JPH11171661A - Foam material using burnt ash slag glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a foam material having a stable amount of foaming by mixing a ground material prepared by vitrifying burnt ash of refuse with clay, adding an alkali component to the mixture and baking. SOLUTION: A slag glass has 74-1,500 μm particle diameter. The composition and qualities of clay to be used hardly exert influence on foamability. A sodium- containing compound (e.g. sodium carbonate), practically soda ash is used as the alkali component. The amount of the alkali component used is 0.5-10.0 wt.% based on the slag glass. After the slag glass is mixed with clay and the alkali component, the mixture is blended with water. The amount of water added is 10.0-20.0 wt.% based on the total amount. The mixture is fed to a mold frame and baked in a baking furnace. Preferably the rate of temperature rise is 10-20C/minute, the maximum baking temperature is 950-1,050 deg.C and the rate of temperature drop is 5-50 deg.C. The expansion ratio of 2.0-3.9 times is obtained by adding 3.0-5.0 wt.% of soda ash to the slag glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to incineration ash (hereinafter referred to as "incineration ash") generated in large quantities by incineration of sewage sludge and municipal waste.
Called. The present invention relates to a foamed material obtained by effectively utilizing slag glass obtained by vitrifying ()).

[0002]

2. Description of the Related Art Waste incineration ash is generated in large quantities in many cities and is generally disposed of by burying it in the ground. ing. In addition, the effective use and reuse of resources,
Alternatively, in order to prevent environmental pollution, it is necessary to reduce the absolute amount of these incineration ash.

[0003] Conventionally, in order to reuse refuse incineration ash, reduction and melting of refuse incineration ash to form slag glass has been promoted, and a foamed material that can be effectively used as a building material or the like is produced from pulverized slag glass. Attempts have been made.

That is, a slag glass pulverized material produced from refuse incineration ash is mixed with clay and, if necessary, an additive for promoting foaming, and water is added and kneaded. When firing in the temperature range of above, foaming starts in the firing process due to the release of gaseous substances and gas components involved in the oxidation-reduction reaction, and also the promotion of softening of the glass phase under high temperature conditions, and as the temperature rises The amount of leverage increases sharply and a foam is obtained. This foamed material is useful as a lightweight soundproofing material, a heat insulating material and the like utilizing the cell structure.

[0005]

However, when the mixture of the slag glass pulverized material and the clay is fired and foamed as described above, the foaming amount varies greatly depending on the case, and the desired foaming amount, that is, the desired specific gravity, is obtained. Further, there is a problem that a foamed material having a porosity cannot be stably manufactured.

[0006] This is because the composition of sludge and municipal garbage, which are the raw materials of slag glass, is not constant, and the composition of slag glass also varies greatly depending on the place and time of generation. And the temperature range of softening of the glass greatly differ, and the timing of softening of the glass after foaming is shifted.

For this reason, a foamed material having a good foaming property can provide a foamed material having a volume twice or more as large as the volume before firing, but a foaming material having an expansion ratio of 1.5 times or less that before firing is extremely small. In many cases, the desired foamed material cannot be industrially produced stably.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a foamed material having a stable foaming amount.

[0009]

The foamed material using the incinerated ash slag glass of the present invention is obtained by mixing a slag glass pulverized product obtained by vitrifying garbage incinerated ash with clay, and firing the obtained mixture. The foamed material obtained by adding an alkali component to the mixture.

[0010] The foaming reaction mechanism by firing a mixture of slag glass and clay is as follows.

Slag glass produced from refuse incineration ash contains a large amount of fine particles made of iron oxide (FeO) in the produced glass, basically for melting in a reduced state.

When such a material is heated, the reaction of 2FeO → 2Fe + O ₂ is promoted at a high temperature (Fe dissolves in the glass at a higher temperature), and oxygen gas surrounds the fine particles inside the glass. Many bubbles are formed.

[0013] Slag glass begins to soften in a high temperature state of 850 ° C or higher, and its viscosity rapidly decreases as the temperature rises. Therefore, the size of these bubbles increases rapidly as the viscosity of the glass decreases. I do. When the temperature reaches the temperature range of 950 to 1050 ° C., the viscosity of the glass rapidly decreases, so that the bubbles expand and become continuous bubbles (space).

Under such high temperature conditions, the mixed clay forms metakaolin by a dehydration reaction at several hundred degrees centigrade, but under higher temperature conditions, it reacts with the slag glass phase to produce wollastonite (CaSiO ₃ ) And quasi-feldspar (CaAlS
i ₂ O ₇ ) or anorthite (CaAl ₂ Si ₂ O ₈ ).

These form a continuous bubble wall,
Further forming a three-dimensional network structure, these skeletons maintain the strength of the final product and add functions to the product.

Then, up to this stage, a foam is formed in which continuous bubbles are present with an equal particle size distribution.

From the above, the composition of the slag glass has a great influence on the foaming reaction. Conventionally, it has not been possible to obtain a foamed material having a stable foaming amount.

On the other hand, by blending an alkali component according to the present invention, the foaming amount can be significantly increased and the foaming amount can be stabilized.

That is, for example, soda ash can promote the increase of the sodium component in the foaming raw material, greatly reduce the viscosity of the slag glass under high temperature conditions, and at a constant temperature of 800 ° C. or more, soda ash The softening of the glass can be greatly advanced as compared with the case where no additive is added.
For this reason, the bubbles generated in the process of sintering at 800 ° C. or higher cause a rapid expansion around 900 ° C. due to the softening of the glass phase, and eventually form an aggregate of open cells in which single cells are connected, A foam with a high foaming amount is formed.

As the alkali component, a compound containing sodium carbonate (Na ₂ CO ₃ ), practically a sodium-containing compound such as soda ash, is preferably used. , In particular 3.0 to 10.0% by weight, especially 3.0 to 5.0% by weight, in a total ratio of clay to ground slag glass of 15.
It is preferable to add so as to be 0 to 30.0% by weight.

The firing is performed at a maximum temperature of 950 to 1050.
It is preferable to carry out at a temperature of ° C.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail according to a production procedure of a foamed material of the present invention.
The following production method is an example of the method for producing a foamed material of the present invention, and the foamed material of the present invention is not limited to those produced by any of the following production methods.

In order to produce the foamed material of the present invention, first, slag glass is pulverized, and a slag glass pulverized product (hereinafter sometimes simply referred to as “slag glass”) is mixed with clay.

The slag glass used in the present invention is produced by reduction melting of refuse incineration ash, and this slag glass is used after being ground to a particle size of 1.5 mm or less.
If the crushed particle size of the slag glass is too large, the mixing workability is poor, and it is difficult to obtain a uniform mixture of the foaming raw materials,
If the particle size of the slag glass is excessively small, the foaming property deteriorates. Generally, the particle size range of the raw slag glass is from 74 to 1
It is preferably 500 μm, particularly preferably 250 to 1500 μm.

The clay mixed with the slag glass is not particularly limited. That is, in the present invention, since the composition and quality of the clay used have almost no effect on the foaming property, any clay can be used under the same conditions.

The mixing ratio of the clay is such that the total weight of the alkali component and the clay described later is 15.0 to slag glass.
The amount is preferably 30.0% by weight. If the proportion of the clay is less than the above range, the strength required for the foamed material cannot be obtained, and if it is too large, a foamed material having a large foaming amount cannot be obtained.

Next, an alkaline component is added to the mixture of the slag glass and the clay, and the mixture is sufficiently stirred and mixed.

In the present invention, the alkali component added for stabilizing the foaming amount includes a compound containing sodium, preferably sodium carbonate, and practically soda ash.

If the amount of the alkali component is too large, the alkali component is precipitated around the foamed material after firing, and the amount of clay added is relatively reduced, so that the strength required for the foamed material can be obtained. It will be difficult. Conversely, if the added amount of the alkali component is small, the effect of improving foamability cannot be obtained.
Therefore, an alkali component such as soda ash is added in a range of 0.5 to 10.0% by weight, particularly 3.0 to 10.0% by weight, particularly 3.0 to 5.0% by weight based on the slag glass. Is preferred.

It should be noted that the present invention is characterized in that the same foaming amount can be obtained with a uniform blend of raw materials regardless of the type of slag glass, that is, whether or not foamability is good.
The addition amount of the soda ash can be made substantially constant regardless of the type of slag glass used.

After mixing alkali components such as slag glass, clay and soda ash, water is added to the mixture and kneaded. Generally, the amount of water added is 1 to the weight of the mixture of alkali components such as slag glass, clay and soda ash.
It is about 0.0 to 20.0% by weight.

Next, the kneaded material is cast into a mold having an appropriate size, molded and then fired in a firing furnace. In this molding, the type, material, shape, pressure at the time of molding and the like of the mold do not greatly affect the foaming property, and therefore, arbitrary conditions can be adopted. As the firing conditions, the rate of temperature rise is preferably determined in consideration of the composition and production efficiency of the slag glass used, from the viewpoint of promoting the softening of the glass and promoting simultaneous foaming, Usually, 10 to 20 ° C./min is preferable. Further, the maximum firing temperature is preferably 950 to 1050C. If the temperature is lower than 950 ° C., the foaming does not sufficiently proceed. If the temperature exceeds 1050 ° C., high-temperature oxidation occurs to change the color to brown and the foaming material itself starts to soften. Further, in order to prevent cooling cracks after firing, it is preferable to perform cooling after firing at a temperature lowering rate of about 5 to 50 ° C./min so as not to rapidly cool. The firing furnace to be used is not particularly limited as long as it can be fired under the above firing conditions. The heating method may be either electric or gas.

The foamed material using the slag glass of the present invention thus obtained is generally about 3.0 to 5.0% by weight of soda slag glass, regardless of the type of slag glass. By adding ash, a foaming ratio of 2.0 to 3.9 times (ratio of the volume after firing to the volume before firing) can be stably obtained, so that a practical foam material can be easily produced in industrial production. It is possible to do.

[0034]

The present invention will be described below more specifically with reference to experimental examples, examples and comparative examples.

EXPERIMENTAL EXAMPLE 1 Using slag glass evaluated as having poor foaming properties,
The relationship between particle size and foamability was investigated.

First, slag glass having a particle size distribution shown in Table 1 was used, slag glass and clay (Kibushi clay) were mixed at the ratio shown in Table 1, and soda ash was further added thereto. And kneaded with water. The kneaded product was put into a mold and molded, and then fired in a firing furnace at a heating rate of 10 ° C./minute, a high-temperature firing temperature of 950 ° C. for 15 minutes, and a cooling rate of 10 ° C./minute.

The expansion ratio of the obtained foamed material was examined, and the results are shown in Table 1.

From Table 1, it can be seen that foaming properties of slag glass are poor if there are many fine particles, and it is preferable to classify the fine particles in order to obtain a foamed material having a high expansion ratio.

[0039]

[Table 1]

Examples 1 to 7, Comparative Example 1 The same slag glass as used in Experimental Example 1 (particle size range 50
0 μm or less) and clay, and a foamed material was produced in the same manner as in Experimental Example 1 except that the soda ash was added in the proportions shown in Table 2 so as to obtain the soda ash addition rate in Table 2, and the expansion ratio was examined. The results are shown in Table 2.

Table 2 shows that the addition of soda ash significantly increases the expansion ratio and stabilizes the expansion amount. Also, when considering the improvement of the expansion ratio and the cost of adding soda ash, it is understood that the amount of soda ash is preferably 3.0 to 10.0% by weight based on the slag glass.

[0042]

[Table 2]

Example 8, Comparative Example 2 Slag glasses A to D having different compositions (particle size range 500 μm)
The following examples were used to mix soda ash in the following formulation I (the soda ash addition ratio to the slag glass was 3% by weight), and in the comparative example where no soda ash was added, the following blend II was used. A foamed material was manufactured in the same manner as in Experimental Example 1 except that the above procedure was performed.

[0044] The expansion ratio of the obtained foamed material was examined, and the results are shown in Table 3.

[0045]

[Table 3]

From Table 3, it can be seen that the addition of soda ash can stabilize the expansion ratio in the range of 3 to 4 times evenly with all slag glasses.

[0047]

As described above in detail, according to the present invention, uniform continuous cells are obtained from slag glass of incinerated ash of sludge or municipal garbage whose composition and conditions vary greatly, and the foaming amount is stable. A material can be obtained, and thereby, the volume of waste can be reduced and effective reuse can be achieved.

The foamed material of the present invention can be used as a sound absorbing material having a soundproofing effect by easily adjusting the size of cells.
Alternatively, it is very useful for a wide range of uses as a heat insulating material, a building material or a building material for home or industrial use, a filler, and the like.

Claims (7)

[Claims] 1. A foam obtained by mixing crushed slag glass obtained by vitrifying garbage incineration ash with clay and firing the obtained mixture, wherein an alkali component is added to the mixture. A foam material using incinerated ash slag glass. 2. A foamed material using incinerated ash slag glass according to claim 1, wherein said alkali component is a compound containing sodium. 3. The foamed material using incinerated ash slag glass according to claim 2, wherein said alkali component is sodium carbonate. 4. The incinerated ash slag glass according to claim 1, wherein the alkali component is added in an amount of 0.5 to 10.0% by weight based on the slag glass pulverized material. Foam material. 5. The slag glass according to claim 1, wherein a total ratio of the alkali component and the clay to the ground slag glass is 15.0 to 30.0% by weight. Foam using incinerated ash slag glass. 6. The foamed material using incinerated ash slag glass according to any one of claims 1 to 5, wherein the foamed material is fired at a maximum temperature of 950 to 1050 ° C. 7. The foamed material using incinerated ash slag glass according to claim 1, wherein an expansion ratio represented by a volume after firing with respect to a volume before firing is 2 times or more. .