JPH08309310A - Treatment method for incinerated fly ash containing heavy metal - Google Patents
Treatment method for incinerated fly ash containing heavy metalInfo
- Publication number
- JPH08309310A JPH08309310A JP7119634A JP11963495A JPH08309310A JP H08309310 A JPH08309310 A JP H08309310A JP 7119634 A JP7119634 A JP 7119634A JP 11963495 A JP11963495 A JP 11963495A JP H08309310 A JPH08309310 A JP H08309310A
- Authority
- JP
- Japan
- Prior art keywords
- fly ash
- heavy metals
- iron
- heavy metal
- ions
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 229910001385 heavy metal Inorganic materials 0.000 title claims abstract description 99
- 239000010881 fly ash Substances 0.000 title claims abstract description 49
- 238000000034 method Methods 0.000 title claims abstract description 34
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 76
- 229910052742 iron Inorganic materials 0.000 claims abstract description 39
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims abstract description 32
- 150000002500 ions Chemical class 0.000 claims abstract description 30
- 229910001448 ferrous ion Inorganic materials 0.000 claims abstract description 28
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 26
- 239000000725 suspension Substances 0.000 claims abstract description 18
- 229960004887 ferric hydroxide Drugs 0.000 claims abstract description 16
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 claims abstract description 16
- 239000000126 substance Substances 0.000 claims abstract description 12
- 239000002253 acid Substances 0.000 claims abstract description 11
- 239000007864 aqueous solution Substances 0.000 claims abstract description 10
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 9
- 239000011707 mineral Substances 0.000 claims abstract description 9
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229910001447 ferric ion Inorganic materials 0.000 claims abstract description 5
- 239000000203 mixture Substances 0.000 claims abstract description 5
- 239000007800 oxidant agent Substances 0.000 claims abstract description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 18
- 239000002956 ash Substances 0.000 claims description 15
- 239000007788 liquid Substances 0.000 claims description 15
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 12
- 239000011790 ferrous sulphate Substances 0.000 claims description 8
- 235000003891 ferrous sulphate Nutrition 0.000 claims description 8
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims description 8
- 239000000243 solution Substances 0.000 claims description 8
- 235000010755 mineral Nutrition 0.000 claims description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 4
- 239000011133 lead Substances 0.000 claims description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 4
- 230000001376 precipitating effect Effects 0.000 claims description 4
- 229910052785 arsenic Inorganic materials 0.000 claims description 3
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 claims description 3
- 239000011651 chromium Substances 0.000 claims description 3
- 239000011701 zinc Substances 0.000 claims description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 2
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 claims description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- 229910052770 Uranium Inorganic materials 0.000 claims description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 2
- 229910052787 antimony Inorganic materials 0.000 claims description 2
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 claims description 2
- 229910052790 beryllium Inorganic materials 0.000 claims description 2
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 claims description 2
- 229910052793 cadmium Inorganic materials 0.000 claims description 2
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims description 2
- 229910052804 chromium Inorganic materials 0.000 claims description 2
- 229910017052 cobalt Inorganic materials 0.000 claims description 2
- 239000010941 cobalt Substances 0.000 claims description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 239000010949 copper Substances 0.000 claims description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052737 gold Inorganic materials 0.000 claims description 2
- 239000010931 gold Substances 0.000 claims description 2
- 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 claims description 2
- 238000005259 measurement Methods 0.000 claims description 2
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 claims description 2
- 229910052753 mercury Inorganic materials 0.000 claims description 2
- 229910052750 molybdenum Inorganic materials 0.000 claims description 2
- 239000011733 molybdenum Substances 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 230000001590 oxidative effect Effects 0.000 claims description 2
- 229910052697 platinum Inorganic materials 0.000 claims description 2
- 229910052711 selenium Inorganic materials 0.000 claims description 2
- 239000011669 selenium Substances 0.000 claims description 2
- 229910052709 silver Inorganic materials 0.000 claims description 2
- 239000004332 silver Substances 0.000 claims description 2
- 229910052718 tin Inorganic materials 0.000 claims description 2
- 239000011135 tin Substances 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 claims description 2
- 229910052720 vanadium Inorganic materials 0.000 claims description 2
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 2
- 229910052725 zinc Inorganic materials 0.000 claims description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims 1
- 229910052700 potassium Inorganic materials 0.000 claims 1
- 239000011591 potassium Substances 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 9
- 238000000975 co-precipitation Methods 0.000 abstract description 6
- 238000006243 chemical reaction Methods 0.000 abstract description 5
- 230000007935 neutral effect Effects 0.000 abstract description 5
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 24
- 230000000052 comparative effect Effects 0.000 description 12
- 230000003647 oxidation Effects 0.000 description 12
- 238000007254 oxidation reaction Methods 0.000 description 12
- 239000007787 solid Substances 0.000 description 12
- 239000000706 filtrate Substances 0.000 description 11
- 239000000047 product Substances 0.000 description 11
- 239000002244 precipitate Substances 0.000 description 10
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 8
- -1 iron (III) ions Chemical class 0.000 description 8
- 235000011121 sodium hydroxide Nutrition 0.000 description 8
- 239000002699 waste material Substances 0.000 description 8
- 238000010828 elution Methods 0.000 description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 5
- 239000010789 controlled waste Substances 0.000 description 5
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 4
- 230000009471 action Effects 0.000 description 4
- 239000000428 dust Substances 0.000 description 4
- 239000002440 industrial waste Substances 0.000 description 4
- 238000007664 blowing Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 238000010306 acid treatment Methods 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- GCPXMJHSNVMWNM-UHFFFAOYSA-N arsenous acid Chemical compound O[As](O)O GCPXMJHSNVMWNM-UHFFFAOYSA-N 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 229960002089 ferrous chloride Drugs 0.000 description 2
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 2
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 239000006228 supernatant Substances 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 229910001430 chromium ion Inorganic materials 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 235000014413 iron hydroxide Nutrition 0.000 description 1
- 229910021506 iron(II) hydroxide Inorganic materials 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- 238000010169 landfilling Methods 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 150000002978 peroxides Chemical class 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 229940072033 potash Drugs 0.000 description 1
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Substances [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 1
- 235000015320 potassium carbonate Nutrition 0.000 description 1
- 235000011118 potassium hydroxide Nutrition 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000002516 radical scavenger Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 229940001593 sodium carbonate Drugs 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000004071 soot Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Landscapes
- Fire-Extinguishing Compositions (AREA)
- Processing Of Solid Wastes (AREA)
- Compounds Of Iron (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、一般廃棄物、産業廃
棄物、特別管理廃棄物の焼却飛灰中に存在する重金属類
を不溶化して無害にする方法に関する。廃棄物中の重金
属成分は焼却飛灰中に濃縮されて存在し、一部は水溶性
なので、焼却飛灰をそのまま廃棄すると有害な重金属類
による環境汚染を招く。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for insolubilizing heavy metals present in incineration fly ash of general waste, industrial waste and specially controlled waste to render them harmless. Heavy metal components in waste are concentrated in incinerator fly ash, and some of them are water-soluble, so discarding incinerator fly ash as it is causes environmental pollution by harmful heavy metals.
【０００２】[0002]
【従来の技術】従来、重金属類を含む灰汚水に３価の鉄
イオンを加え、更に苛性ソーダ等を加えてｐＨを中性又
は弱アルカリに調整すると、水酸化鉄が生成する際に共
存する様々な重金属類イオンが沈殿物に取り込まれ灰汚
水を清澄することが経験的に知られている。これは水酸
化第２鉄の共沈作用によるもので、この効果をスカベン
シャーと呼んでおり、重金属類イオンを含む廃液のみな
らず、焼却灰、焼却飛灰を含んだ灰汚水に対しても効果
的であることが知られている。しかしながら、近年、環
境関連の法規制が厳しくなる傾向にあり、特別管理廃棄
物に至っては重金属類の溶出基準が改正され、Ｐｂ等規
制値が１桁厳しくなったものもある。このような新基準
の下では、単に重金属類イオンを水酸化第２鉄と共沈さ
せるだけでは安定化効果が不充分となり、何らかの対応
が迫られることになった。一方、重金属類イオンを含む
廃液処理については、フェライトを生成させるフェライ
ト法、具体的には高温酸化法、常温酸化法、２段酸化
法、還元法、２液法等が知られている。フェライト化を
１回の操作で行なう方法（高温酸化法：特公昭57-31955
号、特公昭60-36826号、特開平6-269763号）では亜ヒ酸
が除去されにくい等の欠点があり、常温酸化法および還
元法では反応操作が難しくなる傾向にあり、２液法では
ランニングコストが高くなるなど不具合が生じた。２段
酸化法（特開昭59-21678号）は反応が２段必要であり、
またフェライトの磁気的材料としての利用が難しい等の
不利な点はあったが、液中の重金属類の安定化に対して
極めて有効で、かつランニングコストも安価であった。
しかし重金属類を含む焼却飛灰の処理には適しなかっ
た。2. Description of the Related Art Conventionally, when iron (III) ions are added to ash sewage containing heavy metals and the pH is adjusted to neutral or weak alkali by adding caustic soda, various coexistence occurs when iron hydroxide is produced. It is empirically known that various heavy metal ions are taken into the precipitate to clarify ash sewage. This is due to the coprecipitation action of ferric hydroxide, and this effect is called scavenger, and not only for waste liquid containing heavy metal ions, but also for ash wastewater containing incinerated ash and incinerated fly ash. It is known to be effective. However, in recent years, environment-related laws and regulations have become stricter, and in the case of specially controlled waste, the elution standard for heavy metals has been revised, and in some cases the Pb and other regulatory values have become stricter by one digit. Under such new standards, simply coprecipitating heavy metal ions with ferric hydroxide results in an insufficient stabilizing effect, and some action is required. On the other hand, as a waste liquid treatment containing heavy metal ions, a ferrite method for producing ferrite, specifically, a high temperature oxidation method, a room temperature oxidation method, a two-stage oxidation method, a reduction method, a two-liquid method, and the like are known. A method of performing ferrite formation in a single operation (high temperature oxidation method: Japanese Patent Publication No. 57-31955)
JP-B No. 60-36826 and JP-A No. 6-269763) have drawbacks such as difficulty in removing arsenous acid, and the reaction operation tends to be difficult in the room temperature oxidation method and the reduction method, and in the two-liquid method. Problems such as high running costs have occurred. The two-step oxidation method (JP-A-59-21678) requires two steps of reaction,
Further, although there are disadvantages such as difficulty in using ferrite as a magnetic material, it is extremely effective for stabilizing heavy metals in a liquid and the running cost is low.
However, it was not suitable for incineration fly ash containing heavy metals.
【０００３】[0003]
【発明が解決しようとする課題】本発明は、従来適切な
処理方法がなかった一般廃棄物、産業廃棄物、特別管理
廃棄物の焼却飛灰中に存在する重金属類を不溶化して無
害にする方法を提供することを目的とする。DISCLOSURE OF THE INVENTION The present invention renders the heavy metals present in the incineration fly ash of general waste, industrial waste, and specially controlled waste, which had not been adequately treated conventionally, insolubilized and rendered harmless. The purpose is to provide a method.
【０００４】[0004]
【課題を解決するための手段】本発明にかかわる重金属
類含有焼却飛灰の処理方法は、（１）重金属類を含有す
る焼却飛灰に鉱酸水溶液を加えｐＨを４以下に調整し重
金属類を溶出して焼却飛灰中の酸不溶成分が懸濁してい
る液を形成させる第１工程、（２）懸濁液中に溶出して
いる第１鉄イオンと鉄以外の重金属類イオンを測定し、
必要に応じて第１鉄塩を添加して懸濁液中の第１鉄イオ
ンと鉄以外の重金属類イオンとのモル比を６：１〜８
０：１に調整し更にアルカリ物質を加えて中性付近に維
持しながら酸化剤を加えて前記第１鉄イオンを酸化して
第２鉄イオンにすると共に鉄以外の重金属類イオンを水
酸化第２鉄との共沈生成物として沈澱させる第２工程、
及び（３）得られた共沈生成物に第２工程におけるモル
比調整後存在した第１鉄イオンに対しモル比で約半量に
相当する第１鉄イオンを加え更にアルカリ物質を加えて
ｐＨ９〜１１に調整し約６０〜１００℃にて撹拌するこ
とにより前記共沈生成物をフェライトとし鉄以外の重金
属類イオンを前記フェライトに吸蔵させ焼却飛灰中の酸
不溶成分と共に分離する第３工程とよりなることを特徴
とする。Means for Solving the Problems The method of treating incinerated fly ash containing heavy metals according to the present invention is as follows: (1) The pH of the incinerator fly ash containing heavy metals is adjusted to 4 or less by adding an aqueous solution of mineral acid. Process to form a liquid in which the acid-insoluble components in the incineration fly ash are suspended, (2) Measurement of ferrous iron and heavy metal ions other than iron dissolved in the suspension Then
If necessary, a ferrous salt is added to adjust the molar ratio of ferrous ions in the suspension to heavy metal ions other than iron in the range of 6: 1 to 8
It is adjusted to 0: 1, and an alkaline substance is added to maintain the neutrality, and an oxidizing agent is added to oxidize the ferrous ions to ferric ions and to hydrate heavy metal ions other than iron. 2nd step of precipitating as a coprecipitation product with 2 iron,
And (3) to the obtained coprecipitated product, ferrous ions corresponding to about half the molar ratio to ferrous ions present after the molar ratio adjustment in the second step are added, and an alkaline substance is further added to adjust the pH to 9 to 10. The third step of adjusting to 11 and stirring at about 60 to 100 ° C. to make the coprecipitated product ferrite and occlude heavy metal ions other than iron in the ferrite to separate it together with the acid-insoluble component in the fly ash. Is characterized in that
【０００５】本発明において重金属類を含有する焼却飛
灰とは、一般廃棄物、産業廃棄物、特別管理廃棄物を焼
却する焼却施設から生じ集塵装置で集められた飛灰（煤
塵）を言い、主成分はシリカ、アルミナなどである。乾
式集塵装置を用いた場合の焼却飛灰は乾燥微粉、湿式集
塵装置を用いた場合の焼却飛灰は懸濁液又はスラリー状
となっているが、本発明はどちらにも適用される。焼却
飛灰には排ガス処理の際に投入されるアルカリ成分が混
入するため、焼却飛灰は通常アルカリ性となっている。
また重金属類は飛灰中に高濃度で存在し、水分が存在す
る場合は一部が溶けてイオン化している。重金属類は、
鉄、銅、亜鉛、ニッケル、錫、鉛、アンチモン、カドミ
ウム、クロム、ベリリウム、チタン、マンガン、コバル
ト、バナジウム、セレン、モリブテン、ウラン、白金、
金、銀、水銀などで、本発明においてはヒ素をも含む。
これらの重金属類は単独であっても、また２種類以上で
あっても、さらにその形態が錯体であっても本発明によ
り処理することができる。重金属類イオンの含有量は特
に限定されず、上限はパーセント・オーダーで下限はｐ
ｐｍオーダーのものであっても本発明により処理するこ
とができる。In the present invention, the incinerated fly ash containing heavy metals means fly ash (soot dust) collected from a dust collector from an incinerator for incinerating general waste, industrial waste and specially controlled waste. The main components are silica and alumina. The incinerated fly ash when using the dry dust collector is a dry fine powder, and the incinerator fly ash when using the wet dust collector is in the form of suspension or slurry, but the present invention is applicable to both . Since the incineration fly ash is mixed with an alkaline component that is introduced during the treatment of exhaust gas, the incinerator fly ash is usually alkaline.
Heavy metals are present in fly ash at a high concentration, and when water is present, some are dissolved and ionized. Heavy metals are
Iron, copper, zinc, nickel, tin, lead, antimony, cadmium, chromium, beryllium, titanium, manganese, cobalt, vanadium, selenium, molybdenum, uranium, platinum,
Gold, silver, mercury, etc., and also includes arsenic in the present invention.
These heavy metals can be treated according to the present invention alone, in two or more kinds, and in the form of a complex. The content of heavy metal ions is not particularly limited, the upper limit is percent order, and the lower limit is p.
Even the pm order can be processed by the present invention.
【０００６】本発明のプロセスでは、先ず、第１工程と
して、重金属類を含有する焼却飛灰に鉱酸水溶液を加え
ｐＨを４以下に調整し重金属類を溶出してイオン化し、
焼却飛灰中の酸不溶成分が懸濁している液を形成させ
る。同時に、この酸処理によってクロムイオン等は還元
され、フェライト化されやすいイオン状態になる。飛灰
中の灰分（重金属以外のシリカ、アルミナ等の無機成
分）中に熱拡散し固溶体化した重金属類は殆ど溶出され
ない。この時点で懸濁液中の灰分は無害なものとなる。
この段階で無害化された灰分を分離して埋立などの処理
をすることも可能であるが、灰分を分離せずに第２工程
以下の処理をすることによりフェライト化した重金属類
の吸蔵が効果的に行なわれる。鉱酸としては硫酸、塩
酸、硝酸のいずれでも使用できるが、コスト及び取り扱
いの容易さの点で特に硫酸が好ましい。特に飛灰中にカ
ルシウムが含まれている場合、酸として硫酸を用いるこ
とにより沈殿する硫酸カルシウムは次の第２工程で生成
する重金属類の共沈物の吸蔵に有効である。また硫酸カ
ルシウムを沈殿させることにより溶液中の塩濃度を低く
抑えることができフェライト化がより容易になる等の利
点が生じる。In the process of the present invention, first, as a first step, an aqueous mineral acid solution is added to incineration fly ash containing heavy metals to adjust the pH to 4 or less, and the heavy metals are eluted and ionized,
It forms a liquid in which the acid-insoluble components in the fly ash are suspended. At the same time, chromium ions and the like are reduced by this acid treatment, resulting in an ionic state that facilitates ferrite formation. The heavy metals which are thermally diffused into the ash (inorganic components such as silica and alumina other than heavy metals) in the fly ash to form a solid solution are hardly eluted. At this point the ash in the suspension is harmless.
Although it is possible to separate the ash detoxified at this stage for landfilling, etc., it is effective to occlude the ferritic heavy metals by performing the second and subsequent steps without separating the ash. Will be performed. As the mineral acid, any of sulfuric acid, hydrochloric acid and nitric acid can be used, but sulfuric acid is particularly preferable in terms of cost and ease of handling. In particular, when calcium is contained in fly ash, calcium sulfate precipitated by using sulfuric acid as an acid is effective for occluding the heavy metal coprecipitate generated in the next second step. Further, by precipitating calcium sulfate, the salt concentration in the solution can be suppressed to a low level, and there are advantages such as facilitating the formation of ferrite.
【０００７】次に第２工程として、第１工程で得られた
懸濁液中に溶出している第１鉄イオンと鉄以外の重金属
類イオンを測定する。溶出している第１鉄イオンと鉄以
外の重金属類イオンとのモル比がこの段階で６：１〜８
０：１の範囲にあればそのままアルカリ物質を加えて中
性付近にすれば良いが、溶出している第１鉄イオンと鉄
以外の重金属類イオンとのモル比がこの段階で６：１未
満であれば第１鉄塩を添加して懸濁液中の第１鉄イオン
と鉄以外の重金属類イオンとのモル比を６：１〜８０：
１の範囲に調整し、さらにアルカリ物質を加えて水酸化
第２鉄が生成する条件となるように中性付近、好ましく
はｐＨ５．５〜７．０、そして温度を室温〜５０℃に維
持しながら酸化剤を加えて前記第１鉄イオンを酸化して
第２鉄イオンにすると共に鉄以外の重金属類イオンを水
酸化第２鉄との共沈生成物として沈澱させる。この工程
で重要なことは、懸濁液中の第１鉄イオンと鉄以外の重
金属類イオンとのモル比を６：１〜８０：１、好ましく
は６：１〜６０：１の範囲に調整することである。後述
の比較例に示すように、このモル比が６未満の場合に
は、第３工程で分離される固形分より溶出する重金属及
び濾液中の重金属類が多く満足すべき結果が得られな
い。モル比が８０以上でも効果に変りはないがコスト高
になる。共沈物生成の際に夾雑物として含まれる灰分は
この共沈物を吸蔵するのに有効であり、その作用は灰分
の濃度数千ｐｐｍ以上、粒径数百ミクロン以下の場合に
特に効果的である。これら灰分は除去されにくい亜ヒ酸
などの共沈作用も有するので、これらのフェライト化を
も促進し除去効果を高める作用も有する。焼却飛灰中に
カルシウムが含まれている場合には、第１工程で酸とし
て硫酸を用いることにより沈殿する硫酸カルシウムも灰
分と同様、この共沈物の吸蔵に有効である。また硫酸カ
ルシウムを沈殿させることにより溶液中の塩濃度を低く
抑えることができ、第３工程でのフェライト化がより容
易になる等の利点が生じる。添加する第１鉄塩としては
硫酸第１鉄、塩化第１鉄、又は硝酸第１鉄を水溶液の状
態で使用する。アルカリ物質としては苛性ソーダ、苛性
カリ、炭酸ソーダ、炭酸カリ、消石灰などを水溶液の状
態で使用する。アルカリ物質を加えて中性付近に調整し
た段階で白色又は青緑色の沈殿物が生成するが、これは
主に水酸化第１鉄である。この液に空気を吹き込んで強
力に酸化すると茶褐色の沈殿物が生成する。なお空気酸
化に代えて酸化性ガス、過酸化物もしくは酸素酸を用い
て酸化を行なっても良い。この茶褐色の沈殿物は主に水
酸化第２鉄であるが、これが生成する段階で様々な重金
属類イオンが取り込まれ、これらの共沈物となってい
る。共沈物を生成させる温度は常温で良いが、加熱して
も良い。この水酸化第２鉄の共沈生成物は沈降性が良い
ので、そのまま放置すると上澄液とスラッジを分離する
ことができ、上澄液中には重金属類イオンは含まれな
い。しかしながらこの段階でのスラッジは重金属類を充
分安定化できず、重金属類の溶出に対する新基準を満足
できないケースも発生する。Next, in the second step, the ferrous iron ions and heavy metal ions other than iron eluted in the suspension obtained in the first step are measured. The molar ratio of the eluted ferrous ion to heavy metal ions other than iron is 6: 1 to 8 at this stage.
If it is in the range of 0: 1, the alkaline substance may be added as it is to make it near neutral, but the molar ratio of the eluted ferrous ion to heavy metal ions other than iron is less than 6: 1 at this stage. If so, the ferrous salt is added and the molar ratio of ferrous ions in the suspension to heavy metal ions other than iron is 6: 1 to 80:
Adjust to a range of 1, and add an alkaline substance to maintain ferric hydroxide at a neutral temperature, preferably pH 5.5 to 7.0, and maintain the temperature at room temperature to 50 ° C. While adding an oxidizing agent, the ferrous ions are oxidized to ferric ions, and heavy metal ions other than iron are precipitated as a coprecipitation product with ferric hydroxide. What is important in this step is to adjust the molar ratio of ferrous ions in the suspension to heavy metal ions other than iron in the range of 6: 1 to 80: 1, preferably 6: 1 to 60: 1. It is to be. As shown in Comparative Examples described later, when the molar ratio is less than 6, a large amount of heavy metals eluted from the solid content separated in the third step and heavy metals in the filtrate cannot be obtained with satisfactory results. Even if the molar ratio is 80 or more, the effect does not change, but the cost increases. The ash contained as a contaminant during coprecipitate formation is effective in storing this coprecipitate, and its action is particularly effective when the ash concentration is several thousand ppm or more and the particle size is several hundreds of microns or less. Is. Since these ash components also have a coprecipitation action on arsenous acid and the like, which are difficult to remove, they also promote the ferritization of these substances and enhance the removal effect. When the incineration fly ash contains calcium, calcium sulfate precipitated by using sulfuric acid as an acid in the first step is also effective for occluding this coprecipitate, like ash. Further, by precipitating calcium sulfate, the salt concentration in the solution can be suppressed to a low level, and there are advantages such as facilitation of ferritic conversion in the third step. As the ferrous iron salt to be added, ferrous sulfate, ferrous chloride, or ferrous nitrate is used in the state of an aqueous solution. As the alkaline substance, caustic soda, caustic potash, sodium carbonate, potash carbonate, slaked lime, etc. are used in the form of an aqueous solution. A white or blue-green precipitate is formed at the stage of adjusting to near neutrality by adding an alkaline substance, which is mainly ferrous hydroxide. A dark brown precipitate is formed when air is blown into this solution and it is strongly oxidized. Instead of air oxidation, oxidizing gas, peroxide or oxyacid may be used for the oxidation. This brown-colored precipitate is mainly ferric hydroxide, and various heavy metal ions are incorporated at the stage where it is produced, and they are coprecipitates. The temperature at which the coprecipitate is generated may be room temperature, but may be heated. The co-precipitated product of ferric hydroxide has a good settling property, so that the supernatant and sludge can be separated when left as it is, and the supernatant does not contain heavy metal ions. However, the sludge at this stage cannot sufficiently stabilize heavy metals, and in some cases, the new standard for elution of heavy metals cannot be satisfied.
【０００８】最後に第３工程として、第２工程で得られ
た共沈生成物を含む液に第２工程におけるモル比調整後
存在した第１鉄イオン、即ち第１工程における鉱酸処理
により溶出した第１鉄イオン及び第２工程で添加した第
１鉄塩より生じる第１鉄イオンの合計量（酸化により水
酸化第２鉄に転化する量）に対しモル比で約半量に相当
する第１鉄イオンを加え更にアルカリ物質を加えてｐＨ
９〜１１に調整し約６０〜１００℃のフェライト生成条
件下にて撹拌する。反応が進むにつれて茶褐色の沈殿物
は黒色となり、沈殿物の物性が大巾に変化する。この黒
色沈殿物は主にフェライトであり、水酸化第２鉄に比べ
て沈降性、濃縮性及び脱水性が飛躍的に向上する。そし
て、共沈生成物をフェライトに転換させると、共沈生成
物中の鉄以外の重金属類イオンがフェライトに吸蔵され
化学的に安定となる。この化学的構造については不明で
あるが、自然界の磁鉄鋼や砂鉄などと同様に、フェライ
トが生成する段階で他の重金属類イオンがフェライトの
結晶格子中に取り込まれて化学的に安定となり、一旦吸
蔵された重金属類イオンは水に溶出しなくなるためであ
ると考えられる。これを焼却飛灰中の酸不溶成分と共に
分離する。一方、フェライトを分離した液側に残留する
重金属類イオン濃度は１０-1〜１０-3ｐｐｍ単位もしく
はこれ以下であり、必要によりｐＨを調整すれば、放流
はもとより再利用もできる。第１鉄イオン源としては硫
酸第１鉄、塩化第１鉄、硝酸第１鉄、或は酸洗廃液など
の第１鉄イオンを含むものを使用できる。このようにし
て、本発明によれば、重金属類の溶出に対する新基準を
満足することが可能である。Finally, in the third step, the ferrous ions present in the liquid containing the coprecipitation product obtained in the second step after adjusting the molar ratio in the second step, that is, elution by the mineral acid treatment in the first step Which corresponds to about half of the total amount of ferrous ions generated from the ferrous ion added and the ferrous salt added in the second step (the amount converted to ferric hydroxide by oxidation) in a molar ratio. Add iron ions and alkaline substances to adjust pH
It is adjusted to 9 to 11 and stirred under the ferrite forming condition of about 60 to 100 ° C. As the reaction proceeds, the brownish-red precipitate becomes black, and the physical properties of the precipitate change drastically. This black precipitate is mainly ferrite, and its sedimentation, concentration and dehydration properties are dramatically improved as compared with ferric hydroxide. Then, when the coprecipitated product is converted to ferrite, heavy metal ions other than iron in the coprecipitated product are occluded in the ferrite and become chemically stable. Although its chemical structure is unknown, other heavy metal ions are incorporated into the crystal lattice of ferrite and become chemically stable, as in the case of magnetite steel and sand iron in the natural world. It is considered that the occluded heavy metal ions do not elute in water. This is separated together with the acid-insoluble components in the fly ash. On the other hand, the concentration of heavy metal ions remaining on the liquid side after separating ferrite is 10 -1 to 10 -3 ppm unit or less, and if the pH is adjusted as necessary, it can be discharged or reused. As the ferrous iron ion source, ferrous sulfate, ferrous chloride, ferrous nitrate, or pickling waste liquid containing ferrous ions can be used. In this way, according to the invention, it is possible to meet new standards for the elution of heavy metals.
【０００９】[0009]
【比較例１】水分２０重量％を含有する焼却飛灰１Ｋｇ
に、希硫酸７．８リッターを加えてｐＨを１に調整し、
室温で撹拌して焼却飛灰中の酸不溶成分が懸濁している
液を得た。懸濁液中に溶出している重金属類はＺｎ：２
２００ｐｐｍ、Ｐｂ：１５０ｐｐｍ、Ｃｒ：６０ｐｐ
ｍ、Ｃｄ：５０ｐｐｍ、Ａｓ：５０ｐｐｍ及びＦｅ：４
５００ｐｐｍであった。このＦｅ（第１鉄イオン）は鉄
以外の重金属類（Ａｓを含む）の約２倍モルに相当する
（第１工程）。この懸濁液に水酸化ナトリウム水溶液を
加えてｐＨを６〜７の範囲に保ちながら１時間空気を吹
き込み酸化することにより茶褐色の水酸化第２鉄が沈澱
した。この水酸化第２鉄沈澱物中には重金属類の大部分
が共沈していた（鉄／重金属類のモル比が異なる以外は
本発明の第２工程に相当）。この共沈物及び焼却飛灰中
の酸不溶成分が懸濁している液を７０℃に加熱し、第２
工程において存在した鉄イオンの２分の１モル（鉄以外
の重金属類に対しては１倍モル）の硫酸第１鉄を加え更
に水酸化ナトリウム水溶液を加えてｐＨ９〜１１に調整
し約７０℃にて撹拌することにより前記共沈生成物をフ
ェライトとし鉄以外の重金属類イオンを前記フェライト
に吸蔵させ、これを濾過してフェライト及び焼却飛灰中
の酸不溶成分よりなる固形分と濾液とに分離した（第３
工程）。環境庁告示１３号法による固形分の溶出試験及
び濾液中の重金属濃度を測定した結果を表１に示す。固
形分より溶出する重金属及び及び濾液中の重金属類はｐ
ｐｍオーダーで、満足すべき結果は得られなかった。[Comparative Example 1] 1 Kg of fly ash containing 20% by weight of water
Then, 7.8 liters of diluted sulfuric acid is added to adjust the pH to 1, and
The mixture was stirred at room temperature to obtain a liquid in which acid-insoluble components in fly ash were suspended. Heavy metals eluted in the suspension are Zn: 2
200ppm, Pb: 150ppm, Cr: 60pp
m, Cd: 50 ppm, As: 50 ppm and Fe: 4
It was 500 ppm. This Fe (ferrous iron ion) corresponds to about twice the molar amount of heavy metals other than iron (including As) (first step). A brownish ferric hydroxide was precipitated by adding an aqueous solution of sodium hydroxide to this suspension and blowing air for 1 hour while maintaining the pH in the range of 6 to 7 for oxidation. Most of the heavy metals were co-precipitated in this ferric hydroxide precipitate (corresponding to the second step of the present invention except that the molar ratio of iron / heavy metals was different). The coprecipitate and the liquid in which the acid-insoluble components in the incineration fly ash are suspended are heated to 70 ° C.
One half of the iron ions present in the process (1 mol for heavy metals other than iron) ferrous sulfate was added, and a sodium hydroxide aqueous solution was further added to adjust the pH to 9 to 11 to about 70 ° C. By stirring the coprecipitated product with ferrite to occlude heavy metal ions other than iron in the ferrite, and filtering this into a solid and a filtrate consisting of acid-insoluble components in the ferrite and incineration fly ash. Separated (3rd
Process). Table 1 shows the results of the solid content elution test and the heavy metal concentration in the filtrate measured by the Environmental Agency Notification Method 13. Heavy metals eluted from solids and heavy metals in the filtrate are p
Satisfactory results were not obtained on the pm order.
【００１０】[0010]
【比較例２】比較例１の第１工程と同様にして得られた
焼却飛灰の硫酸処理懸濁液に、懸濁液中に溶出している
鉄以外の重金属類に対し２倍モルの硫酸第１鉄を添加し
た。焼却飛灰から溶出した重金属類に対して約２倍モル
の第１鉄イオンと合わせて鉄以外の重金属類の約４倍モ
ルに相当する。この懸濁液に水酸化ナトリウム水溶液を
加えてｐＨを６〜７の範囲に保ちながら１時間空気を吹
き込み酸化することにより茶褐色の水酸化第２鉄が沈澱
した。この水酸化第２鉄沈澱物中には重金属類の大部分
が共沈していた（鉄／重金属類のモル比が異なる以外は
本発明の第２工程に相当）。この共沈物及び焼却飛灰中
の酸不溶成分が懸濁している液を７０℃に加熱し、第２
工程において存在した鉄イオンの２分の１モル（鉄以外
の重金属類に対しては２倍モル）の硫酸第１鉄を加え、
更に水酸化ナトリウム水溶液を加えてｐＨ９〜１１に調
整し約７０℃にて撹拌することにより前記共沈生成物を
フェライトとし鉄以外の重金属類イオンを前記フェライ
トに吸蔵させ、これを濾過してフェライト及び焼却飛灰
中の酸不溶成分よりなる固形分と濾液とに分離した（第
３工程）。環境庁告示１３号法による固形分の溶出試験
及び濾液中の重金属濃度を測定した結果を表１に示す。
固形分より溶出する重金属及び及び濾液中の重金属類は
未だ多く、十分に満足すべき結果は得られなかった。[Comparative Example 2] A sulfuric acid-treated suspension of incineration fly ash obtained in the same manner as in the first step of Comparative Example 1 was used in an amount of twice the molar amount of heavy metals other than iron eluted in the suspension. Ferrous sulfate was added. It corresponds to about 4 times mol of heavy metals other than iron, including about 2 times mol of ferrous ions with respect to heavy metals eluted from incineration fly ash. A brownish ferric hydroxide was precipitated by adding an aqueous solution of sodium hydroxide to this suspension and blowing air for 1 hour while maintaining the pH in the range of 6 to 7 for oxidation. Most of the heavy metals were co-precipitated in this ferric hydroxide precipitate (corresponding to the second step of the present invention except that the molar ratio of iron / heavy metals was different). The coprecipitate and the liquid in which the acid-insoluble components in the incineration fly ash are suspended are heated to 70 ° C.
Add 1/2 mole of iron ions present in the process (2 times mole for heavy metals other than iron) ferrous sulfate,
Further, an aqueous sodium hydroxide solution is added to adjust the pH to 9 to 11 and the mixture is stirred at about 70 ° C. to make the coprecipitated product ferrite and occlude the heavy metal ions other than iron in the ferrite, and to filter the ferrite. And a solid content consisting of an acid-insoluble component in the fly ash and a filtrate were separated (third step). Table 1 shows the results of the solid content elution test and the heavy metal concentration in the filtrate measured by the Environmental Agency Notification Method 13.
The heavy metals eluted from the solid content and the heavy metals in the filtrate were still large in number, and satisfactory results could not be obtained.
【００１１】[0011]
【実施例１】比較例１の第１工程と同様にして得られた
焼却飛灰の硫酸処理懸濁液に、懸濁液中に溶出している
鉄以外の重金属類に対し４倍モルの硫酸第１鉄を添加し
た。焼却飛灰から溶出した重金属類に対して約２倍モル
の第１鉄イオンと合わせて鉄以外の重金属類の約６倍モ
ルに相当する。この懸濁液に水酸化ナトリウム水溶液を
加えてｐＨを６〜７の範囲に保ちながら１時間空気を吹
き込み酸化することにより茶褐色の水酸化第２鉄が沈澱
した。この水酸化第２鉄沈澱物中には重金属類の大部分
が共沈していた（第２工程）。この共沈物及び焼却飛灰
中の酸不溶成分が懸濁している液を７０℃に加熱し、第
２工程において存在した鉄イオンの２分の１モル（鉄以
外の重金属類に対しては３倍モル）の硫酸第１鉄を加え
更に水酸化ナトリウム水溶液を加えてｐＨ９〜１１に調
整し約７０℃にて撹拌することにより前記共沈生成物を
フェライトとし鉄以外の重金属類イオンを前記フェライ
トに吸蔵させ、これを濾過してフェライト及び焼却飛灰
中の酸不溶成分よりなる固形分と濾液とに分離した（第
３工程）。環境庁告示１３号法による固形分の溶出試験
及び濾液中の重金属濃度を測定した結果を表１に示す。
固形分より溶出する重金属及び及び濾液中の重金属類は
著しく減少した。[Example 1] A sulfuric acid-treated suspension of incineration fly ash obtained in the same manner as in the first step of Comparative Example 1 contained 4 times mol of heavy metals other than iron eluted in the suspension. Ferrous sulfate was added. Together with about 2 times the molar amount of ferrous ions with respect to the heavy metals eluted from the incineration fly ash, this corresponds to about 6 times the molar amount of heavy metals other than iron. A brownish ferric hydroxide was precipitated by adding an aqueous solution of sodium hydroxide to this suspension and blowing air for 1 hour while maintaining the pH in the range of 6 to 7 for oxidation. Most of the heavy metals were coprecipitated in the ferric hydroxide precipitate (second step). The coprecipitate and the liquid in which the acid-insoluble components in the incineration fly ash are suspended are heated to 70 ° C., and 1/2 mol of the iron ions present in the second step (for heavy metals other than iron, (3 times mol) ferrous sulfate is further added, and a sodium hydroxide aqueous solution is further added to adjust the pH to 9 to 11, and the mixture is stirred at about 70 ° C. to make the coprecipitated product ferrite and the heavy metal ions other than iron as described above. It was allowed to occlude in ferrite, and this was filtered to separate into a filtrate and a solid content consisting of acid-insoluble components in fly ash (third step). Table 1 shows the results of the solid content elution test and the heavy metal concentration in the filtrate measured by the Environmental Agency Notification Method 13.
Heavy metals eluted from the solid content and heavy metals in the filtrate were significantly reduced.
【００１２】[0012]
【実施例２〜６】実施例１に準じ、表１に示す条件で本
発明を実施した。表１に示すように、いずれも固形分よ
り溶出する重金属及び及び濾液中の重金属類は著しく減
少した。特にヒ素の減少が顕著であった。Examples 2 to 6 The present invention was carried out under the conditions shown in Table 1 according to Example 1. As shown in Table 1, the heavy metals eluted from the solid content and the heavy metals in the filtrate were all significantly reduced. Especially, the decrease of arsenic was remarkable.
【００１３】[0013]
【比較例３〜７】表１に示すように、比較例３は第３工
程のフェライト化をｐＨ８で行なったこと、比較例４は
第３工程のフェライト化をｐＨ１２で行なったこと、比
較例５は第３工程のフェライト化を５０℃で行なったこ
と、比較例６は第３工程で第１鉄イオンを添加しなかっ
たこと（１段法）、比較例７は第１工程で鉱酸を添加し
てｐＨを調整しなかったこと以外は本発明の要件を満た
しているが、いずれも満足すべき結果が得られなかっ
た。[Comparative Examples 3 to 7] As shown in Table 1, Comparative Example 3 performed the third step of ferritization at pH 8, and Comparative Example 4 performed the third step of ferritization at pH 12. No. 5 carried out the ferrite formation in the third step at 50 ° C., Comparative Example 6 did not add ferrous ion in the third step (one step method), Comparative Example 7 contained mineral acid in the first step. Although the requirements of the present invention were satisfied except that the pH was not adjusted by adding, the results were not satisfactory.
【００１４】[0014]
【表１】 [Table 1]
【００１５】[0015]
【比較例８】比較例１の第１工程と同様にして得られた
焼却飛灰の硫酸処理懸濁液から固形分（灰分）を分離し
た重金属類を含む溶液について実施例１と同様な条件で
第２工程以下の処理を行った。結果を表１に示す。灰分
が存在しないと重金属類の除去が不十分であった。[Comparative Example 8] The same conditions as in Example 1 were applied to a solution containing heavy metals in which solids (ash) were separated from a sulfuric acid-treated suspension of incineration fly ash obtained in the same manner as in the first step of Comparative Example 1. Then, the treatment from the second step onward was performed. The results are shown in Table 1. Removal of heavy metals was insufficient when ash was not present.
【００１６】[0016]
【発明の効果】従来適切な処理方法がなかった一般廃棄
物、産業廃棄物、特別管理廃棄物の焼却飛灰中に存在す
る重金属類を不溶化して無害にする。Industrial Applicability The heavy metals present in the incineration fly ash of general waste, industrial waste, and specially controlled waste, for which no appropriate treatment method has hitherto been used, are rendered insoluble by making them insoluble.
フロントページの続き (72)発明者 八木 卓朗 神奈川県横浜市南区別所１−14−１ 日揮 株式会社横浜事業所内 (72)発明者 永野 晴敏 神奈川県横浜市南区別所１−14−１ 日揮 株式会社横浜事業所内Front Page Continuation (72) Inventor Takuro Yagi 1-1-14-1 Minami-Shinkan, Yokohama-shi Kanagawa JGC Co., Ltd.Inside the Yokohama Works (72) Harutoshi Nagano 1-1-14 Minami-Shinkan, Yokohama-shi Kanagawa JGC Stock Company Yokohama office
Claims (4)
酸水溶液を加えｐＨを４以下に調整し重金属類を溶出し
て焼却飛灰中の酸不溶成分が懸濁している液を形成させ
る第１工程、（２）懸濁液中に溶出している第１鉄イオ
ンと鉄以外の重金属類イオンを測定し、必要に応じて第
１鉄塩を添加して懸濁液中の第１鉄イオンと鉄以外の重
金属類イオンとのモル比を６：１〜８０：１に調整し更
にアルカリ物質を加えて中性付近に維持しながら酸化剤
を加えて前記第１鉄イオンを酸化して第２鉄イオンにす
ると共に鉄以外の重金属類イオンを水酸化第２鉄との共
沈生成物として沈澱させる第２工程、及び（３）得られ
た共沈生成物に第２工程におけるモル比調整後存在した
第１鉄イオンに対しモル比で約半量に相当する第１鉄イ
オンを加え更にアルカリ物質を加えてｐＨ９〜１１に調
整し約６０〜１００℃にて撹拌することにより前記共沈
生成物をフェライトとし鉄以外の重金属類イオンを前記
フェライトに吸蔵させ焼却飛灰中の酸不溶成分と共に分
離する第３工程とよりなることを特徴とする重金属類含
有焼却飛灰の処理方法。(1) A liquid in which an acid-insoluble component in incineration fly ash is suspended by eluting heavy metals by adding an aqueous solution of a mineral acid to incineration fly ash containing heavy metals to adjust the pH to 4 or less. First step of forming, (2) measurement of ferrous ions and heavy metal ions other than iron, which are eluted in the suspension, and ferrous salt is added if necessary The molar ratio of ferrous ions to heavy metal ions other than iron is adjusted to 6: 1 to 80: 1, and an alkaline substance is further added to maintain near neutrality and an oxidizing agent is added to the ferrous ions. A second step of oxidizing to ferric ions and precipitating heavy metal ions other than iron as a coprecipitated product with ferric hydroxide, and (3) a second step for the obtained coprecipitated product After adjusting the molar ratio, the ferrous ion, which is about half the molar ratio, was added to the existing ferrous ion. A potassium substance is added to adjust the pH to 9 to 11 and the mixture is stirred at about 60 to 100 ° C. to make the coprecipitated product ferrite and occlude heavy metal ions other than iron in the ferrite to cause acid insoluble components in incineration fly ash. A method for treating incinerated fly ash containing heavy metals, which comprises a third step of separating the ash with a heavy metal.
ル、錫、鉛、アンチモン、カドミウム、クロム、ベリリ
ウム、チタン、マンガン、コバルト、バナジウム、セレ
ン、モリブテン、ウラン、白金、金、銀、水銀、ヒ素の
うちの少なくとも１種である請求項１に記載の重金属類
含有焼却飛灰の処理方法。2. Heavy metals other than iron include copper, zinc, nickel, tin, lead, antimony, cadmium, chromium, beryllium, titanium, manganese, cobalt, vanadium, selenium, molybdenum, uranium, platinum, gold, silver, The method for treating incinerated fly ash containing heavy metals according to claim 1, wherein the method is at least one of mercury and arsenic.
酸が硫酸水溶液である請求項１又は請求項２に記載の重
金属類含有焼却飛灰の処理方法。3. The method for treating heavy metal-containing incinerated fly ash according to claim 1 or 2, wherein the mineral acid added to the heavy metal-containing incinerated fly ash is an aqueous sulfuric acid solution.
る請求項１、請求項２又は請求項３に記載の重金属類含
有焼却飛灰の処理方法。4. The method for treating heavy metal-containing incineration fly ash according to claim 1, 2 or 3, wherein the ferrous ion source is an aqueous ferrous sulfate solution.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7119634A JPH08309310A (en) | 1995-05-18 | 1995-05-18 | Treatment method for incinerated fly ash containing heavy metal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7119634A JPH08309310A (en) | 1995-05-18 | 1995-05-18 | Treatment method for incinerated fly ash containing heavy metal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08309310A true JPH08309310A (en) | 1996-11-26 |
Family
ID=14766309
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7119634A Withdrawn JPH08309310A (en) | 1995-05-18 | 1995-05-18 | Treatment method for incinerated fly ash containing heavy metal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08309310A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005161123A (en) * | 2003-11-28 | 2005-06-23 | Mitsui Mining & Smelting Co Ltd | Method for removing arsenic from soot |
| US20130315804A1 (en) * | 2012-05-22 | 2013-11-28 | Fmc Wyoming Corporation | Fly Ash and Fly Ash Leachate Treatment |
| CN112391534A (en) * | 2020-10-26 | 2021-02-23 | 杭州灰弘环保科技有限公司 | Household garbage incineration fly ash reduction and resource treatment method |
-
1995
- 1995-05-18 JP JP7119634A patent/JPH08309310A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005161123A (en) * | 2003-11-28 | 2005-06-23 | Mitsui Mining & Smelting Co Ltd | Method for removing arsenic from soot |
| US20130315804A1 (en) * | 2012-05-22 | 2013-11-28 | Fmc Wyoming Corporation | Fly Ash and Fly Ash Leachate Treatment |
| CN112391534A (en) * | 2020-10-26 | 2021-02-23 | 杭州灰弘环保科技有限公司 | Household garbage incineration fly ash reduction and resource treatment method |
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