JP2002346535A - Method for manufacturing inorganic porous molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an inorganic porous molded product by which heavy metals and dioxins are removed or reduced to such a concentration that they are harmless and the incineration ash or the coal ash can be utilized as a useful resource, and a method for culturing algae using the inorganic porous molded product and the inorganic porous molded product. SOLUTION: The incineration ash or the coal ash 1 is molded 2 into briquets and these molded briquets are heated at 1,550 to 1,650 deg.C for not less than 30 minutes in an inert gas atmosphere under a melting step 3 to obtain a molten slag 4a. Next, this slag 4a is entered into water to precipitate a metal 11 while an inorganic expanded slag 4b is made afloat on the water. Further, the powdery inorganic material of the expanded slag 4b and the powder 19 of a nutrient for culturing the algae produced by removing a harmful component from the incineration ash of sewage sludge and water 16 are mixed 15 into the inorganic porous molded product with cavities and the molded product is aged 34 and made into an algae culturing medium 36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing harmful metals such as heavy metals and harmful organic compounds such as dioxins which are usually contained in incineration ash, coal ash or sewage sludge. Effective recycling of ash (recycling)
The present invention relates to a method for producing an inorganic porous molded body that has achieved the above.

[0002]

2. Description of the Related Art A large amount of incinerated ash generated from a general waste incineration plant and an industrial waste incineration plant and a large amount of coal ash generated from a coal-fired power plant have been almost completely discarded. Since incinerated ash and coal ash contain a large amount of components that can be reused as resources, there has been a strong demand for their reuse.

[0003] Regarding the method of recycling incinerated ash and coal ash,
Many uses for building materials and fertilizers have already been proposed and put into practical use.However, most of the incinerated ash and incinerated ash are still discarded due to the large amount of incinerated ash and coal ash emitted. That is the fact. As a method of reusing incinerated ash and coal ash for uses other than building materials and fertilizers, see
No. 1-343181 discloses a method for producing a porous molded body from incinerated ash or coal ash and using the same for a microorganism-supporting carrier, an adsorbent, a photocatalyst-supporting body or the like used for fermentation, water treatment and the like. ing.

In this method, as shown in FIG. 6, a powdery material such as coal ash or incinerated ash 51 is mixed with a hardening material 52, a lightening material 53,
A mixing step 55 for adding water 54 and the like, a forming step 56 for forming the mixture into pellets, a curing step 57 for curing and curing the formed pellets, a PH adjusting step 58 for adjusting PH, and a drying step 59 A porous pellet 60 is obtained.

[0005] However, the porous pellets 60 produced by such a method have a problem in that the coal ash and the incinerated ash 51 as raw materials contain harmful organic substances such as dioxin and harmful metals such as heavy metals. There has been a problem that it is necessary to take measures against these harmful substances after use or after reuse.

[0006] Japanese Patent Application Laid-Open No. 2000-245278 discloses that a molded article floating in water containing nutrients for alga is produced from incinerated ash and / or coal ash, and the molded article is floated on the sea surface to culture the algae, and the earth is cultivated. A method for reducing CO _{2 on} a scale is disclosed.

In one embodiment of this method, as shown in FIG. 7, coal ash, incineration ash, sand, ground shell, coal, gypsum,
After removing harmful metals such as heavy metals and harmful organic substances such as dioxins from the inorganic material 61 such as diatomaceous earth, a hardening material 62, a lightening material 63, algae culture nutrient 64, water 65 and the like are added to the inorganic material 61. In addition, they are mixed by a high-speed blade type mixer 66 and the mixture
7 and molded in a curing step 68 at a temperature of 110 ° C.
After curing for 4 hours, hardening, demolding 69, and heat curing 70, it is crushed by a crushing granulator and used as a pellet-shaped algae culture medium 71.

In another embodiment of the method, FIG.
As shown in (1), an algal culture medium having a double tube structure (hollow structure) is produced. In this method, a coaxially provided extruder 81 for two-layer extrusion as shown in FIG. 3A is used, and the extruder 81 is formed through a tubular gap between an outer cylindrical tube 82 and an intermediate cylindrical tube 83. The raw material of the porous layer is extruded from the tubular gap between the intermediate cylindrical tube 83 and the inner cylindrical tube 84, respectively, to form a double tubular molded body.

[0009] As shown in FIG.
Pressed at predetermined intervals and cut at the pressed position 93
A porous outer layer 91 as shown in FIG.
An aqueous inner layer 92 having a central cavity 90 formed therein
A molded body 95 having a hollow structure is manufactured. Shaped like this
The formed porous compact 95 floats on the water surface for a long time.
Play and use solar energy by attaching algae to the surface
CO photosynthesis ₂Is absorbed and fixed on the sea surface on a large scale
Can be made.

In this method, dioxins and heavy metals are previously removed from inorganic materials such as coal ash, incinerated ash, sand, crushed shells, coal, gypsum, and diatomaceous earth. Is not described.

[0011]

As described above, incineration ash and coal ash are conventionally generated in large quantities, and their reuse in building materials, fertilizers, microorganism-carrying carriers, etc. has been studied.
Since incinerated ash and coal ash contain harmful organic substances such as dioxin and harmful metals such as heavy metals, the development of an effective removal method has been required.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and it is an object of the present invention to effectively remove or reduce heavy metals and dioxins to a concentration at which they are harmless, and to make incinerated ash and coal ash an effective resource. An object of the present invention is to provide a method for producing an inorganic porous molded body that can be produced.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for producing an inorganic porous molded body having the following constitution.

That is, in the method for producing an inorganic porous molded body according to the first aspect of the present invention, the incinerated ash and / or the coal ash are heated and melted in an inert gas atmosphere under a condition where harmful organic substances can be decomposed. A melting step of generating a melt from which organic matter has been removed, and injecting the melt into water, suspending the slag component on the water surface as foamed slag and sinking a metal component containing a harmful metal into the water to form a slag component; A separation step of separating a metal component, a pulverization step of pulverizing the foamed slag to a powdery inorganic material, a molding step of molding the powdered inorganic material into a molded article of a predetermined shape, And a curing step of curing by heating.

According to the first aspect of the present invention, dioxins in incinerated ash and coal ash are decomposed and removed at a high temperature that makes the incinerated ash and coal ash in a molten state, while heavy metals are converted into incinerated ash and coal ash. The molten material is poured into water, and the specific gravity difference causes the slag component to float on the water as foamed slag.
When submerged in water, the metal component is separated from the slag component along with other metal components. As a result, harmful components such as heavy metals and dioxins in the slag component are removed or reduced to a harmless concentration.

According to a second aspect of the present invention, there is provided a method for producing an inorganic porous molded body, wherein incinerated ash and / or coal ash are heated and melted in an inert gas atmosphere under a condition under which harmful organic substances can be decomposed and separated. A melting step of generating a melt from which the slag component has been removed, a separation step of separating a slag component from the melt, a pulverization step of pulverizing the slag component into a powdery inorganic material, And a curing step of heating and curing the molded body to solidify it.

According to the method of the present invention, dioxin in the incinerated ash or coal ash is decomposed and removed at a high temperature for converting the incinerated ash or coal ash into a molten state, while the heavy metal is separated from the slag in the molten state. In this case, it remains in the melt and is separated. As a result, harmful components such as heavy metals and dioxins in the slag component are removed or reduced to a harmless concentration.

According to a third aspect of the present invention, there is provided a method for producing an inorganic porous molded body according to any one of the first to second aspects, wherein the incinerated ash and / or coal ash is briquette. It is supplied to the heating step in a form formed into a shape.

According to the method of claim 3, incineration ash and / or
Alternatively, since coal ash is supplied to the heating step in a briquette-shaped form, it can be heated and melted efficiently, handling becomes easy, and deterioration of the working environment is suppressed.

According to a fourth aspect of the present invention, there is provided a method of manufacturing an inorganic porous molded body according to any one of the first to third aspects, wherein the melting step comprises:
Incineration ash and / or coal ash in an inert gas atmosphere,
It is performed by heating at a temperature of 1550 ° C. to 1650 ° C. for 30 minutes or more.

According to the method of the present invention, the incinerated ash and / or coal ash are melted and contained by heating at a temperature of 1550 ° C. to 1650 ° C. for 30 minutes or more in an inert gas atmosphere. Harmful organic substances such as dioxins which have been decomposed and removed or reduced to harmless concentrations.

According to a fifth aspect of the present invention, in the method for producing an inorganic porous molded body according to any one of the first to fourth aspects, prior to the molding step,
A component adjusting step for adjusting components in the powdery inorganic material is provided. According to the method of claim 5, it is possible to obtain an inorganic porous molded body having physical and chemical properties according to the use.

According to a sixth aspect of the present invention, in the method for producing an inorganic porous molded body according to any one of the first to fifth aspects, the powdered inorganic material before molding is: It is characterized by including microbial culture nutrients. According to the method of claim 6, an inorganic porous molded body as a microorganism culture medium can be obtained.

According to a seventh aspect of the present invention, in the method for producing an inorganic porous molded body according to any one of the first to sixth aspects, the nutrient for culturing the microorganism is phosphorus,
It is characterized by comprising a compound containing at least one element of iron and nitrogen.

The phosphorus, iron, nitrogen and the like used in the method of claim 7 are contained in sewage sludge and the like. According to this method, sewage sludge is replenished by treating it with incineration ash and / or coal ash. Therefore, there is also an advantage that a large amount of sewage sludge can be simultaneously treated.

The inorganic porous molded article according to claim 8 is the method according to any one of claims 1 to 7, wherein the powdered inorganic material before molding has a Fe content of 0.1% by weight. Hereinafter, the content of Cr is 0.01% by weight or less, the content of Pb is 0.006% by weight or less, and the content of Zn is 0.00% or less.
It is characterized in that the content of Hg is 6% by weight or less and the content of Hg is 0.0001% by weight or less. According to the present invention, it is possible to produce the inorganic porous molded article having the extremely low content of harmful metals described in claim 8.

According to a ninth aspect of the present invention, in the method according to any one of the first to eighth aspects, the powdery inorganic material before molding has a dioxin content of 0.3 ng / g. It is characterized by the following. According to the present invention, an inorganic porous molded article having a very low content of the harmful organic compound described in claim 9 can be produced.

[0028] According to a tenth aspect of the present invention, in the method according to any one of the first to ninth aspects, the heat curing step is performed at a temperature of 100 ° C or higher. According to this method, an inorganic porous molded body having high compressive strength can be obtained.

[0029]

Next, an embodiment of the method for producing an inorganic porous material of the present invention will be described with reference to FIG. FIG.
1 is a manufacturing process diagram for describing an embodiment of a method for manufacturing an inorganic porous body according to the present invention in the order of steps. Waste such as general waste and industrial waste is incinerated in an incinerator,
The generated incineration ash 1 is used as a raw material for recycling.

At this time, coal ash can be mixed with incineration ash, or only coal ash can be used as a raw material. The incineration ash 1 is an inorganic substance contained in an organic substance or an oxide of a metal component, but also contains a small amount of harmful organic substances such as dioxin generated when the substance is burned at a relatively low temperature.

The incineration ash 1 is degassed in a vacuum in the molding step 2 and is replaced with nitrogen gas.
Is pressed at ^two or more surface pressure is processed into bulk density more briquette molding body (ash). This briquette-like molded body is carried into a melting furnace heated in the next melting step 3 and melted. In the melting step 3, the briquette-like molded body is heated to 1550 to 16 by an electric heater in an atmosphere of an inert gas such as nitrogen gas, helium, neon, or argon.
It is carried into a graphite melting furnace electrically heated to a high temperature of 50 ° C.

The briquette-like molded body carried into the graphite melting furnace is melted by being heated at 1550-1650 ° C. for 30 minutes or more in the furnace, and the slag component floats on the surface of the molten material when poured into a water tank. And the metal component remains as the molten metal 5 in the lower layer of the melt. At this time, the dioxin component 6 in the incineration ash 1 is thermally decomposed 7 and detached from the melt, thereby rendering the melt harmless. The melting step 3 is indicated by a dotted frame 9 in FIG.

In the present invention, the pure white slag 4a as a raw material of the inorganic porous molded body is produced by heating at 1550-1650 ° C. for about 30 minutes to 1 hour.
At the following temperatures, it takes about 5 hours. 1500
The slag 4a formed by injecting into a water tank after heating for a long time at a temperature of not more than 0 ° C. has a large specific gravity and becomes brownish. Conversely 1
Heating at a temperature exceeding 650 ° C. increases the power consumption and increases the cost as a recycling process. For this reason, it is preferable that the superheating in the melting step 3 is performed in a temperature range of 1550 to 1650 ° C.

On the other hand, the metal component contained in the form of oxide in the incineration ash 1 as the starting material is reduced by the carbon component contained in the process of melting the incineration ash in an inert gas atmosphere, and the molten metal 5 And accumulates at the bottom of the graphite melting furnace. Among the metal oxides, silica, alumina and the like, which are oxides of silicon and aluminum, cannot be reduced by carbon, and are therefore contained in the slag.

Further, dioxin contained in the incineration ash 1 as a starting material is 1550 to 1550 in an inert gas atmosphere.
It is thermally decomposed by heating at a high temperature of 1650 ° C. for 30 minutes or more, decomposed and volatilized, and its concentration is reduced to a harmless degree. Considering the effect on the ecosystem, the concentration of dioxin contained in the powdered inorganic material is 0.3 ng /
g or less, but for example, incineration ash is
When held in a 650 ° C. melting furnace for 15 minutes, the concentration of dioxin is reduced to a harmless level of about 0.01 pg / g.

As described above, the incinerated ash 1 is completely melted, and the metal components are reduced and remain at the bottom of the furnace as a melt. After the dioxin reaches a harmless level, the slag 4a is separated from the melt in the separation step 10. And the molten metal 5 are separated. The separation step 10 is performed by injecting incinerated ash obtained by heating and melting a melt for a predetermined time into a large amount of water in a water tank. When the melt is injected into water, the slag 4a is finely broken and the foamed slag 4b having an apparent specific gravity of about 0.1 to 0.2
It floats on the surface of the aquarium. Since the foamed slag 4b does not contain a harmful component and is brittle, it can be easily crushed into fine particles in the crushing step 13.

In this pulverizing step 13, the foamed slag 4b is
The powdered inorganic material 14 is pulverized to a size of 0 μm or more, particularly about several hundred μm. The content of heavy metals in the finely powdered inorganic material 14 thus obtained is 0.1% by weight or less for Fe, 0.01% by weight or less for Cr, and Pb 0.006% by weight or less, Z
0.006% by weight or less for n, 0.0001% by weight for Hg
It is desirable that: With such a content, the fine powdered inorganic material 14 has a legal elution standard of Cr: 0.05 ppm or less, Pb: 0.01 ppm or less, Hg: 0.0005 ppm or less (Fe is no standard).
Can be cleared.

On the other hand, the metal component which has been melted at the bottom of the melt in the melting furnace is rapidly cooled by a large amount of water, becomes small particles, and sinks to the bottom of the water tank. This metal component is usually mostly Fe, and additionally contains Pb, Zn, Cr and the like. The metal component that has settled in the water is a particulate metal 11
, And can be collected and reused 12.

The inorganic porous molded body is manufactured using the pulverized fine powdered inorganic material 14 as follows. First, in the mixing step 15, the fine powdery inorganic material 14
The stirring blade is uniformly mixed with the water 20 at a predetermined ratio using a Henschel mixer, which is a kind of blade type high-speed stirring blade mixer. At this time, other components, for example, cement, gypsum, and lime can be added to the fine powdery inorganic material 14 for the purpose of improving the strength and for other purposes.

Since the incineration ash 1 usually contains a large amount of calcium, the necessary amount of cement, coal, and the like necessary for hydraulicity is to harden sand and other aggregates. Can be less than required. The addition of water brings the finely powdered inorganic material 14 into a wet state.

The finely powdered inorganic material 14 in a wet state
Is transported to the molding step 16 and is inserted into a pellet molding frame and cured to such an extent that its shape is not lost. The cured pellets are sent to the next curing step 17, where they are heated and cured at a temperature of 100 ° C. or more for 1 hour or more and are completely cured.

When the curing temperature is lower than 100 ° C., it is difficult to satisfy the compressive strength of about 5 kg / cm ^2, and it is difficult to form a practicable porous pellet, and conversely, When the curing temperature exceeds 500 ° C., the compressive strength becomes about 10 kg / cm ² , and when the curing temperature exceeds 900 ° C., the compressive strength becomes about 20 kg / cm ² or more. Manufactured.

Since the inorganic porous body 18 thus manufactured is reduced to such an extent that heavy metals and dioxins are removed or made harmless, various kinds of carriers, microorganisms used for fermentation, water treatment, gas treatment and the like are used. It can be used as a support, an adsorbent support, a photocatalyst support, and the like. Specific applications include, for example, yeast carriers for ethanol production, microbial carriers for denitrification from wastewater, adsorbents for deodorization, and the like.

Next, an embodiment of a method for producing a microorganism carrier for denitrification treatment using an inorganic porous molded body will be described with reference to FIG. FIG. 2 is a flowchart for explaining an example of a method for producing a microorganism carrier for denitrification treatment in the order of steps.

In this embodiment, sewage sludge is effectively used as a source of phosphorus and iron as a nutrient for culturing microorganisms to improve affinity with microorganisms. Sewage sludge also contains heavy metals and dioxins. In this case, the sewage sludge is also subjected to the treatment described with reference to FIG. In addition, the addition of only the phosphorus and iron sources as microbial culture nutrients was added separately because the nitrogen source, which is another nutrient, functioned as a type of microbial carrier that absorbs the carrier of the final product from the air. It is not necessary.

Next, a specific description will be given. Note that the same steps as those described with reference to FIG. 1 are denoted by the same reference numerals to avoid duplication, and description thereof will be omitted. In this embodiment, a fine-powder inorganic material 14 generated from incineration ash 1 of general waste is added to a phosphorus / iron source 19 which is a microbial culture nutrient of fine powder generated from incineration ash 21 of sewage sludge, and water 20
Are mixed 15 and formed into a predetermined shape 33 and cured by heating and curing 35 to obtain the target microorganism carrier 36 for denitrification.

First, the step of generating the phosphorus / iron source 19 will be described. In the incineration ash 21 of sewage sludge,
It is put into a mold and pressurized to form briquetted ash. This briquette-like molded body is carried into a melting furnace and a melting step 23 is performed. In the melting step 23, an inert gas atmosphere is formed by an inert gas such as nitrogen gas, helium, neon, or argon, and 1550 by an electric heater.
The briquette shaped body is carried into a graphite melting furnace heated to 〜1650 ° C., and is heated and melted for 30 minutes or more.

In the melting step 29 shown by a dotted frame 29 in FIG. 2, the slag component in the incineration ash 21 floats on the surface of the melt to become pure white slag 24a, and the metal component is Stay at 25. At this time, the metal component contained in the form of oxide in the incineration ash 21 is reduced by the carbon component contained in the process of melting the incineration ash in an inert gas atmosphere to become a molten metal 25, which is used in the graphite melting furnace. Stay at the bottom. Among the metal oxides, silica, alumina and the like, which are oxides of silicon and aluminum, cannot be reduced by carbon, and are therefore contained in the slag.

Further, the dioxin 26 contained in the incineration ash 21 is thermally decomposed 27 and is separated from the melt to detoxify the melt. In the melting step 23, for example, when the melt is kept at a temperature of 1550 to 1650 ° C. for 15 minutes, the concentration of dioxin contained in the foamed slag 24b is reduced to about 0.01 pg / g. The melting step 23 is indicated by a dotted frame 29 in FIG. The concentration of dioxin contained in the foamed slag 24b as a phosphorus / iron source is preferably about 0.3 ng / g or less.

Next, a separation step 30 of the slag 24a and the molten metal 25 is performed. The separation step 30 of the slag 24a and the molten metal 25 is performed by injecting molten ash into a water tank filled with water at normal temperature. The molten ash injected into the water tank has the above-mentioned slag 24a converted into foamed slag 24b.
It floats on the surface of the aquarium.

Thus, the incineration ash 21 is completely melted,
After the metal component is reduced and accumulates at the bottom of the melting furnace as a melt, and the dioxin reaches a harmless level, the slag 24a and the molten metal 25 are separated from the melt in the separation step 30. The separation step 30 is performed by injecting incinerated ash obtained by heating and melting the melt for a predetermined time into a large amount of water in a water tank. When the melt is poured into water, the slag 24a is finely broken into foamed slag 24b having an apparent specific gravity of about 0.1 to 0.2, and floats on the water surface of the water tank.

The foamed slag 24b contains no harmful components and is brittle, so that it can be easily crushed into fine particles in the crushing step 33. In this grinding step 33, the foamed slag 24
b is pulverized to a size of 10 μm or more, particularly about several hundred μm, to obtain a fine powder inorganic material which is a phosphorus / iron source 19 as a microbial culture nutrient. Through the above steps, the phosphorus / iron source 19 as the fine powdery inorganic material is generated from the sewage sludge.

The content of heavy metals in the thus obtained microbial inorganic material 19 as a phosphorus / iron source is 0.1% by weight or less in Fe and C
r 0.01% by weight or less, Pb 0.006% by weight or less, Zn 0.006% by weight or less, Hg 0.0001% by weight
It is desirable that the content be not more than weight%.

Next, the phosphorus / iron source 19, the finely divided inorganic material 14, and the water 20 were mixed by a Henschel mixer or the like.
5 to obtain a wet mixture. This mixture is used in the molding step 34, for example, in the extruder 8 described in FIG.
It is molded into a hollow structure using 1 or the like.

In the curing step 35, the molded article having a hollow structure is formed.
The microbial carrier 36 for denitrification treatment having a hollow structure is obtained by heating and curing at a temperature of 100 ° C. or higher. The microbial carrier for denitrification treatment 36 having the hollow structure can be manufactured by, for example, the method described with reference to FIG.

When the incineration ash 1 is mainly used, for example, 100 parts by weight of the fine powdery inorganic material 14 is used as the material of the outer layer.
10 parts by weight of phosphorus / iron source 19 from which harmful components have been removed from sewage sludge incineration ash 21 and 80 parts by weight of water 20 are mixed with a mixer at 10 parts by weight.
For example, as a material for the inner layer, 100 parts by weight of the fine powdery inorganic material 14 and water 2
0 and 80 parts by weight can be used in a mixer for 10 minutes.

When coal ash is used, for example, as the outer layer material, 60 parts by weight of the fine powdered inorganic material 14 from which harmful components have been removed from coal ash, 40 parts by weight of lime, and sewage sludge incineration ash 21 Phosphorus and iron source 19 with harmful components removed
Can be used by mixing 10 parts by weight of water and water 20 with a mixer for 15 minutes. As a material of the inner layer, 60 parts by weight of the fine powdery inorganic material 14, 40 parts by weight of lime and water 20 are mixed with a mixer. Mixtures mixed for 15 minutes can be used.

In each case, the size of the final molded product is approximately 1c.
m is preferable, and the shape is not limited. The microorganism carrier for denitrification treatment 36 obtained by curing for 1 hour in a heating atmosphere at 900 ° C.
Has a compressive strength of about 20 kg / cm ² .

The results of measurement of the ability to remove nitrate ions when the denitrifying bacteria are carried on the thus-produced microbial carrier 36 for denitrification are as follows.

An aqueous solution for measurement was prepared in the flask so that methanol and sodium nitrate were adjusted to have a concentration of 100 ppm and a concentration of 100 ppm with respect to about 1 liter of tap water. One microbial carrier for denitrification treatment 36 carrying denitrifying bacteria was charged into this aqueous solution for measurement. The microorganism carrier 36 for denitrification is a porous pellet having a size of about 1 cm3.

FIG. 3 is a characteristic curve diagram showing a comparison between the conventional example using the porous pellets of the microbial carrier 36 for denitrification treatment and activated carbon and the nitrate ion removal ability of this example, and 5 days. FIG. 4 shows a change in nitrate ion concentration when immersed in the aqueous solution. 3 shows the results using the denitrification treatment microbial carrier 36 of the example, and the x marks show the denitrifying bacteria in the same measurement aqueous solution for comparison. This is the result when one activated carbon was loaded and left in this state for 5 days.

As is apparent from the results shown in FIG. 3, the porous pellets of the microbial carrier 36 for denitrification showed a superior microbial activity than the activated carbon carrier. That is, it is understood that the denitrifying bacteria are effectively acting on the nitrate ions. Furthermore, since the above-mentioned embodiment uses sewage sludge having affinity for microorganisms as the phosphorus / iron source 19 of the microbial culture nutrients, it also contributes to effective utilization of sewage sludge.

Next, an embodiment of an algal culture method using an inorganic porous molded body will be described with reference to FIG. FIG.
It is a flowchart for demonstrating the example of the algae culture method using an inorganic porous molded object in a process order. In this embodiment, microalgae are cultured on a large scale in the ocean, and carbon dioxide (CO2) on the earth is obtained by photosynthesis using solar energy.
_This is a case where an algal culture medium for fixing ₂ ) is manufactured.

Next, a method for producing an algal culture medium for culturing microalgae will be specifically described. The description of the same steps as those in FIGS. 1 and 2 will be repeated, and thus the same reference numerals will be given and the description thereof will be omitted. The feature of this embodiment is that a phosphorus / iron source and a nitrogen source are supported on an algal culture medium as nutrients for microalgae.

Fine powdered inorganic material 14 is generated from incinerated ash 1 such as general waste and industrial waste, and fine powdered inorganic material is generated from incinerated ash 21 of sewage sludge as a phosphorus / iron source 19 for algae culture nutrients. Is done. In the mixing step 15, phosphorus
Algae culture nutrient 4 consisting of iron source 19 and sodium nitrate 39
0, water 20 is mixed by a Hensyl mixer to obtain a wet mixture. Further, the fine powdered inorganic material 1
4. Water 20, cement and the like as a hardener are mixed by a Henschel mixer to obtain a wet mixture.

This mixture is used in a molding step 41, for example, as shown in FIG.
Is formed into a hollow structure by the extruder 81 described in the above. The outer layer can be formed using a mixture of the finely powdered inorganic material 14, the phosphorus / iron source 19, sodium nitrate 39, and water 20, and the inner layer is formed using a mixture of the finely powdered inorganic material 14, water 20, and cement. Can be formed. The inner layer forms a waterproof layer.

The porous molded body formed into a hollow structure in this manner is cured in a curing step 42 at a temperature below the melting point and at a temperature above 100 ° C. to obtain a porous molded body having a hollow structure. Can be Thus, the pellet-shaped algae culture medium 43 containing the algae culture nutrients in the outer layer is manufactured. The reason why the hollow structure is used is that the hollow structure is used by floating on the water surface.

Next, a specific example of the production of the algae culture medium 43 will be described. When the incineration ash 1 is mainly used, the outer layer is composed of 100 parts by weight of the powdered inorganic material 14 from which the harmful substances have been removed from the incineration ash 61 and 10 phosphorus / iron sources 19 from which the harmful substances have been removed from the sewage sludge incineration ash 21. The mixture was formed by mixing 20 parts by weight of sodium nitrate 39 and 80 parts by weight of water 20 with a mixer.

The inner layer was formed of a mixture obtained by mixing 50 parts by weight of the powdered inorganic material 14, 50 parts by weight of cement and 80 parts by weight of water 20 with a mixer. This inner layer is provided with a waterproof effect in order to float up for a long time.

The inner layer had a hollow inside, and was formed into a hollow structure having a size of about 1 cm in diameter and about 1 cm in length. This molded body has a temperature of 900 ° C. below the melting point.
The compressive strength of the pelleted algae culture medium 43 produced by heating and curing in a heating atmosphere for 1 hour is about 20 kg / cm.
It was ² .

When coal ash is used instead of incineration ash 1, the outer layer is composed of 60 parts by weight of powdered inorganic material 14 from which harmful substances have been removed from coal ash, 40 parts by weight of lime, and sewage sludge incineration ash 21. Phosphorus and iron source 19 from which harmful substances have been removed
0 parts by weight, 20 parts by weight of sodium nitrate 39 and water 2
0 was formed by a mixture obtained by mixing 80 parts by weight with a mixer.

The inner layer is formed of a mixture obtained by mixing 60 parts by weight of the powdered inorganic material 14 obtained by removing harmful substances from coal ash, 40 parts by weight of lime, 50 parts by weight of cement and 80 parts by weight of water 20 by a mixer. did. This inner layer has a waterproof effect. The inner layer was formed into a hollow structure having a cavity.

The size of the compact was about 1 cm in diameter and about 1 cm in length. This molded product is subjected to 9
The compressive strength of the pellet-shaped algae culture medium 43 using the inorganic porous molded body obtained by curing for 1 hour in a heating atmosphere of 00 ° C. was about 30 kg / cm ² .

The reason why the compressive strength of the algae culture medium 43 manufactured from coal ash was higher than the compressive strength of the algae culture medium 43 manufactured from the incinerated ash 1 is that the algae culture medium 43 manufactured from the coal ash has a higher compressive strength. This is considered to be an effect because the molded body 91 contains lime as a hardening material. These compressive strengths are strengths (about 5 k) for use as a porous body.
g / cm2).

In this embodiment, when culturing microalgae with enhanced nitrogen fixing ability in the algae culture medium 43, the amount of sodium nitrate 39 to be carried can be reduced or eliminated. FIG. 5 shows the algal growth ability of microalgae culture pellets according to the present invention (marked by ○) and the algal growth ability of pellets (comparative pellets) produced from coal ash (60 parts by weight) and lime (40 parts by weight) as inorganic materials (×). FIG. 4 is a characteristic curve diagram showing a comparison between the graphs.

In this growth test, one pellet according to the present invention was placed in about 1 liter of artificial seawater in a flask and cultured under a fluorescent lamp for 20 days. The characteristics in FIG. 5 show the change over time in the microalgal concentration during this algal culture process. For comparison, as the inorganic material, coal ash 60 parts by weight, coal 40
Comparative pellets were prepared using parts by weight and tested under the same conditions. FIG. 5 shows that the growth ability of the microalgae culture pellet according to the present invention was about 1.5 times that of the comparative pellet.
It can be seen that it has twice the proliferation ability.

The algae culture medium 4 thus produced
No. 3 is produced as a raw material of the powdered inorganic material 14 from which harmful components have been removed or made harmless, and thus is effective as a medium for culturing microalgae. By spraying a large amount of the algal culture medium 43 into the ocean, the algal culture medium 43
Floats on the sea surface for a long time, and this algae culture medium 43 contains
Marine microalgae are cultured.

Since the algae culture medium 43 contains the nutrients of the algae, the microalgae grow efficiently. During this growth process, the algae cultured in the algae culture medium 43 fix a large amount of CO ₂ by photosynthesis using solar energy, and are effective in mitigating the global warming phenomenon. Algae can contribute to the supply of fossil fuel alternative energy because it is a raw material for useful substances such as ethanol.

In the above embodiment, the means for separating the foamed slag and the molten metal from the molten ash has been described as a means for injecting into water, but may be any liquid as long as it is liquid.

In the above-described embodiment, an example in which incinerated ash of sewage sludge is used as a phosphorus / iron source has been described. However, as long as it has a phosphorus / iron component as a culture nutrient for microorganisms, any may be used, for example, phosphate glass. May be used.

[0081]

According to the present invention, an inorganic porous material made of an inorganic material obtained by removing harmful components from at least one of a large amount of incinerated ash, coal ash, and sewage sludge or reducing the concentration to a harmless concentration. Can be manufactured.

Furthermore, by supporting nutrients for algae culture on this inorganic porous body, a nutrient supply medium for algae culture using an inorganic porous molded body that can be suspended in the ocean or water can be manufactured. By supporting nutrients for algae culture and denitrifying bacteria on this inorganic porous material, it is effective for denitrification from sewage, gasoline, petroleum and the like.

Further, it is possible to produce an inorganic porous body made of an inorganic material obtained by removing harmful components from incinerated ash, coal ash and sewage sludge discarded in a large amount or reducing the concentration to a harmless concentration. It can be recycled as an adsorbent used for removing harmful substances, and as a carrier for immobilizing microorganisms used for sewage treatment, fermentation, soil recovery, and the like.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining an embodiment of a manufacturing method of the present invention in the order of manufacturing steps.

FIG. 2 is a flowchart for explaining another manufacturing method of FIG. 1 in the order of steps.

FIG. 3 is a characteristic curve diagram showing a change in nitrate ion concentration when a denitrification treatment microorganism carrier carrying the denitrification bacteria of FIG. 2 and a microorganism carrier of a comparative example are respectively placed in an aqueous solution for measurement.

FIG. 4 is a flowchart for explaining another manufacturing method of FIG. 2 in the order of steps.

FIG. 5 is a characteristic curve diagram showing a change in the concentration of microalgae when the microalgae are cultured by placing the algal culture medium of FIG. 4 and the algal culture medium of the comparative example in seawater for measurement, respectively.

FIG. 6 is a flowchart for explaining a conventional method for producing a porous pellet.

FIG. 7 is a flowchart for explaining a conventional method for producing an algal culture medium.

FIG. 8 is a view for explaining a method of manufacturing the pellet having the cavity of FIG. 7;

[Explanation of symbols]

1 ... incineration ash, 2, 16, 34, 41 ... molding process, 3, 2
3 ... melting process, 4a, 24a ... slag, 4b, 24b ...
Foamed slag, 5,25 ... molten metal, 6,26 ... dioxin component, 7,27 ... pyrolysis, 10,30 ... separation process,
11, 31: metal, 13, 33: pulverizing step, 14: fine powdered inorganic material, 15: mixing step, 17, 35, 42 ... curing step, 18: inorganic porous molded body, 19: phosphorus / iron source,
20 ... water, 21 ... incineration ash of sewage sludge, 36 ... microbial carrier for denitrification treatment, 43 ... algae culture nutrient, 39 ... sodium nitrate.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C12N 1/00 A01G 33/00 1/12 B09B 3/00 ZAB 11/14 303L // A01G 33/00 5 / 00 N (72) Inventor Hiroshi Ohata 6-15-1, Ginza, Chuo-ku, Tokyo Inside Power Development Co., Ltd. (72) Inventor Hideyuki Yanagita 6-15-1, Ginza, Chuo-ku, Tokyo Stock of power development In-company (72) Inventor Hideo Higuchi 267-1-1, Tana, Sagamihara-shi, Kanagawa Prefecture Inside Higuchi Works Co., Ltd. Inventor Yu Okamoto 1-1-1 Shibaura, Minato-ku, Tokyo F-term in the head office of Toshiba Corporation (Reference) 2B026 AA05 AC01 4B033 NA11 NB02 NB22 NB68 NF06 NG01 NH04 4B065 AA83 X BB03 BB11 BB12 BC42 CA54 4D003 AA05 EA15 EA19 EA22 EA28 EA38 4D004 AA36 AB03 AB07 BA05 BA10 CA04 CA10 CA14 CA15 CA29 CA45 CB05 CC03 CC11 CC13 DA03 DA06

Claims (10)

[Claims] 1. A melting step of heating and melting incinerated ash and / or coal ash in an inert gas atmosphere under conditions under which harmful organic substances can be decomposed to produce a melt from which harmful organic substances have been removed; Injecting the melt into water, suspending the slag component on the water surface as a foamed slag and sinking a metal component containing a harmful metal into water to separate the slag component and the metal component, and separating the foamed slag. A pulverizing step of pulverizing the powdered inorganic material into a powdered inorganic material; a forming step of forming the powdered inorganic material into a formed body having a predetermined shape; and a curing step of heating and curing the formed body to be solidified. A method for producing an inorganic porous molded body, comprising: 2. A melting step of heating and melting incinerated ash and / or coal ash in an inert gas atmosphere under a condition under which harmful organic substances can be decomposed and separated, thereby producing a melt from which harmful organic substances have been removed. A separation step of separating a slag component from the melt, a pulverizing step of pulverizing the slag component into a powdered inorganic material, and a forming step of forming the powdered inorganic material into a molded body having a predetermined shape, And a curing step of heating and curing the molded body to solidify the molded body. 3. The method for producing an inorganic porous formed body according to claim 1, wherein the incinerated ash and / or coal ash are supplied to the heating step in a briquette-shaped form. 4. The melting step includes the steps of: burning incinerated ash and / or coal ash in an inert gas atmosphere at 1550 ° C. to 1650 ° C.
The method for producing an inorganic porous molded body according to any one of claims 1 to 3, wherein the method is performed by heating at a temperature of 30 ° C for 30 minutes or more. 5. The inorganic porous molded body according to claim 1, further comprising a component adjusting step of adjusting a component in the powdered inorganic material prior to the forming step. Manufacturing method. 6. The method for producing an inorganic porous molded body according to claim 1, wherein the powdered inorganic material before molding contains nutrients for culturing microorganisms. 7. The inorganic porous material according to claim 1, wherein the microorganism culture nutrient comprises a compound containing at least one element among phosphorus, iron, and nitrogen. How to make the body. 8. The powdered inorganic material before molding has an Fe content of 0.1% by weight or less, a Cr content of 0.01% by weight or less, and a Pb content of 0.006% by weight or less. , Zn
Is 0.006% by weight or less, and the Hg content is 0.1% by weight.
The method for producing an inorganic porous molded body according to any one of claims 1 to 7, wherein the content is 0001% by weight or less. 9. The inorganic porous material according to claim 1, wherein the powdered inorganic material before molding has a dioxin content of 0.3 ng / g or less. How to make the body. 10. The method for producing an inorganic porous molded body according to claim 1, wherein the heat curing step is performed at a temperature of 100 ° C. or higher.