JP2011088125A - Far-infrared radiation material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a far-infrared radiation material in which burning process is not necessary, production cost is low and which can be stably supplied; a producing method of the same; and a far-infrared radiation material solidification. <P>SOLUTION: Particles of ≥0.15 mmϕis sifted out without burning waste casting sand. Next, isolated particles of <5 mm are cleaned by water, and irons are removed by using a wet magnetic separator. Then, by using a classifier, they are separated into washed sand of ≥0.15 mmϕ and fine particle sand of <0.15 mmϕ. Also, the fine particle sand is precipitated/concentrated in the water to obtain washed soil after being filtered by a filter press device. The washed sand or the washed soil obtained this way is a far-infrared radiation material having a high far-infrared emission rate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a far-infrared radiation material using waste casting sand as a raw material.

  Far-infrared rays are those that have a particularly long wavelength among infrared rays. According to the definition of the far-infrared rays association, far-infrared rays are considered to be electromagnetic waves with wavelengths from 3 μm to 1,000 μm. This far-infrared ray is absorbed very well by many substances other than metals (for example, plastics, paints, fibers, wood, rubber, food, ceramics, water, etc.) and becomes thermal energy. be able to. For this reason, far-infrared rays are artificially emitted by a far-infrared heater and used for heating, heating and drying of objects. Also, in heating and drying in the food field, heating by far infrared rays does not directly contact the heat source and the food, so that overheating of the food surface can be avoided. Furthermore, the energy required to raise the temperature in the deep part of the food can be given in a relatively short period of time, so it is excellent in uniform heating, making it easier to control the energy input to the food than other heating methods. There is an advantage of becoming.

In order to obtain far infrared rays, a material that emits far infrared rays is required. Roughly, all materials can emit far infrared rays more or less depending on their temperature, but their emission rates vary from material to material. In addition, far-infrared rays generated from a substance increase the energy of the far-infrared rays emitted as the temperature of the substance increases. For this reason, ceramics, natural stones, and the like that have a high far-infrared emissivity and excellent heat resistance are used as far-infrared radiation materials (Patent Documents 1 and 2). For example, ceramics with high far-infrared emissivity include Al ₂ O ₃ , SiO ₂ , MgO, ZrO ₂ , 3Al ₂ O ₃ · 2SiO ₂ (mullite), ZrO ₂ · SiO 2 (zircon), 2MgO · 2Al ₂ O ₃ · 5SiO ₂ (cordierite) etc. Moreover, black silica etc. are mentioned as a natural stone with a high far-infrared emissivity.

  On the other hand, foundry sand waste generated from the casting manufacturing process reached 1.3 million tons annually in 2003, of which 700,000 tons are recycled sand, 300,000 tons are cement materials, and 100,000 tons are roadbed materials. Although it is recycled, the remaining 200,000 tons are not yet reused and are disposed of in landfills. However, the remaining amount of landfill that can be landfilled at present is decreasing, making it difficult to construct a new final disposal site. For this reason, the technique which uses waste casting sand effectively as a resource is calculated | required.

  As a technology for using such waste foundry sand as a resource, conventionally, the waste foundry sand is baked to remove the resin component, or the impurities are removed by wet treatment (patent). Literature 3-6).

JP-A-64-69564 JP-A-6-191932 Japanese Patent Publication No.51-3690 Japanese Utility Model Publication No. 51-44727 Japanese Patent Publication No.58-19379 Japanese Patent Publication No. 1-2462

However, in the far-infrared radiation material described in Patent Documents 1 and 2, the components of the manufacturing raw material must be adjusted and the raw material must be baked and reacted in the manufacturing process, resulting in an increase in manufacturing cost. In addition, far-infrared radiation materials using natural stone with high far-infrared emissivity, such as black silica and graphite, do not require component adjustment or firing process, but the production area is limited or the output is small, There was a problem that expensive and stable supply was difficult. Also in recycling molding sand, from the viewpoint of preventing global warming, a method which does not generate C0 ₂ firing step without has been desired.

  The present invention has been made in view of such conventional circumstances, and solves the problem of providing a far-infrared radiation material that does not require a firing step, is low in production cost, and can be stably supplied, and a method for producing the same. It is an issue that should be done.

  The inventors noticed that black silica and graphite, which are well known as natural stones with a high far-infrared emissivity, are in common with the chemical components of waste foundry sand. I thought it could be. That is, the casting sand is made from silica sand, and further contains phenol resin or furan resin as a solidifying agent for forming the silica sand into a desired mold. And this resin component is heated and carbonized. For this reason, the carbon component is contained in waste foundry sand. On the other hand, black silica is a chart containing graphite in a chart (which originates from diatoms and its main component is silica), and is very similar to the components of waste foundry sand. Moreover, graphite with a high far-infrared emissivity consists of carbon, and is common with the component of waste foundry sand. For this reason, in order to actively use the carbon component that has been removed by firing treatment as an unnecessary part in the waste casting sand, it cannot be used as a far infrared radiation material without firing the waste casting sand. As a result of further intensive studies, the present invention has been completed.

  That is, the far-infrared radiation material of the present invention is characterized by comprising unfired waste foundry sand that is unfired waste foundry sand.

According to the test results of the present inventors, the far-infrared emissivity of unfired waste foundry sand is superior to SiC that has been used as a far-infrared radiation material, and much less than cordierite. There is no fading, it has excellent heat resistance, and can be used as a far-infrared radiation material. Moreover, the amount of supply of waste casting sand as a raw material is abundant. Furthermore, since non-fired waste foundry sand that is unfired waste foundry sand is used, less energy is required for production, the production cost is extremely low, and CO ₂ is reduced.

  The waste casting sand can be used as it is as long as it is unfired waste casting sand. However, it is preferable to use sieving to separate particles having a particle diameter of 0.15 mm or more. According to the test results of the inventors, this is a material exhibiting an excellent far-infrared emissivity of 90% or more.

  For this reason, in the manufacturing method of the far-infrared radiation material of this invention, it decided to provide the fractionation process of fractionating a part below a predetermined particle diameter, without baking waste casting sand.

  Furthermore, in the manufacturing method of the far-infrared radiation material of this invention, it is also preferable to provide the washing | cleaning process of washing waste casting sand with water, and the iron removal process of removing the iron contained in waste casting sand. Since the waste casting sand is washed with water in the washing process, water-soluble harmful substances contained in the waste casting sand are removed. For this reason, it becomes a far-infrared radiation material with little possibility of the elution of harmful substances. In addition, since iron is removed in the iron removal step, the far-infrared radiation material contains almost no iron and can be prevented from solidifying or being discolored red by iron rust.

  Further, the far-infrared radiation material of the present invention may be hardened with a solidifying material such as cement. This facilitates handling of the far infrared radiation material. Here, examples of the solidifying material include organic polymer compounds such as sodium alginate, acrylic superabsorbent resin, and polyvinyl alcohol resin, and inorganic powder such as magnesium oxide.

The far-infrared radiation material of the present invention can be used in various fields of industry.
For example, the far-infrared radiation material of the present invention can be applied to a road and used as a snow melting agent, or can be applied to agricultural land and used to keep soil warm. Moreover, the board | plate material solidified with cement etc. can be used as a raw material of a floor heating or a bedrock bath. Also, mix the flooring or wall materials, such as houses and factories and barns, by improving the heating efficiency, reduce energy consumption, it is also possible to contribute to reducing CO ₂ emissions. Furthermore, it is used as a material for far-infrared heaters, and it is used for painting and drying of metal products, resin products, furniture woodwork, etc., and for metal products, plywood, wood products, paper, cloth, electrical / electronic equipment parts, etc. Used for drying printing, used for moisture drying of wood, fibers / textiles, paper / pulp, chemicals / chemicals, etc., used for drying after washing metal products, drying and curing raw materials for resin, rubber and leather It is used for vulcanization, glass, building materials and ceramic raw materials and dough drying, preheating, printing drying, glaze preheating, adhesion, etc. It may be used for circuit drying, exterior printing / coating drying, sealing of package elements, baking, solder reflow, etc., heating, dry sauna, thermal treatment, and hair dryer. Also, in the food industry field, it is used for drying seaweed, cereals, tea, vegetables, fruits and processed foods, used for the production of dried fish and dried fish and shellfish, hardening and metamorphosis of noodles and pastes, beans and cereal powders Used for the transformation of food (heat treatment), baking bread, rice crackers, baked salmon and grilled chestnuts, used for baking chikuwa, salmon, meat, seafood, etc., roasting tea, burning, coffee It may be used for roasting / roasting beans, nuts, sesame seeds, etc., used for heat preservation of cooked foods, thawing frozen foods, etc., and for drying / concentration / aging of liquid foods / beverages. Moreover, it can also install in heating parts, such as a grill, an oven toaster, a rice cooker, and can also heat by far infrared rays.

(Embodiment)
As the waste foundry sand used as the raw material of the far infrared radiation material of the present invention, waste foundry sand used for iron castings, aluminum castings, copper alloy castings and the like can be used. Among these, an iron casting is particularly preferable. In an aluminum casting or a copper alloy casting, there is a possibility that aluminum or a copper alloy may be mixed into the adsorbent. Moreover, it is because a copper alloy may contain harmful heavy metals, such as lead.

  In addition, the casting sand mold includes a raw sand mold containing silica sand, clay, starch, vegetable oil, carbon and the like, and an organic sand mold containing an organic binder resin such as quartz sand, phenol resin and furan resin. Can also be used as a raw material.

From the waste foundry sand collected from the foundry, large solids are first removed by a screen or the like. The removed solid matter may be pulverized with a rod mill or the like and classified again with a screen. The waste foundry sand from which large solids have been removed in this manner is washed with a spiral washing machine or the like, and iron is removed with a magnetic separator. Further, it is sieved by a classifier and classified into sand having a particle size of 0.15 to 5 mm and fine sand having a particle size of less than 0.15 mm. Washed sand is drained and stored in the stockyard. Thus, the sand can be obtained. The fine sand is stirred and concentrated with a thickener and then dehydrated by a dehydrator such as a filter press to obtain a cake-like soil-washed product having a water content of about 30 to 50% by mass.
The sand-washed product thus obtained is an infrared radiation material having a particle size of 0.15 to 5 mm.
Further, the thus obtained soil-washed product is an infrared radiation material having a particle diameter of less than 0.15 mm.

  Examples that further embody the present invention will be described below.

Example 1
<Solid matter removing step S1>
As shown in FIG. 1, first, as a solid matter removing step S1, waste foundry sand discarded from an iron foundry is collected, passed through a two-stage screen of 50 mm and 5 mm, and impurities such as glass, metal, and brick are removed. Remove and fractionate a part with a particle size of less than 5 mm. About a classification | category part of 5-50 mm, it crushes to the particle diameter of less than 5 mm with a rod mill, and is set as the particle diameter of less than 5 mm.

<Washing step S2>
Next, as washing process S2, particles less than 5 mm separated in the solid matter removing process S1 are sent to a spiral washing machine, and water washing is performed.

<Iron removal process S3>
Furthermore, irons in the particles of less than 5 mm cleaned by the cleaning step S2 are removed using a wet magnetic separator.

<Sieving step S4>
And using a Bible classifier, it is divided into a sand-washed product of 0.15 mmφ or more and a fine sand of less than 0.15 mmφ.

<Filter press step S5>
Further, the fine sand obtained in the sieving step S4 is sent to a thickener, and concentrated and precipitated with slow stirring in water. The resulting fine sand slurry is filtered with a filter press to obtain a purified soil washing product. It was.

The soil washing product thus obtained is an infrared radiation material having a particle diameter of less than 0.15 mm.
The sand-washed product obtained in the sieving step S4 is an infrared radiation material having a particle size of 0.15 to 5 mm.

<Evaluation>
The soil-washed product and sand-washed product obtained as described above were solidified with a small amount of cement in order to evaluate as an infrared emitting material, and the infrared emissivity was measured. The details are shown below.

(Manufacture of far infrared radiation measurement samples)
90 parts by weight of the above sand-washed product, 10 parts by weight of ordinary Portland cement, and 35 parts by weight of water were mixed and molded into a plate shape of 50 × 50 × 5 mm. Then, for 2 weeks, sealed curing was performed, followed by water curing for 1 week, and finally, sample 1 subjected to air curing for 1 week was used for far infrared radiation measurement.

  Further, 85 parts by weight of the above-mentioned soil-cleaning product, 15 parts by weight of ordinary Portland cement, and 50 parts by weight of water were mixed, formed into a plate shape of 50 × 50 × 5 mm, and cured in the same manner as in the production of Sample 1. Sample 2 was used for far infrared radiation measurement.

  The far-infrared emissivity was measured according to JIS R 1801. The basic configuration of the measuring device is FTIR (Fourier Transform Infrared Spectrophotometer) that measures the infrared radiation spectrum, the sample heating device that controls the surface temperature of the sample by heating the sample from the back surface, and when calculating the spectral emissivity It consists of a blackbody furnace that emits blackbody radiation used as a reference spectrum. The sample was heated from the back of the sample so that the surface temperature was 100 ° C. or higher and lower than 300 ° C., and measured in the wavelength range of 4 to 20 μm.

(Measurement result)
The measurement result about the sample 1 manufactured from the sand-washed product is shown in FIG. Moreover, the measurement result about the sample 2 manufactured from the soil-cleaning goods is shown in FIG. From FIG. 3, it was found that Sample 1 produced from the sand-washed product showed a high far-infrared emissivity of 90.6% on average. It was also found that Sample 2 produced from the soil-washed product also showed a high far-infrared emissivity of 86.51% on average. Note that the emissivity of both samples decreased from 4 μm to 6 μm, which is considered to be due to the silica content contained in the waste casting sand.

  Table 1 shows the comparison of the far-infrared emissivity of Sample 1 and Sample 2 with the measured values of other far-infrared radiation materials (Source: All of far-infrared ceramics: Optronics, 1989.2). From this table, although sample 1 and sample 2 do not reach cordierite, they have a larger value than SiC (0.844) conventionally used as a far infrared radiation material, and have a high far infrared emissivity. You can see that

  The present invention is not limited to the description of the embodiments and examples of the invention described above. Various modifications are also included in the present invention as long as those skilled in the art can easily conceive without departing from the scope of the claims.

It is a manufacturing-process figure of the far-infrared radiation material of the sample 1 and the sample 2. FIG. 4 is a graph showing the measurement results of far-infrared emissivity of Sample 1. 6 is a graph showing the measurement results of far-infrared emissivity of Sample 2.

S1 ... Solid matter removal step S2 ... Washing step S3 ... Iron removal step S4 ... Preparative step S5 ... Filter press step

Claims (5)

  A far-infrared radiation material comprising unfired waste foundry sand which is unfired waste foundry sand.   The far-infrared radiation material according to claim 1, wherein the particle diameter is 0.15 mm or more.   A method for producing a far-infrared radiation material, comprising a fractionation step of fractionating a portion having a predetermined particle size without firing waste foundry sand. Furthermore, a washing process for washing waste casting sand with water,
An iron removal process for removing iron contained in waste foundry sand;
The manufacturing method of the far-infrared radiation material of Claim 3 characterized by the above-mentioned.   A far-infrared radiation material solidified product obtained by solidifying the far-infrared radiation material according to any one of claims 1 to 3 with a solidifying material.

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