JP4330317B2 - Fluorine or phosphorus-containing water treatment equipment - Google Patents

Description

【００３３】
表１に示すとおり、上述の実験１、２、３のいずれにおいても、処理水フッ素濃度として良好な水質が得られた。また、それぞれの実験で生成した晶析物は、含水率が約１０％と従来装置で得られる汚泥に比較して低かった。
【００３４】
「リン除去実験」
種晶としてリン酸カルシウムを約５Ｌ充填した直径＝５０ｍｍ、高さ＝２５００ｍｍの反応槽１０を用い図１のように装置を構成し、リン排水模擬水を通水する実験を行った。
【００３５】
実験４として、リン酸二水素カリウムを１０ｍｇ−Ｐ／Ｌに希釈し、ｐＨ＝５に調整したリン排水模擬水を７９Ｌ／ｈで通水し、晶析剤としてジルコニウム含有率１０％の塩化ジルコニル（ＺｒＯＣｌ_２）溶液を２ｇ−Ｚｒ／ｈで添加した。約１００時間運転して、処理水リン濃度を測定した。
【００３６】
次に、実験５として、晶析剤としてセリウム含有率１０％の塩化セリウム溶液を２ｇ−Ｃｅ／ｈで添加し、その他は実験４と同様の条件で運転し、処理水リン濃度を測定した。
【００３７】
さらに、実験６として、晶析剤としてタンタル含有率１０％の塩化タンタル溶液を２ｇ−Ｔａ／ｈで添加し、その他は実験４と同様の条件で運転し、処理水リン濃度を測定した。
【表２】

【００３８】
このように、実験４、５、６のいずれにおいても、処理水リン濃度として良好な水質が得られた。また、それぞれの実験で生成した晶析物は、含水率が約１０％と従来装置で得られる汚泥に比較して低かった。
【００３９】
【発明の効果】
以上説明したように、本発明によれば、フッ素またはリンと、晶析剤の金属の反応によって、金属フッ化物またはリン酸化合物が生成し、同時に反応槽内の晶析物の周りに晶析する。従って、凝集剤などを使用してフロック化した場合と異なり、生成した粒子は含水率が低く、純度が高い。従って、金属フッ化物としての再利用も可能である。また、汚泥含水率が低く、処分費が安く、かつ処理水フッ素濃度が低いという効果も得られる。
【００４０】
また、処理水の一部を反応槽に循環する循環手段を設けることで、反応槽内の流速を任意に制御することができる。
【００４１】
さらに、被処理水を前記反応槽に上向流で通水し、処理水を反応槽上部から排出することで、晶析物を反応槽内で分離でき沈殿槽などの固液分離装置を別に設ける必要がない。
【図面の簡単な説明】
【図１】 実施形態に係る処理装置の全体構成を示す図である。
【図２】 他の実施形態の構成を示す図である。
【符号の説明】
１０ 反応槽、１２，１８ 流入部、１４ 晶析剤貯槽、１６ 晶析剤注入ポンプ、２０ 越流部、２２ 処理水槽、２４ 循環ポンプ。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for treating fluorine or phosphorus-containing water including a reaction tank that holds a crystallized product in a fluid state.
[0002]
[Prior art]
In the electronics industry that manufactures semiconductors, liquid crystals, and the like, fluorine is often contained in the wastewater from the electronics industry because fluorine is used in the manufacturing process. As a method for removing fluorine discharged from the fluorine-containing water, calcium salt is added to the water to be treated to precipitate calcium fluoride fine particles, and these fine particles are added to an Al, Fe-based inorganic flocculant or A method of aggregating with an organic polymer flocculant and separating by precipitation is employed. According to this method, the treated water fluorine can be reduced to 10 to 20 mg / l. However, in Japan, the emission standard value for fluorine was strengthened from 15 mg / l to 8 mg / l in July 2001, and it became necessary to treat fluorine more highly.
[0003]
As a method for highly treating fluorine, a method of increasing the addition amount of the coagulant in the coagulation precipitation or performing coagulation precipitation one more time after the coagulation precipitation treatment is employed. The amount of the flocculant used in such treatment is 2000 to 5000 mg / l, and fluorine is adsorbed on Al or Fe hydroxide to increase the fluorine removal rate. By this method, the treated water fluorine concentration can be reduced to 2 to 8 mg / l.
[0004]
As another method, it has been proposed to increase the fluorine removal rate by using a hydrous oxide of Zr or Ce on a resin or using a fluorine adsorbent granulated with a polymer substance (Patent Document 1). (Japanese Patent Publication No. 6-79665), Patent Document 2 (Japanese Patent Publication No. Sho 61-47134)). It is said that these methods can reduce the treated water fluorine to 0 to 1 mg / l.
[0005]
Here, the adsorbent is a hydrous oxide MO _n · XH ₂ O (≈M (OH) _m ) generated by adding an alkali to a rare earth element or a salt of Ti or Zr or by heating to hydrolyze. A substance as represented utilizes the property of anion exchange on the acidic side with anions such as PO ₄ ³⁻ , F ⁻ , SO ₄ ²⁻ , and cation exchange on the alkali side (Patent Document 3 JP-B-2-17220), Patent Document 4 (Japanese Patent Laid-Open No. 60-172353)). M is a metal, and X, m, and n are arbitrary numbers.
[0006]
Electronic industry wastewater often contains phosphorus, and phosphorus is also contained in household wastewater. It is necessary to remove phosphorus from the viewpoint of preventing eutrophication in closed waters, and in many areas phosphorus is subject to additional regulations. In the removal of phosphorus, as in the case of fluorine, in addition to the treatment of adding calcium salt to agglomerate and precipitate as calcium phosphate, Al or Fe-based inorganic aggregating agent is used to agglomerate as aluminum phosphate or iron phosphate. Precipitation has been processed. Furthermore, the above adsorbent can treat not only fluorine (F ⁻ ) but also phosphoric acid (PO ₄ ³⁻ ). Therefore, these adsorbents can also be used for phosphorus removal.
[0007]
[Patent Document 1]
Japanese Patent Publication No. 6-79665 [Patent Document 2]
Japanese Patent Publication No. 61-47134 [Patent Document 3]
Japanese Patent Publication No. 2-17220 [Patent Document 4]
Japanese Patent Laid-Open No. 60-172353
[Problems to be solved by the invention]
In the coagulation precipitation method, several thousand mg / l of an Al or Fe type coagulant is added to reduce fluorine. Such agglomerated sludge incorporates water molecules inside the floc, so that the dewaterability of the sludge is poor and the amount of flocculant added is large, resulting in a very large amount of sludge generated. Therefore, there is a problem that the sludge disposal cost increases. In addition, such a process for generating a large amount of waste is a technology that goes against social demands for reducing the amount of waste.
[0009]
On the other hand, although the fluorine adsorbent does not increase sludge, the adsorption rate is slow and the amount of adsorbent used is large. For this reason, there exists a problem that processing cost is very high. There is also a problem that the adsorbent deteriorates due to an oxidizing agent such as hydrogen peroxide contained in the electronics industry wastewater or hydrofluoric acid to be treated, and the base material collapses and flows out.
[0010]
This invention is made | formed in view of the said subject, and it aims at providing the fluorine or phosphorus removal agent or removal method which can remove fluorine and / or phosphorus efficiently from fluorine and / or phosphorus containing water.
[0011]
[Means for Solving the Problems]
The present invention is a treatment apparatus for fluorine- or phosphorus-containing water containing a reaction tank that holds a crystallized substance in a fluid state therein, and water to be treated containing fluorine or phosphorus in the reaction tank, rare earth metal, Ti , Zr, Hf, V, Nb and Ta are separately introduced with a water-soluble compound of at least one metal to bring the treated water into contact with the water-soluble compound, and the fluorine or phosphorus and the water-soluble compound are brought into contact with each other. And a fluorine compound or phosphoric acid compound is crystallized on the surface of the crystallized product to remove fluorine or phosphorus in the water to be treated.
[0012]
Thus, according to the present invention, a metal fluoride or a phosphoric acid compound is generated by the reaction of fluorine or phosphorus and the metal of the crystallization agent, and simultaneously crystallizes around the crystallization product in the reaction vessel. Therefore, unlike the case where the flocculant is made using a flocculant or the like, the generated particles have a low water content and a high purity. Therefore, reuse as a metal fluoride is also possible. Moreover, the effects of low sludge moisture content, low disposal costs, and low concentration of treated water fluorine are also obtained.
[0013]
Further, it is preferable to provide a circulation means for circulating a part of the treated water from the reaction tank to the reaction tank. Thereby, the flow rate in the reaction vessel can be arbitrarily controlled.
[0014]
In addition, it is preferable that the water to be treated is passed upward through the reaction tank and the treated water is discharged from the upper part of the reaction tank. As a result, the crystallization product can be separated in the reaction tank, and there is no need to provide a separate solid-liquid separation device such as a precipitation tank.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an overall configuration of a processing apparatus according to an embodiment. The water to be treated flows into the reaction tank 10 through an inflow member 12 provided in the lower part thereof. This inflow member 12 is a pipe-shaped member having a plurality of openings, whereby the water to be treated is distributed in the lower part in the reaction tank 10. In addition, the reaction tank 10 has a vertically long cylindrical shape and has a hopper shape at the bottom.
[0016]
Further, in the crystallizer storage tank 14, a metal aqueous solution compound that reacts with fluorine or phosphorus in the water to be treated and insolubilizes them is stored, and this is reacted from the inflow member 18 by the crystallizer injection pump 16. It is supplied into the tank 10. The inflow member 18 is disposed slightly above the inflow member 12 and has the same configuration as the inflow member 12.
[0017]
An overflow section 20 is formed at the upper end of the reaction tank 10, and the supernatant liquid that has flowed over the overflow section 20 is discharged as treated water.
[0018]
In the reaction tank 10, the water to be treated and the crystallization agent are mixed in the lower part. The water to be treated contains fluorine or phosphorus, and the crystallization agent is an aqueous solution of a compound of at least one metal among rare earth metals, Ti, Zr, Hf, V, Nb, and Ta. Accordingly, the reaction with fluorine or phosphorus produces an insoluble metal fluoride or metal phosphate compound. The reaction tank 10 has an upward flow due to the incoming water to be treated and the crystallization agent, and the crystallized product is maintained in a fluid state in the reaction tank 10. Therefore, the newly generated insoluble metal fluoride or metal phosphate compound is crystallized on the surface of the crystallized material flowing in the tank. In order to keep the crystallized product in a fluid state, an upward flow linear velocity LV of about 40 m / h is appropriate.
[0019]
Rare earth elements include scandium Sc (atomic number 21), yttrium Y (39) and lanthanum La, cerium Ce, praseodymium Pr, neodymium Nd, promethium Pm, samarium Sm, europium Eu, gadolinium Gd, There are terbium Tb, dysprosium Dy, holmium Ho, erbium Er, thulium Tm, ytterbium Yb, and lutetium Lu, and these chlorides, sulfates, and nitrates can be used as crystallizers. Ti, Zr, Hf, V, Nb and Ta chlorides, sulfates, nitrates, chlorides and sulfates are also used as crystallization agents.
[0020]
In addition, as a seed of the crystallization agent, a crystallization product generated by reacting water to be treated with the crystallization agent, sand, calcium carbonate particles, fluorite, or the like may be added in advance.
[0021]
Moreover, as pH in the reaction tank 10, 3-7 are more suitable, and it is suitable to adjust pH by adding an acid (for example, hydrochloric acid) or an alkali (for example, sodium hydroxide) as needed. is there.
[0022]
Furthermore, if the fluorine concentration and phosphorus concentration in the water to be treated are too high, the amount of crystallized product produced is large, and it becomes expensive compared to coagulation precipitation with a calcium agent, etc., which is not preferable. It is preferable to apply the apparatus of this embodiment to the water to be treated having a fluorine concentration of 20 mg / L or less and a phosphorus concentration of 10 mg / L or less. For high-concentration water to be treated, it is preferable to perform a coagulation sedimentation treatment with a normal calcium agent as a pretreatment and treat the treated water with this apparatus.
[0023]
Thus, in this embodiment, to-be-processed water and a crystallization agent (metal water-soluble compound) are separately injected into the reaction vessel 10. For this reason, in the reaction tank 10, the fluorine and phosphorus insolubilized substance newly produced | generated on the surface of the crystallizing agent used as a seed crystallize efficiently. In the reaction tank 10, the crystallized product is flowing in an upward flow, and is separated into treated water and crystallized product in the upper part of the tank. Therefore, a separate settling tank or the like is unnecessary.
[0024]
In the present embodiment, a metal fluoride or a phosphoric acid compound is generated by the reaction of fluorine or phosphorus and the metal of the crystallizing agent, and at the same time, crystallizes around the crystallized product in the reaction vessel, and grows. Crystallized particles of 1000 μm are formed. Unlike the case where the flocculant is used to flocce, the generated particles have a low water content and a high purity. Therefore, reuse as a metal fluoride is also possible. Moreover, the effects of low sludge moisture content, low disposal costs, and low concentration of treated water fluorine are also obtained.
[0025]
In addition, the crystallized product continues to grow as the process continues. Therefore, it is necessary to discharge the crystallized substance at an appropriate frequency. In this case, it is preferable to provide a discharge drain at the bottom and discharge the slurry in the form of a slurry. Further, it may be discharged from above with a pump or the like.
[0026]
FIG. 2 shows the configuration of another embodiment. In this apparatus, it has the treated water tank 22 and the circulation pump 24, and the treated water obtained from the upper part of the reaction tank 10 is once stored in the treated water tank 22, and discharged from here. A part of the treated water in the treated water tank 22 is circulated to the bottom of the reaction tank 10 by a circulation pump 24. Thereby, the linear velocity LV of the upward flow in the reaction tank 10 can be arbitrarily set regardless of the flow rate of the water to be treated, and the flow state of the crystallized substance in the reaction tank 10 is always maintained appropriately. Becomes easier.
[0027]
The present invention can also be suitably applied to waste water containing both fluorine and phosphorus. In this case, an equivalent or more zirconyl salt may be added with respect to the total amount of fluorine and phosphorus.
[0028]
【Example】
"Fluorine removal experiment"
An apparatus was constructed as shown in FIG. 1 using a reaction vessel 10 having a diameter = 50 mm and a height = 2500 mm filled with about 5 L of fluorite as a seed crystal, and an experiment was conducted to pass simulated fluorine drainage water.
[0029]
In Experiment 1, sodium fluoride was diluted to 20 mg-F / L, simulated drainage of fluorine drainage adjusted to pH = 5 was passed at 79 L / h, and chlorinated with a zirconium content of 10% as a crystallization agent. Zirconium oxide solution was added at 4 g-Zr / h. After operating for about 100 hours, the fluorine concentration of the treated water was measured.
[0030]
Next, as Experiment 2, a cerium chloride solution having a cerium content of 10% was added as a crystallization agent at 4 g-Ce / h, and the others were operated under the same conditions as in Experiment 1, and the treated water fluorine concentration was measured.
[0031]
Further, as Experiment 3, a tantalum chloride solution having a tantalum content of 10% was added as a crystallization agent at 4 g-Ta / h, and the others were operated under the same conditions as in Experiment 1 to measure the fluorine concentration in the treated water.
[0032]
Table 1 shows the results of these experiments.
[Table 1]

[0033]
As shown in Table 1, in any of the above-described Experiments 1, 2, and 3, good water quality was obtained as the treated water fluorine concentration. In addition, the crystallized product produced in each experiment had a water content of about 10%, which was lower than the sludge obtained with the conventional apparatus.
[0034]
"Phosphorus removal experiment"
An apparatus was constructed as shown in FIG. 1 using a reaction tank 10 having a diameter = 50 mm and a height = 2500 mm filled with about 5 L of calcium phosphate as a seed crystal, and an experiment was conducted to pass phosphorus simulated drainage water.
[0035]
In Experiment 4, phosphorus simulated waste water diluted with potassium dihydrogen phosphate to 10 mg-P / L and adjusted to pH = 5 was passed at 79 L / h, and zirconyl chloride having a zirconium content of 10% was used as a crystallization agent. (ZrOCl ₂ ) solution was added at 2 g-Zr / h. After operating for about 100 hours, the concentration of treated water phosphorus was measured.
[0036]
Next, as Experiment 5, a cerium chloride solution having a cerium content of 10% was added as a crystallization agent at 2 g-Ce / h, and the others were operated under the same conditions as in Experiment 4, and the concentration of treated water phosphorus was measured.
[0037]
Further, as Experiment 6, a tantalum chloride solution having a tantalum content of 10% was added as a crystallization agent at 2 g-Ta / h, and the others were operated under the same conditions as in Experiment 4 to measure the concentration of treated water phosphorus.
[Table 2]

[0038]
Thus, in any of Experiments 4, 5, and 6, good water quality was obtained as the treated water phosphorus concentration. In addition, the crystallized product produced in each experiment had a water content of about 10%, which was lower than the sludge obtained with the conventional apparatus.
[0039]
【The invention's effect】
As described above, according to the present invention, a metal fluoride or a phosphoric acid compound is produced by the reaction of fluorine or phosphorus and the metal of the crystallization agent, and at the same time, the crystallization occurs around the crystallization product in the reaction vessel. To do. Therefore, unlike the case where the flocculant is made using a flocculant or the like, the generated particles have a low water content and a high purity. Therefore, reuse as a metal fluoride is also possible. Moreover, the effect that the sludge moisture content is low, the disposal cost is low, and the fluorine concentration of the treated water is low is also obtained.
[0040]
Moreover, the flow rate in a reaction tank can be arbitrarily controlled by providing the circulation means which circulates a part of treated water to a reaction tank.
[0041]
Furthermore, the water to be treated is passed through the reaction tank in an upward flow, and the treated water is discharged from the upper part of the reaction tank, so that the crystallized product can be separated in the reaction tank. There is no need to provide it.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an overall configuration of a processing apparatus according to an embodiment.
FIG. 2 is a diagram showing a configuration of another embodiment.
[Explanation of symbols]
10 reaction tanks, 12, 18 inflow part, 14 crystallization agent storage tank, 16 crystallization agent injection pump, 20 overflow part, 22 treated water tank, 24 circulation pump.

Claims (4)

An apparatus for treating fluorine-containing or phosphorus-containing water including a reaction tank that holds a crystallized substance in a fluid state therein,
The water to be treated containing fluorine or phosphorus and a water-soluble compound of at least one metal selected from rare earth metals, Ti, Zr, Hf, V, Nb, and Ta are separately introduced into the reaction tank, and the water is removed. Treated water and the water-soluble compound are contacted, the fluorine or phosphorus and the water-soluble compound are reacted, and a fluoride or phosphoric acid compound is crystallized on the surface of the crystallized product, An apparatus for treating fluorine or phosphorus-containing water, wherein fluorine or phosphorus is removed. The apparatus of claim 1.
A treatment apparatus for fluorine- or phosphorus-containing water, comprising a circulation means for circulating a part of the treated water from the reaction tank to the reaction tank. The apparatus according to claim 1 or 2,
The water to be treated was passed water upflow in the reactor, the processing apparatus of fluorine or phosphorus-containing water, which comprises discharging the treated water from the reactor top. The device according to any one of claims 1 to 3,
  A treatment apparatus for fluorine or phosphorus-containing water, wherein the pH in the reaction vessel is adjusted to 3 to 7.

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