JP5690874B2 - Insolubilizing material and insolubilizing method - Google Patents
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- JP5690874B2 JP5690874B2 JP2013120646A JP2013120646A JP5690874B2 JP 5690874 B2 JP5690874 B2 JP 5690874B2 JP 2013120646 A JP2013120646 A JP 2013120646A JP 2013120646 A JP2013120646 A JP 2013120646A JP 5690874 B2 JP5690874 B2 JP 5690874B2
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- 239000000463 material Substances 0.000 title claims description 66
- 238000000034 method Methods 0.000 title claims description 36
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 103
- 239000000395 magnesium oxide Substances 0.000 claims description 91
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 68
- 239000002893 slag Substances 0.000 claims description 52
- 239000000843 powder Substances 0.000 claims description 37
- 239000000126 substance Substances 0.000 claims description 28
- 238000002156 mixing Methods 0.000 claims description 26
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 11
- 239000011777 magnesium Substances 0.000 claims description 11
- 229910052749 magnesium Inorganic materials 0.000 claims description 11
- 238000005259 measurement Methods 0.000 claims description 9
- 239000004927 clay Substances 0.000 claims description 3
- 229910001385 heavy metal Inorganic materials 0.000 claims description 3
- 239000002689 soil Substances 0.000 description 88
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 description 81
- 238000010828 elution Methods 0.000 description 70
- 235000012245 magnesium oxide Nutrition 0.000 description 70
- 238000012360 testing method Methods 0.000 description 16
- 230000007613 environmental effect Effects 0.000 description 12
- 230000002829 reductive effect Effects 0.000 description 12
- 238000007711 solidification Methods 0.000 description 10
- 230000008023 solidification Effects 0.000 description 10
- 239000000203 mixture Substances 0.000 description 8
- 230000001629 suppression Effects 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 238000010304 firing Methods 0.000 description 7
- 238000002360 preparation method Methods 0.000 description 6
- 239000003440 toxic substance Substances 0.000 description 6
- KSPIHGBHKVISFI-UHFFFAOYSA-N Diphenylcarbazide Chemical compound C=1C=CC=CC=1NNC(=O)NNC1=CC=CC=C1 KSPIHGBHKVISFI-UHFFFAOYSA-N 0.000 description 5
- 238000005056 compaction Methods 0.000 description 5
- 238000011065 in-situ storage Methods 0.000 description 5
- 231100000167 toxic agent Toxicity 0.000 description 5
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 4
- 230000002401 inhibitory effect Effects 0.000 description 4
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 4
- 239000001095 magnesium carbonate Substances 0.000 description 4
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 4
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 4
- 239000000347 magnesium hydroxide Substances 0.000 description 4
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 4
- 238000013008 moisture curing Methods 0.000 description 4
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 239000004567 concrete Substances 0.000 description 3
- 229940031958 magnesium carbonate hydroxide Drugs 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- HZAXFHJVJLSVMW-UHFFFAOYSA-N 2-Aminoethan-1-ol Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 description 2
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 2
- 235000019270 ammonium chloride Nutrition 0.000 description 2
- 239000002956 ash Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000011449 brick Substances 0.000 description 2
- 239000000292 calcium oxide Substances 0.000 description 2
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- FZFYOUJTOSBFPQ-UHFFFAOYSA-M dipotassium;hydroxide Chemical compound [OH-].[K+].[K+] FZFYOUJTOSBFPQ-UHFFFAOYSA-M 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 239000010881 fly ash Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 239000002211 L-ascorbic acid Substances 0.000 description 1
- 235000000069 L-ascorbic acid Nutrition 0.000 description 1
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- GSEJCLTVZPLZKY-UHFFFAOYSA-N Triethanolamine Chemical compound OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- VBIXEXWLHSRNKB-UHFFFAOYSA-N ammonium oxalate Chemical compound [NH4+].[NH4+].[O-]C(=O)C([O-])=O VBIXEXWLHSRNKB-UHFFFAOYSA-N 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
- 229960005070 ascorbic acid Drugs 0.000 description 1
- 239000000872 buffer Substances 0.000 description 1
- 239000006172 buffering agent Substances 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- SXYCCJAPZKHOLS-UHFFFAOYSA-N chembl2008674 Chemical compound [O-][N+](=O)C1=CC=C2C(N=NC3=C4C=CC=CC4=CC=C3O)=C(O)C=C(S(O)(=O)=O)C2=C1 SXYCCJAPZKHOLS-UHFFFAOYSA-N 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000001723 curing Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 229940071106 ethylenediaminetetraacetate Drugs 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 239000000383 hazardous chemical Substances 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 239000002198 insoluble material Substances 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 230000000873 masking effect Effects 0.000 description 1
- 238000010907 mechanical stirring Methods 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 150000002825 nitriles Chemical class 0.000 description 1
- 150000002903 organophosphorus compounds Chemical class 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011669 selenium Substances 0.000 description 1
- 229910052711 selenium Inorganic materials 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Landscapes
- Soil Conditioners And Soil-Stabilizing Materials (AREA)
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
- Processing Of Solid Wastes (AREA)
Description
本発明は、土壌等に含まれる有害物質を不溶化し得る不溶化材に関し、特に6価クロム溶出量の多い土壌等に含まれる6価クロムを不溶化し得る不溶化材に関する。 The present invention relates to an insolubilizing material capable of insolubilizing harmful substances contained in soil or the like, and particularly to an insolubilizing material capable of insolubilizing hexavalent chromium contained in soil or the like having a large amount of hexavalent chromium elution.
近年、工場、事業所、産業廃棄物処理場等の跡地の土壌が、6価クロム等の有害物質で汚染されていることが報告されている。このように、土壌が6価クロム等の有害物質で汚染されると、当該有害物質が溶出し、地下水も汚染されることとなり、人体に影響を及ぼすおそれがあるという安全衛生上の問題のみならず、有害物質による汚染濃度が環境基準値を超えると、跡地をそのまま利用できなくなり、土地の有効利用の妨げとなる。したがって、土壌等に6価クロム等の有害物質が含まれている跡地を有効活用するためにも、土壌等から6価クロム等の有害物質が溶出するのを抑制し、防止するのが望ましいと考えられる。 In recent years, it has been reported that the soils of former sites such as factories, offices, and industrial waste treatment plants are contaminated with harmful substances such as hexavalent chromium. In this way, if the soil is contaminated with harmful substances such as hexavalent chromium, the harmful substances will be eluted and the groundwater will be contaminated. First, if the pollution concentration due to harmful substances exceeds the environmental standard value, the site cannot be used as it is, which hinders effective use of the land. Therefore, it is desirable to suppress and prevent the release of harmful substances such as hexavalent chromium from the soil, etc., in order to effectively utilize the site where harmful substances such as hexavalent chromium are contained in the soil. Conceivable.
従来、6価クロムに汚染された土壌の処理方法として、当該土壌に酸化マグネシウムを添加して、6価クロムの溶出を抑制する方法が提案されている(特許文献1,2参照)。また、6価クロムに汚染された土壌に、酸化カルシウム、酸化マグネシウム及びそれらの前駆物質からなる群から選ばれた少なくとも一種のアルカリ性物質を添加した後に、これを酸素含有率2.5%以下の雰囲気ガスと接触させながら500〜1000℃の範囲内の処理温度で処理し、6価クロムを無害化する方法も提案されている(特許文献3参照)。 Conventionally, as a method for treating soil contaminated with hexavalent chromium, a method for suppressing elution of hexavalent chromium by adding magnesium oxide to the soil has been proposed (see Patent Documents 1 and 2). In addition, after adding at least one alkaline substance selected from the group consisting of calcium oxide, magnesium oxide and their precursors to the soil contaminated with hexavalent chromium, the oxygen content is 2.5% or less. There has also been proposed a method of detoxifying hexavalent chromium by treatment at a treatment temperature within a range of 500 to 1000 ° C. while contacting with atmospheric gas (see Patent Document 3).
しかしながら、上記特許文献1及び2に記載されている方法は、6価クロムによって汚染された土壌に適用して6価クロムの溶出を抑制することは可能であるものの、6価クロム溶出量が多い土壌(例えば、6価クロム溶出量が0.2mg/L以上の土壌)に適用して6価クロムの溶出を効果的に抑制するためには、酸化マグネシウムの添加量を増加させる必要がある。そのため、不溶化処理にかかるコストが高くなってしまうとともに、酸化マグネシウムを混合した後のボリュームが増加するため、副次的な対策が必要であるという問題がある。また、酸化マグネシウムのみを土壌に添加すると、土壌によっては固化強度が実用上十分でないという問題もある。 However, although the methods described in Patent Documents 1 and 2 can be applied to soil contaminated with hexavalent chromium to suppress the elution of hexavalent chromium, the amount of hexavalent chromium elution is large. In order to effectively suppress elution of hexavalent chromium when applied to soil (for example, soil having an elution amount of hexavalent chromium of 0.2 mg / L or more), it is necessary to increase the amount of magnesium oxide added. For this reason, the cost for the insolubilization process is increased, and the volume after mixing with magnesium oxide is increased, so that a secondary measure is required. Moreover, when only magnesium oxide is added to the soil, there is a problem that the solidification strength is not practically sufficient depending on the soil.
さらに、上記特許文献3に記載されている方法は、6価クロムの溶出量が多い土壌(例えば、6価クロム溶出量が0.2mg/L以上の土壌)に適用して6価クロムを不溶化することは可能であるものの、酸素含有率2.5%以下の雰囲気ガスと接触させながら500〜1000℃の範囲で加熱処理する必要があるため、土壌を原位置で処理することができないという問題がある。 Furthermore, the method described in Patent Document 3 is applied to soil having a large amount of hexavalent chromium elution (for example, soil having a hexavalent chromium elution amount of 0.2 mg / L or more) to insolubilize hexavalent chromium. Although it is possible, it is necessary to heat-treat in the range of 500-1000 ° C. while contacting with atmospheric gas having an oxygen content of 2.5% or less, so that the soil cannot be treated in situ. There is.
本発明は、上記課題に鑑みて、6価クロム等の有害物質の溶出量が極めて多い土壌(例えば、6価クロム溶出量が0.7mg/L以上の土壌)等の不溶化処理対象物であっても、当該有害物質を効果的に不溶化することができるとともに、原位置にて不溶化処理を行うことのできる不溶化材及び不溶化方法を提供することを目的とする。 In view of the above-mentioned problems, the present invention is an insolubilization target object such as soil (for example, soil having a hexavalent chromium elution amount of 0.7 mg / L or more) in which an elution amount of harmful substances such as hexavalent chromium is extremely large. However, an object of the present invention is to provide an insolubilizing material and an insolubilizing method that can effectively insolubilize the harmful substance and can perform the insolubilizing treatment in situ.
本発明者らは、上記課題を解決するために鋭意研究した結果、特定の酸化マグネシウム及び高炉スラグ粉末を組み合わせることによって、有害物質の溶出を効果的に抑制し得ることを見出し、本発明を完成した。 As a result of earnest research to solve the above problems, the present inventors have found that by combining specific magnesium oxide and blast furnace slag powder, it is possible to effectively suppress the elution of harmful substances, and the present invention has been completed. did.
すなわち、本発明は、酸化マグネシウムと高炉スラグ粉末とを含有し、有害物質を不溶化し得る不溶化材であって、前記高炉スラグ粉末の配合割合が、前記酸化マグネシウム100質量部に対して5〜900質量部であり、前記不溶化材中の全酸化マグネシウムの質量に対するく溶性苦土(C−MgO)の割合が、85質量%以上であることを特徴とする不溶化材を提供する(発明1)。 That is, the present invention is an insolubilizing material containing magnesium oxide and blast furnace slag powder and capable of insolubilizing harmful substances, wherein the blending ratio of the blast furnace slag powder is 5 to 900 parts by mass with respect to 100 parts by mass of the magnesium oxide. Provided is an insolubilizing material, characterized in that the ratio of soluble magnesia (C-MgO) to the mass of all magnesium oxide in the insolubilizing material is 85 parts by mass or more (Invention 1).
上記発明(発明1)によれば、酸化マグネシウムと、高炉スラグ粉末とを上記範囲内で配合し、く溶性苦土の含有割合を全酸化マグネシウム中85質量%以上とすることで、6価クロム等の有害物質を効果的に不溶化することができ、有害物質溶出量を環境基準値以下に低減することができるとともに、実用上十分な固化強度を発現することができる。また、このような不溶化材は、有害物質を含有する土壌等に添加・混合することで当該有害物質を不溶化することができるため、原位置にて処理することができる。 According to the said invention (invention 1), magnesium oxide and a blast furnace slag powder are mix | blended within the said range, and hexavalent chromium is made into the content rate of a soluble soluble clay to 85 mass% or more in all the magnesium oxides. Can be effectively insolubilized, the amount of toxic substance elution can be reduced below the environmental standard value, and a practically sufficient solidification strength can be exhibited. In addition, such insolubilizing materials can be treated in situ because they can be insolubilized by adding and mixing with soil containing harmful substances.
上記発明(発明1)においては、前記酸化マグネシウムのハンターLab表色系におけるa値が、0.7以上であるのが好ましい(発明2)。かかる発明(発明2)によれば、酸化マグネシウムのハンターLab表色系におけるa値が0.7以上であることで、有害物質の溶出をより効果的に抑制することができる。 In the said invention (invention 1), it is preferable that a value in the Hunter Lab color system of the said magnesium oxide is 0.7 or more (invention 2). According to this invention (invention 2), the a value in the Hunter Lab color system of magnesium oxide is 0.7 or more, whereby elution of harmful substances can be more effectively suppressed.
上記発明(発明1,2)においては、前記酸化マグネシウムが、軽焼マグネシウムであるのが好ましい(発明3)。酸化マグネシウムのうち軽焼マグネシウムは、高炉スラグ粉末と組み合わせることで、優れた有害物質溶出抑制効果を発揮し得るため、かかる発明(発明3)によれば、土壌等に含まれる有害物質をより効果的に不溶化することができる。 In the said invention (invention 1 and 2), it is preferable that the said magnesium oxide is light-burning magnesium (invention 3). Of the magnesium oxides, light burned magnesium can exert an excellent toxic substance elution suppression effect when combined with blast furnace slag powder. Therefore, according to this invention (Invention 3), toxic substances contained in soil and the like are more effective. Can be insolubilized.
なお、本明細書において「軽焼マグネシウム」とは、炭酸マグネシウム又は水酸化マグネシウムを主要原料として、それを650〜1000℃で焼成してなる酸化マグネシウムを意味し、好ましくは750〜1000℃で焼成してなるものであり、より好ましくは800〜1000℃で焼成してなるものである。 In the present specification, “lightly burned magnesium” means magnesium oxide obtained by baking magnesium carbonate or magnesium hydroxide as a main raw material at 650 to 1000 ° C., preferably 750 to 1000 ° C. More preferably, it is obtained by firing at 800 to 1000 ° C.
上記発明(発明1〜3)においては、前記高炉スラグ粉末は、熱質量測定における900〜1000℃での質量増加分が、0.8質量%以下のものであるのが好ましい(発明4)。かかる発明(発明4)によれば、有害物質溶出量の極めて多い土壌(例えば、6価クロム溶出量が0.7mg/L以上の土壌)等であっても、不溶化処理を行うことで有害物質溶出量を環境基準値以下にすることができるため、より優れた有害物質溶出抑制効果を発揮し得るとともに、実用上十分な固化強度を発現することもできる。 In the said invention (invention 1-3), it is preferable that the said blast furnace slag powder is a thing whose mass increase in 900-1000 degreeC in a thermal mass measurement is 0.8 mass% or less (invention 4). According to this invention (invention 4), even if it is soil with a very large amount of toxic substance elution (for example, soil with a hexavalent chromium elution amount of 0.7 mg / L or more), etc. Since the elution amount can be made to be equal to or less than the environmental standard value, it is possible to exhibit a more excellent harmful substance elution suppressing effect and to exhibit practically sufficient solidification strength.
また、本発明は、不溶化処理対象物に含まれる有害物質を不溶化する方法であって、酸化マグネシウムを前記不溶化処理対象物に添加し、混合した後、さらに高炉スラグ粉末を当該不溶化処理対象物に添加し、混合することを特徴とする不溶化方法を提供する(発明5)。 Further, the present invention is a method for insolubilizing harmful substances contained in an insolubilization target, and after adding magnesium oxide to the insolubilization target and mixing, blast furnace slag powder is further added to the insolubilization target. Provided is an insolubilization method characterized by adding and mixing (Invention 5).
上記発明(発明5)によれば、有害物質を含む不溶化処理対象物に酸化マグネシウムを添加・混合し、その後高炉スラグ粉末を不溶化処理対象物に添加・混合することで、酸化マグネシウムと高炉スラグ粉末とを同時に不溶化処理対象物に添加・混合するのに比して、より優れた有害物質溶出抑制効果を発揮することができる。 According to the above invention (Invention 5), magnesium oxide and blast furnace slag powder are added and mixed to the insolubilization target object containing harmful substances, and then the blast furnace slag powder is added to and mixed with the insolubilization target object. In comparison with the simultaneous addition and mixing of the substances to the insolubilized object, it is possible to exhibit a superior toxic substance elution suppression effect.
本明細書において、「不溶化処理対象物」としては、例えば、6価クロム等の有害物質を含む土壌、焼却灰、飛灰、汚泥、レンガやコンクリート等の廃棄物等が挙げられるが、これらに限定されるものではない。 In the present specification, examples of the “insolubilized object” include soil containing harmful substances such as hexavalent chromium, waste such as incineration ash, fly ash, sludge, brick and concrete, etc. It is not limited.
上記発明(発明5)においては、前記酸化マグネシウムの添加量の0.05〜9倍量(質量比)の前記高炉スラグを添加し、前記酸化マグネシウム及び前記高炉スラグ中の酸化マグネシウムの合計質量に対するく溶性苦土(C−MgO)の割合が85質量%以上となるように、前記酸化マグネシウム及び前記高炉スラグを添加するのが好ましい(発明6)。 In the said invention (invention 5), 0.05-9 times amount (mass ratio) of the said blast furnace slag of the addition amount of the said magnesium oxide is added, and it is with respect to the total mass of the magnesium oxide and the magnesium oxide in the said blast furnace slag. It is preferable to add the magnesium oxide and the blast furnace slag so that the ratio of highly soluble mould (C-MgO) is 85% by mass or more (Invention 6).
上記発明(発明6)によれば、有害物質の溶出をより効果的に抑制し得るとともに、実用上十分な固化強度を発現することができる。 According to the said invention (invention 6), the elution of a hazardous | toxic substance can be suppressed more effectively, and practically sufficient solidification intensity | strength can be expressed.
本発明の不溶化材及び不溶化方法によれば、6価クロム等の有害物質の溶出量が極めて多い土壌(例えば、6価クロム溶出量が0.7mg/L以上の土壌)等の不溶化処理対象物であっても当該有害物質を効果的に不溶化することができるとともに、原位置にて不溶化処理を行うことができる。 According to the insolubilizing material and the insolubilizing method of the present invention, the insolubilization target object such as soil (for example, soil in which hexavalent chromium elution amount is 0.7 mg / L or more) with a very large amount of elution of harmful substances such as hexavalent chromium. Even so, the harmful substance can be effectively insolubilized and insolubilized at the original position.
以下、本発明の一実施形態に係る不溶化材について詳細に説明する。なお、本実施形態に係る不溶化材が不溶化し得る有害物質として、土壌中の6価クロムを例に挙げて説明するが、本発明の不溶化材が不溶化し得る物質はこれに限定されるものではなく、例えば、マンガン、銅、カドミウム、水銀、鉛、亜鉛、砒素、セレン等の重金属、シアン化合物、フッ素、有機リン化合物、又はこれらの混合物等も含むものである。 Hereinafter, the insolubilizing material according to an embodiment of the present invention will be described in detail. In addition, although the insoluble material according to the present embodiment will be described as an example of a hazardous substance that can be insolubilized by using hexavalent chromium in soil, the material that can be insolubilized by the insolubilized material of the present invention is not limited to this. For example, it includes heavy metals such as manganese, copper, cadmium, mercury, lead, zinc, arsenic, selenium, cyanide compounds, fluorine, organic phosphorus compounds, or mixtures thereof.
本実施形態に係る不溶化材は、酸化マグネシウムと高炉スラグとを含有する。酸化マグネシウムとしては、天然に産出されるものであってもよいし、工業的に製造されるものであってもよい。工業的に製造される酸化マグネシウムとしては、例えば、炭酸マグネシウム又は水酸化マグネシウムを主要原料として、それを所定の温度で焼成して得られるもの等が挙げられる。 The insolubilizing material according to the present embodiment contains magnesium oxide and blast furnace slag. Magnesium oxide may be naturally produced or industrially produced. Examples of the magnesium oxide produced industrially include those obtained by baking magnesium carbonate or magnesium hydroxide as a main raw material at a predetermined temperature.
本実施形態における酸化マグネシウムは、上記のようにして焼成して工業的に製造される酸化マグネシウムのうち、軽焼マグネシウムであるのが好ましい。かかる軽焼マグネシウムは、650〜1000℃で焼成して得られるものであるのが好ましく、750〜1000℃で焼成して得られるものであるのがより好ましく、800〜1000℃で焼成して得られるものであるのが特に好ましい。上記温度範囲で焼成して得られる軽焼マグネシウムであれば、土壌中の6価クロムの溶出を効果的に抑制し得るとともに、実用上十分な固化強度を発現することができる。 The magnesium oxide in the present embodiment is preferably light-burned magnesium among magnesium oxides that are baked and industrially produced as described above. Such light burned magnesium is preferably obtained by firing at 650 to 1000 ° C, more preferably obtained by firing at 750 to 1000 ° C, and obtained by firing at 800 to 1000 ° C. It is particularly preferred that If it is light calcined magnesium obtained by calcining in the above temperature range, elution of hexavalent chromium in the soil can be effectively suppressed, and practically sufficient solidification strength can be expressed.
なお、酸化マグネシウムの焼成原料である炭酸マグネシウム又は水酸化マグネシウムとしては、6価クロムの溶出抑制効果の観点から、不純物含有量の少ないものを使用するのが好ましい。具体的には、焼成後の酸化マグネシウム量が85質量%以上となるものを使用するのが好ましく、90質量%以上となるものがより好ましい。 In addition, as magnesium carbonate or magnesium hydroxide which is a firing raw material of magnesium oxide, it is preferable to use one having a small impurity content from the viewpoint of the effect of suppressing elution of hexavalent chromium. Specifically, it is preferable to use a magnesium oxide amount after firing of 85% by mass or more, and more preferably 90% by mass or more.
酸化マグネシウムのブレーン比表面積は、3000〜10000cm2/gであるのが好ましく、3500〜9000cm2/gであるのがより好ましい。酸化マグネシウムのブレーン比表面積が3000cm2/g未満であると、6価クロムの溶出抑制効果が低減するとともに、実用上十分な固化強度を発現することも困難となるおそれがある。また、酸化マグネシウムのブレーン比表面積が10000cm2/gを超えるものは、入手が困難である上、サイロ等での保管に至ってはシュート詰まり等のトラブルを引き起こすおそれがあり、またコストも高くなるおそれがある。 Blaine specific surface area of magnesium oxide is preferably from 3000~10000cm 2 / g, and more preferably 3500~9000cm 2 / g. If the Blaine specific surface area of magnesium oxide is less than 3000 cm 2 / g, the elution suppression effect of hexavalent chromium may be reduced, and it may be difficult to achieve practically sufficient solidification strength. Further, magnesium oxide having a brane specific surface area exceeding 10,000 cm 2 / g is difficult to obtain and may cause troubles such as clogging of shoots when stored in a silo or the like, and the cost may increase. There is.
酸化マグネシウムの密度は、3.0〜3.6g/cm3であるのが好ましく、3.3〜3.6g/cm3であるのがより好ましい。上記密度の範囲を有する酸化マグネシウムは、風化によって受けた劣化が小さいことから水和活性度が高く、6価クロムの溶出抑制効果に優れる上、固化強度の発現においても優れる。 The density of the magnesium oxide is preferably from 3.0~3.6g / cm 3, and more preferably 3.3~3.6g / cm 3. Magnesium oxide having the above density range has high hydration activity due to small deterioration caused by weathering, and is excellent in the effect of inhibiting elution of hexavalent chromium, and is also excellent in the expression of solidification strength.
また、本実施形態における酸化マグネシウムは、不溶化材に配合した場合に、不溶化材中の全酸化マグネシウム量に対するく溶性苦土(C−MgO)の割合が、85質量%以上となるものが好ましく、87質量%以上となるものがより好ましく、90質量%以上となるものが特に好ましい。当該く溶性苦土の割合が85質量%未満であると、6価クロム溶出量の多い土壌(6価クロム溶出量が0.2mg/L以上の土壌)の不溶化処理に用いた際に、6価クロム溶出抑制効果が低減するおそれがある。 Moreover, when the magnesium oxide in this embodiment is mix | blended with the insolubilization material, the thing in which the ratio of the soluble magnesia (C-MgO) with respect to the total magnesium oxide amount in an insolubilization material becomes 85 mass% or more, What becomes 87 mass% or more is more preferable, and what becomes 90 mass% or more is particularly preferable. When the ratio of the soluble soluble clay is less than 85% by mass, when used for insolubilization of soil with a large amount of hexavalent chromium elution (soil with a hexavalent chromium elution amount of 0.2 mg / L or more), There is a possibility that the effect of suppressing the valence chromium elution is reduced.
なお、不溶化材中の全酸化マグネシウム量に対するく溶性苦土(C−MgO)の含有割合を測定する方法としては、特に限定されるものではなく常法に従って行うことができる。 In addition, it does not specifically limit as a method of measuring the content rate of the soluble magnesia (C-MgO) with respect to the total magnesium oxide amount in an insolubilization material, It can carry out in accordance with a conventional method.
例えば、試料としての不溶化材の粒度を200メッシュ全通に調整し、試料に2%クエン酸を加え30℃で1時間回転振とうする(30〜40rpm)。振とう後、冷却して緩衝材(塩化アンモニウム、モノエタノールアミン等)を添加し、希塩酸及び希アンモニア水にてpH5程度の弱酸性に調整する。その後、シュウ酸アンモニウムを添加し、80℃の湯浴にて1時間反応させる。 For example, the particle size of the insolubilizing material as a sample is adjusted to 200 mesh, 2% citric acid is added to the sample, and the mixture is shaken at 30 ° C. for 1 hour (30 to 40 rpm). After shaking, cool and add a buffer material (ammonium chloride, monoethanolamine, etc.), and adjust to weak acidity of about pH 5 with dilute hydrochloric acid and dilute aqueous ammonia. Thereafter, ammonium oxalate is added and reacted in a hot water bath at 80 ° C. for 1 hour.
マスキング剤としてのL−アスコルビン酸、(1+3)トリエタノールアミン、KCN等を添加するとともに、緩衝剤としてモノエタノールアミン又は塩化アンモニウム(pH10.6)を添加して溶液のpHを10付近に調整する。 Add L-ascorbic acid, (1 + 3) triethanolamine, KCN, etc. as a masking agent, and adjust the pH of the solution to around 10 by adding monoethanolamine or ammonium chloride (pH 10.6) as a buffering agent. .
そして、指示薬としてエリオクロムブラックT数滴を加え、標準エチレンジアミン四酢酸塩液で滴定することで、く溶性苦土(C−MgO)の含有割合(質量%)を測定する。 Then, a few drops of Eriochrome Black T are added as an indicator, and the content (mass%) of soluble soluble earth (C-MgO) is measured by titration with a standard ethylenediaminetetraacetate solution.
本実施形態における酸化マグネシウムは、ハンターLab表色系におけるa値が0.7以上であるのが好ましく、0.9以上であるのがより好ましい。当該a値が0.7未満であると、6価クロム溶出量の多い土壌(6価クロム溶出量が0.2mg/L以上の土壌)に対する6価クロムの溶出抑制効果が低減するおそれがある。なお、当該a値は、分光色差計(日本電色社製,商品名:CP6R−2000DP)を用いて測定することができる。 The magnesium oxide in this embodiment preferably has an a value in the Hunter Lab color system of 0.7 or more, more preferably 0.9 or more. If the a value is less than 0.7, the hexavalent chromium elution inhibitory effect on soil with a large amount of hexavalent chromium elution (soil with hexavalent chromium elution amount of 0.2 mg / L or more) may be reduced. . The a value can be measured using a spectral color difference meter (manufactured by Nippon Denshoku Co., Ltd., trade name: CP6R-2000DP).
本実施形態における高炉スラグ粉末は、そのブレーン比表面積が3000〜10000cm2/gであるのが好ましく、4000〜9000cm2/gであるのがより好ましい。高炉スラグ粉末のブレーン比表面積が3000cm2/g未満であると、6価クロムの溶出抑制効果が低減するとともに、実用上十分な固化強度を発現することも困難となるおそれがある。また、高炉スラグ粉末のブレーン比表面積が10000cm2/gを超えるものは、入手が困難である上、サイロ等で保管する場合にシュート詰まり等のトラブルを引き起こすおそれがあり、コストも高くなるおそれがある。 Blast furnace slag powder in the present embodiment, the Blaine specific surface area is preferably from 3000~10000cm 2 / g, and more preferably 4000~9000cm 2 / g. If the Blaine specific surface area of the blast furnace slag powder is less than 3000 cm 2 / g, the effect of suppressing the elution of hexavalent chromium may be reduced, and it may be difficult to achieve practically sufficient solidification strength. In addition, when the blast furnace slag powder has a Blaine specific surface area exceeding 10,000 cm 2 / g, it is difficult to obtain and may cause troubles such as shoot clogging when stored in a silo, which may increase the cost. is there.
また、本実施形態における高炉スラグ粉末は、熱質量測定における900〜1000℃での質量増加分が0.8質量%以下であるのが好ましく、0.75質量%以下であるのがより好ましい。かかる質量増加分が0.8質量%以下であれば、6価クロム溶出量が極めて多い土壌(6価クロム溶出量が0.7mg/L以上の土壌)に対しても優れた6価クロム溶出抑制効果を発揮し得る。 In the blast furnace slag powder in the present embodiment, the mass increase at 900 to 1000 ° C. in thermal mass measurement is preferably 0.8% by mass or less, and more preferably 0.75% by mass or less. If the mass increase is 0.8% by mass or less, the hexavalent chromium elution is excellent even for soil with a large amount of hexavalent chromium elution (soil having a hexavalent chromium elution amount of 0.7 mg / L or more). An inhibitory effect can be exhibited.
なお、高炉スラグ粉末の熱質量測定は、慣用の熱質量測定装置を用いて行うことができ、その測定条件は、サンプル量が30〜80mgであり、昇温速度が20℃/minで1000℃まで昇温し、大気雰囲気下で行うことができる。 In addition, the thermal mass measurement of blast furnace slag powder can be performed using a conventional thermal mass measuring apparatus, and the measurement conditions are a sample amount of 30 to 80 mg, a temperature increase rate of 20 ° C./min and 1000 ° C. The temperature can be increased up to atmospheric temperature.
さらに、本実施形態における高炉スラグ粉末の酸化カリウム(K2O)含有量は、0.35質量%以下であるのが好ましく、0.3質量%以下であるのがより好ましい。高炉スラグ粉末の酸化カリウム(K2O)含有量が0.35質量%以下であれば、6価クロム溶出量の極めて多い土壌(6価クロム溶出量が0.7mg/L以上の土壌)に対しても優れた6価クロム溶出抑制効果を発揮し得る。 Furthermore, the potassium oxide (K 2 O) content of the blast furnace slag powder in this embodiment is preferably 0.35% by mass or less, and more preferably 0.3% by mass or less. If the content of potassium oxide (K 2 O) in the blast furnace slag powder is 0.35% by mass or less, the amount of hexavalent chromium elution amount is extremely large (soil in which hexavalent chromium elution amount is 0.7 mg / L or more). Also, an excellent hexavalent chromium elution suppression effect can be exhibited.
本実施形態に係る不溶化材は、酸化マグネシウム及び高炉スラグ粉末のみからなるものであってもよいし、酸化マグネシウム及び高炉スラグ粉末以外の他の成分を含むものであってもよい。上記不溶化材が酸化マグネシウム及び高炉スラグ粉末以外の他の成分を含むものである場合、酸化マグネシウム及び高炉スラグ粉末が主成分として含まれているのが好ましく、具体的には、酸化マグネシウムと高炉スラグ粉末との合計量が、不溶化材全体量に対して90質量%以上であるのが好ましい。 The insolubilizing material according to the present embodiment may be composed only of magnesium oxide and blast furnace slag powder, or may contain other components other than magnesium oxide and blast furnace slag powder. When the insolubilizing material contains other components than magnesium oxide and blast furnace slag powder, it is preferable that magnesium oxide and blast furnace slag powder are contained as main components, specifically, magnesium oxide and blast furnace slag powder. Is preferably 90% by mass or more based on the total amount of the insolubilized material.
不溶化材が、酸化マグネシウム及び高炉スラグ粉末を主成分として含むものである場合、当該不溶化材に含まれる他の成分としては、例えば、酸化マグネシウムの焼成原料である炭酸マグネシウム又は水酸化マグネシウムに含まれているSiO2、Al2O3、Fe2O3、CaO等が挙げられるが、不溶化材が有する6価クロム溶出抑制効果を妨げるものでない限り、これらに限定されるものではない。 When the insolubilized material contains magnesium oxide and blast furnace slag powder as main components, the other components included in the insolubilized material include, for example, magnesium carbonate or magnesium hydroxide, which is a firing material of magnesium oxide. Examples thereof include SiO 2 , Al 2 O 3 , Fe 2 O 3 , and CaO, but are not limited to these as long as they do not interfere with the hexavalent chromium elution suppressing effect of the insolubilizing material.
本実施形態に係る不溶化材中の酸化マグネシウムと高炉スラグ粉末との配合割合は、酸化マグネシウム100質量部に対して、高炉スラグ5〜900質量部であり、フッ素等の他の汚染物質も含む複合汚染土壌に使用する場合を考慮すると、10〜100質量部であるのが好ましく、15〜70質量部であるのがより好ましい。 The compounding ratio of magnesium oxide and blast furnace slag powder in the insolubilized material according to this embodiment is 5 to 900 parts by mass of blast furnace slag with respect to 100 parts by mass of magnesium oxide, and is a composite containing other contaminants such as fluorine. Considering the case of using for contaminated soil, it is preferably 10 to 100 parts by mass, more preferably 15 to 70 parts by mass.
酸化マグネシウム100質量部に対する高炉スラグ粉末の配合割合が5質量部未満であると、6価クロム溶出量の多い土壌(6価クロム溶出量が0.2mg/L以上の土壌)に適用する場合に、6価クロムの溶出を抑制するために添加量が増大するおそれがあり、不溶化処理にかかるコストが高くなるとともに、不溶化材を土壌に混合した後のボリュームが増加し、副次的な対策が必要となるおそれがある。一方、高炉スラグ粉末の配合割合が900質量部を超えると、実用上十分な固化強度を発現するのに相当な時間がかかってしまうおそれがある。 When the blending ratio of the blast furnace slag powder with respect to 100 parts by mass of magnesium oxide is less than 5 parts by mass, it is applied to soil having a large amount of hexavalent chromium elution (soil having a hexavalent chromium elution amount of 0.2 mg / L or more). There is a possibility that the amount added will increase in order to suppress the elution of hexavalent chromium, and the cost for insolubilization will increase, and the volume after mixing the insolubilizing material with the soil will increase, so that secondary measures will be taken. May be necessary. On the other hand, when the blending ratio of the blast furnace slag powder exceeds 900 parts by mass, it may take a considerable time to develop a practically sufficient solidification strength.
本実施形態に係る不溶化材を用いて土壌中の6価クロムを不溶化する方法としては、6価クロムを含有する土壌に、粉体状又はスラリー状に調製した不溶化材を添加し、当該土壌を混合する方法が挙げられる。不溶化材の添加の簡便性を重視すれば、粉体状の不溶化材を添加するのが好ましく、不溶化処理における粉塵の発生の抑制や不溶化材と土壌との混合性を考慮すれば、スラリー状の不溶化材を添加するのが好ましい。なお、スラリー状の不溶化材を添加する場合、当該スラリーの水粉体比は、100〜400質量%であるのが好ましい。 As a method for insolubilizing hexavalent chromium in soil using the insolubilizing material according to the present embodiment, an insolubilizing material prepared in powder or slurry form is added to the soil containing hexavalent chromium, and the soil is The method of mixing is mentioned. If importance is attached to the ease of addition of the insolubilizing material, it is preferable to add the powdered insolubilizing material, and considering the suppression of dust generation in the insolubilization treatment and the mixing of the insolubilizing material with the soil, It is preferable to add an insolubilizing material. In addition, when adding a slurry-like insolubilizing material, it is preferable that the water powder ratio of the said slurry is 100-400 mass%.
不溶化材を土壌に添加する場合、酸化マグネシウム及び高炉スラグ粉末をあらかじめ混合してなる不溶化材を添加してもよいし、酸化マグネシウムと高炉スラグとを別々に添加してもよい。 When the insolubilizing material is added to the soil, an insolubilizing material obtained by previously mixing magnesium oxide and blast furnace slag powder may be added, or magnesium oxide and blast furnace slag may be added separately.
酸化マグネシウムと高炉スラグ粉末とを別々に添加する場合には、まず、酸化マグネシウムを土壌に添加・混合し、所定の時間(例えば1〜60分程度)経過後に、高炉スラグ粉末を土壌に添加・混合するのが好ましい。これにより、6価クロムの溶出をより効果的に抑制することができる。 When adding magnesium oxide and blast furnace slag powder separately, first add and mix magnesium oxide to the soil. After a predetermined time (for example, about 1 to 60 minutes), add the blast furnace slag powder to the soil. It is preferable to mix. Thereby, elution of hexavalent chromium can be suppressed more effectively.
本実施形態に係る不溶化材と土壌との混合処理としては、土壌の改良深さによって異なるが、改良深さが2〜3m程度であればスタビライザや特殊バックホウ等の混合機械を用いた原位置混合方式又はプラントで連続的に混合する事前混合方式等を採用することができる。 As the mixing treatment of the insolubilizing material and the soil according to the present embodiment, although depending on the soil improvement depth, if the improvement depth is about 2 to 3 m, in-situ mixing using a mixing machine such as a stabilizer or a special backhoe A premixing method or the like that continuously mixes in a method or a plant can be adopted.
一方、改良深さが3mを超える場合には、機械攪拌翼方式若しくは噴射攪拌方式を用いる深層混合処理工法、又は柱列式若しくは等厚壁式を用いるソイルセメント地中連続壁工法等を採用することができる。 On the other hand, when the improved depth exceeds 3 m, a deep mixing process method using a mechanical stirring blade method or a jet stirring method, or a soil cement underground continuous wall method using a columnar method or a constant wall method is adopted. be able to.
本実施形態に係る不溶化材を土壌に添加する場合、土壌への不溶化材の添加量は、不溶化処理対象土壌1m3あたり50〜300kgであるのが好ましく、100〜250kgであるのがより好ましい。不溶化材の添加量が50kg未満であると、土壌に含まれる有害物質を効果的に不溶化することができず、有害物質の溶出を効果的に抑制することができないおそれがあり、300kgを超えると、不溶化処理にかかるコストが高くなるおそれがあるとともに、不溶化材を混合した後のボリュームが増加するため、副次的な対策が必要となるおそれがある。 When the insolubilizing material according to the present embodiment is added to the soil, the amount of the insolubilizing material added to the soil is preferably 50 to 300 kg, more preferably 100 to 250 kg per 1 m 3 of the insolubilizing treatment target soil. If the added amount of the insolubilizing material is less than 50 kg, harmful substances contained in the soil cannot be effectively insolubilized, and the elution of harmful substances may not be effectively suppressed. The cost for the insolubilization process may increase, and the volume after mixing the insolubilizing material increases, so that a secondary measure may be required.
以上説明したように、本実施形態に係る不溶化材は、上記のような特定の酸化マグネシウムと高炉スラグ粉末とを組み合わせることで、6価クロム溶出量の多い土壌(6価クロム溶出量が0.2mg/L以上の土壌)に適用した場合であっても、土壌に含まれる6価クロムの溶出を効果的に抑制することができるとともに、原位置での不溶化処理を行うことができる。また、かかる不溶化材を用いることで、土壌に含まれる6価クロムの不溶化処理を短時間で行うことができる。 As described above, the insolubilizing material according to the present embodiment combines soil with a specific magnesium oxide and blast furnace slag powder as described above, so that the amount of hexavalent chromium elution is large (the amount of hexavalent chromium elution is 0.1. Even when applied to soil of 2 mg / L or more, elution of hexavalent chromium contained in the soil can be effectively suppressed, and insolubilization treatment in situ can be performed. Moreover, the insolubilization process of the hexavalent chromium contained in soil can be performed in a short time by using this insolubilizing material.
以上説明した実施形態は、本発明の理解を容易にするために記載されたものであって、本発明を限定するために記載されたものではない。したがって、上記実施形態に開示された各要素は、本発明の技術的範囲に属する全ての設計変更や均等物をも含む趣旨である。 The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.
例えば、上記実施形態に係る不溶化材は、土壌に含まれる6価クロムの不溶化処理に用いられるものとして説明したが、これに限定されるものではなく、例えば、焼却灰、飛灰、汚泥、レンガやコンクリート等の廃棄物等に含まれる6価クロム等の有害物質の不溶化処理に用いることもできる。 For example, although the insolubilization material which concerns on the said embodiment was demonstrated as what is used for the insolubilization process of the hexavalent chromium contained in soil, it is not limited to this, For example, incineration ash, fly ash, sludge, brick It can also be used to insolubilize harmful substances such as hexavalent chromium contained in wastes such as concrete and concrete.
以下、実施例及び試験例を示し、本発明をより詳細に説明するが、本発明は下記の実施例及び試験例に何ら限定されるものではない。なお、下記の実施例及び試験例においては、酸化マグネシウム及び高炉スラグとして、下記表1及び2に示す材料を使用した。 EXAMPLES Hereinafter, although an Example and a test example are shown and this invention is demonstrated in detail, this invention is not limited to the following Example and test example at all. In the following Examples and Test Examples, materials shown in Tables 1 and 2 below were used as magnesium oxide and blast furnace slag.
〔試験例〕模擬汚染土壌からの6価クロム溶出抑制効果確認試験1〜5
(1)模擬汚染土壌の調製
粘性土(含水比:22%,湿潤密度:1.953)に二クロム酸カリウム(K2Cr2O7,試薬特級)を添加・混合した後、24時間静置して下記表3に示す模擬汚染土壌1〜4を調製した。
[Test Example] Hexavalent chromium elution suppression confirmation test 1-5 from simulated contaminated soil
(1) Preparation of simulated contaminated soil Potassium dichromate (K 2 Cr 2 O 7 , reagent special grade) was added to and mixed with viscous soil (water content: 22%, wet density: 1.953), and then allowed to stand for 24 hours. The simulated contaminated soils 1 to 4 shown in Table 3 below were prepared.
(2)試験1
模擬汚染土壌1に、下記表4に示す配合の不溶化材(実施例1〜2,比較例1)を100kg/m3となるように添加し、ホバートミキサで3分間混合して、JGS−0821「安定処理土の締固めをしない供試体作製」に準じて直径3.5cm×高さ7cmの供試体を作製した。
(2) Test 1
Insolubilized materials (Examples 1 and 2 and Comparative Example 1) having the composition shown in Table 4 below were added to the simulated contaminated soil 1 so as to be 100 kg / m 3 , mixed for 3 minutes with a Hobart mixer, and JGS-0821 A specimen having a diameter of 3.5 cm and a height of 7 cm was produced according to “Preparation of specimen without compaction of stabilized soil”.
得られた供試体を20℃にて7日間湿空養生を行った後、6価クロムの溶出量を環境庁告示第46号法に準じて、ジフェニルカルバジド吸光光度法で測定した。結果を表4に示す。なお、表4中「C−MgO/全MgO」は、不溶化材中の全MgOに対するく溶性苦土(C−MgO)の質量比を表すものである。 The obtained specimen was subjected to moisture curing at 20 ° C. for 7 days, and then the elution amount of hexavalent chromium was measured by diphenylcarbazide absorptiometry according to the Environmental Agency Notification No.46 method. The results are shown in Table 4. In Table 4, “C—MgO / total MgO” represents the mass ratio of soluble magnesia (C—MgO) to total MgO in the insolubilized material.
表4に示すように、実施例1及び2の不溶化材は、6価クロムの溶出量の多い模擬汚染土壌1からの6価クロムの溶出量を土壌に対する環境基準値(0.05mg/L)以下に低減可能であることが確認された。このことから、不溶化材中のく溶性苦土(C−MgO)含有率が85質量%以上であれば、6価クロムの溶出量を効果的に低減することができることが判明した。 As shown in Table 4, the insolubilized materials of Examples 1 and 2 are the environmental standard value (0.05 mg / L) for the amount of elution of hexavalent chromium from simulated contaminated soil 1 with a large amount of elution of hexavalent chromium. It was confirmed that the following can be reduced. From this, it was found that if the content of soluble magnesia (C-MgO) in the insolubilized material is 85 mass% or more, the elution amount of hexavalent chromium can be effectively reduced.
(3)試験2
模擬汚染土壌2及び模擬汚染土壌3のそれぞれに、表5に示す配合の不溶化材(実施例3〜8)を100kg/m3となるように添加し、ホバートミキサで3分間混合して、JGS−0821「安定処理土の締固めをしない供試体作製」に準じて直径3.5cm×高さ7cmの供試体を作製した。
(3) Test 2
To each of the simulated contaminated soil 2 and the simulated contaminated soil 3, an insolubilizing material (Examples 3 to 8) having the composition shown in Table 5 was added to 100 kg / m 3 and mixed for 3 minutes with a Hobart mixer. A specimen having a diameter of 3.5 cm and a height of 7 cm was prepared in accordance with −0821 “Preparation of specimen without compaction of stabilized soil”.
得られた供試体を20℃にて7日間湿空養生を行った後、6価クロムの溶出量を環境庁告示第46号法に準じて、ジフェニルカルバジド吸光光度法で測定した。結果を表5に示す。なお、表5中「C−MgO/全MgO」は、不溶化材中の全MgOに対するく溶性苦土(C−MgO)の質量比を表すものである。 The obtained specimen was subjected to moisture curing at 20 ° C. for 7 days, and then the elution amount of hexavalent chromium was measured by diphenylcarbazide absorptiometry according to the Environmental Agency Notification No.46 method. The results are shown in Table 5. In Table 5, “C—MgO / total MgO” represents the mass ratio of soluble mould (C—MgO) to total MgO in the insolubilized material.
表5に示すように、実施例3〜8の不溶化材は、6価クロム溶出量の多い模擬汚染土壌2からの6価クロム溶出量を土壌に対する環境基準値(0.05mg/L)以下に低減可能であることが確認された。 As shown in Table 5, the insolubilized materials of Examples 3 to 8 have the hexavalent chromium elution amount from the simulated contaminated soil 2 having a large hexavalent chromium elution amount below the environmental standard value (0.05 mg / L) for the soil. It was confirmed that it could be reduced.
また、熱質量測定における900〜1000℃での質量増加分が0.8質量%以下の高炉スラグ粉末を含有する、実施例3〜6の不溶化材は、6価クロム溶出量の極めて多い模擬汚染土壌3からの6価クロム溶出量を土壌に対する環境基準値(0.05mg/L)以下に低減可能であることが確認された。このことから、熱質量測定における900〜1000℃での質量増加分が0.8質量%以下の高炉スラグ粉末を不溶化材に含有せしめることで、特に優れた6価クロム溶出抑制効果を発揮し得ることが明らかとなった。 Moreover, the insolubilization material of Examples 3-6 containing the blast furnace slag powder whose mass increase in 900-1000 degreeC in a thermal mass measurement is 0.8 mass% or less is simulated contamination with very much hexavalent chromium elution amount. It was confirmed that the hexavalent chromium elution amount from the soil 3 can be reduced to an environmental standard value (0.05 mg / L) or less for the soil. From this fact, a particularly excellent hexavalent chromium elution suppression effect can be exhibited by including in the insolubilizing material a blast furnace slag powder whose mass increase at 900 to 1000 ° C. in thermal mass measurement is 0.8% by mass or less. It became clear.
(4)試験3
模擬汚染土壌4に、表6に示す配合の不溶化材(実施例3,9,10,比較例2)を表6に示す量となるように添加し、ホバートミキサで3分間混合して、JGS−0821「安定処理土の締固めをしない供試体作製」に準じて直径3.5cm×高さ7cmの供試体を作製した。
(4) Test 3
To the simulated contaminated soil 4, an insolubilizing material having the composition shown in Table 6 (Examples 3, 9, 10 and Comparative Example 2) was added so as to have the amount shown in Table 6, and mixed for 3 minutes with a Hobart mixer. A specimen having a diameter of 3.5 cm and a height of 7 cm was prepared in accordance with −0821 “Preparation of specimen without compaction of stabilized soil”.
得られた供試体を20℃にて7日間及び28日間湿空養生を行った後、6価クロムの溶出量を環境庁告示第46号法に準じて、ジフェニルカルバジド吸光光度法で測定した。また、当該供試体について、一軸圧縮強さを測定した。結果を表6に示す。なお、表6中「C−MgO/全MgO」は、不溶化材中の全MgOに対するく溶性苦土(C−MgO)の質量比を表すものである。 After subjecting the obtained specimens to wet curing at 20 ° C. for 7 days and 28 days, the elution amount of hexavalent chromium was measured by diphenylcarbazide absorptiometry according to the Environmental Agency Notification No. 46 method. . Moreover, the uniaxial compressive strength was measured about the said test piece. The results are shown in Table 6. In Table 6, “C—MgO / total MgO” represents the mass ratio of soluble mould (C—MgO) to total MgO in the insolubilized material.
表6に示すように、実施例3,9及び10の不溶化材は、6価クロムの溶出量の多い模擬汚染土壌4からの6価クロムの溶出量を土壌に対する環境基準値(0.05mg/L)以下に低減可能であることが確認された。また、実施例3,9及び10の不溶化材は、実用上十分な固化強度を発現可能であることも確認された。 As shown in Table 6, the insolubilized materials of Examples 3, 9 and 10 were obtained by setting the elution amount of hexavalent chromium from the simulated contaminated soil 4 having a large elution amount of hexavalent chromium to the environmental standard value (0.05 mg / kg). L) It was confirmed that the following can be reduced. It was also confirmed that the insolubilized materials of Examples 3, 9 and 10 can exhibit practically sufficient solidification strength.
(5)試験4
模擬汚染土壌1に、軽焼マグネシウム1を71.5kg/m3(100質量部)となるように添加してホバートミキサで1.5分間混合した後、さらに高炉スラグ2を28.5kg/m3(40質量部)となるように添加してホバートミキサで1.5分間混合した(実施例11)。なお、本試験4における軽焼マグネシウム1と高炉スラグ2との添加割合は、上記表4に示す実施例1の配合割合と同一になるようにした。その後、JGS−0821「安定処理土の締固めをしない供試体作製」に準じて直径3.5cm×高さ7cmの供試体を作製した。
(5) Test 4
After adding light burned magnesium 1 to the simulated contaminated soil 1 to 71.5 kg / m 3 (100 parts by mass) and mixing for 1.5 minutes with a Hobart mixer, 28.5 kg / m of blast furnace slag 2 was further added. 3 (40 parts by mass) and mixed for 1.5 minutes by a Hobart mixer (Example 11). In addition, the addition ratio of the light burned magnesium 1 and the blast furnace slag 2 in the test 4 was set to be the same as the mixing ratio of Example 1 shown in Table 4 above. Thereafter, a specimen having a diameter of 3.5 cm and a height of 7 cm was prepared according to JGS-0821 “Preparation of specimen without compaction of stabilized soil”.
得られた供試体を20℃にて7日間湿空養生を行った後、6価クロムの溶出量を環境庁告示第46号法に準じて、ジフェニルカルバジド吸光光度法で測定した。かかる測定の結果、実施例11の方法により6価クロムの不溶化処理をした場合の6価クロムの溶出量は0.019mg/Lであった。このことから、最初に酸化マグネシウムを汚染土壌に添加・混合し、その後高炉スラグを汚染土壌に添加・混合することで、酸化マグネシウムと高炉スラグとを同時に汚染土壌に添加した場合(表4に示す実施例1)に比して、6価クロムの溶出量をより低減可能であることが確認された。 The obtained specimen was subjected to moisture curing at 20 ° C. for 7 days, and then the elution amount of hexavalent chromium was measured by diphenylcarbazide absorptiometry according to the Environmental Agency Notification No.46 method. As a result of the measurement, the elution amount of hexavalent chromium in the case of insolubilizing hexavalent chromium by the method of Example 11 was 0.019 mg / L. Therefore, when magnesium oxide and blast furnace slag are added to the contaminated soil at the same time by first adding and mixing magnesium oxide to the contaminated soil and then adding and mixing blast furnace slag to the contaminated soil (shown in Table 4) It was confirmed that the elution amount of hexavalent chromium can be further reduced as compared with Example 1).
(6)試験5
模擬汚染土壌1に、軽焼マグネシウム1を71.5kg/m3(100質量部)となるように添加してホバートミキサで1.5分間混合した後、15分間静置し、さらに高炉スラグ2を28.5kg/m3(40質量部)となるように添加してホバートミキサで1.5分間混合した(実施例12)。なお、本試験5における軽焼マグネシウム1と高炉スラグ2との添加割合は、上記表4に示す実施例1の配合割合と同一になるようにした。その後、JGS−0821「安定処理土の締固めをしない供試体作製」に準じて直径3.5cm×高さ7cmの供試体を作製した。
(6) Test 5
Light burned magnesium 1 is added to the simulated contaminated soil 1 so as to be 71.5 kg / m 3 (100 parts by mass), mixed for 1.5 minutes with a Hobart mixer, then allowed to stand for 15 minutes, and further blast furnace slag 2 Was added to 28.5 kg / m 3 (40 parts by mass) and mixed with a Hobart mixer for 1.5 minutes (Example 12). In addition, the addition ratio of the light burned magnesium 1 and the blast furnace slag 2 in this test 5 was made to be the same as the mixing ratio of Example 1 shown in Table 4 above. Thereafter, a specimen having a diameter of 3.5 cm and a height of 7 cm was prepared according to JGS-0821 “Preparation of specimen without compaction of stabilized soil”.
得られた供試体を20℃にて7日間湿空養生を行った後、6価クロムの溶出量を環境庁告示第46号法に準じて、ジフェニルカルバジド吸光光度法で測定した。かかる測定の結果、実施例12の方法により6価クロムの不溶化処理をした場合の6価クロムの溶出量は0.018mg/Lであった。このことから、最初に酸化マグネシウムを汚染土壌に添加・混合し、しばらく静置した後に高炉スラグを汚染土壌に添加・混合することで、酸化マグネシウムと高炉スラグとを同時に土壌に添加した場合(表4に示す実施例1)に比して、6価クロムの溶出量をより低減可能であることが確認された。 The obtained specimen was subjected to moisture curing at 20 ° C. for 7 days, and then the elution amount of hexavalent chromium was measured by diphenylcarbazide absorptiometry according to the Environmental Agency Notification No.46 method. As a result of the measurement, the elution amount of hexavalent chromium in the case of insolubilizing hexavalent chromium by the method of Example 12 was 0.018 mg / L. Therefore, when magnesium oxide and blast furnace slag are added to the soil at the same time by first adding and mixing magnesium oxide to the contaminated soil, and then allowing to stand for a while and then adding and mixing blast furnace slag to the contaminated soil (Table As compared with Example 1) shown in FIG. 4, it was confirmed that the elution amount of hexavalent chromium can be further reduced.
また、上記試験4及び試験5の結果から、酸化マグネシウムを汚染土壌に添加・混合した後、すぐに高炉スラグを汚染土壌に添加・混合しても、6価クロムの溶出抑制効果にほとんど有意差が見られず、両試験結果ともに優れた6価クロム溶出抑制効果を発揮し得ることが確認された。このことから、本発明の不溶化材及び不溶化方法によれば、6価クロム等の有害物質の不溶化処理を短時間で行うことができると考えられる。 In addition, from the results of Test 4 and Test 5 above, even if magnesium oxide was added / mixed to the contaminated soil and blast furnace slag was added / mixed immediately to the contaminated soil, there was almost no significant difference in the hexavalent chromium elution suppression effect. It was confirmed that the hexavalent chromium elution inhibitory effect which was excellent in both test results can be exhibited. From this, it is thought that the insolubilization process of harmful substances, such as hexavalent chromium, can be performed in a short time according to the insolubilizing material and the insolubilizing method of the present invention.
本発明の不溶化材は、6価クロム等の有害物質により汚染された土壌の不溶化処理に有用である。 The insolubilizing material of the present invention is useful for insolubilizing soil contaminated with harmful substances such as hexavalent chromium.
Claims (5)
前記高炉スラグ粉末の配合割合が、前記酸化マグネシウム100質量部に対して5〜900質量部であり、
前記不溶化材中の全酸化マグネシウムの質量に対するく溶性苦土(C−MgO)の割合が、85質量%以上であることを特徴とする不溶化材。 It contains magnesium oxide and blast furnace slag powder, and is an insolubilizing material that can insolubilize heavy metals that are harmful substances,
The blending ratio of the blast furnace slag powder is 5 to 900 parts by mass with respect to 100 parts by mass of the magnesium oxide,
The insolubilized material, wherein the ratio of soluble magnesia (C-MgO) to the mass of total magnesium oxide in the insolubilized material is 85% by mass or more.
酸化マグネシウムを前記不溶化処理対象物に添加し、混合した後、
前記酸化マグネシウムの添加量の0.05〜9倍量(質量比)の高炉スラグ粉末を、前記酸化マグネシウム及び前記高炉スラグ中の酸化マグネシウムの合計質量に対するく溶性苦土(C−MgO)の割合が85質量%以上となるように、当該不溶化処理対象物にさらに添加し、混合する
ことを特徴とする不溶化方法。 A method for insolubilizing heavy metals , which are harmful substances contained in an insolubilized object,
After adding and mixing magnesium oxide to the insolubilized object,
A ratio of 0.05 to 9 times (mass ratio) of blast furnace slag powder added to the magnesium oxide to a soluble mass of clay (C-MgO) with respect to a total mass of the magnesium oxide and magnesium oxide in the blast furnace slag. Is further added to and mixed with the insolubilization target so that the amount becomes 85% by mass or more .
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