JP2021053580A - High-concentration iron-based flocculant, and method for producing same - Google Patents

High-concentration iron-based flocculant, and method for producing same Download PDF

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JP2021053580A
JP2021053580A JP2019179191A JP2019179191A JP2021053580A JP 2021053580 A JP2021053580 A JP 2021053580A JP 2019179191 A JP2019179191 A JP 2019179191A JP 2019179191 A JP2019179191 A JP 2019179191A JP 2021053580 A JP2021053580 A JP 2021053580A
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sulfate
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JP2021053580A5 (en
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洋介 桂
Yosuke Katsura
洋介 桂
正寛 伴
Masanori Ban
正寛 伴
達郎 戸嶋
Tatsuro TOSHIMA
達郎 戸嶋
正貴 中島
Masaki Nakajima
正貴 中島
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Nittetsu Mining Co Ltd
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Priority to CN202080068376.XA priority patent/CN114466824A/en
Priority to KR1020227014081A priority patent/KR20220069092A/en
Priority to PCT/JP2020/036337 priority patent/WO2021065732A1/en
Priority to TW109133870A priority patent/TW202122146A/en
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    • C01INORGANIC CHEMISTRY
    • C01GCOMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00Compounds of iron
    • C01G49/14Sulfates
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    • B01D21/00Separation of suspended solid particles from liquids by sedimentation
    • B01D21/01Separation of suspended solid particles from liquids by sedimentation using flocculating agents
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    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/52Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents

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Abstract

To enable an ultra-high concentration polyferric sulfate solution, which could not be produced through conventional production methods due to a long reaction time, to be produced in a short time.SOLUTION: When a sulfate ion concentration is [SO42-] and the total iron concentration is [T-Fe] (in molar concentration), raw materials are adjusted such that the following relationships are satisfied, and said polyferric sulfate solution is produced through a high-temperature and high-pressure reaction of the raw materials. The molar ratio (SO42-/T-Fe) of sulfate ions to total iron is at least 1.2, and when the weight concentration of sulfate ions is [SO42-], [SO42-] is at most 35 wt.%.SELECTED DRAWING: Figure 1

Description

本発明は、排水処理に使用される高濃度の鉄系凝集剤及びその製造方法に関する。 The present invention relates to a high-concentration iron-based flocculant used for wastewater treatment and a method for producing the same.

本件特許出願人は、独自に開発した鉄系無機高分子凝集剤「ポリテツ」(登録商標)を中心に排水処理薬剤の販売を行っており、これに関するいくつかの特許を有する。
これらの特許のうち、特許文献1には、鉄系原料である硫酸第一鉄(FeSO)溶液に対して触媒として亜硝酸ナトリウム及び酸化剤を添加して、常温常圧で約10時間程度の時間をかけて酸化反応を進行させ、ポリ硫酸第二鉄(〔Fe(OH)(SO3−n/2〕m但し0<n≦2、mは自然数)溶液を得る方法が記載されている。
しかし、この方法は反応に長時間を要するので、何らかの方法により反応時間の短縮化が求められていた。
The patent applicant sells wastewater treatment chemicals centering on the iron-based inorganic polymer flocculant "Polytetsu" (registered trademark), which was originally developed, and holds several patents related to this.
Of these patents, Patent Document 1 includes adding sodium nitrite and an oxidizing agent as catalysts to a ferrous sulfate (FeSO 4 ) solution, which is an iron-based raw material, at room temperature and pressure for about 10 hours. A method of obtaining a solution of ferric polysulfate ([Fe 2 (OH) n (SO 4 ) 3-n / 2 ] m, where 0 <n ≦ 2, m is a natural number) by advancing the oxidation reaction over a period of time. Is described.
However, since this method requires a long time for the reaction, it has been required to shorten the reaction time by some method.

また、特許文献2に記載された鉄系無機凝集剤の製造方法は、鉄系原料としてマグネタイト(Fe)を使用し、硫酸イオンと鉄イオンのモル比を調整した後に、密閉容器中で120〜180℃の温度で反応させる方法である。この方法は高温高圧下で反応を進めることにより反応時間の短縮化を目指す製造方法であるが、それでも0.8〜1.5時間の反応時間が必要であった。 Further, in the method for producing an iron-based inorganic flocculant described in Patent Document 2, magnetite (Fe 3 O 4 ) is used as an iron-based raw material, the molar ratio of sulfate ion to iron ion is adjusted, and then in a closed container. It is a method of reacting at a temperature of 120 to 180 ° C. This method is a production method aiming at shortening the reaction time by advancing the reaction under high temperature and high pressure, but still requires a reaction time of 0.8 to 1.5 hours.

特許文献3には、鉄系原料である三酸化二鉄(Fe23)を過剰の硫酸に溶解して硫酸第二鉄(Fe2(SO4)を生成し、これを含水三酸化二鉄で部分中和する鉄系凝集剤の製造方法が開示されている。
しかし、この方法は、三酸化二鉄を硫酸に溶解させる工程と生成した硫酸第二鉄を部分中和する工程の2工程からなるので、製造工程が複雑になり効率よくポリ硫酸第二鉄溶液を生成することができないという難点がある。実施例では100℃に加熱した状態で3時間程度保持し、反応を進行させることが必要とされている。
In Patent Document 3, ferric trioxide (Fe 2 O 3 ), which is an iron-based raw material, is dissolved in excess sulfuric acid to produce ferric sulfate (Fe 2 (SO 4 ) 3 ), which is hydrous. A method for producing an iron-based flocculant that is partially neutralized with ferric oxide is disclosed.
However, since this method consists of two steps, a step of dissolving ferric trioxide in sulfuric acid and a step of partially neutralizing the produced ferric sulfate, the manufacturing process becomes complicated and the polyferric sulfate solution is efficiently prepared. Has the drawback of not being able to generate. In the examples, it is required to keep the mixture heated to 100 ° C. for about 3 hours to allow the reaction to proceed.

特公昭51−17516号公報Special Publication No. 51-17516 特許第3379204号公報Japanese Patent No. 3379204 特許第2741137号公報Japanese Patent No. 2741137

上記したように、従来技術においては、様々な種類の鉄化合物を鉄系原料として選択し、様々な反応形態で反応させてポリ硫酸第二鉄溶液を製造することが試みられているが、遊離硫酸や反応残渣の発生が多い等の問題のほか、実用に耐えるポリ硫酸第二鉄溶液を製造するための製造時間が長くなるという問題が残されていた。
また、詳細は後記するが、鉄系凝集剤においては、全鉄濃度が高いほど凝集剤としての特性が高いとされている。そして、本件特許出願人は、鉄系無機高分子凝集剤「ポリテツ」(商標登録)を製造・販売しており、その全鉄濃度は、概ね11.0〜12.5%(「通常品」と称する)である。鉄系無機高分子凝集剤は、その全鉄濃度が高濃度であれば、高い凝集能力と脱水性を有することから、近年では、全鉄濃度が12.5以上のものを「高濃度品」として製造・販売されてきている。
しかしながら、全鉄濃度の高い凝集剤を製造することとしても、上記の製造時間が長くなるとの問題とも関係して、せいぜい全鉄濃度が12.7%程度(13%未満)が限度であり、13.0%以上のポリ硫酸第二鉄溶液を市販品として製造することはできなかった。
As described above, in the prior art, attempts have been made to select various types of iron compounds as iron-based raw materials and react them in various reaction forms to produce a ferric polysulfate solution, but they are free. In addition to the problem that a large amount of sulfuric acid and reaction residue are generated, there remains a problem that the production time for producing a ferric polysulfate solution that can withstand practical use becomes long.
Further, as will be described in detail later, it is said that the higher the total iron concentration of the iron-based coagulant, the higher the characteristics as the coagulant. The patent applicant manufactures and sells the iron-based inorganic polymer flocculant "Polytetsu" (registered trademark), and its total iron concentration is approximately 11.0 to 12.5% ("normal product"). (Called). Iron-based inorganic polymer flocculants have high coagulation ability and dehydration property if the total iron concentration is high. Therefore, in recent years, iron-based inorganic polymer flocculants having a total iron concentration of 12.5 or more are "high-concentration products". Has been manufactured and sold as.
However, even when a flocculant having a high total iron concentration is produced, the total iron concentration is limited to about 12.7% (less than 13%) at most in relation to the above-mentioned problem that the production time becomes long. It was not possible to produce a ferric polysulfate solution of 13.0% or more as a commercial product.

なお、本発明における濃度は、モル濃度であることを明記する場合以外は全て重量%を意味するものであり、[T−Fe]は全鉄の重量濃度、[SO4 2-]は硫酸イオンの重量濃度を表すものとする。
ここで全鉄濃度とは、原料中に溶解している鉄ばかりでなく、溶解することなく固体(粉体等)として原料液中に存在する鉄を含めた濃度であることを意味する。原料液中に存在する鉄系粉末であっても、ポリ硫酸第二鉄溶液の製造反応に寄与するので、原料液中に溶解していない鉄系成分も鉄の濃度に含めることが合理的である。
しかし、本発明で製造したポリ硫酸第二鉄溶液でも、全鉄濃度で濃度表示をするが、鉄はすべて溶解していることは当然のことである。
The concentration in the present invention is intended to mean all the weight% except where noted that the molar concentration, [T-Fe] has a weight percentage of total iron, [SO 4 2-] sulfate ion It shall represent the weight concentration of.
Here, the total iron concentration means a concentration including not only iron dissolved in the raw material but also iron existing in the raw material liquid as a solid (powder or the like) without being dissolved. Even iron-based powder present in the raw material solution contributes to the production reaction of the ferric polysulfate solution, so it is rational to include iron-based components that are not dissolved in the raw material solution in the iron concentration. is there.
However, even in the ferric polysulfate solution produced in the present invention, the concentration is indicated by the total iron concentration, but it is natural that all the iron is dissolved.

本発明は、これらの課題を解決すべくなされたもので、従来品と比較して、全鉄濃度が高いポリ硫酸第二鉄溶液を短時間で製造することができる製造方法を提供することにある。 The present invention has been made to solve these problems, and an object of the present invention is to provide a production method capable of producing a ferric polysulfate solution having a high total iron concentration in a short time as compared with a conventional product. is there.

これらの課題を解決するため、本発明は、次の技術的手段から構成されるものである。
(1)次の条件を満たす硫酸第一鉄と硫酸を含む原料液を密閉容器中において高温高圧条件下で反応させることからなるポリ硫酸第二鉄溶液を含有する鉄系凝集剤の製造方法。
全鉄と硫酸イオンのモル比(SO 2-/T−Fe)が1.2以上
硫酸イオンの重量濃度を[SO 2-] としたときに、[SO 2-]が35重量%以下
(2)触媒として、硝酸又は亜硝酸塩を密閉容器中にさらに加えることを特徴とする(1)の鉄系凝集剤の製造方法。
(3)高温高圧の反応条件が、温度100℃以上、圧力0.3MPa以上であることを特徴とする(1)又は(2)の鉄系凝集剤の製造方法。
(4)全鉄濃度が13〜16重量%の高濃度ポリ硫酸第二鉄溶液である鉄系凝集剤。
In order to solve these problems, the present invention comprises the following technical means.
(1) A method for producing an iron-based flocculant containing a polyferric sulfate solution, which comprises reacting a ferric sulfate and a raw material liquid containing sulfuric acid satisfying the following conditions in a closed container under high temperature and high pressure conditions.
When the molar ratio of total iron and sulfate ion (SO 4 2- / T-Fe ) is a weight concentration of 1.2 or more sulfate ions [SO 4 2-], [SO 4 2-] is 35 wt% The method for producing an iron-based flocculant according to the following (2), which comprises further adding nitric acid or nitrite as a catalyst into a closed container.
(3) The method for producing an iron-based flocculant according to (1) or (2), wherein the reaction conditions of high temperature and high pressure are a temperature of 100 ° C. or higher and a pressure of 0.3 MPa or higher.
(4) An iron-based flocculant which is a high-concentration ferric sulfate solution having a total iron concentration of 13 to 16% by weight.

本発明の超高濃度鉄系凝集剤は、本発明の出願人が市販している高濃度の鉄系凝集剤に比較しても高濃度である点に特徴があり、高い凝集能力と脱水性を有している。また、通常品に比較して含有水分が少ないことから、製品輸送コストを低減することができる。
また、本発明の鉄系凝集剤の製造方法によれば、従来の方法では10時間以上の時間を要していた製造時間を大幅に短縮することができ、鉄系凝集剤の効率的な製造を行なうことができる。
The ultra-high-concentration iron-based flocculant of the present invention is characterized in that it has a higher concentration than the high-concentration iron-based flocculant commercially available by the applicant of the present invention, and has high flocculation ability and dehydration. have. In addition, since the water content is less than that of a normal product, the product transportation cost can be reduced.
Further, according to the method for producing an iron-based flocculant of the present invention, the production time, which required 10 hours or more in the conventional method, can be significantly shortened, and the iron-based flocculant can be efficiently produced. Can be done.

高温高圧反応でポリ硫酸第二鉄の製造が可能な領域Area where ferric polysulfate can be produced by high-temperature and high-pressure reaction 殿物が発生したサンプルのろ過後の濃度シフトConcentration shift after filtration of samples with burrows 殿物が発生しなかったサンプルの濃縮後の濃度シフトConcentration shift after concentration of samples with no blemishes

ここで、本発明に係る鉄系凝集剤の製造方法の技術的特徴について説明する前に、まず、無機系凝集剤について説明する。
一般に、下水汚泥処理においては、汚泥中の懸濁粒子やコロイド状粒子を凝集剤で凝集させて脱水処理して固液分離することが行われている。下水汚泥中の懸濁粒子やコロイド状粒子は、その表面が通常は負に帯電しており、表面電荷による反発力と水和により安定状態にある。凝集剤はこれらの粒子表面に吸着して表面電荷を中和し、粒子間の反発力を弱めることにより凝集させる作用を持つ薬剤である。
Here, before explaining the technical features of the method for producing an iron-based flocculant according to the present invention, first, an inorganic flocculant will be described.
Generally, in sewage sludge treatment, suspended particles and colloidal particles in sludge are agglomerated with a flocculant and dehydrated for solid-liquid separation. The surface of suspended particles and colloidal particles in sewage sludge is usually negatively charged, and is in a stable state due to repulsive force and hydration due to the surface charge. The aggregating agent is a drug having an action of adsorbing on the surface of these particles to neutralize the surface charge and weakening the repulsive force between the particles to cause agglomeration.

鉄系凝集剤は代表的な無機系凝集剤で、正に帯電した鉄イオンが懸濁粒子やコロイド状粒子等の懸濁物質の表面の負の電荷を中和して凝集作用を行っている。このため、鉄系凝集剤は鉄イオンが存在すれば必ず凝集作用を有するが、鉄イオン濃度が高ければ懸濁物質の凝集能力が高まるため、凝集剤の添加量は少なくてすむことになる。
また、凝集剤中の鉄イオンが安定的に存在するためには、ある程度の量の負イオンが存在しなければならない。鉄系凝集剤の場合には、通常は硫酸イオンがこの役割を担っている。負イオンが鉄イオン量と適切なモル比の関係にあれば鉄系凝集剤は安定するが、負イオン量が過剰な場合や不足する場合には不安定になり、結晶等として析出してしまう。
The iron-based flocculant is a typical inorganic flocculant, and positively charged iron ions neutralize the negative charge on the surface of suspended substances such as suspended particles and colloidal particles to perform a flocculant action. .. Therefore, the iron-based flocculant always has an agglutinating action in the presence of iron ions, but if the iron ion concentration is high, the agglutinating ability of the suspended substance is increased, so that the amount of the flocculant added can be small.
Further, in order for the iron ions in the flocculant to be stably present, a certain amount of negative ions must be present. In the case of iron-based flocculants, sulfate ions usually play this role. If the amount of negative ions has an appropriate molar ratio with the amount of iron ions, the iron-based flocculant will be stable, but if the amount of negative ions is excessive or insufficient, it will become unstable and precipitate as crystals. ..

また、このような鉄系凝集剤を用いて下水汚泥の処理を行った場合、鉄イオンは懸濁粒子やコロイド状粒子表面に吸着されて固形分として分離回収されるが、硫酸イオンは被処理水中に残留してしまう。
このため、被処理水は強度の酸性となるので、これを河川に放流するためには多量の中和剤で中和する必要があり、これが下水汚泥処理のコストを上げる要因の一つであるといわれている。すなわち、鉄系凝集剤に求められる特徴として、凝集剤中に含まれる全鉄濃度([T−Fe])が高く、硫酸イオン濃度([SO 2-])が低いことが求められていた。
When sewage sludge is treated with such an iron-based flocculant, iron ions are adsorbed on the surface of suspended particles or colloidal particles and separated and recovered as solids, but sulfate ions are treated. It remains in the water.
For this reason, the water to be treated becomes strongly acidic, and it is necessary to neutralize it with a large amount of neutralizing agent in order to discharge it into the river, which is one of the factors that increase the cost of sewage sludge treatment. It is said that. That is, as a feature required for iron-based flocculants, total iron concentration in the coagulant ([T-Fe]) is high sulfate ion concentration ([SO 4 2-]) that has been required low ..

硫酸第一鉄を原料とするポリ硫酸第二鉄溶液の製造においては、次の化学反応が進行していると考えられている。

m[2FeSO+(1-n/2)HSO+1/2O+(n-1)HO]
→ 〔Fe(OH)(SO3−n/2
但し0<n≦2、mは自然数

本発明は、上記したポリ硫酸第二鉄溶液からなる鉄系凝集剤について、[T−Fe]が高い溶液を短時間で形成する方法及びこれにより製造された鉄系凝集剤を提供するものである。
In the production of a polyferric sulfate solution using ferrous sulfate as a raw material, it is considered that the following chemical reaction is proceeding.

m [2FeSO 4 + (1-n / 2) H 2 SO 4 + 1 / 2O 2 + (n-1) H 2 O]
→ [Fe 2 (OH) n (SO 4 ) 3-n / 2 ] m
However, 0 <n ≦ 2, m is a natural number

The present invention provides a method for forming a solution having a high [T-Fe] in a short time with respect to the iron-based flocculant composed of the above-mentioned ferric sulfate solution, and an iron-based flocculant produced thereby. is there.

本発明においては、固体原料として硫酸第一鉄(FeSO4)を用い、高温高圧条件下で酸化反応を行なうにあたり、投入する原料液の全鉄濃度と硫酸イオン濃度との関係を特定の範囲のものに設定するものである。本発明は、全鉄と硫酸イオンのモル比(SO 2-/T−Fe)が特定値以上で、硫酸イオン濃度[SO 2-] が特定値以下のものとすることにより、従来技術からは予測のできない短時間で反応を終了することができ、さらに、製造されたポリ硫酸第二鉄溶液は従来技術では製造できない超高濃度の全鉄濃度([T−Fe])のものを製造できる、という格別に顕著な効果を達成するものである。 In the present invention, when ferrous sulfate (FeSO 4 ) is used as a solid raw material and the oxidation reaction is carried out under high temperature and high pressure conditions, the relationship between the total iron concentration and the sulfate ion concentration of the raw material liquid to be added is within a specific range. It is to be set to the thing. The invention, in all the molar ratio of iron and sulfate ion (SO 4 2- / T-Fe ) is a specific value or more, by the sulfate ion concentration [SO 4 2-] is to the following specific values, the prior art The reaction can be completed in a short time that cannot be predicted from the above, and the produced ferric sulfate solution has an ultra-high total iron concentration ([T-Fe]) that cannot be produced by conventional techniques. It achieves the exceptionally remarkable effect of being able to be manufactured.

すなわち、本発明においては、次の条件を満たす硫酸第一鉄と硫酸を含む原料液を高温高圧条件下で反応させることを特徴とする。
全鉄と硫酸イオンのモル比(SO 2-/T−Fe)が1.2以上
硫酸イオンの重量濃度を[SO 2-] としたときに、[SO 2-]が35重量%以下
硫酸第一鉄の全鉄濃度と硫酸イオン濃度とがこのような関係にあるとき、殿物を発生させることなく、短時間で超高濃度のポリ硫酸第二鉄溶液を得ることができることは、本発明者らにより見出された新たな知見である。
That is, the present invention is characterized in that a raw material liquid containing ferrous sulfate and sulfuric acid satisfying the following conditions are reacted under high temperature and high pressure conditions.
When the molar ratio of total iron and sulfate ion (SO 4 2- / T-Fe ) is a weight concentration of 1.2 or more sulfate ions [SO 4 2-], [SO 4 2-] is 35 wt% Hereinafter, when the total iron concentration of ferrous sulfate and the ion concentration of sulfate have such a relationship, it is possible to obtain an ultra-high concentration ferrous sulfate solution in a short time without generating ridges. , A new finding found by the present inventors.

(高温高圧反応)
特許文献1に記載された方法は、本発明者らが実施している従来の製造方法である。この方法では、反応は常温常圧下で固相、液相、気相の三相が相互に関係しあって反応が進行するものと考えられる。なぜなら、反応を進行している間、NO由来の黄褐色気体の発生やNO臭が感得されたからである。
しかし、本発明の方法では、反応終了後にオートクレーブを開放してもNO臭が感得されなかった。このため、本発明の高温高圧反応では、固体原料であるFeSO4・7H2Oが硫酸液中に溶解して酸化反応が進行するという固相と液相の関係した反応が進行していると推測される。
そうすると、高温条件下の反応であることにより固体原料であるFeSO4・7H2Oの溶解が進行しやすくなるし、高圧条件下の反応であることにより酸素分圧が上昇して液相中の溶存酸素量が増大し、これにより溶存酸素が亜硫酸イオンNO2−やFe2+の酸化に直接寄与し、鉄イオンの酸化反応が飛躍的に促進すると考えられる。
(High temperature and high pressure reaction)
The method described in Patent Document 1 is a conventional manufacturing method carried out by the present inventors. In this method, it is considered that the reaction proceeds under normal temperature and pressure in which the three phases of the solid phase, the liquid phase, and the gas phase are interrelated with each other. This is because, while the reaction proceeds, because generation and NO x odor tan gases from NO x is kantoku.
However, in the method of the present invention, NO x odor the autoclave was opened was not kantoku after the reaction. Therefore, in the high-temperature high-pressure reaction of the present invention, when a solid material FeSO 4 · 7H 2 O are related solid and liquid phases that progresses dissolved to oxidation in sulfuric acid solution reaction proceeds Guess.
Then, by the reaction of high-temperature conditions to dissolution of FeSO 4 · 7H 2 O is a solid material tends to progress, in the liquid phase with an oxygen partial pressure increases by the reaction of the high-pressure conditions It is considered that the amount of dissolved oxygen increases, which directly contributes to the oxidation of sulfite ions NO 2 − and Fe 2+ , and dramatically promotes the oxidation reaction of iron ions.

(反応温度と圧力)
容器内の温度は100〜150℃の範囲に調整することが必要である。
反応温度が100℃に満たないと硫酸第一鉄の酸化反応が十分に進行しない。また、150℃を超えると黄色の殿物が残存することが確認されており、この殿物はX線分析によりFe(OH)SO4であることが判明している。
具体的な実験データは省略するが、本発明者らは反応圧力が高いほど反応は効果的に進行することを確認している。このことは、上記した高温高圧反応の反応機構を考慮すれば当然のことといえる。
したがって、本発明の反応圧力は、製造コスト等を考慮して現実的な条件を設定すればよく、反応圧力0.3MPa以上であればよい。
(Reaction temperature and pressure)
The temperature inside the container needs to be adjusted in the range of 100 to 150 ° C.
If the reaction temperature is less than 100 ° C., the oxidation reaction of ferrous sulfate does not proceed sufficiently. In addition, it has been confirmed that yellow ridges remain when the temperature exceeds 150 ° C, and these ridges have been found to be Fe (OH) SO 4 by X-ray analysis.
Although specific experimental data are omitted, the present inventors have confirmed that the reaction proceeds more effectively as the reaction pressure increases. This can be said to be natural when the reaction mechanism of the high-temperature and high-pressure reaction described above is taken into consideration.
Therefore, the reaction pressure of the present invention may be set to realistic conditions in consideration of the manufacturing cost and the like, and the reaction pressure may be 0.3 MPa or more.

(触媒)
前記したポリ硫酸第二鉄溶液の生成反応を促進するために、触媒を使用することが好ましい。反応を促進するために好ましい触媒としては、硝酸、亜硝酸塩が挙げられ、亜硝酸塩としては亜硝酸のナトリウム塩、カリウム塩等がある。反応を促進する機能やコストの面からは、硝酸が好ましい。
[実験1]
(catalyst)
It is preferable to use a catalyst in order to accelerate the reaction for producing the above-mentioned ferric sulfate solution. Preferred catalysts for accelerating the reaction include nitric acid and nitrite, and examples of nitrite include sodium salt and potassium salt of nitrite. Nitric acid is preferable from the viewpoint of the function of promoting the reaction and the cost.
[Experiment 1]

本発明の発明者らは、高温高圧の反応条件として、反応温度を110℃、反応圧力を0.30MPa、反応時間を10分と設定して、硫酸第一鉄及び硫酸を含む原料液を種々の濃度となるように調整した。これに触媒として硝酸を添加して高温高圧反応をおこなった。そして、反応時間経過後に殿物が発生するか否かを検討した。
[実験2]
The inventors of the present invention set the reaction temperature to 110 ° C., the reaction pressure to 0.30 MPa, and the reaction time to 10 minutes as the reaction conditions of high temperature and high pressure, and various raw material solutions containing ferrous sulfate and sulfuric acid were used. The concentration was adjusted to be. Nitric acid was added to this as a catalyst to carry out a high-temperature and high-pressure reaction. Then, it was examined whether or not the palace was generated after the reaction time had elapsed.
[Experiment 2]

また、高温高圧の反応条件として、反応温度を120℃、反応圧力を10.00MPa、反応時間を10分と設定して、硫酸第一鉄及び硫酸を含む原料液を種々の濃度となるように調整した。これに触媒として硝酸を添加して高温高圧反応をおこなった。そして、反応時間経過後に殿物が発生するか否かを検討した。 Further, as the reaction conditions of high temperature and high pressure, the reaction temperature is set to 120 ° C., the reaction pressure is set to 10.00 MPa, and the reaction time is set to 10 minutes so that the raw material liquid containing ferrous sulfate and sulfuric acid has various concentrations. It was adjusted. Nitric acid was added to this as a catalyst to carry out a high-temperature and high-pressure reaction. Then, it was examined whether or not the palace was generated after the reaction time had elapsed.

殿物が発生するか否かの実験結果を、表1及び表2にまとめた。
実験1の反応温度110℃、反応圧力0.30MPaの条件で行った場合と、実験2の120℃、10.00MPaで行った場合とで、殿物の発生に関して全く同じ結果であることが判明した。すなわち、表1と表2の結果は、実験1と実験2に共通するものである。
表1で示す全鉄濃度[T−Fe]と全硫酸濃度[SO4 2-]の場合には、殿物が形成されずにポリ硫酸第二鉄溶液が形成されたもので、本発明の実施例である。また、表2で示す場合には殿物の発生が確認されたもので、本発明の比較例である。
Tables 1 and 2 summarize the experimental results of whether or not a burial is generated.
It was found that the results of the reaction temperature of Experiment 1 at 110 ° C. and the reaction pressure of 0.30 MPa were exactly the same as those of Experiment 2 at 120 ° C. and 10.00 MPa. did. That is, the results in Tables 1 and 2 are common to Experiment 1 and Experiment 2.
Total iron concentration shown in Table 1 [T-Fe] and in the case of total sulfuric acid concentration [SO 4 2-] is intended to ferric polysulfate solution was formed without Tono was formed, the present invention It is an embodiment. Further, in the case shown in Table 2, the occurrence of burrs was confirmed, which is a comparative example of the present invention.

Figure 2021053580

Figure 2021053580
(特定領域)
これらの結果をまとめたものを図1に示す。図中○印で占められた領域は、殿物が形成されずにポリ硫酸第二鉄溶液が形成された領域である。これは、本発明で規定する領域で、以下では「特定領域」という。この特定領域に含まれる白○印が示す[T−Fe]、[SO4 2-] が本発明の実施例の原料組成である。この組成物を高温高圧条件下で反応させることにより、ポリ硫酸第二鉄の赤褐色の溶液を得ることができた。
一方、特定領域の外側にある▲印が示す原料組成を用いて、高温高圧下で反応を行なわせたものが本発明の比較例にあたる。これらの組成物を用いた場合には、いずれも殿物の発生が確認されており、全鉄と硫酸イオンのモル比(SO4 2-/T−Fe)が1.2より低い領域のサンプルでは、殿物はハイドロニウムジャロサイトであることが確認されている。
Figure 2021053580

Figure 2021053580
(Specific area)
A summary of these results is shown in FIG. The area occupied by the circle in the figure is the area where the ferric polysulfate solution was formed without forming the ridge. This is an area defined by the present invention, and will be referred to as a "specific area" below. Shows white ○ mark included in the specific area [T-Fe], [SO 4 2-] is the raw material composition of an embodiment of the present invention. By reacting this composition under high temperature and high pressure conditions, a reddish brown solution of ferric polysulfate could be obtained.
On the other hand, a comparative example of the present invention is one in which the reaction is carried out under high temperature and high pressure using the raw material composition indicated by the ▲ mark on the outside of the specific region. In the case of using these compositions, both are confirmed generation of gluteal thereof, the total molar ratio of iron and sulfate ion (SO 4 2- / T-Fe ) is less than 1.2 area samples It has been confirmed that the palace is hydronium jarosite.

本発明者らは、この特定領域を次の2つの式から特定することとした。
まず、この領域の上限は、硫酸イオンの重量濃度[SO4 2-]が35重量%以下と設定することができる。
次に、この領域の下限は、右肩上がりの斜めの直線で規定できる。この斜めの直線は、全鉄と硫酸イオンのモル比(SO4 2-/T−Fe)が1.2以上となる関係を示す直線を、縦軸と横軸が硫酸イオンの重量濃度と全鉄の重量濃度である図に換算して書き込んだものである。
本発明で特定する上記の[T−Fe]と[SO4 2-]の原料組成に関する特定領域は、高温高圧条件下でポリ硫酸第二鉄溶液の生成を安定的に行うことができる領域を示している。
The present inventors have decided to specify this specific region from the following two equations.
First, the upper limit of this region can be a weight concentration of sulfate [SO 4 2-] is set to 35 wt% or less.
Next, the lower limit of this region can be defined by a diagonal straight line rising to the right. The oblique straight line, the straight line indicating the relationship between the molar ratio of total iron and sulfate ion (SO 4 2- / T-Fe ) is 1.2 or more, the vertical and horizontal axes and the weight concentration of sulfate ion all It is written by converting it into a figure showing the weight concentration of iron.
Above that specified in the present invention [T-Fe] and a specific area regarding feed composition of [SO 4 2-] is a region which can be generated in the ferric polysulfate solution stably at high temperature and pressure conditions Shown.

この特定領域の技術的意味は、次の追加実験1及び2からも確認することができる。
(追加実験1)
図1中で[T−Fe]と[SO4 2-] の濃度が、それぞれ、14%と28%のサンプル(以下、(14.0:28.0)と標記する) 及び、(15.0:30.0)のサンプルは殿物が発生している。このサンプルについて濾過を行い殿物を除去した後の溶液の濃度を測定したところ、その溶液の組成は、それぞれ(12.8:27.2)、(14.5:29.8)となる。
これは、本発明で規定する領域内の数値である。すなわち、殿物が発生したサンプルであっても、その溶液の部分は本発明で規定する全鉄濃度と全硫酸イオン濃度の特定領域内に含まれる組成であることが解った。図2にその内容を示す。
The technical meaning of this specific area can also be confirmed from the following additional experiments 1 and 2.
(Additional experiment 1)
The concentration of the in Figure 1 [T-Fe] and [SO 4 2-], respectively, 14% and 28% of the sample (hereinafter, (14.0: 28.0) to give the title) and: Sample (15.0 30.0) There is a palace. When the concentration of the solution was measured after filtering this sample and removing the deposits, the composition of the solution was (12.8: 27.2) and (14.5: 29.8), respectively.
This is a numerical value within the region specified in the present invention. That is, it was found that even in the sample in which the lumps were generated, the portion of the solution was contained within the specific regions of the total iron concentration and the total sulfate ion concentration specified in the present invention. The contents are shown in FIG.

(追加実験2)
(15.0:32.0)(15.0:34.0)のサンプルは、図1によれば、いずれも殿物の発生していないサンプルである。これらのサンプルを、(i)乾燥機内で50℃、(ii)実験室内で約20℃、(iii)インキュベータ内で10℃の3つの環境下に保持して1ヵ月後の変化を観察した。その結果、(i)乾燥機内で50℃に保持した(15.0:34.0)のサンプルのみに殿物が観察されるに至った。
(Additional experiment 2)
According to FIG. 1, the samples of (15.0: 32.0) and (15.0: 34.0) are all samples in which no ridges are generated. These samples were kept in three environments of (i) 50 ° C. in a dryer, (ii) about 20 ° C. in a laboratory, and (iii) 10 ° C. in an incubator, and changes were observed after one month. As a result, (i) the ridges were observed only in the sample kept at 50 ° C in the dryer (15.0: 34.0).

この原因は次の点にあると考えられる。
乾燥機内で50℃に一ヶ月間保持されたサンプル(15.0:32.0)(15.0:34.0)について、[T−Fe]と[SO4 2-] を再度測定したところ、それぞれの測定値は、(16.0:34.0)(16.0:36.0)であった。図3にその内容を示す。
乾燥機内で保持されたサンプルは水分が蒸発して濃縮されたが、濃縮があっても本発明で規定する領域内の[T−Fe]と[SO4 2-] の濃度関係を有するサンプルでは殿物は検出されない。しかし、濃縮により両者の濃度関係が上記領域から逸脱してしまったサンプルでは、濃縮の結果殿物が発生のである。
このため、(i)の条件下の(15.0:34.0)のサンプルのみに殿物が発生するのである。
The cause of this is considered to be as follows.
When [T-Fe] and [SO 4 2- ] were measured again for the samples (15.0: 32.0) (15.0: 34.0) kept at 50 ° C for one month in the dryer, the measured values were (15.0: 32.0). It was 16.0: 34.0) (16.0: 36.0). The contents are shown in FIG.
Sample held in a dryer is moisture has been concentrated by evaporation, the sample having a concentration relationship [T-Fe] and [SO 4 2-] in the area defined by even present invention there is enriched No palace is detected. However, in the sample in which the concentration relationship between the two deviates from the above region due to the concentration, a lump is generated as a result of the concentration.
For this reason, ridges occur only in the sample under the condition (i) (15.0: 34.0).

(反応時間)
特許文献1に記載された従来技術による製造方法は、硫酸第一鉄を常温常圧で酸化する方法で、触媒や酸化剤等を工夫しても、せいぜい全鉄濃度([T−Fe])が12.5%程度の溶液が得られるにすぎず、反応時間は16時間以上にも達する方法であった。
本発明では、高温高圧法を採用することにより、反応時間の大幅な短縮に成功した。
図1に示す実施例では、全鉄濃度が12.5%の高濃度溶液から全鉄濃度が16%にもなる超高濃度溶液まで、全てのサンプルにおいて30分以内で反応を終了している。反応時間は全鉄濃度に依存することは当然のことで、全鉄濃度が12.5%のものは7.5分で反応が終了し、全鉄濃度が16%のものでも30分以内に反応は終了している。なお、反応の終了は、サンプル溶液中の二価鉄濃度を測定することにより判断した。
このような短時間で反応を行なわせることができることは、従来技術では予想のできない著しく顕著な効果である。
(Reaction time)
The production method according to the prior art described in Patent Document 1 is a method of oxidizing ferrous sulfate at normal temperature and pressure, and even if a catalyst, an oxidizing agent, etc. are devised, the total iron concentration ([T-Fe]) is at most. However, only about 12.5% of the solution was obtained, and the reaction time was 16 hours or more.
In the present invention, the reaction time has been significantly shortened by adopting the high temperature and high pressure method.
In the example shown in FIG. 1, the reaction was completed within 30 minutes in all the samples from the high concentration solution having a total iron concentration of 12.5% to the ultra-high concentration solution having a total iron concentration of 16%. It goes without saying that the reaction time depends on the total iron concentration. The reaction is completed in 7.5 minutes when the total iron concentration is 12.5%, and the reaction is completed within 30 minutes even when the total iron concentration is 16%. ing. The completion of the reaction was determined by measuring the concentration of ferrous iron in the sample solution.
Being able to carry out the reaction in such a short time is a remarkably remarkable effect that cannot be predicted by the prior art.

(超高濃度溶液)
ポリ硫酸第二鉄溶液が超高濃度であるが故の効果を確認するために、次の試料A及び試料Bについて凝集試験を行なった。試料Aは従来技術において16時間以上の時間をかけて製造したものと同じ全鉄濃度を有するサンプルである。一方、試料Bは本発明において製造した全鉄濃度が超高濃度のサンプルである。

Figure 2021053580
(Ultra high concentration solution)
In order to confirm the effect due to the ultra-high concentration of the ferric polysulfate solution, the following sample A and sample B were subjected to an agglutination test. Sample A is a sample having the same total iron concentration as that produced in the prior art over a period of 16 hours or more. On the other hand, sample B is a sample produced in the present invention having an ultra-high total iron concentration.
Figure 2021053580

模擬液としてアクリル絵具の色水を被処理液体とし、添加する試料A及び試料Bの全鉄量が同じくなるように試料Bの添加量を減らし、すなわち、鉄イオンによる凝集能力を同じくして、両者の凝集能力を比較した。
凝集試験の条件を表4に示す。

Figure 2021053580
As a simulated liquid, the colored water of acrylic paint is used as the liquid to be treated, and the amount of sample B added is reduced so that the total amount of iron of sample A and sample B to be added is the same, that is, the aggregation ability by iron ions is the same. The cohesive ability of both was compared.
The conditions of the agglutination test are shown in Table 4.
Figure 2021053580

試料Bは超高濃度であるため、試料Aと同等の凝集能力とする場合には、その添加量を試料Aに比較して32%も減らすことができる。また、試料Bの場合、表1に示されるように[SO4 2-] が低いため、凝集処理後の被処理液のPH低下を抑制することができ、このため、中和のために添加する苛性ソーダの添加量を、試料Aを使用する場合に比較して47%減少することができた。 Since sample B has an ultra-high concentration, the amount of addition thereof can be reduced by 32% as compared with sample A when the agglutination ability is equivalent to that of sample A. Also, in the case of Sample B, due to the low [SO 4 2-] As shown in Table 1, it is possible to suppress the PH lowering of the liquid to be treated after the flocculation treatment, Therefore, it added for neutralization The amount of caustic soda added could be reduced by 47% as compared with the case of using sample A.

また、フロック形成後の様子を観察すると、超高濃度である試料Bの方がフロックの形成能力が高く、フロックの沈降速度も速かった。このように、試料Bは試料Aと鉄量を同じにしているにもかかわらず、試料Bの方が凝集能力が高い。
その理由として考えられるのは、試料Bの方がよりポリマー化しており、フロックの架橋吸着に有利であることである。このことは、試料Bの超高濃度サンプルの方が試料Aよりも液体の粘度が高いことからも裏付けられる。
Moreover, when observing the state after the formation of flocs, the ultra-high concentration sample B had a higher ability to form flocs and a faster settling rate of flocs. As described above, although the sample B has the same amount of iron as the sample A, the sample B has a higher aggregation ability.
A possible reason for this is that sample B is more polymerized and is advantageous for cross-linking adsorption of flocs. This is supported by the fact that the ultra-high concentration sample of sample B has a higher liquid viscosity than sample A.

下水等の廃水処理において利用する凝集剤に関し、凝集性能の高い凝集剤を短時間で製造できるので、排水処理の分野において広く利用することができる。 Regarding the coagulant used in the treatment of wastewater such as sewage, since the coagulant having high coagulation performance can be produced in a short time, it can be widely used in the field of wastewater treatment.

この原因は次の点にあると考えられる。
乾燥機内で50℃に一ヶ月間保持されたサンプル(15.0:32.0)(15.0:34.0)について
、[T−Fe]と[SO42-] を再度測定したところ、それぞれの測定値は、(16.0:34.0
)(16.0:36.0)であった。図3にその内容を示す。
乾燥機内で保持されたサンプルは水分が蒸発して濃縮されたが、濃縮があっても本発明
で規定する領域内の[T−Fe]と[SO42-] の濃度関係を有するサンプルでは殿物は検
出されない。しかし、濃縮により両者の濃度関係が上記領域から逸脱してしまったサンプ
ルでは、濃縮の結果殿物が発生するのである。
このため、(i)の条件下の(15.0:34.0)のサンプルのみに殿物が発生するのである。
The cause of this is considered to be as follows.
When [T-Fe] and [SO42-] were measured again for the samples (15.0: 32.0) (15.0: 34.0) kept at 50 ° C for one month in the dryer, the measured values were (16.0: 34.0:). 34.0
) (16.0: 36.0). The contents are shown in FIG.
The sample held in the dryer was concentrated by evaporating water, but even if it was concentrated, the sample having a concentration relationship of [T-Fe] and [SO42-] in the region specified in the present invention is a feature. Is not detected. However, in the sample in which the concentration relationship between the two deviates from the above region due to the concentration, a lump is generated as a result of the concentration.
For this reason, ridges occur only in the sample under the condition (i) (15.0: 34.0).

Claims (4)

次の条件を満たす硫酸第一鉄と硫酸を含む原料液を密閉容器中で高温高圧条件下で反応させることからなるポリ硫酸第二鉄溶液を含有する鉄系凝集剤の製造方法。
全鉄と硫酸イオンのモル比(SO 2-/T−Fe)が1.2以上
硫酸イオンの重量濃度を[SO 2-] としたときに、[SO 2-]が35重量%以下。
A method for producing an iron-based flocculant containing a polyferric sulfate solution, which comprises reacting ferric sulfate and a raw material solution containing sulfuric acid satisfying the following conditions in a closed container under high temperature and high pressure conditions.
When the molar ratio of total iron and sulfate ion (SO 4 2- / T-Fe ) is a weight concentration of 1.2 or more sulfate ions [SO 4 2-], [SO 4 2-] is 35 wt% Less than.
触媒として、硝酸又は亜硝酸塩を密閉容器中にさらに加えることを特徴とする請求項1の鉄系凝集剤の製造方法。 The method for producing an iron-based flocculant according to claim 1, wherein nitric acid or nitrite is further added to a closed container as a catalyst. 高温高圧の反応条件が、温度100℃以上、圧力0.3MPa以上であることを特徴とする請求項1又は2のいずれかに記載された鉄系凝集剤の製造方法。 The method for producing an iron-based flocculant according to claim 1 or 2, wherein the reaction conditions of high temperature and high pressure are a temperature of 100 ° C. or higher and a pressure of 0.3 MPa or higher. 全鉄濃度が13〜16重量%の高濃度ポリ硫酸第二鉄溶液である鉄系凝集剤。
An iron-based flocculant which is a high-concentration ferric sulfate solution having a total iron concentration of 13 to 16% by weight.
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