JPH07185504A - Production of incineration ash sintered body - Google Patents

Abstract

PURPOSE:To lower the calcination temp. of incineration ash contg. large amount of high melting point material to make the control of a calcination process easy by adding a specific glass composition as a fluxing material and alkaline metal oxide, alkaline earth metal oxide, etc., as a fluxing assistant, then forming and sintering them. CONSTITUTION:In case of obtaining a sintered body to be used for various kinds of materials, such as road paving materials (such as tiles and paving plates), and building interior and exterior materials requiring high strength, by using incineration ash generated in the treatment of sewage sludge, municipal refuse, etc., 5-35 pts.wt. of a glass composition having chemical composition of 50-75 SiO2, 1-3 Al2O3, 5-10 CaO, 0-5 MgO, 5-15 Na2O, and 0-5 K2O by wt.% are added as a fluxing agent to 100 pts.wt. of incineration ash. And <=5 pts.wt. of one of alkaline metal oxide, alkaline earth metal oxide, fluoride and their compounds or their composite mixture are added as a fluxing assistant. After forming, the formed body is sintered at 900-1150 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method for obtaining a chemically stable sintered body by utilizing incinerated ash obtained by treating sewage sludge, municipal waste, etc. It is intended to obtain a sintered body that can be used as various materials such as road paving materials and building interior and exterior materials that require high strength.

[0002]

2. Description of the Related Art Sewage sludge and municipal solid waste, which have been inevitably generated in large quantities, are incinerated at a cleaning plant or the like to produce incinerated ash as a residue. Instead of dumping into the ocean, it is being effectively recycled.

Generally, the composition of incinerated ash is such that the main components are wt%, SiO ₂ is ₂₀ to 45, Al ₂ O ₃ is 5 to 17, CaO is 5 to 5.
40, 5 to 15 for Fe ₂ O ₃ , 0 to 20 for P ₂ O ₅ , and 0 to 7 for MgO
It fluctuates in the range of. The melting temperature of the incineration ash is 1
It is a high temperature substance of 300 to 1500 ° C, and it also contains P ₂ O ₅ , so it is highly erodible, it tends to be alkaline in nature and is chemically unstable, and it is a waste of sewage sludge and municipal waste. The composition of incineration ash is not constant due to the difference in generation source and treatment system.

At present, as a method for recycling incinerated ash, the incinerated ash is again heated and melted at 1300 to 1500 ° C. to produce glass, ceramics and crushed stone by casting, and the incinerated ash alone or a large amount of clay or the like in the incinerated ash. It is used to make ceramic products such as bricks and tiles by adding a plastic material and molding and firing with a press.

However, the method for remelting the incineration ash requires a special melting furnace because it has erosiveness due to the alkali component of the melt and P ₂ O ₅ , and the composition of the incineration ash fluctuates. Was not constant, and the product characteristics became inhomogeneous, and chemical stability was particularly lacking.

[0006] In addition, in the method of forming and burning bricks or tiles by adding incineration ash alone or a plastic material, the incineration ash component Ca
High-melting substances such as O, SiO ₂ and Al ₂ O ₃ raise the firing temperature, and when clay-based plasticizers are added, high-temperature and long-term firing is required to obtain a homogeneous solid solution sintered body. There is a necessary defect, and in both cases there is a problem that the management of the firing process becomes complicated due to the fluctuation of the incineration ash composition, the product characteristics are not stable, and there is a possibility of secondary pollution due to elution because there is no improvement in the alkaline constitution. there were. When plasticizer is added, the moldability is secured, but there is also a drawback that a large amount of waste incineration ash cannot be processed.

[0007]

Therefore, the present invention simplifies the control of the firing process by lowering the firing temperature of the incineration ash containing a large amount of high melting point substances, and at the same time, maintains the product characteristics, particularly chemical stability. However, it is possible to prevent secondary pollution due to elution, and to provide a method for producing an incinerated ash sintered body which is capable of treating a large amount of waste incinerated ash.

[0008]

Therefore, according to the first invention of the present invention, the chemical composition is 100 wt.
SiO ₂ is 50-75, Al ₂ O ₃ is 1-3, CaO is 5-10, Mg
A glass composition having 0 to 5 for O, 5 to 15 for Na ₂ O, and 0 to 5 for K ₂ O is used as a solvent, and 5 to 35 parts by weight of alkali metal oxide, alkaline earth metal oxide, fluorine And a mixture of a single species or a complex species of these compounds is added as a solvent aid in an amount of 5 parts by weight or less, and the mixture is molded and sintered at 900 to 1150 ° C.

The second invention of the present invention is that the incineration ash has a chemical composition of 50% by weight, SiO ₂ is 50 to 68, Al ₂ O ₃ is 1 to 6, and CaO is 2.
-10, MgO 2-10, Na ₂ O 3-18, F 0-3,
K ₂ O is 0 to 15, B ₂ O ₃ is 0 to 5, BaO is 0 to 5, SrO is 0.
˜5, TiO ₂ is 0 to 3, ZrO ₂ is 0 to 3 and a ceramic raw material powder composition or glass powder is added as a sintering accelerator,
It is a method for producing an incinerated ash sintered body, which is produced by molding a mixture adjusted to have a CaO / (SiO ₂ + Al ₂ O ₃ ) ratio of 1.0 or less and sintering the mixture at 900 to 1150 ° C.

In the first invention, with respect to 100 parts by weight of incinerated ash,
The specific high silicate glass composition, that is, the chemical composition in% by weight
SiO ₂ is 50-75, Al ₂ O ₃ is 1-3, CaO is 5-10, Mg
Addition of 5 to 35 parts by weight of a glass composition as a medium material having 0 to 5 for O, 5 to 15 for Na ₂ O, and 0 to 5 for K ₂ O is to fuse with incinerated ash at low temperature. To solid solution.
That is, a low-viscosity glass melt is generated between the particles of the incinerated ash at a low temperature, and they are solid-solved with each other to integrate the particles.
The glass composition in this range has a softening temperature of 600 to 700 ° C and a melting temperature of around 1000 ° C. Therefore,
The glass composition begins to soften at 600 to 700 ° C and begins to fuse with the incinerated ash, and begins to form a solid solution in the incinerated ash in the melting temperature range around 1000 ° C, but since the amount of incinerated ash is large, it is a melt. The viscosity becomes high, and further high temperature and time are required for the progress of sintering.

Therefore, alkali metal oxides, alkaline earth metal oxides (Na ₂ O, K ₂ O, L ₂ O, BaO, SrO) and fluorides (K
5 parts by weight or less of F, NaF, CaF ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ ) and a mixture of a single species or a complex species of these compounds is added as a solvent aid. These medium-dissolving aids have the effect of not only the medium-dissolving action but also the viscosity of the whole mixture of the sintered body to significantly reduce the viscosity and increase the supply and permeation of the melt between particles. It volatilizes at the time of binding and acts to lower the melting point of each component of the formulation. Due to the joint action of the medium-melting material and the medium-melting aid of the glass composition,
By holding for 2 hours, sintering is completed and a dense sintered body can be obtained.

The composition obtained by adding the glass composition and the solvent aid to the incineration ash is a wet or dry molding, and if necessary, a binder such as an organic binder or a clay plastic material. However, as a conventional molding binder, a 1% or less solution of organic CMC, acrylic polymer, PVA, starch or the like, kaolin as an inorganic plasticizer,
Bentonite, water glass, etc. are blended in an amount of 0 to 20 parts by weight with respect to 100 parts by weight of incinerated ash.

The glass composition is added in an amount of 5 to 35 parts by weight with respect to 100 parts by weight of the incinerated ash. This is because if the amount is 35 parts by weight or more, the amount of incinerated ash used will be so small that it cannot be processed in large quantities. Its chemical composition is wt%, SiO ₂ is 50-75, Al
₂ O ₃ is 1-3, CaO is 5-10, MgO is 0-5, Na ₂ O is 5
15, the K ₂ O is 0 to 5 is 600-700 ° C
This is for softening at about 1000 ° C and melting.

Further, the amount of alkali metal oxide, alkaline earth metal oxide, fluoride and a mixture of a single species or a complex species of these compounds is 5 parts by weight or less is the viscosity adjustment of the incineration ash formulation and the incineration ash formulation. This is because the melting point of each component of the product is lowered. Therefore, it is not necessary to add these medium-solubilizing agents, but it is preferably 0.1 to 5 parts by weight.

Further, in the second invention, the chemical composition is 50% by weight, SiO ₂ is 50 to 68, and Al ₂ O ₃ is 1 relative to 100 parts by weight of incinerated ash.
~ 6, CaO 2-10, MgO 2-10, Na ₂ O 3-1
8, F is 0 to 3, K ₂ O is 0 to 15, B ₂ O ₃ is 0 to 5, BaO is
0.5-5, SrO 0.5-5, TiO ₂ 0-3, ZrO ₂ 0-3
The reason for adding the ceramic raw material powder composition or glass powder having the above composition is to promote sintering. The material form is
It is a powdery mixture in which ceramic materials suitable for the composition are mixed, or a glass powder suitable for the composition. It is desirable that the ceramic raw material powder is preliminarily calcined at 700 ° C. or higher to volatilize and remove the intervening water and crystal water, and thus the sintering activity is large.

A ceramic raw material powder composition or glass powder was added as a sintering accelerator, and its CaO / (SiO ₂ + Al ₂ O ₃ ) ratio was 1.
Adjust the alkaline component (Ca
O) and acidic components (SiO ₂ + Al ₂ O ₃ ) are added to compensate for safe solid solution to neutralize the physical properties of the molded product, improve chemical stability, and improve low-temperature sintering. As in the first invention, it is possible to improve the low temperature sintering in the range of 600 to 70.
Softening starts at 0 ° C and fusion with incinerated ash begins, and the melting point of each component of the compound is lowered by adding a sintering accelerator to 1000
This is because the incineration ash begins to form a solid solution at around ° C and the sintering is completed at about 1100 ° C. Further, the amount of the ceramic raw material powder composition or glass powder as a sintering accelerator is appropriately 5 to 35 parts by weight in the incineration ash compounded molded product, and if it is more than that, the amount of incineration ash used becomes small. It is unsuitable because a large amount of treatment cannot be achieved. Below that, neutralization is difficult and unsuitable.

It should be noted that ceramic raw material powder composition or glass powder, whose chemical composition is% by weight, SiO ₂ is 50 to 68, and Al ₂ O ₃ is 1 to 1.
6, CaO 2-10, MgO 2-10, Na ₂ O 3-18,
F is 0 to 3, K ₂ O is 0 to 15, B ₂ O ₃ is 0 to 5, and BaO is 0.
5, SrO is 0 to 5, TiO ₂ is 0 to 3, and ZrO ₂ is 0 to 3 has a large amount of neutralizing SiO ₂ and is softened at a low temperature.
This is because the melting becomes good.

A composition obtained by adding a ceramic raw material powder composition or glass powder to this incinerated ash is one which is molded by a wet or dry method,
If necessary, it may be molded with a binder such as an organic binder or a clay plastic material. As a conventional molding binder, a 1% or less solution of organic CMC, acrylic polymer, PVA, starch, etc., inorganic plastic Kaolin as a material,
Bentonite, water glass, etc. are blended in an amount of 0 to 20 parts by weight with respect to 100 parts by weight of incinerated ash.

[0019]

In the first aspect of the invention, the glass composition of the added solvent material begins to soften at 600 to 700 ° C. and starts to fuse with the incinerated ash, and is mixed by adding a solvent aid such as an alkali metal oxide. The melting point of each component of the product is lowered and the incinerated ash begins to form a solid solution at around 1000 ° C, and the sintering is completed by about 1150 ° C, and a dense sintered body can be obtained.

In the second invention, the ceramic raw material powder composition or the glass powder is added as the sintering accelerator after adjusting the CaO / (SiO ₂ + Al ₂ O ₃ ) ratio to be 1.0 or less. The composition begins to soften from 600 to 700 ° C and begins to fuse with the incinerated ash, and begins to form a solid solution with the incinerated ash at around 1000 ° C, and the sintering is completed by about 1150 ° C to neutralize. Therefore, it is possible to obtain a dense sintered molded product with improved chemical stability.

The composition of the sintering promoting material is as follows: anorthite (CaO.Al ₂ O ₃ .2SiO ₂ ), β-wollastonite (CaO.S
iO ₂ ) is included in the composition for precipitating crystals, and crystal nucleus components TiO ₂ and ZrO ₂ that promote the precipitation of these crystals are included. Therefore, since the composition of the incineration ash is the SiO ₂ -CaO-Al ₂ O ₃ system, the glass phase formed by the composite sintering of this sintering accelerator with SiO ₂ -CaO-MgO-F is diopside. (CaO / MgO / 2Si
O ₂ ), wollastonite, calcium silicate fluoride (Ca _{2 to 4} Si _{1 to 2} O _{2 to 7} F ₂ ), etc.
It has the effect of precipitating any of these microcrystals or acicular crystals in a symbiotic state in the sintered body to reinforce the strength. Therefore, it can be used not only as a road paving material, but also as a building interior / exterior material or a structural material that requires high strength.

[0022]

Embodiments 1 to 4 Hereinafter, the embodiments will be described. In Example 1 of the first invention, 100 parts by weight of incinerated ash A was added,
35 parts by weight of high silicate glass as a solvent, 3 parts by weight of feldspar as a solvent, 1.5 parts by weight of barium fluoride, and 10 parts by weight of clay as a binder are mixed, and 10 to 20 parts by weight of water is added and kneaded. Then, it was press-molded at a molding pressure of 300 kg / cm ² to obtain a green body of 65 × 65 × 10 mm. Dry it thoroughly, put it in a heating furnace and raise the temperature at a rate of 150 ° C / hr.
After firing at 1100 ° C for 1 hour, the furnace was naturally cooled.

The composition is shown in Table 1 together with Examples 2 to 4 of the first invention, and Table 2 shows the chemical components of the incinerated ash A, the incinerated ash B and the high silicate glass. Table 3 shows the characteristics of the sintered bodies obtained by changing the heating conditions.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

The sintered bodies of Examples 1 to 4 of this example all had high strength and good chemical stability.

[0028]

[Examples 5 to 8] This is an example of the second invention, and the incineration ash A and B shown in Table 2 were used so that the component ratios shown in Table 4 were obtained.
The sintering accelerator A is blended. Sintering accelerator A is feldspar (K ₂ O, Al
₂ O ₃ , SiO ₂ ) Sergian (BaO, Al ₂ O ₃ , SiO ₂ ), magnesite (MgO), fluorite (CaO, F), borax (Na ₂ O, B ₂ O ₃ ), sodium fluoride ( Na ₂ O, F), titanium oxide (TiO ₂ ), light ash (Na ₂ O), barium carbonate (BaO), soda-lime glass (SiO ₂ , CaO, Na ₂ O, A)
L ₂ O ₃ ) is used as a raw material, and this is calcined at 800 ° C. for 3 hours and then crushed to give a CaO / (SiO ₂ + Al ₂ O ₃ ) ratio of 0.1.
It was prepared to be ~ 0.7. The formulations are shown in Table 5 as Examples 5-8.

To this, 10 to 20 parts by weight of water was added and kneaded, and then press-molded at a molding pressure of 300 Kg / cm ² to obtain 65 × 6.
A 5 × 10 mm green body was obtained. This was sufficiently dried, placed in a heating furnace, heated at a rate of 150 ° C./hour, treated under the heating conditions shown in Table 6 together with Examples 5 to 8, and then naturally cooled in the furnace. As shown in Table 6, the obtained sintered body was a good sintered body having a bending strength of 400 kg / cm ² or more, and X
As a result of analysis by a linear diffraction method, precipitation of a composite crystal phase of diopside and calcium silicate fluoride was observed.

[0030]

[Table 4]

[0031]

[Table 5]

[0032]

[Table 6]

[0033]

[Examples 9 to 12] Another example of the second invention, in which the incinerated ashes A and B shown in Table 2 were used so that the component ratios shown in Table 7 were obtained.
A sintering accelerator B is added. The sintering accelerator B is feldspar (K ₂ O, Al
₂ O ₃ ,, SiO ₂ ) Silica (SiO ₂ ), Magnesite (MgO), Fluorite
(CaO, F), borax (Na ₂ O, B ₂ O ₃ ), sodium fluoride (Na ₂ O,
F), titanium oxide (TiO ₂ ), light ash (Na ₂ O), barium carbonate (Ba
O) was used as a raw material, and this was melted at 1350 ° C. for 2 hours, and the molten glass was granulated to prepare. The formulations are shown in Table 8 as Examples 9-12.

To this, 10 to 20 parts by weight of water was added and kneaded, and then press-molded at a molding pressure of 300 kg / cm ² to obtain 65 × 6.
A 5 × 10 mm green body was obtained. This was sufficiently dried, placed in a heating furnace, heated at a rate of 150 ° C./hour, treated with the heating conditions shown in Table 9 together with Examples 9 to 12, and then naturally cooled in the furnace. As shown in Table 9, the obtained sintered body was a good sintered body having a bending strength of 400 kg / cm ² or more,
As a result of X-ray diffraction analysis, precipitation of a composite crystal phase of diopside and calcium silicate fluoride was observed.

[0035]

[Table 7]

[0036]

[Table 8]

[0037]

[Table 9]

[0038]

According to claim 1 of the present invention, the glass composition of the added solvent material begins to soften at 600 to 700 ° C. and starts to fuse with the incinerated ash to dissolve an alkali metal oxide or other solvent. Addition of auxiliary materials lowers the melting point of each component of the compound to 100
The incineration ash begins to form a solid solution at around 0 ° C, and the sintering is completed by about 1150 ° C, so that a dense sintered body can be obtained at low cost. Further, in claim 2, the ceramic raw material powder composition or the glass powder is used as the sintering promoter in the CaO / (SiO ₂
Since the + Al ₂ O ₃ ) ratio was adjusted and added to be 1.0 or less, the ceramic raw material powder composition or the glass powder was 600 to 70.
Softening begins at 0 ° C and begins to fuse with incinerated ash,
The incineration ash begins to form a solid solution at around 00 ° C, the sintering is completed up to about 1150 ° C, neutralization can be achieved, and a dense sintered molded product with improved chemical stability can be obtained. The strength of the product is increased and its usage is expanded.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication C04B 35/64 B09B 3/00 304 G C04B 35/64 Z (72) Inventor Tadashi Ozeki Seto Aichi Prefecture 136 Shiogusa-cho, Ichi, Japan Ootsuke Serum Co., Ltd. (72) Inventor Michio Fujita 136-Shiogusa-cho, Seto City, Aichi Prefecture

Claims (2)

[Claims] 1. The chemical composition is 50% by weight, SiO ₂ is 50 to 75, Al ₂ O ₃ is 1 to 3 and CaO is 5 to 100 parts by weight of incinerated ash.
10, 5 to 35 parts by weight of a glass composition having MgO of 0 to 5, Na ₂ O of 5 to 15 and K ₂ O of 0 to 5 as a solvent, an alkali metal oxide or an alkaline earth metal oxide. Of the incineration ash sintered body, characterized in that 5 parts by weight or less of a fluoride or a mixture of these compounds as a solvent aid is added and molded and sintered at 900 to 1150 ° C. Production method. 2. The incineration ash has a chemical composition of wt% and SiO ₂ of 5%.
0-68, Al ₂ O ₃ 1-6, CaO 2-10, MgO 2-2
10, Na ₂ O is 3 to 18, F is 0 to 3, K ₂ O is 0 to 15, B ₂
O ₃ is 0 to 5, BaO is 0 to 5, SrO is 0 to 5, TiO ₂ is 0 to
3, the ceramic raw material powder composition of the composition of ZrO ₂ is 0 to 3 or glass powder is added as a sintering accelerator, CaO / (SiO ₂
A method for producing an incinerated ash sintered body, which comprises molding a mixture adjusted to have a + Al ₂ O ₃ ) ratio of 1.0 or less and sintering the mixture at 900 to 1150 ° C.