JP2796243B2 - Manufacturing method of incinerated ash sintered body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a chemically stable sintered body by using incinerated ash produced by treating sewage sludge and municipal waste, and more particularly to a method for producing a tile, a floor plate and the like. An object of the present invention is to obtain a sintered body that can be used for various materials such as road pavement materials and building interior and exterior materials requiring high strength.

[0002]

2. Description of the Related Art Sewage sludge and municipal waste, which have been inevitably generated in large quantities in the past, are incinerated in waste incineration plants and the like, and incinerated ash is generated as a residue. Instead of ocean dumping, effective recycling is being pursued.

In general the composition of the ash is a major component weight%, SiO ₂ is 20 to 45, Al ₂ O ₃ is 5 to 17, CaO is 5 to
40, Fe ₂ O ₃ is 5~15, P ₂ O ₅ is 0 to 20, MgO is 0-7
Occurs in the range of The melting temperature of the incinerated ash is 1
It is a high-temperature substance of 300 to 1500 ° C and contains P ₂ O ₅ , so it is highly corrosive, easily becomes alkaline in constitution, is chemically unstable, and is a waste material of sewage sludge and municipal waste. The composition of the incinerated ash is not constant due to the difference in the source and the treatment system.

At present, as a method of recycling incinerated ash, incinerated ash is again heated and melted at 1300 to 1500 ° C. to produce glass ceramics or crushed stone by casting. 2. Description of the Related Art A ceramic product such as a brick or a tile is manufactured by adding materials and firing by a press or the like.

[0005] However, the method of remelting incinerated ash requires a special melting furnace due to the erosion property of the molten material due to the alkali component and P ₂ O ₅ , and the operating conditions due to fluctuations in the composition of the incinerated ash. However, the product characteristics were not uniform, and the product characteristics were inhomogeneous, and in particular, lacked chemical stability.

[0006] In addition, in the method of forming and burning bricks and tiles by adding incineration ash alone or plasticizer, the incineration ash component Ca
High melting point materials such as O, SiO ₂ , and Al ₂ O ₃ increase the firing temperature.When adding a clay-based plasticizer, firing at a high temperature and for a long time is necessary to obtain a homogeneous solid solution sintered body. There are drawbacks that are necessary, and in any case, the fluctuation of the incineration ash composition complicates the management of the firing process, and the product characteristics are not stable. there were.

In the sintering of a compact containing incinerated ash, the incinerated ash is a high melting point powder that has undergone thermal history, and its melting characteristics are mainly determined by a three-component system of SiO ₂ -CaO-Al ₂ O ₃ . For example, those indicating the lowest melting point 1300 ° C is SiO ₂ is 4
1.5%, CaO is 41.5%, Al ₂ O ₃ is 17%. In this component system, the particle surface is melted from around 1150 to 1200 ° C., but the viscosity is large, and the fusion, that is, the progress of sintering is small. In order to efficiently incinerate the incineration ash, a mechanism of a consolidation reaction in which a low-viscosity glass melt is generated between particles at the lowest possible temperature and solid-dissolved with each other to integrate the particles is necessary.

[0008] Conventionally, a method using a medium solvent has been adopted for sintering a high melting point substance. For example, Si
O ₂ -Al ₂ O ₃ ceramics and refractories are made of K ₂ O-Na ₂ O-SiO ₂ mineral feldspars (plagioclase K ₂ O-Al ₂ O ₃ -6SiO ₂ , mp1300 ° C, albite) Na ₂
O-Al ₂ O ₃ -6SiO ₂ , mp 1118 ° C, solid former feldspar and feldspar Li ₂ O-Al ₂ O ₃ -6SiO ₂ , mp 1350 ° C) are used. However, these feldspars are converted into CaO / SiO ₂ like incineration ash.
It was found that the following problems were encountered when used as a systemic substance.

[0009] That is, the melting temperature is high and the firing is required at a temperature of 1250 ° C or more for a long time, and the melt viscosity of feldspar is high and the permeability of the melt between the incinerated ash particles is poor (K-feldspar 1).
000 @ C-7400 × 10 ⁷ poise, albite 1100 @ C-1200 × 10 ⁷ poise). Furthermore, the amount of solid solution of the incinerated ash is small, and the effect of dissolving the medium is small. Therefore, when feldspars are used, the porosity is 2% when the blending amount is 20% by weight or more.
Firing at 1200 to 1300 ° C. for 4 hours or more was required to obtain the following sintered body, which was unsuitable for low-temperature easy firing in connection with fluctuations in the incineration ash composition.

[0010]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a reaction which promotes a sintering reaction of a specific silicate or a medium-soluble component obtained by adding a viscosity modifier to a Na ₂ O—SiO ₂ blend and a total component. Developing a sintering accelerator that combines material components to simplify the management of the sintering process as low-temperature easy sintering of incinerated ash containing a high melting point substance, An object of the present invention is to provide a method for producing an incinerated ash sintered body capable of obtaining a stabilized product.

[0011]

For this reason, the present invention relates to a method for producing a mixture of 100 parts by weight of incinerated ash and a weight ratio of (SiO ₂ + Al ₂ O ₃ ) / Na _2.
Silicate or silicate having O of 9.0 to 1.0 and Na ₂ O
5 to 30 parts by weight of the mixture of the substance
If necessary, a small amount of organic binder or 25 parts of clay plasticizer
A mixture containing not more than parts by weight is molded, and 900 to 115
This is a method for producing an incinerated ash sintered body that is sintered at 0 ° C. It is also possible to use a mixture of 100 parts by weight of incinerated ash and 5 parts by weight or less of BaO or B ₂ O ₃ as a medium solubilizing agent. O
H), F, Cl and a substance that volatilizes B ₂ O ₃
It is good also as a blend which added less than weight part.

Here, the weight ratio of (SiO ₂ + Al ₂ O ₃ ) / Na ₂ O
Is mixed with the incinerated ash using a silicate or a silicate having a pH of 9.0 to 1.0 and a Na ₂ O substance as a solvent medium, because a glass melt is formed at a low temperature, and This is because it is suitable for solid solution and integration. Alkali components K ₂ O and Na ₂ O
The reason why Na ₂ O is used is that K ₂ O has a small amount of silicate solid solution and viscosity is high, whereas Na ₂ O has a silicate solid solution amount of 7 times or more than K ₂ O. is there. Those in which Na ₂ O is within a predetermined ratio may be used as they are. Furthermore, Na ₂ O and Si
O ₂ may be directly mixed and synthesized. In this case, the mixture is reduced to 900 to 1100 to reduce the melting temperature during use.
The material calcined at ゜ C is crushed and used.

In addition, a silicate or a mixture of a silicate and a Na ₂ O substance at a specific ratio is added to 100 parts by weight of the incinerated ash.
Addition of 30 to 30 parts by weight is because the supply of the glass melt is insufficient when the amount is 5 parts by weight or less, and the amount of the incinerated ash is reduced when the amount is more than 30 parts by weight, so that a large amount of incinerated ash cannot be treated.

Further, the weight ratio of (SiO ₂ + Al ₂ O ₃ ) / Na ₂ O
When the content is 9.0 to 1.0, if the content is 9.0 or more, the amount of the generated glass melt is small, the viscosity is increased, and the permeability between the incinerated ash particles is deteriorated. The reaction is difficult to proceed. Conversely, if it is 1.0 or less, 900-1
At a temperature of 100 ° C. or less, vitrification starts locally, deformation and foaming of the molded body occur, and the alkali elution degree of the sintered body increases. Optimum is (SiO ₂ + Al ₂ O ₃ ) / N by weight ratio
a ₂ O is 6.0 to 8.5.

As a mixture of the silicate and the Na ₂ O substance of the medium, feldspars (potassium feldspar, albite, plagioclase), nepheline,
Nepheline syenite, soda-lime glass mesolite, soda zeolites, etc. are used, and Na ₂ O, Si
Na ₂ O is added and replenished to a predetermined value according to the content of O ₂ and Al ₂ O ₃ .

The reason why BaO or B ₂ O ₃ is added as a medium dissolving aid in an amount of 5 parts by weight or less with respect to 100 parts by weight of the incinerated ash is that the viscosity is appropriately maintained in the sintering temperature range, This is to prevent foaming and deformation of the film. The reason why the addition amount is set to 5 parts by weight or less is that if it is more than 5 parts, the viscosity decreases and it becomes difficult to maintain the shape of the molded body. The solvent dissolving aid may not be added, but when it is added, a very small amount of 0.1 part by weight may be used.

The addition of a substance that volatilizes (OH), F, Cl and B ₂ O ₃ at a temperature of 600 ° C. or more as a reactant reduces the melting temperature of the medium and incinerated ash during sintering. This is to promote sintering by the evaporative condensation function. The substances include water of crystallization released at 600 ° C or more, fluorine,
A compound containing chlorine, boric acid, etc. is blended.

That is, among the reactants, the (OH) substance is water of crystallization (OH) in the incineration ash sintering temperature range of 600 ° C. or more.
Releases silicates, such as nepheline, nepheline syenite, Na-
Mica, scale mica, Na-zeolites, zunite, jadeite, Na-montmorillonite, sericite, etc., as the F substance, fluorite,
Soda or potassium silicofluoride, cryolite, fluoromica, etc .; Cl substance is salt, calcium chloride, magnesium chloride, etc .; B ₂ O ₃ substance is boric acid, borosilicate, borax, etc. It is. These become a sintering promoting material in combination with a solvent medium.

The addition range of 10 parts by weight or less to 100 parts by weight of the incinerated ash is within the usable range, and the addition of 10 parts by weight or more is not preferable because it causes melt foaming. This reactant does not have to be added in the case of incineration ash having a low melting temperature, but is effective in a small amount in the case of incineration ash having a high melting temperature. Good. The optimal range is 0.
1 to 5 parts by weight.

[0020]

According to the first aspect of the present invention, in the process of firing the molded body using the incineration ash and the medium-soluble base material, softening to a vitreous state starts at 600 to 700 ° C., and a glass melt is promptly supplied between the compounded particles. The fusion starts, and a large amount of incinerated ash starts to form a solid solution at around 1000 ° C., and the sintering is completed by about 1150 ° C., resulting in a dense and chemically stable sintered body. That is, medium soluble group material component and ash components, particularly, a reaction producing a glass and various crystals compatible of CaO-SiO _2, kinds of the crystals varies depending on the composition of the ash, but diopside ( CaO ・ MgO ・ 2SiO ₂ ), anorthite (CaO ・ Al ₂ O ₃・ 2Si)
O ₂ ) and single or plural eutectic materials such as β-wollastonite (β-CaO.SiO ₂ ). Further, in claim 2 in which a medium dissolution aid of BaO or B ₂ O ₃ substance is added, there is an effect that the viscosity is appropriately maintained and a good sintered body is obtained.

[0021] In the _{third aspect of the present invention} , a reactant which volatilizes (OH), F, Cl and B ₂ O ₃ at 600 ° C. or more is added. This causes evaporation, which lowers the melting point of the contacting particle surface and lowers the viscosity of the melt, remarkably promoting mass transfer between the particles, bonding the particles together, and precipitating the crystals to promote overall sintering. It is done.

[0022]

The embodiment will be described below. In Example 1, 100 parts by weight of the incineration ash A of the components in Table 2, 30 parts by weight of Na-feldspar as a solvent medium, 4 parts by weight of borax and 1 part by weight of Celsian as a solvent dissolving aid, and clay (SiO ₂₎ as a binder were used. 65%, blended with Al ₂ O ₃ 35%) 10 parts by weight were kneaded by adding water 10 to 20 parts by weight, then molding pressure 300
Press molding was performed at Kg / cm ² to obtain a green body of 65 × 65 × 10 mm. This was sufficiently dried, put into a heating furnace, heated at a rate of 150 ° C./hour, fired at 1100 ° C. for 1 hour, and then naturally cooled in the furnace.

The composition is shown in Table 1 together with Examples 2 to 6 with or without the addition of a solubilizing agent and / or a reactant, and the chemical components of incinerated ash A and incinerated ash B are shown in Table 2.
Shown in Table 3 shows the characteristics of the sintered bodies obtained by changing the heating conditions. According to these, a strong and chemically stable sintered body was obtained even when the medium dissolution aid or the reactant was not added.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

According to the first aspect of the present invention, the addition of the solvent-soluble base material starts softening to a vitreous state from 600 to 700 ° C., and the glass melt is rapidly supplied between the compounded particles to form incinerated ash and molten metal. Coating is started, and a large amount of incinerated ash starts to form a solid solution at around 1000 ° C, and sintering is completed by about 1150 ° C. A stable sintered body can be obtained. According to the second aspect, there is an effect that the viscosity is appropriately maintained in the sintering temperature range and foaming and deformation of the sintered body can be prevented.
It has the effect of evaporating to lower the melting point of the contact particle surface and lower the viscosity of the melt to promote sintering.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-76029 (JP, A) JP-A-58-36969 (JP, A) JP-A-58-156388 (JP, A) 189984 (JP, A) JP-A-2-12961 (JP, A) JP-A-4-278110 (JP, A) JP-A-5-58707 (JP, A) JP-A-5-330891 (JP, A) JP-A-7-155728 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B09B 3/00 C04B 35/00

Claims (3)

(57) [Claims] 1. A silicate or a silicate and a Na ₂ O substance having a weight ratio of (SiO ₂ + Al ₂ O ₃ ) / Na ₂ O of 9.0 to 1.0 with respect to 100 parts by weight of the incinerated ash. 5 as a solvent base
A method for producing an incinerated ash sintered body, which comprises adding up to 30 parts by weight, forming and sintering at 900 to 1150 ° C. 2. BaO or B ₂ O per 100 parts by weight of incinerated ash
_{2. The} method for producing an incinerated ash sintered body according to claim 1, wherein the composition is a mixture containing 3 parts by weight of 5 mass parts or less as a medium dissolution aid. 3. 600 ° C. for 100 parts by weight of incinerated ash
_{2. A} composition containing 10 parts by weight or less of a substance which volatilizes (OH), F, Cl and B ₂ O ₃ as a reaction material.
Or the manufacturing method of the incinerated ash sintered compact of Claim 2.