JP2003012355A - Method for producing artificial lightweight aggregate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing at low cost an artificial light- weight aggregate with high strength and stable quality from incineration fly ash containing chlorine compounds and main ash. SOLUTION: This method for producing an artificial lightweight aggregate comprises the steps of adding a caking additive, a compositional adjuster and a reducing agent to incineration fly ash or main ash of municipal waste so that the chemical composition and the content of the chlorine compound become proper levels in the fired aggregate, mixing and crushing, molding the crushed mixture and heat treating the obtained molding in a furnace. This method enables to largely lower the treating cost of incineration fly ash or main ash and investment in the treating facility, and further to contribute greatly to the solution of waste recycling and environmental problem.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the recycling of fly ash or main ash scattered in exhaust gas when incinerating municipal waste,
More specifically, the present invention relates to a method for producing harmful aggregates in incinerated fly ash or main ash, as well as a method for producing an aggregate used for construction, civil engineering, and the like.

[0002]

The present inventors volatilize and remove heavy metals such as lead, zinc, and cadmium contained in fly ash or main ash by a method of burning fly ash or main ash, and for building, civil engineering, etc. We have developed methods for manufacturing the aggregates used. However, S, which is the main chemical constituent of fly ash or main ash
_{iO 2, Al 2 O 3,} CaO, there is an optimum range for aggregate reduction for _Fe 2 _{O 3,} the alkali component of the alkali metals is the main component other than this, mainly NaCl,
It has been found that chlorides such as KCl are contained in fly ash or main ash, and the content of these in fly ash or main ash varies greatly depending on the type of refuse incinerator and the method of treating exhaust gas. Also, the effect of the amount of alkali chloride in the raw material on the aggregate properties has not been systematically understood. Therefore, it has been desired to develop a technique for firing an aggregate having a predetermined quality by grasping the influence on the physical properties of the aggregate due to the fluctuation of the amount of chlorine or alkali chloride in the fly ash or the main ash as a raw material.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such a situation as described above, and it is a small amount and easily available addition of incineration fly ash or main ash in which chlorine compounds vary greatly depending on the source. It is intended to propose a method for producing an artificial aggregate, which can produce a high-strength and stable quality aggregate by using the agent.

[0004]

Means for Solving the Problems The inventors of the present invention have used incineration fly ash or main ash of municipal solid waste, a composition compounding agent and a reducing agent,
SiO ₂ in the fired aggregate is 30 to 75% by weight, Al ₂
O ₃ is 30 wt% or less, CaO is 35 wt% or less, Fe
₂ O ₃ is 2 to 15 wt%, (Na ₂ O + K ₂ O) is 6 to
It has a strength, a specific gravity characteristic and a chemical quality that can be used as an aggregate for civil engineering and construction when it is blended so that the content of chlorine in the raw material is within a specific range and it is fired in a rotary kiln. It has been found that high quality aggregate with low water absorption can be fired.

That is, a method of manufacturing an artificial aggregate according to the present invention
The law is that the incineration fly ash of municipal solid waste or the main ash is mixed with a binder and its composition is adjusted.
The chemical composition of the aggregate obtained by adding the mixture and the reducing agent is S
iO _Two30-75% by weight, Al_TwoO_ThreeIs less than 30% by weight
Below, CaO is 10 to 35% by weight, Fe_TwoO_ThreeIs 2 to 15
% By weight, (Na_TwoO + K_TwoO) is 6 to 15% by weight
And the content rate of chlorine compounds in the raw material is 8 in terms of chlorine amount.
~ 15% by weight or less of the mixture obtained by blending
Are mixed and pulverized so that the average particle size is 15 μm or less,
If necessary, a molded body obtained by molding water by adding water to the pulverized product is used.
After drying, the molded product is heat treated in a firing furnace.
It is a characteristic. In the manufacturing method of this artificial aggregate
As a binder, bentonite, molasses, or pulp
At least one kind of waste liquid can be used. Also, the same
As the iron source for the composition composition of the urine, steat or hematata
It is possible to use divalent or trivalent iron oxides such as iron
Similarly, as a reducing agent, carbonization of coal, coke, etc.
At least one compound is used to convert the amount of carbon in the raw material
It is preferable to add 0.5 to 9% by weight. further,
Quartz sand, porcelain stone, feldspar, kaori as the silica source of the composition compounding material
Knight, Kibushi viscosity, incinerator ash, coal ash, sewer incinerator sludge
At least one of the above can be used. The present invention
The molding method used in
As long as you can do it, there is no problem, but a pan pelletizer or
It is convenient to use an extrusion molding machine. Also, the firing method
As for the promotion of volatilization of harmful substances, continuous operation, and uniformity of quality
Considering the above, it is preferable to use a rotary kiln.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the SiO ₂ content in the calcined aggregate is limited to 30 to 75% by weight because the amount of glass phase produced in the calcined aggregate is insufficient when the content is less than 30% by weight. A high-strength aggregate cannot be obtained and the durability of the aggregate is reduced. On the other hand, when it exceeds 75% by weight, the raw material for chemical composition adjustment is several times the weight of the incineration ash to be treated, and the firing temperature is 12
This is because the fuel cost exceeds 50 ° C., the heat resistance of the firing equipment needs to be high, and the maintenance cost also increases, which is not practical.

Al ₂ O ₃ in the aggregate is limited to 30% by weight or less because when the amount exceeds 30% by weight, the firing temperature is 1%.
This is because it is not economical because it becomes 250 ° C or higher.

The amount of CaO in the aggregate is limited to 10 to 35% by weight, and it is preferable that the amount of CaO is small. However, if it is less than 10% by weight, the amount of CaO commensurate with the amount of alkali metal is additionally accompanied by excess alkali metal. It is not preferable because the viscosity of the matrix during heating is remarkably lowered to promote the fusion of the aggregate, and on the other hand, when it exceeds 35%, it is C against alkali metal.
This is because the amount of aO becomes too large, the firing temperature becomes 1250 ° C. or higher, the energy cost becomes excessive, and there is a problem in economic efficiency.

Fe ₂ O ₃ in the aggregate contributes to the liquid phase sintering of the matrix as a solvent when it is reduced inside the aggregate and mainly exists as FeO, and on the surface of the aggregate, it is excessive in the combustion gas for firing. When oxidized with oxygen from air and made to exist in the form of Fe ₂ O ₃ , a high temperature is required to generate a liquid phase from the inside of the aggregate, and the fusion between the aggregates in the firing furnace such as a rotary kiln and the inner wall of the furnace is caused. While having the effect of promoting the sintering inside the aggregate while improving the strength of the aggregate as a whole, if it is less than 2% by weight, this effect is insufficient and high-strength aggregate cannot be fired.
On the other hand, if it exceeds 15% by weight, the temperature range from liquid phase formation to slag formation becomes extremely narrow, and it becomes difficult to fire a homogeneous and high-strength aggregate, so that Fe ₂ O ₃ in the aggregate is 2 to 1
It was limited to 5% by weight.

Most of the chlorine compounds in fly ash or main ash
Become an alkali metal compound such as NaCl or KCl
There is. Alkali when the chlorine content in the raw material is less than 1% by weight
If the amount of metal is (Na_TwoO + K_TwoO) as less than 2% by weight
Therefore, the intention temperature rises below the liquid phase formation during firing,
It is not preferable in terms of aspect. Chlorine turns into chlorine when chlorine content is 1 to 10% by weight
The combined alkali metal works effectively as a solvent component,
Contributes to the formation of liquid phase at 750 ° C or higher 1000-12
It contributes to the firing of aggregate having high strength at 50 ° C. This place
The total alkali metal content is (Na_TwoO + K_Two2) as O)
It is 15% by weight. The alkali metal has a firing temperature of 100.
Volatile in combustion gas at 0 ~ 1250 ℃, 1 of unburned raw material
0-60% by weight is lost. Chlorine content is higher than 15% by weight
When the aggregate raw material is heated, the molten material of alkali chloride is the raw material
To fill the matrix and reduce the strength of the aggregate.
When soaking the aggregate in water after firing, a large amount of
Potassium elutes in water and significantly reduces the aggregate strength after drying.
Therefore, it is not preferable. The amount of chlorine in the raw material is 1 to 5 weight
%, The amount of alkali metal in the solidified body is (Na_TwoO + K
_Two2) to 6% by weight as O) and is combined with chlorine
Almost all of the alkali metal acts as a solvent when firing the aggregate.
It is preferable because it can fire high-strength aggregate at a relatively low temperature.
Good Therefore, (Na_TwoO + K_TwoO) is 2 to 15 layers
The amount was set to%.

A reducing agent such as coal or coke is added in order to control the oxidation state of iron. The reducing agent is added in an amount adjusted according to the reduction state of iron, and the addition amount is in the range of 0.5.
It is preferably about 9% by weight.

In many cases, the content of silica in fly ash is less than the proper composition. In this case, silica sand, porcelain stone, feldspar, kaolinite, kibushi clay, incineration main ash, coal ash, sewage incineration sludge, or other silica or a mineral containing silica and alumina is added to adjust the composition. In addition, chlorine in fly ash is often higher than the proper range for forming aggregate. In this case, the above-mentioned mineral containing silica or alumina is added to adjust to an appropriate range.

The average particle size of incinerated fly ash or main ash is about several μm. However, since the incinerated fly ash or main ash and the raw material for component adjustment have large average particle diameters, the raw materials are adjusted and further used as a binder. The bentonite is added, and then mixed while being crushed by a crusher such as a vibration mill to have an average particle size of 15 μm or less.
This is because if the average particle size exceeds 15 μm, the aggregate strength decreases, which is not preferable.

In the next molding step, the mixed and pulverized raw materials are added with water to form pellets having a diameter of 5 to 15 mm by tumbling granulation or extrusion granulation, followed by firing in a rotary kiln. Since the rotary kiln has a simple facility, the combustion gas flow for heating and the raw material are likely to come into contact with each other, and the residence time at a high temperature is long, which is several tens of minutes, so that volatilization of heavy metals into the gas is facilitated. Further, it is preferable as a facility for firing the aggregate because there is little variation in the quality of the fired aggregate and the reliability is high when the heavy metal is less eluted and is rendered harmless.

In the case of firing in a rotary kiln, when the raw material pellets roll and move in the kiln, they are worn away and pulverized. If the amount of pulverization is large, it will adhere to the pellets in the calcination section, and the adhesion to the pellets and to the inner wall of the kiln will increase, making the calcination operation difficult and reducing the actual yield and increasing the load on the dust collection facility. Therefore, it is not preferable. As a measure against this, in the present invention, a binder such as bentonite, pulp waste liquor or molasses is added to a raw material containing a component adjusting mineral as a binder in order to reduce pulverization in the kiln.

[0016]

[Examples] Examples 1-1 to 1-3 Fly ash used in the experiment changes the chlorine concentration, so the fly ash itself and the fly ash washed with water, filtered and dried (hereinafter referred to as "washed fly ash") are used.
It was used. In addition, sodium chloride was used to adjust the amount of chlorine. Table 1 shows the chemical composition of incineration fly ash or main ash, water-washed fly ash, silica sand, bentonite, hematite, coke, and sodium chloride used in the experiment. These raw materials were weighed out in the formulations shown in Table 2, pulverized and mixed by a vibration mill. The particle size distribution of the pulverized raw material was measured by a laser diffraction type particle size distribution meter. While adding water to the obtained pulverized raw material, it was granulated into a cylindrical shape having a diameter of about 10 mm by an extrusion molding machine and dried, and then a rotary kiln (brick inner diameter 920 to 700 mm ×
The length was 12000 mm and the material was fired at the firing temperature shown in Table 4. The chemical composition of the aggregate after firing and the chlorine concentration in the prepared raw material are shown in Table 3, and the average particle size of the raw material is shown in Table 4. The specific gravity of the calcined aggregate was measured based on JIS A 1110, and the aggregate strength was measured at 20 points for each sample by applying a load when the aggregate was pressed and broken from the direction perpendicular to the cylinder axis. The average value is shown in Table 4 as the crush strength. As is clear from the results shown in Table 4, the firing temperature is 1050 to 10
A high-strength aggregate having a crush strength of 880 to 1270 N at 70 ° C. was obtained.

Comparative Example 2-1 30 to 75% by weight of SiO _{2 and} 30% by weight of Al ₂ O ₃
Less, CaO less than 35 wt%, Fe ₂ O ₃ 2-15
Calcination was performed in the same manner as in Example except that the raw material was blended so that the chlorine concentration in the raw material was more than 10 wt% using sodium chloride, but the strength of the aggregate was not sufficiently expressed. .

Comparative Examples 2-2 to 2-7 Comparative Example 2-2 has less than 30% by weight of SiO ₂ in the aggregate, Comparative Example 2-3 has more than 75% by weight of SiO ₂ in the aggregate,
Comparative Example 2-4 has more than 30 wt% of Al ₂ O ₃ in the aggregate, Comparative Example 2-5 has more than 35 wt% of CaO in the aggregate, and Comparative Example 2-6 has Fe in the aggregate. ₂ O ₃ is less than 2% by weight, and in Comparative Example 2-7, the aggregate was fired by the same method as in Example except that the raw materials were blended so that Fe ₂ O ₃ in the aggregate was more than 15% by weight. Was not sufficiently expressed.

Comparative Example 2-8 The strength development of the aggregate fired by the same method as in Example 1-3 was not sufficient, except that the average particle size of the crushed raw material was 15 μm or more.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

Examples 1-4 to 1-7 Incinerator fly ash having a high chlorine concentration was obtained and used in the experiment.
Table 5 shows the chemical composition of incineration fly ash, water-washed fly ash, silica sand, bentonite, hematite, coke, and sodium chloride used in the experiment. These raw materials were weighed out in the formulations shown in Table 6 and pulverized and mixed by a vibration mill. The particle size distribution of the pulverized raw material was measured by a laser diffraction type particle size distribution meter. While adding water to the obtained crushed raw material, a diameter of about 10 is obtained by an extrusion molding machine.
After granulating into a cylindrical column of mm and drying, a rotary kiln (brick inner diameter 920 to 700 mm x length 12000 mm)
And was fired at the firing temperature shown in Table 8. Table 7 shows the chemical composition of the aggregate after firing and the chlorine concentration in the prepared raw material.
Table 8 shows the average particle size of the raw materials. The specific gravity of the calcined aggregate was measured based on JIS A 1110, and the aggregate strength was measured at 20 points for each sample by applying a load when the aggregate was pressed and broken from the direction perpendicular to the cylinder axis. The average value is shown in Table 8 as the crush strength. As is clear from the results shown in Table 8, the crushing strength is 87 at the firing temperature of 1110-1210 ° C.
A high-strength aggregate of ~ 133N was obtained.

Comparative Examples 2-9, 2-10 30 to 75 wt% of SiO _{2 and} 30 wt% of Al ₂ O ₃
Below, CaO is 10 to 35% by weight, and Fe ₂ O ₃ is 2-1.
5% by weight, but the chlorine concentration in the raw material is less than 8% by weight and 1
Firing was performed in the same manner as in the example except that the raw materials were blended so as to be more than 5%, but the strength of the aggregate was not sufficiently expressed.

Comparative Examples 2-11 and 2-12 The raw materials were mixed so that the chlorine concentration in the raw materials was 8 to 15% by weight, and SiO ₂ in the fired aggregate was 30 to 75% by weight and Al ₂ O ₃ is 30 wt% or less, Fe ₂ O ₃ is 2-1
5% by weight, CaO less than 10% by weight or 35% by weight
The firing was performed in the same manner as in the examples except for the above, but the strength of the aggregate was not sufficiently expressed.

Comparative Examples 2-13 to 2-17 In Comparative Example 2-13, SiO ₂ in the aggregate is less than 30% by weight,
In Comparative Example 2-14, SiO ₂ in the aggregate is more than 75% by weight, and in Comparative Example 2-15, Al ₂ O ₃ in the aggregate is 30% by weight.
More, Comparative Examples 2-16 are _Fe 2 _{O 3} in the aggregate is less than 2 wt%, Comparative Example 2-17 _Fe 2 _{O 3} in the aggregate
Was fired in the same manner as in Example except that the raw materials were blended so that the content was more than 15% by weight, but the strength of the aggregate was not sufficiently expressed.

Comparative Example 2-18 Firing was carried out in the same manner as in Example 1-5 except that the average particle size of the crushed raw material was set to 15 μm or more, but the strength development of the aggregate was not sufficient.

[0029]

[Table 5]

[0030]

[Table 6]

[0031]

[Table 7]

[0032]

[Table 8]

Examples 1-8 to 1-10 In the fly ash used in the experiment, the fly ash itself and the fly ash which was washed with water, filtered and dried (hereinafter referred to as the water washed fly ash) were used in order to change the amounts of alkali metal and chlorine. In addition, sodium chloride was used to adjust the amount of alkali metal and chlorine. The incineration fly ash used in the experiment, the wash fly ash, silica sand, bentonite, hematite,
Table 9 shows the chemical composition of coke and sodium chloride.
These raw materials were weighed out in the formulations shown in Table 10 and pulverized and mixed by a vibration mill. The particle size distribution of the pulverized raw material was measured by a laser diffraction type particle size distribution meter. While adding water to the obtained pulverized raw material, it was granulated into a columnar shape having a diameter of about 10 mm by an extrusion molding machine and dried, and then the rotary kiln (brick inner diameter 920
Up to 700 mm x length 12000 mm), Table 12
It was fired at the firing temperature shown in. The chemical composition of the aggregate after firing and the chlorine concentration in the prepared raw material are shown in Table 11, and the average particle size of the raw material is shown in Table 12. The specific gravity of the fired aggregate is JIS
The aggregate strength was measured based on A 1110, and the load at the time of breaking by pressurizing from a direction perpendicular to the cylindrical axis of the cylindrical aggregate was measured at 20 points for each sample, and the average value was used as the crush strength. It was shown to. As is clear from the results in Table 12, the crushing strength is 88 to 127 at a firing temperature of 1050 to 1070 ° C.
A high-strength N aggregate was obtained.

Comparative Example 2-19 30 to 75% by weight of SiO _{2 and} 30% by weight of Al ₂ O ₃
Less, CaO less than 35 wt%, Fe ₂ O ₃ 2-15
It was burned in the same manner as in Examples 1-8 to 1-10, except that the raw material was blended so that the chlorine concentration in the raw material was less than 10 wt% using sodium chloride, although the amount was wt%. The strength of the material was not sufficiently expressed.

Comparative Examples 2-20 to 2-25 In Comparative Example 2-20, SiO ₂ in the aggregate is less than 30% by weight,
In Comparative Example 2-21, SiO ₂ in the aggregate is more than 75% by weight, and in Comparative Example 2-22, Al ₂ O ₃ in the aggregate is 30% by weight.
More, Comparative Example 2-23 has more than 35 wt% CaO in the aggregate, Comparative Example 2-24 has ₂ Fe ₂ O ₃ in the aggregate.
% By weight, and Comparative Example 2-25 shows Fe ₂ O in the aggregate.
Firing was performed in the same manner as in Examples 1-8 to 1-10, except that the raw materials were blended so that ₃ was more than 15% by weight.
The strength of the aggregate was not sufficiently expressed.

Comparative Example 2-26 Firing was carried out in the same manner as in Example 1-10 except that the ground material had a mean particle size of 15 μm or more, but the aggregate did not exhibit sufficient strength.

[0037]

[Table 9]

[0038]

[Table 10]

[0039]

[Table 11]

[0040]

[Table 12]

Examples 1-11 to 1-14 Incinerator fly ash having a particularly high chlorine concentration was obtained and used in the experiment. Table 13 shows the chemical composition of incineration fly ash, water-washed fly ash, silica sand, bentonite, hematite, coke, and sodium chloride used in the experiment. These raw materials were weighed out in the formulations shown in Table 14, pulverized and mixed by a vibration mill. The particle size distribution of the pulverized raw material was measured by a laser diffraction type particle size distribution meter.
While adding water to the obtained pulverized raw material, it was granulated into a columnar shape having a diameter of about 10 mm by an extrusion molding machine and dried, and then a rotary kiln (brick inner diameter 920 to 700 mm x length 12000).
mm) and fired at the firing temperature shown in Table 16. Table 15 shows the chemical composition of the aggregate after firing and the chlorine concentration in the prepared raw material.
The average particle size of the raw materials is shown in Table 16. The specific gravity of the calcined aggregate was measured based on JIS A 1110, and the aggregate strength was measured at 20 points for each sample by applying a load when the aggregate was pressed and broken from the direction perpendicular to the cylinder axis. The average value is shown in Table 16 as the crush strength. As is clear from the results shown in Table 16, the firing temperatures 1110 to 1210
A high-strength aggregate having a crush strength of 87 N to 133 N at 0 ° C was obtained.

Comparative Examples 2-27 and 2-28 30 to 75% by weight of SiO _{2 and} 30% by weight of Al ₂ O ₃
Below, CaO is 10 to 35% by weight, and Fe ₂ O ₃ is 2-1.
5% by weight, (Na ₂ O + K ₂ O) is 6 to 15% by weight, but the chlorine concentration in the raw material was less than 8% by weight, and the raw materials were blended so as to be more than 15%. 1-
It was fired by the same method as No. 14, but the strength of the aggregate was not sufficiently expressed.

Comparative Examples 2-29, 2-30 The raw materials were mixed so that the chlorine concentration in the raw materials was 8 to 15% by weight, and SiO ₂ in the fired aggregate was 30 to 75% by weight, and Al ₂ O ₃ is 30 wt% or less, Fe ₂ O ₃ is 2-1
5% by weight, (Na ₂ O + K ₂ O) 6 to 15% by weight, but calcined in the same manner as in Examples 1-11 to 1-14 except that CaO is less than 10% by weight or 35% by weight or more. However, the strength of the aggregate was not sufficiently expressed.

Comparative Examples 2-31 to 2-35 In Comparative Example 2-31, SiO ₂ in the aggregate is less than 30% by weight,
In Comparative Example 2-32, SiO ₂ in the aggregate is more than 75% by weight, and in Comparative Example 2-33, Al ₂ O ₃ in the aggregate is 30% by weight.
More, Comparative Examples 2-34 are _Fe 2 _{O 3} in the aggregate is less than 2 wt%, Comparative Example 2-35 _Fe 2 _{O 3} in the aggregate
Was fired in the same manner as in Example except that the raw materials were blended so that the content was more than 15% by weight, but the strength of the aggregate was not sufficiently expressed.

Comparative Example 2-36 Firing was carried out in the same manner as in Example 1-12 except that the average particle size of the crushed raw material was 15 μm or more, but the strength development of the aggregate was not sufficient.

[0046]

[Table 13]

[0047]

[Table 14]

[0048]

[Table 15]

[0049]

[Table 16]

[0050]

INDUSTRIAL APPLICABILITY According to the present invention, incineration fly ash containing a large amount of chlorine compounds and main ash, which largely vary depending on the structure of the incinerator, the operation method and the fly ash collection method, are used as the exhaust gas treating agent. By adjusting the lime raw material within the specified range, it is possible to burn incineration fly ash or main ash as aggregate with high strength with a small amount of additives, which significantly improves the treatment efficiency of incineration fly ash or main ash. By increasing it, it is possible to greatly reduce the treatment cost and treatment equipment investment, and also contribute greatly to the recycling of waste and the elimination of environmental problems.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C04B 35/00 C04B 35/00 V 35/16 35/16 Z (72) Inventor Katsuhiro Tomoda Ichikawa City, Chiba Prefecture China 3-18-5 Sumitomo Metal Mining Co., Ltd. F-term (reference) 4G030 AA03 AA04 AA08 AA27 AA36 AA37 GA11 GA13 GA14 HA01 HA05 HA15 HA25

Claims (6)

[Claims] 1. The chemical composition of an aggregate obtained by adding a binder, a composition preparation material, and a reducing agent to incineration fly ash or main ash of municipal waste, and having a chemical composition of SiO ₂ of 30 to 75% by weight and Al ₂ O. ₃ is 30
% Or less, CaO is 10 to 35% by weight, Fe ₂ O ₃ is 2 to 15% by weight, (Na ₂ O + K ₂ O) is 6 to 15% by weight, and the content of the chlorine compound in the raw material is the amount of chlorine. A molded product obtained by mixing and pulverizing a mixture obtained by blending so as to be 8 to 15% by weight or less so as to have an average particle size of 15 μm or less, and adding water to the pulverized product to form the mixture. Is dried, if necessary, and then the molded body is heat-treated in a firing furnace. 2. The method for producing an artificial aggregate according to claim 1, wherein at least one of bentonite, molasses, and pulp waste liquid is used as the binder. 3. The method for producing an artificial aggregate according to claim 1, wherein a divalent or trivalent iron oxide such as wustite or hematite is used as an iron source of the composition preparation material. 4. The method according to claim 1, wherein at least one carbon compound such as coal and coke is used as a reducing agent, and 0.5 to 9% by weight in terms of carbon amount is added to the raw material.
4. The method for manufacturing an artificial aggregate according to any one of 3 to 3. 5. The method according to claim 11, wherein at least one of silica sand, porcelain stone, feldspar, kaolinite, wood knot viscosity, incinerated main ash, coal ash, and sewer incineration sludge is used as a silica source of the composition blending material. 4. The method for manufacturing an artificial aggregate according to any one of 4. 6. The method for producing an artificial aggregate according to claim 1, wherein the molded body is a pellet and a rotary kiln is used as a firing furnace.