JPH0829312B2 - Method for producing slag by melting waste - Google Patents

Description

Detailed Description of the Invention

[0001]

[Field of Industrial Application] The present invention relates to construction sludge (mud discharged from construction work by shield excavation method, pile driving method, etc.),
Method for producing high-strength and rugged slag by melting and processing waste such as water and sewage sludge, municipal waste incineration ash, shredder dust incineration ash, sludge from food / pulp and pulp mill, coal ash, etc. Is. The slag produced by the method of the present invention is used for earthwork materials (sand drain materials, sand compaction materials, backfill materials, etc.), pavement materials (roadbed materials,
It can be used for sidewalk materials, etc.), concrete aggregates, wall materials, gardening materials, filtration materials, building materials, etc.

[0002]

2. Description of the Related Art In recent years, it has become difficult to secure a waste disposal site, and not only stabilization and volume reduction of waste but also recycling is required. Conventionally, as a slag manufacturing method by water cooling, if necessary, a CaO source material or the like is added to the waste for the purpose of lowering the melting point, melted at a temperature of 1300 to 1600 ° C, and is 0 to more than the boiling temperature of the melting furnace atmosphere pressure. There is known a method of producing slag by flowing it down into water at a temperature of the end (temperature changes depending on the amount of slag, etc., day and night) in a range lower by 80 ° C. Further, the liquid pH is not adjusted, and the liquid pH is usually 6.0 to 9.0, and in most cases, the pH is 7.0 to 8.0.
Met. Therefore, it was difficult to manufacture a slag having high strength, unevenness on the surface, and stable quality.

In Japanese Patent Laid-Open No. 63-20099, a molten slag falling from a melting furnace is received by a receiver equipped with a cooling means and a vibrating means, and indirectly cooled to form a granular solidified body. A treatment method for sewage sludge molten slag that is continuously taken out is described.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the method described in Japanese Patent Publication No.
The slag is cooled at a high temperature, and part of the temperature range is common with the present invention, but since it is used for indirect water cooling or indirect air cooling, the cooling part area is small, and a large amount of melt due to waste melting It is difficult to stably cool and convey the same at the same temperature. In addition, since it is indirect cooling, the liquid pH
Therefore, the slag cannot be hydrothermally treated.

Further, in the above-mentioned conventional technique, a water-cooled slag satisfying the following four conditions cannot be obtained. (1) High-strength slag equivalent to natural sand, (2) Slag having irregularities on the surface, (3) Slag having an appropriate particle size distribution as a civil engineering building material, (4) Slag of stable quality, the present invention In order to obtain the slag satisfying the above (1) to (4), the inventors conducted various studies and found that the slag was 2 to 5% higher than the boiling temperature of the melting furnace atmosphere pressure.
A slag satisfying (1) to (4) is obtained by maintaining the temperature at ± 10 ° C in the low range of 0 ° C and allowing it to flow down into hot water having a liquid pH of 8.0 to 13.0 for cooling. I found that I can do it. Furthermore, it was found that the unevenness of the slag surface can be increased by treating the crushed slag in hot water having the same properties as the hot water for cooling the melt. The present invention was made based on the above findings,
It is an object of the present invention to provide a slag manufacturing method capable of obtaining a slag having high strength and unevenness on the surface.

[0006]

In order to achieve the above object, a method for producing slag by melting waste according to a first aspect of the present invention is as follows: As shown in FIG. It is maintained at ± 10 ° C within the range of 2 to 50 ° C lower than the boiling temperature of the atmospheric pressure , and the pH is adjusted to 8.0 to 13.0.
In hot water that is integer, the melt flowing down and cooling to is characterized by obtaining a slag. 10 is a melting furnace, 12 is a water cooling device, 14 is a hot water container, 16 is a crusher, and 18 is a pump. In FIG. 1, within the range of 2 to 50 ° C., preferably 5 to 20 ° C. lower than the boiling temperature of the melting furnace atmosphere pressure, ± 10
The slag is produced by causing the melt to flow down into the circulating hot water maintained at ℃, preferably ± 5 ℃ and cooling.
And it becomes a product by crushing with the crusher 16. The temperature of the circulating hot water is controlled, for example, by detecting the hot water temperature in the hot water container 14 and adjusting the cold water supply amount.

The pH of the hot water is adjusted by adding a pH adjuster to the circulating system, for example, the hot water container 14,
The pH is adjusted to 8.0 to 13.0, preferably 9.0 to 12.0. The method according to claim 2 is the method according to claim 1 , wherein the waste is CaO source material, Fe ₂ O ₃ source material, and Si.
The composition is adjusted by adding an additive material selected from the group consisting of O ₂ source materials, and then melted . Furthermore, in the method of claim 3, in the method of claim 1 or 2 , as shown in FIG. 2, after crushing the slag, the crushed material is heated in hot water having the same properties as hot water for cooling the melt. .5～20 hours to Monodea
It 2 shows that the slag crushed by the crusher 16 is treated in hot water for cooling the melt in the hydrothermal treatment container 20 or in hot water having the same properties as the hot water for cooling the melt, thereby improving the quality. 3 shows a method for producing the improved slag. 22 is a solid-liquid separator and 24 is a pump.

[0008] The atmospheric pressure of the melting furnace is usually normal pressure in most cases, but the atmospheric pressure is increased in a coal gasification furnace or the like. In the normal pressure state, the hot water temperature is maintained at 50 to 98 ° C., preferably 80 to 95 ° C., ± 10 ° C., preferably ± 5 ° C., but in the pressurized state, the hot water temperature is water. It is maintained at ± 10 ° C, preferably ± 5 ° C in the range of 2 to 50 ° C, preferably 5 to 20 ° C lower than the boiling temperature of. Under high pressure such as in a coal gasifier, slag is taken out from the water cooling device 12 from the bottom of the water cooling device.

As the melting furnace 10, an electric furnace using electricity, gas, oil, coal, coke, combustible dust, waste materials, etc. as a heat source, a surface melting furnace, a swirling melting furnace, a coke bed melting furnace and the like are used. As the water cooling device 12, a device for controlling the temperature and / or the liquid pH while the container is filled with hot water and circulated by the pump 18 is used. As the crusher 16, an impact crusher such as a hammer mill whose particle size can be easily adjusted by adjusting the rotation speed is used. As the hydrothermal treatment vessel 20, a type in which an outer jacket is kept warm by circulating hot water and slag is extracted from the bottom or a conveyor is extracted from the top is used.

As the hot water pH adjusting material, alkaline waste, lime, iron hydroxide, caustic soda and the like are used.
When adjusting to the acidic side, sulfuric acid, hydrochloric acid or the like is used. As the CaO source material for composition adjustment, lime, seashell,
Blast furnace slag, concrete pieces, lime sludge or the like is used as the Fe ₂ O ₃ source material, iron ore, steel sludge, iron oxide or the like is used as the SiO ₂ source material, silica sand, quartzite, Crushed stone, used foundry sand, residual soil, etc. are used. When the temperature of the cooling water (hot water) is lower than the boiling temperature of the melting furnace atmosphere pressure by more than 50 ° C., for example, under normal pressure,
If the cooling water temperature is less than 50 ° C., the particle size is large, and high strength slag having irregularities on the surface cannot be obtained. If it exceeds 98 ° C., the generated steam adversely affects the melting furnace. further,
When the pH of the liquid is 8.0 to 13.0, the slag is hydrothermally treated, and calcium silicate hydrate or the like is generated on the surface, so that the strength of the slag becomes large and the unevenness of the surface becomes large. If the liquid pH is less than 8.0, the hydrothermal treatment effect will be insufficient, and if the liquid pH exceeds 13.0, there will be a problem that the amount of residual alkali increases. Further, the hydrothermal treatment time is 0.
If it is less than 5 hours, the effect of hydrothermal treatment is insufficient, and 20
If the time is exceeded, the hydrothermal treatment container becomes large and there is a problem in economic efficiency. Furthermore, if hydrothermal treatment is carried out after crushing, all surfaces are hydrothermally treated, so that the quality of slag is further improved.
If the water temperature fluctuates more than ± 10 ° C, the slag quality fluctuates. That is, on the lower side, the particle size becomes smaller and the strength decreases, and on the higher side, the particle size becomes larger and the strength increases.

A CaO source material was added to the waste to adjust the melting point to 1
When the temperature is 350 ° C. or less and melts at 1400 ° C. to 1600 ° C., the change in melt flowability becomes small due to changes in the amount of slag, heat radiation of the furnace due to changes in outside temperature between day and night, etc. Stable in the hot water, high quality,
Moreover, slag with stable quality can be obtained. When the rotation speed of the crusher 16 is adjusted, the particle size of the slag is different. Therefore, in order to obtain an appropriate particle size for each application, a method such as crushing by changing the rotation speed or mixing slags with different rotation speeds is used. . The melting point is JIS M 880.
3 pyramid (2.7 x
(2.7 × 3.0 × 8 ^H mm) was placed in an electric furnace and heated at 5 ° C./min so that the height of the triangular pyramid was about 1/6 of the width.
Say the temperature when it became.

[0012]

Embodiments of the present invention will be described below. The crush strength is the strength with which spherical particles of 3 mm are broken using a Kiya type hardness meter. Example 1 20 parts of iron ore was added to 100 parts of construction sludge to prepare raw materials. The melting point of this mixture is 1300 ° C., it is melted at 1450 ° C. using a swirling melting furnace, and the temperature of the hot water for cooling, liquid p
H (adjusted with Ca (OH) ₂ ) was changed in 1 hour cycle to produce black slag under various water cooling conditions. As shown in FIG. 3, the relationship between the water temperature pH and the crush strength at the time of manufacturing slag crushed at a rotation speed of 2500 rpm becomes larger as the water temperature becomes higher, and the pH becomes 10.0 rather than 8.0. It was For comparison, the crush strength of crushed natural sand (hard sandstone) was measured to be 19 kg / 3 mmφ.
Thus, the slag having a water temperature of about 600 ° C. or higher and a strength higher than that of natural crushed sand was obtained. Also, the water temperature during production and 2500
FIG. 4 shows the relationship of the ratio of slag of 5 mm or more after crushing at the rotation speed of rpm. As shown in FIG. 4, the higher the water temperature, the more the liquid pH is 10.0 rather than 8.0, and the particles with a diameter of 5 mm or more are effective as terazotile-like aesthetic aggregates. Can be applied.

Example 2 Only dried construction sludge was used as a raw material and melted at 1550 ° C. in a swirling melting furnace to produce slag under various water cooling conditions, and the crusher was crushed at 3500 rpm.
Using the obtained slag, a mortar made of boltland cement with a water-cement ratio of 50% and a flow value of 190 ± 5 mm is prepared, poured into a 5φ × 10 cm mold and at 1 ° C. at 20 ° C.
It was demolded after daily curing and further cured for 6 days to measure the compressive strength. The relationship between the pH and temperature of hot water during production and the 7-day curing compressive strength of mortar is shown in FIG. From FIG. 5, the higher the water temperature, the higher the mortar strength, and the liquid pH is 8.0-1.
It can be seen that the maximum is 3.0. In the pH adjustment, Ca (OH) ₂ was used on the alkaline side and H ₂ SO ₄ was used on the acidic side.

Example 3 A raw material was prepared by adding 20 parts of iron ore to 100 parts of construction sludge. This mixture was melted at 1450 ° C. using a swirling melting furnace and dropped into hot water having a temperature of 90 ° C. and a pH of 10.0 to obtain slag. The rotation speed of this slag crusher is 3500 rp
It was crushed as m. The slag obtained is black and conforms to JIS
It had a particle size distribution satisfying A 5004 (crushed concrete sand). This slag is cooled with hot water (temperature 90 ° C,
It was treated under pH 10.0) for 2 hours. Crush strength is 23k
g / 3mmφ, mortar's 7-day strength (compression) is 4
70 kg / cm ² of natural crushed sand mortar
It showed a value 10% higher than the daily strength (compression) of 420 kg / cm ² , and the hydrothermal treatment after crushing made the slag simple substance and the mortar even stronger.

[0015]

Since the present invention is configured as described above, it has the following effects. (1) A slag with high strength and uneven surface can be obtained, which can be recycled as a natural crushed sand, a civil engineering building material, etc. as a substitute for sand. (2) When crushing the obtained slag, by reducing the rotation speed of the crusher, a large amount of high-strength slag with a particle size of 5 mm or more is obtained, and the color is black, so that it is similar to terrazotile. It can be applied to aesthetic aggregates with high added value.

[Brief description of drawings]

FIG. 1 is a process drawing showing an embodiment of a method for producing slag by melting waste according to the present invention.

FIG. 2 is a process drawing showing another embodiment of the method of the present invention.

FIG. 3 is a graph showing the relationship between hot water temperature and slag crush strength.

FIG. 4 is a graph showing a relationship between a water temperature of hot water and a slag ratio of a particle size of 5 mm or more after crushing slag.

FIG. 5 is a graph showing the relationship between the pH of hot water and the slag compressive strength after curing for 7 days.

[Explanation of Codes] 10 Melting Furnace 12 Water Cooling Device 14 Hot Water Container 16 Crusher 18 Pump 20 Hydrothermal Treatment Container 22 Solid-Liquid Separator 24 Pump

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C04B 5/00 C 5/06 // C04B 18/10 Z 18/16

Claims (3)

[Claims] 1. Hot water after melting the waste, maintained at ± 10 ° C. within a range of 2 to 50 ° C. lower than the boiling temperature of the melting furnace atmosphere pressure , and adjusted to pH 8.0 to 13.0. A method for producing slag by melting waste, characterized in that slag is obtained by flowing down and cooling a melt inside. 2. A waste material comprising CaO source material, Fe ₂ O ₃ source material,
After the composition prepared by adding an additive material selected from the group consisting of SiO ₂ source material, manufacturing method of the slag by waste melting 請 Motomeko 1, wherein you melt. 3. After crushing the slag, the crushed material is treated in hot water having the same properties as the hot water for cooling the melt for 0.5 to 20 hours.
That請 Motomeko 1 or 2 method for producing a slag by waste melt according.