JPH10217306A - Embedding treatment method of incinerated residual ash - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture base materials utilizable for a building, machinery or the like as a substitute for natural stone by treating incinerated residual ash from urban waste to be harmless, and mix the treated ash into waste plastic to mold solid materials. SOLUTION: A thermoplastic waste plastic (e.g. a PET bottle) is ground, and mixed with incinerated residual ash from urban waste for heating and kneading through an extrusion molder 2. The ash is extruded in bar shapes being covered with plastic. The extruded ash is press-molded through a compression mold 6 having cavities of appropriate shapes such as crushed stone, etc., and molded into solid material. Thus, a molding 8 formed in such a way elutes less lead, chloride ions, etc., including in the ash, so that environmental pollution is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the treatment of incinerated ash such as municipal solid waste, and neutralizes and stabilizes harmful heavy metals and the like remaining in the ash, and converts the ash into solids such as crushed stones. It is intended to be used as a substitute for natural stone as a construction material such as a landfill material, an embankment material, etc., and to be used effectively.

[0002]

[Background Art] The amount of municipal solid waste is continuously increasing every year. The volume of waste is reduced by incineration and the remaining ash is dumped in landfills. Hazardous substances such as heavy metals remain in the incineration ash or electric dust, and are eluted from the landfill over time, adversely affecting the environment. As a result, the effective use of is prevented. It is customary to solidify and embed such harmful substances such as heavy metals with cement so that they do not elute.In this case, deliquescent substances such as calcium chloride and magnesium chloride and sodium chloride are contained in the ash. , Calcium sulfate, potassium chloride, sodium sulfate, etc., it is difficult to mix and solidify these with ordinary cement, and it is necessary to use special cement.

[0003] Further, the incineration ash is solidified with asphalt or plastic. The plaque used in this case is an unsaturated polyester or the like which is in a liquid state at the time of use and is solidified by a curing agent, and a method of pouring the resin so as to cover the ash in the container is adopted, and the whole is coated. And the material is expensive.

In the above-mentioned solidification of plastics, cracks often occur in the solidified body due to hydrogen gas generated from incinerated ash. And
The harmful substances such as the heavy metals are eluted from the cracks, which is not satisfactory as an effect of preventing environmental pollution.

[0005]

Problems to be Solved by the Invention In the present invention,
It is intended to realize the treatment of mainly waste plastic, for example, used PET pottle, and the disposal of incinerated ash and dust ash generated from municipal solid waste in an integrated manner. That is,
The incineration ash is mixed with the plastic in the heated and molten state,
The decomposition product of the molten plastic and the heavy metals in the ash are reacted and neutralized, and further, each particle of the ash is wrapped in plastic and formed into a crushed stone shape to be solidified. The solid material can be effectively used as a substitute for natural stone used as a base material for buildings and machines, or as a ground improvement material for landfills.

[0006]

[Means for Solving the Problems] In a cylinder of a plastic extruder, kneaded plastics heated and melted and incineration residual ash such as the above-mentioned municipal solid waste are extruded together with the plastics from a nozzle at the tip of the cylinder, and this is molded into a mold. It is molded into an appropriate shape using and cooled and solidified.
This is a combination of extrusion molding and compression molding.

In addition, as a plastic for producing a solid material filled with incineration ash, it is desirable to use thermoplastic polyethylene terephthalate, polyamide, polycarbonate or the like having a low melt viscosity. The surface of the particles is coated with resin,
Further, it is desirable to have a component that neutralizes the alkaline component in the ash by the decomposition gas of the resin.

[0008]

Since the incinerated ash is coated with plastic in the unit of particles, even if the solid material is cracked and broken, the pollutant is not eluted, so that the environment is not adversely affected.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A method for embedding incineration residual ash according to the present invention will be described with reference to the drawings. FIG. 1 shows an apparatus for filling incineration ash into a plastic material and solidifying it. That is, a die 3 for extruding and molding a molten resin into a cylindrical shape is attached to a nose portion of a plastic extruder 2 having one or two hoppers, and subsequently has an inner diameter substantially equal to the inner diameter of the die 3, and Then, a cooling die 4 having a channel for circulating cooling water is mounted. Further, a reheating die 5 provided with a heater 5a continuously connected to the cooling die is connected to the tip end thereof, and one or several pairs of compression moldings having a cavity 6a for forming a crushed stone at the end thereof. The mold 6 is provided via a suitable mold closing and opening device 7 such as a press, a roller, or a caterpillar.

In the final step of the compression molding apparatus, a plurality of cavities are formed on the surface of a pair of rollers. The rods are sequentially closed and opened with the rotation of the caterpillar. The purpose of these is to continuously introduce and extrude the extruded rod into the cavity. In addition to this, the rod extruded from the extrusion device is cut to an appropriate length,
This may be charged into a mold cavity attached to another compression molding machine (press) to perform molding.

As described above, as a material to be put into the hopper 2a of the extruder 2, a thermoplastic resin such as PET, polyamide, or polycarbonate having a low melt viscosity is selected as described above. If so, mainly plastic waste will be targeted. When a discarded PET bottle is used, it is necessary to grind the bottle into flakes in advance using a grinder, and to cut the PET fiber into a length of 2 to 3 cm in the case of PET fiber. This facilitates biting from the hopper of the molding machine into the cylinder.

A predetermined amount of incinerated ash is added to the pulverized plastic material and mixed. In this case, although a plastic and incineration ash are respectively transferred to a hopper of an extruder at a fixed amount, dropped into a cylinder, and cut into the cylinder, a molded product filled with a fixed amount is obtained, but other mixing methods may be used. The filling amount of incinerated ash with respect to the plastic material can be formed in the range of 5 to 50% by weight, but in order to use the formed solid as a substitute for crushed stone, the filling amount of incinerated ash is set to 30% by weight. It is desirable to stop below.

[0013]

Embodiment One embodiment will be described. For the plastic material, used PET pots were pulverized by a pulverizer so that the surface area became about 1.5 square cm or less. Two types were used: one obtained by drying this material in a hot air circulating furnace at 180 ° C. for 4 hours, and the other type obtained by drying a PET material for spinning at 180 ° C. for 4 hours in the same manner as described above.

As the incineration ash, ash remaining in the furnace of a municipal waste incineration plant of a local government was used. This incinerated ash has a pH of 9.5, and contained harmful components as shown in Table 1.
It contained lead and chloride ions.

[0015]

[Table 1]

Such incinerated ash was sufficiently dried and undried (water content: 9% by weight), and the PET resin was filled at 10, 20, and 30% by weight (Table 2). Filling of resin with incinerated ash is based on a method in which PET material is fed into the main hopper by a feeder and at the same time incinerated ash is fed by another feeder. Was.

[0017]

[Table 2]

[0018] The resin and the ash are mixed in a cylinder using a dalmage type extruder 2 having a cylinder inner diameter of 40 mm at a temperature of 240 ° C. to 280 ° C. and a screw of 50 revolutions per minute. The mixture was melted and kneaded in the inside, formed into a rod 6 having a diameter of about 30 mm by a die 3, and extruded. Next, the liquid having a temperature of 30 ° C. or less is circulated and cooled, and the inner diameter is 30 mm and 50 to 100 c.
The rod is passed through the inside diameter of the die 4 to cool and solidify from the surface of the rod-shaped body, and further passed through the inside diameter of the reheating die 5 heated to 150 to 200 ° C. Heat was applied to obtain a softened state required for compression molding.

The flexible rod 8 extruded from the reheating die in this way was introduced into a pair of compression molding dies for forming a crushed stone, and compression molding was performed. An example of the shape of the molded article is shown in FIG. 2 (a square body of about 5 × 4 × 2 cm), but it is a matter of course that the present invention is not limited to this. The incinerated ash-filled molded article formed by the above method was notified by the Environment Agency
Table 3 shows the results of the test according to No. 3. In addition, the test method is as follows.
The divalent chromium was measured by diphenylcarbagide absorption spectrophotometry according to JIS K010265, and the chloride ion was measured by silver nitrate titration.

[0020]

[Table 3]

The reclaimed polyamide resin is filled with 20% by weight of incinerated ash, and the cylinder 2b of an extruder is used.
Was set to 280 ° C. The polyamide at this temperature had a very low melt viscosity and was therefore mixed well with the incineration ash. Then, the surface of the rod 8 is heated by the reheating die 5 or a flame to a temperature higher than the melting temperature of the resin to form a resin layer on the surface of the molded article, which is covered with ash. Diminished.

Extrusion molding was performed by filling 20% by weight of incineration ash with respect to 100 parts of polycarbonate, and a molded product was produced. In this molding, it is necessary to sufficiently dry the molding material and the incineration ash to be filled, as in the ordinary molding. The resin is decomposed by raising the temperature of the cylinder 2b to a slightly warmer temperature than usual, and the gas generated at that time neutralizes the heavy metals in the incineration ash by reacting. Elution tended to decrease.

[0023]

As can be seen from Table 3, the incineration ash dried with respect to the PET resin was filled with 10% by weight. 1,
No. Sample No. 5 showed very little elution of lead and also reduced chloride ions. It is thought that a molded product with almost the same embedding effect as a dry ash-filled product can be obtained by molding using an extruder with an air vent in the cylinder even when ash is filled with undried incineration ash. Can be

The crushed stone (residual ash 20
(% By weight or less) had high strength and high impact resistance, and could be used as a basic material for construction, civil engineering facilities and machine tools, and as a paving stone for gardens.

[Brief description of the drawings]

FIG. 1 is a side view showing the outline of an extrusion molding apparatus for embedding incineration ash according to the present invention.

FIG. 2 is a perspective view showing an example of a molded product embedded with incinerated ash according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 molding apparatus 2 extrusion molding machine 3 extrusion die 4 cooling die 5 reheating die 6 compression molding die 7 press mounting plate 8 rod-shaped molded product

Claims (2)

[Claims] 1. Filling of plastics with residual ash generated by incineration of municipal waste, etc., melting and kneading in a heating cylinder, extrusion, and shaping into solids such as crushed stones. Processing method. 2. The method according to claim 1, wherein the plastic is a thermoplastic such as polyethylene terephthalate, polyamide or polycarbonate.