JPH0460712B2 - - Google Patents
Info
- Publication number
- JPH0460712B2 JPH0460712B2 JP59199743A JP19974384A JPH0460712B2 JP H0460712 B2 JPH0460712 B2 JP H0460712B2 JP 59199743 A JP59199743 A JP 59199743A JP 19974384 A JP19974384 A JP 19974384A JP H0460712 B2 JPH0460712 B2 JP H0460712B2
- Authority
- JP
- Japan
- Prior art keywords
- solidifying
- weight
- incinerated ash
- sio
- naoh
- 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.)
- Expired - Lifetime
Links
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 84
- 238000000034 method Methods 0.000 claims description 35
- 239000000463 material Substances 0.000 claims description 22
- 238000006243 chemical reaction Methods 0.000 claims description 21
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 20
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 18
- 239000000203 mixture Substances 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 12
- 239000000377 silicon dioxide Substances 0.000 claims description 9
- 229910052681 coesite Inorganic materials 0.000 claims description 7
- 229910052906 cristobalite Inorganic materials 0.000 claims description 7
- 235000012239 silicon dioxide Nutrition 0.000 claims description 7
- 229910052682 stishovite Inorganic materials 0.000 claims description 7
- 239000000126 substance Substances 0.000 claims description 7
- 229910052905 tridymite Inorganic materials 0.000 claims description 7
- 239000004568 cement Substances 0.000 claims description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 4
- 229910052593 corundum Inorganic materials 0.000 claims description 4
- 229910001845 yogo sapphire Inorganic materials 0.000 claims description 4
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 claims description 2
- 239000004927 clay Substances 0.000 claims description 2
- 239000004575 stone Substances 0.000 claims 1
- 238000001027 hydrothermal synthesis Methods 0.000 description 18
- 238000007711 solidification Methods 0.000 description 16
- 230000008023 solidification Effects 0.000 description 16
- 239000007864 aqueous solution Substances 0.000 description 8
- 239000011734 sodium Substances 0.000 description 8
- 238000002386 leaching Methods 0.000 description 6
- 229910000323 aluminium silicate Inorganic materials 0.000 description 5
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 230000035484 reaction time Effects 0.000 description 5
- 238000003825 pressing Methods 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 239000003513 alkali Substances 0.000 description 3
- 239000010426 asphalt Substances 0.000 description 3
- 238000010828 elution Methods 0.000 description 3
- 238000004898 kneading Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 229910021645 metal ion Inorganic materials 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000002901 radioactive waste Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000021148 sequestering of metal ion Effects 0.000 description 2
- VZSRBBMJRBPUNF-UHFFFAOYSA-N 2-(2,3-dihydro-1H-inden-2-ylamino)-N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]pyrimidine-5-carboxamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C(=O)NCCC(N1CC2=C(CC1)NN=N2)=O VZSRBBMJRBPUNF-UHFFFAOYSA-N 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000012958 reprocessing Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Landscapes
- Curing Cements, Concrete, And Artificial Stone (AREA)
- Processing Of Solid Wastes (AREA)
Description
［産業上の利用分野］
本発明は焼却灰の固化方法に係り、特に焼却灰
にNaOHを加えて水熱反応させ固化させるよう
にした焼却灰の固化方法に関するものである。
［従来の技術］
焼却灰の中には種々の金属が含まれており、そ
のまま埋め立て処分或いは海洋投棄処分を行なつ
た場合、焼却灰中からの金属の溶出が問題とな
る。特に放射性廃棄物の焼却灰に関しては、放射
能の溶出及び保管時の安全性の面から焼却灰の固
化プロセスが必要となる。
従来の焼却灰の固化方法としては、セメント固
化法、アスフアルト固化法があるが、固化剤に対
する焼却灰の含有率が少ないため、廃棄物の量が
多くなつてしまう。またアスフアルトについて
は、可燃性であることから、固化物の防火対策が
必要であり、また固化体自体の強度も小さい。
放射性廃棄物の固化方法としては、プラスチツ
ク法や熔融固化法があるが、固化剤或いは固化容
器が高価であり、ランニングコストが高くつき、
設備も大型となる。
［発明が解決しようとする問題点］
上述の通り、セメント固化法、アスフアルト固
化法、プラスチツク固化法、熔融固化法等の従来
の固化法には、固化体の体積が著しく増加する、
固化体が可燃性を有し強度が小さい、高価であ
る、大型の設備を要する等の問題があつた。
［問題点を解決するための手段］
本発明は、SiO2及びAl2O3を含む焼却灰をセメ
ントを用いることなく固化させるために、焼却灰
中に含まれるSiO2を利用し、これにNaOHを添
加して水熱反応させて焼却灰を固化させるように
したものであり、
SiO2及びAl2O3を含む焼却灰に、NaOH、又は
NaOHとSiO2含有物質を、添加後の混合物中の
含有率が、
SiO2 25〜95重量％、
Na2Ｏ ２〜10重量％、
Al2O3３重量％以上でかつモル％で、SiO2含有
率よりも少ない、
となるように添加すると共に、水を混合物100重
量部に対して５〜20重量部添加して混練し、この
混練物を圧力70Kg／cm2以上、温度150℃以上の加
熱加圧状態に保持して固化させることを特徴とす
る焼却灰の固化方法、
を要旨とする。
以下本発明について詳細に説明する。
本発明において固化処理対象とする焼却灰は、
SiO2及びAl2O3を含むものであり、都市ゴミ焼却
灰や一般事業所排出ゴミの焼却灰あるいは原子力
施設（原子力発電所、再処理工場、研究所等）か
ら排出されるゴミの焼却灰等が該当する。
本発明においては、このような焼却灰に、
NaOHと所望により更にSiO2含有物質を添加し、
SiO225〜95％、Na2O2〜10％、Al2O3３％以上な
る組成を有する混合物とする。また、Al2O3含有
率（モル％）は、SiO2の含有率（モル％）より
も少なくなるようにする。
（なお本明細書において組成を表す％は、特に
断らない限り、重量％を表す。）
一般に焼却灰におけるNa2Ｏの含有率は１％前
後もしくはそれよりも低いので、本発明において
はNaOHの添加は必須である。また通常の焼却
灰はSiO2、Al2O3の含有率は上記混合物の範囲に
入つていることが多いので、SiO2の添加は必須
のものではないが、上記範囲からはずれる場合に
SiO2含有物質を添加し調整する。
SiO2含有物質としては、珪石粉末や白土粉末
等が好適であるが、SiO2を多く含む焼却灰を用
いても良い。
本発明においては、次に述べるように、上記混
合物に水を添加するので、NaOHは、水酸化ナ
トリウム水溶液の形として添加するのが便利であ
る。
本発明は、上記混合物に対して水を５〜20重量
部の割合で添加する。この水の添加は上述のよう
に水酸化ナトリウム水溶液の形として添加するの
が良いのであるが、水単独で添加しても良い。
上記混合物に水を添加して混練した後、この混
練物を圧力70Kg／cm2以上、温度150℃以上の加熱
加圧状態に保持して水熱反応を行なわせ混合物の
固化を行なわせる。即ち本発明は、この水熱合成
反応により、少なくとも部分的に水和した含アル
カリアルミノシリケートの３次元骨格構造（ネツ
トワーク）を形成し、これにより焼却灰を固化さ
せると共に、焼却灰中に含まれる各種金属（とり
わけ重金属）をこのネツトワーク中に封じ込める
ようにしたものである。
次にSiO2、Al2O3及びNa2Ｏの含有率の範囲に
ついて説明する。
SiO2は、前述の含アルカリアルミノシリケー
トのネツトワークを作る酸化物でり、その含有率
が25％よりも少ないと、ネツトワークが十分に形
成されず、固化体の強度も不十分で脆いものとな
る。また、SiO2の上限は特に規定されるもので
はないが、Na2Ｏ、Al2O3の下限値が２％、３％
であるので、本発明においては、SiO2含有率を
95％以下とする。なお、特に好ましい範囲は30〜
60％である。
Al2O3は、それ単独ではネツトワークを構成す
ることはできないが、ネツクワーク中のSiO2の
一部と置き替わることによりネツトワークを構成
する。そしてネツクワーク中でSiと入れ替わつた
Alは負電荷を有し、プラスの電荷を有する金属
イオンを保持するようになる。Al2O3が３重量％
よりも少ないとネツトワークの金属イオン封鎖
（封じ込め）機能が低下する。またAl2O3含有率
がモル％でSiO2よりも多いと、ネツトワークが
十分には成長しないようになる。
Na2Ｏは水熱反応中にSiO2やAl2O3と反応し、
アルミノシリケートのネツトワーク構成反応や水
和反応を促進する。Na2Ｏが２％よりも少ないと
この反応促進が不十分となり、逆に10％より多い
とアルミノシリケートのネツトワークが切れ、固
化体の強度が低下すると共に、ネツトワークの金
属イオン封鎖機能が低下する。
なお、本発明において、混合物中における
NaOHは、Na2ＯとH2Ｏとに分けてNa2Ｏ含有率
を計算する。この場合、NaOHに由来するH2Ｏ
は添加する水分と合算するものとし、焼却灰重量
には含めない。
上記混合物に添加する水の量は、混合物100重
量部に対して５〜20重量部の範囲である。水の添
加量が５重量部よりも少ないと水熱反応が十分に
は進行せず、逆に20重量部を超える場合には、固
化体の気孔が多量化かつ大径化し、強度が低下す
ると共に、固化体から金属が溶出し易くなる。
本発明において、水熱反応の圧力は70Kg／cm2以
上である。圧力の上限は、実用的には500Kg／cm2
程度である。なお圧力は、当然ながらその反応温
度における水の蒸気圧よりも高い圧力とし、水熱
状態になるようにする。
水熱反応の温度は、150℃よりも低いと、固化
反応が進行せず、極めて強度の低い固化体しか得
られない。特に好ましい温度は200〜350℃以上で
ある。
水熱反応時間は、５分から１時間程度で十分で
ある。水熱反応の圧力、温度が低い場合にはこの
反応時間は長目になり、逆に圧力、温度を高くす
れば反応時間は短くて足りる。なお本発明者等の
研究によれば、上記圧力及び温度の範囲におい
て、なるべく低い圧力及び温度の条件下に長い時
間保持する方が、得られる固化体の強度が高いこ
とが認められた。
なお本発明においては、前述のSiO2、Al2O3及
びNa2Ｏの他にFe2O3、Cr2O3、MgO、CaO、
TiO2、K2Ｏ等の金属酸化物を含んでも良い。こ
れらの金属酸化物は、合量で40％位までならば強
度にそれほどの影響を与えることなく含むことが
できる。またSO4 --、Cl-等の陰イオンも合計で
20％程度まで含んでも良い。特にSO4 --は、石膏
（CaSO4）として存在する場合には、焼却灰の固
化反応を促進する。
本発明の方法において、水熱反応を行なわせる
には、筒体の一端又は両端に圧縮ピストンを嵌装
させて筒体中央に反応充填室を形成した装置を用
いるのが便利である。即ち、水を添加して混練し
た混合物をこの反応充填室内に充填し、圧縮ピス
トンで充填物を圧縮しながら加熱して水熱反応を
行なわせるのである。
第１図はこのような反応装置を用いた場合の本
発明の固化方法の手順の一例を示すブロツク図で
ある。
即ち、図示の如く、まず焼却灰を秤量し、これ
にNaOH水溶液を添加して混練した後、反応装
置に充填し、加圧しながら加熱し、水熱反応を行
なわせる。
なお秤量に先立つて、焼却灰に含まれるボル
ト、ワイヤあるいは焼結した焼却灰の粗大粒子を
取り除く等の前処理を施しておけば、後工程が容
易になる。
所定時間経過後、反応装置の温度を下げ固化体
を取り出す。
本発明方法においては、混練物を反応装置に充
填するに際して、混練物を２又はそれ以上に区分
けし、一区分け量を反応装置に充填する毎にプレ
ス（以下、仮プレスということがある。）するよ
うにするのが好ましい。このように仮プレスすれ
ば、反応装置内に充填された一区分け量の混練物
が直ちに圧縮されてその体積が小さくなるので、
反応装置内に多量の混練物を充填することが可能
となり、反応装置の小容量化も可能となる。この
仮プレス圧は、固化反応時の圧力よりも小さくて
良く、例えば固化反応時の圧力の１／10程度で良
い。なお、区分けした混練物を全て反応装置内に
充填した後のプレスは、このような軽度の仮プレ
スを行なうことなく、固化反応時の圧力でプレス
し、反応を開始すれば足りる。
而して、本発明の方法においては、固化反応を
行なつているときに、被処理焼却灰が加熱加圧状
態にあれば良く、所定の反応圧力への昇圧と、所
定の反応温度への昇温は、これらのいずれかを先
行させても良く、これらを同時に行なつても良
い。
第１図のプロセスは本発明方法の一例を示すも
のであるから、本発明方法はこの第１図のプロセ
スに限定されるものではない。
［作用］
焼却灰にNaOH及び所望によりSiO2を添加し、
水を加えて混練した後、これを水熱反応させるこ
とにより、少なくとも部分的に水和した含アルカ
リアルミノシリケートの３次元ネツトワークを有
する固化体が得られる。この固化体中には金属が
保持され、かつ固化体の強度も高く、金属イオン
の溶出等が極めて少ない。また焼却灰の体積も著
しく小さくなる。
［実施例］
以下に本発明を実施例を挙げて更に具体的に説
明するが、本発明はその要旨を超えない限り以下
の実施例に限定されるものではない。
実施例 １
表１に示す組成を有する焼却灰を、１Kg秤量
し、この焼却灰に表２で示す濃度及び量の水酸化
ナトリウム水溶液を添加し、混練した後、506
Kg／cm2、300℃に20分間保持し水熱反応させ、固
化体とした。
得られた固化体を70℃の蒸留水中に24時間浸漬
した場合の浸出率を測定した。その結果を表２に
示す。
実施例 ２
NaOH水溶液の濃度及び添加量、ならびに反
応温度を表３に示す如く変えたこと以外は実施例
１と同様にして固化体を得た。この固化体の浸出
率を実施例１と同様にして測定した。その結果を
表３に示す。
実施例 ３
NaOH水溶液の濃度及び添加量、ならびに圧
力を表４に示す如く変えたこと以外は、実施例１
と同様にして、固化体を得た。得られた固化体の
浸出率の測定結果を表４に示す。
実施例 ４
NaOH水溶液の濃度及び添加量、ならびに反
応時間を表５に示す如く変えたこと以外は、実施
例１と同様にして固化体を得た。この固化体の浸
出率を表５に示す。
実施例 ５
10NのNaOH水溶液を150c.c.添加すると共に、
反応温度を150〜350℃の範囲で変えたこと以外
は、実施例１と同様にして固化体を得た。この固
化体の圧縮強度の測定結果を第２図に示す。
実施例 ６
10NのNaOH水溶液を150c.c.添加し、水熱反応
時の圧力を100〜500Kg／cm2の間で変えたこと以外
は実施例１と同様にして固化体を得、この固化体
の圧縮強度を測定した。その結果を第３図に示
す。
実施例 ７
8NのNaOH水溶液を用いたこと以外は実施例
６と同様にして固化体を得、その圧縮強度を測定
した。その結果を第３図にあわせて示す。
実施例 ８
10NのNaOH水溶液を150c.c.添加し、水熱反応
時の圧力を500Kg／cm2とし、反応時間を20分から
60分の間で変えたこと以外は実施例１と同様にし
て固化体を得、その圧縮強度を測定した。その結
果を第４図に示す。
実施例 ９
8NのNaOH水溶液を用いたこと以外は実施例
８と同様の試験を行なつた。圧縮強度の測定結果
を第４図に示す。
実施例 10
NaOHの濃度と添加量を種々変えて、実施例
１と同様にして固化体を得、その圧縮強度を測定
した。その結果を第５図に示す。
上記各実施例より、本発明の方法によれば、焼
却灰が、高強度でかつ浸出率の小さい固化体とな
ることが明らかである。また固化体の体積は焼却
灰の体積の６分の１程度になることが認められ
た。
[Industrial Application Field] The present invention relates to a method for solidifying incinerated ash, and more particularly, to a method for solidifying incinerated ash in which NaOH is added to incinerated ash and solidified by a hydrothermal reaction. [Prior Art] Incineration ash contains various metals, and if the incineration ash is directly disposed of in a landfill or disposed of in the ocean, metals leaching out of the incineration ash becomes a problem. In particular, regarding the incineration ash of radioactive waste, a solidification process is required for the incineration ash in terms of radioactivity elution and safety during storage. Conventional methods for solidifying incinerated ash include a cement solidifying method and an asphalt solidifying method, but since the content of incinerated ash to the solidifying agent is low, the amount of waste increases. Furthermore, since asphalt is flammable, fire prevention measures are required for the solidified material, and the strength of the solidified material itself is low. Methods for solidifying radioactive waste include the plastic method and the melt solidification method, but solidification agents and solidification containers are expensive, and running costs are high.
The equipment will also be large. [Problems to be solved by the invention] As mentioned above, conventional solidification methods such as cement solidification method, asphalt solidification method, plastic solidification method, and melt solidification method have problems in that the volume of the solidified body increases significantly.
There were problems such as the solidified material was flammable, had low strength, was expensive, and required large equipment. [Means for solving the problem] The present invention utilizes SiO 2 contained in the incinerated ash and solidifies the incinerated ash containing SiO 2 and Al 2 O 3 without using cement. The incineration ash is solidified by adding NaOH and causing a hydrothermal reaction.The incineration ash containing SiO2 and Al2O3 is mixed with NaOH or
The content of NaOH and SiO2- containing substances in the mixture after addition is 25 to 95% by weight of SiO2 , 2 to 10% by weight of Na2O , 3 % or more by weight of Al2O3 , and mol% of SiO2. At the same time, 5 to 20 parts by weight of water is added to 100 parts by weight of the mixture and kneaded, and the kneaded product is heated at a pressure of 70 kg/cm 2 or more and a temperature of 150°C or more. A method for solidifying incinerated ash characterized by solidifying it by holding it in a heated and pressurized state. The present invention will be explained in detail below. The incineration ash to be solidified in the present invention is
Contains SiO 2 and Al 2 O 3 , and is incinerated ash of municipal waste, incinerated ash of general business waste, or incinerated ash of waste discharged from nuclear facilities (nuclear power plants, reprocessing plants, research institutes, etc.) etc. are applicable. In the present invention, such incineration ash is
Add NaOH and optionally further SiO2- containing substances,
The mixture has a composition of 25 to 95% SiO2 , 10% to Na2O2 , and 3 % or more of Al2O3 . Further, the Al 2 O 3 content (mol %) is set to be lower than the SiO 2 content (mol %). (In this specification, % indicating the composition indicates weight % unless otherwise specified.) Generally, the content of Na 2 O in incinerated ash is around 1% or lower, so in the present invention, the content of NaOH is Addition is essential. In addition, the content of SiO 2 and Al 2 O 3 in ordinary incineration ash is often within the range of the above mixture, so it is not essential to add SiO 2 , but if it falls outside the above range,
Add and adjust SiO2 -containing substances. As the SiO 2 -containing substance, silica powder, clay powder, etc. are suitable, but incineration ash containing a large amount of SiO 2 may also be used. In the present invention, as water is added to the above mixture as described below, it is convenient to add NaOH in the form of an aqueous sodium hydroxide solution. In the present invention, water is added to the above mixture in an amount of 5 to 20 parts by weight. Although this water is preferably added in the form of an aqueous sodium hydroxide solution as described above, water alone may be added. After water is added to the above mixture and kneaded, the kneaded product is maintained under heating and pressure at a pressure of 70 kg/cm 2 or more and a temperature of 150° C. or more to carry out a hydrothermal reaction and solidify the mixture. That is, in the present invention, a three-dimensional skeletal structure (network) of at least partially hydrated alkali-containing aluminosilicate is formed through this hydrothermal synthesis reaction, thereby solidifying the incinerated ash and reducing the amount contained in the incinerated ash. This network is designed to confine various metals (particularly heavy metals) that are produced in the network. Next, the content ranges of SiO 2 , Al 2 O 3 and Na 2 O will be explained. SiO 2 is an oxide that forms the network of the alkali-containing aluminosilicate mentioned above, and if its content is less than 25%, the network will not be sufficiently formed and the solidified material will have insufficient strength and become brittle. becomes. In addition, the upper limit of SiO 2 is not particularly specified, but the lower limit of Na 2 O, Al 2 O 3 is 2%, 3%.
Therefore, in the present invention, the SiO 2 content is
95% or less. Note that a particularly preferable range is 30 to
It is 60%. Although Al 2 O 3 cannot form a network by itself, it forms a network by replacing a part of SiO 2 in the network. Then it switched places with Si in the network.
Al has a negative charge and comes to hold positively charged metal ions. Al 2 O 3 is 3% by weight
If the amount is less than , the metal ion sequestration (containment) function of the network will be reduced. Furthermore, if the Al 2 O 3 content is greater than SiO 2 in terms of mole %, the network will not grow sufficiently. Na 2 O reacts with SiO 2 and Al 2 O 3 during the hydrothermal reaction,
Promotes network formation reactions and hydration reactions of aluminosilicate. If Na 2 O is less than 2%, this reaction promotion will be insufficient, and if it is more than 10%, the aluminosilicate network will break, the strength of the solidified product will decrease, and the metal ion sequestration function of the network will be impaired. descend. In addition, in the present invention, in the mixture
NaOH is divided into Na 2 O and H 2 O to calculate the Na 2 O content. In this case, H 2 O derived from NaOH
shall be added to the added moisture and not included in the weight of incinerated ash. The amount of water added to the mixture ranges from 5 to 20 parts by weight per 100 parts by weight of the mixture. If the amount of water added is less than 5 parts by weight, the hydrothermal reaction will not proceed sufficiently, and if it exceeds 20 parts by weight, the pores of the solidified material will increase in number and size, resulting in a decrease in strength. At the same time, the metal becomes easier to dissolve from the solidified body. In the present invention, the pressure of the hydrothermal reaction is 70 Kg/cm 2 or more. The upper limit of pressure is practically 500Kg/cm 2
That's about it. Note that the pressure is naturally higher than the vapor pressure of water at the reaction temperature, so that a hydrothermal state is achieved. If the temperature of the hydrothermal reaction is lower than 150°C, the solidification reaction will not proceed and only a solidified product with extremely low strength will be obtained. A particularly preferred temperature is 200 to 350°C or higher. A hydrothermal reaction time of about 5 minutes to 1 hour is sufficient. If the pressure and temperature of the hydrothermal reaction are low, the reaction time will be long; on the other hand, if the pressure and temperature are high, the reaction time will be short. According to research conducted by the present inventors, it has been found that within the above pressure and temperature ranges, the strength of the obtained solidified product is higher when the material is maintained for a longer period of time under the lowest possible pressure and temperature conditions. In addition, in the present invention, in addition to the above-mentioned SiO 2 , Al 2 O 3 and Na 2 O, Fe 2 O 3 , Cr 2 O 3 , MgO, CaO,
It may also contain metal oxides such as TiO 2 and K 2 O. These metal oxides can be contained in a total amount of up to about 40% without significantly affecting the strength. In addition, anions such as SO 4 -- and Cl - are also
It may be included up to about 20%. In particular, SO 4 -- , when present as gypsum (CaSO 4 ), accelerates the solidification reaction of incineration ash. In the method of the present invention, in order to carry out the hydrothermal reaction, it is convenient to use an apparatus in which a compression piston is fitted to one or both ends of a cylindrical body and a reaction filling chamber is formed in the center of the cylindrical body. That is, a mixture obtained by adding water and kneading is filled into this reaction filling chamber, and the filling is heated while being compressed by a compression piston to cause a hydrothermal reaction. FIG. 1 is a block diagram showing an example of the procedure of the solidification method of the present invention when such a reaction apparatus is used. That is, as shown in the figure, incineration ash is first weighed, an aqueous NaOH solution is added thereto and kneaded, and then the mixture is filled into a reactor and heated under pressure to carry out a hydrothermal reaction. Note that, prior to weighing, pretreatment such as removing bolts, wires, or coarse particles of sintered incineration ash contained in the incineration ash is performed to facilitate the subsequent process. After a predetermined period of time has elapsed, the temperature of the reactor is lowered and the solidified material is taken out. In the method of the present invention, when charging the kneaded material into the reaction apparatus, the kneaded material is divided into two or more parts, and pressed (hereinafter sometimes referred to as temporary pressing) each time one division is filled into the reaction apparatus. It is preferable to do so. By performing temporary pressing in this way, the kneaded material in one section filled in the reactor will be compressed immediately and its volume will be reduced.
It becomes possible to fill a large amount of kneaded material into the reactor, and it also becomes possible to reduce the capacity of the reactor. This temporary pressing pressure may be lower than the pressure during the solidification reaction, for example, about 1/10 of the pressure during the solidification reaction. Note that after all of the divided kneaded materials have been filled into the reaction apparatus, it is sufficient to press at the pressure used for the solidification reaction and start the reaction without performing such a mild temporary pressing. Therefore, in the method of the present invention, it is sufficient that the incinerated ash to be treated is in a heated and pressurized state during the solidification reaction, and the pressure is increased to a predetermined reaction pressure and the incineration ash is raised to a predetermined reaction temperature. The temperature may be increased in advance of any of these steps, or may be performed simultaneously. Since the process shown in FIG. 1 shows an example of the method of the present invention, the method of the present invention is not limited to the process shown in FIG. [Function] Add NaOH and SiO 2 as desired to the incinerated ash,
After adding water and kneading, this is subjected to a hydrothermal reaction to obtain a solidified body having a three-dimensional network of at least partially hydrated alkali-containing aluminosilicate. The metal is retained in this solidified body, and the strength of the solidified body is also high, with extremely little elution of metal ions. The volume of incinerated ash is also significantly reduced. [Examples] The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. Example 1 1 kg of incinerated ash having the composition shown in Table 1 was weighed, and an aqueous sodium hydroxide solution with a concentration and amount shown in Table 2 was added to this incinerated ash and kneaded.
Kg/cm 2 and held at 300° C. for 20 minutes to cause a hydrothermal reaction, resulting in a solidified product. The leaching rate was measured when the obtained solidified body was immersed in distilled water at 70°C for 24 hours. The results are shown in Table 2. Example 2 A solidified body was obtained in the same manner as in Example 1, except that the concentration and amount of the NaOH aqueous solution added and the reaction temperature were changed as shown in Table 3. The leaching rate of this solidified material was measured in the same manner as in Example 1. The results are shown in Table 3. Example 3 Example 1 except that the concentration and amount of NaOH aqueous solution added and the pressure were changed as shown in Table 4.
A solidified body was obtained in the same manner as above. Table 4 shows the measurement results of the leaching rate of the obtained solidified material. Example 4 A solidified body was obtained in the same manner as in Example 1, except that the concentration and amount of the NaOH aqueous solution added and the reaction time were changed as shown in Table 5. Table 5 shows the leaching rate of this solidified material. Example 5 While adding 150 c.c. of 10N NaOH aqueous solution,
A solidified product was obtained in the same manner as in Example 1, except that the reaction temperature was changed in the range of 150 to 350°C. The results of measuring the compressive strength of this solidified body are shown in FIG. Example 6 A solidified product was obtained in the same manner as in Example 1, except that 150 c.c. of 10N NaOH aqueous solution was added and the pressure during the hydrothermal reaction was varied between 100 and 500 Kg/cm 2 . The compressive strength of the body was measured. The results are shown in FIG. Example 7 A solidified body was obtained in the same manner as in Example 6 except that an 8N NaOH aqueous solution was used, and its compressive strength was measured. The results are also shown in FIG. Example 8 Add 150 c.c. of 10N NaOH aqueous solution, set the pressure during hydrothermal reaction to 500 Kg/cm 2 , and set the reaction time to 20 minutes.
A solidified body was obtained in the same manner as in Example 1 except that the time period was changed for 60 minutes, and its compressive strength was measured. The results are shown in FIG. Example 9 A test similar to Example 8 was conducted except that an 8N NaOH aqueous solution was used. The measurement results of compressive strength are shown in FIG. Example 10 Solidified bodies were obtained in the same manner as in Example 1 by varying the concentration and amount of NaOH added, and their compressive strengths were measured. The results are shown in FIG. From the above examples, it is clear that according to the method of the present invention, incineration ash becomes a solidified body with high strength and low leaching rate. It was also observed that the volume of the solidified material was approximately one-sixth of the volume of the incinerated ash.
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】
［効果］
以上の通り本発明は、焼却灰をセメントを用い
ることなく固化させる方法であつて、焼却灰に
NaOHと所望によりSiO2含有物質を添加し、水
を添加して混練した後、水熱反応させて固化させ
るようにしたものであり、得られる固化体の強度
が高く、金属イオン等の溶出も極めて少ない。ま
た、固化体の体積も、元の焼却灰の体積の６分の
１以下程度の小さなものとなる。更に、加熱、加
圧装置も通常のもので足り、その他の特別の装置
を用いる必要がないと共に、添加剤も安価である
のでランニングコストも低い。[Table] [Effects] As described above, the present invention is a method for solidifying incinerated ash without using cement.
After adding NaOH and optionally a SiO2- containing substance, adding water and kneading, the product is solidified by a hydrothermal reaction, and the resulting solidified product has high strength and prevents the elution of metal ions, etc. Very few. Moreover, the volume of the solidified material is also small, about one-sixth or less of the volume of the original incinerated ash. Further, ordinary heating and pressurizing equipment is sufficient, there is no need to use other special equipment, and the additives are inexpensive, so the running cost is low.
第１図は本発明の実施の一手順を示すブロツク
図、第２図〜第５図の各図は実施例における測定
結果を示すグラフである。
FIG. 1 is a block diagram showing one procedure for implementing the present invention, and each of FIGS. 2 to 5 is a graph showing measurement results in the example.
Claims (1)
いることなく固化させる方法であつて、該焼却灰
に、NaOH、又はNaOHとSiO2含有物質を、添
加後の混合物中の含有率が、 SiO2 25〜95重量％、 Na2Ｏ ２〜10重量％、 Al2O3３重量％でかつモル％で、SiO2含有率よ
りも少ない、 となるように添加すると共に、水を混合物100重
量部に対して５〜20重量部添加して混練し、この
混練物を圧力70Kg／cm2以上、温度150℃以上の加
熱加圧状態に保持して固化させることを特徴とす
る焼却灰の固化方法。 ２ NaOH及び水を、NaOH水溶液として添加
することを特徴とする特許請求の範囲第１項に記
載の焼却灰の固化方法。 ３ SiO2含有物質は珪石又は白土であることを
特徴とする特許請求の範囲第１項又は第２項に記
載の焼却灰の固化方法。 ４ 前記混練物を加圧反応装置に充填し、該装置
中にて固化させる方法であつて、該装置に混練物
を充填するに際し、混練物を２以上に区分けし、
一区分け量を容器に充填する毎に装置内の混練物
をプレスすることを特徴とする特許請求の範囲第
１項ないし第３項のいずれか１項に記載の焼却灰
の固化方法。[Claims] 1. A method for solidifying incinerated ash containing SiO 2 and Al 2 O 3 without using cement, the method comprising: adding NaOH or a substance containing NaOH and SiO 2 to the incinerated ash; Added so that the content in the mixture is 25 to 95% by weight of SiO2 , 2 to 10% by weight of Na2O , 3 % by weight of Al2O3 , and is less than the SiO2 content in mol%. At the same time, add 5 to 20 parts by weight of water to 100 parts by weight of the mixture, knead it, and solidify this kneaded product by holding it in a heated and pressurized state at a pressure of 70 kg/cm 2 or more and a temperature of 150°C or more. A method for solidifying incineration ash characterized by: 2. The method for solidifying incinerated ash according to claim 1, characterized in that NaOH and water are added as an aqueous NaOH solution. 3. The method for solidifying incineration ash according to claim 1 or 2, wherein the SiO 2 -containing substance is silica stone or white clay. 4. A method of filling the kneaded material into a pressurized reaction device and solidifying the kneaded material in the device, which method includes dividing the kneaded material into two or more parts when filling the kneaded material into the device,
A method for solidifying incinerated ash according to any one of claims 1 to 3, characterized in that the kneaded material in the device is pressed each time one division is filled into a container.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59199743A JPS6178483A (en) | 1984-09-25 | 1984-09-25 | Solidification of incineration ash |
| US06/764,686 US4661291A (en) | 1984-09-25 | 1985-08-09 | Method for fixation of incinerator ash or iodine sorbent |
| GB8521297A GB2165828B (en) | 1984-09-25 | 1985-08-27 | Method for fixation of waste comprising incinerator ash or iodine |
| DE19853531607 DE3531607A1 (en) | 1984-09-25 | 1985-09-04 | METHOD FOR FIXING THE INCINERATOR ASH OR IODINE |
| FR8514124A FR2570865A1 (en) | 1984-09-25 | 1985-09-24 | METHOD FOR FIXING A SORBENT FOR AN INCIDENTER OR RADIOACTIVE IODE BY HYDROTHERMAL REACTION |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59199743A JPS6178483A (en) | 1984-09-25 | 1984-09-25 | Solidification of incineration ash |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6178483A JPS6178483A (en) | 1986-04-22 |
| JPH0460712B2 true JPH0460712B2 (en) | 1992-09-28 |
Family
ID=16412891
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59199743A Granted JPS6178483A (en) | 1984-09-25 | 1984-09-25 | Solidification of incineration ash |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6178483A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2734633B2 (en) * | 1989-05-29 | 1998-04-02 | 三井造船株式会社 | Solidification method of incineration ash |
| JPH05249294A (en) * | 1992-03-03 | 1993-09-28 | Nuclear Fuel Ind Ltd | Method of solidifying and disposing of radioactive contaminant |
| JP4573174B2 (en) * | 2005-08-04 | 2010-11-04 | 地方独立行政法人 東京都立産業技術研究センター | Radioactive waste treatment method and sintered body thereof |
| JP4794372B2 (en) * | 2006-06-23 | 2011-10-19 | 株式会社ナトー研究所 | Phosphorus-containing incinerated ash reforming method and pollution-free phosphorus-containing recycling material |
| JP5410108B2 (en) * | 2008-02-04 | 2014-02-05 | 一般財団法人電力中央研究所 | Method for producing zeolite-containing cured body |
| JP6247465B2 (en) * | 2013-07-08 | 2017-12-13 | 株式会社東芝 | Radioactive waste solidification device, solidification method for solidified radioactive waste, and method for producing solidified solid waste |
| JP6871078B2 (en) * | 2017-06-16 | 2021-05-12 | 東芝エネルギーシステムズ株式会社 | Compression molding method and compression molding equipment for radioactive waste |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5849319A (en) * | 1981-03-18 | 1983-03-23 | マツクス−プランク・ゲゼルシヤフト・ズル・フオ−ルデルング・デル・ヴイ−ゼンズシヤフテン・イ−・ブイ | Mitodiene and isolation |
| JPS59116100A (en) * | 1982-12-23 | 1984-07-04 | 株式会社新来島どっく | Method of sealing radioactive waste by artificial |
-
1984
- 1984-09-25 JP JP59199743A patent/JPS6178483A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5849319A (en) * | 1981-03-18 | 1983-03-23 | マツクス−プランク・ゲゼルシヤフト・ズル・フオ−ルデルング・デル・ヴイ−ゼンズシヤフテン・イ−・ブイ | Mitodiene and isolation |
| JPS59116100A (en) * | 1982-12-23 | 1984-07-04 | 株式会社新来島どっく | Method of sealing radioactive waste by artificial |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6178483A (en) | 1986-04-22 |
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