JP3086200B2 - Solidification and stabilization of molten fly ash - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to molten fly ash generated during melting treatment of wastes, waste incineration residues, etc., by adding crushed slag obtained by pulverizing molten slag and, if necessary, additives such as lime. In addition, after kneading with water, press molding if necessary, curing and solidification of molten fly ash to be solidified and stabilized.
It relates to the stabilization process how. Wastes and waste incineration residues include general wastes, residues from incineration treatment, for example, garbage, garbage incineration residues, human waste incineration residues, etc., and industrial wastes, residues from incineration treatment,
For example, sludge such as sewage sludge, sludge incineration residue such as sewage sludge, shredder dust, shredder dust incineration residue, waste plastic, waste plastic incineration residue, steel dust, coal ash and the like are used. The treated product obtained by the method of the present invention is disposed of in landfill or is effectively used for civil engineering materials and the like.

[0002]

2. Description of the Related Art Conventionally, as a method for stabilizing molten fly ash, a method of kneading with a chemical and disposing of the treated material as landfill waste as a controlled waste is disclosed, for example, in Japanese Patent Application Laid-Open No. 7-290026. Then, a sulfuric acid band is added to the molten fly ash obtained by the melting treatment, and then a heavy metal fixing agent (liquid chelating agent) is added to convert the heavy metal into a chemically stable heavy metal chelate compound. There is known a method of stabilizing molten fly ash by preventing elution of heavy metals.

Japanese Patent Application Laid-Open No. Hei 9-110146 discloses that a Blaine value of 40 parts by weight for molten fly ash is 40 parts.
Fine granulated blast furnace slag powder of 00 cm ² / g or more
A method is described in which 0 parts by weight, if necessary, slaked lime is added and kneaded with water, followed by steam curing at 60 to 180 ° C. In addition, conventionally, a yamamoto reduction method in which an additive is added to molten fly ash to recover and use valuable metals has been known.

[0004]

The above-mentioned JP-A-7-29
In the method described in Japanese Patent Publication No. 0026, since the processed material is not solidified, the strength is small and the handling property is poor. Also,
It is necessary to adjust the addition amount of the chemical depending on the composition of the molten fly ash and the content of the harmful heavy metal, and the operation is complicated. In addition, there is a problem in that the soil environmental standards are not satisfied even when the criteria for landfill are satisfied in the elution of harmful heavy metals.

In the method described in Japanese Patent Application Laid-Open No. Hei 9-100146, since blast furnace slag powder not related to the melting furnace is used, a large amount of additive material (blast furnace slag) is supplied from outside.
Must be transported and added, leading to increased costs. In addition, there is a problem that the processed product does not become a high-strength solid. Further, in this publication, there is no description of a technical idea that one of the features of the present invention is to granulate while kneading, or to form a kneaded product under pressure and then perform curing treatment in a range of room temperature to 55 ° C. It has not been. In the Yamamoto reduction method, new waste is generated in the process of concentrating valuable metals, and it does not become a self-contained system, that is, a system that does not generate new waste, and requires a large amount of additives. However, there is a problem that a large amount of wastewater is generated.

The present invention has been made in view of the above points, and an object of the present invention is to add crushed slag prepared by pulverizing molten slag to molten fly ash, knead with water, and then add as required. It is a so-called self-contained system that does not generate new waste by pressing and then curing at room temperature to 55 ° C, so that external additives are unnecessary or minimized, and the composition differs. Applicable to various types of molten fly ash, it satisfies not only the landfill criteria but also the soil environmental standards for elution of harmful heavy metals. there is to provide a solidifying and stabilization how the molten fly ash can be total amount available.

[0007]

In order to achieve the above object, a method for solidifying and stabilizing molten fly ash according to the present invention is directed to a method for treating 10 parts by weight of molten fly ash captured from exhaust gas from a melting furnace. Then, the slag melt-processed in the melting furnace is pulverized, 10 to 200 parts by weight of a pulverized slag having a Blaine specific surface area of 2000 cm ² / g or more is added, and the mixture is granulated while being kneaded with water. Curing treatment in the range of room temperature to 55 ° C ,
Then, curing treatment is performed in a saturated steam atmosphere at 60 to 98 ° C. (see FIGS. 1 and 7 ). The addition amount of the kneading water is 2 to 5 parts by weight, preferably 2.5 to 4 parts by weight based on 10 parts by weight of the mixture of the molten fly ash and the pulverized slag .

Further, the method of the present invention, the molten fly ash 10 parts by weight of the captured from the exhaust gas from the melting furnace, Blaine specific surface area of 2000 cm ² / g or more by grinding a molten processed slag at this melting furnace 10 to 200 crushed slag
After adding the parts by weight and kneading with water, the kneaded product or the kneaded granulated product is subjected to pressure molding, and then the molded product is subjected to curing treatment in a range of room temperature to 55 ° C., and then saturated steam of 60 to 98 ° C. It is characterized in that it is cured under an atmosphere (see FIGS. 2 and 7).

In these methods, Ca in molten fly ash
When the O content is less than 10 wt%, at least one additive selected from the group consisting of quick lime, slaked lime, limestone, gypsum, caustic soda and calcium chloride is added to 10 parts by weight of molten fly ash. It is preferable to add 0.01 to 10 parts by weight (see FIGS. 3 and 4). Further, after drying the molten slag, it was pulverized to a Blaine specific surface area of 2000 cm.
² / g or more of powder slag is preferable (FIG. 1 to FIG. 1).
(See FIG. 4). As the kneading water, industrial water or seawater is used. When seawater is used, there is an advantage that the strength of the processed material is increased. Further, the final processed product may be crushed into a granular material having a particle size distribution of 0.05 to 40 mm (see FIGS. 8 and 9) .

[0010] In the method of the present invention, the ground slag prepared by pulverizing molten slag (water-cooled slag) has a Blaine specific surface area of 2,000 to 10,000 cm ² / g. In addition, the Blaine specific surface area is a value measured using a Blaine air permeation apparatus described in JIS R 5201 (physical test method for cement) and is an index indicating fineness of particles. The specific surface area of the crushed slag is 2000cm
^When it is less than ² / g, the hydration reactivity is not good, and the compressive strength of the obtained processed product (solidified product) is not sufficient, and the possibility of elution of heavy metals occurs. As the Blaine specific surface area increases, the hydration reactivity increases, and the compressive strength of the solidified body increases, but it is economically disadvantageous. Therefore, although the upper limit of the brane specific surface area is not limited, it is preferable to set the upper limit to 10,000 cm ² / g in practical use. The lower limit is preferably 2500 cm ² / g.

The amount of pulverized slag added is 10 to 200 parts by weight, preferably 20 to 10 parts by weight, per 10 parts by weight of molten fly ash.
0 parts by weight. If the lower limit is less than the lower limit, if the harmful heavy metal content in the molten fly ash is large, or if the content of NaCl or the like is large, there is a disadvantage that the harmful heavy metal is not sufficiently stabilized or is not sufficiently solidified. If the upper limit is exceeded, if the amount of molten fly ash generated with respect to the amount of slag increases, there is a disadvantage that the amount of slag for solidifying and stabilizing the molten fly ash becomes insufficient or the amount of slag used decreases. As the kneading water, water at normal temperature or warm water at 30 to 60 ° C is used. When warm water is used, there is an advantage that the strength and stability of the processed product are improved. Further, there is an advantage that stable quality of the processed material can be ensured even in winter and in cold regions.

Further, the kneaded granulated product and the press-formed product are kept at room temperature to 5 ° C.
When the curing treatment is performed at 5 ° C., the curing treatment is preferably performed for 24 hours or more. After curing at room temperature to 55 ° C. and then performing saturated steam treatment as in the present invention , room temperature to 55 ° C.
The curing treatment at ℃ is preferably 24 hours or more, but may be performed for 5 to 24 hours.
It is preferable to set it to 24 hours. The upper limit of 55 ° C. in “normal temperature to 55 ° C.” is a value in consideration of a case where a kneaded material or a molded article having low strength does not crack due to expansion due to a rapid hydration reaction. The amount of additives such as CaO, Ca (OH) ₂ limestone, gypsum, NaOH, and CaCl ₂ is 0.01 to 10 parts by weight, preferably 0.02 to 5 parts by weight per 10 parts by weight of molten fly ash. It is. For example, when two types of additives are added, the total amount added is 0.03 to
Make up to 10 parts by weight. In order to perform the melting furnace exhaust gas treatment, lime such as slaked lime or quick lime is added to the exhaust gas, and unreacted lime is included in the molten fly ash, so this lime is used. If the lime content in the molten fly ash is 10% by weight or more, there is no need to add additives,
Only when the aO content is less than 10 wt%, additives are added for increasing the strength and stabilizing the treated product.

In the present invention, since the molten fly ash is completely solidified and stabilized by semi-dry treatment without generating exhaust gas and wastewater, a self-contained system (without generating new waste) can be provided. it can. In addition, since crushed slag (having hydraulic properties) is used by crushing molten slag (water-cooled slag) from the melting furnace that generated molten fly ash, there is no need to transport and introduce slag from outside the melting furnace, Other additives may also be unnecessary or minimized. Further, the addition of molten fly ash the same amount or more grinding slag and additives added lime, etc., room temperature curing process, and further, since to produce more hydrate at steam curing process, molten fly The harmful heavy metal can be fixed against the change in the composition of the ash and the change in the content of the harmful heavy metal, and the strength with good handling properties can be secured. That is, it can be applied to various types of molten fly ash (having different compositions). Further, in the room temperature curing treatment, harmful heavy metals are fixed by the hydration reaction products generated by many pulverized slags, and the landfill determination standard can be satisfied. Further, the steam curing process line Ukoto, the hydration reaction is more advanced, and there is no free lime, toxic heavy metals can be more secured, it is possible to satisfy the environmental quality standards for soil. That is, regarding the elution of harmful heavy metals, not only the landfill criteria but also the soil environmental standards can be satisfied.

Further, by increasing the amount of pulverized slag, after room temperature curing process, and the strength after steam curing process is improved. Therefore, the strength required for handling and the strength required for effective use are within the range of molten slag discharge for molten fly ash (usually, 5 wt% of molten fly ash from the melting furnace,
95% by weight of molten slag is discharged. ), No external slag is required, or no increase is required.
Thus, the strength of the processed material is high and the handling properties are good, and the molten fly ash can be solidified only by the molten slag from the melting furnace. Further, since the entire amount of the processed material can be subjected to the solidification / stabilization treatment, the entire amount of the processed material can be effectively used. Further, by performing the steam curing process, it is possible to satisfy the criteria and is the soil environment standard for effective use. Further, when crushing is performed, the modified CBR becomes 80% or more, and it can be used for civil engineering materials such as roadbed materials and backfill materials. Here, modification C
BR is an index indicating the strength of a granular material used as a civil engineering material such as a roadbed material . The larger the value, the better the strength, and the JIS A 1211 (Carrying ratio of subgrade soil (CBR))
According to the method described in (Test Method), each layer 92 is divided into three layers.
It refers to a water immersion CBR corresponding to a required degree of compaction with respect to the maximum dry density when compacted multiple times.

Since the above-mentioned crushed molten slag has hydraulic properties, it can be used as a substitute for cement. For example, a kneaded material with water becomes high in strength by a stimulant such as lime, and can be effectively used as a building material, a block, a ground improvement material, and the like.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments and can be implemented with appropriate modifications. FIG. 1 shows an apparatus for implementing a method for solidifying and stabilizing molten fly ash according to a first embodiment of the present invention. The apparatus shown in FIG. 1 is an ash measuring / supplying means for measuring and supplying the molten fly ash stored in the molten fly ash hopper 10 to the kneading machine 12, for example, an ash measuring machine 14, an ash supply line 16 and a supplying machine 18 Ash supply means comprising:
Slag measuring and supplying means for measuring and supplying the crushed slag from the crusher 22 stored in the crusher 22 to the kneader 12, for example, a slag weigher 24 and a slag supply line 26, and a kneader for mixing water (including hot water). Water supply means for supplying, for example,
A water supply line 30 having a water supply pump 28, a kneader 12 for kneading the molten fly ash and the pulverized slag with water, and a room temperature for curing the kneaded granules at room temperature or at a temperature near room temperature (room temperature to 55 ° C). A curing processing unit, for example, a room temperature curing processing chamber 32 is provided. 34 is a water tank, 36 and 38 are conveyors, and 40 is a processed material.

Objects to be treated, such as waste and waste incineration residues, are melted in a melting furnace 42, and slaked lime, quicklime or limestone powder is added to the melting furnace exhaust gas and introduced into a dust collector 44 such as a bag filter. Exhaust gas treatment (desalting, desulfurization) is performed, and molten fly ash containing unreacted lime is captured and stored in the molten fly ash hopper 10 by a transport means such as a conveyor or an airflow transport pipe. On the other hand, the molten slag from the melting furnace 42 is put into a water-cooled tank (not shown), turned into water-cooled slag, introduced into a dryer 46 and dried, and then pulverized by a pulverizer (dry pulverizer) 22. The slag becomes powder slag (in this case, powder slag) and is stored in the slag hopper 20 by a transporting means such as a conveyor 48.

In the apparatus configured as described above, when the content of CaO in the molten fly ash is 10% by weight or more, the molten fly ash is weighed by the ash meter 14, and an additive such as lime is added. Instead, it is fed into the kneader 12 via the ash supply line 16 and the ash supply machine 18. On the other hand, the pulverized slag is weighed by a slag measuring machine 24 and is charged into the kneader 12 via a slag supply line 26. Further, water (including hot water) required for kneading and granulation is supplied to the kneading machine 12, and is agitated and granulated into granules of about 40 mm or less. The granular material is left to stand at room temperature to 55 ° C. for one day or more in a room temperature curing treatment chamber 32 to be solidified and stabilized. Treated 40, in some cases it is landfill, after cold curing, 60 and 98
It is steam cured for 5 to 24 hours under a saturated steam atmosphere at ℃, resulting in a treated product with higher strength and excellent stability.
(Not shown, see FIG. 7 described later) .

If the addition of hot water is applied to winter or cold regions where the ambient temperature is low, a more stable processed product can be obtained throughout the year. Further, by adding hot water, the strength and stability of the processed product can be further improved. Dryer 46
Drum dryers with steam, stirring dryers,
A band dryer using hot air, a fluidized-bed dryer, a rotary dryer, or the like can be used. As the crusher 22, a fine crusher such as a vibration mill, a ball mill, and a roller mill is suitable. As the kneader 12, a kneader capable of stirring and granulating, such as a backflow high-speed kneader (Eirich mixer), a Henschel mixer, or a horizontal axis rotary kneader, can be used.

[0020] Figure 2 is melted by the second embodiment of the present invention
The apparatus which performs the solidification and stabilization processing method of fly ash is shown. In the present embodiment, the kneaded material or the kneaded granulated material from the kneading machine 12 is pressure-formed into a predetermined shape (for example, an almond shape, a column shape, a block shape, or the like) by the pressure molding machine 50, and then,
The pressure-formed product is left in a room temperature curing treatment chamber 32 at room temperature to 55 ° C. for one day or more to solidify and stabilize. Examples of the kneader 12 include, in addition to models capable of stirring and granulating, such as a backflow type high-speed kneader (Erich mixer), a Henschel mixer, a horizontal axis kneader, and a vibrating kneader (vibro mixer), a vertical axis high-speed kneader. A kneader (such as a pin mixer) is suitable. As the pressure molding machine 50, a high-pressure type such as a briquette machine, an extrusion type, a low-pressure type such as a block machine is suitable. Other configurations and operations are the same as those of the first embodiment shown in FIG.

[0021] Figure 3 is melted according to a third embodiment of the present invention
The apparatus which performs the solidification and stabilization processing method of fly ash is shown. The present embodiment measures at least one additive selected from the group consisting of quicklime, slaked lime, limestone, gypsum, caustic soda, and calcium chloride to the kneader 12 (in FIG. One) additive metering
Supply means, for example, an additive storage tank 5 for storing the additive A
2. Measuring machine 54 for additive A, supply line 5 for additive A
6. Additive storage tank 58 for additive B, measuring machine 6 for additive B
0, the supply line 62 for the additive B is connected via the feeder 18, and when the CaO content in the molten fly ash is less than 10% by weight, at least 10 Any of them is added in an amount of 0.01 to 10 parts by weight. As described above, by replenishing the additive, the treated product can be further strengthened and stabilized. The additive supply system may be one system or three or more systems. Other configurations and operations are the same as those of the first embodiment shown in FIG.

[0022] Figure 4 is melted according to a fourth embodiment of the present invention
The apparatus which performs the solidification and stabilization processing method of fly ash is shown. In the present embodiment, the kneaded material or the kneaded granulated material from the kneading machine 12 is pressure-formed into a predetermined shape (for example, an almond shape, a column shape, a block shape, or the like) by the pressure molding machine 50, and then,
The pressure-formed product is left in a room temperature curing treatment chamber 32 at room temperature to 55 ° C. for one day or more to solidify and stabilize. Examples of the kneader 12 include, in addition to models capable of stirring and granulating, such as a backflow type high-speed kneader (Erich mixer), a Henschel mixer, a horizontal axis kneader, and a vibrating kneader (vibro mixer), a vertical axis high-speed kneader. A kneader (such as a pin mixer) is suitable. As the pressure molding machine 50, a high-pressure type such as a briquette machine, an extrusion type, a low-pressure type such as a block machine is suitable. Other configurations and operations are the same as those of the third embodiment shown in FIG.

[0023] Figure 5 is melted according to a fifth embodiment of the present invention
The apparatus which performs the solidification and stabilization processing method of fly ash is shown. In this embodiment, the slag dryer 46 in the first embodiment shown in FIG. 1 is omitted, and the water-cooled slag from the melting furnace 42 is wet-pulverized by the wet pulverizer 23 without drying, so that the pulverized slag slurry is obtained. The slag slurry is stored in the slag slurry tank 21 via the slurry conveying means 49. As the wet crusher 23, a vibration mill, a ball mill or the like is suitable.
Other configurations and operations are the same as those of the first embodiment shown in FIG. Further, in the second embodiment shown in FIG. 2, it is of course possible to omit the dryer 46 and wet-pulverize the water-cooled slag as it is.

[0024] Figure 6 is melted according to the sixth embodiment of the present invention
The apparatus which performs the solidification and stabilization processing method of fly ash is shown. In this embodiment, the slag dryer 46 in the fourth embodiment shown in FIG. 4 is omitted, and the water-cooled slag from the melting furnace 42 is wet-pulverized by the wet pulverizer 23 without drying, so that the pulverized slag slurry is obtained. The slag slurry is stored in the slag slurry tank 21 via the slurry conveying means 49. As the wet crusher 23, a vibration mill, a ball mill or the like is suitable.
Other configurations and operations are the same as those of the fourth embodiment shown in FIG. Further, in the third embodiment shown in FIG. 3, it is of course possible to omit the dryer 46 and wet-pulverize the water-cooled slag as it is.

[0025] placed in the first to sixth embodiment of FIG. 7 is the invention
With a room temperature curing section and a steam curing section.
An example is shown. In the present embodiment, a room temperature curing unit, for example, a downstream unit of a room temperature curing unit 64 is provided with a steam curing unit, for example, a room temperature curing unit 66 for performing a curing process in a saturated steam atmosphere. In FIG. 7, the kneaded material, the kneaded granulated material, or the press-formed product by the press-forming machine (not shown) from the kneader 12 in the first to sixth embodiments is conveyed by conveying means such as a conveyor 68. It is supplied to the room temperature curing treatment machine 64, and is cured for 5 to 24 hours or 24 hours or more in the range of room temperature to 55 ° C., and then supplied to the steam curing treatment machine 66 by a supply device 70 such as a rotary supply device. The curing treatment is performed for 5 to 24 hours in a saturated steam atmosphere at 60 to 98 ° C. 72 is a discharger such as a rotary discharger, 73 is a conveying means such as a conveyor, and 41 is a processed material. To perform steam curing after normal temperature curing
Thus , a processed material 41 having higher strength and excellent stability can be obtained. Room temperature curing machine 64, steam curing machine 6
As 6, a type in which curing treatment is performed while sequentially moving downward while being transported by a conveyor, a type in which curing treatment is performed while sequentially moving downward while stirring with a stirring blade joined to the vertical axis, and the like can be applied. . Other configurations and operations are
This is the same as in the first to sixth embodiments.

FIG. 8 shows the melting according to the seventh embodiment of the present invention.
The main part of the apparatus which implements the solidification and stabilization processing method of fly ash is shown. In the present embodiment, a crusher 74 for crushing the final processed product in the first to sixth embodiments is provided. That is, the final processed product is formed into an irregular shaped granular material of 40 mm or less (0.05 to 40 mm) by the crusher 74. 76
Is a conveying means such as a conveyor, and 43 is a crushed product. As the crusher 74, an impact type such as a hammer mill or an impeller breaker is suitable. By the crushing process, the modified CBR of the crushed product 43 becomes 80% or more, and the roadbed material,
It can be effectively used as civil engineering material such as backfill material.
Other configurations and operations are the same as those in the first to sixth embodiments.

FIG. 9 shows the melting according to the eighth embodiment of the present invention.
The main part of the apparatus which performs the solidification and stabilization processing method of fly ash is shown. In this embodiment, the final product in the first to sixth embodiments is divided into two by the primary crusher 75 and the secondary crusher 78.
It is designed to be broken into steps. That is, the particle size distribution of the crushed material 45 after crushing is shown in FIG.
More strict than in the case of 7 forms (broader particle size distribution width)
For this purpose, the primary crusher 75, the sieving machine 80, the distributor 82 for dividing the crushed primary crushed material into a predetermined ratio, and the secondary crusher 78 for further crushing the distributed primary crushed material are combined. The top of the sieve 80 is returned to the primary crusher 75 and crushed again. 84 is a conveying means such as a conveyor. Other configurations and operations are the first to first embodiments.
This is the same as in the case of the six modes.

[0028]

EXAMPLES Examples , test examples and comparative examples are shown below.
The features of the present invention will be further clarified. Test Example 1 Melt fly ash A (Ca 10.6 wt.
%) 75 parts by weight of water-cooled slag discharged at the same time as the molten fly ash is dried and then crushed by a vibration mill to produce a slag powder (Brain specific surface area: 3000 cm).
² / g) 200 parts by weight, and further added 40 ° C. hot water 7
0 parts by weight and kneading with a backflow high-speed kneader.
Granules having a size of 0 mm or less were subjected to a curing treatment at room temperature (25 ° C.) for 48 hours. The crushing strength of the treated product was 5 kg (10 mm particles), and the amount of harmful heavy metals released by the dissolution test based on the notification of the Environment Agency Notification No. 13 was as follows, satisfying the landfill judgment criteria. T · Hg 0.005 ppm or less Cd 0.01 ppm or less Pb 0.05 ppm Cr ⁶⁺ 0.05 ppm or less As 0.01 ppm or less Se 0.01 ppm or less The landfill judgment criteria are as follows. T · Hg 0.005 ppm or less Cd 0.3 ppm or less Pb 0.3 ppm or less Cr ⁶⁺ 1.5 ppm or less As 0.3 ppm or less Se 0.3 ppm or less

[0029]

[Table 1]

Test Example 2 Melt fly ash B (Ca 1.94 wt.
%) With respect to 100 parts by weight, water-cooled slag discharged at the same time as molten fly ash is wet-pulverized with a vibration mill to produce a slag powder (Brain specific surface area: 3000 cm ² / g)
) Add 250 parts by weight (60 parts by weight of water) and 15 parts by weight of slaked lime, and knead with a backflow high-speed kneader to 40 mm.
The following granules were cured at room temperature (25 ° C.) for 48 hours. The crushing strength of the treated product was 4 kg (10 mm particles), and the leaching amount of harmful heavy metals in the leaching test based on the Environment Agency Notification No. 13 was as follows, satisfying the landfill judgment criteria. T · Hg 0.005 ppm or less Cd 0.01 ppm or less Pb 0.04 ppm Cr ⁶⁺ 0.05 ppm or less As 0.01 ppm or less Se 0.01 ppm or less

Test Example 3 A slag powder (blaine specific surface area) produced by wet-pulverizing a water-cooled slag discharged simultaneously with molten fly ash with a ball mill to 75 parts by weight of molten fly ash A shown in Table 1
3000 cm ² / g) 250 parts by weight (60 parts by weight of water) and 4 parts by weight of caustic soda are added, and the mixture is kneaded with a horizontal-axis rotary kneader to form granules having a diameter of 40 mm or less.
For 48 hours. The crush strength of the treated product is 7
kg (10 mm particles), and the elution amount of harmful heavy metals in an elution test based on Notification No. 13 of the Environment Agency was as follows, and satisfied the landfill judgment criteria. T / Hg 0.005 ppm or less Cd 0.01 ppm or less Pb 0.06 ppm Cr ⁶⁺ 0.05 ppm or less As 0.01 ppm or less Se 0.01 ppm or less

Test Example 4 Water-cooled slag discharged simultaneously with molten fly ash was wet pulverized with a ball mill with respect to 60 parts by weight of molten fly ash B shown in Table 1 to obtain a slag powder (blaine specific surface area:
3000 cm ² / g) 250 parts by weight (60 parts by weight of water) and 10 parts by weight of slaked lime are added, and the mixture is kneaded with a backflow high-speed kneader, and further molded with a size of 20φ × 20 to 50 mm by an extruder. After that, a curing treatment was performed at room temperature (25 ° C.) for 48 hours. The crushing strength of the treated product was 10 kg (20 mm particles), and the amount of harmful heavy metals dissolved by the dissolution test based on the Environment Agency Notification No. 13 was as follows, satisfying the landfill criteria. T / Hg 0.005 ppm or less Cd 0.01 ppm or less Pb 0.04 ppm Cr ⁶⁺ 0.05 ppm or less As 0.01 ppm or less Se 0.01 ppm or less

[0033] was carried out 10 hours curing treatment with saturated steam under the process was 95 ° C. according to Example 1 Test Example 1. The crushing strength of the treated material is 20 kg (10
mm particles), and the amount of harmful substances eluted by an elution test based on the Environment Agency Notification No. 46 satisfied the soil environmental standard.

Example 2 A water-cooled slag discharged simultaneously with molten fly ash was wet-pulverized with a vibration mill with respect to 75 parts by weight of molten fly ash B shown in Table 1 to produce a slag powder (blaine specific surface area: 3).
000 cm ² / g) 250 parts by weight (60 parts by weight of water) and 15 parts by weight of slaked lime are added and kneaded by a vibrating kneader. Further, a molded article having a size of 300 □ × 100 mmH is formed by a low-pressure vibration molding machine. After curing for 10 hours at room temperature (25 ° C.), curing was performed for 10 hours under 95 ° C. saturated steam, and a granular material equivalent to crusher run C-40 was obtained with an impact crusher. The modified CBR of the granular material was 110%, and the elution amount of harmful heavy metals in an elution test based on the notification of the Environment Agency Notification No. 46 satisfied the soil environmental standard. The crusher run C-40 is a granular material after being divided by a crusher (crusher), and is a material having a maximum particle size of 40 mm and used for a roadbed material or the like.

Example 3 With respect to 75 parts by weight of molten fly ash A shown in Table 1, water-cooled slag discharged at the same time as molten fly ash was dried by a stirring dryer.
200 parts by weight of a slag powder (blaine specific surface area: 3000 cm ² / g) produced by pulverizing with a vibration mill was added, and further, 0.7 parts by weight of caustic soda was added at 40 ° C.
70 parts by weight of hot water were added, and the mixture was kneaded with a backflow high-speed kneader to form granules having a size of 40 mm or less. After curing at 40 ° C for 10 hours, curing was performed at 95 ° C under saturated steam for 10 hours. A granular material equivalent to crusher run C-30 was obtained with a crusher. The modified CBR of the granular material was 97%, and the elution amount of harmful heavy metals in the elution test based on the notification of the Environment Agency Notification No. 46 satisfied the soil environmental standard. The crusher run C-30 is a granular material after being divided by a crusher, and is a material having a maximum particle size of 30 mm and used for a roadbed material or the like. Further, in order to carry out the curing treatment at 40 ° C. for 10 hours, the mixture was placed in a closed chamber, and a small amount of steam was injected to maintain the temperature at 40 ° C.

Comparative Example 1 To 100 parts by weight of molten fly ash B shown in Table 1, 30 parts by weight of a sulfuric acid band and 2 parts by weight of a chelate liquid (carbamic acid-based sulfur compound) were added, and 30 parts by weight of water at 25 ° C. In addition, the mixture is kneaded with a twin-screw paddle mixer at room temperature (25 ° C).
Curing treatment was performed for 8 hours. The treated product was not solidified, and the amount of harmful heavy metals eluted by an elution test based on the Environment Agency Notification No. 13 was as follows, and satisfied the landfill judgment criteria.
On the other hand, the elution amount of harmful substances in the elution test based on the Environment Agency Notification No. 46 exceeded the soil environmental standard. T · Hg 0.005 ppm or less Cd 0.01 ppm or less Pb 0.12 ppm Cr ⁶⁺ 0.05 ppm or less As 0.01 ppm or less Se 0.01 ppm or less

Comparative Example 2 To 100 parts by weight of molten fly ash B shown in Table 1, 35 parts by weight of blast furnace slag powder (Brain specific surface area: 4330 cm ² / g) and 2 parts by weight of slaked lime were added, and water at 25 ° C. was further added. 30
Add 40 parts by weight while kneading with a backflow high-speed kneader.
The following granulated material was cured at 60 ° C. for 15 hours. The crushing strength of the treated product was 2 kg (10 mm particles), and the leaching amount of harmful heavy metals in the leaching test based on the Environment Agency Notification No. 46 exceeded the soil environmental standard. Note that the temperature was maintained at 60 ° C. in a closed chamber by introducing a small amount of steam.

[0038]

Since the present invention is configured as described above, it has the following effects. (1) Since all of the molten fly ash is solidified and stabilized by a semi-dry treatment without generating exhaust gas and wastewater, a self-contained system that does not generate new waste can be provided. (2) Pulverized slag (having hydraulic properties) obtained by pulverizing molten slag (water-cooled slag) from a melting furnace that has generated molten fly ash is kneaded with molten fly ash, so that slag and the like are added from outside the melting furnace. There is no need to transport and introduce agents, and other additives can be unnecessary or minimized. (3) Add the same amount or more of pulverized slag of molten slag to molten fly ash, add lime etc. as necessary, and knead, or knead and press-mold, then cure at room temperature and further steam cure. By doing so, a lot of hydrates are generated, so that harmful heavy metals are fixed against changes in the composition of molten fly ash and changes in the content of harmful heavy metals, and good strength in handling properties is secured. can do. That is, it can be applied to various types of molten fly ash having different compositions. (4) By performing granulation by stirring kneading or molding by pressure molding after stirring and kneading, and then performing curing treatment, the strength and stability of the processed product are improved, and handling properties are improved. (5) In the room temperature curing treatment, the strength and stability of the treated product are improved by hydration reaction products generated by a large amount of pulverized slag, and harmful heavy metals are fixed. it can. By further performing the steam curing process, the hydration reaction is more advanced, and there is no free lime, toxic heavy metals can be more secured, it is possible to satisfy the environmental quality standards for soil. ( 6 ) When the final product is crushed, it has a wide particle size distribution due to irregular shaped particles, and can be effectively used as civil engineering material.

[Brief description of the drawings]

1 is a schematic diagram showing an apparatus for carrying out the solidification and stabilization processing method molten fly ash according to a first embodiment of the present invention.

2 is a schematic diagram showing an apparatus for carrying out the solidification and stabilization processing method molten fly ash according to the second embodiment of the present invention.

Figure 3 is a schematic diagram showing an apparatus for carrying out the solidification and stabilization processing method molten fly ash according to a third embodiment of the present invention.

4 is a schematic diagram showing an apparatus for carrying out the solidification and stabilization processing method molten fly ash according to the fourth embodiment of the present invention.

5 is a schematic diagram showing an apparatus for carrying out the solidification and stabilization processing method molten fly ash according to the fifth embodiment of the present invention.

6 is a schematic diagram showing an apparatus for carrying out the solidification and stabilization processing method molten fly ash according to a sixth embodiment of the present invention.

[7] Oite room temperature curing to a sixth embodiment of the present invention
It is a schematic block diagram which shows an example of the principal part of a structure provided with the processing part and the steam curing processing part .

FIG. 8 is a schematic configuration diagram showing a main part of an apparatus for performing a method of solidifying and stabilizing molten fly ash according to a seventh embodiment of the present invention.

FIG. 9 is a schematic configuration diagram showing a main part of an apparatus for performing a method for solidifying and stabilizing molten fly ash according to an eighth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Melted fly ash hopper 12 Kneader 14 Ash meter 16 Ash supply line 18 Feeder 20 Slag hopper 21 Slag slurry tank 22 Crusher 23 Wet pulverizer 24 Slag meter 26 Slag supply line 28 Water supply pump 30 Water supply line 32 Room temperature Curing treatment room 34 Water tank 36, 38, 48, 68, 73, 76, 84 Conveyor 40, 41 Processed material 42 Melting furnace 44 Dust collector 45 Crushed material 46 Dryer 49 Slurry conveying means 50 Pressure forming machine 52, 58 Additive storage tank 54, 60 Additive measuring machine 56, 62 Additive supply line 64 Room temperature curing machine 66 Steam curing machine 70 Feeder 72 Discharger 74 Crusher 75 Primary crusher 78 Secondary crusher 80 Screener 82 Distributor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B09B 3/00 301 C04B 18/04

Claims (6)

(57) [Claims] 1. A slag melt-processed in a melting furnace is crushed with respect to 10 parts by weight of a molten fly ash captured from an exhaust gas from a melting furnace to obtain a crushed slag having a Blaine specific surface area of 2000 cm ² / g or more. ２００200 parts by weight, and after granulation while kneading with water, the kneaded granules are cured at room temperature to 55 ° C., and then cured under a saturated steam atmosphere at 60-98 ° C. Characteristic solidification and stabilization method of molten fly ash. 2. A slag melt-processed in this melting furnace is pulverized with respect to 10 parts by weight of molten fly ash captured from exhaust gas from the melting furnace to obtain a pulverized slag having a Blaine specific surface area of 2000 cm ² / g or more. ２００200 parts by weight, and after kneading with water, the kneaded product or the kneaded granule is subjected to pressure molding, and then the molded product is subjected to curing treatment in a range of room temperature to 55 ° C. A method for solidifying and stabilizing molten fly ash, which comprises curing in a saturated steam atmosphere. 3. When the content of CaO in the molten fly ash is less than 10 wt%, it is selected from the group consisting of quick lime, slaked lime, limestone, gypsum, caustic soda and calcium chloride per 10 parts by weight of the molten fly ash. The method for solidifying and stabilizing molten fly ash according to claim 1 or 2 , wherein 0.01 to 10 parts by weight of at least one of the additives is added. After a wherein molten slag were dried, ground to claim 1, 2 or 3 solidification and stabilization processing method molten fly ash according to Blaine specific surface area of 2000 cm ² / g or more powder slug. 5. The method for solidifying and stabilizing molten fly ash according to claim 1 , wherein one of industrial water and seawater is used as the kneading water. 6. The final product is crushed to a size of 0.05 to 40 mm.
Solidifying and stabilization process of molten fly ash according to any one of claims 1 to 5, granules having a particle size distribution.