JPH08224557A - Waste granular material and its production - Google Patents

Abstract

PURPOSE: To obtain a waste granular material having sufficient breaking strength and not eluting a harmful substance. CONSTITUTION: Non-combustible inorg. waste is supplied to a hammer mill type primary crusher 2 from a hopper 1 and primarily crushed so as to obtain a particle size facilitating the treatment of a next process. An aluminum can or the like is preliminarily sorted visually in this case. Subsequently, the crushed waste is classified under vibration by a primary classifier 4 and granules with a predetermined size or more are returned to the crusher while granules with the predetermined particle size or less are passed through a dryer 5, a secondary grinder 6 and a secondary classifier 7 to obtain a granular material with the predetermined particle size. The granular material is sent to a kneader 8 to be kneaded with a solidifying material 9 and an additive material 10, and the kneated matter is granulated by a granulator 11 to obtain a granulated material with a predetermined particle size and predetermined length. This granulated material is aged for a predetermined time in an aging apparatus 16 to be coated with molten asphalt in a coating device 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recycling material and a recycling method for waste containing harmful pollutants, and in particular, incineration ash generated from a waste incineration plant, a power plant, a steelmaking-related furnace, etc. Waste particles such as dust ash solidified into granules and the surface of which is coated with asphalt, and waste particles solidified into asphalt coating on the surface of the waste particles Furthermore, it relates to a method for producing these waste granules.

[0002]

2. Description of the Related Art Wastes such as incinerated ash and electric dust collected when industrial wastes and wastes from urban life are incinerated contain harmful substances such as Cd and Pb. When they are used for landfill or are dumped into the ocean, they must be solidified with cement or the like and treated so that harmful substances are not eluted from them before use. And as a means for solidifying this waste, Japanese Patent Publication No. 58-21551 and Japanese Patent Publication No. 58-5078.
Various proposals have been made in Japanese Patent No. 4, etc.

Of the above-mentioned conventional techniques, the former (Japanese Patent Publication Sho 58
No. 21551) discloses a method for solidifying waste, in which the waste is kneaded with asphalt to be solidified, and the incinerated ash is mixed before kneading with the asphalt. And water are mixed to complete the reaction of the components that react with water.

The latter (Japanese Patent Publication No. 58-56784) discloses a slurry in which waste and asphalt are kneaded in a slurry form, and a powdery or granular material is added to the kneaded mixture to form a funicular shape and then solidified. I am trying to change.

[0005]

The above-mentioned prior art is a technique for solidifying incinerated ash into a relatively large mass for landfilling waste such as incinerated ash or dumping it into the ocean. It was not possible to obtain granular materials suitable for civil engineering materials such as roadbed materials, roadbed materials, and backfill materials. The crushing strength of the solidified product was also low.

It should be noted that neither of the above-mentioned conventional techniques discloses a technique for recycling incinerated ash or the like and a technique for a recycled substance.

The present invention has been made in view of the above points, and is chemically stable, has high crush strength, does not elute harmful substances, and is suitable for civil engineering materials such as roadbed materials, roadbed materials, and backfill materials. It is an object of the present invention to provide a suitable waste granular material and a method for producing the same.

[0008]

In order to achieve the above object, the waste granular material according to the present invention is a granular material obtained by kneading waste, a solidifying material and water and solidifying the mixture. The surface of the granular material is coated with asphalt.

Further, the solidified material is obtained by kneading the granular material consisting of waste material whose surface is coated with asphalt, the solidifying material and water.

Further, in the method for producing the waste granular material, the waste material, the solidifying material and water are kneaded to be solidified into the granular material,
Asphalt is added to the granules and stirred to apply an asphalt coating to the surface of the granules.

Further, asphalt is added to the waste, and the mixture is stirred and cooled. The asphalt coating of this waste, the solidifying material and water are kneaded to solidify.

[0012]

[Operation] According to the present invention, the waste is solidified into a granular material by the solidifying material, and since the surface is coated with asphalt, the waste is doubly confined to prevent the harmful substances inside. Elution is prevented, and the crush strength is also increased. Further, in the case where the waste is first solidified into granules and the granules are asphalt-coated, the water absorption of the granules can be kept low, and the abrasion loss can be reduced. For this reason,
When used as a roadbed material, it is possible to prevent deterioration of the adhesive surface between the roadbed and the surface asphalt pavement after road construction.

[0013]

[Example] An example of using incineration ash of industrial waste as waste will be described with reference to Fig. 1 as an example of the present invention. Incinerator ash from an incinerator (not shown) and other non-combustible inorganic wastes are supplied from a supply hopper 1 to a hammer mill-type primary crusher 2 and have a particle size of about 20 mm or less so that the next process can be easily processed. Primary crushed into particles. Then, iron, steel and other magnetic metals were selected and removed from the primary crushed product by a permanent magnet suspension type magnetic separator 3. The aluminum can and the like were visually selected and removed beforehand. Next, the coarsely crushed product was sieved by a primary classifier 4 including a vibrating screen, and the coarsely crushed product having a particle diameter of 20 mm or more was returned to the coarse crusher 2 by a return conveyor.

The incinerated ash used in this example is sprinkled in the state of being discharged from the furnace for cooling and prevention of scattering, and since it contains about 30% of water as a whole, it is about 700 ° C. Was heated for 10 minutes by a rotary dryer (rotary kiln) 5 using hot air from the hot air generating furnace to evaporate the excess water content to a water content of about 15% by weight. A deodorizer 5A and a dust collector 5B were attached to the heating dryer 5 in order to prevent dust and odor during heating. In addition, there is also an effect of burning organic matter in the ash to make it inorganic during the heating.

Next, the dried coarsely crushed product was crushed by a secondary crusher 6 of a hammer mill system to obtain a sized product having a particle size distribution of about 5.0 mm or less. Next, the sized product is passed through a secondary classifier 7 using a vibrating screen, where the particle size is 5.
The coarsely crushed product having a size of 0 mm or more was returned to the secondary crusher 6 again from the return conveyor.

Each of the above steps is a pretreatment step for incineration ash, whereby the incineration ash becomes a sized product having a predetermined particle size distribution. After rectifying the incinerated ash, the size and shape of the ash can be further adjusted by a classifier, crushed, or mixed with powder with high hardness such as casting dust to adjust the shape and solidify or asphalt coating. The porosity of the incinerated ash is reduced in the inside of the crushed material, and the crush strength can be improved.

Next, the sized product is mixed with a biaxial type forced kneading mixer (K
BHS-60E: manufactured by Koyo Kikai Sangyo Co., Ltd.), and the mixture was kneaded by adding the solidifying material quantitatively supplied from the solidifying material silo 9 and the additive material quantitatively supplied from the additive material silo 10 and water.

The mixing ratio of the solidifying material is 10% with respect to the sized product,
The mixing ratio of the additive was set to 10% with respect to the solidified material, and the ratio of water was set to 15% with respect to the whole (sized particles + solidified material + additive material). Note that this ratio is one example, and the solidifying material is approximately 5 to 5.
40%, and the additive may be approximately 1 to 20% with respect to the solidified material.

The solidifying material firmly bonds the sized products formed from incinerated ash to each other, and a cement binder having a composition of blast furnace cement, Portland cement or alumina cement is used. In the above examples, the solidifying material is mainly composed of Portland cement, and organic acid salts such as sodium ligninsulfonate, sodium stearate and sodium tripolyphosphate, and inorganic auxiliaries such as calcium aluminate, calcium aluminosulfate and calcium silicate. The total amount used was 1 to 3 parts by weight. In the above-mentioned examples, it is desirable that the additive has the effect of breaking out the ettringite crystal for the purpose of early strength development. Depending on the case, an additive material having a higher elution preventing effect such as a heavy metal may be used, and it is naturally possible to add both of them in duplicate. Further, in order to improve the crushing strength, it is also effective to use a hard powder such as casting dust or silica sand as an additive.

The solidifying material and the additive material are commercially available products such as Fujibeton (trade name) as the solidifying material and Zipcal (trade name) as the additive material. The mixing ratio of each commercially available product is On the other hand, 9% of the solidifying material and 1% of the additive material were suitable.

Next, a large number of holes having a diameter of 8 mm and a thickness of 2
The extruded (or tumbling) granulator 11 equipped with a 0 mm screen die was supplied with the kneaded product to granulate, whereby a granulated product having a diameter of approximately 8 mm and a length of 12 mm was obtained.

The extrusion type granulator 11 has a structure as shown in FIG. 3, and when the roller 14 rotates on the upper surface of the screen die 13 in the hopper 12, the granules put in the hopper 12 are sized. The mixture of the substance and the cement is granulated downward through the retainer 13b from the hole 13a of the screen die 13 and discharged. The size of the granulated material 15 at this time is determined by the hole diameter of the screen die 13.

The obtained granulated product was aged at room temperature by a curing device 16 such as a belt conveyor, and the crush strength of the granulated product after 2 hours was measured to be 1.4 kg, and when aged for 6 days, it was 9 It is 0.3 kg and is 1 when aged for 28 days.
It was 1 kg. This means that about 1 week of curing was sufficient. In addition to the extrusion type, a rolling type may be used as the above granulator.

Next, in the coating apparatus 17, 5 to 20% (relative to the weight of the granulated product) of dissolved asphalt is added to the granules and stirred, and after confirming that the surface of the granules is coated with asphalt, The particles are pulled up from the molten asphalt, and the asphalt is cooled and dried so that the particles do not adhere to each other. For example, the granules are arranged in a colander so that they do not overlap each other, passed through molten asphalt, and then cooled and dried. Alternatively, the particles coated with the molten asphalt may be placed in a dry powder such as casting dust and sprinkled with the particles to prevent the particles from adhering to each other.

In the above example, the step after kneading with the solidifying material was the step of granulation → curing → asphalt coating, but as another example, the step after kneading is press molding → curing → crushing. → You may take the step of asphalt coating. Then, by crushing, various shapes can be formed.

When a combination of such coarse particles and fine particles is used for a roadbed material or the like, it is difficult to compact when performing compaction during construction, and compaction is performed densely. As the shape of the granular material, other than the cylindrical shape as in the above-mentioned embodiment, it may be a corrugated shape or a prismatic shape, and when used as a roadbed material, it is desirable that the internal frictional force is large. That is, as the roadbed material is used for the upper layer, the load distribution from the road surface is larger. Therefore, it is desirable that the upper layer roadbed has good aggregate quality, that is, high aggregate strength and low abrasion loss. 45 asphalt coated with granules
%, While the uncoated one was 54%.

The granular material produced in each of the above steps is solidified by mixing the waste material, the solidifying material and the additive material,
And the surface of each of the individual particles is coated with asphalt. Therefore, the individual granules have sufficient crush strength, and the elution of harmful substances from the waste contained in each granule is completely prevented. The crush strength of the asphalt-coated granules was 28 kg after 28 days of curing after coating.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the description of the same steps as those in the above embodiment will be omitted.

The sized product obtained by the secondary classifier 7 is sent to the coating device 18, where it is preheated to about 180 ° C. to be in a molten state and kneaded with the asphalt in the asphalt tank 19 to prepare the sized product. The surface is coated with asphalt. The weight ratio of the sized product to the asphalt was 80:20.

Then, after cooling for 2 hours to a dry state, the kneading machine 8 is used again for the asphalt coating sized product 9
Knead at a ratio of 1% and cement 9%. At this time, depending on the amount of cement, for example, 40% of this amount of cement
Add some water.

In this embodiment, the cooling time after mixing and kneading the sized incineration ash and the asphalt is 1 to 3 hours, and the cement is 10 for the asphalt-coated sized product.
-30%, and the water-cement ratio is 0.3-1.0%.

With respect to the above-mentioned second embodiment, the present inventor carried out the following third, fourth and fifth embodiments. -Third Example Cast dust was mixed with the sized incineration ash in the first example at a weight ratio (the same applies hereinafter) to incineration ash 7 at a ratio of 3. Other than that is the same as the first embodiment.

Fourth Embodiment The cement used in the first embodiment was mixed with cement and casting dust at a ratio of 3 to 7. Other than that is the same as the first embodiment.

Fifth Example (Comparative Example) In the steps of the first example, the sized incineration ash was not subjected to asphalt coating, but the steps of the first example were carried out.

As a result of comparing the 28-day strength of the granules granulated in each of the above examples, the results are shown in Table 1.

[0036]

[Table 1]

In Examples 3 and 4, the crush strength was improved by mixing the casting dust into the sized incineration ash and into the cement, respectively. Casting dust is called calcineer dust that is generated in the recycling process of a foundry, and it is classified by a classifier such as a cyclone so that it cannot be reused. ~ 60
The thing of about μm was used.

[0038]

EFFECTS OF THE INVENTION According to the waste granular material of the present invention, it is chemically stable and has high crushing strength, and each granular material is doubly eluted and sealed by the solidifying material and the asphalt. It is possible to eliminate elution of harmful substances from this waste granular material. The waste granular material obtained in the present invention can be suitably used as a civil engineering material such as a roadbed material, a roadbed material, and a backfill material.

[Brief description of drawings]

FIG. 1 is a system block diagram showing a first embodiment of the present invention.

FIG. 2 is a system block diagram showing a second embodiment of the present invention.

FIG. 3 is a schematic configuration explanatory view showing an example of an extrusion type granulator.

[Explanation of symbols]

 1 ... Hopper 2 ... Primary crusher 3 ... Magnetic separator 4 ... Primary classifier 5 ... Dryer 5A ... Deodorizer 5B ... Dust collector 6 ... Secondary crusher 7 ... Secondary classifier 8 ... Kneader 9 ... Solidifying material silo 10 ... Additive material silo 11 ... Granulator 13 ... Screen die 14 ... Roller 16 ... Curing device 17, 18 ... Coating device 19 ... Asphalt tank.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yohei Hisada 1200 Manda, Hiratsuka-shi, Kanagawa Komatsu Ltd. Research Laboratory

Claims (4)

[Claims] 1. A granular material obtained by kneading a waste material, a solidifying material, and water and solidifying the mixture, wherein the surface of the granular material is coated with asphalt. 2. A waste granular material obtained by kneading a solid material, water, and a granular material composed of a waste material whose surface is coated with asphalt, and solidifying the mixture. 3. The waste, the solidifying material and water are kneaded to solidify the granules, and then asphalt is added to the granules and stirred, and the surface of the granules is coated with asphalt. And a method for producing waste granular material. 4. A method for producing a granular material for waste, which comprises adding asphalt to waste, stirring, cooling, and kneading the asphalt coating of the waste, a solidifying material, and water to solidify.