JP2018203583A - Coal ash composition - Google Patents
Coal ash composition Download PDFInfo
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- JP2018203583A JP2018203583A JP2017112547A JP2017112547A JP2018203583A JP 2018203583 A JP2018203583 A JP 2018203583A JP 2017112547 A JP2017112547 A JP 2017112547A JP 2017112547 A JP2017112547 A JP 2017112547A JP 2018203583 A JP2018203583 A JP 2018203583A
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- coal ash
- mass
- chlorine bypass
- bypass dust
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- 239000010883 coal ash Substances 0.000 title claims abstract description 204
- 239000000203 mixture Substances 0.000 title claims abstract description 107
- 239000000460 chlorine Substances 0.000 claims abstract description 106
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 103
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 101
- 239000000428 dust Substances 0.000 claims abstract description 93
- 238000010828 elution Methods 0.000 claims abstract description 73
- 239000004568 cement Substances 0.000 claims description 42
- 239000011669 selenium Substances 0.000 claims description 28
- 229910052711 selenium Inorganic materials 0.000 claims description 24
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 claims description 22
- 239000010440 gypsum Substances 0.000 claims description 12
- 229910052602 gypsum Inorganic materials 0.000 claims description 12
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 10
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 9
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 9
- 239000004571 lime Substances 0.000 claims description 9
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 7
- 210000004556 brain Anatomy 0.000 claims description 5
- 229910001385 heavy metal Inorganic materials 0.000 abstract description 58
- 239000000463 material Substances 0.000 abstract description 52
- 239000002994 raw material Substances 0.000 abstract description 33
- 239000005447 environmental material Substances 0.000 abstract description 17
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 37
- 238000000034 method Methods 0.000 description 29
- 239000000292 calcium oxide Substances 0.000 description 19
- 235000012255 calcium oxide Nutrition 0.000 description 19
- 230000000694 effects Effects 0.000 description 16
- 239000003638 chemical reducing agent Substances 0.000 description 15
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 15
- 229910052796 boron Inorganic materials 0.000 description 14
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 13
- 230000002829 reductive effect Effects 0.000 description 13
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 11
- 239000002689 soil Substances 0.000 description 11
- 238000002156 mixing Methods 0.000 description 9
- 230000007613 environmental effect Effects 0.000 description 8
- 229910010413 TiO 2 Inorganic materials 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 229910052785 arsenic Inorganic materials 0.000 description 6
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000001723 curing Methods 0.000 description 6
- 239000011737 fluorine Substances 0.000 description 6
- 229910052731 fluorine Inorganic materials 0.000 description 6
- 239000000395 magnesium oxide Substances 0.000 description 6
- 230000001629 suppression Effects 0.000 description 6
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 5
- 239000003513 alkali Substances 0.000 description 5
- 239000011575 calcium Substances 0.000 description 5
- 229910052791 calcium Inorganic materials 0.000 description 5
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 5
- 235000011116 calcium hydroxide Nutrition 0.000 description 5
- 239000000920 calcium hydroxide Substances 0.000 description 5
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 5
- 239000011651 chromium Substances 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 238000006703 hydration reaction Methods 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 239000002956 ash Substances 0.000 description 4
- 229910052804 chromium Inorganic materials 0.000 description 4
- 239000003245 coal Substances 0.000 description 4
- 239000003112 inhibitor Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 238000010998 test method Methods 0.000 description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- -1 aluminate compound Chemical class 0.000 description 3
- 150000004645 aluminates Chemical class 0.000 description 3
- 239000011400 blast furnace cement Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 150000004683 dihydrates Chemical class 0.000 description 3
- 239000010881 fly ash Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000002893 slag Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000012085 test solution Substances 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 241001507939 Cormus domestica Species 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 238000009614 chemical analysis method Methods 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 150000004677 hydrates Chemical class 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- 239000001103 potassium chloride Substances 0.000 description 2
- 235000011164 potassium chloride Nutrition 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 239000011398 Portland cement Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910000323 aluminium silicate Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000002518 antifoaming agent Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 229940043430 calcium compound Drugs 0.000 description 1
- 150000001674 calcium compounds Chemical class 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 1
- ZOMBKNNSYQHRCA-UHFFFAOYSA-J calcium sulfate hemihydrate Chemical compound O.[Ca+2].[Ca+2].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O ZOMBKNNSYQHRCA-UHFFFAOYSA-J 0.000 description 1
- JGIATAMCQXIDNZ-UHFFFAOYSA-N calcium sulfide Chemical compound [Ca]=S JGIATAMCQXIDNZ-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001805 chlorine compounds Chemical group 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 239000010459 dolomite Substances 0.000 description 1
- 229910000514 dolomite Inorganic materials 0.000 description 1
- 229960002089 ferrous chloride Drugs 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 230000003100 immobilizing effect Effects 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 1
- SURQXAFEQWPFPV-UHFFFAOYSA-L iron(2+) sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Fe+2].[O-]S([O-])(=O)=O SURQXAFEQWPFPV-UHFFFAOYSA-L 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 150000002681 magnesium compounds Chemical class 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- PSZYNBSKGUBXEH-UHFFFAOYSA-N naphthalene-1-sulfonic acid Chemical compound C1=CC=C2C(S(=O)(=O)O)=CC=CC2=C1 PSZYNBSKGUBXEH-UHFFFAOYSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920001021 polysulfide Polymers 0.000 description 1
- 239000005077 polysulfide Substances 0.000 description 1
- 150000008117 polysulfides Polymers 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 229940000207 selenious acid Drugs 0.000 description 1
- MCAHWIHFGHIESP-UHFFFAOYSA-N selenous acid Chemical compound O[Se](O)=O MCAHWIHFGHIESP-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000007655 standard test method Methods 0.000 description 1
- IIACRCGMVDHOTQ-UHFFFAOYSA-N sulfamic acid Chemical compound NS(O)(=O)=O IIACRCGMVDHOTQ-UHFFFAOYSA-N 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Landscapes
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
Description
本発明は石炭灰組成物に関する。 The present invention relates to a coal ash composition.
石炭火力発電所から発生する石炭灰は、ＳｉＯ２やＡｌ２Ｏ３を主成分とする鉱物である石英やムライトで主に構成されており、従来、セメント原料やコンクリート混和材、埋戻し材や盛土材などの土木資材、底質改善材、水質浄化材などの環境資材として利用されている。中でも、近年の石炭灰発生量の増加に伴い、石炭灰を大量に有効利用が可能であると見込まれる土木資材や環境資材への利用が有望視されている。しかし、石炭灰は石炭由来の重金属類を含んでおり、石炭灰から土壌環境基準を超過する重金属類が溶出することが報告されている。したがって、石炭灰を土木資材あるいは環境資材に有効利用するためには、石炭灰に含まれる重金属類の溶出を抑制する必要がある。 Coal ash generated from coal-fired power plants is mainly composed of quartz and mullite, which are minerals mainly composed of SiO 2 and Al 2 O 3. Conventionally, cement raw materials, concrete admixtures, backfill materials, It is used as environmental materials such as civil engineering materials such as embankment materials, bottom quality improvement materials, and water purification materials. Among them, with the recent increase in the amount of coal ash generated, it is considered promising to use it for civil engineering materials and environmental materials that are expected to be able to effectively use a large amount of coal ash. However, coal ash contains coal-derived heavy metals, and it has been reported that heavy metals exceeding soil environmental standards are eluted from coal ash. Therefore, in order to effectively use coal ash for civil engineering materials or environmental materials, it is necessary to suppress elution of heavy metals contained in coal ash.
石炭灰中の重金属類の溶出を抑制する方法として、特許文献１には、石炭灰にセメントと還元剤と消石灰とを添加して硬化させる方法が開示されている。特許文献２には、石炭灰に還元剤とセメント、石灰、石膏等を添加して造粒する方法が開示されている。 As a method for suppressing elution of heavy metals in coal ash, Patent Document 1 discloses a method in which cement, a reducing agent, and slaked lime are added to coal ash and hardened. Patent Document 2 discloses a method of granulating by adding a reducing agent and cement, lime, gypsum and the like to coal ash.
他方、セメント工場では近年、高塩素含有廃棄物のセメント原燃料化が拡大してきており、セメントキルン内の塩素を除去するために設置されている塩素バイパス設備から発生する塩素バイパスダストの発生量が増加している。塩素バイパスダストは従来、水洗処理して塩素を除去した後にセメントに添加する方法やセメント系固化材に添加する方法で処理されてきたが、発生量の増加に伴い新たな処理方法や有効利用方法の開発が望まれている。 On the other hand, in cement factories, the use of high chlorine-containing waste as a raw material for cement has expanded in recent years, and the amount of chlorine bypass dust generated from chlorine bypass equipment installed to remove chlorine in cement kilns has increased. It has increased. Chlorine bypass dust has traditionally been treated by washing with water and removing chlorine, and then adding it to cement or adding it to cement-based solidified materials. Development is desired.
特許文献１及び２に開示される方法では、石炭灰と、セメント、石灰及び石膏のうち少なくとも一種以上とを含む石炭灰組成物を用いているため、石炭灰に含まれるフッ素、ホウ素、ヒ素及びセレンといった重金属類の不溶化効果は期待されるが、六価クロムの溶出抑制効果は期待できない。また、六価クロムの溶出を抑制するには高価な還元剤を必要とするため、材料コスト及び製品単価が高くなり、安価な材料が要求される土木資材や環境資材等への有効利用が困難となる。更に、特許文献１のように、還元剤として酸性の鉄塩のみを用いると、石炭灰組成物及び石炭灰組成物から製造した石炭灰硬化物のｐＨが低下し、ホウ素等の溶出抑制効果に悪影響を及ぼすことが懸念される。 In the methods disclosed in Patent Documents 1 and 2, since a coal ash composition containing coal ash and at least one of cement, lime, and gypsum is used, fluorine, boron, arsenic, and The effect of insolubilizing heavy metals such as selenium is expected, but the effect of inhibiting elution of hexavalent chromium cannot be expected. In addition, since an expensive reducing agent is required to suppress the elution of hexavalent chromium, the material cost and the unit price of the product increase, making it difficult to effectively use it for civil engineering and environmental materials that require inexpensive materials. It becomes. Furthermore, like patent document 1, if only an acidic iron salt is used as a reducing agent, the pH of the coal ash composition and the hardened coal ash produced from the coal ash composition is lowered, and the elution suppression effect of boron and the like is reduced. There are concerns about adverse effects.
したがって、本発明の課題は、石炭灰を含む組成物を原料として土木資材や環境資材を製造した場合に、石炭灰中の重金属類の溶出が抑制され、かつ土木資材や環境資材用の原料として安価に利用可能な石炭灰組成物を提供することにある。更に本発明の課題は、近年発生量が増加している塩素バイパスダストの有効な利用方法を提供することにある。 Therefore, the problem of the present invention is that when civil engineering materials and environmental materials are produced using a composition containing coal ash as a raw material, elution of heavy metals in coal ash is suppressed, and as a raw material for civil engineering materials and environmental materials. The object is to provide a coal ash composition that can be used at low cost. Furthermore, the subject of this invention is providing the effective usage method of the chlorine bypass dust which the generation amount has increased in recent years.
本発明者らは、石炭灰及びセメントの反応を促進する成分であるフリーライム（以下「ｆ．ＣａＯ」とも言う。）及び塩素分を含む塩素バイパスダストに着目して解析を進めた結果、塩素バイパスダストに含まれるカルシウム、アルミニウム、硫酸分及び塩素分が水和してアルミネート系化合物を生成すること、塩素バイパスダストに還元性物質が含まれること、塩素バイパスダストにｆ．ＣａＯやアルカリ分等の本発明の石炭灰組成物から硬化物を製造した場合に、硬化物のｐＨを上昇させる成分が含まれること、並びに塩素バイパスダストには重金属類を安定的に収着しやすいＴｉＯ２やＭｎＯ等の多価金属が微量成分として含まれることを見出した。本発明者らはこれらの知見に基づき、石炭灰に塩素バイパスダスト及びセメントを含む石炭灰組成物と水とを混練後、養生することで製造した石炭灰硬化物は、塩素バイパスダスト無添加の場合に比べ、石炭灰硬化物からの重金属類の溶出量を低減できることを見出し、本発明を完成させるに至った。 The present inventors proceeded with analysis focusing on chlorine-bypass dust containing free lime (hereinafter also referred to as “f.CaO”), which is a component that accelerates the reaction between coal ash and cement, and chlorine as a result. Calcium, aluminum, sulfuric acid and chlorine contained in the bypass dust are hydrated to produce an aluminate compound, the reducing substance is contained in the chlorine bypass dust, and f. When a cured product is produced from the coal ash composition of the present invention such as CaO or alkali, it contains components that increase the pH of the cured product, and the chlorine bypass dust stably sorbs heavy metals. It was found that polyvalent metals such as easy TiO 2 and MnO are contained as trace components. Based on these findings, the inventors of the present invention made a hardened coal ash by kneading a coal ash composition containing chlorine bypass dust and cement and water with coal ash, and curing the coal ash. As compared with the case, it has been found that the elution amount of heavy metals from the hardened coal ash can be reduced, and the present invention has been completed.
すなわち、本発明は、石炭灰と、塩素バイパスダストと、セメントとを含み、ブレーン比表面積が２０００〜１００００ｃｍ２／ｇである石炭灰組成物に関する。
本発明は、前記石炭灰組成物のＳｉＯ２含有量が３０〜７０質量％であり、Ａｌ２Ｏ３含有量が８〜３０質量％であり、Ｆｅ２Ｏ３含有量が１〜１０質量％であり、ＣａＯ含有量が１〜２５質量％であり、ＭｇＯ含有量が０．１〜３質量％であり、ＳＯ３含有量が０．０１〜３質量％である石炭灰組成物に関する。
本発明は、石炭灰１００質量部に対して塩素バイパスダストを０．１〜１０質量部含む石炭灰組成物に関する。
本発明は、前記塩素バイパスダストのｆ．ＣａＯ含有量が１５〜４５質量％である石炭灰組成物に関する。
本発明は、前記塩素バイパスダストのＳＯ３含有量が３〜１５質量％である石炭灰組成物に関する。本発明は、前記塩素バイパスダストのブレーン比表面積が３０００〜２００００ｃｍ２／ｇである石炭灰組成物に関する。
本発明は、前記塩素バイパスダストのセレン溶出量が０．００１〜１．０ｍｇ／Ｌである石炭灰組成物に関する。
本発明は、石炭灰１００質量部に対してセメントを３〜２５質量部含む石炭灰組成物に関する。
本発明は、前記石炭灰組成物が石炭灰１００質量部に対して、石膏を１〜１５質量部含む石炭灰組成物に関する。本発明は、前記石炭灰組成物が石炭灰１００質量部に対して、石灰を１〜１５質量部含む石炭灰組成物に関する。
That is, the present invention relates to a coal ash composition that includes coal ash, chlorine bypass dust, and cement, and has a brain specific surface area of 2000 to 10,000 cm 2 / g.
The present invention is a SiO 2 content of 30 to 70% by weight of the coal ash composition is Al 2 O 3 content of 8 to 30 mass%, Fe 2 O 3 content of 1-10 wt% , and the a CaO content of 1 to 25 wt%, a MgO content of 0.1 to 3 wt%, about coal ash composition SO 3 content of 0.01 to 3 wt%.
The present invention relates to a coal ash composition containing 0.1 to 10 parts by mass of chlorine bypass dust with respect to 100 parts by mass of coal ash.
The present invention relates to f. It is related with the coal ash composition whose CaO content is 15-45 mass%.
The present invention relates to a coal ash composition SO 3 content of the chlorine bypass dust is 3 to 15 mass%. The present invention relates to a coal ash composition in which the chlorine bypass dust has a Blaine specific surface area of 3000 to 20000 cm 2 / g.
The present invention relates to a coal ash composition in which the selenium elution amount of the chlorine bypass dust is 0.001 to 1.0 mg / L.
The present invention relates to a coal ash composition containing 3 to 25 parts by mass of cement with respect to 100 parts by mass of coal ash.
The present invention relates to a coal ash composition containing 1 to 15 parts by mass of gypsum with respect to 100 parts by mass of the coal ash. This invention relates to the coal ash composition in which the said coal ash composition contains 1-15 mass parts of lime with respect to 100 mass parts of coal ash.
本発明の石炭灰組成物は、石炭灰と、塩素バイパスダストと、セメントとを含むことにより、土木資材や環境資材用の硬化物の原料として使用することによって、硬化物からの重金属類の溶出量を土壌環境基準以下まで低減することができる。
また、本発明の石炭灰組成物は、重金属類の溶出抑制材として産業廃棄物である塩素バイパスダストを利用していることから、従来の市販の重金属類の溶出抑制材を利用した場合に比較して、安価な土木資材あるいは環境資材用の原料として利用でき、石炭灰の有効利用量の拡大を図ることができるとともに、塩素バイパスダストの有効利用を図ることができる。
The coal ash composition of the present invention contains coal ash, chlorine bypass dust, and cement, and is used as a raw material for hardened materials for civil engineering and environmental materials, thereby leaching heavy metals from the hardened material. The amount can be reduced to below soil environmental standards.
In addition, since the coal ash composition of the present invention uses chlorine bypass dust, which is industrial waste, as an elution inhibitor for heavy metals, it is compared with the case where a conventional commercially available elution inhibitor for heavy metals is used. Thus, it can be used as a raw material for inexpensive civil engineering materials or environmental materials, and the effective use of coal ash can be increased, and the chlorine bypass dust can be effectively used.
以下、本発明の好適な実施形態について詳細に説明する。なお、本発明は以下の実施形態に限定されるものではない。 Hereinafter, preferred embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment.
本発明の石炭灰組成物は、石炭灰と、塩素バイパスダストと、セメントとを含むものである。石炭灰組成物は、石炭灰と、塩素バイパスダストと、セメントとを含む混合物であり、粉末状の形態を有している。 The coal ash composition of the present invention includes coal ash, chlorine bypass dust, and cement. The coal ash composition is a mixture containing coal ash, chlorine bypass dust, and cement, and has a powdery form.
本発明で用いられる石炭灰は、石炭の燃焼によって生成したものであれば特に限定されない。例えば、石炭火力発電所にて微粉炭を燃焼した際に生成する灰であって、電気集塵機等で回収されるフライアッシュや、燃焼ボイラから落下採取されるクリンカアッシュ等が挙げられる。特にフライアッシュは、クリンカアッシュに比べて重金属類を多く含有し、その溶出量も多いため、本発明の石炭灰組成物の形態で土木資材及び／又は環境資材用の硬化物の原料として好適に有効利用される。 The coal ash used in the present invention is not particularly limited as long as it is generated by coal combustion. Examples include ash generated when pulverized coal is burned at a coal-fired power plant, and fly ash collected by an electric dust collector or the like, clinker ash dropped from a combustion boiler, and the like. In particular, fly ash contains more heavy metals than clinker ash and has a large amount of elution, so it is suitable as a raw material for hardened materials for civil engineering materials and / or environmental materials in the form of the coal ash composition of the present invention. It is used effectively.
石炭灰は、例えばヒ素（Ａｓ）、セレン（Ｓｅ）及び六価クロム（Ｃｒ６＋）等の石炭由来の重金属を含んでいる。重金属以外にも石炭灰はフッ素（Ｆ）及びホウ素（Ｂ）などの元素を含んでいる。以下の説明においては、これらの重金属及びそれ以外の元素であるフッ素やホウ素を総称して「重金属類」と言う。重金属類は石炭灰から土壌環境基準を超過して溶出する恐れがある。これらの重金属類を不溶化する方法として、セメントを添加して硬化させることで硬化物内に物理的に封じ込めて不溶化する方法や、石炭灰のポゾラン反応やセメントの水和反応により生成する水和物に固定化して不溶化する方法が知られている。フッ素、ヒ素及びセレンはこれらの方法を用いることにより、石炭灰からの溶出を十分に抑制することができる。 Coal ash contains heavy metals derived from coal such as arsenic (As), selenium (Se), and hexavalent chromium (Cr 6+ ). In addition to heavy metals, coal ash contains elements such as fluorine (F) and boron (B). In the following description, these heavy metals and other elements such as fluorine and boron are collectively referred to as “heavy metals”. Heavy metals may leach out of coal ash in excess of soil environmental standards. As a method for insolubilizing these heavy metals, cement is added and cured, and it is physically contained in the cured product and insolubilized, and coal ash pozzolanic reaction and cement hydration reaction. There is known a method of immobilizing and insolubilizing. Fluorine, arsenic and selenium can sufficiently suppress elution from coal ash by using these methods.
一方、ホウ素は、セメントの水和反応や石炭灰のポゾラン反応により生成する水和物によって不溶化されるが、中性化等によりｐＨが低下すると溶出量が増加しやすい元素である。また六価クロムは、還元剤を添加して三価クロムの形態に還元することで不溶化されるが、三価クロムの形態に還元する方法以外では溶出抑制が難しい元素である。本発明の石炭灰組成物は、その構成成分として塩素バイパスダストを含有することにより、中性化等に起因するｐＨの低下が起こりにくく、また六価クロムの溶出抑制効果をも有するため、フッ素、ホウ素、ヒ素、セレン及び六価クロムのうち少なくとも一種以上を溶出する石炭灰を好適に有効利用でき、ホウ素及び六価クロムのうち少なくとも一種以上を溶出する石炭灰をより好適に有効利用できる。 On the other hand, boron is insolubilized by a hydrate produced by cement hydration reaction or coal ash pozzolanic reaction, but it is an element whose elution amount tends to increase when pH is lowered due to neutralization or the like. Hexavalent chromium is insolubilized by adding a reducing agent and reducing it to the form of trivalent chromium, but it is difficult to suppress elution except by the method of reducing to the form of trivalent chromium. Since the coal ash composition of the present invention contains chlorine bypass dust as a constituent component thereof, it is difficult for pH to decrease due to neutralization and the like, and also has an effect of suppressing elution of hexavalent chromium. Coal ash eluting at least one or more of boron, arsenic, selenium and hexavalent chromium can be effectively used, and coal ash eluting at least one or more of boron and hexavalent chromium can be more effectively used.
本発明で用いられる石炭灰のホウ素溶出量は、０．００１〜１５ｍｇ／Ｌが好ましく、０．００１〜１０ｍｇ／Ｌがより好ましく、０．００１〜７．５ｍｇ／Ｌが更に好ましい。石炭灰のホウ素溶出量がこれらの範囲であれば、本発明の石炭灰組成物を原料として硬化物を製造した場合に、硬化物からのホウ素溶出量を土壌環境基準以下に抑制することができる。 The boron elution amount of coal ash used in the present invention is preferably 0.001 to 15 mg / L, more preferably 0.001 to 10 mg / L, and still more preferably 0.001 to 7.5 mg / L. If the boron elution amount of coal ash is within these ranges, the boron elution amount from the cured product can be suppressed below the soil environment standard when the cured product is produced using the coal ash composition of the present invention as a raw material. .
本発明で用いられる石炭灰の六価クロム溶出量は、０．００１〜０．３ｍｇ／Ｌが好ましく、０．００１〜０．２ｍｇ／Ｌがより好ましく、０．００１〜０．１ｍｇ／Ｌが更に好ましい。石炭灰の六価クロム溶出量がこれらの範囲であれば、本発明の石炭灰組成物を原料として硬化物を製造した場合に、硬化物からの六価クロム溶出量を土壌環境基準以下に抑制することができる。 The hexavalent chromium elution amount of coal ash used in the present invention is preferably 0.001 to 0.3 mg / L, more preferably 0.001 to 0.2 mg / L, and 0.001 to 0.1 mg / L. Further preferred. If the elution amount of hexavalent chromium in coal ash is within these ranges, when the cured product is produced using the coal ash composition of the present invention as a raw material, the elution amount of hexavalent chromium from the cured product is suppressed below the soil environmental standard. can do.
本発明で用いられる石炭灰のセレン溶出量は、０．０００１〜０．３ｍｇ／Ｌが好ましく、０．０００１〜０．２ｍｇ／Ｌがより好ましく、０．０００１〜０．１ｍｇ／Ｌが更に好ましい。セレンは、本発明の石炭灰組成物に含有される塩素バイパスダストからも溶出するが、石炭灰のセレン溶出量が前述の範囲であれば、本発明の石炭灰組成物を原料として硬化物を製造した場合に、硬化物からのセレン溶出量を土壌環境基準以下に抑制することができる。 The selenium elution amount of coal ash used in the present invention is preferably 0.0001 to 0.3 mg / L, more preferably 0.0001 to 0.2 mg / L, and still more preferably 0.0001 to 0.1 mg / L. . Selenium is also eluted from the chlorine bypass dust contained in the coal ash composition of the present invention, but if the selenium elution amount of coal ash is in the above-mentioned range, the cured product is obtained using the coal ash composition of the present invention as a raw material. When manufactured, the amount of selenium eluted from the cured product can be suppressed below the soil environmental standard.
石炭灰からのホウ素溶出量、六価クロム溶出量及びセレン溶出量は、後述する実施例に記載の方法によって測定される。 The boron elution amount, hexavalent chromium elution amount, and selenium elution amount from coal ash are measured by the methods described in Examples described later.
本発明で用いられる塩素バイパスダストは、セメント製造工程において塩素含有量の多い原料を使用した際に、セメント工場設備のセメントキルン内に生じる塩素分を含む排ガスの一部を塩素バイパス設備により抽気し、その抽気した排ガスを冷却した際に発生するダスト（粉状物）のことである。塩素バイパスダストは、塩化カリウムなどの塩化物、ｆ．ＣａＯなどのセメント原料の仮焼物等により構成される。本発明において、塩素バイパスダストは、本発明の石炭灰組成物を原料として製造した硬化物からの重金属類の溶出抑制材として好適に含有される。 The chlorine bypass dust used in the present invention, when using a raw material with a high chlorine content in the cement manufacturing process, bleeds part of the exhaust gas containing chlorine generated in the cement kiln of the cement factory equipment by the chlorine bypass equipment. It is dust (powder) generated when the extracted exhaust gas is cooled. Chlorine bypass dust is a chloride such as potassium chloride, f. It is composed of a calcined material of cement raw material such as CaO. In the present invention, the chlorine bypass dust is suitably contained as an elution inhibitor for heavy metals from a cured product produced using the coal ash composition of the present invention as a raw material.
塩素バイパスダストが、本発明の石炭灰組成物を原料として製造した硬化物からの重金属類の溶出抑制材としての効果を有する理由は明らかではないが、本発明者は以下のように推測している。
（１）塩素バイパスダストに含まれるｆ．ＣａＯや塩化カリウムが石炭灰のポゾラン反応及び／又はセメントの水和反応を促進する作用があることから、石炭灰組成物を原料として硬化物を製造した場合に硬化物の硬化が促進され、石炭灰に含まれる重金属類が硬化物内に物理的に封じ込められる効果が向上するとともに、重金属類を固定化する水和物の生成量が増加することで溶出抑制効果が向上するものと考えられる。
（２）塩素バイパスダストはカルシウム、アルミニウム、硫酸分及び塩素分を含み、塩素バイパスダスト中のカルシウム及びアルミニウムと、硫酸分と塩素分とのうち少なくとも一方の成分とが水和して重金属類を取り込むアルミネート系化合物が生成することから、塩素バイパスダストを添加することで、本発明の石炭灰組成物から硬化物を製造した場合に、六価クロムやその他重金属類が石炭灰硬化物中に不溶化される効果が高まるものと考えられる。
（３）塩素バイパスダストはｆ．ＣａＯに加えてアルカリ分を更に含むことから、石炭灰組成物を硬化物とした場合に、硬化物のｐＨが上昇することにより、ｐＨの高い領域で不溶化されやすいホウ素の溶出抑制効果が向上するものと考えられる。
（４）本発明者らは検討を進めたところ、前記セメントキルンの窯尻近傍から抽気された排ガスのガス雰囲気は酸素濃度が低く、還元性物質が生成しやすいことに起因して、塩素バイパスダスト中に還元性物質が含まれていることが判った。この還元性物質によって、六価クロムが三価クロムに還元されることにより溶出抑制効果が向上するものと考えられる。
なお本発明者は、塩素バイパスダストに６価のセレン酸と４価の亜セレン酸とが共存していることを実測しており、塩素バイパスダストが還元雰囲気に曝されていることを確認している。
（５）塩素バイパスダストは、ＴｉＯ２やＭｎＯ等の多価金属を微量成分として含有することから、重金属類がこれらの多価金属に収着しやすいことによって、石炭灰組成物を硬化物とした場合に重金属類の溶出が抑制されるものと考えられる。
The reason why the chlorine bypass dust has an effect as an elution inhibitor of heavy metals from the cured product produced from the coal ash composition of the present invention is not clear, but the present inventor presumes as follows Yes.
(1) f. Contained in chlorine bypass dust. Since CaO and potassium chloride have an action of promoting the pozzolanic reaction of coal ash and / or the hydration reaction of cement, when the cured product is produced using the coal ash composition as a raw material, the curing of the cured product is promoted. The effect that the heavy metals contained in the ash are physically contained in the cured product is improved, and the elution suppression effect is considered to be improved by increasing the amount of hydrates that immobilize the heavy metals.
(2) Chlorine bypass dust contains calcium, aluminum, sulfuric acid and chlorine, and calcium and aluminum in the chlorine bypass dust and at least one component of sulfuric acid and chlorine are hydrated to remove heavy metals. Since the aluminate-based compound to be taken in is produced, when a hardened product is produced from the coal ash composition of the present invention by adding chlorine bypass dust, hexavalent chromium and other heavy metals are contained in the hardened coal ash. It is thought that the effect of insolubilization increases.
(3) Chlorine bypass dust is f. Since it further contains an alkali component in addition to CaO, when the coal ash composition is used as a cured product, the pH of the cured product increases, thereby improving the boron elution suppression effect that is easily insolubilized in a high pH region. It is considered a thing.
(4) As a result of investigations by the present inventors, the gas atmosphere of the exhaust gas extracted from the vicinity of the kiln bottom of the cement kiln has a low oxygen concentration, and it is easy to generate reducing substances. It was found that reducing substances were contained in the dust. It is considered that this reducing substance improves the elution suppression effect by reducing hexavalent chromium to trivalent chromium.
The present inventor has actually measured that hexavalent selenate and tetravalent selenious acid coexist in the chlorine bypass dust, and confirmed that the chlorine bypass dust is exposed to the reducing atmosphere. ing.
(5) Chlorine bypass dust contains polyvalent metals such as TiO 2 and MnO as trace components, so that heavy metals easily sorb on these polyvalent metals, thereby converting the coal ash composition into a cured product. In this case, it is considered that elution of heavy metals is suppressed.
本発明の石炭灰組成物に含有される塩素バイパスダストの量は、石炭灰１００質量部に対して０．１〜１０質量部が好ましく、０．５〜５質量部がより好ましく、１〜３質量部が更に好ましい。塩素バイパスダストの量が０．１質量部未満では石炭灰に含まれる重金属類の溶出抑制効果が得られない。塩素バイパスダストの量が１０質量部を超えると、石炭灰からのセレン溶出量が前記範囲であっても、塩素バイパスダストに含まれるセレンが石炭灰組成物を原料として製造した硬化物から溶出することによって、石炭灰と塩素バイパスダストとの合計セレン溶出量が土壌環境基準を超過する可能性があるため好ましくない。 0.1-10 mass parts is preferable with respect to 100 mass parts of coal ash, and, as for the quantity of the chlorine bypass dust contained in the coal ash composition of this invention, 0.5-5 mass parts is more preferable, 1-3 Part by mass is more preferable. If the amount of chlorine bypass dust is less than 0.1 parts by mass, the elution suppression effect of heavy metals contained in coal ash cannot be obtained. When the amount of chlorine bypass dust exceeds 10 parts by mass, even if the amount of selenium eluted from coal ash is within the above range, selenium contained in the chlorine bypass dust is eluted from the cured product produced using the coal ash composition as a raw material. Therefore, the total selenium elution amount of coal ash and chlorine bypass dust may exceed the soil environment standard, which is not preferable.
本発明の石炭灰組成物に含有される塩素バイパスダストのセレン溶出量は、０．００１〜１．０ｍｇ／Ｌが好ましく、０．００１〜０．７５ｍｇ／Ｌがより好ましく、０．００１〜０．５ｍｇ／Ｌが更に好ましい。塩素バイパスダストのセレン溶出量が１．０ｍｇ／Ｌを超えると、石炭灰からのセレン溶出量や石炭灰組成物に含有される塩素バイパスダストの量が前記範囲であっても、石炭灰組成物を原料として製造した硬化物からのセレン溶出量が土壌環境基準を超過する可能性があるため好ましくない。塩素バイパスダストのセレン溶出量は、後述する実施例に記載の方法によって測定される。 The selenium elution amount of the chlorine bypass dust contained in the coal ash composition of the present invention is preferably 0.001 to 1.0 mg / L, more preferably 0.001 to 0.75 mg / L, and 0.001 to 0 More preferably, 5 mg / L. When the selenium elution amount of the chlorine bypass dust exceeds 1.0 mg / L, even if the selenium elution amount from the coal ash or the amount of the chlorine bypass dust contained in the coal ash composition is within the above range, the coal ash composition Since the selenium elution amount from the hardened | cured material manufactured by using as a raw material may exceed a soil environmental standard, it is unpreferable. The selenium elution amount of the chlorine bypass dust is measured by the method described in the examples described later.
塩素バイパスダストのｆ．ＣａＯ含有量は、１５〜４５質量％が好ましく、２０〜４０質量％がより好ましく、２５〜３５質量％が更に好ましい。ｆ．ＣａＯ含有量が１５質量％未満であると、本発明の石炭灰組成物を原料として硬化物を製造した場合に、石炭灰のポゾラン反応及び／又はセメントの水和反応の促進及び／又は硬化物のｐＨが上昇することによる硬化物からの重金属類の溶出抑制効果が不十分となり好ましくない。また、４５質量％を超えるような塩素バイパスダストは塩素バイパス設備からの排出量が少なく、実用性に乏しいため好ましくない。塩素バイパスダストのｆ．ＣａＯ含有量は、後述する実施例に記載の方法によって測定される。 Chlorine bypass dust f. The CaO content is preferably 15 to 45% by mass, more preferably 20 to 40% by mass, and still more preferably 25 to 35% by mass. f. When the cured product is produced using the coal ash composition of the present invention as the raw material when the CaO content is less than 15% by mass, the promotion of the coal ash pozzolanic reaction and / or the cement hydration reaction and / or the cured product The effect of suppressing the elution of heavy metals from the cured product due to the increase in pH of the cured product becomes insufficient, which is not preferable. Further, chlorine bypass dust exceeding 45% by mass is not preferable because the amount of discharge from the chlorine bypass facility is small and practicality is poor. Chlorine bypass dust f. The CaO content is measured by the method described in Examples described later.
塩素バイパスダストのＣｌ含有量は、１〜２０質量％が好ましく、５〜１５質量％がより好ましく、１０〜１２．５質量％が更に好ましい。塩素バイパスダストのＣｌ含有量が１質量％未満であると、本発明の石炭灰組成物を原料として硬化物を製造した場合に、石炭灰のポゾラン反応及び／又はセメントの水和反応を促進することによる硬化物からの重金属類の溶出抑制効果が不十分となり好ましくない。また、塩素バイパスダストのＣｌ含有量が２０質量％を超えるような塩素バイパスダストは、塩素バイパス設備からの排出量が少なく、実用性に乏しいため好ましくない。塩素バイパスダストのＣｌ含有量は、後述する実施例に記載の方法によって測定される。 The Cl content of the chlorine bypass dust is preferably 1 to 20% by mass, more preferably 5 to 15% by mass, and still more preferably 10 to 12.5% by mass. When the Cl content of the chlorine bypass dust is less than 1% by mass, when the cured product is produced using the coal ash composition of the present invention as a raw material, the pozzolanic reaction of coal ash and / or the hydration reaction of cement is promoted. This is not preferable because the effect of suppressing elution of heavy metals from the cured product is insufficient. Chlorine bypass dust in which the chlorine content of the chlorine bypass dust exceeds 20% by mass is not preferable because the amount of discharge from the chlorine bypass facility is small and practicality is poor. The Cl content of the chlorine bypass dust is measured by the method described in Examples described later.
塩素バイパスダストのＳＯ３含有量は、３〜１５質量％が好ましく、５〜１２．５質量％がより好ましく、７．５〜１０質量％が更に好ましい。ＳＯ３含有量が前記範囲であれば、塩素バイパスダスト、石炭灰、セメントに含まれるカルシウム、アルミニウム等と反応して重金属類を固定化するアルミネート系水和物を生成することにより、本発明の石炭灰組成物を原料として製造した硬化物からの重金属類の溶出量がより低減されるため好ましい。塩素バイパスダストのＳＯ３含有量は、後述する実施例に記載の方法によって測定される。 The SO 3 content of the chlorine bypass dust is preferably 3 to 15% by mass, more preferably 5 to 12.5% by mass, and still more preferably 7.5 to 10% by mass. If the SO 3 content is within the above range, the present invention can be obtained by reacting with chlorine bypass dust, coal ash, calcium contained in cement, aluminum, etc. to produce an aluminate hydrate that immobilizes heavy metals. Since the elution amount of heavy metals from the hardened | cured material manufactured using the coal ash composition of this as a raw material is reduced more, it is preferable. The SO 3 content of the chlorine bypass dust is measured by the method described in Examples described later.
塩素バイパスダストのＡｌ２Ｏ３含有量は、１〜１０質量％が好ましく、２〜７．５質量％がより好ましく、３〜５質量％が更に好ましい。Ａｌ２Ｏ３含有量が前記範囲であれば、重金属類を固定化するアルミネート系水和物の生成により、本発明の石炭灰組成物を原料として製造した硬化物からの重金属類の溶出量がより低減されるため好ましい。塩素バイパスダストのＡｌ２Ｏ３含有量は、後述する実施例に記載の方法によって測定される。 The content of Al 2 O 3 in the chlorine bypass dust is preferably 1 to 10% by mass, more preferably 2 to 7.5% by mass, and still more preferably 3 to 5% by mass. If the Al 2 O 3 content is within the above range, the elution amount of heavy metals from the cured product produced from the coal ash composition of the present invention as a raw material by the production of an aluminate hydrate that immobilizes heavy metals. Is preferable because it is further reduced. The Al 2 O 3 content of the chlorine bypass dust is measured by the method described in Examples described later.
塩素バイパスダストのアルカリ（Ｒ２Ｏ）含有量は、３〜１５質量％が好ましく、５〜１３質量％がより好ましく、７〜１１質量％が更に好ましい。アルカリ含有量が前記範囲であれば、石炭灰硬化物のｐＨが上昇し、本発明の石炭灰組成物を原料として製造した硬化物からの重金属類の溶出がより低減されるため好ましい。本明細書において、アルカリ（Ｒ２Ｏ）のＲは、Ｎａ又はＫを表す。塩素バイパスダストのアルカリ（Ｒ２Ｏ）含有量は、後述する実施例に記載の方法によって算出される。 Alkaline chlorine bypass dust (R 2 O) content is preferably 3 to 15 wt%, more preferably from 5 to 13 mass%, still more preferably 7 to 11 wt%. If alkali content is the said range, since pH of coal ash hardened | cured material rises and the elution of heavy metals from the hardened | cured material manufactured using the coal ash composition of this invention as a raw material is reduced, it is preferable. In the present specification, R in the alkali (R 2 O) represents Na or K. The alkali (R 2 O) content of the chlorine bypass dust is calculated by the method described in Examples described later.
塩素バイパスダストのＴｉＯ２含有量は、０．０５〜０．５質量％が好ましく、０．１〜０．４質量％がより好ましく、０．１５〜０．３５質量％が更に好ましい。ＴｉＯ２含有量が前記範囲であれば、本発明の石炭灰組成物を原料として製造した硬化物からの重金属類の溶出がより低減されるため好ましい。塩素バイパスダストのＴｉＯ２含有量は、後述する実施例に記載の方法によって測定される。 The TiO 2 content of the chlorine bypass dust is preferably 0.05 to 0.5% by mass, more preferably 0.1 to 0.4% by mass, and still more preferably 0.15 to 0.35% by mass. When the TiO 2 content is in the above range, it is preferable because elution of heavy metals from a cured product produced using the coal ash composition of the present invention as a raw material is further reduced. The TiO 2 content of the chlorine bypass dust is measured by the method described in Examples described later.
塩素バイパスダストのＭｎＯ含有量は、０．００１〜０．２質量％が好ましく、０．００５〜０．１５質量％がより好ましく、０．０１〜０．１質量％が更に好ましい。ＭｎＯ含有量が前記範囲であれば、本発明の石炭灰組成物を原料として製造した硬化物からの重金属類の溶出がより低減されるため好ましい。塩素バイパスダストのＭｎＯ含有量は、後述する実施例に記載の方法によって測定される。 The MnO content of the chlorine bypass dust is preferably 0.001 to 0.2% by mass, more preferably 0.005 to 0.15% by mass, and still more preferably 0.01 to 0.1% by mass. If MnO content is the said range, since elution of heavy metals from the hardened | cured material manufactured using the coal ash composition of this invention as a raw material is reduced more, it is preferable. The MnO content of the chlorine bypass dust is measured by the method described in the examples described later.
塩素バイパスダストのブレーン比表面積は、３０００〜２００００ｃｍ２／ｇが好ましく、４０００〜１５０００ｃｍ２／ｇがより好ましく、５０００〜１００００ｃｍ２／ｇが更に好ましい。ブレーン比表面積が前記範囲であれば、石炭灰組成物を原料として硬化物を製造する際に、塩素バイパスダストは硬化物中で十分に反応することができ、硬化物からの重金属類の溶出がより低減されるため好ましい。ブレーン比表面積の測定方法は後述する実施例において詳述する。 Blaine specific surface area of the chlorine bypass dust is preferably 3000~20000cm 2 / g, more preferably 4000~15000cm 2 / g, more preferably 5000~10000cm 2 / g. If the Blaine specific surface area is within the above range, when producing a cured product from the coal ash composition, the chlorine bypass dust can sufficiently react in the cured product, and the elution of heavy metals from the cured product Since it is further reduced, it is preferable. The method for measuring the specific surface area of branes will be described in detail in the examples described later.
本発明に用いられるセメントは、特に限定されるものではなく、普通ポルトランドセメント、高炉セメント、早強セメント等が挙げられる。六価クロムの溶出抑制及び塩素バイパスダストとの反応性の観点から、高炉スラグを含有する高炉セメントを用いることが好ましい。石炭灰組成物に含有されるセメント量は、石炭灰１００質量部に対して３〜２５質量部が好ましく、５〜２０質量部がより好ましく、１０〜１５質量部が更に好ましい。石炭灰組成物に含有されるセメント量が３質量部未満であると、石炭灰組成物を原料として製造した硬化物からの重金属類の溶出抑制効果が不十分となり、２５質量部を超えると材料コストが高くなるため好ましくない。 The cement used in the present invention is not particularly limited, and examples thereof include ordinary Portland cement, blast furnace cement, and early strength cement. From the viewpoint of suppressing elution of hexavalent chromium and reactivity with chlorine bypass dust, it is preferable to use blast furnace cement containing blast furnace slag. The amount of cement contained in the coal ash composition is preferably 3 to 25 parts by mass, more preferably 5 to 20 parts by mass, and still more preferably 10 to 15 parts by mass with respect to 100 parts by mass of coal ash. If the amount of cement contained in the coal ash composition is less than 3 parts by mass, the effect of suppressing elution of heavy metals from the cured product produced from the coal ash composition as a raw material becomes insufficient, and if it exceeds 25 parts by mass, the material This is not preferable because the cost increases.
上述の各成分を含有する本発明の石炭灰組成物は、そのブレーン比表面積が、２０００〜１００００ｃｍ２／ｇであることが好ましく、３０００〜８０００ｃｍ２／ｇであることがより好ましく、４０００〜６０００ｃｍ２／ｇであることが更に好ましく、４５００〜５５００ｃｍ２／ｇであることが最も好ましい。ブレーン比表面積が前記範囲であることによって、石炭灰組成物を原料として硬化物を製造するときに、石炭灰、セメント及び塩素バイパスダストが硬化物中で十分に反応することができ、硬化物からの重金属類の溶出がより低減されるという効果が奏される。ブレーン比表面積は、後述する実施例の方法を用いて測定することができる。 The coal ash composition of the present invention containing the above-mentioned components preferably has a brane specific surface area of 2000 to 10000 cm 2 / g, more preferably 3000 to 8000 cm 2 / g, and 4000 to 6000 cm. 2 / g is more preferable, and 4500-5500 cm 2 / g is most preferable. When the brane specific surface area is in the above range, when producing a cured product using the coal ash composition as a raw material, the coal ash, cement and chlorine bypass dust can sufficiently react in the cured product. There is an effect that elution of heavy metals is further reduced. The specific surface area of branes can be measured by using the method of Examples described later.
本発明の石炭灰組成物は、ＳｉＯ２含有量が３０〜７０質量％であり、Ａｌ２Ｏ３含有量が８〜３０質量％であり、Ｆｅ２Ｏ３含有量が１〜１０質量％であり、ＣａＯ含有量が１〜２５質量％であり、ＭｇＯ含有量が０．１〜３質量％であり、ＳＯ３含有量が０．０１〜３質量％であることが好ましく、ＳｉＯ２含有量が４０〜６０質量％であり、Ａｌ２Ｏ３含有量が１５〜２５質量％であり、Ｆｅ２Ｏ３含有量が３〜７質量％であり、ＣａＯ含有量が３〜２０質量％であり、ＭｇＯ含有量が０．５〜２質量％であり、ＳＯ３含有量が０．１〜２質量％であることがより好ましい。これらの化合物の含有量が前記範囲であることによって、石炭灰組成物を原料として硬化物を製造するときに、重金属類を取り込む水和物の生成や硬化物のｐＨの上昇に起因して、硬化物からの重金属の溶出がより低減されるという効果が奏される。前記化合物の含有量は、後述する実施例の方法を用いて測定することができる。前記化合物の含有量は、石炭灰と、塩素バイパスダストと、セメントとの混合割合を、前述の含有範囲を満たす範囲で変化させることによっても調整することができる。 The coal ash composition of the present invention has an SiO 2 content of 30 to 70% by mass, an Al 2 O 3 content of 8 to 30% by mass, and an Fe 2 O 3 content of 1 to 10% by mass. Yes, CaO content is 1 to 25% by mass, MgO content is 0.1 to 3% by mass, SO 3 content is preferably 0.01 to 3% by mass, SiO 2 content Is 40 to 60% by mass, Al 2 O 3 content is 15 to 25% by mass, Fe 2 O 3 content is 3 to 7% by mass, and CaO content is 3 to 20% by mass. More preferably, the MgO content is 0.5 to 2% by mass and the SO 3 content is 0.1 to 2% by mass. When the content of these compounds is in the above range, when producing a cured product from the coal ash composition as a raw material, due to the formation of hydrates that take in heavy metals and the increase in the pH of the cured product, There is an effect that elution of heavy metal from the cured product is further reduced. Content of the said compound can be measured using the method of the Example mentioned later. The content of the compound can also be adjusted by changing the mixing ratio of coal ash, chlorine bypass dust, and cement within a range that satisfies the content range described above.
本発明の石炭灰組成物には、更に石膏が含まれていてもよい。本発明で使用される石膏としては、例えば二水石膏、半水石膏、無水石膏が挙げられる。石炭灰組成物に含有される石膏の量は、石炭灰１００質量部に対して二水石膏換算で１〜１５質量部が好ましく、３〜１２．５質量部がより好ましく、５〜１０質量部が更に好ましい。二水石膏換算の石膏量が３質量部未満であると、石炭灰組成物を原料として製造した硬化物からの重金属類の溶出抑制効果が得られず、１５質量部を超えると該硬化物からの重金属類の溶出抑制効果は高まるが、材料コストが高くなるため好ましくない。 The coal ash composition of the present invention may further contain gypsum. Examples of the gypsum used in the present invention include dihydrate gypsum, hemihydrate gypsum, and anhydrous gypsum. The amount of gypsum contained in the coal ash composition is preferably 1 to 15 parts by mass, more preferably 3 to 12.5 parts by mass, and more preferably 5 to 10 parts by mass with respect to 100 parts by mass of coal ash. Is more preferable. When the amount of gypsum in terms of dihydrate gypsum is less than 3 parts by mass, the effect of suppressing elution of heavy metals from the cured product produced from the coal ash composition as a raw material cannot be obtained, and when the amount exceeds 15 parts by mass, Although the elution suppression effect of heavy metals increases, it is not preferable because the material cost increases.
本発明の石炭灰組成物には、更に石灰が含まれていてもよい。本発明で使用される石灰としては、消石灰及び生石灰が挙げられる。石炭灰組成物に含有される石灰の量は、消石灰を例にすると、石炭灰１００質量部に対して１〜１５質量部が好ましく、３〜１２．５質量部がより好ましく、５〜１０質量部が更に好ましい。消石灰の量が１質量部未満であると、石炭灰組成物を原料として製造した硬化物からの重金属類の溶出抑制効果が得られず、１５質量部を超えると材料コストが高くなるため好ましくない。また、石炭灰組成物に含有される石灰の量は、生石灰を例にすると、石炭灰１００質量部に対して１〜１１．５質量部が好ましく、２〜９．５質量部がより好ましく、３〜７．５質量部が更に好ましい。 The coal ash composition of the present invention may further contain lime. Examples of lime used in the present invention include slaked lime and quicklime. The amount of lime contained in the coal ash composition is preferably 1 to 15 parts by mass, more preferably 3 to 12.5 parts by mass with respect to 100 parts by mass of coal ash when slaked lime is taken as an example. Part is more preferred. If the amount of slaked lime is less than 1 part by mass, the effect of suppressing elution of heavy metals from the cured product produced from the coal ash composition as a raw material cannot be obtained, and if it exceeds 15 parts by mass, the material cost increases, which is not preferable. . The amount of lime contained in the coal ash composition is preferably 1 to 11.5 parts by mass, more preferably 2 to 9.5 parts by mass with respect to 100 parts by mass of coal ash when quick lime is taken as an example. 3-7.5 mass parts is still more preferable.
また、本発明の石炭灰組成物は、本発明の効果を阻害しない範囲で塩化第一鉄、硫酸第一鉄、多硫化カルシウム、硫化カルシウムなどの還元剤、高炉スラグ、炭酸カルシウムなどのカルシウム化合物、酸化マグネシウム、水酸化マグネシウム、ドロマイトなどのマグネシウム化合物を更に含んでいてもよい。 Further, the coal ash composition of the present invention is a reducing compound such as ferrous chloride, ferrous sulfate, calcium polysulfide, and calcium sulfide within a range not inhibiting the effects of the present invention, and calcium compounds such as blast furnace slag and calcium carbonate. Further, magnesium compounds such as magnesium oxide, magnesium hydroxide and dolomite may be further contained.
本発明の石炭灰組成物は、石炭灰に塩素バイパスダストとセメントを添加・混合することによって製造できるので、特別な混合設備や製造設備を必要としない。このように製造された石炭灰組成物は、石炭灰と塩素バイパスダストとセメントとの混合物であって、粉末状の形態を有するため、重金属類の溶出がなく、一般的な粉末と同様の方法で保管、流通することができる。 Since the coal ash composition of the present invention can be produced by adding and mixing chlorine bypass dust and cement to coal ash, no special mixing equipment or production equipment is required. The coal ash composition thus produced is a mixture of coal ash, chlorine bypass dust, and cement, and has a powdery form, so there is no elution of heavy metals, and the same method as general powder Can be stored and distributed.
本発明の石炭灰組成物は、水を加えて養生し硬化させ硬化物を製造した場合に、硬化物からの重金属類の溶出が環境基準以下に抑制されている。このことに起因して、土木資材や環境資材の原料として好適に利用することができる。本発明の石炭灰組成物を原料として製造可能な土木資材の用途例としては、埋戻し材、路盤材、盛土材、埋立材、地盤改良材、裏込め材、空洞充填材等のスラリー材、等が挙げられる。環境資材の用途例としては、底質改善材や水質浄化材等が挙げられる。 When the coal ash composition of the present invention is cured by adding water and cured to produce a cured product, elution of heavy metals from the cured product is suppressed to an environmental standard or less. Because of this, it can be suitably used as a raw material for civil engineering materials and environmental materials. Examples of civil engineering materials that can be produced using the coal ash composition of the present invention as a raw material include backfill materials, roadbed materials, embankment materials, landfill materials, ground improvement materials, backfill materials, slurry materials such as cavity fillers, Etc. Examples of uses of environmental materials include bottom quality improving materials and water purification materials.
本発明の石炭灰組成物を原料とした土木資材及び／又は環境資材の製造方法としては、本発明の石炭灰組成物と水とを混練し、得られた湿潤状態の混練物を養生して硬化させる方法、前記混練物を更に造粒して得られた造粒物を養生して硬化させる方法、石炭灰組成物と水とを混合してスラリーとし、前記スラリーを型枠に打設して硬化させる方法等、公知の方法を適用することができる。また、本発明の石炭灰組成物は粉末状の組成物であるため、工事現場にて土木資材及び／又は環境資材に適宜加工して利用することが可能であり、利便性が高いものである。 As a method for producing civil engineering materials and / or environmental materials using the coal ash composition of the present invention as a raw material, the coal ash composition of the present invention and water are kneaded, and the obtained wet kneaded material is cured. A method of curing, a method of curing and curing the granulated product obtained by further granulating the kneaded product, a coal ash composition and water are mixed to form a slurry, and the slurry is placed in a mold A known method such as a curing method can be applied. Moreover, since the coal ash composition of the present invention is a powdery composition, it can be used by appropriately processing it into civil engineering materials and / or environmental materials at a construction site, and is highly convenient. .
本発明の石炭灰組成物を原料とした土木資材及び／又は環境資材の製造の際に、本発明の効果を阻害しない範囲で他の材料と混合して利用することもできる。他の材料としては、例えば減水剤、ＡＥ剤、消泡剤、収縮低減剤、凝結促進剤、凝結遅延剤、増粘剤などが挙げられる。これらの材料は、土木資材及び／又は環境資材に求められる性能に応じて、これらのうち一種を単独で使用してもよいし、複数を組み合わせて使用してもよい。 In the production of civil engineering materials and / or environmental materials using the coal ash composition of the present invention as a raw material, it can also be used by mixing with other materials within a range that does not impair the effects of the present invention. Examples of other materials include water reducing agents, AE agents, antifoaming agents, shrinkage reducing agents, setting accelerators, setting retarders, and thickeners. These materials may be used alone or in combination of two or more depending on the performance required for civil engineering materials and / or environmental materials.
石炭灰組成物を原料とした土木資材及び／又は環境資材の製造の際に減水剤を配合させる場合、リグニン系、ナフタレンスルホン酸系、アミノスルホン酸系、ポリカルボン酸系の減水剤、高性能減水剤、高性能ＡＥ減水剤等を使用することができる。減水剤の配合量は、石炭灰１００質量部に対して０．１〜１０質量部であることが好ましく、１〜５質量部であることがより好ましい。 When mixing water reducing agents in the production of civil engineering materials and / or environmental materials made from coal ash composition, lignin-based, naphthalene sulfonic acid-based, amino sulfonic acid-based, polycarboxylic acid-based water reducing agents, high performance A water reducing agent, a high performance AE water reducing agent, etc. can be used. It is preferable that the compounding quantity of a water reducing agent is 0.1-10 mass parts with respect to 100 mass parts of coal ash, and it is more preferable that it is 1-5 mass parts.
以下に、本発明について実施例及び比較例を挙げて詳細に説明する。なお、本発明はこれらの例によって限定されるものではない。 Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. Note that the present invention is not limited to these examples.
〔１．石炭灰〕
石炭灰には、石炭火力発電所の電気集塵機で回収されたフライアッシュを使用した。使用した石炭灰の重金属類溶出量を表１に示す。表１に示す分析値は、平成３年環境庁告示第４６号付表に準拠して溶出試験を行って得た検液の重金属類濃度を、ＪＩＳ Ｋ ００１２「工場排水試験方法」に準拠して測定した値である。なお、以下の土壌環境基準は、平成３年環境庁告示第４６号別表の記載を用いた。
[1. (Coal ash)
For the coal ash, fly ash recovered with an electric dust collector at a coal-fired power plant was used. Table 1 shows the amount of heavy metals eluted from the coal ash used. Analytical values shown in Table 1 are based on JIS K 0012 “Factory drainage test method” for the concentration of heavy metals in the test solution obtained from the elution test in accordance with Appendix No. 46 of the 1991 Environment Agency Notification. It is a measured value. In addition, the following soil environment standard used the description of the 1991 Environment Agency notification 46 separate table.
〔２．塩素バイパスダスト〕
使用した塩素バイパスダストの性状を、以下の表２に示す。表２に示す分析値は以下の方法で測定した値である。
（ｉ）ＳｉＯ２、Ａｌ２Ｏ３、Ｆｅ２Ｏ３、ＣａＯ、ＭｇＯ、ＳＯ３、Ｎａ２Ｏ、Ｋ２Ｏ、Ｒ２Ｏ、ＴｉＯ２、ＭｎＯ含有量
ＳｉＯ２、Ａｌ２Ｏ３、Ｆｅ２Ｏ３、ＣａＯ、ＭｇＯ、ＳＯ３、Ｎａ２Ｏ、Ｋ２Ｏ、ＴｉＯ２、ＭｎＯ含有量は、ＪＩＳ Ｍ ８８５３「セラミックス用アルミノけい酸塩質原料の化学分析方法」を参考にして測定した。
Ｒ２Ｏ含有量は、上記の方法により測定したＮａ２Ｏ及びＫ２Ｏの含有量（質量％）から、下記の式（１）により算出した。なお、「０．６５８」はＫ２ＯをＮａ２Ｏのモル当量に換算する係数である。
Ｒ２Ｏ含有量（質量％）＝Ｎａ２Ｏ含有量＋（０．６５８×Ｋ２Ｏ含有量） ・・・（１）
（ii）ｆ．ＣａＯ含有量
ｆ．ＣａＯ含有量は、セメント協会標準試験方法のＪＣＡＳ Ｉ−０１：１９９７「遊離酸化カルシウムの定量方法」に準拠して測定した。
（iii）Ｃｌ、Ｓｅ含有量
Ｃｌ及びＳｅ含有量は、ＪＩＳ Ｒ ５２０２「セメントの化学分析方法」に準拠して測定した。
（iv）Ｓｅ溶出量
Ｓｅ溶出量は、平成３年環境庁告示第４６号付表に準拠して検液を作製し、その検液のＳｅ濃度をＪＩＳ Ｋ ０１０２「工場排水試験方法」に準拠して測定した。
（v）ブレーン比表面積
ブレーン比表面積は、ＪＩＳ Ｒ ５２０１：１９９７「セメントの物理試験方法」に従い、ブレーン空気透過装置を用いて測定した。
[2. Chlorine bypass dust)
The properties of the used chlorine bypass dust are shown in Table 2 below. The analytical values shown in Table 2 are values measured by the following method.
(I) SiO 2 , Al 2 O 3 , Fe 2 O 3 , CaO, MgO, SO 3 , Na 2 O, K 2 O, R 2 O, TiO 2 , MnO content SiO 2 , Al 2 O 3 , Fe 2 O 3 , CaO, MgO, SO 3 , Na 2 O, K 2 O, TiO 2 and MnO content were measured with reference to JIS M 8853 “Chemical analysis method of aluminosilicate materials for ceramics”. .
The R 2 O content was calculated from the Na 2 O and K 2 O content (% by mass) measured by the above method according to the following formula (1). “0.658” is a coefficient for converting K 2 O into a molar equivalent of Na 2 O.
R 2 O content (mass%) = Na 2 O content + (0.658 × K 2 O content) (1)
(Ii) f. CaO content f. The CaO content was measured in accordance with JCAS I-01: 1997 “Method for Quantifying Free Calcium Oxide” of the Cement Association Standard Test Method.
(Iii) Cl and Se contents Cl and Se contents were measured in accordance with JIS R 5202 "Cement chemical analysis method".
(Iv) Se elution amount The Se elution amount was prepared in accordance with the Appendix of Environment Agency Notification No. 46 in 1991, and the Se concentration of the test solution was determined in accordance with JIS K 0102 “Factory drainage test method”. Measured.
(V) Brain specific surface area The brain specific surface area was measured using a brain air permeation apparatus in accordance with JIS R 5201: 1997 “Cement physical test method”.
〔３．石炭灰組成物の作製〕
前記石炭灰と塩素バイパスダスト、高炉セメントＢ種（宇部三菱セメント社製）、二水石膏（排煙脱硫石膏）及び消石灰（宇部マテリアルズ社製、ＪＩＳ特号）をポリ袋に投入し、ポリ袋を手でよく振って混合することで石炭灰組成物を作製した。石炭灰組成物は、石炭灰に対する塩素バイパスダストの配合量を変化させて、石炭灰組成物Ａ〜Ｆの６種類を作製した。また、作製した各石炭灰組成物のブレーン比表面積を前述の塩素バイパスダストのブレーン比表面積と同様の方法で測定した。石炭灰組成物Ａ〜Ｆにおける各材料の配合割合及びブレーン比表面積の測定結果を併せて表３に示す。
[3. Preparation of coal ash composition)
The coal ash and chlorine bypass dust, blast furnace cement type B (manufactured by Ube-Mitsubishi Cement), dihydrate gypsum (exhaust gas desulfurization gypsum) and slaked lime (manufactured by Ube Materials, JIS special name) are put into a plastic bag, The coal ash composition was prepared by shaking the bag well by hand and mixing. The coal ash composition produced six types of coal ash compositions A to F by changing the blending amount of the chlorine bypass dust with respect to the coal ash. Moreover, the brane specific surface area of each produced coal ash composition was measured by the same method as that of the above-mentioned chlorine bypass dust. Table 3 shows the blending ratio of each material in the coal ash compositions A to F and the measurement result of the Blaine specific surface area.
〔４．石炭灰硬化物の作製〕
前記石炭灰組成物Ａ〜Ｆを得た後、ポリカルボン酸系減水剤（ＢＡＳＦ社製、マスターグレニウムＳＰ８ＳＶ）と石炭灰組成物Ａ〜Ｆがスラリー化する量の水を添加してホバートミキサー（ホバート・ジャパン株式会社製の型番：Ｎ５０）を用いて５９１ｒｐｍで１０分間混練した。得られた混練物を長方形の容器に投入し、振動を加えてスラリー状にして容器内に均一に充填した後、１日密封養生して硬化させた。硬化体を容器から脱型し、１０〜１５ｍｍの粒度に切断して石炭灰硬化物Ａ’〜Ｆ’を得た。石炭灰硬化物Ａ’〜Ｆ’は、石炭灰組成物Ａ〜Ｆを使用してそれぞれ製造したものである。石炭灰硬化物の配合割合を表４に示す。
[4. (Production of hardened coal ash)
After obtaining the coal ash compositions A to F, a polycarboxylic acid-based water reducing agent (manufactured by BASF, master glenium SP8SV) and water in an amount to make the coal ash compositions A to F slurry are added to a Hobart mixer. (Model number: N50 manufactured by Hobart Japan Co., Ltd.) was used and kneaded at 591 rpm for 10 minutes. The obtained kneaded material was put into a rectangular container, and was shaken to form a slurry, which was uniformly filled in the container, and then cured by sealing for one day. The cured body was removed from the container and cut to a particle size of 10 to 15 mm to obtain hardened coal ash A ′ to F ′. Coal ash hardened | cured material A'-F 'is manufactured using coal ash composition A-F, respectively. Table 4 shows the blending ratio of the hardened coal ash.
〔４．石炭灰硬化物の重金属類溶出量の評価〕
以下に示すとおり、石炭灰硬化物Ａ’〜Ｆ’からの重金属類溶出量を評価した。
[4. (Evaluation of heavy metal elution from hardened coal ash)
As shown below, the heavy metal elution amount from hardened coal ash A'-F 'was evaluated.
〔実施例１〕
石炭灰１００質量部に対して塩素バイパスダストを０．５質量部添加して調製した石炭灰組成物Ａから作製した石炭灰硬化物Ａ’を２８日間湿空養生した後、重金属類の溶出量を評価した。重金属類の溶出量の評価は、ＪＩＳ Ｋ ００５８−１の５「スラグ類の化学物質試験方法」に準拠して検液を作製し、その検液のｐＨ及びＢ、Ｓｅ、Ｃｒ６＋濃度をＪＩＳ Ｋ ０１０２「工場排水試験方法」に準拠して測定した。結果を表５に示す。
[Example 1]
After the cured coal ash A ′ prepared from the coal ash composition A prepared by adding 0.5 parts by mass of chlorine bypass dust to 100 parts by mass of coal ash is wet-air cured for 28 days, the amount of elution of heavy metals Evaluated. Evaluation of the elution amount of heavy metals is made according to JIS K 0058-1 5 “Testing methods for chemical substances in slags”, and the pH, B, Se, and Cr 6+ concentration of the test solution are measured according to JIS. Measured according to K 0102 “Factory drainage test method”. The results are shown in Table 5.
〔実施例２〕
石炭灰１００質量部に対して塩素バイパスダストを１質量部添加して調製した石炭灰組成物Ｂから作製した石炭灰硬化物Ｂ’を用いた以外は、実施例１と同様の方法で石炭灰硬化物からの重金属類の溶出量を評価した。結果を表５に示す。
[Example 2]
Coal ash is produced in the same manner as in Example 1 except that the hardened coal ash B ′ prepared from the coal ash composition B prepared by adding 1 part by weight of chlorine bypass dust to 100 parts by weight of coal ash is used. The amount of elution of heavy metals from the cured product was evaluated. The results are shown in Table 5.
〔実施例３〕
石炭灰１００質量部に対して塩素バイパスダストを２質量部添加して調製した石炭灰組成物Ｃから作製した石炭灰硬化物Ｃ’を用いた以外は、実施例１と同様の方法で石炭灰硬化物からの重金属類の溶出量を評価した。結果を表５に示す。
Example 3
Coal ash is produced in the same manner as in Example 1 except that the hardened coal ash C ′ prepared from the coal ash composition C prepared by adding 2 parts by weight of chlorine bypass dust to 100 parts by weight of coal ash is used. The amount of elution of heavy metals from the cured product was evaluated. The results are shown in Table 5.
〔実施例４〕
石炭灰１００質量部に対して塩素バイパスダストを５質量部添加して調製した石炭灰組成物Ｄから作製した石炭灰硬化物Ｄ’を用いた以外は、実施例１と同様の方法で石炭灰硬化物からの重金属類の溶出量を評価した。結果を表５に示す。
Example 4
Coal ash is produced in the same manner as in Example 1 except that the hardened coal ash D ′ prepared from the coal ash composition D prepared by adding 5 parts by weight of chlorine bypass dust to 100 parts by weight of coal ash is used. The amount of elution of heavy metals from the cured product was evaluated. The results are shown in Table 5.
〔実施例５〕
石炭灰１００質量部に対して塩素バイパスダストを１０質量部添加して調製した石炭灰組成物Ｅから作製した石炭灰硬化物Ｅ’を用いた以外は、実施例１と同様の方法で石炭灰硬化物からの重金属類の溶出量を評価した。結果を表５に示す。
Example 5
Coal ash is produced in the same manner as in Example 1 except that a hardened coal ash E ′ prepared from a coal ash composition E prepared by adding 10 parts by mass of chlorine bypass dust to 100 parts by mass of coal ash is used. The amount of elution of heavy metals from the cured product was evaluated. The results are shown in Table 5.
〔比較例１〕
塩素バイパスダストを添加せずに調製した石炭灰組成物Ｆから作製した石炭灰硬化物Ｆ’を用いた以外は、実施例１と同様の方法で石炭灰硬化物からの重金属類の溶出量を評価した。結果を表５に示す。
[Comparative Example 1]
The amount of elution of heavy metals from the hardened coal ash was the same as in Example 1 except that the hardened coal ash F ′ prepared from the coal ash composition F prepared without adding chlorine bypass dust was used. evaluated. The results are shown in Table 5.
表５に示す実施例１〜５及び比較例１より、塩素バイパスダストを添加した石炭灰硬化物Ａ’〜Ｅ’では、塩素バイパスダスト無添加の石炭灰硬化物Ｆ’と比較して、ホウ素及び六価クロムの溶出量が低減されていることが判る。石炭灰硬化物からのセレン溶出量は塩素バイパスダストの添加量の増加に伴って増加傾向であるものの、塩素バイパスダストの添加量を本発明の範囲内に設定することによって、セレンの溶出量を土壌環境基準以下に抑制できることが判った。なお、フッ素及びヒ素の溶出量はここでは示していないが、実施例１〜５におけるフッ素及びヒ素の溶出量は土壌環境基準以下であった。 From Examples 1 to 5 and Comparative Example 1 shown in Table 5, in the hardened coal ash A ′ to E ′ to which chlorine bypass dust was added, boron was compared with the hardened coal ash F ′ to which no chlorine bypass dust was added. It can also be seen that the elution amount of hexavalent chromium is reduced. Although the amount of selenium eluted from the hardened coal ash tends to increase as the amount of added chlorine bypass dust increases, the amount of selenium eluted can be reduced by setting the amount of added chlorine bypass dust within the scope of the present invention. It was found that it can be controlled below the soil environmental standard. In addition, although the elution amounts of fluorine and arsenic are not shown here, the elution amounts of fluorine and arsenic in Examples 1 to 5 were below the soil environment standard.
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| JP2018158876A (en) * | 2017-03-24 | 2018-10-11 | 宇部興産株式会社 | Coal ash hardened material |
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| JP7200006B2 (en) | 2019-02-27 | 2023-01-06 | Ｕｂｅ三菱セメント株式会社 | fly ash composition |
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