JP2018203564A - Reduction treatment method for chromium oxide-containing substance, and production method of civil engineering works material - Google Patents
Reduction treatment method for chromium oxide-containing substance, and production method of civil engineering works material Download PDFInfo
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Abstract
Description
本発明は、クロム酸化物含有物質の還元処理方法および土木工事用材料の製造方法に関する。 The present invention relates to a method for reducing a chromium oxide-containing substance and a method for producing a material for civil engineering work.
ステンレス鋼スラグ、クロム鉱滓などのスラグは、数％のクロム酸化物を含有し、操業条件によっては、その一部はＣｒ６＋にまで酸化し、Ｃｒ６＋が溶出する場合がある。
ステンレス鋼スラグ、クロム鉱滓などのスラグを、路盤材、仮設道路材、埋立て材などの土木工事用材料として使用する場合、スラグからＣｒ６＋が溶出しないことが絶対条件である。
Stainless steel slag, slag such as chromium slag contains a few percent of chromium oxide, by operating conditions, a portion thereof is oxidized to the Cr 6+, which may Cr 6+ elutes.
When using slag such as stainless steel slag and chromium slag as civil engineering materials such as roadbed materials, temporary road materials, and landfill materials, it is an absolute condition that Cr 6+ does not elute from the slag.
また、近年、ゴミ焼却灰、下水汚泥などを溶融処理することによってスラグ化し、生成したスラグを路盤材などとして有効利用することが検討されている。しかし、ゴミ焼却灰、下水汚泥などの種類によっては、生成したスラグからＣｒ６＋が溶出する場合がある。この場合、ゴミ焼却灰、下水汚泥などの有効利用が困難になる。
さらに、建設廃材として発生するコンクリート破砕物からもＣｒ６＋が溶出することがある。
In recent years, it has been studied to make slag by melting trash incineration ash, sewage sludge, and the like and to effectively use the generated slag as roadbed material. However, depending on the type of garbage incineration ash, sewage sludge, etc., Cr 6+ may be eluted from the generated slag. In this case, effective utilization of refuse incineration ash, sewage sludge, etc. becomes difficult.
Furthermore, Cr 6+ may be eluted from concrete crushed material generated as construction waste.
そこで、従来、これらのクロム酸化数含有物質からＣｒ６＋が溶出することを防止するため、クロム酸化数含有物質に対して還元処理を施す技術が開発されている。
例えば、特許文献１の［請求項１０］には、「クロム酸化物含有物質と、硫黄および／または酸化数が＋５価以下の硫黄を含有するスラグと、硫黄および／または酸化数が＋５価以下の硫黄を含有する物質とを混合し、該混合物に水蒸気を吹き込むことを特徴とするクロム酸化物含有物質の処理方法」が開示されている。
Therefore, in order to prevent Cr 6+ from eluting from these chromium oxidation number-containing substances, techniques for reducing the chromium oxidation number-containing substances have been developed.
For example, in [Claim 10] of Patent Document 1, “chromium oxide-containing material, slag containing sulfur and / or sulfur having an oxidation number of +5 or less, and sulfur and / or oxidation number of +5 or less. And a method for treating a chromium oxide-containing material, characterized in that water is blown into the mixture.
しかし、本発明者が検討した結果、特許文献１に記載された処理方法では、還元処理後のクロム酸化物含有物質のＣｒ６＋溶出量を十分に低減できない場合があった。 However, as a result of examination by the present inventors, the treatment method described in Patent Document 1 sometimes fails to sufficiently reduce the Cr 6+ elution amount of the chromium oxide-containing material after the reduction treatment.
本発明は、以上の点を鑑みてなされたものであり、Ｃｒ６＋溶出量をより低減できるクロム酸化物含有物質の還元処理方法を提供することを目的とする。
さらに、本発明は、上記還元処理方法により還元処理が施されたクロム酸化物含有物質を用いた土木工事用材料の製造方法を提供することも目的とする。
This invention is made | formed in view of the above point, and it aims at providing the reduction | restoration processing method of the chromium oxide containing material which can reduce Cr6 + elution amount more.
Furthermore, another object of the present invention is to provide a method for producing a material for civil engineering work using a chromium oxide-containing material that has been subjected to reduction treatment by the reduction treatment method.
本発明者らは、鋭意検討した結果、下記構成を採用することにより、上記目的が達成されることを見出した。 As a result of intensive studies, the present inventors have found that the above object can be achieved by adopting the following configuration.
すなわち、本発明は、以下の［１］〜［８］を提供する。
［１］クロム酸化物含有物質に、上記クロム酸化物含有物質の吸水率に対して５０％以上の水を含ませ、上記水を含ませた上記クロム酸化物含有物質と、酸化数が＋５価以下の硫黄を含有する物質とを混合し、上記混合により得られた混合物に水蒸気を吹き込む、クロム酸化物含有物質の還元処理方法。
［２］クロム酸化物含有物質と、酸化数が＋５価以下の硫黄を含有する物質とを混合し、上記混合により得られた混合物に、上記クロム酸化物含有物質の吸水率に対して５０％以上の水を含ませ、上記水を含ませた上記混合物に水蒸気を吹き込む、クロム酸化物含有物質の還元処理方法。
［３］上記酸化数が＋５価以下の硫黄を含有する物質が、高炉徐冷スラグおよび脱硫スラグからなる群から選ばれる少なくとも１種である、上記［１］または［２］に記載のクロム酸化物含有物質の還元処理方法。
［４］上記クロム酸化物含有物質の吸水率に対して５０％以上含ませる水が、＋５価以下の硫黄含有物質が溶解している水である、上記［１］〜［３］のいずれかに記載のクロム酸化物含有物質の還元処理方法。
［５］上記＋５価以下の硫黄含有物質が溶解している水が、高炉スラグの散水冷却時に発生する高炉スラグ溶出水である、上記［４］に記載のクロム酸化物含有物質の還元処理方法。
［６］上記［１］〜［５］のいずれかに記載の還元処理方法により還元処理が施されたクロム酸化物含有物質１００質量部に、５質量部以上の硫黄含有スラグを配合することにより、土木工事用材料を得る、土木工事用材料の製造方法。
［７］上記硫黄含有スラグが、高炉徐冷スラグおよび脱硫スラグからなる群から選ばれる少なくとも１種である、上記［６］に記載の土木工事用材料の製造方法。
［８］上記土木工事用材料が、路盤材、仮設道路材、埋立て材および地盤改良材からなる群から選ばれる少なくとも１種である、上記［６］または［７］に記載の土木工事用材料の製造方法。
That is, the present invention provides the following [1] to [8].
[1] The chromium oxide-containing material contains 50% or more of water with respect to the water absorption rate of the chromium oxide-containing material, the chromium oxide-containing material containing the water, and an oxidation number of +5 A method for reducing a chromium oxide-containing material, comprising mixing the following sulfur-containing material and blowing water vapor into the mixture obtained by the above mixing.
[2] Mixing a chromium oxide-containing substance and a substance containing sulfur having an oxidation number of +5 or less, and adding 50% to the water absorption of the chromium oxide-containing substance in the mixture obtained by the above mixing A method for reducing a chromium oxide-containing substance, comprising the above-described water and blowing water vapor into the mixture containing the water.
[3] The chromium oxidation according to the above [1] or [2], wherein the substance containing sulfur having an oxidation number of +5 or less is at least one selected from the group consisting of blast furnace slow cooling slag and desulfurization slag Reduction method of substance-containing material.
[4] Any of the above [1] to [3], wherein the water to be contained by 50% or more with respect to the water absorption rate of the chromium oxide-containing substance is water in which a sulfur-containing substance having a valence of +5 or less is dissolved. The reduction | restoration processing method of the chromium oxide containing material of description.
[5] The method for reducing a chromium oxide-containing material according to the above [4], wherein the water in which the sulfur-containing material having a valence of +5 or less is dissolved is blast furnace slag elution water generated during sprinkling cooling of the blast furnace slag. .
[6] By blending 5 parts by mass or more of sulfur-containing slag with 100 parts by mass of the chromium oxide-containing substance subjected to the reduction treatment by the reduction treatment method according to any one of [1] to [5] above. A method for producing civil engineering materials, obtaining civil engineering materials.
[7] The method for producing a civil engineering material according to [6], wherein the sulfur-containing slag is at least one selected from the group consisting of a blast furnace slow-cooled slag and a desulfurized slag.
[8] The civil engineering material according to [6] or [7], wherein the civil engineering material is at least one selected from the group consisting of a roadbed material, a temporary road material, a landfill material, and a ground improvement material. Material manufacturing method.
本発明によれば、Ｃｒ６＋溶出量をより低減できるクロム酸化物含有物質の還元処理方法を提供することができる。
さらに、本発明によれば、上記還元処理方法により還元処理が施されたクロム酸化物含有物質を用いた土木工事用材料の製造方法を提供することもできる。
ADVANTAGE OF THE INVENTION According to this invention, the reduction processing method of the chromium oxide containing substance which can reduce Cr 6+ elution amount more can be provided.
Furthermore, according to this invention, the manufacturing method of the material for civil engineering works using the chromium oxide containing material by which the reduction process was given by the said reduction process method can also be provided.
［クロム酸化物含有物質の還元処理方法］
本発明のクロム酸化物含有物質の還元処理方法の一態様は、クロム酸化物含有物質に、上記クロム酸化物含有物質の吸水率に対して５０％以上の水を含ませ、上記水を含ませた上記クロム酸化物含有物質と、酸化数が＋５価以下の硫黄を含有する物質とを混合し、上記混合により得られた混合物に水蒸気を吹き込む、クロム酸化物含有物質の還元処理方法である。
また、本発明のクロム酸化物含有物質の還元処理方法の別の一態様は、クロム酸化物含有物質と、酸化数が＋５価以下の硫黄を含有する物質とを混合し、上記混合により得られた混合物に、上記クロム酸化物含有物質の吸水率に対して５０％以上の水を含ませ、上記水を含ませた上記混合物に水蒸気を吹き込む、クロム酸化物含有物質の還元処理方法である。
[Reduction treatment method for chromium oxide-containing substances]
In one embodiment of the method for reducing a chromium oxide-containing substance according to the present invention, the chromium oxide-containing substance contains 50% or more of water with respect to the water absorption rate of the chromium oxide-containing substance, and the water is included. In addition, the chromium oxide-containing substance is mixed with a substance containing sulfur having an oxidation number of +5 or less, and water vapor is blown into the mixture obtained by the above mixing.
Another embodiment of the method for reducing a chromium oxide-containing material according to the present invention is obtained by mixing the chromium oxide-containing material and a material containing sulfur having an oxidation number of +5 or less and mixing the materials. In this method, the chromium oxide-containing substance is reduced by containing 50% or more of water with respect to the water absorption rate of the chromium oxide-containing substance and blowing water vapor into the mixture containing the water.
＜本発明者による知見＞
本発明者の検討によれば、クロム酸化物含有物質を、酸化数が＋５価以下の硫黄を含有する物質を用いて還元処理する際に、クロム酸化物含有物質（の開気孔や表面）に存在する水が還元処理効果に大きな影響を及ぼすことが分かった。
<Knowledge by the Inventor>
According to the study of the present inventor, when the chromium oxide-containing substance is reduced using a substance containing sulfur having an oxidation number of +5 or less, the chromium oxide-containing substance (its open pores and surfaces) is reduced. It was found that the existing water has a great influence on the reduction treatment effect.
図１は、クロム酸化物含有物質の含水率とＣｒ６＋溶出量との関係を示すグラフである。より詳細には、図１は、含水率を変えたクロム酸化物含有物質と、酸化数が＋５価以下の硫黄を含有する物質とを混合し、得られた混合物に水蒸気を吹き込んだ後、環境庁告示第４６号によるＣｒ６＋の溶出試験を行なった結果を示すグラフである。本試験に供したクロム酸化物含有物質の吸水率は、６．４質量％である。吸水率の求め方は後述する。 FIG. 1 is a graph showing the relationship between the moisture content of a chromium oxide-containing substance and the Cr 6+ elution amount. More specifically, FIG. 1 shows a mixture of a chromium oxide-containing substance with a changed moisture content and a substance containing sulfur having an oxidation number of +5 or less, and after blowing water vapor into the resulting mixture, It is a graph which shows the result of having performed the dissolution test of Cr6 + by Agency Notification No. 46. The water absorption of the chromium oxide-containing material used in this test is 6.4% by mass. A method for obtaining the water absorption rate will be described later.
図１のグラフから、クロム酸化物含有物質の含水率を３．２質量％以上とすることにより、Ｃｒ６＋溶出量が定量下限値未満となることが分かる。すなわち、吸水率に対して５０％以上の水を、クロム酸化物含有物質に含ませればよい。 From the graph of FIG. 1, it is understood that the Cr 6+ elution amount becomes less than the lower limit of quantification by setting the water content of the chromium oxide-containing substance to 3.2% by mass or more. That is, 50% or more of water with respect to the water absorption rate may be included in the chromium oxide-containing material.
クロム酸化物含有物質に、その吸水率に対して５０％以上の水を含ませてから、酸化数が＋５価以下の硫黄を含有する物質を混合し、水蒸気を吹き込むと還元しやすい理由は、Ｃｒ６＋の生成メカニズムおよび還元メカニズムの双方が関係している。 The reason why the chromium oxide-containing substance is easy to be reduced when water containing 50% or more of its water absorption ratio is mixed with a substance containing sulfur with an oxidation number of +5 or less and blown with water vapor. Both Cr 6+ formation and reduction mechanisms are involved.
Ｃｒ６＋の生成は、ステンレス鋼スラグ、クロム鉱滓などの高温で溶融状態のクロム酸化物含有物質が、冷却時に固化し、空気中の酸素と反応することにより生成する。すなわち、Ｃｒ６＋はクロム酸化物含有物質の表面や開気孔内に存在することとなる。Ｃｒ６＋は水が存在すると徐々に溶解する。この溶解速度は温度が高いほど速い。 Cr 6+ is produced when a chromium oxide-containing substance in a molten state, such as stainless steel slag or chromium slag, solidifies upon cooling and reacts with oxygen in the air. That is, Cr 6+ is present on the surface of the chromium oxide-containing material and in the open pores. Cr 6+ dissolves gradually in the presence of water. This dissolution rate is faster as the temperature is higher.
一方、Ｃｒ６＋の還元は、＋５価以下の硫黄が還元剤として作用する。この還元剤のうち、高炉徐冷スラグの物質移動について本発明者が調べたところ、水（液体）への溶解が９０質量％、ガスとしての揮発が１０質量％であることが分かった。 On the other hand, in the reduction of Cr 6+ , sulfur having a valence of +5 or less acts as a reducing agent. Among the reducing agents, the present inventors investigated the mass transfer of blast furnace chilled slag, and it was found that dissolution in water (liquid) was 90% by mass and volatilization as a gas was 10% by mass.
これらの現象から、クロム酸化物含有物質の開気孔や表面に水が存在すると、次のようなメカニズムでＣｒ６＋が還元されることから、クロム酸化物含有物質の開気孔や表面に存在する水が還元処理には極めて重要であることが分かった。
（１）クロム酸化物含有物質に水を含ませると、その水にＣｒ６＋が徐々に溶解する。
（２）酸化数が＋５価以下の硫黄を含有する物質を混合し、得られた混合物に水蒸気を吹き込むと、混合物の温度が高くなり、クロム酸化物含有物質からのＣｒ６＋の水への溶解速度が加速する。
（３）それと同時に、＋５価以下の硫黄が水へ溶解する。
（４）水中におけるＣｒ６＋と＋５価以下の硫黄とが反応し、Ｃｒ６＋がＣｒ３＋に還元され無害化する。
（５）一部のＣｒ６＋については、ガスとして揮発した＋５価以下の硫黄により、水を介さずに直接還元され無害化する。
From these phenomena, when water is present on the open pores and the surface of the chromium oxide-containing material, Cr 6+ is reduced by the following mechanism. However, it was found to be extremely important for reduction treatment.
(1) When water is contained in the chromium oxide-containing material, Cr 6+ is gradually dissolved in the water.
(2) When a substance containing sulfur having an oxidation number of +5 or less is mixed and water vapor is blown into the resulting mixture, the temperature of the mixture becomes high, and dissolution of Cr 6+ from the chromium oxide-containing substance into water Speed increases.
(3) At the same time, sulfur of +5 or less is dissolved in water.
(4) Cr 6+ in water reacts with +5 or less valent sulfur, and Cr 6+ is reduced to Cr 3+ and rendered harmless.
(5) Some Cr 6+ is reduced directly and harmless by +5 or less valent sulfur volatilized as a gas without using water.
＜クロム酸化物含有物質＞
還元処理を施すクロム酸化物含有物質としては、特に限定されず、例えば、ステンレス鋼精錬の際に発生するステンレス鋼スラグ；重クロム酸ナトリウムなどのクロム化合物の製造の際に発生するクロム鉱滓；産業廃棄物などの廃棄物を溶融処理することによりスラグ化した廃棄物溶融スラグ；ゴミ焼却灰を溶融処理することによりスラグ化したゴミ焼却灰溶融スラグ；下水汚泥などの汚泥を溶融処理することによりスラグ化した下水汚泥溶融スラグなどの汚泥溶融スラグ；建設廃材として発生するコンクリート破砕物；等が挙げられる。
<Chromium oxide-containing material>
The chromium oxide-containing material subjected to reduction treatment is not particularly limited. For example, stainless steel slag generated during refining of stainless steel; chromium slag generated during the manufacture of chromium compounds such as sodium dichromate; Waste melting slag converted into slag by melting waste such as waste; Waste incinerated ash melting slag converted into slag by melting waste incineration ash; Slag by melting sludge such as sewage sludge Sludge melted slag such as sewage sludge melted slag; concrete crushed material generated as construction waste;
＜クロム酸化物含有物質の吸水率＞
クロム酸化物含有物質の吸水率は、次の方法により求める。
まず、試料（クロム酸化物含有物質）を５ｍｍの篩で篩分ける。その後、篩下の−５ｍｍの試料については、ＪＩＳ Ａ １１０９「細骨材の密度及び吸水率試験方法」により吸水率を測定する。篩上の＋５ｍｍの試料については、ＪＩＳ Ａ １１１０「粗骨材の密度及び吸水率試験方法」により吸水率を測定する。得られた測定値から、＋５ｍｍと−５ｍｍとの比率をもとに、試料の吸水率を求める。
<Water absorption of chromium oxide-containing material>
The water absorption rate of the chromium oxide-containing material is determined by the following method.
First, a sample (chromium oxide-containing substance) is sieved with a 5 mm sieve. Then, about the sample of -5 mm under a sieve, a water absorption is measured by JIS A1109 "The density and water absorption test method of a fine aggregate." For the +5 mm sample on the sieve, the water absorption is measured according to JIS A 1110 “Coarse Aggregate Density and Water Absorption Test Method”. From the obtained measured value, the water absorption rate of the sample is obtained based on the ratio of +5 mm to −5 mm.
＜含水の時期＞
水蒸気は固液共存であることから少量の液体の水が供給されるが、上述したように、水蒸気を吹き込む前に存在する水が還元処理に影響する。
したがって、クロム酸化物含有物質に水を含ませる時期（含水の時期）は、水蒸気を吹き込む前であれば特に限定されず、クロム酸化物含有物質と酸化数が＋５価以下の硫黄を含有する物質とを混合する前後のどちらでもよい。
すなわち、酸化数が＋５価以下の硫黄を含有する物質と混合する前のクロム酸化物含有物質に水を含ませてもよいし（混合前）、クロム酸化物含有物質と酸化数が＋５価以下の硫黄を含有する物質とを混合して得られた混合物に水を含ませてもよい（混合後）。
<Time of water content>
Since water vapor coexists with solid and liquid, a small amount of liquid water is supplied. However, as described above, water existing before blowing water vapor affects the reduction treatment.
Accordingly, the time when water is added to the chromium oxide-containing material (water-containing time) is not particularly limited as long as it is before blowing water vapor, and the material containing chromium oxide-containing material and sulfur having an oxidation number of +5 or less. Either before or after mixing.
That is, water may be contained in the chromium oxide-containing material before mixing with the sulfur-containing material having an oxidation number of +5 or less (before mixing), or the chromium oxide-containing material and the oxidation number of +5 or less. Water may be included in the mixture obtained by mixing the sulfur-containing substance (after mixing).
＜含水率＞
クロム酸化物含有物質（または、クロム酸化物含有物質と酸化数が＋５価以下の硫黄を含有する物質との混合物）に含ませる水の量（含水率）は、クロム酸化物含有物質の吸水率に対して５０％以上であれば特に限定されない。クロム酸化物含有物質に過剰の水を含水させても（すなわち、クロム酸化物含有物質が表面水を持った状態でも）、図１のグラフに示すように、得られる効果は変わらない。
<Moisture content>
The amount of water (moisture content) contained in the chromium oxide-containing substance (or a mixture of the chromium oxide-containing substance and a substance containing sulfur having an oxidation number of +5 or less) is determined by the water absorption rate of the chromium oxide-containing substance. If it is 50% or more with respect to it, it will not specifically limit. Even when excess water is contained in the chromium oxide-containing material (that is, even when the chromium oxide-containing material has surface water), the obtained effect does not change as shown in the graph of FIG.
ここで、吸水率に対する含水率の定義を説明する。
クロム酸化物含有物質の吸水率が、仮に１０質量％である場合、絶乾状態で１０００ｇのクロム酸化物含有物質を表面乾燥飽水状態とすると１１００ｇとなる。すなわち、１００ｇの水が含まれることとなる。本発明において、例えば、吸水率に対する含水率が５０％の状態とは、５０ｇの水が含まれる状態を表す。式で示すと次のようになる。
吸水率に対する含水率［％］＝（クロム酸化物含有物質の含水率［質量％］／クロム酸化物含有物質の吸水率［質量％］)×１００
Here, the definition of the moisture content with respect to the water absorption rate will be described.
If the water absorption rate of the chromium oxide-containing material is 10% by mass, 1000 g of the chromium oxide-containing material in a completely dry state is 1100 g when the surface is saturated with water. That is, 100 g of water is contained. In the present invention, for example, a state where the water content relative to the water absorption is 50% represents a state where 50 g of water is contained. This is expressed as follows.
Water content [%] with respect to water absorption rate = (water content of chromium oxide-containing material [% by mass] / water absorption rate of chromium oxide-containing material [% by mass]) × 100
＜水＞
クロム酸化物含有物質（または、クロム酸化物含有物質と酸化数が＋５価以下の硫黄を含有する物質との混合物）に含ませる水としては、特に限定されず、例えば、工業用水、井戸水、雨水などを使用できる。
クロム酸化物含有物質が、雨水等がかかることによって吸水率に対して５０％以上の水を含んでいる場合には、新たに水を含ませることは要しない。
＋５価以下の硫黄含有物質が溶解している水であれば、水蒸気を吹き込む前から徐々に還元反応が進むためより効果的である。＋５価以下の硫黄含有物質が溶解している水としては、高炉スラグの散水冷却時に発生する高炉スラグ溶出水を好ましく用いることができる。この水には、Ｓ２Ｏ３ ２−が３０ｇ／Ｌ前後と多く溶解しているからである。
<Water>
The water to be included in the chromium oxide-containing material (or a mixture of the chromium oxide-containing material and a material containing sulfur having an oxidation number of +5 or less) is not particularly limited. For example, industrial water, well water, rainwater Etc. can be used.
When the chromium oxide-containing material contains 50% or more of water absorption due to rainwater or the like, it is not necessary to newly add water.
Water in which a sulfur-containing substance having a valence of +5 or less is dissolved is more effective because the reduction reaction proceeds gradually before steam is blown. As water in which a sulfur-containing substance having a valence of +5 or less is dissolved, blast furnace slag elution water generated during water cooling of the blast furnace slag can be preferably used. This is because a large amount of S 2 O 3 2− is dissolved in this water at around 30 g / L.
＜酸化数が＋５価以下の硫黄を含有する物質（還元剤）＞
酸化数が＋５価以下の硫黄を含有する物質（「還元剤」ともいう）としては、特に限定されないが、高炉徐冷スラグおよび脱硫スラグからなる群から選ばれる少なくとも１種であることが好ましい。高炉徐冷スラグおよび脱硫スラグは、＋５価以下の硫黄で水に溶けやすいＳ２Ｏ３ ２−を多く含むため、好ましく用いることができる。なかでも、生成から時間が経過していない未エージング高炉徐冷スラグは、より好ましく用いることができる。
<Substances containing sulfur with an oxidation number of +5 or less (reducing agent)>
The substance containing sulfur having an oxidation number of +5 or less (also referred to as “reducing agent”) is not particularly limited, but is preferably at least one selected from the group consisting of blast furnace slow-cooled slag and desulfurized slag. Blast furnace slow-cooled slag and desulfurized slag can be preferably used because they contain a large amount of S 2 O 3 2− which is less than +5 valent sulfur and easily dissolved in water. Especially, the non-aging blast furnace slow cooling slag whose time has not passed since production | generation can be used more preferably.
＜クロム酸化物含有物質と還元剤との混合比＞
クロム酸化物含有物質と還元剤（酸化数が＋５価以下の硫黄を含有する物質）との混合比は、特に限定されず、例えば、クロム酸化物含有物質からのＣｒ６＋溶出量と、＋５価以下の硫黄を含有する物質の還元能力とに応じて、適宜設定すればよい。
<Mixing ratio of chromium oxide-containing substance and reducing agent>
The mixing ratio of the chromium oxide-containing material and the reducing agent (the material containing sulfur having an oxidation number of +5 or less) is not particularly limited. For example, the Cr 6+ elution amount from the chromium oxide-containing material and the +5 valence What is necessary is just to set suitably according to the reducing capability of the substance containing the following sulfur.
＜水蒸気の吹き込み＞
水蒸気の吹き込み方法としては、特に限定されず、例えば、混合物の下から水蒸気を吹き込む方法；オートクレーブなどの高圧高温容器中に混合物をさらす方法；などが挙げられる。混合物の下から水蒸気を吹き込む具体的な方法としては、具体的には、例えば、小規模であれば、蒸し器などを用いる方法が挙げられ、大規模であれば、小さな孔を開けた水蒸気の配管上に混合物を積み付け、それをシートで被い、水蒸気を流す方法が挙げられる。
<Blowing steam>
The method of blowing water vapor is not particularly limited, and examples thereof include a method of blowing water vapor from below the mixture; a method of exposing the mixture to a high-pressure and high-temperature vessel such as an autoclave. As a specific method for blowing water vapor from the bottom of the mixture, specifically, for example, a small-scale method using a steamer or the like is used. There is a method in which the mixture is stacked on top, covered with a sheet, and steam is allowed to flow.
［土木工事用材料の製造方法］
本発明の土木工事用材料の製造方法は、上述した本発明のクロム酸化物含有物質の還元処理方法により還元処理（以下、便宜的に「本発明の還元処理」ともいう）が施されたクロム酸化物含有物質１００質量部に、５質量部以上の硫黄含有スラグを配合することにより、土木工事用材料を得る、土木工事用材料の製造方法である。
[Method for manufacturing civil engineering materials]
The method for producing a material for civil engineering work according to the present invention comprises chromium that has been subjected to reduction treatment (hereinafter also referred to as “reduction treatment of the present invention” for the sake of convenience) by the reduction treatment method for a chromium oxide-containing substance of the present invention described above. This is a method for producing a civil engineering material, wherein a civil engineering material is obtained by blending 5 parts by mass or more of sulfur-containing slag with 100 parts by mass of an oxide-containing substance.
本発明の土木工事用材料の製造方法により得られた土木工事用材料においては、Ｃｒ６＋の溶出をより防止できる。
その理由としては、上述した本発明の還元処理によってクロム酸化物含有物質のＣｒ６＋を十分に還元できなかった場合でも、本発明の還元処理後に配合する硫黄含有スラグ中に存在する硫黄成分が水中に溶出して、Ｃｒ６＋を還元するためであると考えられる。
In the civil engineering material obtained by the method for producing a civil engineering material of the present invention, elution of Cr 6+ can be further prevented.
The reason is that the sulfur component present in the sulfur-containing slag to be blended after the reduction treatment of the present invention is not enough even if Cr 6+ of the chromium oxide-containing material cannot be sufficiently reduced by the reduction treatment of the present invention described above. This is thought to be due to the reduction of Cr 6+ .
＜硫黄含有スラグ＞
硫黄含有スラグとしては、例えば、高炉徐冷スラグおよび脱硫スラグからなる群から選ばれる少なくとも１種を用いることが好ましい。高炉徐冷スラグや脱硫スラグなどの硫黄含有スラグ中のＳ０、Ｓ２−、Ｓ２Ｏ３ ２−が水に徐々に溶解し、これらがＳＯ４ ２−まで酸化する際にＣｒ６＋を還元する。
一方、大気中の酸素と素早く反応する硫酸鉄などは、Ｃｒ６＋の還元能力の持続性がないため、硫黄含有スラグとして好ましくない場合がある。
<Sulfur-containing slag>
As the sulfur-containing slag, for example, it is preferable to use at least one selected from the group consisting of blast furnace slow-cooled slag and desulfurized slag. Cr 0+ is reduced when S 0 , S 2− , S 2 O 3 2− in sulfur-containing slag such as blast furnace slow-cooled slag and desulfurized slag are gradually dissolved in water and oxidized to SO 4 2−. To do.
On the other hand, iron sulfate or the like that reacts quickly with oxygen in the atmosphere is not preferable as a sulfur-containing slag because there is no sustainability of Cr 6+ reduction ability.
硫黄有スラグの硫黄含有量は、＋５価以下の硫黄の合計量が０．１質量％以上であることが好ましい。 The sulfur content of the sulfur-containing slag is preferably such that the total amount of sulfur having a valence of +5 or less is 0.1% by mass or more.
ところで、上述した本発明の還元処理において、クロム酸化物含有物質と混合する「酸化数が＋５価以下の硫黄を含有する物質」として硫黄含有スラグを用いる場合がある。
この場合であっても、本発明の還元処理後にあらためて硫黄含有スラグを配合することに意義がある。本発明の還元処理において水蒸気を吹き込むことにより、硫黄含有スラグ中のＳ０、Ｓ２−、Ｓ２Ｏ３ ２−が洗い流されるか、ガスとして揮発してしまい効力を失うと考えられるからである。
By the way, in the reduction treatment of the present invention described above, sulfur-containing slag may be used as “a substance containing sulfur having an oxidation number of +5 or less” mixed with a chromium oxide-containing substance.
Even in this case, it is meaningful to add sulfur-containing slag again after the reduction treatment of the present invention. This is because by blowing water vapor in the reduction treatment of the present invention, S 0 , S 2− , S 2 O 3 2− in the sulfur-containing slag are washed away or volatilized as a gas, and it is considered that the effectiveness is lost. .
＜硫黄含有スラグの配合量＞
硫黄含有スラグの配合量は、本発明の還元処理が施されたクロム酸化物含有物質１００質量部に対して、５質量部以上である。これにより、クロム酸化物含有物質からのＣｒ６＋の溶出が十分に防止できる。上記配合量の上限は特に限定されないが、例えば、５０質量部以下である。
なお、本発明の還元処理が施されたクロム酸化物含有物質１００質量部に対して、硫黄含有スラグを５０質量部を超えて配合すると、土木工事用材料として特性が向上するような場合には５０質量部を超えて配合しても何ら問題ない。
ここで、「クロム酸化物含有物質１００質量部」には、上述した本発明の還元処理において用いる「酸化数が＋５価以下の硫黄を含有する物質」の質量は含めない。
「クロム酸化物含有物質」および「硫黄含有スラグ」の質量比は、絶乾状態での質量比である。
<Amount of sulfur-containing slag>
The compounding amount of the sulfur-containing slag is 5 parts by mass or more with respect to 100 parts by mass of the chromium oxide-containing material subjected to the reduction treatment of the present invention. Thereby, elution of Cr 6+ from the chromium oxide-containing material can be sufficiently prevented. Although the upper limit of the said compounding quantity is not specifically limited, For example, it is 50 mass parts or less.
In addition, when the sulfur-containing slag exceeds 50 parts by mass with respect to 100 parts by mass of the chromium oxide-containing substance subjected to the reduction treatment of the present invention, the characteristics are improved as a civil engineering material. There is no problem even if it exceeds 50 parts by mass.
Here, the “100 parts by mass of the chromium oxide-containing substance” does not include the mass of the “substance containing sulfur having an oxidation number of +5 or less” used in the reduction treatment of the present invention described above.
The mass ratio of the “chromium oxide-containing substance” and the “sulfur-containing slag” is a mass ratio in the absolutely dry state.
＜土木工事用材料＞
本発明の土木工事用材料の製造方法により得られる土木工事用材料は、特に限定されず、例えば、路盤材、仮設道路材、埋立て材および地盤改良材からなる群から選ばれる少なくとも１種などが挙げられる。
<Materials for civil engineering>
The civil engineering material obtained by the method for producing a civil engineering material of the present invention is not particularly limited, and for example, at least one selected from the group consisting of roadbed material, temporary road material, landfill material, and ground improvement material, etc. Is mentioned.
以下に、実施例を挙げて本発明を具体的に説明する。ただし、本発明はこれらに限定されない。 Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.
＜実施例１〜１４および比較例１〜６＞
実施例１〜１４および比較例１〜６に用いたクロム酸化物含有物質（ステンレス鋼スラグ、コンクリート破砕物および下水汚泥溶融スラグ）の吸水率、環境庁告示第４６号法によるＣｒ６＋溶出量、および、ＪＩＳ Ｋ ００５８−１によるＣｒ６＋溶出量を、下記表１に示す。吸水率は上述した方法により求めた。クロム酸化物含有物質の骨材最大寸法は４０ｍｍであった。ステンレス鋼スラグは、精錬の途中の還元処理工程中に抜き取ったサンプルを使用した。
<Examples 1-14 and Comparative Examples 1-6>
Water absorption of chromium oxide-containing materials (stainless steel slag, concrete crushed material and sewage sludge molten slag) used in Examples 1-14 and Comparative Examples 1-6, Cr 6+ elution amount according to Environment Agency Notification No. 46, Table 1 below shows the amount of Cr 6+ eluted according to JIS K0058-1. The water absorption was determined by the method described above. The maximum aggregate size of the chromium oxide-containing material was 40 mm. As the stainless steel slag, a sample extracted during the reduction process during refining was used.
これらのクロム酸化物含有物質に、下記表２に示す条件で還元処理を施した。
例えば、含水の時期が「混合前」である例である実施例１では、まず、吸水率が６．４質量％であるステンレス鋼スラグに、３．２質量％（吸水率に対して５０％）の工業用水を含ませ、次いで、未エージング高炉徐冷スラグを混合し、得られた混合物に水蒸気の吹き込みを行なった。
一方、含水の時期が「混合後」である例である実施例６では、まず、吸水率が６．４質量％であるステンレス鋼スラグと、未エージング高炉徐冷スラグとを混合し、得られた混合物に、６．８質量％（吸水率に対して１０６％）の工業用水を含ませ、その後、水蒸気の吹き込みを行なった。
その他の実施例２〜５、７〜１４および比較例１〜６も同様に、還元処理を施した。
These chromium oxide-containing materials were subjected to reduction treatment under the conditions shown in Table 2 below.
For example, in Example 1, which is an example in which the water content is “before mixing”, first, 3.2% by mass (50% with respect to the water absorption rate) is added to stainless steel slag having a water absorption rate of 6.4% by mass. ) Industrial water was added, and then unaged blast furnace chilled slag was mixed, and steam was blown into the resulting mixture.
On the other hand, in Example 6, which is an example in which the water content is “after mixing”, first, stainless steel slag having a water absorption rate of 6.4% by mass and unaged blast furnace chilled slag are mixed and obtained. Then, 6.8% by mass (106% with respect to water absorption) of industrial water was added to the mixture, and then steam was blown into the mixture.
Other Examples 2-5, 7-14 and Comparative Examples 1-6 were similarly subjected to reduction treatment.
還元剤（酸化数が＋５価以下の硫黄を含有する物質）としては、未エージング高炉徐冷スラグまたは脱硫スラグを用いた。これらのスラグは、冷却および破砕後１週間以内の試料を用い、骨材最大寸法は２５ｍｍであった。
クロム酸化物含有物質１００質量部に対しては、２０質量部の還元剤を混合した。
混合物の下から１００℃の水蒸気を吹き込み、約１００℃で７２時間保持した後、水蒸気を吹き込むのを止め自然冷却した。
これらは、後述する実施例１５〜２７および比較例７〜８においても同様である。
As a reducing agent (a substance containing sulfur having an oxidation number of +5 or less), non-aging blast furnace slow-cooled slag or desulfurized slag was used. For these slags, samples within one week after cooling and crushing were used, and the maximum aggregate size was 25 mm.
For 100 parts by mass of the chromium oxide-containing substance, 20 parts by mass of a reducing agent was mixed.
Steam at 100 ° C. was blown from the bottom of the mixture, and kept at about 100 ° C. for 72 hours.
The same applies to Examples 15 to 27 and Comparative Examples 7 to 8 described later.
自然冷却後の混合物について、環境庁告示第４６号法およびＪＩＳ Ｋ ００５８−１によるＣｒ６＋溶出量を測定した。その結果を下記表２に併せて示す。 About the mixture after natural cooling, Cr 6+ elution amount by Environmental Agency Notification No. 46 method and JIS K0058-1 was measured. The results are also shown in Table 2 below.
上記表２に示すように、クロム酸化物含有物質の吸水率に対して５０％以上の水を含ませた実施例１〜１４は、いずれも、還元処理後のＣｒ６＋溶出量が、定量下限値である０．０１ｍｇ／Ｌ未満であった。
これに対して、クロム酸化物含有物質の吸水率に対して５０％未満の水を含ませた比較例１〜６は、還元処理後のＣｒ６＋溶出量が０．０２ｍｇ／Ｌ以上であり、クロム酸化物含有物質の還元が不十分であった。
As shown in Table 2 above, Examples 1 to 14 containing 50% or more of water with respect to the water absorption rate of the chromium oxide-containing substance all had a Cr 6+ elution amount after the reduction treatment with a lower limit of quantification. The value was less than 0.01 mg / L.
On the other hand, Comparative Examples 1 to 6 containing water of less than 50% with respect to the water absorption rate of the chromium oxide-containing substance have a Cr 6+ elution amount after the reduction treatment of 0.02 mg / L or more, Reduction of the chromium oxide-containing material was insufficient.
＜実施例１５〜２７および比較例７〜８＞
実施例１５〜２３および比較例７〜８にクロム酸化物含有物質（ステンレス鋼スラグおよびクロム残滓）の吸水率および環境庁告示第４６号法によるＣｒ６＋溶出量を、下記表３に示す。吸水率は上述した方法により求めた。クロム酸化物含有物質の骨材最大寸法は４０ｍｍであった。ステンレス鋼スラグは、精錬の途中の還元処理工程前に抜き取ったサンプルを使用した。Ｃｒ６＋溶出量が比較的多いクロム酸化物含有物質（ステンレス鋼スラグ：１．２ｍｇ／Ｌ、クロム鉱滓：８．５ｍｇ／Ｌ）を用いた。
<Examples 15 to 27 and Comparative Examples 7 to 8>
In Examples 15 to 23 and Comparative Examples 7 to 8, the water absorption of chromium oxide-containing materials (stainless steel slag and chromium residue) and the amount of Cr 6+ eluted by the Environment Agency Notification No. 46 are shown in Table 3 below. The water absorption was determined by the method described above. The maximum aggregate size of the chromium oxide-containing material was 40 mm. As the stainless steel slag, a sample extracted before the reduction treatment step during refining was used. A chromium oxide-containing material (stainless steel slag: 1.2 mg / L, chromium ore: 8.5 mg / L) having a relatively large amount of Cr 6+ elution was used.
これらのクロム酸化物含有物質に、下記表２に示す条件で実施例１〜１４および比較例１〜６と同様にして還元処理を施した後、下記表２に示す硫黄含有スラグを配合して、土木工事用材料を得た。
より詳細には、還元処理を施したクロム酸化物含有物質（約１０トン）に、所定量の３か月間大気エージング後の高炉徐冷スラグまたは脱硫スラグを混合して、得られた土木工事用材料を野外に山積した。
約１年後、山積した土木工事用材料の１００箇所からサンプルを採取し、環境庁告示第４６号法によるＣｒ６＋溶出量を測定し、Ｃｒ６＋溶出量が定量下限値である０．０１ｍｇ／Ｌ以上となった比率を求めた。その結果を下記表４に併せて示す。
These chromium oxide-containing materials were subjected to reduction treatment in the same manner as in Examples 1 to 14 and Comparative Examples 1 to 6 under the conditions shown in Table 2 below, and then compounded with sulfur-containing slag shown in Table 2 below. I got the material for civil engineering work.
More specifically, a reduction-treated chromium oxide-containing material (about 10 tons) is mixed with a predetermined amount of blast furnace chilled slag or desulfurized slag after aging for 3 months for civil engineering work. The material was piled up outdoors.
About 1 year later, samples were collected from 100 places of piled materials for civil engineering work, Cr 6+ elution amount was measured by the Environmental Agency Notification No. 46 method, and Cr 6+ elution amount was 0.01 mg / The ratio which became more than L was calculated | required. The results are also shown in Table 4 below.
上記表４に示すように、クロム酸化物含有物質に、吸水率に対して５０％以上の水を含ませる還元処理を施し、かつ、５質量部以上の硫黄含有スラグを配合した実施例１５〜２３については、１年後のＣｒ６＋溶出量が０．０１ｍｇ／Ｌ以上となった比率が０％であった。 As shown in Table 4 above, Examples 15 to 15 in which the chromium oxide-containing material was subjected to a reduction treatment containing 50% or more of water with respect to the water absorption rate, and 5 parts by mass or more of sulfur-containing slag were blended. For No. 23, the ratio at which the Cr 6+ elution amount after one year became 0.01 mg / L or more was 0%.
したがって、実施例１５〜２３は、同様の還元処理を施したが硫黄含有スラグを配合しなかった実施例２４〜２６、および、同様の還元処理を施したが硫黄含有スラグの配合量が５質量部未満であった実施例２７よりも、Ｃｒ６＋溶出を低減する効果がより優れていた。
なお、上記表４に示すように、クロム酸化物含有物質に、吸水率に対して５０％以上の水を含ませる還元処理を施さないで、５質量部以上の硫黄含有スラグを配合した比較例７〜８は、実施例１５〜２７と比較して、Ｃｒ６＋溶出を低減する効果が不十分であった。
Therefore, in Examples 15 to 23, the same reduction treatment was performed but the sulfur-containing slag was not blended, and the same reduction treatment was performed, but the blending amount of the sulfur-containing slag was 5 mass. The effect of reducing Cr 6+ elution was superior to Example 27, which was less than parts.
In addition, as shown in the said Table 4, the comparative example which mix | blended 5 mass parts or more of sulfur containing slag, without performing the reduction process which contains 50% or more of water with respect to a water absorption rate to a chromium oxide containing material. 7-8 was inadequate in the effect which reduces Cr6 + elution compared with Examples 15-27.
Claims (8)
前記水を含ませた前記クロム酸化物含有物質と、酸化数が＋５価以下の硫黄を含有する物質とを混合し、
前記混合により得られた混合物に水蒸気を吹き込む、クロム酸化物含有物質の還元処理方法。 The chromium oxide-containing material contains 50% or more of water with respect to the water absorption rate of the chromium oxide-containing material,
Mixing the chromium oxide-containing substance containing water and a substance containing sulfur having an oxidation number of +5 or less,
A method for reducing a chromium oxide-containing substance, wherein water vapor is blown into the mixture obtained by the mixing.
前記混合により得られた混合物に、前記クロム酸化物含有物質の吸水率に対して５０％以上の水を含ませ、
前記水を含ませた前記混合物に水蒸気を吹き込む、クロム酸化物含有物質の還元処理方法。 Mixing a chromium oxide-containing substance and a substance containing sulfur with an oxidation number of +5 or less,
The mixture obtained by the mixing contains 50% or more of water with respect to the water absorption rate of the chromium oxide-containing substance,
A method for reducing a chromium oxide-containing material, wherein steam is blown into the mixture containing water.
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