JPH04326975A - Production of slag due to melting of waste - Google Patents

Abstract

PURPOSE:To reuse waste as resources of a civil-engineering and building material or the like in place of natural ground sand or the like by a method wherein waste is melted and the molten liquid is allowed to flow to hot water held to + or -10 deg.C within the range lower than the boiling temp. of the atmospheric pressure in a melting furnace by 2-50 deg.C to be cooled. CONSTITUTION:Additives are added to waste such as building sludge or water supply and drainage sludge to prepare a composition which is, in turn, melted in a melting furnace 10. The molten liquid is allowed to flow in a water cooling apparatus 12 whose water temp. held to + or -10 deg.C the range of 50-98 deg.C when the atmospheric pressure in the melting furnace is normal pressure but the atmospheric temp. of the melting furnace by 5-20 deg.C when atmospheric pressure is in a pressurized state to be cooled to prepare slag. The water cooling apparatus 12 is constituted so that a container is filled with hot water and the temp. of hot water is controlled while the hot water is circulated by a pump 18. The slag is taken out of the bottom part of the water cooling apparatus 12 in a pressurized state and ground by a grinder 16 to obtain a product. Since the particle size of the slag is different by adjusting the number of rotations of the grinder 16, the number of rotations is changed or a mixing method is used in order to obtain a proper particle size due to each use.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to construction sludge (sludge discharged from construction work using shield excavation method, pile driving method, etc.),
A method for manufacturing slag with high strength and an uneven surface by melting and processing wastes such as water and sewage sludge, municipal waste incineration ash, shredder dust incineration ash, sludge from food and pulp and paper factories, and coal ash. It is. The slag produced by the method of the present invention can be used as earthwork materials (sand drain materials, sand compaction materials, backfill materials, etc.), paving materials (road base materials,
It can be used for materials such as sidewalk materials, concrete aggregates, wall materials, gardening materials, filter materials, and building materials.

0002

BACKGROUND OF THE INVENTION In recent years, it has become difficult to secure waste disposal sites, and there is a demand for not only stabilization and volume reduction of waste, but also recycling. Conventionally, in the water-cooled slag manufacturing method, CaO source material etc. are added to the waste as necessary for the purpose of lowering the melting point, and the waste is melted at a temperature of 1300 to 1600°C, and the temperature is lower than the boiling temperature of the melting furnace atmosphere pressure. A method is known in which slag is produced by flowing it into water at a normal temperature (temperature changes depending on day and night, amount of slag, etc.) within a range of 80°C lower. In addition, the liquid pH is not adjusted, and the liquid pH is usually 6.
．． 0 to 9.0, and in most cases the pH was 7.0 to 8.0. Therefore, it has been difficult to produce slag with high strength, unevenness on the surface, and stable quality.

Furthermore, Japanese Patent Application Laid-Open No. 63-20099 discloses that the molten slag falling from the melting furnace is received in a receiver equipped with cooling means and vibration means, and is indirectly cooled to form a granular solidified body. A method for treating continuously extracted sewage sludge molten slag is described.

0004

[Problem to be solved by the invention] The above-mentioned Japanese Patent Application Laid-Open No. 63-2
In the method described in No. 0099, the temperature is 80 to 350°C.
The slag is cooled at a high temperature, which shares a part of the temperature range with the present invention, but since indirect water cooling or indirect air cooling is performed, the area of the cooling section is small and a large amount of melted liquid is generated by melting the waste. It is difficult to stably cool and transport materials at the same temperature. In addition, since indirect cooling is used, the liquid pH
It is not possible to hydrothermally treat slag due to the control of

[0005] Furthermore, with the above-mentioned conventional techniques, water-cooled slag that satisfies the following four conditions cannot be obtained. (1) High-strength slag comparable to natural sand, (2) Slag with uneven surface, (3) Slag with appropriate particle size distribution for civil engineering and construction materials, (4) Slag with stable quality, the present invention In order to obtain a slag that satisfies the above (1) to (4), they have conducted various studies and found that the temperature range is ±2 to 50 degrees Celsius lower than the boiling temperature of the melting furnace atmosphere pressure.
The temperature is maintained at 10°C, and/or the liquid pH is maintained at 8.0-13.
(1) to (4) are cooled by flowing down into hot water of 0.
) It was discovered that it is possible to obtain a slag that satisfies the following. Furthermore, it was discovered that by treating the crushed slag in hot water having the same properties as the hot water used to cool the melt, it was possible to increase the roughness of the slag surface. The present invention has been made based on the above findings, and an object of the present invention is to provide a method for manufacturing slag that can produce a slag with high strength and an uneven surface.

[0006]

[Means and operations for solving the problems] In order to achieve the above object, the method of manufacturing slag by melting waste according to claim 1, as shown in FIG. The method is characterized in that slag is obtained by flowing the melt into hot water maintained at ±10°C within a range of 2 to 50°C lower than the boiling temperature of the atmospheric pressure. 10 is a melting furnace, 1
2 is a water cooling device, 14 is a hot water container, 16 is a crusher, and 18 is a pump. In Figure 1, the melt is allowed to flow down into circulating hot water maintained at ±10°C, preferably ±5°C, within a range of 2 to 50°C, preferably 5 to 20°C, lower than the boiling temperature of the melting furnace atmospheric pressure. By cooling the slag, slag is produced. A product is then crushed by a crusher 16. The temperature of the circulating hot water is, for example, the temperature of the hot water container 14.
It is controlled by detecting the temperature of hot water inside and adjusting the amount of cold water supplied.

[0007] Furthermore, the method according to claim 2 is characterized in that after melting the waste, the melt is poured into hot water whose pH is adjusted to 8.0 to 13.0 and cooled to obtain slag. There is. The pH adjustment of the hot water is carried out by adjusting the pH of the circulating system, for example, the hot water container 14.
This is done by adding an adjusting agent, and the pH is adjusted to 8.0 to 13.
．． 0, preferably adjusted to pH 9.0 to 12.0. Further, the method according to claim 3 is the method according to claim 1 or 2, in which the waste contains CaO source material, Fe2 O3 source material, SiO
2. It is characterized by adding additives selected from the group consisting of source materials to adjust the composition and then melting. Furthermore, the method of claim 4 is the method of claim 1, 2 or 3, comprising:
As shown in FIG. 2, the method is characterized in that after the slag is crushed, 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. FIG. 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. A method for producing improved slag is shown. 22 is a solid-liquid separator, and 24 is a pump.

[0008] The atmospheric pressure in a melting furnace is usually normal pressure in many cases, but in a coal gasification furnace, etc., the atmospheric pressure is in a pressurized state. In the case of a 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 case of a pressurized state, the hot water temperature is The temperature is maintained within a range of 2 to 50°C, preferably 5 to 20°C lower than the boiling temperature of ±10°C, preferably ±5°C. Under high pressure conditions such as in a coal gasifier, slag is removed from the water cooling device 12 from the bottom of the water cooling device.

As the melting furnace 10, an electric furnace, a surface melting furnace, a rotating melting furnace, a coke bed melting furnace, etc. using electricity, gas, oil, coal, coke, combustible garbage, waste materials, etc. as a heat source can be used. As the water cooling device 12, a device is used that fills a container with hot water and circulates it with a pump 18 while controlling the temperature and/or the pH of the liquid. Crusher 1
As No. 6, an impact crusher such as a hammer mill is used, which allows particle size to be easily adjusted by adjusting the rotation speed. As the hydrothermal treatment vessel 20, a type in which the external jacket is kept warm by circulating hot water and the slag is extracted from the bottom, or a type in which the slag is extracted from the top using a conveyor, etc. is used.

[0010] As the hydrothermal pH adjusting material, alkaline waste, lime, iron hydroxide, caustic soda, etc. are used. Moreover, when adjusting to the acidic side, sulfuric acid, hydrochloric acid, etc. are used. CaO source materials for composition adjustment include lime, shells,
Blast furnace slag, concrete pieces, lime-based sewage sludge, etc. are used, Fe2 O3 source materials include iron ore, steel sludge, iron oxide, etc., and SiO2 source materials include silica sand, silica stone, crushed stone, etc. Finished foundry sand, leftover soil, etc. are used. If the temperature of the cooling water (hot water) is more than 50°C lower than the boiling temperature of the melting furnace atmospheric pressure, for example under normal pressure, if the cooling water temperature is less than 50°C, the particle size will be large;
If a high-strength slag with an uneven surface cannot be obtained and the temperature exceeds 98°C, the generated steam will have an adverse effect on the melting furnace. Further, if the liquid pH is 8.0 to 13.0, the slag is hydrothermally treated and calcium silicate hydrate is generated on the surface, thereby increasing the strength of the slag and increasing the surface irregularities. 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 problems such as an increased amount of alkali remaining. Furthermore, if the hydrothermal treatment time is less than 0.5 hours, the hydrothermal treatment effect will be insufficient;
If the treatment time exceeds 20 hours, the hydrothermal treatment container becomes large and there is a problem in economical efficiency. Furthermore, if hydrothermal treatment is performed after crushing, the quality of the slag will be further improved since all surfaces will be hydrothermally treated. Furthermore, if the water temperature fluctuates more than ±10°C, the slag quality will fluctuate. In other words, when it is on the low side, the particle size becomes small and the strength decreases, and when it is on the high side, the particle size becomes large.
Moreover, the strength increases.

[0011] By adding CaO source material to the waste, the melting point is increased to 1.
If the temperature is 350°C or lower and melting is performed at 1400°C to 1600°C, changes in the fluidity of the melt will be small due to changes in the amount of slag, changes in the amount of heat released from the furnace due to changes in outside temperature between day and night, etc., and the state of the melt will change. It flows stably into hot water and is of high quality.
Moreover, slag with stable quality can be obtained. If the rotation speed of the crusher 16 is adjusted, the particle size of the slag will differ, so in order to obtain the appropriate particle size for each application, methods such as changing the rotation speed or mixing slags produced at different rotation speeds are used. . Note that the melting point is defined as JIS M 8.
801 (test method for coal), triangular pyramid (2.7
x 2.7 x 3.0 x 8H mm), it was placed in an electric furnace and heated at a rate of 5°C/min until the height of the triangular pyramid was approximately 1 inch of the width.
Say the temperature when it reaches /6.

0012

[Examples] Examples of the present invention will be described below. The crushing strength is the strength at which a 3 mm spherical particle breaks using a Kiya type hardness tester. Example 1 Raw materials were prepared by adding 20 parts of iron ore to 100 parts of construction sludge. The melting point of this mixture is 1300°C, and it is melted at 1450°C using a rotating melting furnace.
H (adjusted with Ca(OH)2) was varied in 1 hour cycles to produce black slag under various water cooling conditions. Water temperature and pH when producing slag crushed at a rotation speed of 2500 rpm
As shown in FIG. 3, the relationship between water temperature and crushing strength increased as the water temperature increased, and was greater at pH 10.0 than at pH 8.0. For comparison, we measured the crushing strength of natural crushed sand (hard sandstone) and found that it was 19 kg/3 mm.
φ, and when the water temperature was about 600° C. or higher, the slag had a strength higher than that of natural crushed sand. Also, the water temperature at the time of manufacture and 250
FIG. 4 shows the relationship between the percentage of slag with a diameter of 5 mm or more after crushing at a rotation speed of 0 rpm. As shown in Figure 4, the higher the water temperature, the higher the amount, and the amount is higher when the liquid pH is 10.0 than 8.0, and particles of 5 mm or more are effective for aesthetic aggregates such as terrazzo tiles. can be applied.

Example 2 Using only dried construction sludge as a raw material, slag was melted at 1550° C. using a rotating melting furnace to produce slag under various water-cooling conditions, and crushed at a crusher rotation speed of 3500 rpm. Using the obtained slag, a boltland cement mortar was prepared with a water-cement ratio of 50% and a flow value of 190±5mm, and poured into a 5φ x 10cm formwork and heated at 20°C.
After curing for one day, it was removed from the shape, further cured for 6 days, and the compressive strength was measured. FIG. 5 shows the relationship between the pH and temperature of hot water during production and the compressive strength of mortar after 7 days of curing. From Figure 5, the higher the water temperature, the higher the mortar strength, and the higher the liquid pH is 8.0 to 1.
It can be seen that it is maximum at 3.0. In addition, in pH adjustment, the alkaline side was performed using Ca(OH)2, and the acidic side was performed using H2SO4.

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 rotating melting furnace and poured into hot water at a temperature of 90° C. and a pH of 10.0 to form slag. The rotation speed of this slag crusher was set to 3500 rpm.
It was crushed as The obtained slag is black and JIS
It had a particle size distribution that satisfied A5004 (crushed concrete sand). This slag is heated with hot water (temperature 90℃) for cooling.
, pH 10.0) for 2 hours. The crushing strength is 23
kg/3mmφ, and the 7-day strength (compression) of the mortar is 470 kg/cm2, which is approximately 10% higher than the 7-day strength (compression) of 420 kg/cm2 of mortar made from natural crushed sand.
It showed a high value, and by hydrothermal treatment after crushing, the slag itself and the mortar became even stronger.

[0015]

[Effects of the Invention] Since the present invention is constructed as described above, it has the following effects. (1) A slag with high strength and uneven surface can be obtained.
It can be recycled as a civil engineering and construction material as a substitute for natural crushed sand or 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 can be obtained, and since it is black in color, it can be used for slag such as terrazzo tiles. It can be applied to aggregates for aesthetic materials with high added value.

[Brief explanation of drawings]

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

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

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

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

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

[Explanation of symbols]

10 Melting furnace 12 Water cooling device 14 Hot water container 16　Crushing machine 18 Pump 20 Hydrothermal treatment container 22 Solid-liquid separator 24 Pump

Claims (4)

[Claims] Claim 1: After melting the waste, the melt is cooled by flowing down into hot water maintained at ±10°C within a range of 2 to 50°C lower than the boiling temperature of the melting furnace atmospheric pressure to form slag. A method for producing slag by melting waste, characterized in that: [Claim 2] After melting the waste, the pH is 8.0 to 1.
A method for producing slag by melting waste, characterized in that slag is obtained by flowing and cooling the melt in hot water adjusted to a temperature of 3.0. [Claim 3] CaO source material, Fe2 O3 in waste
3. The method for producing slag by melting waste according to claim 1, wherein the slag is melted after adjusting the composition by adding an additive material selected from the group consisting of SiO2 source material and SiO2 source material. 4. 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. A method for producing slag by melting waste.