JP2014094877A - Earthwork material composition and method of reducing fluorine elution amount in the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a burned product capable of being used as a suitable material such as an aggregate, a roadbed material, a banking material and a backfill material for mortar or concrete, while capable of efficiently using waste and the like as a raw material.SOLUTION: An earthwork material composition contains a magnesium-containing insolubilization material, which is obtained by hydration of a burned product A containing 2CaO AlOSiOof 10 to 100 pts.mass based on 100 pts.mass of a component (A) 2CaO SiOand having the content of 3CaO AlOof 20 pts.mass or less, and containing barium of 0.02 to 0.2 mass% and zinc of 0.03 to 0.5 mass% in 100 mass% of the burned product, and a burned product B containing magnesium oxide and magnesium carbonate obtained by burning a mineral containing a component (B) magnesium carbonate as a main ingredient at 650 to 1,000°C so that a part of the burned product B becomes magnesium hydroxide, and contains a powder comprising a magnesium-based material having ignition loss rate of 6 to 30 mass% at 1,000°C.

Description

  The present invention relates to an earthwork material composition suitable as a civil engineering / portal material such as aggregate, roadbed material, embankment material and backfill material for mortar and concrete, and a method for reducing the amount of fluorine elution in the earthwork material composition.

In recent years, with the economic growth and population concentration in urban areas, industrial waste, general waste, etc. are rapidly increasing. Conventionally, most of these wastes have been disposed of in landfills after being reduced in volume by incineration. However, under the current situation where the remaining capacity at landfill sites is becoming tight, new waste disposal methods have been established. There is an urgent need. In order to respond to such an urgent need, for example, Patent Document 1 proposes a fired product that can effectively use waste as a raw material.
The fired product can be used as a cement additive by being pulverized, and can be used as a material for mortar, concrete aggregate, roadbed material, embankment material, backfill material, etc. without pulverization. You can also.

  On the other hand, Patent Document 2 proposes an insolubilizing material capable of suppressing elution of heavy metals and the like with respect to soil contaminated with heavy metals such as lead, hexavalent chromium and arsenic and fluorine. By using wood, it is possible to prevent the spread of pollution to the surrounding environment such as groundwater and the loss of effective use of land due to an increase in soil contamination concentration.

JP 2004-2155 A JP 2010-131517 A

  However, in recent years, the amount of cement production in Japan has been declining. Therefore, it is difficult to consume a large amount of rapidly increasing waste and the like only by using the fired product described in Patent Document 1 as a cement additive. . Moreover, even if such fired products are used for aggregates, roadbed materials, etc., there is still room for improvement in order to provide sufficient weight and crushing resistance to achieve high crushing strength suitable for use in these. is there.

  The insolubilizing material described in Patent Document 2 is intended to reduce the concentration of heavy metals, etc. exclusively by adding it to contaminated soil, and is used for aggregates, roadbed materials, embankment materials and embedding materials for mortar and concrete. No specific study has been made on obtaining a high-performance composition as an earthwork material such as a return material.

  Therefore, the object of the present invention is to be able to use wastes and the like effectively as raw materials, and to be used as suitable materials such as aggregates, roadbed materials, embankment materials and backfill materials for mortar and concrete. It is in providing the baked product which can be performed.

  Therefore, the present inventor has made various studies, and by using a calcined product having a specific mineral composition and containing a specific amount of barium and zinc, and a magnesium-containing insolubilized material containing a specific powder, the fluorine elution amount can be reduced. It has been found that an earthwork material composition that can be effectively reduced to increase safety and sufficiently increase strength can be obtained, and the present invention has been completed.

That is, the present invention includes the following components (A) and (B):
(A) relative to 2CaO · SiO ₂ 100 parts by mass, the _{2CaO · Al 2 O 3 · SiO} 2 containing 10 to 100 parts by weight, and firing the content of 3CaO · Al ₂ O ₃ is not more than 20 parts by weight A calcined product A containing 0.02 to 0.2% by mass of barium and 0.03 to 0.5% by mass of zinc in 100% by mass of the calcined product, and (B) carbonic acid A fired product B containing magnesium oxide and magnesium carbonate obtained by firing a magnesium-based mineral at 650 to 1,000 ° C. was hydrated so that a part of the fired product B was magnesium hydroxide. In addition, the present invention provides an earthwork material composition including a magnesium-containing insolubilized material containing a powder made of a magnesium-based material having a loss on ignition at 1,000 ° C. of 6 to 30% by mass.

The present invention also includes the following components (A) and (B):
(A) relative to 2CaO · SiO ₂ 100 parts by mass, the _{2CaO · Al 2 O 3 · SiO} 2 containing 10 to 100 parts by weight, and firing the content of 3CaO · Al ₂ O ₃ is not more than 20 parts by weight A calcined product A containing 0.02 to 0.2% by mass of barium and 0.03 to 0.5% by mass of zinc in 100% by mass of the calcined product, and (B) carbonic acid A fired product B containing magnesium oxide and magnesium carbonate obtained by firing a magnesium-based mineral at 650 to 1,000 ° C. was hydrated so that a part of the fired product B was magnesium hydroxide. Fluorine elution amount in an earthwork material composition comprising a step of mixing a magnesium-containing insolubilized material containing a powder made of a magnesium-based material having a loss on ignition at 1,000 ° C. of 6 to 30% by mass The low It provides a way to reduce.

According to the earthwork material composition of the present invention, a specific insolubilizing material and a fired product that can increase the weight and can improve the crushing resistance even if waste or the like is used as a raw material are used in combination. Therefore, the amount of fluorine elution can be effectively reduced, and an earthwork material composition that exhibits high crushing strength while having high safety can be obtained. If it is such a composition, earthwork materials such as aggregates for mortar and concrete, roadbed materials, embankment materials, backfill materials, embankment drain materials, backfill materials, laying materials, covering materials, fillers and roadbed materials It is a very useful composition even when it consumes a large amount of wastes and the like that rapidly increase.
In addition, according to the method for reducing the amount of elution of fluorine in the earthwork material composition of the present invention, the fluorine content in the composition is controlled within a suitable range to provide excellent crushing strength and ensure high safety. Is possible.

In this invention, it is a figure which shows the shape and dimension of a measurement container and funnel used when measuring a capacity | capacitance. In this invention, when measuring volume, it is a figure which shows the state with which the baked material was filled on the funnel inserted in the measurement container.

Hereinafter, the present invention will be described in detail.
The earthwork material composition of the present invention has the following components (A) and (B):
(A) The calcined product of the present invention is a calcined product containing 10 to 100 parts by mass of C ₂ AS with respect to 100 parts by mass of C ₂ S, and the content of C ₃ A is 20 parts by mass or less. The calcined product A contains 0.02 to 0.2% by mass of barium and 0.03 to 0.5% by mass of zinc in 100% by mass of the calcined product, and (B) magnesium carbonate as a main component. A fired product B containing magnesium oxide and magnesium carbonate obtained by firing the mineral to be 650 to 1,000 ° C., so that a part of the fired product B becomes magnesium hydroxide, And the magnesium containing insolubilization material containing the powder which consists of a magnesium-type material whose ignition loss rate in 1,000 degreeC is 6-30 mass% is included.
The fired product of component (A) is referred to as “fired product A”, and the fired product used when obtaining the powder contained in component (B) is referred to as “fired product B”.

The fired product A of the component (A) used in the present invention contains 10 to 100 parts by mass of C ₂ AS with respect to 100 parts by mass of C ₂ S, and the content of C ₃ A is 20 parts by mass or less. It is a fired product, and 0.02 to 0.2% by weight of barium and 0.03 to 0.5% by weight of zinc are contained in 100% by weight of the fired product.

The C ₂ S has hydraulic properties, and can react with relaxation in concrete, roadbed, etc., and can increase the strength by densifying the concrete, roadbed, etc. In addition, although the C ₂ AS does not have hydraulic properties, the C ₂ AS is densified by carbonation, and thus can exert an effect of suppressing the neutralization of concrete or increasing the strength of a roadbed or the like.

The content of C ₂ AS in the fired product A of component (A), with respect to C ₂ S100 parts by mass comprising 10 to 100 parts, preferably 20 to 90 parts by weight, more preferably 25 ~ 80 parts by mass. When the content of C ₂ AS is less than 10 parts by mass relative to 100 parts by mass of C ₂ S, the water absorption rate of the calcined product A may increase and the calcined product may be powdered during cooling ( Dusting) may occur. Moreover, since there exists a possibility that a melt may increase at high temperature when it exceeds 100 mass parts, it exists in the tendency for the breadth of the temperature which can be baked to narrow.

The C ₃ A reduces the water absorption rate of the fired product A, and prevents the occurrence of expansion failure when used as an aggregate or a roadbed material, thereby lowering the durability of concrete or roadbed. From the viewpoint of suppressing this, the content is preferably reduced. Specifically, the content of C ₃ A in the fired product A of component (A) is 20 parts by mass or less, preferably 0 to 10 parts per 100 parts by mass of C ₂ S. Part by mass.

  The fired product A of component (A) contains barium. Thereby, the crushing resistance can be sufficiently increased, and the crushing strength can be increased. The content of barium in the fired product A is 0.02 to 0.2% by weight in 100% by weight of the fired product A, preferably 0.025 to 0.18% by weight, and more preferably 0. 0.03 to 0.15% by mass. If the barium content in 100% by mass of the fired product A is less than 0.02% by mass, the crushing resistance may decrease. In addition, from the viewpoint of economics such as manufacturing costs, the barium content in 100% by mass of the fired product A is preferably 0.2% by mass or less.

  The fired product A of component (A) contains zinc. Thereby, in combination with the barium, more excellent crushing resistance can be realized. The content of zinc in the fired product A is 0.03 to 0.5% by weight, preferably 0.04 to 100% by weight in 100% by weight of the fired product A, from the viewpoint of realizing better crush resistance. It is 0.4 mass%, More preferably, it is 0.05-0.2 mass%. When the zinc content in 100% by mass of the fired product A is less than 0.03% by mass, the crushing resistance may be reduced. In addition, if the zinc content in 100% by mass of the fired product A exceeds 0.5% by mass, zinc may be eluted from the fired product A into the water when concrete is produced, which may cause the setting to be delayed. There is.

The content of SO ₃ in the fired product A of the component (A) is stable in view of facilitating the firing treatment, maintaining high crushing strength and wear resistance in the fired product A, and reducing the water absorption rate. From the viewpoint of increasing, it is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, in 100% by mass of the fired product A.

As a raw material for producing the fired product A having such a composition, a general Portland cement clinker raw material, that is, a CaO raw material such as limestone, quicklime, and slaked lime, a SiO ₂ raw material such as silica and clay, and an Al ₂ such as clay Fe ₂ O ₃ raw materials such as O ₃ raw materials, iron cake, and iron cake can be used.
In addition, as the barium raw material, natural raw materials such as barite and poison barite, and wastes such as waste oil, capacitors, automobile parts, cathode ray tubes, heat treatment agents, pigments and paints can be used.
In addition to industrial zinc oxide, waste tires, waste oil, metal slag, etc. can be used as the zinc raw material.
Furthermore, waste raw materials such as waste gypsum board and waste sulfuric acid can be used as the SO ₃ raw material. Gypsum can also be used. Furthermore, a high sulfur content fuel such as pet coke can also be used.

Furthermore, the content of P ₂ O ₅ in the fired product A of component (A) is preferably 0.3% by mass or more, more preferably 0.4% by mass or more, from the viewpoint of preventing dusting. More preferably, it is 0.5% by mass or more. When the P ₂ O ₅ content in 100% by mass of the fired product A is less than 0.3% by mass, dusting may occur and the powdery material may increase. In addition, the content of P ₂ O ₅ in 100% by mass of the fired product A is preferably 20% by mass or less, more preferably 15% by mass or less, and further preferably 10% from the viewpoint of the cost of the earthwork material. It is below mass%.
The content of P ₂ O ₅ in the fired product A can be adjusted by using phosphorus-containing waste such as sewage sludge as a raw material, or using industrial materials such as calcium hydrogen phosphate. it can.

As described above, dusting may occur when the content of P ₂ O ₅ in the fired product A is less than 0.3% by mass. To effectively prevent this, It is preferable to adjust the total content of K ₂ O and / or Na ₂ O in the fired product. That is, when the content of P ₂ O ₅ in the fired product A of the component (A) is less than 0.3% by mass, K ₂ O and / or Na is used from the viewpoint of preventing dusting and improving easiness of firing. The total content of ₂ O is preferably 1.0 to 5.0 mass%, more preferably 1.5 to 4.5 mass%, still more preferably 2.0 to 4.0 mass%. is there.
The total content of K ₂ O and / or Na ₂ O in the fired product A is adjusted by using waste materials such as waste glass as raw materials or using industrial materials such as sodium carbonate. be able to.

  In the present invention, as the raw material of the fired product A of component (A), one or more selected from industrial waste, general waste, pollutants and construction generated soil can be used. Is preferable from the viewpoint of natural resources and environmental protection. Here, industrial waste includes, for example, coal ash; raw consludge; various sludges such as sewage sludge, purified water sludge, construction sludge, and iron sludge; Secondary ash, construction waste, concrete waste, etc. are listed. Examples of the general waste include sewage sludge dry powder, municipal waste incineration ash, and shells. Examples of contaminants include heavy metal-contaminated soil, organic matter-contaminated soil, barium and zinc-contaminated soil. Examples of construction generated soil include soil and residual soil generated from construction sites and construction sites, and waste soil.

Depending on the raw material composition of the fired product A, in particular, when one or more selected from the above industrial waste, general waste, contaminants and construction generated soil (hereinafter referred to as waste raw material) is used as a raw material, 4CaO.Al ₂ O ₃ .Fe ₂ O ₃ (hereinafter referred to as C ₄ AF) may be produced. In the fired product A of component (A), preferably a part of C ₂ AS, more preferably In C ₂ AS, 70% by mass or less in C ₂ AS may be substituted with C ₄ AF. When C ₄ AF is substituted beyond this range, the firing temperature range becomes narrow, and the production control may become difficult.

The mineral composition (C ₄ AF, C ₃ A, C ₂ AS, C ₂ S) of the fired product A of component (A) is the raw material used and the CaO, SiO ₂ , Al ₂ O ₃ , Fe _{2 in the} fired product A. each content of O ₃ from (wt%) can be determined by the following equation.
C ₄ AF = 3.04 × Fe ₂ O ₃
C ₃ A = 1.61 × CaO−3.00 × SiO ₂ −2.26 × Fe ₂ O ₃
C ₂ AS = −1.63 × CaO + 3.04 × SiO ₂ + 2.69 × Al ₂ O ₃ + 0.57 × Fe ₂ O ₃
C ₂ S = 1.02 × CaO + 0.95 × SiO ₂ -1.69 × Al ₂ O ₃ −0.36 × Fe ₂ O ₃

The content of the burned material of barium in A, zinc and SO ₃ component (A) is a value calculated from the composition of the obtained baked product A. Therefore, for example, when barium or zinc is insufficient in the raw material used, the barium raw material or zinc raw material may be mixed and used in order to adjust the shortage. What is necessary is just to determine a mixing ratio suitably according to the composition of the raw material used so that content in the baked product A to be obtained may fall within the scope of the present invention.

  The fired product A of component (A) can be produced by appropriately mixing and firing the above raw materials. The method for mixing the raw materials is not particularly limited, and may be performed using a conventional apparatus or the like. Moreover, 1000-1350 degreeC is preferable and the firing temperature at the time of baking has more preferable 1150-1350 degreeC. If the firing temperature is less than 1000 ° C, it may be difficult to reduce the amount of free lime, and if it exceeds 1350 ° C, the raw material mixture may be melted.

  The apparatus used for baking is not specifically limited, For example, a rotary kiln etc. can be used. Moreover, when baking using a rotary kiln, a fuel alternative waste, for example, waste oil, a waste tire, a waste plastic, etc. can also be used.

  In addition, when there are many free limes (free lime) in the baked product A, there is a possibility of expansion and destruction when used as a concrete aggregate. Therefore, the amount of free lime in 100% by mass of the fired product A is preferably 0.4% by mass or less, more preferably 0.2% by mass or less, and further preferably 0.1% by mass or less.

The weight of the fired product A of component (A) is preferably 900 to 1350 g / L, more preferably 1000 g / L or more and less than 1250 g / L from the viewpoint of improving crush resistance and realizing high crushing strength. is there. In addition, the capacity means the following formula (X) from the mass when the measurement container shown in FIG. 1 (internal volume 250 mL) and the funnel are filled with the fired product through the funnel and the mass of the measurement container itself. ).
Weight (g / L) = (mass of measurement container filled with fired product (g) −mass of measurement container itself (g)) × 4.0 (X)

More specifically, the measurement container and the funnel have the shape and dimensions shown in FIG. 1, and the material and thickness are not particularly limited.
Using standard mesh sieves 9.5 mm and 4.75 mm specified in JIS Z 8801, or plate sieves equivalent to these, screen 2 kg of fired product, pass through 9.5 mm sieve, and particle size of 4.75 mm sieve residue The fired product is used as a sample. As shown in FIG. 2, the fired product sample is gently poured onto the funnel inserted in the measurement container. Then carefully, gently raise the funnel. If the fired product A is clogged in the funnel leg and does not flow smoothly, the procedure is repeated from the operation of filling the sample into the container.

  After pulling up the funnel, the surface of the sample in the container is leveled with a fingertip so that the protruding portion and the recessed portion are at the same level. When the filling of the sample is completed, the mass of the container is accurately measured to the 1 g unit, and the weight value is calculated by the above formula. In principle, the weight is measured twice, and the average value is used, but the difference between the two measured values must be within 20 g / L.

  The water absorption rate of the fired product A of the component (A) is preferably 5% or less, more preferably 3.5% or less from the viewpoint of improving stability while maintaining high crushing strength and wear resistance in the fired product A. is there. The water absorption means a value measured according to “JIS A 1110 (Coarse aggregate density and water absorption test method)”.

  The amount of wear reduction of the fired product A of component (A) is preferably 30% or less, more preferably 25% or less, from the viewpoint of imparting good wear resistance while maintaining high crushing strength in the fired product. More preferably, it is 20% or less.

  The particle size of the fired product A of the component (A) is preferably 0.1 to 100 mm from the viewpoint of being suitably used as the above-mentioned civil engineering / portal material, and particularly when used as a coarse aggregate, It is preferable to adjust the particle size to 5 mm or more.

The magnesium-containing insolubilizing material of component (B) used in the present invention contains a specific powder (b-1) made of a magnesium-based material (powder (b-1)). Such powder (b-1) has the following conditions (i) to (ii):
(I) A calcined product B containing magnesium oxide and magnesium carbonate obtained by calcining a mineral mainly composed of magnesium carbonate at 650 to 1,000 ° C. so that a part of the calcined product B becomes magnesium hydroxide. And (ii) the ignition loss rate at 1,000 ° C. is 6 to 30% by mass.
It consists of a magnesium-based material that satisfies
That the magnesium-based material satisfies the condition (i), that is, the magnesium-based material used in the component (B) is magnesium oxide obtained by firing a mineral mainly composed of magnesium carbonate at 650 to 1,000 ° C. It means that the fired product B containing magnesium carbonate is hydrated so that a part of the fired product B becomes magnesium hydroxide.

  In addition, since the said magnesium-type material hydrates a part of baking products containing magnesium oxide and magnesium carbonate, it contains three types of magnesium compounds, magnesium oxide, magnesium carbonate, and magnesium hydroxide.

  By using the magnesium-based material thus obtained, when mixed with the component (A), a high suppression effect on the elution of fluorine can be obtained. For example, a simple mixture of magnesium oxide powder, magnesium carbonate powder, and magnesium hydroxide powder that are obtained individually cannot achieve the excellent effects of the present invention.

  Examples of minerals mainly composed of magnesium carbonate include magnesite and dolomite. In this case, the content of magnesium carbonate in the mineral is preferably 80% by mass or more, more preferably 85% by mass or more, and further preferably 90% by mass or more.

Calcination when obtaining the baked product B is performed such that a part of the mineral mainly composed of magnesium carbonate becomes magnesium oxide and the remainder remains as magnesium carbonate. The temperature at the time of baking is 650-1,000 degreeC, Preferably it is 750-900 degreeC, More preferably, it is 800-900 degreeC. When the temperature is lower than 650 ° C., magnesium oxide is hardly generated. When the temperature exceeds 1,000 ° C., the effect of suppressing elution of fluorine decreases.
In firing, the ratio of magnesium oxide and magnesium carbonate contained in the fired product B can be appropriately adjusted depending on the time and temperature.

  The firing time for obtaining the fired product B is preferably 30 to 240 minutes, more preferably 60 from the viewpoint of obtaining a magnesium-based material that can sufficiently obtain the effects of the present invention when a firing means such as a kiln is used. -210 minutes, more preferably 90-180 minutes. In addition, since it can heat uniformly when using the electric furnace for experiment which is used by the below-mentioned Example, a preferable baking time may be shorter than the case where a kiln is used, for example, is 30 to 90 minutes. .

The method for hydrating the obtained fired product B is not particularly limited, and examples thereof include the following method (i-1) or (i-2).
(I-1) Method of adding water to the fired product B and mixing (i-2) Method of holding the fired product B in an environment of relative humidity of 80% or more for one week or more. When the magnesium-containing insolubilizing material of the component (B) includes the powder (b-2), the hydration reaction may be performed after mixing the fired product B and the powder (b-2). Moreover, before the hydration reaction, it is preferable to grind the fired product B (or a mixture of the fired product B and the powder (b-2)).

The magnesium-based material used in the present invention contains three kinds of magnesium compounds of magnesium oxide, magnesium carbonate, and magnesium hydroxide.
The content of magnesium oxide is preferably 35 to 91.5% by mass, more preferably 45 to 87% by mass, even more preferably 55 to 85% by mass, with the total amount of the magnesium-based material being 100% by mass. is there.
The content of magnesium carbonate is preferably 5 to 55% by mass, more preferably 7 to 50% by mass, and further preferably 8 to 30% by mass, based on the total amount of the magnesium-based material as 100% by mass.
The content of magnesium hydroxide is preferably 3.5 to 30% by mass, more preferably 5 to 20% by mass, even more preferably 7 to 15% by mass, with the total amount of the magnesium-based material being 100% by mass. It is.
By making the contents of magnesium oxide, magnesium carbonate, and magnesium hydroxide within the above ranges, a high suppression effect on the elution of fluorine can be obtained, and the solid content of the magnesium-containing insolubilized material of component (B) can be obtained. Since ligation can be prevented, excellent workability can be obtained.

That a magnesium-type material satisfy | fills condition (i) means that the ignition loss rate in 1000 degreeC of a magnesium-type material is a thing of 6-30 mass%.
The ignition loss rate is 6 to 30% by mass, preferably 6 to 24% by mass, and more preferably 6 to 18% by mass. When the ignition loss ratio is less than 6% by mass or more than 30% by mass, the effect of suppressing the elution of fluorine is lowered, and in particular, the elution of fluorine cannot be sufficiently suppressed in the fired product A having a high contamination concentration. There is.

  In addition to powder (b-1), the magnesium-containing insolubilizing material of component (B) includes (b-2) calcium carbonate, blast furnace slag, magnesium hydroxide, calcium phosphate, calcium sulfate, zeolite, gypsum and phosphorus as required. A powder (powder (b-2)) made of at least one material selected from the group consisting of calcium oxymonohydrogen dihydrate can be included. By blending an appropriate amount of the powder (b-2), the effect of suppressing fluorine elution can be further improved, and the effect of preventing consolidation of the insolubilized material can be enhanced, thereby further improving workability.

  Calcium carbonate, which is a material of powder (b-2), is not particularly limited, but for example, industrial calcium carbonate, reagent calcium carbonate, limestone powder, ground shell of calcium carbonate, coral ground Things can be used. Among these, limestone powder is preferable from the viewpoint of cost.

  Examples of the gypsum that is a material of the powder (b-2) include anhydrous gypsum, dihydrate gypsum, and half-water gypsum, and natural gypsum, various by-product gypsum, gypsum board waste, and the like can be used. When gypsum is added to magnesium oxide, it is preferable to mix it beforehand so that workability is improved. When gypsum is used, the compressive strength is remarkably increased, a practically sufficient solidification strength can be expressed, and the fluorine elution amount can be further reduced. The addition amount of gypsum is preferably 1 to 50 parts by mass with respect to 100 parts by mass in total of magnesium oxide and magnesium hydroxide in the magnesium-containing insolubilized material of component (B).

  Examples of the calcium monohydrogen phosphate dihydrate that is a material of the powder (b-2) include industrial calcium monohydrogen phosphate dihydrate powder, feed calcium monohydrogen phosphate dihydrate powder, and food additives. For example, calcium monohydrogen phosphate dihydrate powder and reagent reagent calcium monohydrogen phosphate dihydrate powder can be used. By using calcium monohydrogen phosphate dihydrate, the amount of elution of fluorine can be further reduced. From the viewpoint of cost, the addition amount of calcium monohydrogen phosphate dihydrate is preferably 0.1 to 20 with respect to a total of 100 parts by mass of magnesium oxide and magnesium hydroxide in the magnesium-containing insolubilized material of component (B). It is a mass part, More preferably, it is 0.2-10 mass parts, More preferably, it is 0.5-6 mass parts.

In the production process of the magnesium-containing insolubilized material of the component (B), the powder (b-2) is (iii) an average particle diameter of 1 to 20 mm (preferably 2 to 10 mm), or (iv) a brain specific surface area of 3,000 to 12,000cm ² / g (preferably 4,000~10,000cm ² / g) is preferably used to adjust the particle size so that. In the case of (iii), it is preferable to mix with the powder (b-1) before hydration and pulverize these two materials at the same time, and then subject to hydration, and in the case of (iv) Is preferably mixed with the powder (b-1) before hydration whose particle size has been adjusted, and then subjected to hydration.

  The blending amount of the powder (b-2) is preferably 40% by mass or less, more preferably 30% by mass or less, and further preferably 20% in the total amount of 100% by mass of the magnesium-containing insolubilized material of the component (B). It is below mass%. If the blending amount exceeds 40% by mass, the content of the powder (b-1) decreases accordingly, and the effect of suppressing the elution of fluorine may be reduced, which is not preferable. In addition, the blending amount of the powder (b-2) is preferably 100% by weight or more in the total amount of the magnesium-containing insolubilized material of the component (B) from the viewpoint of sufficiently obtaining the effect of the powder (b-2). More preferably, it is 3 mass% or more, More preferably, it is 5 mass% or more.

Powder containing powder (b-1) and powder (b-2) in the magnesium-containing insolubilized material of component (B) (however, when powder (b-2) is not included, only powder (b-1)) powder) composed of, the Blaine specific surface area of preferably from 4,500~7,000cm ² / g, more preferably 5,000~6,500cm ² / g. By adjusting the particle size constitution of the component (B) as described above, the effect of suppressing the elution of fluorine can be increased, and the amount of elution of fluorine in the fired product A of the component (A) may be increased more than necessary. Even in this case, elution of fluorine can be effectively suppressed while the content of the component (B) is small.

  In addition, a powder containing powder (b-1) and powder (b-2) in the magnesium-containing insolubilized material of component (B) (however, if powder (b-2) is not included, powder (b-1) )) Has an average particle diameter of preferably 20 to 40 μm, and more preferably 25 to 40 μm. When the average particle size is within the above range, the effect of suppressing the elution of fluorine can be enhanced, and the amount of elution of fluorine in the fired product A of the component (A) may be unnecessarily large. While the content of component (B) is small, elution of fluorine can be effectively suppressed.

In addition, an average particle diameter can be measured using Nikkiso Co., Ltd. 9320-X10 (particle size distribution measuring apparatus), for example. In the measurement, 0.05 g of a sample is added to 20 ml of a dispersion medium ethanol contained in a 100 ml beaker, and ultrasonic dispersion is performed for 1 minute using an ultrasonic cleaning machine (VS-100, frequency 50 kHz) manufactured by ASONE. Measurement will be performed later. The measurement is performed under the condition that the refractive index of the sample is 1.72.
In the present specification, the term “average particle size” means a 50% mass cumulative particle size.

  Furthermore, the powder containing the powder (b-1) and the powder (b-2) in the magnesium-containing insolubilized material of the component (B) (however, if the powder (b-2) is not included, the powder (b-1) It is preferable that there are two peaks in the frequency distribution curve of the particle size obtained by measuring in the same manner as described above. Here, the first peak is preferably in the range of 1 to 5 μm, and the second peak is preferably in the range of 20 to 50 μm.

  The magnesium-containing insolubilizing material of component (B) contains one or more additives (component (b-3)) selected from (b-3) water-soluble sulfate and water-soluble chloride as necessary. Can do. By blending an appropriate amount of the component (b-3), the effect of suppressing the elution of fluorine can be further improved, and the elution of arsenic and hexavalent chromium can also be reduced.

  Examples of the water-soluble sulfate include ferrous sulfate (iron (II) sulfate), aluminum sulfate, potassium aluminum sulfate, sodium aluminum sulfate, tin sulfate and the like. Examples of water-soluble chlorides include ferrous chloride (iron (II) chloride) and ferric chloride (iron (III) chloride). These can be used singly or in combination of two or more. Furthermore, these may be used in the form of powder or in the form of an aqueous solution.

  The compounding amount of the component (b-3) (however, when used as an aqueous solution, it is an amount in terms of solid content. In the case of a hydrate, it is based on the mass excluding hydration water). From the viewpoint of considering that the fluorine elution suppressing effect is not improved even if the amount is too much, and from the viewpoint of cost, it is preferably 50% by mass or less in 100% by mass of the total amount of the magnesium-containing insolubilized material of component (B). More preferably, it is 40 mass% or less. Moreover, the compounding quantity (However, when using as aqueous solution, it is the quantity of solid content conversion. Moreover, when it is a hydrate, it is based on the mass except hydration water.). From the viewpoint of sufficiently obtaining the effect of improving the elution suppression effect of fluorine, the total content of the magnesium-containing insolubilized material (B) is 100% by mass, preferably 1% by mass or more.

  In addition, when using a component (b-3) with the form of a powder, the particle size of this powder is although it does not specifically limit, From viewpoints of workability | operativity etc., 1 mm or less is preferable and 0.5 mm or less is more preferable.

In the case where the magnesium-containing insolubilizing material of component (B) consists only of powder (b-1), a mineral containing magnesium carbonate as a main component is calcined according to the above-mentioned conditions and methods, pulverized as necessary, and calcined. The component (B) can be obtained by partially hydrating the product B (or the pulverized product of the fired product B). Milling, Blaine specific surface area of the pulverized calcined product B obtained is preferably performed such that the 4,500~7,000cm ² / g, more preferably 5,000~6,500cm ² / g.
When the magnesium-containing insolubilizing material of component (B) contains powder (b-2), for example, the insolubilizing material can be obtained by the following methods (v) to (vii).
(V) A step of mixing the fired product B and the material of the powder (b-2) to obtain a mixture, a step of pulverizing the mixture to obtain a pulverized mixture having a predetermined particle size, and pulverization of the mixture Hydrating the product to obtain an insolubilized material containing powders (b-1) and (b-2).
(Vi) A step of pulverizing the fired product B to obtain a pulverized product of the fired product B having a predetermined particle size, and a powder (b-2) having a predetermined particle size by pulverizing the material of the powder (b-2) ), A step of mixing the pulverized product of the fired product B and the powder (b-2) to obtain a mixture, and hydrating the mixture to obtain powders (b-1) and (b-2) And a step of obtaining an insolubilized material.
(Vii) pulverizing the baked product B to obtain a pulverized product of the baked product B having a predetermined particle size; and hydrating the pulverized product of the baked product B to obtain a powder (b-1); The step of pulverizing the material of the powder (b-2) to obtain the powder (b-2) having a predetermined particle size and the powders (b-1) and (b-2) are mixed to obtain an insolubilizing material. Obtaining.
Of these methods, the method (v) or (vi) is preferred, and the method (v) is more preferred, from the viewpoint of fluorine elution suppression effect and workability.

In the method (v), the fired product B before pulverization preferably has a particle size of 1 μm to 50 mm. The material of the powder (b-2) before pulverization preferably has a particle size of 1 μm to 50 mm, more preferably 2 μm to 20 mm. By using the fired product B before pulverization having such a particle size and the material of the powder (b-2), the pulverized product of the mixture, and thus the particle size constitution of the insolubilized material can be easily adjusted.

The baked product B having a particle size of 1 μm to 50 mm and the powder ((b-2) material having a particle size of 1 μm to 50 mm are simultaneously pulverized to form a pulverized product brain comprising a mixture of these two materials When the specific surface area 4,500~7,000cm ² / g (preferably 5,000~6,500cm ² / g) is adjusted to the range of a first peak in the range of 1 to 5 [mu] m, the 20~50μm A powder can be obtained that forms a frequency distribution curve of particle size with two peaks with a second peak in the range, where the ratio of the second peak (frequency%) / first peak (frequency%) is , Preferably 2-4.
In the method (v), the fired product B and the material of the powder (b-2) are pulverized at the same time. Therefore, compared with the method (vi) or (vii) in which these are pulverized separately, Has the advantage of being simple.

In the above method (vi) or (vii), the calcined product B is Blaine specific surface area is preferably 4,500~7,000cm ² / g, more preferably a 5,000~6,500cm ² / g So that it is crushed. The material powder (b-2) is Blaine specific surface area of preferably 3,000~7,000cm ² / g, more preferably ground to a 4,000~6,000cm ² / g. By mixing the pulverized product (or a partially hydrated product) of the fired product B having such a specific surface area and the powder (b-2), an insolubilized material having the above preferred particle size configuration can be obtained. .
In addition, when the material of baked material B and powder (b-2) has the said Blaine specific surface area, it can use as it is, without grind | pulverizing.

  The amount of the magnesium-containing insolubilizing material of component (B) depends on the properties and construction conditions of the fired product A of component (A), the elution amount of fluorine, the required performance of earthwork materials, etc., but usually component (A) 0.5-20 mass parts is preferable with respect to 100 mass parts of baked product A, and 1-15 mass parts is more preferable.

As a method for adding the magnesium-containing insolubilizing material of component (B), dry addition (combusted product is in a wet state or rainwater) in which component (B) is added as powder to component (A) calcined product A and mixed. Water supply), mixing of materials other than water and mixing by adding water, or addition of slurry as a slurry by adding water and mixing can be employed. When adding water, 1-20 mass parts is preferable with respect to 100 mass parts of baked products A, and the addition amount (originally adhering water is included), and 2-15 mass parts is more preferable. If the amount of water added exceeds 20 parts by mass, the slurry water containing the solidifying material may be separated and a sufficient insolubilizing effect may not be obtained.
When only component (b-3) is used in an aqueous solution, powder (b-1) or a mixture of powder (b-1) and powder (b-2) and component (b-3) are separately fired. It can also be added to product A.

  Mixing of the fired product A of the component (A) and the magnesium-containing insolubilized material of the component (B) is a slurry-based mechanical stirring mixing for a deep layer, a powder-based mechanical stirring mixing for a deep layer, a powder-based mechanical stirring mixing for a deep layer, and a high pressure for a deep layer. It can be carried out in the same manner as usual ground improvement such as spray stirring and mixing, backhoe mixing, stabilizer mixing, special backhoe mixing, processing yard mixing, and plant mixing with various mixers. Moreover, the apparatus used for mixing is not specifically limited, You may use a batch type bread mixer, a ribbon mixer; or a continuous paddle mixer, a ribbon mixer, or a rotary mixer. Further, the mixing time is not particularly limited, and may be an optimum mixing time depending on the apparatus to be used. The mixing time is usually 10 seconds or longer, preferably 30 seconds or longer, more preferably 60 seconds or longer.

  The earthwork material composition of the present invention effectively reduces the fluorine elution amount and exhibits high crushing strength while having high safety that can sufficiently satisfy environmental standards. Specifically, the effect of reducing the fluorine elution amount in such a composition can be determined by using, for example, the fluorine elution suppression rate (%) obtained by the following formula (Y) as an index.

Fluorine elution suppression rate (%) = [{Fluorine elution amount in fired product A of component (A) before containing magnesium-containing insolubilizing material of component (B)}-{Component (A ) Calcination product A and the component (B) magnesium eluent in the earthwork material composition containing the magnesium-containing insolubilizing material}] / {sintering the component (B) before the magnesium-containing insolubilizing material is contained Fluorine elution amount in product A} × 100 (%) (Y)
The fluorine elution amount means a value measured in accordance with 2003 Ministry of the Environment Notification No. 18 (elution test based on the Soil Contamination Countermeasures Law). Storage means a temperature of 20 ° C. and a relative humidity of 60%. It means to stand under the constant temperature and humidity conditions.

  For example, the earthwork material composition of the present invention is obtained by mixing the fired product A of the component (A) and the magnesium-containing insolubilized material of the component (B) to obtain the earthwork material composition and storing it for one day. The inhibition rate (%) is preferably 30% or more, and more preferably 50% or more. That is, a sufficient effect can be exhibited only by storing for at least one day.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

[Production Example 1: Production of fired product A of component (A)]
Using limestone, clay, sewage sludge, earth, barite, waste gypsum board, calcium hydrogen phosphate and waste glass, the mineral composition shown in Table 1 (C ₂ AS, C ₄ AF and C ₂ S100 parts by mass) parts by weight of C ₃ a), and barium, zinc, and produce _{SO 3, P 2 O 5,} Na 2 O and calcined product a is the content of free lime (wt% in the calcined product in A100 wt%). The fired product No. 10 was manufactured without using a barium raw material and a zinc raw material. Firing was performed at 1250 to 1350 ° C. using a small rotary kiln. At this time, in addition to general heavy oil, waste oil and waste plastic were used as fuel.

(2) Evaluation of physical properties of fired product A The obtained fired product A was evaluated for weight, water absorption, wear loss and crush resistance. The results are shown in Table 1.

(I) Weight (g / L)
It calculated | required by said formula (X) according to said measuring method using the standard net | network prescribed | regulated to JISZ8801.

  (Ii) Water Absorption Rate (%) Measured according to JIS A 1110 (Coarse Aggregate Density and Water Absorption Test Method).

(Iii) Abrasive weight loss (%)
The measurement was performed according to JIS A 1121 (Coarse aggregate test method using a Los Angeles testing machine).

(Iv) Crush resistance (prevention of dusting): 0.6 mm passage (mass%)
About 5 kg of the obtained fired product A was pulverized with a large jaw crusher adjusted to a lower interval of about 10 mm. Next, the pulverized fired product A was passed through a sieve having an opening of 9.52 mm, and the sample on the sieve was further pulverized with a small jaw crusher adjusted to a lower interval of about 3 mm. The obtained sieve passage and the sample crushed with a small jaw crusher were mixed and weighed 4.0 kg. The weighed sample was added to a ball mill together with 1.8 mL of a grinding aid diethylene glycol, and after 500 rotations at 70 rpm, the samples were discharged at 50 rotations. The obtained pulverized product was measured for 0.6 mm passage (mass%) and used as an index for evaluating the pulverization resistance and dusting prevention effect. It can be determined that the smaller the value of the passing portion, the higher the pulverization resistance, and the better the fired product obtained by effectively preventing dusting.
The results are shown in Table 1.

In addition, about the baked product No. 1-8, when the passage part of the 100 micrometer sieve was confirmed, the powdery part of this passage part did not exist.
Moreover, about baked product No. 9, dusting generate | occur | produced partially and the powdery material for the passage of a 100 micrometer sieve was 33 mass%.
The fluorine content of the fired product No. 8 was 0.025% by mass.

From the results of Table 1, 10 to 100 parts by mass of C ₂ AS, 20 parts by mass or less of C ₃ A and 0.02 to 0.2% by mass of barium with respect to 100 parts by mass of C ₂ S, zinc It can be seen that the fired products Nos. 1 to 8 containing 0.03 to 0.5% by mass exhibit excellent crush resistance while having a high weight, and also have good physical properties.

[Production Example 2: Production of magnesium-containing insolubilized material of component (B)]
Magnesite (magnesium carbonate content: 95% by mass) was fired at 850 ° C. for 30 minutes using an experimental electric furnace to obtain a fired product B containing magnesium oxide and magnesium carbonate. Next, the obtained fired product B was pulverized to obtain a pulverized product of fired product B having a Blaine specific surface area of 5,500 cm ² / g.

  The obtained pulverized product B was stored in a storage room with a relative humidity of 100% for 10 days to hydrate a part thereof, thereby obtaining a magnesium-containing insolubilized material (1) as component (B). About the obtained insolubilization material (1), the component composition, the brain specific surface area, the average particle diameter, and the ignition loss rate were calculated | required with the following method. The results are shown in Table 2.

<Ingredient composition>
Calculated from X-ray diffraction, thermogravimetric analysis and chemical analysis values.

<< Brain specific surface area >>
It measured according to "JISR5201".

《Average particle size》
In a 100 ml beaker, 20 ml of ethanol (dispersion medium) and 0.05 g of an insolubilizing material were added, and ultrasonically dispersed for 1 minute using an ultrasonic cleaner (VS-100, frequency 50 kHz) manufactured by ASONE. Then, the average particle diameter (50% mass cumulative particle diameter) was calculated | required using Nikkiso Co., Ltd. 9320-X10 (particle size distribution measuring apparatus). Note that the refractive index of the sample is assumed to be 1.72.

《Ignition loss rate》
The ignition temperature was measured at 1,000 ° C. according to “JIS R 5202 Portland cement chemical analysis method 8. Determination method of ignition loss”.

[Examples 1 to 3, Comparative Example 1]
Using the fired product No. 4 (50 kg) obtained in Production Example 1, the amount of fluorine eluted was measured according to the Ministry of the Environment Notification No. 18 method. Next, the insolubilized material (1) and water obtained in Production Example 2 were added to the calcined product No. 4 in the amounts shown in Table 3, and these were added all at once to a batch-type biaxial paddle mixer (60 L). And mixed for 30 seconds.
The resulting mixture was stored under conditions of a temperature of 20 ° C. and a relative humidity of 60%. The amount of fluorine eluted after 1 to 7 days of storage was measured according to the Ministry of the Environment Notification No. 18 method. The environmental standard value of fluorine is 0.8 mg / liter.
Based on the above formula (Y), the fluorine elution suppression rate (%) was determined from the fluorine elution amount before adding the insolubilizing material (1) and the fluorine elution amount measured after storage. The results are shown in Table 3.

  From the results in Table 3, it can be seen that the compositions of Examples 1 to 3 can exhibit a fluorine elution suppression effect that can sufficiently satisfy the environmental standards as compared with the composition of Comparative Example 1.

Claims (10)

The following components (A) and (B):
(A) relative to 2CaO · SiO ₂ 100 parts by mass, the _{2CaO · Al 2 O 3 · SiO} 2 containing 10 to 100 parts by weight, and firing the content of 3CaO · Al ₂ O ₃ is not more than 20 parts by weight A calcined product A containing 0.02 to 0.2% by mass of barium and 0.03 to 0.5% by mass of zinc in 100% by mass of the calcined product, and (B) carbonic acid A fired product B containing magnesium oxide and magnesium carbonate obtained by firing a magnesium-based mineral at 650 to 1,000 ° C. was hydrated so that a part of the fired product B was magnesium hydroxide. An earthwork material composition comprising a magnesium-containing insolubilizing material containing a powder made of a magnesium-based material having a loss on ignition at 1,000 ° C. of 6 to 30% by mass.   The component (B) further contains a powder comprising at least one selected from the group consisting of calcium carbonate, blast furnace slag, magnesium hydroxide, calcium phosphate, calcium sulfate, zeolite, gypsum, and calcium monohydrogen phosphate dihydrate. Item 2. The earthwork material composition according to Item 1.   The earthwork material composition of Claim 1 or 2 which contains 0.5-20 mass parts of components (B) with respect to 100 mass parts of components (A). The earthwork material composition according to any one of claims 1 to ₃ , wherein the content of SO ₃ in 100% by mass of component (A) is 1.5% by mass or less. The earthwork material composition according to claim 1, wherein the content of P ₂ O ₅ in 100% by mass of the component (A) is 0.3% by mass or more. The content of P ₂ O ₅ in 100% by mass of component (A) is less than 0.3% by mass, and 1.0 to 5.0% by mass of K ₂ O and / or Na ₂ O is contained in total. The earthwork material composition according to any one of claims 1 to 5. The earthwork material composition according to any one of claims 1 to 6, wherein a part of 2CaO · Al ₂ O ₃ · SiO ₂ is substituted with 4CaO · Al ₂ O ₃ · Fe ₂ O ₃ .   The earthwork material composition according to any one of claims 1 to 7, wherein a weight of the component (A) is 900 g / L or more and less than 1250 g / L. The following components (A) and (B):
(A) relative to 2CaO · SiO ₂ 100 parts by mass, the _{2CaO · Al 2 O 3 · SiO} 2 containing 10 to 100 parts by weight, and firing the content of 3CaO · Al ₂ O ₃ is not more than 20 parts by weight A calcined product A containing 0.02 to 0.2% by mass of barium and 0.03 to 0.5% by mass of zinc in 100% by mass of the calcined product, and (B) carbonic acid A fired product B containing magnesium oxide and magnesium carbonate obtained by firing a magnesium-based mineral at 650 to 1,000 ° C. was hydrated so that a part of the fired product B was magnesium hydroxide. Fluorine elution amount in an earthwork material composition comprising a step of mixing a magnesium-containing insolubilized material containing a powder made of a magnesium-based material having a loss on ignition at 1,000 ° C. of 6 to 30% by mass The low How to reduce.   The method to reduce the fluorine elution amount in the earthwork material composition of Claim 9 including the process of mixing 0.5-20 mass parts of components (B) with respect to 100 mass parts of components (A).