JP2007136393A - Treatment method of elution component-containing substance, stabilization material, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment method of elution component-containing substance using substances which may elute lead (Pb), fluorine (F), selenium (S) or the like, as chemical components having the possibility of elution in a using environment, and suppressing these components to a low level causing no problem. <P>SOLUTION: A treating object substance eluting at least one kind of Ca ions, Al ions and S-containing ions in the presence of water, is blended to the elution component-containing substance containing a certain elution components at the ratio of 1-100 mass parts to 100 mass parts of the elution component-containing substance, to form a hydrate containing Ca, Al and S to fix the certain elution components into the hydrate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a treatment method for suppressing the elution of an elution component from an elution component-containing substance, a stabilization material that suppresses the elution of such an elution component, and is suitable for civil engineering construction, and a method for manufacturing the same.

  Various industrial by-products generated in various industries with the development of the industry are increasing year by year. Recently, attempts have been made to use such industrial by-products from the viewpoint of global environmental conservation. For example, it is considered that inorganic substances such as coal ash generated in a thermal power plant, municipal waste molten slag, and incinerated ash molten slag are reused as civil engineering and building materials such as roadbed materials and ground materials.

  However, since such civil engineering and building materials are used in an environment exposed to wind and rain, there is a possibility that specific chemical components contained therein are eluted by moisture. In the case where a chemical component that can be eluted into moisture in this way has a possibility of adversely affecting the surrounding environment, some measures for preventing the chemical component from being eluted are necessary.

  Typical chemical components that may be affected by the surrounding environment include heavy metals such as cadmium (Cd), mercury (Hg), chromium (Cr), lead (Pb), and arsenic (As). Can be mentioned.

  Among these, Cr is contained in high concentration in the effluent of plating factory and tannery factory, as well as on the site where cement is used, such as ready-mixed concrete factory, concrete secondary product factory, dam and tunnel construction site. It may be contained to some extent in the wastewater discharged from the tank. In addition, there are cases of high concentrations in factory sites, etc., from which they may enter groundwater. For this reason, Cr is recognized as the most typical chemical component that may be contained in various industrial by-products, and various techniques for preventing elution of hexavalent Cr from civil engineering and building materials have been proposed.

For example, in Patent Document 1, when a chromium-containing substance such as stainless steel refining slag is used as a civil engineering construction material such as a roadbed material, a blast furnace slag is sprinkled by placing a blast furnace slag as a sulfur-containing slag and sprinkling water over it. Method for preventing elution by reducing and stabilizing hexavalent chromium in a chromic acid compound-containing substance by reducing sulfur (S ²⁻ , S ⁰ , S ₂ O ₃ ²⁻ ) in the elution water Has been proposed.

On the other hand, recently, not only heavy metals as described above, but also chemical components other than heavy metals such as fluorine (F) have been regulated as chemical components that adversely affect the environment. Has proposed a steelmaking slag stabilization treatment technique that is effective to suppress and stabilize fluorine elution from steel-containing slag containing fluorine. This technique fixes F in steelmaking slag as a CaO—Al ₂ O ₃ —F-based hydrate by blending alumina brick scraps, aluminum ash, or the like.

  By the way, in recent years, demands for protection of the global environment and living environment are increasing, and emission regulations of chemical components that may pollute the environment are becoming stricter. For example, in the Basic Environment Law, from the viewpoint of human health protection and living environment protection, among the environmental standards related to water pollution, items related to human health include lead (Pb) other than chromium (Cr) less than 0.05 mg / L. ) Is less than 0.01 mg / L, fluorine (F) is less than 0.8 mg / L, selenium (Se) is less than -0.01 mg / L, and so on. Therefore, materials that satisfy these standards are required for civil engineering and building materials.

However, the above-mentioned Patent Document 1 prevents only the elution of Cr, and does not prevent the elution of other chemical components such as Pb, F, and Se. It only prevents elution, and cannot remove other chemical components such as Se and Pb. In particular, Se is a chemical component that has recently been regulated, and no effective removal measures have yet been proposed.
Japanese Patent Laid-Open No. 11-104699 JP 2000-247694 A JP 2005-132721 A

  The present invention has been made in view of such circumstances, and lead (Pb), fluorine (F), selenium (Se) as chemical components that may be eluted in the use environment when industrial by-products are used as materials. ) And the like, and a treatment method for a substance containing an elution component capable of suppressing elution to a low level without any problem, and a stabilizing material in which the elution of such a substance is stabilized to a level at which there is no problem, and a method for producing the same. The purpose is to do.

  As a result of repeated studies to solve the above-mentioned problems, the present inventors have found that an elution component-containing substance containing an elution component such as Pb, F, and Se contains Ca ions, Al ions, and S in the presence of water. When a predetermined amount of a treatment substance that elutes at least one kind of ion is blended to form a hydrate containing Ca, Al, and S, preferably ettringite and / or kuserite, the elution component is fixed to the hydrate. As a result, the present invention was completed.

  That is, the present invention provides a treatment substance that elutes at least one of Ca ions, Al ions, and S-containing ions in the presence of water with respect to an elution component-containing substance containing a predetermined elution component. It mix | blends in the ratio of 1-100 mass parts with respect to 100 mass parts, forms the hydrate containing Ca, Al, and S, Preferably ettringite and / or a kuserite, The said predetermined elution component is made into the said hydrate. Provided is a method for treating an elution component-containing substance characterized by immobilizing.

  The present invention also provides a method for producing a stabilizing material, characterized by producing a stabilizing material in which the predetermined elution component is fixed to the hydrate and stabilized by the treatment method.

  The present invention further provides a treatment substance that elutes at least one of Ca ions, Al ions, and S-containing ions in the presence of water with respect to an elution component-containing substance containing a predetermined elution component. A hydrate containing Ca, Al, and S, preferably ettringite and / or kuserite is formed, and is blended at a ratio of 1 to 100 parts by mass with respect to 100 parts by mass, and the predetermined elution component is the hydrated Provided is a stabilizing material characterized by being fixed to an object and stabilized.

  In the present invention, examples of the predetermined elution component include Pb, F, Se, Cd, As, B, and Cr (hexavalent). Moreover, coal ash is illustrated as said elution component containing material. Further, examples of the treatment substances include calcium hydroxide, steel slag, ordinary Portland cement, alumina cement, gypsum, waste concrete, aluminum hydroxide, aluminum sulfate, alumina-containing brick, aluminum ash, alumina-containing waste, and sulfur compounds. Is done.

  According to the present invention, a treatment substance that elutes at least one of Ca ions, Al ions, and S-containing ions in the presence of water is added to the elution component-containing substance, and Ca, Al, and S formed at that time are mixed. Since the eluting components are fixed to the hydrate, preferably ettringite and / or kuserite, the elution of Pb, F, Se, etc. can be suppressed to a level that does not affect the environment. For this reason, the stabilization material manufactured by processing in this way can be safely and effectively used as a civil engineering building material such as a roadbed material and a soil improvement material.

Hereinafter, the present invention will be specifically described.
In the present invention, with respect to an elution component-containing substance containing a predetermined elution component, a treatment substance that elutes at least one of Ca ions, Al ions, and S-containing ions in the presence of water is used as 100 mass of the elution component-containing substance. 1 to 100 parts by mass with respect to parts. Thereby, a hydrate containing Ca, Al, and S is formed, and a predetermined elution component contained in the elution component-containing substance is fixed to the hydrate.

  In the present invention, the predetermined elution component is a chemical component that may be eluted in the presence of moisture and may adversely affect the environment. In the present invention, typically, Pb, F, Se, Cd, As, B and Cr (hexavalent) can be mentioned. In the present invention, the elution component-containing substance containing a predetermined elution component is not particularly limited as long as it contains such an elution component, but coal generated as a by-product in a thermal power plant or the like Typical examples include ashes and various slags. Especially, coal ash can be mentioned as a suitable example.

  Coal ash is generated by burning coal in a coal-fired power plant, and is, for example, clinker ash collected from the bottom of a boiler, fine powder (fly ash) collected from an electric dust collector, or the like.

  Examples of various slags include municipal waste melting slag, general waste melting slag represented by incineration ash melting slag, and the like, but are not limited thereto. Of these, municipal waste molten slag is a waste of municipal waste or incinerated ash, which is heated and burned at a very high temperature (over 1200 ° C) with combustion heat or heat energy obtained from electricity. It is a vitreous solidified product that has been cooled after being melted.

  A treatment substance that elutes at least one of Ca ions, Al ions, and S-containing ions in the presence of water is added to the elution component-containing substance. The compounding quantity of the process substance at this time is 1-100 mass parts with respect to 100 mass parts of elution component containing substances. When the treatment substance is less than 1 part by mass, the hydrate is not sufficiently formed, and elution of the predetermined elution component contained in the elution component-containing substance cannot be sufficiently suppressed. This is because the effect of fixing the eluted components is saturated.

  Examples of treatment substances that elute at least one of Ca ions, Al ions and S-containing ions in the presence of water include steel slag, calcium hydroxide, ordinary portland cement, alumina cement, gypsum, waste concrete, aluminum hydroxide, Examples thereof include aluminum sulfate, alumina-containing brick, aluminum ash, alumina-containing waste, and sulfur compounds.

  Among these, calcium hydroxide, steel slag, ordinary Portland cement, alumina cement and waste concrete can function as substances that elute Ca ions in the presence of water. As a substance that elutes Ca ions in the presence of water, in addition to these, a Ca desulfurizing agent and coal ash mixed with a Ca desulfurizing agent can also be used.

  In addition, aluminum hydroxide, aluminum sulfate, the steel slag, the alumina cement, the alumina-containing brick, the aluminum ash, and the alumina-containing waste can function as a substance that elutes Al ions in the presence of water.

  Furthermore, the said aluminum sulfate, gypsum, a sulfur compound, and the said steel slag can function as a substance which elutes S containing ion in presence of water.

  Among the above substances, steel slag can elute any of Ca ions, Al ions, and S-containing ions in the presence of water. Examples of steel slag include converter slag, secondary refining slag, dephosphorization slag, desulfurization slag, electric furnace oxidation slag, and electric furnace reduction slag. Secondary refining slag is a general term for slag that is produced when the molten steel produced from a converter or the like is subjected to treatment such as desulfurization, dephosphorization, and degassing. The electric furnace oxidation slag is slag generated during oxidation refining in which oxygen is blown into molten steel in an electric furnace to oxidize unnecessary components. Further, the electric furnace reducing slag is slag generated when desulfurization is performed in a reduced state in an electric furnace.

Also, ordinary Portland cement is a typical cement is most commonly produced, the main components compounds, silicate tricalcium (3CaO · _SiO 2), dicalcium silicate (2CaO · _SiO 2), aluminate These include tricalcium acid (3CaO.Al ₂ O ₃ ) and iron calcium tetraaluminate (4CaO.Al ₂ O ₃ .Fe ₂ O ₃ ).

Alumina cement is significantly different in chemical composition from the above-mentioned ordinary Portland cement used in civil engineering construction, and its composition is characterized by a large amount of alumina (Al ₂ O ₃ ) and a small amount of CaO.

  In the case of materials other than steel slag, alumina-containing bricks, alumina-containing waste and waste concrete among the processing substances that elute at least one of Ca ions, Al ions and S-containing ions in the presence of water exemplified above The blending amount is preferably about 1 to 60 parts by mass with respect to 100 parts by mass of the elution component-containing substance. Most of the materials other than steel slag, alumina-containing bricks, alumina-containing waste and waste concrete are in the form of fine powder, so if it exceeds 60 parts by mass, the total particle size distribution will increase too much, and civil engineering construction It is not preferable as a material. If the lower limit of 1 part by mass is less than this, the ion elution amount is small as described above, and a stable elution suppression effect cannot be exhibited. More preferably, it is 1-20 mass parts, More preferably, it is 4-16 mass parts.

  As a treatment substance that elutes at least one of Ca ions, Al ions, and S-containing ions in the presence of water, it is preferable to use those having an average particle diameter of about 40 mm or less. This is because when the average particle diameter exceeds 40 mm, Ca ions and the like are not easily eluted into water existing outside the civil engineering and building materials.

  In the present invention, by adding the treatment substance to the elution component-containing substance, a hydrate containing Ca, Al and S, preferably ettringite and / or kuserite, is formed, and the predetermined elution component is added to the water. Fix to Japanese products and suppress the elution of chemical components that adversely affect the environment.

Hereinafter, this point will be described in detail.
The present invention includes a hydrate containing Ca, Al, and S by adding a treatment substance that elutes at least one of Ca ions, Al ions, and S-containing ions in the presence of water to the elution component-containing substance, Preferably, ettringite and / or kuserite is formed, and a small amount of elution component such as Pb, F, Se contained in the elution component-containing substance is adsorbed and fixed to the Ca-Al-S hydrate, and these components are contained. Therefore, the present invention provides a technique for obtaining a stabilizing material in which elution is sufficiently suppressed.

That is, in the study of the present inventors, at least one of Ca ions, Al ions, and S-containing ions is eluted in the presence of moisture with respect to the eluted component-containing substance containing the eluted components such as Pb, F, and Se. when blended with the treated substance to, in the presence of water, Ca, amorphous or hydrate containing Al and S, ettringite _{(Ca 6 Al 2 (SO 4} ) 3 (OH) 12 · 26H 2 O ) and / or Kuzeraito _{(Ca 4 Al 2 (SO 4} ) (OH) 12 · 6H 2 O) was found to be generated. At this time, elution components such as Pb, F, Se, Cd, As, B, and Cr (hexavalent) contained in the elution component-containing substance are fixed to the hydrate by a coprecipitation phenomenon. The coprecipitation phenomenon is a phenomenon in which what should not be precipitated in view of the solubility product is mixed into the precipitate as another precipitate is formed. Here, Pb, F, An elution component such as Se is deposited along with the precipitation of the hydrate. Generally, adsorption is the main component, but a solid solution may be formed. For example, Se dissolves in the position of S in the hydrate, and Se as an elution component is adsorbed and fixed by the coprecipitation phenomenon. In particular, Se is a homologous element of S, and since their ionic radii are about the same, they are easily incorporated into the S position of the hydrate so that they can be fixed very stably. It is difficult to elute. Further, Pb, F, Cd, As, B, and Cr (hexavalent) are fixed in a state of being adsorbed on the surface of the hydrate, and a state that is extremely difficult to elute is realized.

  As described above, in the present invention, at least one of Ca ions, Al ions, and S-containing ions is eluted in the presence of water to a substance from which a trace amount of chemical components such as Pb, F, and Se may be eluted. By mixing and processing a predetermined amount of the processing substance, the hydrate is formed and the elution components that may elute such as Pb, F, Se, Cd, As, B, Cr (hexavalent) Since it is fixed to the hydrate, the elution of these elution components can be reliably prevented or suppressed, and a stabilizing material in which these components are below the reference value can be produced.

By the way, the hydrate to be generated varies depending on the pH when the elution component-containing substance and the treatment substance are blended.
When the pH is less than 4, a hydrate containing Ca, Al, and S is not formed. Accordingly, the pH is preferably 4 or more because it does not have an effect of suppressing the eluted components. When the pH is 4 or more and less than 9, an amorphous hydrate containing Ca, Al, and S is formed, which has an elution suppressing effect of the eluted components. When the pH is 9 or more, a large amount of ettringite and / or kuzerite is formed, and these have a very high elution suppressing effect. Therefore, the pH is preferably 9 or more, more preferably 10 or more.

In addition, in this invention, when the Ca, Al, or S content part is originally contained also in the said elution component containing material, the said processing substance mix | blended with this contains all of Ca, Al, and S. It is not necessary to include only components that are insufficient to form the hydrate among Ca, Al, and S. For example, if elution component-containing material, such as slag can certain amount eluted Al, component missing to form the hydrate Ca, since it is S only, in this case, for example, gypsum (CaSO 4 _· 2H ₂ O) may be blended as the treatment substance. For this reason, in this invention, the processing substance for mix | blending with an elution component containing substance and forming a stabilization material is "the processing substance which elutes at least 1 sort (s) of Ca ion, Al ion, and S containing ion in presence of water. "

  In the present invention, when preparing the stabilizing material by blending the treatment substance with the elution component-containing substance, these are mixed by a heavy machine or a mixer, or the elution component-containing substance is used after being crushed. If this is the case, the processing substance is added at the crushing plant or blended before being inserted into the crushing plant.

  Thus, in the present invention, it is possible to produce a stabilizing material in which components that may be adversely affected by elution such as Pb, F, Se, Cd, As, B, and Cr (hexavalent) are reduced to a reference value or less. it can. Therefore, the stabilizing material of the present invention is suitable as a civil engineering and building material such as a roadbed material and a ground improvement material. The roadbed material is a material used for the part that has the role of distributing the load from the roadbed provided on the roadbed and transmitting it to the roadbed. The ground improvement material is used to improve the soft ground. The material used for

Examples of the present invention will be described below in comparison with comparative examples.
Here, coal ash is used as an elution component-containing material, and various materials are used as treatment materials to elute at least one of Ca ions, Al ions, and S-containing ions in the presence of water, and these are mixed using a mixer. By mixing them, several kinds of stabilizing materials were manufactured. And about the stabilization material manufactured in this way, the elution test which paid its attention especially to Se, and the X-ray diffraction were performed. In the X-ray diffraction, all the manufactured stabilizing materials were measured for those having a particle size of 2 mm or less. Further, the composition of the formed material analyzed to be amorphous by X-ray diffraction was subjected to wet analysis. Furthermore, the average particle size described later is a particle size corresponding to 50% of the distribution curve on the sieve. The environmental standard value of Se is 0.01 mg / L.

(Test No. 1)
First, the said elution test was done about the material (comparative example 1) manufactured without adding the processing substance which elutes Ca ion etc. about coal ash. The results are shown in Table 1. As is apparent from Table 1, the amount of Se eluted was 0.050 mg / L, which was higher than the environmental standard value. Further, as a result of X-ray diffraction of the produced material, ettringite and kuserite were not identified.

(Test Nos. 2 to 8)
Next, as treatment substances for eluting Ca ions, Al ions, and S-containing ions, calcium hydroxide, aluminum sulfate, blast furnace slow-cooled slag, steelmaking slag, each of which has a value as shown in Table 2, The said elution test was done about the material manufactured by adding gypsum in the ratio shown in Table 1. The results are shown in Table 1. These substances were all used having a particle size of 2 mm or less and an average particle size of 0.015 mm. As is apparent from Table 1, test No. which is a conforming example of the present invention. In Examples 1 to 7 of 2 to 8, the elution amount of Se was 0.002 to 0.008 mg / L, both of which were lower than the environmental standard of 0.01 mg / L. As a result of X-ray diffraction of these materials, ettringite and / or kuzerite and amorphous hydrates containing Ca, Al and S were identified.

  From the above results, it was confirmed that the elution of Se can be prevented or suppressed very effectively by the present invention. Similarly, it has been confirmed that the elution of Pb, F, Cd, As, B, and Cr (hexavalent) can be effectively suppressed or prevented.

  In the present invention, Pb, F, Cd, As, B, Cr (hexavalent), and a treatment substance that elutes Ca ions, Al ions, and S-containing ions are mixed with an eluting component-containing substance such as coal ash. The elution of the elution components such as Se is extremely effectively prevented or suppressed, and a stabilization material is obtained in which these are below the standard value. Such a stabilization material is used for civil engineering / ground improvement materials, roadbeds. It can be used as civil engineering and building materials such as road materials such as wood, asphalt, cement materials, and concrete materials, and can also be used as fertilizer materials, and its industrial value is extremely high.

Claims (11)

  A treatment substance that elutes at least one of Ca ions, Al ions, and S-containing ions in the presence of water with respect to an elution component-containing substance containing a predetermined elution component with respect to 100 parts by mass of the elution component-containing substance A method for treating an elution component-containing substance, comprising blending at a ratio of 1 to 100 parts by mass, forming a hydrate containing Ca, Al and S and fixing the predetermined elution component to the hydrate .   The method for treating an elution component-containing substance according to claim 1, wherein the hydrate is ettringite and / or kuserite.   The elution component according to claim 1 or 2, wherein the predetermined elution component is one or more selected from Pb, F, Se, Cd, As, B, and Cr (hexavalent). Treatment method for contained substances.   The said elution component containing material is coal ash, The processing method of the elution component containing material as described in any one of Claims 1-3 characterized by the above-mentioned.   The treatment substance is selected from calcium hydroxide, steel slag, ordinary Portland cement, alumina cement, gypsum, waste concrete, aluminum hydroxide, aluminum sulfate, alumina-containing brick, aluminum ash, alumina-containing waste and sulfur compounds 1 It is a seed | species or more, The processing method of the elution component containing substance as described in any one of Claims 1-4 characterized by the above-mentioned.   By the processing method of the elution component-containing material according to any one of claims 1 to 5, the stabilization material in which the predetermined elution component is fixed to the hydrate and stabilized is manufactured. The manufacturing method of the stabilizing material characterized.   A treatment substance that elutes at least one of Ca ions, Al ions, and S-containing ions in the presence of water with respect to an elution component-containing substance containing a predetermined elution component with respect to 100 parts by mass of the elution component-containing substance It is blended at a ratio of 1 to 100 parts by mass, a hydrate containing Ca, Al and S is formed, and the predetermined elution component is fixed and stabilized in the hydrate. Stabilization material.   The stabilizing material according to claim 7, wherein the hydrate is ettringite and / or kuserite.   The stabilization according to claim 7 or 8, wherein the predetermined elution component is at least one selected from Pb, F, Se, Cd, As, B, and Cr (hexavalent). Materials.   The stabilizing material according to any one of claims 7 to 9, wherein the elution component-containing substance is coal ash.   The treatment substance is selected from calcium hydroxide, steel slag, ordinary Portland cement, alumina cement, gypsum, waste concrete, aluminum hydroxide, aluminum sulfate, alumina-containing brick, aluminum ash, alumina-containing waste and sulfur compounds 1 It is a seed | species or more, The stabilization material as described in any one of Claims 7-10 characterized by the above-mentioned.