strength and takes advantage of the characteristics of the slag grains. We manufacture water-permeable plates, especially for road paving.

We attempted to provide a material suitable for use in sound-absorbing and sound-insulating boards.

In that case, the main characteristics desired for the shaped sintered body are as follows.

■ Nonflammability, fire resistance ■ Strength depending on the application ■ Water permeability, water resistance ■ Sound absorption To obtain a slag building material that satisfies these characteristics,
Including the use of binders suitable for slag grains, raw material composition,
It is necessary to research and develop manufacturing technologies that cover all aspects of compounding, molding, and firing.

Since continuous porous roots are effective as sound-absorbing plates and water-permeable plates, it is believed that by molding and sintering granulated slag grains, which are obtained in large quantities as a by-product of iron manufacturing, it is possible to use them as porous plates that are useful for the above-mentioned purposes and have a high degree of fire resistance. Thought.

It is considered that it is sufficient to partially bond the slag grains without significantly changing the shape of the slag grains to make a porous plate, and to perform high-temperature sintering to make the slag highly refractory.

Also, depending on the application, sintered plates are required to have high strength. For example, as a transparent horizontal board for sidewalks, 40 kg/
Bending fracture strength of cr' or higher is required. (J
I5A5304).

Therefore, in order to obtain a sintered body with high sound absorption, water permeability, nonflammability/fire resistance, and strength, it is necessary to carefully adjust the composition and particle size of sintered components including binders and other additives, molding conditions, and sintering conditions. Finding the right range is essential.

For example, the chemical composition (wt%) of granulated blast furnace slag is shown in Table 1.
It is an amorphous granular glass mainly composed of CaO・n5i02 system which shows
It has a particle size distribution over mm.

1. In order to make a fire-resistant sintered plate having continuous pores from the slag grains, an experiment was conducted in which the slag particles were press-formed and fired at a temperature of 800° C. or higher.

After various studies, it was found that the desired sintered plate could be obtained by using sodium silicate as a binder to facilitate molding and promote sintering. If a binder is not used, a press-formed product cannot be obtained, and if an organic binder is used, the moldability is good, but the binder decomposes or burns before sintering occurs during firing, resulting in insufficient sintering. Strength cannot be obtained.

As an inorganic binder, in addition to sodium silicate.

Phosphates, polyphosphates, borates, and silica sols, alumina sols, and other metal oxides were also considered.
None of these substances is effective alone, and even when any of the above-mentioned substances was added to a sodium silicate base, no significant improvement in effectiveness was observed due to the addition.

Sodium silicate is thought to wet the surface of slag grains well and react with the slag surface from a relatively low temperature to form strong intergranular bonds. The amount of sodium silicate added is sufficient as long as it sufficiently coats the surface of the slag grains, and should be 5 to 20 parts by weight in terms of anhydrous salt per 100 parts by weight of granulated blast furnace slag, and should be within this range taking into account the particle size of the slag, etc. used in An appropriate amount of water may be added to facilitate mixing and formation, but this is not necessary if water glass is used. If the amount of sodium silicate added is insufficient, the sintering strength will decrease, and if it is too much, the number of continuous pores will be reduced and the composition of the sintered body will be uneven, resulting in adverse effects on water permeability and sound absorption.

100 parts by weight of granulated slag whose particle size distribution is shown in FIG.
A mixture of 10 parts by weight of water glass as anhydrous salt,
300X300X40mm at a pressure of 50kg/cm"
After press-molding into a plate shape, it was dried at 110℃ and heated to 800℃.
By firing at a temperature of ℃ or higher and lower than 1200℃,
Bending fracture strength of g/c rn' or more, approximately 0.3
A porous sintered plate having a water permeation rate of cm/sec or more (vertical water permeation falling rate when the water level of the room is maintained on a 40 mm thick sintered plate) was obtained.

Based on this (granulated slag, sodium silicate) mixture,
The effects of raw material particle size, mixture composition, firing conditions, etc. on the strength, water permeability, and sound absorption properties of the sintered body were investigated, and the manufacturing conditions for the sintered body were determined.The results are shown below.

When granulated slag powder is further added and mixed with granulated slag and sodium silicate, the bending fracture strength of the sintered body is improved and its variation is reduced. Figure 1 shows the bending fracture strength (according to J I 5A5304) due to the addition of pulverized blast furnace slag powder (trade name: Liberment, Blaine value of fineness 4000).
showed a change in Sintering raw material (granulated slag (particle size 21 mm)
, particle size ≧ 2 mm) 100 parts by weight, 12 parts by weight of sodium silicate or sodium phosphate, fine slag powder (Blaine value 4000)
0-15 parts by weight 1, press molding pressure 50kg/c
This is the result of an experiment conducted under the following conditions: 1,100°C firing temperature x 2 hours (slow cooling in the furnace).

Sodium silicate exhibits extremely high strength compared to sodium phosphate. In addition, the strength development by other pine and da, such as borates, was also extremely low compared to sodium silicate, as was the case with sodium phosphate.

As the amount of fine slag powder added increases, the strength improves, and at an amount of 5 parts by weight, it is almost saturated (approximately 100 kg/c rn"
). From this result, although some differences were seen depending on the particle size distribution of the granulated slag particles, the amount of fine slag powder added was set at 2 to 10% by weight.

If it is less than 2 parts by weight, the effect of addition is insufficient, and if it exceeds 10 parts by weight, no further improvement in strength can be obtained and the porosity of the sintered body may be reduced.

The reason for the strength improvement effect of fine slag powder is that the fine powder reacts with the binder (sodium silicate), and the composition of the binder approaches that of blast furnace slag, which improves its compatibility with blast furnace slag, and the contact between the binder and the slag grains. Near the boundary, the concentration gradient of the components is relaxed due to component diffusion with the slag grains, local reactions, etc., and the clear boundary fades to form an integrated, strong bonding layer. jT19 observation revealed needle-shaped crystals that reinforced the bonding layer, which is thought to be due to strengthening the bonding force between the granulated slag particles.

Fine slag powder has a fineness (Brain+a>too).

Those with a culm degree of ~5000 are preferably used.

On the other hand, as is clear from FIG. 4, almost no effect on water permeability due to the addition of fine slag powder was observed.

Figure 2 shows an example of the effect of the amount of binder added on the bending fracture strength of a sintered body.
m) 100 parts by weight, 5 parts by weight of fine slag powder, 0 parts by weight of binder
~40 parts by weight I, press molding pressure 50 kg/c
This is the result of an experiment conducted under the conditions of rn' and firing temperature of 1100° C. for 2 hours (slow cooling in the furnace).

Sodium silicate has a much greater effect of improving bending fracture strength than sodium borate, but if the amount added is less than 5 parts by weight, the effect is insufficient, and if it exceeds 20 parts by weight, variations in strength will increase.

Next, Figure 3 is an example showing the influence of firing temperature on the bending fracture strength of sintered bodies.
m) 100 parts by weight, 12 parts by weight of sodium silicate, 6 parts by weight of fine slag powder (Blaine value 4000), molding pressure 50 k
These are the results obtained under the conditions of g/c, rn'. As a result, the higher the firing temperature, the higher the strength, and the highest strength is obtained from approximately 1000°C to less than 1200°C, and at 1200°C, the crystallization of the glass progresses, causing volumetric expansion, and the shape changes due to softening. It was found that the strength decreased rapidly. Therefore, the firing temperature is 800℃
The temperature should be at least 1200°C.

At temperatures below 1000°C, the strength tends to increase as the firing time increases, but for reasons of energy and time saving,
The most desirable firing temperature is 00°C to 1170°C.

FIG. 4 illustrates the relationship between the water permeation rate of the sintered body and the particle size of the slag used. The slag particle size is granulated slag with the particle size distribution shown in Figure 8 (particle size ≦5 mm);
m); 3 on a screen (particle size ≧ 2 mm) classified with a 2 mm sieve
I researched the seeds. The conditions for producing the sintered body at this time were: sintering raw materials (100 parts by weight of granulated slag grains, 12 parts by weight of sodium silicate, 6 parts by weight of fine granulated slag powder (Blaine value 4000)), molding pressure of 50 kg/cd, Firing 1100℃×
2 hours (slow cooling in the furnace).

Even when fine powder is blended, the water permeability of the sintered granulated slag remains high without being impaired, and naturally, the larger the slag particle size, the higher the water permeation rate. Although it is slightly affected by the molding pressure and raw material mixing ratio, unclassified granulated slag (particle size ≦5
The water permeability rate is approximately 0.3 cm
/sec, about 0.9cm/sec for particle size ≧Lmm
c, it was about 2 cm/sec when the particle size was ≧2 mm. The apparent specific gravity also decreased as the slag particle size and water permeation rate increased, indicating an increase in the porosity of the sintered body.

From this result, the water permeation rate of the sintered body can be designed in advance by adjusting the particle size structure of the slag.

The sound absorption properties of the slag sintered body according to the present invention are shown in FIG. 5 with an example of measurement of normal incidence sound absorption coefficient.

For a 40 mm thick sintered plate manufactured under the same conditions as the sintered body used for the water permeation rate measurement described above, the back air layer thickness was Omm.
This is the measurement result of normal incidence sound absorption coefficient when

Significant sound absorption properties are observed compared to Cfl concrete blocks. It is well known that the sound absorption range and sound absorption coefficient vary greatly depending on the thickness of the material to be measured and the thickness of the back air layer. It is clear that the body has an inherently high sound absorption property. When the granulated slag particle size is large, the sound absorption coefficient decreases at low frequencies (below 500Hz),
A tendency to increase at 1000 Hz is also seen. Therefore, the sintered body according to the present invention can be made more effective as a sound-absorbing material for sound-absorbing and sound-insulating structures that meet the purpose by considering the slag particle size, the thickness of the sintered body, the thickness of the back air layer, etc. can be used.

The reverberation room sound absorption coefficients of the sintered body of the present invention and the commercially available sound absorbing plates of Company A and Company B are shown in FIG. 6, and the bending fracture strength is shown in Table 2.

Compared to the sound absorbing plates of companies A and B, the sintered body according to the present invention has
It shows the same level of sound absorption performance while using significantly higher bending fracture strength.

The application of glaze to the surface of the molded body after dehydration and drying and the application of nonflammable inorganic paint to the surface of the sintered body are carried out using the spray method,
This can be done by a roll method, etc., and the pores on the surface are sealed (by doing so, the design can be improved without impairing the water permeability and sound absorption properties of the sintered body).

[Example 1 Example 1 100 parts by weight of granulated blast furnace slag whose chemical components (wt%) are shown in Table 3 and particle size distribution shown in Figure 8, and pulverized blast furnace slag powder (Blaine value: 400,016 parts by weight) 12 parts by weight of water glass No. 2 (anhydrous salt Na20 ・2.5S i
6 parts by weight as 02), anhydrous silicate soda No. 3 (Na2
6 parts by weight of 0.3.3SiO2) were mixed and molded using a compression molding machine at a molding pressure of 50 kg/crn' to form a 300×300
It was molded into a root shape of 40mm x 40mm.

Table 3 After thoroughly drying this molded body at 110°C,
It was fired at 211 °C and slowly cooled (furnace cooling) to 100 °C to obtain a sintered body.

The apparent specific gravity of this sintered body is 1.7 (porosity approximately 35%)1
Bending fracture strength is 98kg/cm'', water permeation rate is 0.35
cm/sec, and the direct incidence sound absorption coefficient showed higher sound absorption than concrete blocks, as shown by the x-marked curve in Figure 5.

Example 2 Granulated blast furnace slag with a particle size of 1 mm or more was used, and the rest was mixed with the same composition as in Example 1, molded and dried under the same conditions, and a commercially available glaze (manufactured by Nippon Ferro Co., Ltd., Approximately 3 ceramic NF)
00g/rn' spray coating, firing at 1150°C for 2 hours, and slow cooling (furnace cooling) to 5100°C to obtain a glazed sintered sintered plate. The apparent specific gravity of the sintered plate is 1.6 (porosity approximately 40%)
1 bending breaking strength is 95 kg/c rn', water permeation rate is 0.35 cm/sec, and the normal incidence sound absorption coefficient is 5th.
It exhibited high sound absorption properties, almost the same as the curve marked Δ in the figure.

The glazed layer covered the surface particles while leaving the pores of the sintered plate, giving it a highly designed appearance unique to pongee medicine.

Example 3 A sintered plate was produced using granulated blast furnace slag with a particle size of 2 mm or more, and under the same conditions as in Example 1. 110g
/ Painted with a roller, 200℃ x 20 m i
Baked with n.

The apparent specific gravity of the obtained decorative sintered board was 1.4 (porosity approximately 47
%) 1 bending breaking strength was 94 kg/cm'', and the water permeation rate was approximately 2 cm/sec. The sound absorption coefficient was as high as that of the reverberant house method.

The inorganic coating film was well-adhered to the surface layer slag particles without filling the pores, and a decorative surface with good fire resistance and stain resistance was obtained.

In addition, when coating with the inorganic paint, a coating film can be formed without sealing the pores of the sintered body by appropriately adjusting the viscosity, coating thickness, etc. of the inorganic paint.

[Effect of the invention 1 According to the present invention, '! A perforated sintered body obtained using granulated blast furnace slag, which is a secondary iron product of iron, has at least 40
It has a bending crushing strength of more than kg/c, high water permeability and sound absorption, and its ftQ is determined by the particle size distribution of the granulated blast furnace slag, the amount of pulverized slag added, and the addition of sodium silicate. The amount and firing temperature can be adjusted by selecting one size, and by glazing or baking with inorganic paint, ml.1 fire bamboo material with a high degree of freedom in design without impairing the characteristics of the material can be produced. (1) It can be used in a wide range of civil engineering and construction structures, especially as surface materials and finishing materials.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between the amount of granulated blast furnace slag powder added and the bending fracture strength of the sintered body, Figure 2 is a diagram showing the relationship between the amount of binder added and the bending fracture strength of the sintered body, Figure 3 shows the relationship between the firing temperature and the bending fracture strength of the sintered body, Figure 4 shows the relationship between the particle size of granulated blast furnace slag and the water permeation rate of the sintered body, and Figure 5 shows the relationship between the FIG. 6 is a diagram showing the relationship between the frequency of sound and the superimposed incident sound absorption coefficient of the sintered body, and FIG. , Figure 7 is a diagram showing the relationship between the sound frequency and the reverberation room method sound absorption coefficient of the sintered body, and Figure 8 is a diagram showing the particle size distribution of granulated blast furnace slag.
It is a figure which shows an example. Representative of Kawatetsu Techno Research Co., Ltd. Patent attorney Yoshi Kosugi ○ Silicic acid sorter △ Panmic acid sodebin ink '5 7 IOv (parts by weight) Figure 2 11 Amount of granulated blast furnace slag fine powder added [Weight Figure 1 Formation temperature ("C) Figure 3 3≦ ≧1 ≧2 Particle size (mm) Approximately 1.7 Approximately 1.5 Approximately 1.4 Grain weight ζ → = Invention b-me: Company A x-X: Bit, 5001α℃ Door skin curve length Hz 2α (4α℃ Fig. 6) Frequency penetration (Hz) Fig. 7

Claims (1)

[Claims] 1. Granulated blast furnace slag grains are bonded by a bonding layer consisting of a heating product of granulated blast furnace slag and sodium silicate and continuous pores opening on the surface of the sintered body. sintered granulated blast furnace slag. 2. The granulated blast furnace slag sintered body according to claim 1, which has a glazed layer on the surface. 3. The granulated blast furnace slag sintered body according to claim 1, which has a nonflammable inorganic coating film on its surface. 4. To 100 parts by weight of granulated blast furnace slag, 2 to 10 parts by weight of the slag fine powder and 5 to 20 parts by weight of sodium silicate as anhydrous salt are added and mixed, followed by pressure molding, dehydration drying,
A method for producing a sintered granulated blast furnace slag, characterized by performing firing at a temperature of 800°C or higher and lower than 1200°C. 5. The method for producing a sintered granulated blast furnace slag according to claim 4, wherein the surface of the molded body after dehydration and drying is glazed and then fired. 6. The method for producing a sintered granulated blast furnace slag according to claim 4, wherein the surface of the sintered body is coated with a nonflammable inorganic paint.