WO1997012697A1 - Incineration residue solidifying agent and method for solidifying - Google Patents

Abstract

A solidifying agent used to solidify incineration residue, such as ash and soot remaining in an incinerator of a waste incineration plant, and a method of solidifying incineration residue. The solidifying agent comprises 0.1-29 wt.% cement and 71-99.9 wt.% admixture having a latent hydraulicity or pozzolanic activity, and the solidifying method comprising the steps of mixing 10-70 wt.% this solidifying agent with 30-90 wt.% incineration residue, and molding the resultant mixture with a required quantity of water thereto.

Description

 Description Solidification agent for incineration residue and method for solidifying incineration residue

 TECHNICAL FIELD The present invention relates to a solidifying agent for solidifying incineration residues such as incineration ash and dust generated in an incinerator such as a waste incineration plant and a method for solidifying incineration residues. Background art

 Cadmium (Cd) and lead (Pb) are included in the incineration residue such as incineration ash generated when industrial waste and municipal garbage are incinerated and dust collected by electric dust collectors. ) And other harmful heavy metals, especially when the amount of harmful substances eluted is higher than the standard value when landfilled. It is stipulated by law that it must be disposed of before it is dissolved.

 In order to solidify the incineration residue, chemicals such as chelate and various cement-based solidifying agents have been proposed, and various methods for solidifying the incineration residue using the bracketing agent have been proposed. I have.

On the other hand, at present, the above-mentioned incineration residue generated when incinerating industrial waste and municipal trash is landfilled at a managed final disposal site. It is enormous and is said to be 500,000-600,000 tons per year nationwide, and the shortage of disposal sites is a problem. Therefore, one of the solutions is to use incineration residue as a solidifying agent. There is a growing demand for recycling and reusing it in civil engineering materials. Conventional techniques for solidifying such incineration residues include, for example, JP-A-61-133186, JP-A-5-309358, and JP-A-5-33956. There is one disclosed in Japanese Patent Application Publication No. 1118087.

According to the prior art disclosed in Japanese Patent Application Laid-Open No. 61-133186, the carbon content of incinerated ash, starchy substances, proteins, and the like are reduced by chemicals such as aluminum chloride. After gelling, the cement is solidified with a cement-based solidifying agent. However, according to this conventional technique, the strength of the solidified body is extremely low (curing for 8 days, uniaxial compressive strength of 1.5). 7 kg / cm ² ), and no data on the effect of preventing harmful substances from being eluted is unknown.

 Further, the prior art disclosed in Japanese Patent Application Laid-Open No. 5-309356 discloses a method of treating incinerated ash which is stabilized with sulfuric acid and then solidified with cement such as blast furnace cement. However, since the purpose of the treatment is landfill disposal at the final disposal site, the strength of the solidified material and the ability to prevent heavy metals from eluting are extremely low (the elution amount of? 1: 2111).

Further, the prior art disclosed in Japanese Patent Application Laid-Open No. H11-18787 discloses that a hydrothermally reactive powder component is combined with an excess hydrated lime due to hydration of cement by a hydrothermal reaction. Is a solidification method that uses the function of reducing the PH value, but because it is mainly hardened by a hydrothermal reaction, the heating process using steam in an autoclave is used as the hardening process. Pressure was required, and the production cost increased. Furthermore, the ability to prevent heavy metal elution is low, and the elution amount is only 0.02 ppm with respect to the soil environmental standard (less than 0.001 ppm for Pb). Outgoing prevention ability was insufficient.

 In addition, blast furnace cement mixed with blast furnace slag has been used as a solidifying agent as a solidifying agent instead of cement because of cost reduction, heat generation during hydration, and low corrosion.

 However, admixtures that exhibit latent hydraulic properties and pozzolanic activity, such as blast furnace slag, reduce the amount of hydroxide ions in the solidified body at normal temperature and pressure, and actively use this function to reduce pH. In the past, there has been no example of a solidifying agent that trawls to improve the effect of preventing dissolution of amphoteric metals such as lead and the mechanical strength.

Their to, in a conventional method for processing ash, the strength necessary for landfill disposal landfill (uniaxial compressive strength 1 0 kg / cm ² or higher) and elution preventing property (the landfill reference P b In most cases, the purpose is to obtain solidified solids of 3 ppm or less. Even if recycling of civil engineering materials is required, the soil environmental standards (0.0 ppm in the case of Pb) ) And high strength (uniaxial compressive strength of 50 to 100 kg / cm ² or more) were not found.

 At present, clear environmental standards for recycled waste products have not been legalized, but due to environmental considerations, local governments and other governments should use the soil environmental standards as a guide for civil engineering materials. It has become to.

In addition, when the above incineration residue is cured with a solidifying agent containing water such as cement, unreacted aluminum and aluminum compound contained in the incineration residue react with calcium hydroxide, water and the like. As a result, a gas such as hydrogen gas is generated, and the above-described solidification is inhibited or the strength is reduced. Some incineration residues, especially incineration ash, contain organic impurities such as tannic acid and humic acid. When incinerated ash containing organic impurities is solidified by cement, amorphous substances are formed around the unhydrated particles, and these substances are adsorbed on the surface of the cement particles by polarity. Or a bond with Ca ⁺⁺ to form a coating, which inhibits the hydration reaction of the cement and lowers the strength after solidification, so that a high-strength solid could not be obtained.

 On the other hand, in order to obtain a high-strength cement solid of the incineration residue, a prior art in which the incineration residue before kneading with the solidifying agent is pre-treated is disclosed in Japanese Patent Laid-Open No. 5-31. It is disclosed in Japanese Patent Publication No. 780/1983 and Japanese Patent Publication No. 58-49319 / 1988.

The Hei 5 - 3 1 7 8 3 the prior art shown in 0 JP, heated over 1 minute baked却灰at 4 0 0 ^e C or higher, or in pairs to 5 to 1 5 weight ash % Water is added, kneaded, and then cooled. This is because the heating of the incinerated ash by heating at a predetermined temperature or higher converts the exothermic substance into a substance that does not generate heat, and the addition of a predetermined amount of water generates heat and allows it to cool. The reaction is terminated in advance to suppress the heat generated during solidification. As a result, heat generation during cement solidification and generation of cracks due to the heat generation are prevented, and the effect of obtaining a high-strength solidified body is obtained.

In addition, the prior art disclosed in Japanese Patent Publication No. 58-49319 discloses a method in which water and caustic aluminum are added to incinerated ash to cause a pressurized contact reaction, resulting in a temperature of 100 ° C or more. This causes a hydrothermal reaction, which generates slurries and thereby slurries and expands, thereby solidifying the cement contained in the incineration ash. It emits and inactivates components (mainly hydrogen and carbon monoxide) that interfere with the environment.

 By the way, in the prior art disclosed in Japanese Patent Application Laid-Open No. Hei 5-3-1780, no consideration has been given to preventing the outflow of harmful substances such as heavy metals. It was unclear about the safety of using the solidified body for civil engineering materials.

 Also, in the prior art disclosed in Japanese Patent Publication No. 58-49319, since water and caustic alkali are used for heating, handling of the caustic alcohol is troublesome. There was also danger. Through various experiments, the present inventors have found that incineration residues such as incineration ash and dust and the like can be solidified while achieving both mechanical strength and heavy metal elution prevention properties, and a caustic alkali We invented a method for solidifying incineration residues that enables safe operation without using such chemicals.

Disclosure of the invention

 It is known that the elution amount of heavy metals such as Cd and Pb contained in the incineration residue such as incineration ash and dust greatly depends on the pH of the solidified material. FIG. 1 shows an example of the relationship between the pH of a solidified product in a solution and the solubility of the heavy metal. In the figure, a shows the relationship between Cd and b, the solubility of Pb with respect to pH. From this figure, it can be seen that the solubility of Pb in the range of pH 9.5 to 11.5 is It can be seen that the solubility is small, but large before and after this, especially the solubility on the alkaline side where the pH exceeds about 12 is markedly large.

When the incineration residue is solidified with a cement-based solidifying agent, the solidified solution generally shows strong alkali, so elution of amphoteric heavy metals such as Pb may occur. The main problem is that if there is a solidifying agent that exhibits mechanical strength while keeping the pH low, it is possible to achieve both the above-mentioned mechanical strength and anti-elution properties.

 The present inventors have found that an admixture exhibiting latent hydraulic properties, such as blast furnace slag, fly ash, and pozzolan, or pozzolanic activity has the effect of reducing hydroxide ions (OH-) during hardening by adding water. Attention was paid to mixing hydraulic cement and these admixtures in a certain ratio, adding an appropriate amount of water, kneading the mixture, and then molding at room temperature by a molding method such as extrusion molding or compression molding. Thus, it has been found that a solidified body that can prevent the dissolution of Cd and Pb and the like at the same time and has a mechanical strength that can be recycled for civil engineering materials and the like can be obtained.

 That is, the first embodiment of the solidifying agent for incineration residues according to the present invention comprises: cement: 0.1 to 29 wt%;

 Additives with latent hydraulic or pozzolanic activity

 : 7 1 to 9 9.9 w t%

 The solidifying agent is obtained by mixing the solidifying agent and the incineration residue at a predetermined mixing ratio, kneading the mixture by adding a necessary amount of water, and molding.

In this solidifying agent, the pH of the solidifying agent greatly depends on the blending ratio of cement (Portland cement) showing a strong alkali, and therefore, the elution amount of heavy metal is reduced by the incineration residue and solidifying agent. The composition of the incineration residue and the solidifying agent can be considered independently, since the mixing ratio is not significantly affected. As the compounding ratio of the solidifying agent, an admixture exhibiting latent hydraulic property or pozzolanic activity, such as blast furnace slag, does not exhibit curability alone, but calcium hydroxide (C) formed when cement hardens ( C a (OH) 2) shows curability, so a minimum of about 0.1 wt% cement, alkali such as calcium hydroxide, or a curing stimulant such as sulfate is required. Becomes

 Also, the mechanical strength is improved as the amount of cement is increased, but the pH is also increased at the same time, so there is an upper limit to the proportion of cement. According to various experiments by the present inventors, it has been found that when the content exceeds 29 wt%, the amount of heavy metals such as Pb eluted increases in many cases, exceeding the environmental standard.

 In addition, when the cement containing the admixture exhibiting latent hydraulic properties or pozzolan activity, such as blast furnace slag, fly ash and pozzolan, is used as the cement in the above solidifying agent. The composition at is as follows.

 That is, the second embodiment of the solidifying agent for incineration residues according to the present invention has latent hydraulicity or pozzolanic activity.

 Mixed cements containing the indicated admixtures: 0.1 to 97 wt%,

 Shows latent hydraulic or pozzolanic activity

 Admixture: 3-99.9 wt%

 A solidified body is obtained by mixing this solidifying agent with the incineration residue at a predetermined compounding ratio, adding a necessary amount of water, kneading, and molding.

When a cement containing an admixture exhibiting latent hydraulic properties or pozzolanic activity is used in place of the cement in the solidifying agent as described above, this cement is used as the portland cement. Unlike mortars, it already contains admixtures that exhibit potential hydraulic properties such as blast furnace slag, or pozzolanic activity. The upper limit of the amount of leveraged cement is increased, whereas the lower limit of the amount of admixture is reduced.

 Regarding the compounding ratio of the admixture exhibiting latent hydraulicity or pozzolanic activity in the solidifying agent, the total amount of the admixing agent in the solidifying agent is a problem, and the amount of the admixing agent is determined by the amount of the mixed cell used. It can be obtained by converting to the case where the above Portland cement is used based on the component ratio of the ment.

 The following shows conversion examples of mixed cement and admixture in the solidifying agent when blast furnace cement is used as the mixed cement. The blast furnace cement is a mixed cement of a boltland cement and a blast furnace slag, and the mixing ratio is determined by JIS as shown in Table 1 below. .

 table 1

(Conversion example 1)

 When the composition of the solidifying agent is Portland cement 29 wt% and blast furnace slag 7 iwt%, the above Portland cement is replaced with blast furnace cement (class C). The conversion example of the mixing ratio of blast furnace cement and blast furnace slag is shown below.

Blast furnace cement (Class C) is, for example, a mixture of 30 wt% of Portland cement and 70 wt% of blast furnace slag, so it is contained in the blast furnace cement. Blast furnace so that the cement By adjusting the ratio of cement, an equivalent solidifying agent can be obtained.

 That is, assuming that the blast furnace cement ratio is Xwt% and the ratio of the added blast furnace slag is Ywt%, the total cement content is

 X X (30/100) = 29 (wt%),

 The blast furnace slag included in the whole is

 Y + X X (70/100) = 71 (wt%)

 And

 Blast furnace cement ratio X w t% = 97 w t%,

 Blast furnace slag ratio Y w t% = 3 w t%

 Can be converted to

 (Conversion example 2)

 When the composition of the solidifying agent is 0.1 wt% of Portland cement and 99.9 wt% of blast furnace slag, the above Portland cement is blast furnace cement (Class A The following is an example of the conversion of the blending ratio of blast furnace cement and blast furnace slag when this is replaced with).

 Blast furnace cement (species) is a mixture of Portland cement (95 wt%) and blast furnace slag (5 wt%) as an example, so it is contained in the blast furnace cement. If the proportion of the blast furnace cement is adjusted so that the cement content is the same, an equivalent solidifying agent can be obtained.

 That is, assuming that the blast furnace cement ratio is Xwt% and the ratio of the added blast furnace slag is Ywt%, the total cement content is:

 X X (95/100) = 0.l (w t%),

 The blast furnace slag included in the whole is

 Y + X X (5/100) = 99.9 (wt%)

And Blast furnace cement ratio X wt% = 0.llwt%,

 Blast furnace slag ratio Y wt% = 9 9.8 9 w t%

 Can be converted to

 (Conversion example 3)

 The fly cement is a mixture of Portland cement and fly cement, and the mixing ratio is as shown in Table 2 below in JIS. It is decided.

 Table 2

ま た、 シ リ カセメ ン ト はポル ト ラ ン ドセメ ン ト と ポゾラ ン寺の ゲイ酸質混和材の混合セ メ ン ト であ り 、 その配合比率は同様に下 記表 3 に示すよう に決め られている。

Also, silica cement is a mixed cement of Portland cement and a gay acid admixture from Pozzolan temple, and the compounding ratio is also as shown in Table 3 below. It is decided.

 Table 3

固化剤の組成が、 ポル ト ラ ン ドセメ ン ト 2 9 w t %、 ゲイ酸質 混和材 7 1 w t %である場合について、 上記ポル ト ラ ン ドセメ ン トをシ リ カセメ ン ト （ C種） に置き換えた と きの シ リ カセメ ン ト とゲイ酸質混和材の比率の換算例を以下に示す。

When the composition of the solidifying agent is Portland cement 29% by weight and gay acid admixture 71% by weight, the above Portland cement is silica cement (Class C). The following shows an example of conversion of the ratio of silica cement to a gay acid admixture when replacing with

Silicon cement (Class C) is an example of Portland cement. 30 wt% and 70% by weight of gay acid admixture are mixed, so adjust the ratio of silica cement so that the cement content in silica cement is the same. Then, an equivalent solidifying agent can be obtained. In other words, assuming that the silica cement ratio is X wt% and the ratio of the added gaymic admixture is Y wt%, the total cement content is

X X (30/100) = 29 (wt%),

 The gay acid admixture contained in the whole is

 Y + X X (70/100) = 71 (; wt%)

 Becomes

 Silicon cement ratio X w t% = 96.7 w t%,

 Gay acid admixture ratio Y w t% = 3.3 w t%

 Can be converted to

Et al is, the incineration residues, roadbed Ya various blocks, etc., to recycle to the civil engineering materials that require mechanical strength of the uniaxial compressive strength of about 5 0~ 1 0 0 kg / cm 2 In one of the two types of solidifying agent,

 Incineration residue 30 to 90 wt%,

 Solidifying agent 10 to 70 wt%

 The mixture is mixed at the mixing ratio described above, a necessary amount of water is added, the mixture is kneaded, and a solid is obtained by molding.

Solidified body formed in this way at 2 8 days curing (room temperature, ordinary curing under atmospheric pressure), and a uniaxial strength 5 0~ 1 0 0 kg / cm 2 or more, the Environment Agency Notification No. 1 3 As a result of a dissolution test based on the above, the Pb elution amount was less than 0.01 ppm (soil environmental standard).

The compounding ratio of the incineration residue and the solidifying agent is as follows: There is no problem in terms of mechanical strength and elution prevention, but the recycling rate of incineration residue, which is a raw material as a recycled material, decreases, so the processing cost may increase. Even from this point of view, it is generally considered that the upper limit of the compounding ratio of the solidifying agent is about 70 t%.

Regarding the minimum mixing ratio of the solidifying agent, the mechanical strength of the solidified product decreases as the amount of the solidifying agent decreases with respect to the incineration residue as a raw material. According to various experiments by the present inventors, when the mixing ratio of the solidifying agent is 10 wt% or less, the mechanical strength of the solidified material is often reduced to that of recycled materials such as civil engineering materials. island below the uniaxial compression strength 5 0 kg / cm ² is an eye depreciation of the required mechanical strength Te intends.

 Therefore, by solidifying the incineration residue for recycling by using the solidifying agent blended as described above, this incineration residue is eluted with heavy metals that clear environmental standards. It can be made into a solid with prevention.

 That is, the first embodiment of the method for solidifying incineration residues according to the present invention comprises the following:

 Incineration residue 30 to 90 w t%

 Solidifying agent 10 to 70 wt%

 As a result, it was possible to obtain a solidified material having a strength that can be used as a recycle material such as a civil engineering material.

In the second embodiment of the method for solidifying incineration residues according to the present invention, the incineration residues are adjusted to have a water content of 5 to 35 wt, and then treated at a temperature of 40 to 100 and a humidity of 50 to 50 wt. Steam treatment is performed for 15 minutes to 4 hours in a steam atmosphere controlled to 100%, and then the mixture is kneaded with a solidifying agent such as cement to form and solidify. In addition, stirring is not always required during steam treatment, but stirring may provide a higher effect.

 In the second embodiment, the incineration residue is subjected to steam treatment to promote the hydration reaction (Pozzolan reaction) of the activated silica in the incineration residue, to increase the particle size of the incineration residue itself, and to increase the aggregate. And the strength is increased. In this case, an oxide film is formed on the surface of the reactant to prevent the reaction, or the gas generation reaction between the incineration residue and the alkali is promoted to complete the reaction.

According to the method for solidifying incineration residues that have been subjected to moisture adjustment and steam treatment as described above, the incineration residues are kneaded with a solidifying agent such as cement, molded and cured for a predetermined time. resulting et is Ru solidified body Ri Do uniaxial compressive strength 1 3 0 kg / cm ^2, the teeth such as the this using a special chemicals, H of sufficient strength as the re cycles material such as civil engineering materials You get the body.

 In the third aspect of the method for solidifying incineration residues according to the present invention, the incineration residues are heated to a treatment temperature of 250 to 900 to decompose organic impurities in the incineration residues, and then the The moisture of the incineration residue is adjusted to a water content of 5 to 3 δ wt ° o, and then the steam atmosphere is controlled at a treatment temperature of 40 to 100% and a humidity of 50 to 100%. The mixture is steamed for 15 minutes to 4 hours while being stirred at, and then kneaded with a solidifying agent such as cement to form and solidify.

In the third embodiment, the organic residue in the incineration residue is removed by decomposition or the like by subjecting the combustion residue to heat treatment at 250 to 900. Then, by steaming the incineration residue, the hydration reaction (Pozzolan reaction) of activated silica in the incineration residue is promoted, and the particle size of the incineration residue itself and the strength as aggregate are increased. Will be increased. And At this time, an oxide film is formed on the surface of the reactant to prevent the reaction, or the gas generation reaction between the incineration residue and the alkali is promoted to complete the reaction.

 According to the method for solidifying the incineration residue that has been subjected to the heat treatment as described above, the water content has been adjusted, and then the steam treatment has been performed, even if the incineration residue containing organic impurities is used for civil engineering materials, etc. A high-strength solid can be obtained as a recycled material.

 It goes without saying that the first and second aspects of the solidifying agent for incineration residues according to the present invention can be used in the method for solidifying incineration residues according to the present invention. BRIEF DESCRIPTION OF THE FIGURES

 The invention will be better understood from the following detailed description and the accompanying drawings illustrating an embodiment of the invention. The embodiments shown in the accompanying drawings are not intended to specify the invention, but merely to facilitate explanation and understanding.

 In the figure,

 FIG. 1 is a diagram showing the relationship between pH and the solubility of heavy metals (: C d, P b).

 FIG. 2 is an explanatory view showing a second embodiment of the method for solidifying incineration residues according to the present invention.

 FIG. 3 is an explanatory view showing a third embodiment of the method for solidifying incineration residues according to the present invention.

Figure 4 is a diagram showing the uniaxial compression strength against the initial moisture content of incinerated ash during steam treatment. Figure 5 is a graph showing the uniaxial compressive strength of incinerated ash against the steam treatment temperature.

 Fig. 6 is a graph showing the uniaxial compressive strength of incinerated ash against steam treatment humidity.

 Fig. 7 is a graph showing the uniaxial compressive strength of incinerated ash against steaming time.

 FIG. 8 is a diagram showing the uniaxial compressive strength of incinerated ash with respect to the heat treatment temperature.

 FIG. 9 is a graph showing the uniaxial compressive strength of incinerated ash with respect to the heat treatment time. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of the solidifying agent and the solidifying method according to the present invention will be described based on some experimental examples and examples.

 (Experimental example 1)

 Incinerated ash 90 wt%.

Solidifying agent 100 wt ¾ Composition: Portland cement 28 wt ° o Blast furnace slag 72 2 wt% Add an appropriate amount of water to the above mixture, knead, and add 100 kg / cm ² Press molding under pressure

 2 8 days curing (normal curing under normal temperature and pressure)

Uniaxial compressive strength 5 4 kg / cm ²

A lead elution amount of 0.008 ppm (a dissolution test based on the Notification of the Environment Agency No. 13) was obtained. (Experimental example 2)

 Incineration ash 9 2 wt%

 Solidifying agent 8 wt% Composition: Portland cement 30 wt%

Blast furnace slag 7 0 wt% above formulation, and kneading the resulting mixture together with a suitable amount of water, 1 0 0 This filtrate that by applying a pressure of kg / cm ² by press molding

 2 8 days curing (normal curing under normal temperature and pressure)

Uniaxial compressive strength 4 8 kg / cm ²

A lead elution amount of 0.011 ppm ⁽ : a dissolution test based on the Environment Agency Notification No. 13) was obtained.

 (Experimental example 3)

 Incinerated ash 7 0 w t%

Solidifying agent 30 wt ^α組成 Composition: Portland cement 1 wt%

Blast furnace slag 9 9 wt ¾ above formulation, and kneading the resulting mixture together with a suitable amount of water, 1 0 0 This filtrate that by applying a pressure of kg / cm ² by press molding

 2 8 days curing (normal curing under normal temperature and pressure)

Uniaxial compressive strength 8 5 kg Z cm ²

 A lead elution amount of 0.002 ppm (dissolution test based on Notification No. 13 of the Environment Agency) was obtained.

 (Experimental example 4)

 Incinerated ash 80 wt%

Solidifier 20 wt ⁰ 'ό Composition: Blast furnace cement (Class B) 50 wt% Blast furnace slag 50 wt% An appropriate amount of water was added to the above mixture, kneaded, and press-molded under a pressure of 100 kg / cm ^2.

 2 8 days curing (normal curing under normal temperature and pressure)

Uniaxial compressive strength 1 1 7 kg / cm ²

 A lead elution amount of 0.009 ppm (dissolution test based on Notification No. 13 of the Environment Agency) was obtained.

 (Experimental example 5)

 Incinerated ash 6 5 wt%

Solidifying agent 35 wt <% Composition: silica cement (: Class C) 40 wt% silica fume 60 wt% To the above mixture, add an appropriate amount of water and knead. this filtrate and was press-molded by applying a pressure of kg / cm ²

 2 8 days curing (normal curing under normal temperature and pressure)

Uniaxial compressive strength 1 3 2 kg / cm ^:

 A lead elution amount of 0.009 ppm (dissolution test based on Notification No. 13 of the Environment Agency) was obtained.

 (Experimental example 6)

 Incinerated ash 6 0 w t%

 Dust 20 w t%

Solidifying agent 20 wt% Composition: Portland cement 0.3 wt% Blast furnace slag 99.7 wt% Add an appropriate amount of water to the above mixture, knead, and add 100 kg / cm ^Two Press molding

 2 8 days curing (normal curing under normal temperature and pressure)

Uniaxial compressive strength 1 2 1 kg / cm ²

 A lead elution amount of 0.009 ppm (dissolution test based on Notification No. 13 of the Environment Agency) was obtained.

 (Experimental example 7)

 Incinerated ash 7 0 w t%

Solidifying agent 30 wt ⁰ ό Composition: Portland cement 1 wt%

Blast furnace slag 9 4 wt% anhydrite 5 wt% above formulation, and kneading the resulting mixture together with a suitable amount of water, 1 0 0 This filtrate that by applying a pressure of kg / cm ² by press molding

 2 8 days curing (normal curing under normal temperature and pressure)

 Uniaxial compressive strength 1 200 kg / c

A lead elution amount of 0.02 ppm (a dissolution test based on the Notification of the Environment Agency No. 13) was obtained. Among the above Experimental Examples, the mixing ratio of solidifying agent against the ash to 1 0 wt% or is less than 8 wt ^0, the mixing ratio Pol preparative run-de Se e n t in solidifying agent 3 In Experimental Example 2 in which the content was 0 wt%, the strength of the solidified body did not reach 50 kg / cm ² and there was a problem in strength. In addition, the elution prevention of lead slightly exceeded the standard.

However, the mixing ratio of the solidifying agent is set to 10 wt% or more (that is, In the first embodiment of the method for solidifying incineration residues according to the present invention, wherein the mixing ratio of the incinerator residue and the incineration residue is 30 to 90 wt% of the incineration residue and 10 to 70 wt% of the solidifying agent). In other experimental examples in which the mixing ratio of Portland cement in the solidifying agent was set to 29 wt% or less, the mechanical strength of the solidified body exceeded 50 kg / cm- In addition, the expected strength was obtained. In addition, the elution amount of lead (heavy metal) was less than the environmental standard value, respectively, and the elution prevention of heavy metal was confirmed. In addition, when the mixing ratio of the solidifying agent is set to 10 wt ° ₀ or more and the portland cement content in the solidifying agent is set to 0.1 to 29 wt%, the latent water A small amount of admixture showing hard or pozzolanic activity

As shown in Experimental Example 7 above, the desired strength and heavy metal elution prevention properties were obtained even with the addition of admixtures (about several percent) such as gypsum and water reducing agents.

 In addition, cement admixtures such as gypsum and water reducing agents are often added in small amounts to improve workability and improve the quality of solidified products. Even in the solidifying agent according to the present invention, the desired performance of the solidifying agent can be obtained even if these cement admixtures are added within the range of the present invention.

 By the way, gypsum may generate ettringite when the cement undergoes a hydration reaction, thereby improving strength. Gypsum also has the effect of delaying the hydration of cement.

In all of the above experimental examples, among the harmful substances regulated by the soil environmental standards, all substances other than Pb were below the standard value. In all of the above experimental examples, 20 wt% of water was added to the total weight of the incinerated ash and the solidifying agent during kneading. The optimum amount of water to be added depends on the shaping method. 10 to 50 wt% is desirable.

 Next, another embodiment of the method for solidifying incineration residues according to the present invention will be described below.

FIG. 2 shows a second embodiment of the method for solidifying incineration residues according to the present invention. According to is this, if it is solidified by untreated or or cell e n t, using the uniaxial compressive strength of 5 kg / cm ^{2 (2} 8 days curing) there is only ash (original ash), this Put it into hopper 1, apply it to grizzly feeder 2, and remove large metal such as empty cans with primary magnetic separator 3. Next, small metals are removed by the secondary magnetic separator 4, and then the non-ferrous metals are removed by a non-ferrous separator 5 such as an aluminum separator, and the particle size is adjusted by passing through a 4 mm sieve 6. I do. Then, after the incinerated ash whose particle size has been adjusted cools down, water is added by a water conditioner 7 to adjust the water content to 10%. Then, let it stand for 24 hours to allow the water to adjust to the ash.

Thereafter, the mixture is stirred for 2 hours in a steam atmosphere at a temperature of 100 and a humidity of 98% by a rotary steam processor 8. Next, the incinerated ash subjected to the steam heating treatment is mixed in a kneader 9 with 80 wt% of the incinerated ash and 20 wt% of the solidifying agent (composition: 50 wt% of blast furnace cement B, 50 wt%, blast furnace slurry). The mixture is kneaded at a ratio of 50 wt% j, and the mixture is applied to a molding machine 10 and compression molded at a surface pressure of 100 kg / cm ² to obtain a solid 11. After curing for 28 days, the unconfined compressive strength was measured to be 130 kg / cm ² .

FIG. 3 shows a third embodiment of the method for solidifying incineration residues according to the present invention. This is due to the fact that it contains organic impurities, so that the treatment according to the second embodiment, that is, the steam treatment and then the solidification in cement However, incineration ash with a uniaxial compressive strength of 5 kg / cm ² or less (cured for 28 days) was pretreated as follows and then solidified with a solidifying agent. In the description of the example, the same portions as those of the second embodiment shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

 The above incinerated ash is put into the hopper 1, passed through the grizzly feeder 2, and the large metal is removed by the primary magnetic separator 3. Then, the incinerated ash is removed by the tiller type heat treatment machine 12. Is heated at 400 for 2 hours.

 After that, the small metal is removed by the secondary magnetic separator 4, then the non-ferrous metal is removed by the non-ferrous separator 5, and the particle size is adjusted by passing through a 4 mm sieve 6. Then, after the incinerated ash whose particle size has been adjusted cools down, water is added by a water content adjuster 7 so that the moisture content of the incinerated ash becomes 10%.

Thereafter, the mixture is stirred for 2 hours in a steam atmosphere at a temperature of 100 and a humidity of 98% in a rotary steam processor 8. Then, the incinerated ash subjected to the steam heating treatment is mixed in a kneader 9 with 80 wt% of incinerated ash and 20 w% of solidifying agent (composition: 50 wt% of blast furnace cement, class 50 wt%, blast furnace slag). The mixture is kneaded at a ratio of 50 t% j, and the mixture is applied to a molding machine 10 and compression molded at a contact pressure of 100 kg / cm ² to obtain a solid 11. After curing for 28 days, the unconfined compressive strength was measured to be 13.6 kg / cm ² .

 In the second and third embodiments, the reaction mechanism of the incinerated ash in the rotary steam processor 8 is not necessarily clear, but it is considered that the following reactions are mainly involved.

(1) C0 + Si02 + H2〇 → xCaO-ySi2〇2. H2〇 and other hydration reactions (: pozzolanic reaction) Strength Improve.

 (2) 2A1 + 6H20 → 2A1 (OH) 3 + 3 An oxide film is formed on the surface of the active component to inactivate it by the reaction of {2} and prevent gas generation.

 (3) The gas reaction such as 2A1 + 2NaOH + 2H20 → 2NaA102 + 3H2 † is promoted to complete the reaction before kneading with the solidifying agent. Further, as a reaction in the heat treatment in the rotary heat treatment device 12 in the third embodiment,

 C X H y 0 z — X C 02+ y / 2 H 20 is performed, and organic impurities (C X H y 0 z) are oxidatively decomposed.

The results of examining the strength of the solidified body after forming under various conditions before steaming in the third embodiment in which the incinerated ash was heated, moisture-adjusted, and then steamed are shown below. In the following, the condition range refers to a range in which the unconfined compressive strength of the solidified body is 50 kg / cm ² or more, and the experimentally preferable range refers to a range in which the highest strength is obtained.

Fig. 4 shows the uniaxial compressive strength against the initial moisture content of the incinerated ash during steam treatment.After the incinerated ash was heated at 400 = C for 2 hours, the water content was adjusted by the water conditioner 7. Then, each incineration ash having an initial moisture content of 5100, 20 and 35% at the time of steam treatment was subjected to 100 hours, steamed at a humidity of 98% for 2 hours, and then added to each incineration ash. It shows the uniaxial compressive strength (cured for 28 days) of kg / cm ² obtained by kneading and molding 0 wt% cement. As can be seen from this figure, the initial moisture content of the incineration ash during steam treatment is 5 to 35%, and the experimentally preferred range is 10 to 20%. . Fig. 5 shows the uniaxial compressive strength of the incinerated ash against the steam treatment temperature.After heating the incinerated ash at 400 ° C for 2 hours, the moisture content was adjusted to 10% and the steam temperature was adjusted to 20%. , 40, 85, and 100, respectively, show the uniaxial compressive strength of the solidified material when steamed at 98% humidity for 2 hours. As can be seen from this figure, the condition range of the steam temperature during steam processing is 40 or more, and the experimentally preferable range is 60 to 100.

6, since indicates the uniaxial compressive strength of the ash for steaming humidity and ash 4 0 ^0; after 2 hours of heat treatment in C, and adjusted to a water content 1 0 ¾, then the temperature is 8 5 It shows the uniaxial compressive strength of the solidified material when treated for 2 hours at 30 ° C, 50%, 80%, and 98% steam at ° C. As can be seen from this figure, the condition range of the humidity of the steam atmosphere is 50 ° C. or more, and the experimentally preferable range is 85 to 100%.

7, since shows the uniaxial compressive strength of the ash to the steam treatment time, ash and heat treatment for 2 hours at 4 0 0 hand, adjusting the water content of the ash after the heat treatment 1 0 ^Q 0 After that, it shows the uniaxial compressive strength of each solidified body when treated with steam at a temperature of 100 and a humidity of 98% for 15 minutes, 2 hours and 4 hours, respectively. As can be seen from this figure, the range of conditions between steam treatments is 15 minutes or more, and the experimentally preferred range is 2 to 4 hours.

Fig. 8 shows the uniaxial compressive strength of the incinerated ash with respect to the above heat treatment temperature, and the untreated and heated temperatures were 100, 200, 250, 300, 400, 600. 0 0, 8 0 0, 9 0 0. C for 2 hours, and then incinerate each ash with initial water content of 10%, 100 ⁼ C, Shows the uniaxial compressive strength of the solidified body when steamed at 98% humidity for 2 hours. Conditions range This figure 2 5 0 ^S C or higher, preferred correct range experimentally was this Togawaka' is 2 5 0-9 0 0 Hand.

9, since shows the uniaxial compressive strength of the ash to the heat treatment time, incineration ash at 4 0 0 ⁵ C, 3 0 minutes, 2 hours, heat treated respectively 4 hours, the initial respective ash Shows the uniaxial compressive strength of the solidified product when steamed at a moisture content of 100%, 100, 2 hours, and a humidity of 98%. As can be seen from the figure, the condition range of the heat treatment time is 15 minutes or more, and the experimentally preferable range is 2 to 4 hours.

 The present invention has been described with reference to exemplary embodiments, or various changes, omissions, and additions can be made to the disclosed embodiments without departing from the spirit and scope of the present invention. That is obvious to those skilled in the art. Therefore, the present invention should not be construed as being limited to the above-described embodiments, but as including the scope defined by the elements recited in the claims and their equivalents. Must.

Claims

The scope of the claims  1. Cement: A solidifying agent for incineration residues, which is composed of 0.129 wt% of admixture and 71 to 99.9 wt% of admixture exhibiting latent hydraulic or pozzolanic activity. 2. Mixed cement containing admixture exhibiting latent hydraulic or pozzolanic activity: 0.1 to 97 wt%, admixture exhibiting latent hydraulic or pozzolanic activity: 3 to 99 A solidifying agent for incineration residues containing 9 wt%. . 3 Seme emissions Application:. 0 1 and ~ 2 9 wt%, have with latent hydraulic miscible material shows the Pozo run-activity:. 7 1 ~ 9 9 9 wt α baked made by blending ο却残渣用Solidifying agent: 10 to 70 wt%  Incineration residue: 30 to 90 wt%  A method to reduce incineration residues by adding the required amount of water and forming. 4. Mixed cement containing admixture exhibiting latent hydraulic or pozzolanic activity: 0.1 to 97 wt% and admixture exhibiting latent hydraulic or pozzolanic activity: 3 to 99. Solidification agent for incineration residue containing 9 wt <½: 10 to 70 wt <%,  Incineration residue: 30 to 90 wt%  A method of solidifying incineration residues by adding the required amount of water and forming. 5. After adjusting the water content of the incineration residue to a water content of 5 to 35 wt%, perform steam treatment at a treatment temperature of 40 or more for 15 minutes or more, and then A method for solidifying incineration residues, which is kneaded with a solidifying agent for incineration residues to form and solidify. 6. After adjusting the water content of the incineration residue to a moisture content of 5 to 50 w%, the content was reduced to 50 to 100% at a treatment temperature of 40 or more. A method for solidifying incineration residues by steaming for at least 5 minutes while stirring in a steam atmosphere, and then kneading with an incineration residue solidifying agent to form and solidify. 7. The method for solidifying incineration residues according to claim 6, wherein the moisture content of the incineration residues is 10 to 20%. 8. The method for solidifying incineration residues according to claim 5, wherein the treatment temperature is from 60 to 100. 9. The method for solidifying incineration residues according to claim 6, wherein the treatment temperature is 60 to 100 ^: C. 10. The method for solidifying incineration residues according to claim 7, wherein the treatment temperature is 60 to 100 ° C. 11. The method for solidifying incineration residues according to any one of claims 5 to 10, wherein the steam treatment time is 2 to 4 hours. 1 2. Heat the incineration residue at a processing temperature of 250 ° C or more for 15 minutes or more. 2f  The method for solidifying incineration residue according to any one of claims 5 to 10, wherein the incineration residue is subjected to steam treatment after decomposing organic impurities in the incineration residue. 1 3. The incineration residue is heated at a treatment temperature of 250 ° C or more for 15 minutes or more to decompose organic impurities in the incineration residue, and then the incineration residue is subjected to steam treatment. 1. The method for solidifying incineration residues described in 1. '14. The method for solidifying incineration residues according to claim 12, wherein the heat treatment temperature is from 250 to 900. 1. The method for solidifying incineration residues according to claim 13, wherein the heat treatment temperature is 250 to 900 ^; C. 15. 16 6. After adjusting the water content of the incineration residue to a moisture content of 5 to 35 wt%, the temperature was controlled at a treatment temperature of 40 to 100% and a humidity of 50 to 100%. A method of solidifying incineration residue, which is steamed for 15 minutes to 4 hours while stirring in a steam atmosphere, and then kneaded with an incineration residue solidifying agent to form and solidify. 17. The incineration residue is heated to a treatment temperature of 250 to 900 to decompose organic impurities in the incineration residue, and then the incineration residue has a water content of 5 to 35 wt%. Water for 15 minutes to 4 hours while stirring in a steam atmosphere controlled at a processing temperature of 40 to 100 ° C and a humidity of 50 to 100%. Steam treatment, then incineration residue A method of solidifying incineration residues by kneading with a solidifying agent for residue to form and solidify. 18. The method for solidifying incineration residues according to claim 16 or 17, wherein the solidifying agent for incineration residues is cement. 19. The solidifying agent for incineration residue is composed of cement: 0.1 to 29 wt <% and admixture showing latent hydraulic or pozzolanic activity: 71 to 99% by weight. The method for solidifying incineration residues according to claim 16 or 17, wherein the method comprises the steps of: 20. The cement containing the admixture exhibiting latent hydraulic or pozzolanic activity, wherein the solidifying agent for incineration residue has a latent hydraulicity or pozzolanic activity of 0.1 to 97 wt%. The method for solidifying incineration residues according to claim 16 or 17, wherein the admixture is a mixture of 3 to 99.9 wt%. 21. The method for solidifying incineration residues according to claim 5 or 6, wherein the humidity is from 80 to 100%.