JP4991638B2 - Production method of foam glass - Google Patents

Description

  The present invention relates to a method for producing foam glass.

There has been proposed a technology for converting waste glass into foamed glass to effectively use resources (for example, see Patent Document 1).
JP 2005-132714 A (Claim 2)

Claim 2 of Patent Document 1 states that “a crushed glass and at least one component selected from the group consisting of calcium hydroxide, calcium oxide, calcium phosphate, calcium sulfate, calcium carbonate, ferric oxide, ferric sulfate and activated carbon; ,
Melting and foaming at a temperature of 700 ° C. to 1100 ° C., and
At least one component selected from the group consisting of calcium hydroxide, calcium oxide, calcium phosphate, calcium sulfate, calcium carbonate, ferric oxide, ferric sulfate and activated carbon is dispersed in the foamed glass to be produced. The manufacturing method of foam glass. Is described.

  That is, Patent Document 1 is to mix a “foaming agent” composed of a group of calcium hydroxide, calcium oxide, calcium phosphate, calcium sulfate, calcium carbonate, ferric oxide, ferric sulfate and activated carbon into crushed glass. The present invention relates to a technology for producing foamed glass characterized by

That is, in the conventional technology, the procurement cost of the foaming agent is indispensable, and this is a factor that increases the manufacturing cost of the foamed glass.
Therefore, reduction of the manufacturing cost of foam glass is required.

In addition, the body of an automobile is painted or plated, and the paint or plating contains a chromium-based substance. When this chromium-based substance is heated at 700 ° C. or higher and 1100 ° C. or lower, there is a possibility that it is changed to toxic hexavalent chromium with an oxidation reaction.
In the technique of Patent Document 1, no countermeasure is taken.
Therefore, countermeasures against hexavalent chromium are required.

  This invention makes it a subject to provide the technique which can take the hexavalent chromium countermeasure while being able to reduce the manufacturing cost of foamed glass.

The invention according to claim 1 is obtained by cutting a used car, a shredder dust called ASR contain chromium-based material as a starting material, subjected to selection by processing in the starting material, the glass particles In the method for producing foamed glass, which obtains foamed glass by obtaining a crushed powder mixed with an appropriate amount of resin particles and subjecting this crushed powder to a baking treatment,
The firing process includes a plurality of steps, and these steps are:
Filling the crushed powder into a container without a lid;
In order to heat from the upper surface of this container and prevent air from entering and leaving the space where the filled crushed powder is placed and the outside, an upper surface heating step of forming a glass layer on the crushed powder ,
A heating step of obtaining foamed glass by melting the glass particles contained in the glass layer by heating the container as a whole and using the resin particles as a foaming agent. And

In the invention according to claim 1, an appropriate amount of resin particles remains in the crushed powder. This resin grain contains abundant carbon (C) and calcium carbonate (CaCO ₃ ). Carbon is oxidized to carbon dioxide when heat is applied. When heat is applied to calcium carbonate, it decomposes and generates carbon dioxide. This carbon dioxide gas becomes the foaming gas.

That is, according to the present invention, it is not necessary to add a foaming agent separately, and it becomes possible to produce foamed glass only with ASR.
According to this invention, since it is not necessary to procure a foaming agent, the manufacturing cost of foamed glass can be reduced.

In addition, at the initial stage of the firing step, only the upper surface is heated to form a glass layer. This glass layer serves as a barrier layer that prevents air from entering and exiting. For this reason, it is possible to prevent the chromium-based material from being transformed into hexavalent chromium.
According to the present invention, it is possible to provide foamed glass that does not contain hexavalent chromium.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a basic manufacturing flow diagram of foam glass according to the present invention, in which equipment such as an engine, transmission, airbag, tire, battery, fuel, and oil are removed from a used automobile (ST01). Next, it cuts with a shredder (ST02). The obtained shredder dust is generally called ASR (Automobile Shredder Residue).

  The obtained ASR is subjected to sorting processing by applying a known sorting method such as specific gravity sorting (ST03). Although this processing method will be described in detail in the next figure, a tertiary earth and sand glass can be obtained by applying this treatment to earth and sand glass (first and second earth and sand glass). The tertiary earth and sand glass is heated to about 600 ° C. to perform a temporary firing process (ST04). Thus, a temporarily fired body can be obtained, and the temporarily fired body is heated to about 800 ° C. to perform the main firing process (ST05). Thereby, foamed glass can be obtained. Details of the pre-baking process of ST04 and the main baking process of ST05 will be described later.

FIG. 2 is a flowchart for explaining processing such as sorting in detail, and step numbers (ST) are numbered from 11 for convenience. FIG. 3 is a drawing supplementing FIG.
As shown in FIG. 3A, the ASR is composed of, for example, 55% by mass of resin, 20% by mass of metal, and the remaining earth and sand glass (with earth and sand attached to glass).

  From such ASR, most of ferrous metals are excluded by well-known magnetic sorting method, non-ferrous sorting method and specific gravity sorting method, most of non-ferrous metals such as aluminum and copper are excluded by non-ferrous sorting method, Most of them are excluded (ST11). Thus, the primary earth and sand glass is obtained.

  Resin, metal, earth and sand that could not be separated by well-known sorting remain because the resin molding and the antenna are firmly bonded to the glass and the dust is firmly attached. Therefore, as shown in FIG. 3B, the primary earth and sand glass is composed of, for example, 6.3% by mass of resin (residual resin), 12.9% by mass of metal (residual metal), and glass (residual). Including the amount of earth and sand).

Such primary earth and sand glass is crushed (ST12).
This crushing is performed by a blade crusher, a ball mill crusher or other crushers. The principle of the blade crusher is explained in the following figure

  FIG. 4 is a principle diagram of the blade crusher. The blade crusher 10 passes through a base 11 having a built-in motor, a container 12 mounted on the base 11, and a bottom of the container 12. And a crushing blade 14 mounted horizontally on the motor shaft 13 and a lid 15 that closes the upper opening of the container 12.

A primary earth and sand glass 16 indicated by an imaginary line is placed in the container 12. Cover with lid 15,
The crushing blade 14 is rotated horizontally at high speed. Then, the crushing blade 14 collides with the first earth and sand glass 16 and starts crushing and the like.

The primary earth and sand glass 16 contains residual metal, residual resin, residual earth and sand, and glass shown in FIG.
Among them, the residual metal is hard and is not crushed. Since the residual resin is soft, it is shaved and separated into shavings and the remaining resin. Naturally, the shavings are small and the remaining resin is large.
The remaining soil and glass are crushed.

The first sieve is applied in ST13 of FIG. Residual metal and residual resin remain on the sieve. On the other hand, resin shavings, glass particles and earth and sand fall through the sieve. The part which fell is called the secondary earth and sand glass. Resin shavings are called re-residual resin.
That is, when the crushed earth and sand glass is passed through the first sieve, all of the residual metal and most of the residual resin are separated and excluded. And the secondary earth and sand glass which consists of the remaining glass grain, a re-residue resin, and residual earth and sand is obtained.

In ST14, the second earth and sand glass is passed through the second sieve. The second sieve has smaller eyes than the first sieve.
Residual resin having a too small particle size, glass particles having a too small particle size, and earth and sand having a too small particle size pass through the second sieve and are excluded. The moderately sized glass particles, the re-residue resin and the residual earth and sand remaining on the second sieve are referred to as tertiary earth and sand glass.
As shown in FIG. 3C, the tertiary earth and sand glass is composed of 0.1 to 3% by mass of a residual resin and glass particles (including residual earth and sand).

  The particle size of the tertiary earth and sand glass is preferably in the range of 50 to 500 μm, and most preferably 250 μm. The first sieve mesh (mesh) and the second sieve mesh (mesh) are determined so as to obtain such a particle size.

  Next, the case where a ball mill type crusher is used instead of the blade type crusher at ST12 in FIG. 2 will be described. A ball mill type crusher is a device that puts a lot of hard balls inside a rotating drum and crushes the primary earth and sand glass with these balls, and its crushing performance is much higher than that of a blade type crusher. Therefore, when the primary earth and sand glass is crushed with a ball mill type crusher, most of the soft resin may be finely crushed.

Most of the finely crushed resin passes through the first sieve and the second sieve. As a result, there is a possibility that the ratio of the resin occupied in the tertiary earth and sand glass is significantly lower than the resin ratio of 0.1% by mass shown in FIG. This makes the resin ratio too low.
Therefore, when adopting a ball mill type crusher, it is necessary to devise such as shortening the crushing time so that the resin ratio becomes 0.1% by mass or more, and the crushing work becomes troublesome.
In this respect, a blade-type crusher is preferable because the crushing time can be sufficiently secured and the crushing operation becomes easy.

Next, the pre-baking process performed on the obtained tertiary earth and sand glass will be described.
FIG. 5 is a flowchart for explaining the pre-baking process, and FIG.
As shown in FIG. 6A, in the third earth and sand glass 20, resin particles (re-residual resin whose particle size is adjusted) 22 are mixed between the glass particles 21 and the glass particles 21. Sediment grains were omitted.

  By the way, generally a plasticizer, a stabilizer, a filler, and other additives are added to the resin. Among them, the filler is a mixture for saving resin raw materials. A typical example of the filler is calcium carbonate.

  If the tertiary earth and sand glass 20 shown in FIG. 6A is baked at about 800 ° C. for 60 minutes, the glass particles 21 are melted and the calcium carbonate contained in the resin particles 22 is reduced. It is thermally decomposed into calcium (calcium oxide) and carbon dioxide. As a result, large bubbles 101 are generated in the glass 102 as shown in FIG.

  Compared to the case where a large number of small bubbles are dispersed, the bubbles 101 are inevitably unevenly distributed when the bubbles 101 have a large diameter. Therefore, the quality of the foam glass 103 shown in (b) is low. It is required to improve the quality, and the method will be described below.

  In FIG. 5, the tertiary earth and sand glass is temporarily fired at about 600 ° C. (ST15). Thus, a temporarily fired body can be obtained. As shown in FIG. 6B, the temporarily fired body 25 is obtained by mixing carbon particles 26 between the glass particles 21 and the glass particles 21. That is, the resin particles 22 were baked and carbonized. Such a pre-fired body 25 is fragile unlike the main fired body. Therefore, the temporarily fired body 25 can be finely crushed (ST16).

By this crushing, the carbon particles 26 are also crushed into small particles. As shown in FIG. 6D, the obtained crushed powder 30 is obtained by dispersing small particles 31 of carbon between the glass particles 21 and the glass particles 21.
When the crushed powder 30 is baked at about 800 ° C., a high-quality foamed glass 34 in which a large number of bubbles 33 are appropriately dispersed in the glass 32 as shown in FIG. 6E can be obtained.

  That is, the tertiary earth and sand glass 20 shown in FIG. 6A is not immediately fired (mainly fired), but is subjected to a temporary firing process, and the obtained temporary fired body is finely crushed, and the obtained crushed material is obtained. By subjecting the powder to a main baking treatment, a high-quality foam glass 34 in which bubbles are evenly dispersed can be obtained.

  At this time, it is not necessary to add a foaming agent such as calcium carbonate. That is, the resin particles 22 contained in the tertiary earth and sand glass 20 were used as substitutes for the foaming agent. As a result, it is not necessary to procure a foaming agent, and the manufacturing cost of foamed glass can be reduced.

Incidentally, chromium (Cr) and trivalent chromium (Cr ⁺³ ) are mixed in paint and plating applied to the body of an automobile. It is expected that a part of such chromium (Cr) or trivalent chromium (Cr ⁺³ ) is mixed in the crushed powder 30 shown in FIG. It is known that chromium (Cr) and trivalent chromium (Cr ⁺³ ) are oxidized and changed to toxic hexavalent chromium.
It is necessary to prevent the generation of this toxic substance, hexavalent chromium. In other words, instead of the process of FIG. 6D to 6E, the process described below is recommended.

FIG. 7 is a diagram for explaining the main baking process. In (a), the crushed powder 30 is filled into the lidless container 35 whose upper surface is open. The crushed powder 30 includes glass particles 21, small carbon particles 31, and a chromium-based material 36. The chromium-based material 36 is chromium (Cr), trivalent chromium (Cr ⁺³ ), or a mixture thereof.

Next, as shown in (b), heating is performed at about 800 ° C. from above the lidless container 35. Then, the glass particles on the upper surface are melted to form the glass layer 37. After this, the small particles 31 of carbon combine with surrounding oxygen (O ₂ ) and change to carbon dioxide (CO ₂ ).

Since this reaction is performed in a sealed space, the space below the glass layer 37 is an oxygen-free atmosphere or a reducing atmosphere. Chromium (Cr) or trivalent chromium (Cr ⁺³ ) placed in an oxygen-free atmosphere or reducing atmosphere does not proceed with oxidation, so there is no ^fear of changing to hexavalent chromium (Cr ⁺⁶ ).

Therefore, as shown in (c), the main baking is performed from the periphery of the lidless container 35 as a whole at about 800 ° C. By heating at this time, the glass particles become molten glass 38, and the bubbles 39 of carbon dioxide gas are dispersed therein. These bubbles 39 are further expanded by heating.
The foamed glass 40 obtained by cooling after the main baking treatment includes a large number of bubbles 42 in the glass 41 as shown in FIG. The chromium-based material 36 is contained in the form of harmless chromium (Cr) or trivalent chromium (Cr ⁺³ ).

The main firing process described in FIG. 7 is summarized in the form of a flow.
FIG. 8 is a flowchart for explaining the main baking process, in which crushed powder is filled into a container without a lid (ST17), and the upper surface is heated (ST18). As a result, a glass layer is formed, and a reducing atmosphere is formed under the glass layer. Next, the whole is heated at about 800 ° C. (ST19). Then, carbon dioxide (CO ₂ ) expands, bubbles are evenly dispersed, and foamed glass containing chromium in the form of harmless chromium (Cr) or trivalent chromium (Cr ⁺³ ) is obtained. it can.

In the above description, the pre-baking temperature is about 600 ° C. and the main baking temperature is about 800 ° C., but the pre-baking temperature is selected from an appropriate temperature lower than the melting point (500 to 650 ° C.) based on the melting point of the automotive glass. The main firing temperature may be an appropriate temperature higher than the melting point (a temperature selected from 700 to 900 ° C.).
Moreover, the main baking time is preferably 60 to 180 minutes, and most preferably 60 minutes.

  Whether the third earth glass obtained by the method of the present invention is immediately fired (about 800 ° C.) to obtain foamed glass, or is provisional fired after provisional firing, to obtain foamed glass. Is optional.

  The present invention is suitable for a technique for producing foamed glass from shredder dust called ASR.

It is a basic manufacturing flowchart of the foam glass which concerns on this invention. It is a flow figure explaining processing, such as sorting, in detail. It is drawing which supplements FIG. It is a principle diagram of a blade type crusher. It is a flowchart explaining a temporary baking process. FIG. 6 is a supplementary explanatory diagram of FIG. 5. It is a figure explaining this baking processing. It is a flowchart explaining this baking process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 21 ... Glass grain, 22 ... Resin grain, 30 ... Crushed grain, 35 ... Container without lid, 36 ... Chromium-type substance, 37 ... Glass layer, 40 ... Foamed glass.

Claims (1)

Obtained by cutting a used car, a shredder dust called ASR contain chromium-based material as a starting material, subjected to selection by processing in the starting material, a mix grain of a suitable amount of resin to glass particles In the method for producing foamed glass, the foamed glass is obtained by subjecting the crushed powder to firing treatment.
The firing process includes a plurality of steps, and these steps are:
Filling the crushed powder into a container without a lid;
In order to heat from the upper surface of this container and prevent air from entering and leaving the space where the filled crushed powder is placed and the outside, an upper surface heating step of forming a glass layer on the crushed powder ,
A heating step of obtaining foamed glass by melting the glass particles contained in the glass layer by heating the container as a whole and using the resin particles as a foaming agent. A method for producing foam glass.

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