JPS642159B2 - - Google Patents

Description

[Detailed description of the invention]

Snow melting materials that improve atmospheric heat transfer,
It can be roughly divided into those that absorb solar heat, those that use running water, and those that lower the freezing point. Among the above, the one of this invention is a snow melting material made of fine particles that improves atmospheric transfer heat and absorbs solar heat, and its production. It relates to a method for spraying rice fields, fields, pastures, golf courses, other grounds, roads, etc. Conventionally, factory-produced graphite, carbon black, other charcoal powder, rice hull charcoal, etc. have been used as solar heat absorbing snow melting materials, and the bulk specific gravity is often around 0.7 to 1.00, and the particle size distribution is However, those containing a considerable amount of less than 200 mesh are used. Since these materials are lightweight, they are relatively easy to transport to the site, but they have a high scattering rate and are inefficient, and the black scattered powder is harmful to workers, nearby residents, and homes. There is a risk of inhalation, and because it is black, it can contaminate the human body, clothing, neighboring houses, and laundry, so it cannot be used near people's homes, and its usage is limited. Moreover, since it is lightweight, it is easy to be washed away with snow melting water, which not only reduces the effect of snow melting afterward, but also causes pollution that pollutes the water black if it flows into rivers. There are products on the market that contain freezing point depressants to further improve the snow melting effect, such as carbon black, but products mixed with industrial chemicals are not only extremely expensive, but also because these chemicals are used in agricultural products. Not only does it have a big impact on household savings, but
The problem of black contamination still remains unsolved, and combined with the high cost, it is not widely used. In recent years, there has been a call for an increase in grain production to match the increase in the world's population, and even in Japan, it is predicted that there will be a global shortage of wheat in the future, so there is a need to switch from rice cultivation to wheat cultivation. However, in areas with heavy snowfall, root snow melts slowly, especially in the case of wheat cultivation, if it remains under snow for more than 100 days after sowing.
The seeds rot and there is no hope for further growth, so it is necessary to melt the snow in early spring, especially in early March, but it takes time for the root snow to naturally melt, so the advent of an inexpensive artificial snow melting agent is long awaited. ing. Therefore, the inventor sought to develop snow melting materials that are inexpensive, have low reflectance, and have uniform quality.
It has a certain gravity and does not scatter during spraying, does not deteriorate the working environment due to black pollution, does not cause pollution, and is not only harmless to humans, but also has an impact on the ecosystem of cultivated plants, forests, and nearby flora and fauna. It has been found that it can be manufactured by subjecting used foundry sand to some processing so that it meets the condition of not giving it. That is, we have developed a snow melting material that uses used foundry sand (waste sand), which is produced as a by-product when casting products, as a starting material. The foundry sand that is generally used when manufacturing castings is silica sand, which is mixed with an appropriate amount (about 4%) of a binder (phenol or furan resin), a mold is made, and the binder is hardened. After injecting molten metal and solidifying the metal in the mold, the mold made of foundry sand is crushed and the casting is taken out and finished into a product. On the other hand, most of the crushed foundry sand is recovered and reused, but when the silica sand itself is exposed to the heat of molten metal, it undergoes thermal shock, causing cracks in the silica sand and making it finer. Since the air permeability deteriorates when reused to make a mold, generally this finely divided sand is sieved and new sand is replenished accordingly, or some of the sand is replaced with new sand without sieving. Since the old sand is disposed of as waste, a large amount of used foundry sand is produced as industrial waste from foundry manufacturing. However, since this old foundry sand has a binder attached to it, it is harmful to agricultural crops and pastures if left as is, so until now it has only been used to a small extent as an aggregate for asphalt pavement, and has been mostly used. They were disposed of in landfills at the foundry's expense. The inventor of this application aims to provide the market with a product that has the desired effect as a snow melting material using old foundry sand, which is industrial waste produced in large quantities, as a starting material, and to make this product easy to manufacture. belongs to. This invention is natural sand whose grains are baked and coated with a type of thermosetting synthetic resin such as carbonized furan resin or phenolic resin, and whose particle size distribution is from 35 to 200.
It is a snow melting material characterized by containing more than 95% of snow melting material. Another invention is sand whose grains are baked and coated with a type of thermosetting synthetic resin such as carbonized furan resin or phenolic resin, and whose particle size distribution ranges from 35 to 200.
The weight ratio of mesh is about 80 to 90%, about 10 to 90%
A snow melting material, characterized in that it contains a mixture of about 20 to 10% by weight of at least one of the following: natural sand with a particle size of 25 mesh, coal powder, Kupora granulated slag for cast iron, and calcium silicate fertilizer. It is. In another invention, used foundry sand coated with a type of thermosetting synthetic resin such as furan resin or phenolic resin is heated to 400° to 800°C in an oxygen-poor atmosphere to carbonize the synthetic resin. This is a method for producing a snow melting material whose main material is granular sand, which is dispersed in particles and has a particle size distribution of 35 to 200 mesh, containing 95% or more. First, the method for manufacturing the snow melting material of this invention will be explained. First, as a starting material, use old foundry sand (including some unused sand mixed in) without supplying oxygen, or
After heating to 400° to 800°C in a small state to sufficiently carbonize one type of thermosetting resin among furan resin and phenolic resin on the sand surface, the solidified mold was crushed. Got the product. The particle size distribution of the product thus obtained is as shown in Table 1.

【table】 Its chemical composition is shown in Table 2.

[Table] The difference in content of SiO ₂ , Al ₂ O ₃ , etc. in the table above is due to the fact that the foundry sand itself is originally made from natural river or sea sand, and there is considerable variation in its chemical composition. Although the content of C is small in terms of the overall content, since carbide is formed on the surface of each sand grain, it has a dark brown appearance. Next, the above products were sent to the Environmental Agency, Water Quality Conservation Bureau, Director-General, 1975.
Circular Kansuikan No. 120 dated October 28, 2018 (bottom sediment survey method)
Based on the above, the content of hazardous substances is inspected, and the elution of hazardous substances is also inspected according to the Environment Agency's Environmental Notice No. 13 dated February 17, 1971 (Method for testing hazardous substances contained in industrial waste JIS A1102). The results of the tests were shown in Table 3 below. Clark's number is also included as a reference material.

[Table] As shown in Table 3, the overall content of harmful substances is lower than that of normal soil, no elution of harmful substances has been detected, and the pH is neutral, so it can be used for crops, trees, etc. Of course, hoarding is harmless. What is shown in Tables 1 to 3 above is one embodiment of the specific invention. Next, an embodiment of the second invention will be shown. The main material is the product of the above-mentioned specified invention, and this
90%, to which is added 20% to 10% of Kupora granulated slag for cast iron, with a particle size of about 10 to 25 mesh. The chemical composition of this Kupora granulated slag is generally as shown in Table 4.

[Table] The amount of elution of pollutant and harmful substances was tested using the JIS A1102 method, and the results are shown in Table 5 below.

[Table] An example of the fertilizer components of this Kewpora granulated slag tested using the fertilizer analysis method is shown in Table 6 below.

[Table] Therefore, it can be fully used as a calcium silicate fertilizer. In an embodiment of the present invention, the raw material is obtained by sifting particles having a particle size of about 10 to 25 mesh from the above-mentioned Kupora granulated slag. As mentioned above, the 10 to 20% addition of 10 mesh particles does not contain any harmful substances and can be considered as a calcium silicate fertilizer addition. It is harmless to storage. Next, the effects of the first invention and the second invention when used as snow melting materials are shown below. First, Table 7 shows the results of measuring the reflectance of the Cewpora granulated slag added to the product of the specific invention and the product of the first invention. Amounts equivalent to 30, 50, 70, and 100 kg were sprinkled on white paper over an area of 10 ares, and the reflectance was determined using a pyranometer.

【table】

[Table] Figure 1 is a graph of this table. Next, the results of the snow melting effect experiment are shown. The product of the specific invention is expressed as black material 1 due to its appearance color, and the Kyupora granulated slag, which is an embodiment of the second invention, is similarly expressed as white material 2, and the amount of spraying is 30,
Experiments were conducted by spraying amounts equivalent to 50, 70, 100, and 200 kg.
In the experiment, artificial snow was placed in a Styrofoam box (30cm x 50cm x
Figure 2 is a graph showing the results of an experiment conducted in a glass room with natural light, with snow melting material sprinkled on the surface and a maximum temperature of 0 to 3 degrees Celsius during the day and -1 to -5 degrees Celsius at night. In addition, Table 8 shows the melting snow accumulation when black wood, white wood, and a mixture thereof were sprinkled into the box in an amount equivalent to 70 kg per 10 arms.

[Table] ○ Mixing ratio is weight ratio As is clear from the above analysis and experimental results, firstly, in the specific invention, there is a sensible heat effect due to the physical absorption of solar heat and the formation of unevenness on the snow surface by powder. Because it takes advantage of physical properties such as an increase in Unlike those that utilize chemical properties such as melting point depressants, there is no harm caused by chemical reactions, and it is odorless and neutral, and does not pollute farmland, mountains, forests, and rivers with snowmelt water.
Hoarding is harmless. Furthermore, since the carbide or carbon itself of a type of thermosetting synthetic resin among furan resin and phenolic resin is strongly baked onto the surface of each particle, hands and clothes will not get dirty even if they touch this snow melting material. Therefore, even if it gets on people's bodies or clothes during spraying, it will not stain them and will not pollute rivers. It is also possible to spread with a spreader, which makes it easy to work. In addition, because of its high specific gravity, it can be effectively sprayed on the target snow surface without being scattered by the wind when spraying, unlike conventional carbon black or graphite-based sprayers. Spraying is also possible as long as there are no extremely strong winds, and there are many days when the weather is suitable for spraying, making it possible to spray at the optimal time. In addition, in the case of materials with particle size distribution as described above, this snow melting material tends to remain on the surface of the snow even during the snow melting process, and does not flow out and has a snow melting effect during the entire snow melting period. Demonstrate. (See Figure 3). In addition, in the second invention, about 10 to 20% by weight of one of natural sand, coal, granulated cupora slag for cast iron, calcium silicate, and fertilizer with a large particle size is mixed. Therefore, when the snow melts, the vicinity of these large particles melts quickly and creates a large dent (see Figure 4), increasing the surface area of the snow surface.
The absorption rate of solar heat increases as the reflected light hits other snow surfaces, and the increased surface area also increases the area of contact with the wind, increasing the sensible heating effect. It also has the effect of being a type of calcium silicate fertilizer. Therefore, it is particularly useful for melting snow on rice fields. If the mixed particles are too large, they will sink too quickly and the effect will be diminished, and if the particles are too small, the reflectance will be reduced. The reflectance also decreases when the mixing rate is high. Next, in the method of this invention, furan resin,
Since the starting material is used foundry sand coated with a type of thermosetting synthetic resin among phenolic resins, not only can industrial waste be effectively used, but it can also be heated to temperatures between 400℃ and 800℃ in a low oxygen condition.
The phenols contained in the phenolic resin used as a binder for foundry sand,
Formaldehyde and other free solvents can be completely volatilized and rendered harmless, and because the grain size of used foundry sand was originally selected, thermal shock causes it to become finely pulverized, making it unsuitable for use as foundry sand. However, as shown in Table 1 above, more than 98% of the particles are within the particle size range of 35 to 200 mesh,
There are almost no finer particles, so it can be used almost as is as a snow melting material without any special sieving after firing and breaking the mold shape. Furthermore, a carbonized layer of synthetic resin can be firmly attached to the surface of the grains of old foundry sand. If the heating temperature is 400° C. or higher, harmful substances will remain and carbonization will be insufficient, and long-term heating will be required to achieve sufficient carbonization, resulting in poor thermal efficiency and reduced productivity. Furthermore, if the temperature is 800°C or higher, there is a risk that the carbonized layer will burn, making it extremely difficult to control the heating time. In the embodiment of the second invention mentioned above, both the black wood and the white wood are made from industrial waste, and by using them in a mixture, the effect is much greater than when each is used individually. Demonstrates excellent snow melting effects. Regarding the mixing of coal powder and natural sand other than the above-mentioned embodiments, if 10 to 25 mesh of coal powder is mixed, since the coal powder itself is black, the reflectance will decrease and the absorption of solar heat and sunlight will be enhanced. Effective, but causes some black staining. Natural sand, calcium silicate fertilizer, particle size 10
The mixture containing 1 to 25 mesh had almost the same effect as the aforementioned mixture of Kyupora granulated slag.

[Brief explanation of the drawing]

The drawings relate to this invention, and FIG. 1 is a graph showing the relationship between the amount of spraying and reflectance, and FIG.
A graph showing the relationship between the amount of spraying and snow reduction depth, Figure 3 is of the specified invention; an enlarged vertical cross-sectional view showing the state of snow melting;
FIG. 4 is an enlarged vertical sectional view showing the state of snow melting according to the second invention. Code: 1...black wood, 2...white wood, 3...snow.

Claims (1)

[Scope of Claims] 1. Natural sand whose grains are baked and coated with a type of thermosetting synthetic resin among carbonized furan resins and phenolic resins, which contains 95% or more of particles with a particle size distribution of 35 to 200 mesh. A snow melting material that is characterized by 2. Sand whose grains are baked and coated with a type of thermosetting synthetic resin such as carbonized furan resin or phenolic resin, and whose particle size distribution is about 80 to 90% by weight and about 10 to 200 mesh. A snow melting material, characterized in that it contains a mixture of about 20 to 10% by weight of at least one of the following: natural sand with a particle size of 25 mesh, coal powder, Kupora granulated slag for cast iron, and calcium silicate fertilizer. . 3 Used foundry sand coated with a type of thermosetting synthetic resin such as furan resin or phenolic resin is heated to 400° to 800°C in an oxygen-poor atmosphere to carbonize the synthetic resin and disperse it into particles. A method for producing a snow melting material whose main material is granular sand containing 95% or more of particles with a particle size distribution of 35 to 200 mesh.