JP2016187780A - Toxic material insolubilization agent, and insolubilization method of toxic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toxic material insolubilization agent capable of insolubilizing a toxic material efficiently in a short time, and to provide an insolubilization method of the toxic material.SOLUTION: A toxic material insolubilization agent includes a compound A showing acidic property and containing aluminum, and a compound B containing at least either of magnesium and calcium. In an insolubilization method of a toxic material, the compound A showing acidic property and containing aluminum and the compound B containing at least either of magnesium and calcium are mixed with a toxic material inclusion including the toxic material.SELECTED DRAWING: None

Description

  The present invention relates to a hazardous substance insolubilizing agent and a hazardous substance insolubilizing method.

  Various methods for treating toxic substances such as fluorine and heavy metals contained in slag, factory wastewater, factory wastewater, groundwater from contaminated soil, incineration ash, coal ash, foundry sand, waste gypsum, etc. A method is being considered. Against this background, the Soil Contamination Countermeasures Law was enacted in Japan in 2003, and cadmium and its compounds, lead and its compounds, hexavalent chromium compounds, arsenic and its compounds, mercury and its compounds, as heavy metals, Selenium and its compounds, fluorine and its compounds, boron and its compounds, and cyan compounds are specified as the second class specific harmful substances.

  Among the above, the slag generated in the steel manufacturing process contains fluorine derived from fluorite at a high concentration, and the elution of fluorine may be a problem when the slag is reused. Currently, when reusing slag for roadbed materials, etc., use the Environment Agency Notification No. 46 dissolution test (hereinafter also referred to as “46 dissolution test”) and the dissolution test method prescribed in JIS, It is confirmed whether the amount of elution meets the soil environmental standards. Until now, the elution test of fluorine was performed as it was when it was reused as defined by JIS, but in the future, the elution test at -2.00mm specified in the No. 46 elution test will be imposed, and more severe elution The standard may be revised for testing. For this reason, some slags that have been cleared in the past require insolubilization treatment, and further examination of insolubilizing agents and insolubilizing methods for preventing elution is required.

  Under such circumstances, for example, Patent Document 1 proposes a fluorine insolubilizing agent obtained by dissolving a solid alkali phosphate (earth) metal salt in an acidic solution. In Patent Document 2, a poorly soluble calcium compound (calcium hydroxide, calcium hydrogen phosphate dihydrate, calcium phosphate) is added to and mixed with inorganic waste, and then a fluorine adsorbent (monosulfate, ettringite, A solidifying agent has been proposed in which apatite, magnesia, and magnesium hydroxide) are added and mixed to reduce the fluorine to 0.8 mg / L or less. Further, in Patent Document 3, steel slag (A) having a fluorine content of 0.15 mass% or more has a mineral phase containing phosphorus and calcium and has a fluorine content of less than 0.15 mass% (B ) Is added to form a sparingly soluble compound containing fluorine and fixed to slag.

JP 2009-189927 A JP 2012-214591 A JP 2009-40650 A

  However, since the fluorine insolubilizing agent of Patent Document 1 dissolves a solid alkali phosphate (earth) metal salt and adds it to the slag, facilities and processes for dissolving the metal salt increase. In addition, since processing is performed using only phosphorus, a large amount of phosphorus, which is a valuable resource, is used, resulting in an increase in processing cost.

  In the soil solidifying agent of Patent Document 2, the treatment agent may be added in a large amount of 1 to 250 parts by weight of the poorly soluble calcium compound and 0.1 to 10 parts by weight of the fluorine adsorbent with respect to 100 parts by weight of the waste. Yes, the processing cost is high.

  In the processing method of Patent Document 3, steel slag (B) having a phosphorus content of 0.3 mass% or more (preferably 0.6 mass% or more) and a calcium elution amount of 100 mg / L or more eluted in the No. 46 dissolution test. The process becomes complicated due to restrictions such as the use of.

  The present invention has been made in view of the above, and an object of the present invention is to provide a hazardous substance insolubilizing agent and a hazardous substance insolubilization method capable of insolubilizing a harmful substance efficiently in a short time.

  The present inventors have found that the above problem can be solved by a combination of a compound that shows acidity and contains aluminum and a compound containing at least one of magnesium and calcium, and has completed the present invention.

That is, the present invention is as follows.
[1] A hazardous substance insolubilizing agent comprising a compound A which shows acidity and contains aluminum, and a compound B which contains at least one of magnesium and calcium.
[2] The toxic substance insolubilizer according to [1], wherein the toxic substance insolubilized by the toxic substance insolubilizer is at least one selected from the second type specified toxic substances.
[3] The hazardous substance insolubilizing agent according to [1] or [2], wherein the compound A is at least one of aluminum sulfate, aluminum chloride, and alumina.
[4] The hazardous substance insolubilizing agent according to any one of [1] to [3], wherein the compound B is dolomite or a dolomite compound.
[5] The hazardous substance insolubilizing agent according to any one of [1] to [4], wherein the compounding amount of the compound B with respect to 100 parts by mass of the compound A is 10 to 200 parts by mass.

[6] A method for insolubilizing a harmful substance, comprising mixing compound A, which shows acidity and contains aluminum, and compound B, which contains at least one of magnesium and calcium, into a harmful substance-containing substance containing a harmful substance.
[7] The method for insolubilizing a harmful substance according to [6], wherein the mixing order of the compound A, the compound B, and the harmful substance-containing substance is any one of the following (1) to (3).
(1) The compound A and the compound B are mixed with each other, or the compound A and the compound B are mixed with the harmful substance-containing material simultaneously or sequentially.
(2) After mixing the compound A and the harmful substance-containing material, the compound B is mixed.
(3) After mixing the compound B and the harmful substance-containing material, the compound A is mixed.
[8] The mixing order is the order described in the above (1), and the toxic substance insolubilizing agent according to any one of [1] to [5] is used to mix the above (1) [7] The method for insolubilizing harmful substances described in 1.
[9] The method for insolubilizing a hazardous substance according to [8], wherein in (1), the mixture is granulated by mixing with the harmful substance-containing material.

  According to the present invention, it is possible to provide a hazardous substance insolubilizing agent and a hazardous substance insolubilization method capable of efficiently insolubilizing harmful substances in a short time.

[1] Hazardous substance insolubilizing agent The hazardous substance insolubilizing agent of the present invention (hereinafter sometimes simply referred to as “insolubilizing agent”) is a compound A that shows acidity and contains aluminum, and a compound B that contains at least one of magnesium and calcium. Including.

In Compound A, it is presumed that the aluminum component contained in the crystal is insolubilized (insolubilized) by adsorbing and immobilizing heavy metals and the like that are harmful substances.
In addition, it is assumed that the aluminum component in compound A forms crystals such as ettringite (tricalcium aluminate) together with the calcium component in compound B, and at that time traps harmful substances in the crystal and insolubilizes them. Is done.
In addition, the magnesium component in compound B is partially incorporated into the crystal structure of the produced ettringite, serves to lower the crystallinity of ettringite and increase the initial reactivity, and to produce crystals when producing magnesium hydroxide. It is assumed that toxic substances are trapped in the structure and insolubilized.
As described above, the coexistence of the compound A and the compound B makes it possible to insolubilize harmful substances efficiently in a short time compared to the case where each of them is used alone.

  Examples of the hazardous substance-containing material that is insolubilized by the hazardous substance insolubilizer of the present invention include liquid substances and solid substances. The liquid substances include waste water containing hazardous substances, and the solid substances include slag generated in the steel manufacturing process. , Soil containing harmful substances, incinerated ash, coal ash, foundry sand, waste gypsum, etc. The harmful substance-containing material is preferably a solid material, and more preferably slag.

  Hazardous substances contained in hazardous substances include cadmium, lead, hexavalent chromium, arsenic, mercury, selenium, categorized as Class II Specified Hazardous Substances stipulated by the Soil Contamination Countermeasures Law enacted in 2003. Fluorine, boron, cyan, antimony and the like can be exemplified, and these compounds are also included. Among these, cadmium, selenium, arsenic, fluorine, boron, and antimony are preferable from the viewpoint that the harmful substance insolubilizing agent of the present invention exhibits a high insolubilizing effect, and more preferable are fluorine, boron, and antimony. . In the present invention, wastewater containing toxic substances, soil, incineration ash, coal ash, slag, foundry sand, and waste gypsum may contain one or more of the toxic substances exemplified above, but may contain two or more. You may go out.

Compound A shows acidity, but this “acidity” means that 1 g of a compound containing aluminum is dissolved or dispersed in 100 ml of pure water, and the pH is 6.0 or less in the state of a solution or dispersion. . It can react efficiently with the compound B which shows alkalinity because pH is 6.0 or less.
Examples of such compound A include aluminum sulfate, aluminum chloride, alumina, and the like. Among these, aluminum sulfate is preferable.
Compound A may be a single compound or a mixture of multiple compounds.

  The compound B containing at least one of magnesium and calcium is at least one of “a compound containing calcium” and “a compound containing magnesium and calcium” from the viewpoint of promoting insolubilization of harmful substances accompanying the formation of ettringite by the calcium component. From the viewpoint of further promoting the insolubilization of harmful substances by the combined effect of coexistence of the magnesium component with the calcium component, “a compound containing magnesium and calcium” is more preferable.

  Among the compounds B, examples of the compound containing magnesium include magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium chloride, magnesium sulfate, and the like, among which magnesium oxide is preferable.

  Among the compounds B, examples of the compound containing calcium include calcium carbonate, calcium oxide, calcium hydroxide, calcium chloride and the like, and among them, calcium carbonate and calcium oxide are preferable.

  Furthermore, examples of the compound containing magnesium and calcium include dolomite and dolomite compounds derived from dolomite. Examples of the dolomite compound include semi-baked dolomite, light-burned dolomite, and hydrated dolomite.

Here, Dolomite is ideally a double salt of calcium carbonate (CaCO ₃ ) called calcite and magnesium carbonate (MgCO ₃ ) called magnesite. It is. In terms of components, this is a substance located between calcite and magnesite. When dolomite is heated under relatively mild conditions, a decarboxylation reaction occurs and a mixture of calcium oxide (CaO) and magnesium oxide (MgO) called “light burned dolomite” is obtained. If lightly burned dolomite is digested by adding water, dolomite hydroxide, which is a mixture of calcium hydroxide (Ca (OH) ₂ ) and magnesium hydroxide (Mg (OH) ₂ ), is obtained.

  Moreover, a semi-baked dolomite refers to the dolomite semi-baked product which has a magnesium oxide and a calcium carbonate as a main component. Semi-baked dolomite decalcifies most of the magnesium carbonate in the dolomite component by calcining dolomite at a temperature of 600 to 900 ° C. to make magnesium oxide, while calcium carbonate hardly decarboxylates, It can be obtained by leaving it as it is.

The content of free magnesium oxide in the semi-baked dolomite is preferably 8% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more.
Here, the content of free magnesium oxide refers to an amount calculated as the amount (mass%) of magnesium oxide (MgO) produced by decarboxylation of magnesium carbonate (MgCO ₃ ) in dolomite. The calculation can be performed according to the following procedure.

  First, CaO, MgO and Ig.loss (loss on ignition) are analyzed by a method defined in “Analyzing Method of Lime” of JIS R9011. Next, either (i) or (ii) below is selected depending on whether or not the amount of free calcium oxide obtained by analysis has reached 1.5% by mass.

(I) When the amount of free calcium oxide is 1.5% by mass or more: The value of MgO obtained by analysis is adopted as the amount of free magnesium oxide as it is.
(Ii) When the amount of free calcium oxide is less than 1.5% by mass: The amount of free magnesium oxide is calculated by [MgO present as MgO—MgCO ₃ obtained by analysis].
The amount of MgO present as MgCO ₃ is determined by the following formula.
MgO present as MgCO ₃ (mass%) = {Ig.loss− (CaO ÷ 56 × 44)} ÷ 44 × 40

  As the light-burned dolomite and the hydroxylated dolomite, the special stipulated in JIS R9001 and No. 1 light-burned dolomite and hydroxylated dolomite are suitable. The process of preparing hydroxylated dolomite, because lightly burned dolomite reacts with water contained in wastewater, soil, incineration ash, coal ash, etc., which are toxic substances, and is hydrated by digestion and converted to hydroxylated dolomite Even if light-burned dolomite is used as it is, the effect of hydroxylated dolomite is exhibited.

In the dolomite and dolomite compounds, since the magnesium component and the calcium component coexist in the compound at the crystal particle level, the cooperative effect of the three components of the aluminum component of the compound A, the magnesium component and the calcium component is exhibited. It is assumed that it is easy to insolubilize harmful substances in a shorter time.
Therefore, as the compound B, dolomite and dolomite compounds are preferable, and semi-baked dolomite is more preferable.

  Compound B may be a single compound or a mixture of multiple compounds. The dolomite and the dolomite compound may contain other components such as calcium carbonate, calcium oxide, magnesium carbonate, silicon dioxide, aluminum oxide, and ferric oxide as long as the effects of the present invention are not hindered. .

The compounding amount of Compound B with respect to 100 parts by mass of Compound A is preferably 10 to 200 parts by mass, and more preferably 10 to 150 parts by mass. By being 10-200 mass parts, it can adjust to the optimal conditions according to the composition of a process target.
That is, for example, in the case of a harmful substance-containing material (free-CaO: 5 to 20% by mass) having a large amount of free lime (free-CaO) as described later, the compounding amount of Compound B with respect to 100 parts by mass of Compound A is 10 It is preferable in order of -70 mass parts, 10-30 mass parts, and 10-15 mass parts.
Further, in the case of a harmful substance-containing material (free-CaO: 0.1 to 5% by mass) with a large amount of free lime (free-CaO), the compounding amount of compound B with respect to 100 parts by mass of compound A is 60 to 150 masses. Parts, 60 to 110 parts by mass, and 60 to 80 parts by mass in this order.

  The insolubilizing agent of the present invention may contain other components as long as the effects of the present invention are not hindered. Examples of other components include water for slurrying.

[2] Method for Insolubilizing Hazardous Substances The method for insolubilizing hazardous substances according to the present invention comprises a compound A that shows acidity and contains aluminum, and a compound B that contains at least one of magnesium and calcium. Mix in the product. Here, details of Compound A and Compound B are as described above.

  Known methods such as a method of charging and mixing the harmful substance insolubilizing agent of the present invention in a powder form, a method of mixing in a slurry form by mixing with water, and the like are applied to substances containing harmful substances. In this way, the harmful substances can be sufficiently insolubilized. In the case of charging with powder, a mixture of compound A and compound B in advance may be added, or compound A and compound B may be added separately at the same time, or may be sequentially added separately. . When the slurry is charged, the mass ratio of the insolubilizer to water [insolubilizer / water] is preferably 0.03 to 0.2.

  As described above, the mixing order of the compound A, the compound B, and the harmful substance-containing material is not particularly limited. For example, a part of compound A and / or compound B is mixed with a harmful substance-containing material, and a part or the remaining compound B and / or compound A is further mixed with a harmful substance-containing material, It can be set according to the hazardous substance content and the surrounding environment, such as batch mixing for batch mixing. Among these, any of the following (1) to (3) is preferable.

(1) The compound A and the compound B are mixed, or the compound A and the compound B are mixed with the harmful substance-containing material simultaneously or sequentially.
(2) Compound B is mixed with Compound A and a hazardous substance-containing material.
(3) Compound A is mixed with Compound B and a hazardous substance-containing material.

As the mixing order, the order described in (1) is preferable, and it is more preferable to perform the mixing in (1) using the above-described harmful substance insolubilizing agent of the present invention.
The hazardous substance insolubilizing agent of the present invention is mainly composed of compound A and compound B. However, if they coexist at the time of mixing with the hazardous substance-containing material, the harmful substance insolubilizing agent of the present invention is used. It falls under the use of.

  When compound A, compound B, and a hazardous substance-containing material are mixed, it is preferable to add water and granulate. By such treatment, the treatment object can be made into a high-strength granulated product. The amount of water during addition is preferably 10 to 50 parts by mass with respect to 100 parts by mass of the mixture (compound A + compound B + hazardous substance-containing or insolubilizing agent + hazardous substance-containing). More preferably, it is part by mass. Moreover, when granulating, a well-known granulator can be used, and the particle diameter after granulation is preferably about 40 mm or less, and more preferably about 20 mm or less. The particle size can be measured with a JIS standard sieve.

  Hereinafter, although the processing method according to the kind of hazardous | toxic substance containing material is illustrated, this invention is not limited to these.

(Slag treatment method)
The method for insolubilizing slag in the present invention is preferably a method for insolubilizing harmful substances in slag by mixing the insolubilizing agent with slag.
The amount of the harmful substance insolubilizing agent added to the slag is preferably 10 to 100 kg / t-slag. When the added amount of the insolubilizing agent is 10 kg / t-slag or more, the slag and the insolubilizing agent are sufficiently mixed, and the effect of suppressing the elution of harmful substances in the slag is sufficiently obtained. When the addition amount of the insolubilizing agent is 100 kg / kg or less, an effect of suppressing the elution of harmful substances according to the addition amount of the insolubilizing agent can be obtained, and an increase in the processing cost after the treatment can be suppressed. From this viewpoint, the amount of the insolubilizing agent added is more preferably 15 to 90 kg / t-slag, and further preferably 30 to 75 kg / t-slag.

Here, examples of slag include steel slag generated as a by-product in the steel manufacturing process. Depending on the type of furnace and the cooling method, blast furnace slag (blast furnace slag, blast furnace granulated slag), steelmaking slag (converter) There are different properties such as slag and electric furnace slag. Steel slag is mainly composed of lime (CaO) and silica (SiO ₂ ). As other components, blast furnace slag contains alumina (Al ₂ O ₃ ), magnesium oxide (MgO) and a small amount of sulfur (S). In the case of steelmaking slag, it contains iron oxide (FeO) and magnesium oxide (MgO). In the case of steelmaking slag, metal elements (such as iron) are incorporated into the slag in the form of oxides, but the refining time is short and the lime content is high. Some remain as free lime (free-CaO). The present invention can be applied to any slag.

  Among the slags as described above, in particular, when there is a large amount of free-CaO in the slag, the pH of the slag becomes high and harmful components are likely to be eluted. Even in such a case, according to the insolubilizing agent of the present invention, a hazardous substance can be insolubilized efficiently in a short time. The free-CaO in the slag in the above case is preferably 0.1 to 20% by mass, and more preferably 0.1 to 5% by mass.

In addition, free-CaO in slag can be calculated | required as follows. First, slag is pulverized to 200 mesh or less, ethylene glycol is added to the pulverized product, and extraction is performed at about 80 ° C. to obtain an extract. Thereafter, the extract is analyzed by ICP, and free-CaO can be obtained by subtracting ₂ minutes of Ca (OH) from the analysis value.

  Moreover, it is preferable that pH after mixing an insolubilizing agent and slag is 7-11.5.

(Wastewater treatment method)
As the insolubilizing method for the hazardous substance-containing wastewater in the present invention, a method in which the insolubilizing agent of the present invention is introduced into the hazardous substance-containing wastewater and mixed and stirred is preferable. Furthermore, from the viewpoint of more effectively reducing the concentration of harmful substances in the wastewater, a multi-stage treatment method, for example, a harmful substance insolubilizing agent is introduced into the wastewater containing harmful substances, and the precipitate is removed by filtration separation. Thereafter, a method of insolubilizing the harmful substance by adding a hazardous substance insolubilizing agent to the filtrate and reacting it again is preferable.

  The amount of the hazardous substance insolubilizer added to the wastewater needs to be determined with respect to the concentration of the harmful substance in the wastewater. For example, if the harmful substance is fluorine, it is necessary to determine the optimum addition amount so that the fluorine concentration in the wastewater after treatment is 8 mg / L or less which is the wastewater standard value. For high-concentration wastewater with a fluorine concentration of several thousand mg / L in the wastewater, the amount of use can be reduced by treating it in a multistage manner.

  From the above viewpoint, the amount of the harmful substance insolubilizer added at a time is preferably 0.05 to 5% by mass with respect to the harmful substance-containing wastewater. When the added amount of the harmful substance insolubilizing agent is 0.05% by mass or more, the effect of suppressing the elution of harmful substances in the waste water can be sufficiently obtained. When the addition amount of the hazardous substance insolubilizing agent is 5% by mass or less, an effect of suppressing the elution of the harmful substance according to the addition amount of the insolubilizing agent can be obtained, and an increase in load and processing cost during stirring can be suppressed. From this point of view, the addition amount of the hazardous substance insolubilizer is more preferably 0.1 to 1.5% by mass and 0.1 to 1.0% by mass with respect to the hazardous substance-containing wastewater. More preferably, it is especially preferable that it is 0.4-0.8 mass%.

The treatment time is usually 10 minutes to 24 hours, preferably 30 minutes to 2 hours.
The treatment wastewater pH after the addition of the hazardous substance insolubilizer is preferably 7 to 13 in order to bring out sufficient treatment performance, and the pH is 10 to 12 when lead, zinc or the like is included as a coexisting substance. It is more preferable.

(Soil treatment method)
The method for insolubilizing the soil containing harmful substances in the present invention is preferably a method for insolubilizing harmful substances in the soil by mixing the insolubilizing agent with the soil.
The amount of the harmful substance insolubilizing agent added to the soil is preferably 50 to 300 kg / m ³ . When the added amount of the insolubilizing agent is 50 kg / m ³ or more, the soil and the insolubilizing agent are sufficiently mixed at the time of construction, and the effect of suppressing the elution of harmful substances in the soil is sufficiently obtained. When the addition amount of the insolubilizing agent is 300 kg / m ³ or less, an effect of suppressing the elution of harmful substances according to the addition amount of the insolubilizing agent is obtained, and the increase in the soil volume after the treatment and the increase in the treatment cost can be suppressed. it can. In this respect, the amount of insolubilizing agent is more preferably 50~150kg / ^{m 3,} even more preferably from 50 to 100 / ^{m 3.}
The treated soil after the addition of the insolubilizer is preferably pH 6-8, more preferably pH 7-8, from the viewpoint of groundwater contamination and human exposure.

(Incineration ash treatment method / coal ash treatment method)
As a method for insolubilizing harmful substances contained in incineration ash or coal ash in the present invention, there is a method for insolubilizing harmful substances contained in incineration ash or coal ash by mixing the insolubilizing agent with incineration ash or coal ash. preferable.
The amount of the harmful substance insolubilizing agent added to the incineration ash or coal ash is preferably 1 to 50% by mass with respect to the incineration ash or coal ash. When the addition amount of the insolubilizing agent is 1% by mass or more, the incineration ash and the insolubilizing agent are sufficiently mixed at the time of construction, and the effect of suppressing the elution of harmful substances in the incineration ash or coal ash is sufficiently obtained. When the added amount of the insolubilizing agent is 50% by mass or less, an effect of suppressing the elution of harmful substances according to the added amount of the insolubilizing agent is obtained, and the volume of the incinerated ash or coal ash after processing is increased and the processing cost is increased. Can be suppressed. From this viewpoint, the addition amount of the insolubilizing agent is more preferably 3 to 30% by mass, and further preferably 5 to 20% by mass with respect to the incinerated ash or coal ash.

  Incineration ash or coal ash includes, for example, paper sludge incineration ash from paper mills, biomass-based incineration ash generated when wood biomass fuel is burned in a boiler, incineration ash generated in municipal waste incinerators (dust, fly ash, and so on). Main ash), coal ash generated during coal-fired power generation, sewage sludge incineration ash, combustion ash of various industrial wastes, etc., but limited to these if incineration ash or coal ash containing hazardous substances Not.

After obtaining a mixture in which the insolubilizing agent and incineration ash or coal ash are mixed, water can be added to cure the mixture from the viewpoint of enhancing the elution suppression effect of harmful substances. There is no particular limitation on the curing method, and the mixture of the insolubilizing agent and the incinerated ash or coal ash may be left alone, or the mixture may be mixed while gently mixing. The curing period is preferably 1 to 30 days, and more preferably 3 to 10 days. If it is 1 day or more, sufficient elution suppression effect and strength development effect of harmful components are obtained, and if it is within 30 days, the elution suppression effect of harmful components is improved.
By treating the incineration ash or coal ash with the hazardous substance insolubilization method of the present invention, the incineration ash or coal ash satisfying the environmental standard value according to the Environment Agency Notification No. 46 can be effectively used for roadbed materials and the like. .

(Treatment methods for other hazardous substances)
With respect to other hazardous substance-containing materials, the hazardous substances can be insolubilized with reference to the above-mentioned “processing method of hazardous substance-containing materials” with reference to known processing methods as necessary.
Examples of other hazardous substance-containing materials include, but are not limited to, foundry sand and waste gypsum.

  As described above, the method for insolubilizing harmful substances according to the present invention is efficient in terms of both time and work because it only requires mixing the insolubilizing agent with the solid containing harmful substances.

  EXAMPLES Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

(Examples 1 to 3 and Comparative Examples 1 and 2)
Aluminum sulfate, semi-baked dolomite, and hydroxyapatite were blended as shown in Table 1 below to prepare hazardous substance insolubilizers of Examples 1 to 3 and Comparative Examples 1 and 2.
In addition, aluminum sulfate, semi-baked dolomite, and hydroxyapatite used the following.
Aluminum sulfate: Aluminum sulfate manufactured by Daimei Chemicals Co., Ltd. Semi-baked dolomite: Metal clear 1000 manufactured by Yoshizawa Lime Industry Co., Ltd.
・ Hydroxyapatite: Reagent hydroxyapatite manufactured by Wako Pure Chemical Industries, Ltd.

The mixing ratio of the insolubilizing agent in each case with steel slag A pulverized to 2.00 mm or less is mixed in the bag as shown in Table 1 to insolubilize steel slag (slag A). A fluorine dissolution test based on Notification No. 46 was conducted. Slag A is a thing containing 5-20 mass% (in the form of CaO or Ca (OH) ₂ ) free-CaO. The results are shown in Table 1 below.
In addition, the comparative example 1 is an example which has not performed the insolubilization process. The pH of the dissolution test was analyzed with a HORIBA pH meter, and the F concentration was determined by an absorptiometric method according to JISK0102.

As shown in Comparative Example 2, although the hydroxyapatite showed an insolubilizing effect, the fluorine concentration did not satisfy the standard value (0.8 mg / L or less). As shown in Example 1, by adding 5 parts by mass of an insolubilizer containing 90% by mass of aluminum sulfate and 10% by mass of semi-baked dolomite to 100 parts by mass of slag, the fluorine elution amount became below the reference value.
In Examples 2 and 3, since the content of free-CaO was high, the fluorine concentration did not satisfy the standard value (0.8 mg / L or less), but for this, the amount of addition of the insolubilizing agent was increased. It can be below the reference value.

(Examples 4-6 and Comparative Examples 3-5)
Aluminum sulfate and semi-baked dolomite were blended as shown in Table 2 below to prepare hazardous substance insolubilizers of Examples 4 to 6 and Comparative Examples 3 to 5.
In addition, what was used in "Examples 1-3 and Comparative Examples 1 and 2" was used for aluminum sulfate and semi-baked dolomite.

As shown in Table 2, the mixing ratio of the insolubilizing agent in each case with electric furnace slag (slag B) crushed to 2.00 mm or less is mixed in the bag, and slag B is insolubilized. A fluorine elution test based on No. 46 was conducted. The slag B contains 0.1 to 5% by mass of free-CaO (in the form of CaO or Ca (OH) ₂ ). The results are shown in Table 2 below.
In addition, the comparative example 3 is an example which has not performed the insolubilization process. The dissolution test was the same as in Examples 1 to 3 and Comparative Examples 1 and 2.

Even in the case of only the semi-baked dolomite of Comparative Example 4, a certain elution preventing effect was obtained, but as shown in Examples 4 to 6, a higher effect was exhibited in combination with aluminum sulfate. It seems that the insolubilization effect by MgO in semi-baked dolomite and the insolubilization effect by ettringite were obtained synergistically. As shown in Comparative Example 5, when only aluminum sulfate was used, the pH was lowered, the elution preventing effect was insufficient, and the environmental standard value could not be satisfied.

Claims (9)

Compound A showing acidity and containing aluminum;
A hazardous substance insolubilizing agent comprising: Compound B containing at least one of magnesium and calcium.   The hazardous substance insolubilizing agent according to claim 1, wherein the hazardous substance insolubilized by the hazardous substance insolubilizing agent is at least one selected from the second type specific harmful substances.   The hazardous substance insolubilizing agent according to claim 1 or 2, wherein the compound A is at least one of aluminum sulfate, aluminum chloride, and alumina.   The hazardous substance insolubilizing agent according to any one of claims 1 to 3, wherein the compound B is dolomite or a dolomite compound.   The compounding quantity of the said compound B with respect to 100 mass parts of compounds A is 10-200 mass parts, The harmful substance insolubilizer of any one of Claims 1-4.   A method for insolubilizing a harmful substance, comprising mixing compound A, which shows acidity and contains aluminum, and compound B, which contains at least one of magnesium and calcium, into a harmful substance-containing substance containing a harmful substance. The method for insolubilizing a harmful substance according to claim 6, wherein the mixing order of the compound A, the compound B, and the harmful substance-containing material is any one of the following (1) to (3).
(1) The compound A and the compound B are mixed with each other, or the compound A and the compound B are mixed with the harmful substance-containing material simultaneously or sequentially.
(2) After mixing the compound A and the harmful substance-containing material, the compound B is mixed.
(3) After mixing the compound B and the harmful substance-containing material, the compound A is mixed.   The said mixing order is the order as described in said (1), The mixing of said (1) is performed using the hazardous | toxic substance insolubilizing agent of any one of Claims 1-5. Methods for insolubilizing hazardous substances. The method for insolubilizing a harmful substance according to claim 8, wherein in (1), the mixture is granulated by adding water during mixing with the harmful substance-containing material.