JPS6245187B2 - - Google Patents

Description

[Detailed description of the invention]

Conventionally, the artificial ultra-light aggregates produced in Japan include expanded perlite, which is made by crushing and firing obsidian, nacre, and pine rock, and expanded vermiculite, which is manufactured by a similar method. Urite).
Note that colored aggregates are not commercially available. Moreover, the expanded pearlite and expanded vermiculite not only absorb excessive amounts of water, but also have weak aggregates themselves, which weaken the strength of mortar and concrete, resulting in loss of kneading. Therefore, in an attempt to improve the problems of the conventional method, the present inventor has conducted a wide range of experimental research, and as a result, the present inventor has added an appropriate amount of water glass to a mixture of waste glass, clay, volcanic ash, and limestone powder. As a result, it was found that a product with almost the same specific gravity and excellent strength as artificial ultra-light aggregate made by conventional methods can be obtained, and can be fired at a relatively low temperature. This is the first feature of the present invention; concrete using this aggregate has high strength;
The second feature is that it is lightweight, has low thermal conductivity, and has a good sound insulation effect. The third feature is that by adding a metal oxide pigment as a raw material to the above-mentioned blended granules and firing them, a beautiful colored aggregate can be obtained both on the surface and inside. The present invention proposes a manufacturing method that can utilize currently idle cement manufacturing equipment that is old and has low productivity, that is, a manufacturing method that can effectively utilize the granulator (pelletizer) and rotary kiln used in cement manufacturing. And this is the fourth feature. That is, the artificial ultra-light aggregate according to the present invention is made by mixing glass powder with clay powder such as slate, shale, silt, mudstone, and volcanic ash, and then adding an appropriate amount of limestone powder and water glass and granulating it. Furthermore, if necessary, an appropriate amount of metal oxide pigment is added to the raw material of the granules, and these granules are fired, thereby providing an artificial ultra-light aggregate at a low cost and reducing resource depletion. The aim is to help alleviate these problems and help solve these problems. In the present invention, the limitation of the composition range of the raw materials and the firing temperature range as described above will be explained in detail based on experimental results as follows. [Experimental Method] This experiment was conducted on a system in which glass-clay (clay raw material)-volcanic ash-limestone-water glass and a metal oxide pigment were added thereto. (1) Test materials All of the test materials, except for water glass and metal oxide pigments, were ground in a test mill and had a particle size of 149.
It was used after adjusting it to below μ. However, limestone is 88
A material less than μ was used. Glass: Glass for food containers and ordinary window glass used in ordinary households were used. Plain value (specific surface area) 3300cm ² /g. Clay: Any of slate, shale, silt, or mudstone may be used, but silty clay was used in this experiment.
Plain value 3000cm ² /g. Volcanic ash: General tuffaceous volcanic glass can be used, but in this experiment, volcanic glass from Kanoya City, Kagoshima Prefecture and Sukagawa City, Fukushima Prefecture was used. Play value 4000cm ² /g. Limestone: Common limestone used in the cement industry was used. Plain value 6300cm ² /g. Sodium silicate: Commercially available JIS No. 3 water glass was used. Pigment: A commercially available general metal oxide pigment was used. (2) Granulation Mix dry glass powder, clay powder, volcanic ash powder, and limestone powder in a specified ratio, add a specified amount of metal oxide pigment to the mixture, and mix with water or water and water glass. The mixture of
Add the mixture to a diameter of about 15% by weight.
~17mm pellets are made, and the pellets are made into 90mm pellets.
Dry at ~100°C for 3 hours. A method of using a pelletizer was also used for granulation, but in this case,
Pellets were granulated from approximately 0.2 to 15 mm. (3) Firing and cooling A box electric furnace was used for firing. The firing method involves placing the granules in an electric furnace pre-adjusted to 400°C.
The method has been unified to raise the temperature to a specified temperature at a heating rate of about 10℃ per minute and hold it at that temperature for 10 minutes.
The fired product was cooled slowly in the furnace. When firing in a rotary kiln, the temperature should be 800 to 830℃, referring to the results of firing in a box-type electric furnace.
It was fired at. In this case, no particular slow cooling was required.

【table】

〔Experimental result〕

(A) Box-type electric furnace firing (i) Limestone amount, absolute dry specific gravity, water absorption amount, and physical strength of limestone and water glass mixed fired products Depending on the type of slate, shale, silt, or mudstone clay, Because the content of foaming components such as hydrated clay minerals, microcrystalline calcite, fine iron compounds, organic substances, or fine feldspars differs, limestone powder is added as a foaming aid and the firing temperature is varied to create a large number of foaming components. I conducted an experiment. For one example, the bone dry specific gravity, water absorption and physical strength are shown in Table 1, and the bone dry specific gravity and physical strength are shown in FIG. As shown in Table 1 and Figure 1, by adding 80% glass powder to the mixed powder of clay and volcanic ash, and further adding limestone powder and water glass, both expand at a fairly low temperature. The addition effect of limestone powder was found to be positive up to 1 to 2%, but a negative effect was observed at 5% or more. Even when clay and volcanic ash are substituted, if 1 to 2% of limestone powder is added, there is almost no difference in physical properties, the absolute dry specific gravity expands to about 0.4, and the point load is as large as about 90 kg. A high-quality foam was obtained which had a fine independent cell structure inside and a dense and hard structure on the surface. The color of this foam becomes gray when the amount of glass powder is large both on the surface and inside, and when the amount of glass is reduced to 40% or less, both the surface and inside change to brown. (ii) Amount of water glass, absolute dry specific gravity, water absorption amount, and physical strength of calcined product containing limestone and water glass Based on the above experimental results, the blending ratio of limestone was set at the optimum value of 1% and 2%, and water glass was mixed. The effect of ratio on fired products was investigated. After numerous experimental results obtained by varying the firing temperature, the insulation specific gravity, water absorption and physical strength of one example are shown in Table 2, and the absolute dry specific gravity and physical strength are shown in Figure 2.

【table】

[Table] As shown in Table 2 and Figure 2, as the amount of water glass added increases, the absolute dry specific gravity decreases. The glass blending ratio is set at 80%,
In order to reduce the absolute dry specific gravity to 0.6 or less, it is necessary to add limestone powder and water glass, and when the amount of limestone powder added is 1 to 2%, the blending ratio of water glass must be 2% or more. be. (iii) Firing temperature of limestone and water glass blended fired product and absolute dry specific gravity, water absorption and physical strength of the fired product The limestone and water glass blending ratio was kept constant, the glass blending ratio was varied, and the firing temperature was 800 to 950°C. Tables 3-1 and 3-2 show the absolute dry specific gravity, water absorption, and physical strength of the fired product when the temperature was changed to It is shown in Figure 3-2.

【table】

【table】

【table】

[Table] As shown in Table 3-1-2 and Figure 3-1-2 above, if the glass blending ratio is increased,
It is a lightweight foam with a large amount of closed cells,
The absolute dry specific gravity tends to be small. physical strength
To make it 0.6 or less, the glass blending ratio should be 80% or more, and the firing temperature should be 800-900℃, preferably
It is necessary to control the temperature to 800℃. In this case, the timing of gas generation from the gas generating agent contained in the clay and the limestone powder added as the gas generating agent coincides with the optimum plasticity state (10 ⁵ to 10 ⁸ cps) of the fired material, and approximately 0.2 to 1 mm A high-quality foam having a cell diameter of 80% or less was obtained. Even if the glass blending ratio is 80% or more, if the firing temperature is increased to 950°C or higher, the air bubbles that have been generated will collapse and the absolute dry specific gravity will suddenly increase. In addition, at 850 to 900°C, the independence of bubbles tends to be somewhat lost and the number of continuous pores increases. The blending ratio of limestone is 1%, the blending ratio of water glass is 10%, and the glass blending ratio is 60~
85% and various firing temperatures, representative examples are shown in Table 3-3.
Shown below.

[Table] According to this Table 3-3, a fired product made from a mixture of 70% glass, 9.5% clay, 9.5% volcanic ash, 1% limestone, and 10% water glass has an absolute dry specific gravity of 0.50.
The point load is relatively large at 125Kg.
A high-quality foam with a fine, independent cell structure on the inside and a dense and hard structure on the surface was obtained. (B) Rotary kiln firing (i) Physical properties of fired product Based on the results of experiments using a box-type electric furnace, a number of firing experiments were conducted using a rotary kiln, and representative examples are shown in Table 4.

[Table] As shown in this Table 4, particle size is 5 to 20 cm.
The absolute dry specific gravity and water absorption of the fired product were almost the same as those obtained using a box-type electric furnace. As the particle size decreases, the absolute dry specific gravity tends to increase, but even in fired products with a particle size of 0.3 to 1.2 mm, the absolute dry specific gravity expands to 0.69, and the inside has a nearly independent fine cell structure. A hard and high quality foam was obtained. (ii) Characteristics of insulation blocks using fired products In the conventional method, biltong or mesalite is generally used as the coarse aggregate and perlite is used as the fine aggregate for the insulation blocks, but 28 days Compressive strength 180Kg
When set to f/ ^cm2 , the raw specific gravity of the block is as large as 1.5Kg/, and the thermal conductivity is 0.3~
It was not possible to reduce the temperature below about 0.4 Kcal/mh°C. In contrast, by using the fired aggregate obtained by the present invention, the raw specific gravity is approximately 1.1.
As small as Kg/, the thermal conductivity is 0.18 ~
A good heat insulation block with a small value of 0.19Kcal/mh℃ was obtained. This is shown in Table 5.

[Table] (4) Appropriate foaming conditions and physical properties of fired products Table 6 shows the appropriate foaming conditions based on the experimental results of (A) to (B) described above.

【table】

[Table] Although silty clay was used as the clay in all of the above experiments, similar results could be obtained if slate, shale, or mudstone powder was used instead of silt. Furthermore, X-ray analysis and analysis showed that the silty clay used in the above experiment was a raw material with a relatively low content of foaming components such as hydrated clay minerals, microcrystalline calcite, fine iron compounds, organic matter, and fine feldspars. This was confirmed by differential thermal analysis (DTA), and moreover, it was an attempt to obtain high strength and light weight of the fired product. In addition, as a result of numerous experiments on the powderiness of glass, clay, volcanic ash, and limestone and the physical properties of fired products, we found that the plain value (specific surface area) of each raw material
If it is about 3000cm ² /g or more, there is no problem in terms of physical properties, but in order to reduce the weight of small-particle fired products with a diameter of about 0.3 to 1.2mm, it is necessary to remove coarse particles of about 149μ or more from each raw material. It was hot. Regarding volcanic ash, see 2.
There were no physical differences in the fired products when different types of volcanic ash were used. When coloring aggregates, metal oxide pigments are added to the raw materials and an appropriate amount of sodium perborate, calcium nitrate, or potassium nitrate is added to reduce the reduction reaction of inorganic pigments co-formed during firing and melting. We have obtained knowledge that it is possible to prevent this and stabilize color tone expression. Next, examples of the artificial ultra-lightweight aggregate of the present invention are as follows. Waste glass (for example, used food and beverage containers used in ordinary households) is crushed in a mill to a plain value of approximately 3000 cm ² /g, and then shale, slate, or mudstone clay is crushed in the same way. Add limestone powder, water glass, and water to each of the above-mentioned raw material powders so that the water content is 20% by weight, and mix well. Form the mixture into pellets with a diameter of approximately 15-17 mm. If it is necessary to color the aggregate, before adding water glass and water, add an appropriate amount of metal oxide pigment and sodium perborate or calcium nitrate to form pellets, and heat the pellets at 90 to 100°C. After drying for 3 hours, the dried pellets were then fired in a firing furnace at a predetermined temperature, and the fired product was slowly cooled in the furnace to obtain an ultra-lightweight aggregate. A high-quality ultra-lightweight aggregate was also obtained by preparing pellets with a diameter of approximately 0.2 to 15 mm, drying the pellets as described above, and firing the pellets in a rotary kiln. Examples of the above method are listed below. Example 1 2 parts of water glass was added to a mixture consisting of 80 parts of glass, 8.5 parts of clay, 8.5 parts of volcanic ash, and 1 part of limestone, and then water was added so that the moisture content was 20% by weight.
After drying, the granules were granulated to a size of 17 mm, heated to 800°C at a rate of about 10°C per minute using an electric furnace, kept for 10 minutes, and then slowly cooled in the furnace to give an absolute dry specific gravity of 0.55. Water absorption
A foam with a weight of 5.2% and a point load of 85 kg was obtained. Example 2 80 parts glass, 7 parts clay, 7 parts volcanic ash, 1 part limestone
A mixture of 5 parts of water glass and 5 parts of water glass was treated under the conditions of Example 1 to obtain a foam having an absolute dry specific gravity of 0.40, a water absorption of 7.8%, and a point load of 87 kg. Example 3 A mixture consisting of 80 parts of glass, 4.5 parts of clay, 4.5 parts of volcanic ash, 1 part of limestone, and 10 parts of water glass was also treated under the conditions of Example 1, resulting in an absolute dry specific gravity of 0.29, water absorption of 9.0%,
A foam with a point load of 56 kg was obtained. Example 4 90 parts glass, 2 parts clay, 2 parts volcanic ash, 1 part limestone
A mixture of 5 parts of water glass and 5 parts of water glass was treated under the conditions of Example 1 to obtain a foam having an absolute dry specific gravity of 0.28, a water absorption of 6.8%, and a point load of 68 kg. Example 5 A mixture consisting of 80 parts of glass, 15 parts of clay, and 5 parts of water glass was treated under the conditions of Example 1, and the absolute dry specific gravity was
0.6, a water absorption amount of 8.6%, and a point load of 195 kg was obtained. Example 6 80 parts glass, 7 parts clay, 7 parts volcanic ash, 1 part limestone
A mixture consisting of 5 parts of water glass, 0.5 parts of chromium oxide, and 0.5 parts of sodium perborate was treated under the conditions of Example 1 to obtain an absolute dry specific gravity of 0.43, water absorption of 7.5%,
A green foam with a point load of 90Kg was obtained. Example 7 A mixture consisting of 80 parts of glass, 6.5 parts of clay, 6.5 parts of volcanic ash, 2 parts of limestone, 5 parts of water glass, 1 part of cobalt blue, and 0.5 part of calcium nitrate was treated under the conditions of Example 1, and the absolute dry specific gravity was determined. 0.49, a water absorption of 9.5%, and a point load of 115 kg. Example 8 A mixture consisting of 70 parts of glass, 9.5 parts of clay, 9.5 parts of volcanic ash, 1 part of limestone, 10 parts of water glass, 2 parts of titanium yellow, and 0.5 parts of potassium nitrate was treated under the conditions of Example 1, and the absolute dry specific gravity was 0.52. A yellow foam with a water absorption of 13.5% and a point load of 130 kg was obtained. As mentioned above, the artificial ultra-light aggregate according to the present invention has relatively high strength when the proportions of waste glass, clay, volcanic ash, limestone powder, and water glass are properly mixed, and when the product of the present invention is used, it has good heat retention properties. It produces high-strength lightweight concrete with excellent properties, that is, high-strength lightweight concrete, and has a wide range of uses as a colored aggregate, making it extremely useful in fields such as civil engineering, architecture, and plastering.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between the amount of limestone powder, absolute dry specific gravity, and physical strength in the fired product containing limestone and water glass, and Figure 2 is the graph showing the relationship between the amount of water glass, absolute dry specific gravity, and physical strength in the fired product containing limestone and water glass. Figure 3-1 is a graph showing the relationship between strength and strength, and Figure 3-2 is a graph showing the relationship between firing temperature, absolute dry specific gravity, and physical strength of various compounds when the amount of limestone powder is 1%. It is a graph showing the relationship between the firing temperature, absolute dry specific gravity, and physical strength of various formulations when the amount of limestone powder is 2%.

Claims (1)

[Scope of Claims] 1. Appropriate amounts of limestone powder and water glass are added to glass powder, clay powder such as slate, shale, silt, mudstone, etc., and volcanic ash (tuff), mixed, and granulated. A method for producing artificial ultra-light aggregate characterized by firing granules. 2 Glass powder at about 70-90% (weight ratio), clayey powder such as slate, shale, silt, mudstone, etc. and volcanic ash (tuff) at about 2-25%, limestone powder at about 1-5%, The firing temperature of granules is 750℃~900℃
A method for producing an artificial ultra-lightweight aggregate according to claim 1, characterized in that: 3. The method for producing artificial ultra-light aggregate according to claim 1, characterized in that a metal oxide pigment is further added as a raw material for the granules for coloring.