JP3598324B2 - Method and apparatus for recovering zinc and iron in acid waste liquid as precipitate - Google Patents
Method and apparatus for recovering zinc and iron in acid waste liquid as precipitate Download PDFInfo
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- JP3598324B2 JP3598324B2 JP2001055151A JP2001055151A JP3598324B2 JP 3598324 B2 JP3598324 B2 JP 3598324B2 JP 2001055151 A JP2001055151 A JP 2001055151A JP 2001055151 A JP2001055151 A JP 2001055151A JP 3598324 B2 JP3598324 B2 JP 3598324B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、溶融亜鉛廃液を処理するための方法及びその装置に関するものである。
【０００２】
【従来の技術】
溶融亜鉛メッキは施工単価が安く、塗装以上の防蝕耐久性能を持っているので様々な鋼構造物に広く採用されている。亜鉛溶融メッキの工程では種々の酸廃液が排出されるが、特に鉄鋼製品を溶融亜鉛メッキする際に発生する不良品のメッキ層を溶解した際に発生する亜鉛及び鉄を含有する塩酸廃液や硫酸廃液が、中和法以外に有効な処理方法がなく、問題である。
酸廃液をアルカリで中和すると、大量のアルカリが消費されただけでなく、中和の結果、大量の水酸化物のスラッジが形成される。このスラッジは、鉄と亜鉛が混在することから、水分と分離しても有効活用することができず、このため大量のスラッジを投棄しなければならないという問題がある。
【０００３】
【発明が解決しようとする課題】
本発明は、溶融亜鉛メッキ工程で排出される亜鉛及び鉄を含む酸廃液を効率よくかつ低められたスラッジ発生量で処理するための方法及び装置を提供することをその課題とする。
【０００４】
【課題を解決するための手段】
本発明者らは、前記課題を解決すべく鋭意研究を重ねた結果、本発明を完成するに至った。
即ち、本発明によれば、溶融亜鉛メッキ工程で排出される亜鉛及び鉄を含む酸廃液を被処理液として処理する方法において、該被処理液を、ｐＨ９以上で５０℃以上の水酸化カルシウム懸濁液に滴下混合して、５０℃以上の温度及び６〜１１のｐＨを有する混合液を形成することにより、必要に応じて酸化剤を添加して、該溶存亜鉛イオンと鉄イオンを難溶性物質として沈殿させ、それを回収することを特徴とする溶融亜鉛メッキ工程で排出される亜鉛及び鉄を含む酸廃液から酸化亜鉛を回収する方法が提供される。
さらに、本発明によれば、上記の溶融亜鉛メッキ工程で排出される亜鉛及び鉄を含む酸廃液を被処理液として処理する方法に用いられる装置であって、溶融亜鉛メッキ工程で排出される亜鉛及び鉄を含む酸廃液用原水槽１と、水酸化カルシウム懸濁液を貯蔵し供給するユニット２と、温水を供給するユニット３と、亜鉛及び鉄を含む酸廃液と水酸化カルシウム懸濁液を混合する反応槽４と、酸化剤を添加するユニット５と、凝集剤を添加するユニット６と、凝集槽７と、凝集槽で得られた沈殿物を分離するユニット８と、得られた沈殿物を濃縮脱水するユニット９と、スラッジを脱水するユニット１０とを備えたことを特徴とする溶融亜鉛メッキ工程で排出される亜鉛及び鉄を含む酸廃液から酸化亜鉛を回収する装置が提供される。
【０００５】
【発明の実施の形態】
本発明の溶融亜鉛メッキ工程で排出される亜鉛及び鉄を含む酸廃液処理法の１つの態様は、該被処理液を、ｐＨ９以上で５０℃以上の水酸化カルシウム懸濁液に滴下混合して、５０℃以上の温度及び６〜１１のｐＨを有する混合液を形成し、さらに、必要に応じて酸化剤を添加して、該溶存亜鉛イオンと鉄イオンを難溶性物質として沈殿させることを特徴とするものである。
【０００６】
前記混合液のｐＨは、一般的には、６〜１１の範囲、好ましくは８〜１１の範囲である。その混合液の温度は５０℃以上、好ましくは５０〜６０℃である。
【０００７】
本発明で用いる水酸化カルシウム懸濁液において、水酸化カルシウムの濃度は、０．０５〜１０％、好ましくは０．１〜８％である。被処理液と水酸化カルシウム懸濁液との混合温度は５０℃以上、通常５０〜６０℃であるが、この混合温度を得るには、被処理液と水酸化カルシウムとの混合物を加熱して５０℃以上にする方法や、被処理液又は水酸化カルシウム懸濁液あるいはその両方を５０℃以上に加熱しておき、両者を混合して５０℃以上の混合液を得る方法等がある。本発明の場合、その混合温度が５０℃未満であると、スラッジの量が多くなる等の問題が生じるので好ましくない。
【０００８】
本発明において、被処理液には酸化剤を添加するのが好ましい。酸化剤を使用しなくても溶存する亜鉛、鉄を沈殿物として回収できるが、酸化剤を使用することにより沈殿物の量を大幅に削減できる。使用する酸化剤は、廃水の処理に用いられているものであり、このようなものには、過酸化水素、塩素系酸化剤、オゾン等が包含される。酸化剤の使用量は、水中における濃度で、１〜２００ｍｇ／Ｌ、好ましくは１〜１００ｍｇ／Ｌである。
酸化剤の添加時期は、水酸化カルシウム懸濁液を添加した後でもよいし、水酸化カルシウム懸濁液と同時に添加してもよいし、水酸化カルシウム懸濁液を添加する前でもよい。
【０００９】
本発明においては、凝集剤を併用するのが好ましい。この場合の凝集剤は、フロックの凝集に用いられているものであり、このようなものには、ポリアクリルアミドのカチオン化変性物、ポリアクリル酸ジメチルアミノエチルエステル、ポリメタクリル酸ジメチルアミノエチルエステル、ポリエチレンイミン、キトサン等のカチオン性有機系凝集剤、ポリアクリルアミド等のノニオン性有機系凝集剤、ポリアクリル酸、アクリルアミドとアクリル酸との共重合体及びその塩等のアニオン性有機系凝集剤が包含される。凝集剤の使用量は、水中における濃度で、１〜２００ｍｇ／Ｌ、好ましくは１〜１００ｍｇ／Ｌである。
【００１０】
前記凝集工程終了後の沈殿物のフロックを含む被処理液は、固液分離処理される。この場合の固液分離方法としては、慣用の方法、例えば、濾過分離、遠心分離、沈降分離等が挙げられる。
この固液分離処理により液中の沈殿物は除去され、スラッジとなる。このスラッジは亜鉛を主体とするものである。
【００１１】
次に、本発明を図面を参照して説明する。
図１は本発明を実施する場合の装置系統図の１例を示すもので、溶融亜鉛メッキ工程で排出される亜鉛及び鉄を含む酸廃液を処理しそのスラッジを回収するものである。
図１において、１は原水槽、２は水酸化カルシウム懸濁液供給ユニット、３は温水供給ユニット、４は廃液と水酸化カルシウム懸濁液とを混合する反応槽、５は酸化剤添加ユニット、６は凝集剤添加ユニット、７は凝集槽、８は沈殿分離ユニット、９は沈殿物を濃縮脱水するユニット、１０はスラッジ脱水ユニットを示す。
また、１１は原水タンク、１２、１３はｐＨ計、１４は温水タンクを示す。
【００１２】
亜鉛及び鉄を含む酸廃液の供給法には、特に制限はないが、例えば、廃液排除管を配置し、廃液を原水槽１に導入しても良いし、廃液の貯蔵槽を別途設置し、そこから廃液を原水槽１に導入しても良い。
亜鉛及び鉄を含む酸廃液を、反応槽４で５０℃以上に加温された水酸化カルシウム懸濁液と混合させる。
【００１３】
加温した水酸化カルシウム懸濁液の供給方法としては、所定の濃度の水酸化カルシウム懸濁液を所定温度に加温してから供給してもよいし、温水と所定濃度よりも濃い水酸化カルシウム懸濁液とを別々に、所定濃度になるように反応槽に添加してもよい。この場合の水酸化カルシウム懸濁液の濃度は、所定の濃度よりも当然高くなければならないが、その割合は特に限定されず、反応槽４の温度を５０℃以上に維持できるものであればよい。
【００１４】
反応槽４の反応液に酸化剤供給ユニット５から酸化剤が添加される。この反応液は、さらに凝集槽７に移され凝集剤が添加された後、沈殿分離ユニット（固液分離槽）８に移され、固液分離される。沈殿物は沈殿分離ユニット８の底部から汚泥濃縮脱水ユニット９に移され、さらに濃縮脱水される。濃縮脱水された固形分はスラッジ脱水ユニット１０で脱水され、亜鉛資源として回収再利用される。
【００１５】
５０℃以上に保たれた水酸化カルシウム懸濁液の反応槽４に亜鉛及び鉄を含む酸廃液と水酸化カルシウム懸濁液を滴下しｐＨが６〜１１、好ましくは９から１１になるように混合する。水酸化カルシウム懸濁液を５０℃以上に保つためには、反応槽にヒーターを取り付けたものを用いても良いし、あらかじめ５０℃以上に加温した水酸化カルシウム懸濁液を滴下しても良い。
【００１６】
反応槽４に添加される水酸化カルシウム懸濁液の濃度は、０．０１〜１０％、好ましくは０．１〜５％である。
【００１７】
凝集槽７で用いられる凝集剤は、フロックの凝集に用いられているものであり、このようなものには、ポリアクリルアミドのカチオン化変性物、ポリアクリル酸ジメチルアミノエチルエステル、ポリメタクリル酸ジメチルアミノエチルエステル、ポリエチレンイミン、キトサン等のカチオン性有機系凝集剤、ポリアクリルアミド等のノニオン性有機系凝集剤、ポリアクリル酸、アクリルアミドとアクリル酸との共重合体及びその塩等のアニオン性有機系凝集剤が包含される。凝集剤の使用量は、水中における濃度で、１〜２００ｍｇ／Ｌ、好ましくは１〜１００ｍｇ／Ｌである。
【００１８】
本発明で採用している濃縮脱水ユニット９としては、従来一般の慣用の脱水装置、例えば遠心装置を使用しても良いが、本発明では自動化のため汚泥濃縮脱水槽を用いるのがよい。
【００１９】
本発明で採用しているスラッジ脱水ユニット１０としては、従来一般の慣用スラッジ脱水装置、例えばフィルタープレスを使用しても良いが、本発明では自動化のためスクリュープレスを用いるのがよい。
【００２０】
【実施例】
次に本発明を実施例によりさらに詳細に説明する。
【００２１】
実施例１
ｐＨが−１．８３、亜鉛濃度が２４２．５ｇ／Ｌ、鉄濃度が４８ｇ／Ｌ、塩素濃度が３８１ｇ／Ｌの溶融亜鉛メッキ工程で排出される亜鉛及び鉄を含む酸廃液を２５５ｍＬ／ｍｉｎ、５５℃に加温した水酸化カルシウム懸濁液（２％）６．４Ｌ／ｍｉｎを反応槽に送り撹拌混合し（ｐＨ約９．５〜１０となる）、過酸化水素水溶液（濃度３０％）２５．５ｍＬ／ｍｉｎを添加し（ｐＨ約９〜９．５となる）、滞留時間２０分で、凝集槽に送り、ここで高分子凝集剤ダイヤフロックＫＰ２０８ＢＨ ０．１％水溶液を３２０ｍＬ／ｍｉｎで添加し撹拌し、滞留時間２分で、沈殿槽へ送り、滞留時間２０分で、上澄水を処理水として排出した。沈殿したスラッジのＳＶ値は３５％であった。これを底部から排出し、汚泥濃縮脱水槽へ送って濃縮脱水し、滞留時間２０分でスラッジ脱水ユニットへ送り脱水した。処理水の亜鉛、鉄、塩素濃度は、それぞれ０．５６ｍｇ／Ｌ、０．１４ｍｇ／Ｌ及び５２００ｍｇ／Ｌであった。スラッジケーキ量は、廃液１Ｌ当たり、６３５ｇであった。スラッジを硝酸で溶解し、亜鉛、鉄及びカルシウムをＩＣＰ発光分析装置で、塩素イオンをイオンクロマトグラフで測定した結果、スラッジの組成（重量％）は、それぞれ、４７．９％、９．０％、７．５％、１．１％であった。
【００２２】
実施例２
実施例１において、酸化剤の過酸化水素水溶液を添加しない他は同様にして処理したところ、スラッジのＳＶ値は約４５％であった。スラッジの組成（重量％）は、亜鉛４１％、鉄８．２％、カルシウム１１％、塩素３．４％であった。
【００２３】
比較例１
実施例１において、温度を常温で行った以外は実施例１と同様に処理したところ、スラッジのＳＶ値は約９０％であった。スラッジの組成は、亜鉛３４％、鉄７．５％、カルシウム１４％、塩素１７％であった。
【００２４】
実施例３
実施例１の廃液を２５５ｍＬ／ｍｉｎと５５℃に加温した水３．２Ｌ／ｍｉｎと水酸化カルシウム懸濁液（４％）３．２Ｌ／ｍｉｎを反応槽に送り撹拌混合し、滞留時間１０分で、凝集槽に送り、ここで高分子凝集剤ダイヤフロックＫＰ２０８ＢＨ ０．１％溶液を３００ｍＬ／ｍｉｎで添加し撹拌し、滞留時間２分で沈殿槽へ送り、滞留時間２０分で、上澄水を処理水として排出した。沈殿したスラッジは底部から排出し、汚泥濃縮脱水槽へ送って濃縮脱水し、スラッジ脱水ユニニットで脱水した。得られた結果は、実施例１とほぼ同じであった。
【００２５】
【発明の効果】
本発明によれば、亜鉛及び鉄を含む酸廃液を効率よくかつ低められたスラッジ発生量で処理することができる。
【図面の簡単な説明】
【図１】本発明の方法を実施する場合の装置系統図の１例を示す。
【符号の説明】
１ 原水槽
２ 水酸化カルシウム懸濁液供給ユニット
３ 温水供給ユニット
４ 反応槽
５ 酸化剤供給ユニット
６ 凝集剤添加ユニット
７ 凝集槽
８ 沈殿槽
９ 濃縮脱水ユニット
１０ スラッジ脱水ユニット
１１ 原水タンク
１２、１３ ｐＨ計
１４ 温水タンク[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for treating molten zinc waste liquid.
[0002]
[Prior art]
Hot-dip galvanizing is widely used for various steel structures because it is inexpensive to apply and has corrosion resistance and durability superior to painting. Various acid waste liquids are discharged in the process of hot-dip galvanizing.Hydrochloric acid waste liquid and sulfuric acid containing zinc and iron, which are generated when dissolving the plating layer of defective products generated when hot-dip galvanizing steel products, in particular There is no effective treatment method for the waste liquid other than the neutralization method, which is a problem.
When the acid waste liquid is neutralized with an alkali, not only a large amount of alkali is consumed, but also a large amount of hydroxide sludge is formed as a result of the neutralization. Since the sludge is mixed with iron and zinc, it cannot be effectively used even if it is separated from water, so that there is a problem that a large amount of sludge must be discarded.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a method and an apparatus for efficiently and efficiently treating an acid waste liquid containing zinc and iron discharged in a hot-dip galvanizing process with a reduced amount of sludge.
[0004]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above problems, and as a result, completed the present invention.
That is, according to the present invention, in a method for treating an acid waste liquid containing zinc and iron discharged in a hot-dip galvanizing step as a liquid to be treated, the liquid to be treated is treated with a calcium hydroxide suspension having a pH of 9 or more and 50 ° C. or more. The mixture is added dropwise to the suspension to form a mixture having a temperature of 50 ° C. or more and a pH of 6 to 11, and if necessary, an oxidizing agent is added to make the dissolved zinc ions and iron ions hardly soluble. A method for recovering zinc oxide from an acid waste solution containing zinc and iron discharged in a hot dip galvanizing step, wherein the zinc oxide is precipitated as a substance and recovered is provided.
Furthermore, according to the present invention, there is provided an apparatus used in a method for treating an acid waste liquid containing zinc and iron discharged in the above-described hot-dip galvanizing step as a liquid to be treated, and the zinc discharged in the hot-dip galvanizing step. Raw water tank 1 for acid waste liquid containing iron and iron,
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
One embodiment of the method for treating an acid waste liquid containing zinc and iron discharged in the hot-dip galvanizing step of the present invention is to drop-mix the liquid to be treated with a calcium hydroxide suspension at
[0006]
The pH of the mixture is generally in the range of 6 to 11, preferably in the range of 8 to 11. The temperature of the mixture is 50 ° C. or higher, preferably 50 to 60 ° C.
[0007]
In the calcium hydroxide suspension used in the present invention, the concentration of calcium hydroxide is 0.05 to 10%, preferably 0.1 to 8%. The mixing temperature of the liquid to be treated and the suspension of calcium hydroxide is 50 ° C. or higher, usually 50 to 60 ° C. To obtain this mixing temperature, the mixture of the liquid to be treated and calcium hydroxide is heated. There is a method of heating to 50 ° C. or more, a method of heating the liquid to be treated and / or the calcium hydroxide suspension to 50 ° C. or more, and mixing them to obtain a mixed solution of 50 ° C. or more. In the case of the present invention, if the mixing temperature is lower than 50 ° C., problems such as an increase in the amount of sludge occur, which is not preferable.
[0008]
In the present invention, it is preferable to add an oxidizing agent to the liquid to be treated. Dissolved zinc and iron can be recovered as a precipitate without using an oxidizing agent, but the amount of the precipitate can be significantly reduced by using an oxidizing agent. The oxidizing agents used are those used in the treatment of wastewater, and include hydrogen peroxide, chlorine-based oxidizing agents, ozone, and the like. The amount of the oxidizing agent used is 1 to 200 mg / L, preferably 1 to 100 mg / L, as the concentration in water.
The oxidizing agent may be added after adding the calcium hydroxide suspension, simultaneously with the calcium hydroxide suspension, or before adding the calcium hydroxide suspension.
[0009]
In the present invention, a coagulant is preferably used in combination. The flocculant in this case is one used for flocculation of floc, such as a cationized modified product of polyacrylamide, poly (dimethylaminoethyl acrylate), poly (dimethylaminoethyl methacrylate), Includes cationic organic coagulants such as polyethyleneimine and chitosan; nonionic organic coagulants such as polyacrylamide; anionic organic coagulants such as polyacrylic acid, copolymers of acrylamide and acrylic acid, and salts thereof. Is done. The amount of the coagulant used is 1 to 200 mg / L, preferably 1 to 100 mg / L, in water.
[0010]
The liquid to be treated including the flocs of the precipitate after the aggregation step is subjected to a solid-liquid separation treatment. As the solid-liquid separation method in this case, a conventional method, for example, filtration separation, centrifugation, sedimentation and the like can be mentioned.
By this solid-liquid separation treatment, precipitates in the liquid are removed and sludge is formed. This sludge is mainly composed of zinc.
[0011]
Next, the present invention will be described with reference to the drawings.
FIG. 1 shows an example of an apparatus system diagram in the case of carrying out the present invention, in which an acid waste liquid containing zinc and iron discharged in a hot-dip galvanizing step is treated and sludge is collected.
In FIG. 1, 1 is a raw water tank, 2 is a calcium hydroxide suspension supply unit, 3 is a hot water supply unit, 4 is a reaction tank for mixing a waste liquid and a calcium hydroxide suspension, 5 is an oxidizing agent addition unit, Reference numeral 6 denotes a coagulant addition unit, 7 denotes a coagulation tank, 8 denotes a sedimentation separation unit, 9 denotes a unit for concentrating and dewatering the precipitate, and 10 denotes a sludge dewatering unit.
11 is a raw water tank, 12 and 13 are pH meters, and 14 is a hot water tank.
[0012]
The method for supplying the acid waste liquid containing zinc and iron is not particularly limited. For example, a waste liquid discharge pipe may be provided, the waste liquid may be introduced into the raw water tank 1, or a waste liquid storage tank may be separately provided. From there, the waste liquid may be introduced into the raw water tank 1.
The acid waste liquid containing zinc and iron is mixed with the calcium hydroxide suspension heated in the reaction tank 4 to 50 ° C. or higher.
[0013]
As a method for supplying the heated calcium hydroxide suspension, a calcium hydroxide suspension having a predetermined concentration may be supplied after being heated to a predetermined temperature, or hot water and a hydroxide having a concentration higher than the predetermined concentration may be supplied. The calcium suspension may be separately added to the reaction tank so as to have a predetermined concentration. In this case, the concentration of the calcium hydroxide suspension must be higher than a predetermined concentration, but the ratio is not particularly limited as long as the temperature of the reaction tank 4 can be maintained at 50 ° C. or higher. .
[0014]
An oxidant is added from the oxidant supply unit 5 to the reaction solution in the reaction tank 4. The reaction liquid is further transferred to a coagulation tank 7 and a coagulant is added thereto. Then, the reaction liquid is transferred to a precipitation / separation unit (solid-liquid separation tank) 8 to be subjected to solid-liquid separation. The sediment is transferred from the bottom of the sedimentation /
[0015]
The acid waste solution containing zinc and iron and the calcium hydroxide suspension are dropped into the reaction vessel 4 of the calcium hydroxide suspension maintained at 50 ° C. or higher so that the pH becomes 6 to 11, preferably 9 to 11. Mix. In order to maintain the calcium hydroxide suspension at 50 ° C. or higher, a reactor equipped with a heater may be used, or a calcium hydroxide suspension previously heated to 50 ° C. or higher may be dropped. good.
[0016]
The concentration of the calcium hydroxide suspension added to the reaction tank 4 is 0.01 to 10%, preferably 0.1 to 5%.
[0017]
The flocculant used in the flocculation tank 7 is used for floc flocculation. Examples of such flocculants include cationically modified polyacrylamide, dimethylaminoethyl polyacrylate, and dimethylamino methacrylate. Cationic organic flocculants such as ethyl ester, polyethyleneimine and chitosan; nonionic organic flocculants such as polyacrylamide; anionic organic flocculants such as polyacrylic acid, copolymers of acrylamide and acrylic acid and salts thereof Agents are included. The amount of the coagulant used is 1 to 200 mg / L, preferably 1 to 100 mg / L, in water.
[0018]
As the concentration and
[0019]
As the
[0020]
【Example】
Next, the present invention will be described in more detail with reference to examples.
[0021]
Example 1
The acid waste liquid containing zinc and iron discharged in the hot-dip galvanizing process having a pH of -1.83, a zinc concentration of 242.5 g / L, an iron concentration of 48 g / L, and a chlorine concentration of 381 g / L is 255 mL / min. 6.4 L / min of a calcium hydroxide suspension (2%) heated to 55 ° C. was sent to the reaction vessel and mixed by stirring (to have a pH of about 9.5 to 10), and an aqueous hydrogen peroxide solution (concentration: 30%) 25.5 mL / min is added (pH becomes about 9 to 9.5) and sent to a flocculation tank with a residence time of 20 minutes, where a 0.1% aqueous solution of polymer flocculant Diafloc KP208BH is added at 320 mL / min. The mixture was added, stirred, and sent to a sedimentation tank at a residence time of 2 minutes. At a residence time of 20 minutes, supernatant water was discharged as treated water. The SV value of the settled sludge was 35%. This was discharged from the bottom, sent to a sludge thickening and dewatering tank, concentrated and dewatered, and sent to a sludge dewatering unit with a residence time of 20 minutes to be dewatered. The concentrations of zinc, iron and chlorine in the treated water were 0.56 mg / L, 0.14 mg / L and 5200 mg / L, respectively. The amount of sludge cake was 635 g per liter of waste liquid. The sludge was dissolved in nitric acid, and zinc, iron and calcium were measured by an ICP emission spectrometer and chloride ions were measured by ion chromatography. As a result, the compositions (% by weight) of the sludge were 47.9% and 9.0%, respectively. , 7.5% and 1.1%.
[0022]
Example 2
When the same treatment as in Example 1 was carried out except that an aqueous solution of hydrogen peroxide as an oxidizing agent was not added, the SV value of the sludge was about 45%. The composition (% by weight) of the sludge was 41% zinc, 8.2% iron, 11% calcium, and 3.4% chlorine.
[0023]
Comparative Example 1
When the treatment was performed in the same manner as in Example 1 except that the temperature was changed to normal temperature, the SV value of the sludge was about 90%. The composition of the sludge was 34% zinc, 7.5% iron, 14% calcium and 17% chlorine.
[0024]
Example 3
The waste liquid of Example 1 was heated to 255 mL / min, 3.2 L / min of water heated to 55 ° C. and 3.2 L / min of a calcium hydroxide suspension (4%) were sent to the reaction tank and mixed by stirring. Minutes, the mixture is fed to a flocculation tank, where a 0.1% solution of polymer flocculant Diafloc KP208BH is added at 300 mL / min and stirred, sent to a sedimentation tank with a residence time of 2 minutes, and supernatant water is added for a residence time of 20 minutes. Was discharged as treated water. The precipitated sludge was discharged from the bottom, sent to a sludge thickening / dewatering tank, concentrated and dewatered, and dewatered with a sludge dewatering unit. The obtained results were almost the same as in Example 1.
[0025]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the acid waste liquid containing zinc and iron can be treated efficiently and with the reduced amount of sludge generated.
[Brief description of the drawings]
FIG. 1 shows an example of an apparatus system diagram for implementing a method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| JP2001055151A JP3598324B2 (en) | 2001-02-28 | 2001-02-28 | Method and apparatus for recovering zinc and iron in acid waste liquid as precipitate |
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| Application Number | Priority Date | Filing Date | Title |
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| JP2001055151A JP3598324B2 (en) | 2001-02-28 | 2001-02-28 | Method and apparatus for recovering zinc and iron in acid waste liquid as precipitate |
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| JP2002256353A JP2002256353A (en) | 2002-09-11 |
| JP3598324B2 true JP3598324B2 (en) | 2004-12-08 |
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| JP4632372B2 (en) * | 2007-03-23 | 2011-02-16 | 新日本製鐵株式会社 | Treatment method of waste water from hot-dip galvanized steel sheet manufacturing equipment |
| JP5904100B2 (en) * | 2012-11-20 | 2016-04-13 | 住友金属鉱山株式会社 | Method for settling and separating neutralized slurry and method for hydrometallizing nickel oxide ore |
| KR101622280B1 (en) | 2014-12-04 | 2016-05-18 | 주식회사 포스코 | Method for processing sludge |
| JP7497665B2 (en) | 2020-10-14 | 2024-06-11 | 住友金属鉱山株式会社 | Mixing vessel and replacement stand |
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