JPH11268942A - Inorganic hardened material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a material for civil enginnering/construction, by baking a material to be incinerated such as municipal waste, sewage sludge, etc., to give incinerated ash, rebaking the incinerated ash to give a part of raw material so that an organic component, chlorine, heavy metal, etc., contained in the material to be incinerated are removed. SOLUTION: Incinerated ash obtained by incinerating municipal waste, etc., is rebaked at a temp. of >=1,000 deg.C, generally 1,000-1,400 deg.C to vaporize and to remove a heavy metal, a hardening inhibiting substance, dioxin, etc. The vaporized heavy metal is recovered in a post-processing. The baked ash obtained by baking the incinerated ash may be treated as it is with a chelating agent or an alkali and used. The baked ash is mixed with a cement hydrate, gypsum or calcium silicate alone or its combined material as a matrix phase to give a hydraulic composition. The hydraulic composition comprises gypsum and a baked material containing 10-40 wt.% C11 A7 CaCl2 and C2 S and C3 S. Preferably a material using a waste is used as a cement to reduce the cost and to effectively use a resource.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic cured product using incinerated ash as a raw material, and more particularly, to a heat treatment for removing organic components, chlorine, heavy metals, dioxins, etc. contained in the incinerated ash. The present invention relates to an inorganic hardened material composed of the incinerated ash and an inorganic matrix, whereby the incinerated ash can be used safely and in large quantities.

[0002]

2. Description of the Related Art The incineration ash generated by the incineration of waste such as municipal waste and sewage sludge is most commonly disposed of by landfill. This is a major problem. In particular, securing a new disposal site is difficult due to local and environmental issues, making it even more difficult to solve the problem. In addition, these incinerated ash
It has been revealed that harmful substances such as dioxins, as well as heavy metals such as cadmium and cyanide, are contained, and the resulting soil pollution and effects on human bodies have become serious problems.

[0003] For this reason, stabilization of solidification of incinerated ash with cement has been proposed and put into practical use for the purpose of suppressing and preventing elution of heavy metals and dioxins. Although this measure avoided serious problems such as soil contamination, the various organic components still contained by the incineration ash could inhibit the hydration-hardening reaction of the cement or, as a result, weaken the solidified material Some of them cannot be subjected to the solidification and stabilization treatment because of the problem of causing the solidification and stabilization.

On the other hand, in the field of civil engineering and construction, incinerated ash is used as a filler for cement, as a filler for backfilling or backfilling materials, or as a substitute for siliceous raw materials because it contains SiO _2. Has been used as. But,
As described above, some incinerated ash contains an organic substance, which may inhibit the hardening reaction of cement, resulting in lower product performance. At present, it has to be narrowed.
Further, since chlorine is contained in addition to the organic matter, there is also a problem that the reinforcing steel of the concrete structure is corroded, and its use range is limited.

[0005] As described above, there is a need for technical improvement for detoxifying and stabilizing incinerated ash, technology for effectively using incinerated ash, and effective measures for dealing with a large amount of incinerated ash.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is intended to remove organic components, chlorine, heavy metals, dioxins and the like contained in incineration ash by performing a heat treatment. By doing so, it is possible to use incinerated ash safely and in large quantities, and to provide an inorganic cured product excellent in various physical properties.

[0007]

Means for Solving the Problems In view of the actual situation, the present inventors have conducted various studies on the technology for mass use of incinerated ash.
It was concluded that complexing with various inorganic matrices to form a cured product could provide a wide range of applications including civil engineering and construction materials. From this, as a result of various studies on the incineration ash that does not adversely affect the intended complex treatment,
The inventor has found that the object has been achieved by using the incinerated ash obtained by firing the incinerated material, which has been fired again at least once, and completed the present invention.

[0008] That is, the present invention provides an inorganic hardened material using the incinerated ash obtained by firing an incinerated material at least once again, and using this as a part of the raw material.
Further, the present invention provides the above-described inorganic cured product, wherein the incinerated material is at least one selected from the group consisting of municipal waste and sewage sludge. Further, the present invention provides the above-mentioned cured inorganic material, wherein at least one selected from the group consisting of cement hydrate, gypsum and calcium silicate is used as a matrix phase. Furthermore, the present invention provides the above-mentioned inorganic cured product, in which the matrix phase of the inorganic cured product is formed by curing a hydraulic composition having the following requirements: municipal waste incineration ash and sewage sludge incineration. a hydraulic composition comprising one or more of the burned material selected from the group consisting of ash, include C ₁₁ a ₇ CaCl ₂ 10~40 wt%, and from the group consisting of C ₂ S and C ₃ S It includes a calcined product containing one or more selected materials and gypsum.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The inorganic hardened material of the present invention is obtained by firing an incinerated ash obtained by firing an object to be incinerated at least once, and using this as a part of the raw material. In order to avoid the incineration, the first one obtained by firing the incineration material is simply called "incineration ash", and the ash obtained after the second firing is called "calcination ash". The second baking is for the purpose of removing organic substances that cause hardening inhibition of the matrix phase, chlorine that generates rust on reinforcing bars, etc., volatilization of heavy metals that may be eluted, and decomposition of dioxins. It is. Therefore, the second firing conditions must be suitable for this purpose. That is, when only removing organic components is considered, 500 to 600 ° C.
Although heat treatment of a certain degree is sufficient, chlorine-containing substances and heavy metals do not volatilize in this temperature range. Therefore, it is desirable to sufficiently perform a baking treatment at 1000 ° C. or higher in a state where dioxins and the like are not generated in order to remove these repellent components.
The second firing temperature is usually 1000 to 1400 ° C. In addition, the baking treatment can be performed two or more times as needed for the purpose of further removing the repellent components. Further, the volatilized heavy metal is recovered in a subsequent step.

[0010] The calcined ash in the present invention is obtained by calcining incinerated ash under the above calcining conditions, and the incinerated ash to be calcined is not particularly limited, and municipal waste incinerated ash, sewage sludge incinerated ash, paper Sludge incineration ash and the like. The fired ash used in the present invention may be not only fired ash obtained by firing only incinerated ash, but also fired ash obtained by performing chemical treatment or the like after firing of incinerated ash. Here, the calcined ash that has been subjected to the chemical treatment refers to calcined ash that has been subjected to a stabilizing treatment with a chemical such as a chelating agent, calcined ash that has been subjected to an alkali treatment and has a metal oxide contained in the calcined ash as a hydroxide, A calcined ash or the like, in which a calcium raw material or a siliceous raw material is added to the ash and subjected to a hydrothermal reaction to generate a calcium silicate hydrate composed of CaO and SiO _2, is mentioned. Among them, municipal waste incineration ash, sewage sludge incineration ash, and a combination thereof are preferable.

The inorganic cured product of the present invention contains the above-mentioned calcined ash and a matrix phase. The matrix phase is preferably composed of at least one of cement hydrate, gypsum and calcium silicate. . Since these matrix phases may cause curing inhibition or reduce the physical properties of the cured product due to organic substances, chlorine content, etc., good complexation with the calcined ash from which these components have been removed is achieved. This is preferable because it can be realized.

That is, when cement hydrate is selected as the matrix phase, the calcined ash is not only preferable because it does not contain an organic component that inhibits its hardening, and also has chlorine removed, so that the reinforcing steel rusts. Without
It is preferable because it can be applied to a cement structure reinforced with a reinforcing bar or a lath. Further, depending on the curing conditions at the time of curing or after curing, the calcined ash serves as a silica source to generate a reaction product such as calcium silicate between the cement and the calcined ash. Physical properties can also be improved. When cement hydrate is selected as the matrix phase, the cement used is not particularly limited,
Cement such as ordinary cement, early-strength cement, alumina cement, and fly ash cement can be used.

Further, when gypsum is selected as the matrix phase, similarly to the case of the cement, it is possible to avoid the inhibition of the hardening due to the organic components, and to obtain a hardened product having excellent strength properties and the like.

Further, when calcium silicate is selected as the matrix phase, not only is it preferable that the formation of calcium silicate by the organic component is not inhibited, but also the calcined ash should supply calcium and silica as reaction components. It is preferable because it can also be performed.

Apart from this, a hydraulic composition made from calcined ash can be used as the matrix phase. Specifically, it is a hydraulic composition containing at least one burned material selected from the group consisting of municipal garbage incineration ash and sewage sludge incineration ash, which contains 10 to 40% by weight of C ₁₁ A ₇ CaCl _2. And a calcined product containing at least one selected from the group consisting of C ₂ S and C ₃ S, and gypsum. This hydraulic composition may be prepared for this purpose, or may be prepared, for example, from the environmentally-friendly hydraulic composition disclosed in JP-A-7-165446, or to the hydraulic composition described in JP-A-7-165449. Hard mixed cement or cement (eco-cement) using living / industrial waste disclosed in Japanese Patent Application No. 8-64486 can also be used. In particular, eco-cement is, specifically, a burned material such as municipal ash, sewage sludge incineration ash, and the like, which is preferable from the viewpoint of reducing the cost of the cement itself and effective use of resources.

The form of gypsum used in the hydraulic composition is as follows:
There is no particular limitation, and gypsum dihydrate, α-type / β-type hemihydrate gypsum, type-III anhydrous gypsum, type-II anhydrous gypsum and the like can be used alone or in combination. The amount of gypsum is not particularly limited, but the molar ratio is preferably 0.4 to 3.0, preferably 0.5 to 2.0 with respect to Al ₂ O ₃ in the hydraulic composition. . Depending on the cement raw material, gypsum may coexist in the hydraulic composition, but in this case, the molar ratio of SO ₃ / Al ₂ O ₃ is selected.

The above-mentioned hydraulic composition is used as a part or all of the matrix phase, but when it is used as a part, it is usually made of portland cement, high-strength cement, highly basic calcium chlorosilicate (eg, alinite, berynite), calcium Fluoroaluminate (C ₁₁ A ₇ CaF ₂ ), Irwin (C ₃ A ₃ CaSO ₄ ) or a mixture with other cements can be used.

Since this hydraulic composition uses waste as a raw material, it does not only meet the object of the present invention in that it effectively utilizes a large amount of waste, but also has a very fast curing itself.
There is also an advantage that it can be manufactured at low cost because high productivity can be secured.

In the inorganic cured product of the present invention, an aggregate, a reinforcing material, a lightening material, various admixtures, and additives are appropriately added and blended according to the performance of the target product and the production process. be able to.

The cured inorganic material of the present invention undergoes some curing as needed during the production process. Curing usually includes normal temperature / normal pressure curing, steam curing, high temperature / high pressure curing, etc., and these are appropriately selected according to the type of matrix phase and the performance of the target product. Normally, normal temperature / normal pressure curing and steam curing are used for manufacturing concrete products and the like, and high temperature / high pressure curing is used for manufacturing lightweight cellular concrete (ALC) using calcium silicate as a matrix, heat insulating material and the like.

[0021]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. 1. Incinerated ash and calcined ash The incinerated ash used in the present invention is municipal waste incinerated ash, and its chemical components are shown in Table 1. The calcined ash is obtained by calcining the municipal waste incinerated ash once more at 1200 ° C. for 6 hours. The chemical components are also shown in Table 1.

[0022]

[Table 1] Ignition loss SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO Na ₂ OK ₂ O Cl ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Incinerated ash 8.7 27.8 16.9 5.1 25.6 2.5 4.1 3.9 9.3 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Burnt ash 0.1 32.1 23.4 6.0 31.2 3.2 1.1 0.7 0.3 ━単 位 Unit: weight%

Since the calcined ash has been calcined at 1200 ° C. for 6 hours, the ignition loss is 0.1% by weight and chlorine is 0.3% by weight. This means that organic components and chlorine have been significantly removed.

2. Materials used The materials used for preparing the inorganic cured product are shown below. -Cement: ordinary Portland cement (made by Chichibu Onoda Co., Ltd.)-Hydraulic composition: Eco-cement (made by Chichibu Onoda Co., Ltd.)-Silica sand: Toyoura silica sand (made by Toyoura Silica Mining Co., Ltd.)-Hemihydrate gypsum: gypstone (Made by San-Esu Gypsum Co., Ltd.) ・ Silica: Toane Silica Stone (manufactured by Seto Ceramics Co., Ltd.) ・ Slaked Lime: (manufactured by Kotegawa Sangyo Co., Ltd.) ・ Gypsum dihydrate: Gypsum natural dihydrate (from southern Thailand) ・ Diatomite: Radiolite SPF (manufactured by Hakusan Industry Co., Ltd.)-Water reducing agent: Naphthalene sulfone-based water reducing agent-Slag: (manufactured by Sumikin Kashima Mineralization Co., Ltd.)-Glass fiber: alkali-resistant glass fiber 13 mm chopped strand (Nippon Electric Glass ( Co., Ltd.)

3. Evaluation method The evaluation of the inorganic cured product was performed by the following method. (1) Bending strength The bending strength was measured using an Instron universal testing machine. Width 4 cm, length 16 cm, thickness 4 cm (Example 1,
Inorganic cured products of size 3 and 4) span 14 cm; width of 4 cm, length 20 cm, thickness of 1 cm (Examples 2 and 6). Inorganic cured products of size 18 cm; span 4 cm, length 20 cm. The cured inorganic material having a thickness of 2 cm (Example 5) was measured at a span of 18 cm. (2) Compressive strength The half-piece after measuring the flexural strength was measured for compressive strength using an Instron universal testing machine according to JIS R5201. (3) Identification of composition The composition of the matrix of the inorganic cured product was identified using an X-ray diffractometer RINT1000 (manufactured by Rigaku Corporation).

(Example 1 and Comparative Example 1) Cement 10
0 parts by weight, incinerated ash or calcined ash 30 parts by weight, silica sand 20
0 parts by weight and 70 parts by weight of water are mixed and poured into a mold.
After curing and curing at 0 ° C. and a relative humidity of 95% for 24 hours, the resulting product was demolded to prepare an inorganic cured product having a cement hydrate as a matrix phase. In Example 1, calcined ash was used, and in Comparative Example 1, incinerated ash was used to produce an inorganic cured product. The resulting cured inorganic material was cured in water at 20 ° C. for one week, and the flexural strength and compressive strength were measured. Table 2 shows the measurement results. SiO ₂ and Al ₂ O ₃ contained in the incineration ash form a cement hydrate by a hydration reaction with the cement and harden. That is, SiO
₂ , lime, calcium silicate hydrate by reaction with water,
Al ₂ O ₃ generates ettringite by reaction with lime gypsum and becomes a matrix phase cement hydrate and hardens.

[0027]

[Table 2] Example 1 Comparative Example 1 ━━━━━━━━━━━━━━━━━━━━ Specific gravity (g / cm ³ ) 1.7 1.7 Flexural strength (kgf / cm ² ) 39 12 Compressive strength (kgf / cm ²⁾ ) 211 67 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

In Example 1, an inorganic cured product having higher flexural strength and compressive strength than Comparative Example 1 was obtained. For this reason, by using calcined ash, it is possible to provide an inorganic cured product having high strength.

(Example 2 and Comparative Example 2) Hemihydrate gypsum 10
0 parts by weight, 20 parts by weight of incinerated ash or calcined ash, and 50 parts by weight of water are mixed, poured into a mold, cured, demolded, and heated to 45 ° C.
For 24 hours to prepare an inorganic cured product using gypsum as a matrix phase. In Example 2, calcined ash was used, and in Comparative Example 2, incinerated ash was used to produce an inorganic cured product. The bending strength of the obtained inorganic cured product was measured. Table 3 shows the measurement results.

[0030]

[Table 3] Example 2 Comparative Example 2 {Specific gravity (g / cm ³ ) 1.1 1.1 Flexural strength (kgf / cm ² ) 69 23} ━━━━━━━━━━━━━━━━━━━━━━━

In Example 2, an inorganic cured product having higher flexural strength than Comparative Example 2 was obtained. For this reason, by using calcined ash, it is possible to provide an inorganic cured product having high strength.

(Example 3 and Comparative Example 3) Cement 10
0 parts by weight, 450 parts by weight of silica, 70 parts by weight of slaked lime, 25 parts by weight of gypsum dihydrate, 15 parts by weight of incinerated ash or calcined ash, water 3
0 parts by weight were mixed, poured into a mold, cured, and then released. Temperature of 180 ° C, pressure of 10kg / c
Cured under an atmosphere of m ² for 12 hours to prepare an inorganic cured product using tobermorite, which is calcium silicate, as a matrix phase. In Example 3, calcined ash was used, and in Comparative Example 3, incinerated ash was used to produce an inorganic cured product. The obtained cured inorganic material was dried at 45 ° C. for 24 hours, and the bending strength was measured. Table 4 shows the measurement results.

[0033]

[Table 4] Example 3 Comparative Example 3 {Specific gravity (g / cm ³ ) 1.5 1.5 Flexural strength (kgf / cm ² ) 128 78} ━━━━━━━━━━━━━━━━━━━━━━━

In Example 3, an inorganic cured product having higher flexural strength than that of Comparative Example 3 was obtained. For this reason, by using calcined ash, it is possible to provide an inorganic cured product having high strength.

Example 4 and Comparative Example 4 100 parts by weight of the hydraulic composition, 100 parts by weight of incinerated ash or calcined ash, 1 part by weight of pulp fiber, 35 parts by weight of water, and 2 parts by weight of a water reducing agent were mixed together. Pour into a frame, cure at 90 ° C for 30 minutes, and cure,
Demolding was performed to prepare an inorganic cured product using cement hydrate as a matrix phase. Example 4 used calcined ash and Comparative Example 4 used incinerated ash to produce an inorganic cured product. The hydraulic compositions used in the present Examples and Comparative Examples were municipal waste incineration ash, sewage sludge incineration ash, aluminum ash, iron raw materials, clay, and calcium chloride as raw materials, and C ₁₁ A ₇ CaCl ₂ was 19% by weight. ,
A composition containing calcined material and gypsum in which C ₃ S is 50% by weight, C ₂ S is 9% by weight, and C ₄ AF is 8% by weight (gypsum is S
O ₃ / Al ₂ O ₃ molar ratio is 2.0).

The resulting cured inorganic material was cured for one week in an atmosphere of 20 ° C. and a relative humidity of 95%, dried at 45 ° C. for 24 hours, and measured for flexural strength. Table 5 shows the measurement results.

[0037]

[Table 5] Example 4 Comparative Example 4 {Specific gravity (g / cm ³ ) 1.4 1.4 Flexural strength (kgf / cm ² ) 48 12} ━━━━━━━━━━━━━━━━━━━━━━━

In Example 4, an inorganic cured product having higher flexural strength than Comparative Example 4 was obtained. From this, it is possible to provide a hardened inorganic material having high strength by using the heat-treated incinerated ash according to the present invention.

(Example 5 and Comparative Example 5) Diatomaceous earth 100
Parts by weight, 100 parts by weight silica, incinerated ash or calcined ash 100
Parts by weight and 250 parts by weight of slaked lime were put into 1500 parts by weight of water, mixed with a high-speed mixer, and gently stirred for 3 hours while heating to 90 ° C. 5 parts by weight of glass fiber was added to the obtained slurry, and the mixture was stirred for 2 minutes with an omni-mixer.
To obtain a molded body of 23 × 23 × 2 (cm). This molded body is heated at a temperature of 180 ° C. and a pressure of 10 kg.
After reacting for 3 hours under the conditions of / cm ² and drying at 105 ° C. for 24 hours, an inorganic cured product having tobermorite and CSH gel as a matrix phase was prepared. In Example 5, calcined ash was used, and in Comparative Example 5, incinerated ash was used to produce an inorganic cured product. The obtained cured inorganic material is cut into a piece having a length of 20 cm and a width of 4 c.
The bending strength of an inorganic cured product having a thickness of 2 cm and a thickness of 2 cm was measured. Table 6 shows the measurement results.

[0040]

Table 6 Example 5 Comparative Example 5 {Specific gravity (g / cm ³ ) 0.5 0.5 Flexural strength (kgf / cm ² ) 87 29} ━━━━━━━━━━━━━━━━━━━━━━━

In Example 5, an inorganic cured product having higher flexural strength than that of Comparative Example 5 was obtained. For this reason, by using calcined ash, it is possible to provide an inorganic cured product having high strength.

Example 6 and Comparative Example 6 Hemihydrate Gypsum 10
0 parts by weight, 25 parts by weight of slag, incinerated ash or calcined ash 20
Parts by weight and 60 parts by weight of water were mixed, poured into a mold, cured, released from the mold, and dried at 45 ° C. for 24 hours to prepare an inorganic cured product using gypsum as a matrix phase. In Example 6, calcined ash was used, and in Comparative Example 6, incinerated ash was used to produce an inorganic cured product. The obtained cured inorganic material was cut, and the bending strength of the cured inorganic material having a length of 20 cm, a width of 4 cm and a thickness of 2 cm was measured. Table 7 shows the measurement results.

[0043]

[Table 7] Example 6 Comparative Example 6 {Specific gravity (g / cm ³ ) 0.9 0.9 Flexural strength (kgf / cm ² ) 60 17} ━━━━━━━━━━━━━━━━━━━━━━━

In Example 5, an inorganic cured product having higher flexural strength than Comparative Example 5 was obtained. For this reason, by using calcined ash, it is possible to provide an inorganic cured product having high strength.

[0045]

According to the present invention, a large amount of incinerated ash can be used, excellent in various strengths, excellent in safety due to low content of heavy metals and dioxins, and limited in chlorine content. An inorganic cured product that can be used safely and inexpensively for an application is provided.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C04B 28/14 B09B 3/00 ZAB 28/18 303L // (C04B 28/00 7:28 18:10)

Claims (4)

[Claims] 1. An inorganic cured product obtained by firing incinerated ash obtained by firing an object to be incinerated at least once and using it as a part of a raw material. 2. The inorganic cured product according to claim 1, wherein the incinerated material is at least one selected from the group consisting of municipal waste and sewage sludge. 3. The inorganic cured product according to claim 1, wherein at least one selected from the group consisting of cement hydrate, gypsum and calcium silicate is used as a matrix phase. 4. The inorganic cured product according to claim 3, wherein the matrix phase of the inorganic cured product is formed by curing a hydraulic composition having the following requirements: municipal waste incineration ash and sewage sludge incineration ash. A hydraulic composition comprising at least one calcined product selected from the group, wherein C ₁₁ A ₇ CaCl ₂ is 10%.
Comprising 40 wt%, and comprises a baked product and gypsum containing one or more selected from the group consisting of C ₂ S and C ₃ S.