JP5242061B2 - Method and apparatus for obtaining purified phosphoric acid from aqueous phosphoric acid solution containing a plurality of metal ions - Google Patents

Method and apparatus for obtaining purified phosphoric acid from aqueous phosphoric acid solution containing a plurality of metal ions Download PDF

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JP5242061B2
JP5242061B2 JP2007028820A JP2007028820A JP5242061B2 JP 5242061 B2 JP5242061 B2 JP 5242061B2 JP 2007028820 A JP2007028820 A JP 2007028820A JP 2007028820 A JP2007028820 A JP 2007028820A JP 5242061 B2 JP5242061 B2 JP 5242061B2
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phosphoric acid
aqueous solution
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metal ions
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JP2008189537A (en
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正吾 前田
友潔 竹山
昭昌 小田
榮一 水谷
泰人 川瀬
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日本リファイン株式会社
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    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23FNON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00Etching metallic material by chemical means
    • C23F1/46Regeneration of etching compositions
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00Phosphorus; Compounds thereof
    • C01B25/16Oxyacids of phosphorus; Salts thereof
    • C01B25/18Phosphoric acid

Description

金属エッチング工程などで使用されている硝酸−酢酸−リン酸の混合水溶液(以下、混酸水溶液という)では、エッチングでの使用限度(重量基準で500〜1000ppm程度)以上の金属イオンを含む廃液が排出される。本発明は、このような複数の金属イオンを含む混酸水溶液(以下、混酸水溶液廃液という)などから金属イオンを除去し、精製リン酸を得る方法及び装置に関する。特に、溶融晶析法・溶媒抽出法などにより1次処理を行って得た残りの(現在は廃棄処分されている)、金属イオンを高濃度、即ち、重量基準で500ppm〜金属イオンとしてリン酸水溶液に溶解する上限まで含むリン酸水溶液の処理に適した方法及び装置に関する。 In a mixed aqueous solution of nitric acid-acetic acid-phosphoric acid (hereinafter referred to as a mixed acid aqueous solution) used in metal etching processes, etc., waste liquid containing metal ions exceeding the usage limit for etching (about 500 to 1000 ppm by weight) is discharged. Is done. The present invention relates to a method and an apparatus for obtaining purified phosphoric acid by removing metal ions from such a mixed acid aqueous solution containing a plurality of metal ions (hereinafter referred to as a mixed acid aqueous solution waste liquid). In particular, the remaining metal ion obtained by the primary treatment by the melt crystallization method, the solvent extraction method, etc. (currently disposed of) is phosphoric acid in a high concentration , that is, 500 ppm to metal ion on a weight basis. the upper limit is dissolved in an aqueous solution or in a method and apparatus suitable for processing including phosphoric acid aqueous solution.
半導体製造工場や液晶ディスプレイ製造におけるAlなどの金属エッチング工程では、混酸水溶液新液として、例えば、リン酸、硝酸、酢酸、水の混合物が用いられているが、含有される総金属イオン濃度は100ppb以下である。しかし、この混酸水溶液は、使用するに従い金属の溶解が進み、金属イオン濃度が上昇すると共に、揮発性物質(硝酸、酢酸、水)の蒸発や被エッチング材への付着などにより組成が変化し、エッチング能力が低下するため、一部又は全部を新液と交換して、総金属イオン濃度を低く抑える(重量基準で500〜1000ppm程度以下)と共に、組成の変化を抑制してエッチング能力を維持するようにしている。そこで、排出される混酸水溶液廃液から金属イオンを除去すると共に混酸水溶液を高収率で回収する処理装置が求められている。
Al金属エッチング装置から排出される混酸水溶液廃液を精製する最初の段階は、蒸発又は蒸留法により揮発性物質(硝酸、酢酸、水の大部分)を蒸発させて分離することである。リン酸と金属イオンは共に非揮発性物質であるから、この蒸発又は蒸留では分離できない。この段階でのリン酸(以下、濃縮リン酸という)は濃度約90重量%であり、水を約10重量%含む。
In metal etching processes such as Al in semiconductor manufacturing factories and liquid crystal display manufacturing, for example, a mixture of phosphoric acid, nitric acid, acetic acid, and water is used as a new mixed acid aqueous solution, but the total metal ion concentration contained is 100 ppb. It is as follows. However, as this mixed acid aqueous solution is used, the dissolution of metals progresses, the concentration of metal ions increases, and the composition changes due to evaporation of volatile substances (nitric acid, acetic acid, water) and adhesion to the material to be etched. Since the etching ability is reduced, a part or all of it is replaced with a new solution to keep the total metal ion concentration low (about 500 to 1000 ppm or less by weight) and to keep the etching ability by suppressing the change in composition. I am doing so. Accordingly, there is a need for a treatment apparatus that removes metal ions from the discharged mixed acid aqueous solution waste liquid and recovers the mixed acid aqueous solution with high yield.
The first stage of purifying the mixed acid waste solution discharged from the Al metal etching apparatus is to evaporate and separate volatile substances (most of nitric acid, acetic acid and water) by evaporation or distillation. Since phosphoric acid and metal ions are both non-volatile substances, they cannot be separated by this evaporation or distillation. The phosphoric acid at this stage (hereinafter referred to as concentrated phosphoric acid) has a concentration of about 90% by weight and contains about 10% by weight of water.
溶液中に存在する金属イオンを分離する一般的な方法として、イオン交換樹脂法、拡散透析法、隔膜電気透析法、電気透析法、活性炭による吸着法がある。しかし、これらの方法を混酸水溶液廃液又は濃縮リン酸に適用しても、高濃度のリン酸は腐食性が強いこと、金属イオンとしてアニオン、カチオンの両方を含むこと、更に次のような問題が発生することから、金属イオンを十分に分離することは出来ない。
イオン交換樹脂法では、高濃度の酸に溶解している金属イオンをイオン交換することは困難である。また樹脂の再生効率が低いことが分った。拡散透析法では、得られるリン酸が希釈され、また大量の透析残液が発生する。隔膜電気透析法では、混酸水溶液廃液中の硝酸の酸化によるNOx発生が問題となる。電気透析法では、リン酸イオンとモリブデン酸イオンのイオン半径が近似していて移動速度が同等であるため分離できない。活性炭による吸着法では、混酸水溶液廃液が活性炭により着色してしまう。
Common methods for separating metal ions present in a solution include an ion exchange resin method, a diffusion dialysis method, a diaphragm electrodialysis method, an electrodialysis method, and an adsorption method using activated carbon. However, even if these methods are applied to mixed acid aqueous solution waste liquid or concentrated phosphoric acid, high concentrations of phosphoric acid are highly corrosive, contain both anions and cations as metal ions, and have the following problems. Since it is generated, metal ions cannot be sufficiently separated.
In the ion exchange resin method, it is difficult to ion exchange metal ions dissolved in a high concentration acid. It was also found that the resin regeneration efficiency was low. In the diffusion dialysis method, the obtained phosphoric acid is diluted and a large amount of dialysis residue is generated. In the diaphragm electrodialysis method, NOx generation due to oxidation of nitric acid in the mixed acid aqueous solution waste solution becomes a problem. The electrodialysis method cannot be separated because the ionic radii of phosphate ions and molybdate ions are approximate and the moving speeds are equal. In the adsorption method using activated carbon, the mixed acid aqueous solution waste liquid is colored by activated carbon.
一方、濃縮リン酸の精製方法の一つとして金属抽出剤法(特許文献1)がある。しかしMoは減らせたがAlの減量は捗々しくなかった。また、濃縮リン酸中の金属に陽イオン(Al3+など)と、陰イオン(MoO 2−など金属が酸化された形態のもの)が溶解していると、両方のイオンを減らすため、抽出塔と逆抽出塔が陽イオン用と陰イオン用の2セット必要となり、多大な設備費用が掛かる上に、運転経費の上昇も予想され、リン酸を再利用するメリットを出すことは難しい。
他の濃縮リン酸液の精製方法としては晶析法(特許文献2〜3)があるが、何れもバッチ処理法であり、微妙な温度制御が必要で処理時間が長いなど問題がある。
更に他の濃縮リン酸の精製方法として晶析法(非特許文献1)がある。しかし、この方法を濃縮リン酸に適用した場合、リン酸半水結晶の精製純度は母液金属濃度に依存するため、品質的に収率は約80重量%程度が限界であり、資源有効利用の点から更に収率をアップすることが望まれる。
On the other hand, there is a metal extractant method (Patent Document 1) as one of methods for purifying concentrated phosphoric acid. However, although Mo could be reduced, the weight loss of Al was not gradual. Also, if cations (Al 3+, etc.) and anions (a form in which metal is oxidized, such as MoO 4 2− ) are dissolved in the metal in concentrated phosphoric acid, extraction is performed to reduce both ions. Two sets of towers and back-extraction towers for cation and anion are required, which entails considerable equipment costs and an increase in operating expenses, making it difficult to recycle phosphoric acid.
There are crystallization methods (Patent Documents 2 to 3) as other purification methods for the concentrated phosphoric acid solution, but they are all batch processing methods, and there are problems such as requiring delicate temperature control and long processing time.
Furthermore, there exists a crystallization method (nonpatent literature 1) as another purification method of concentrated phosphoric acid. However, when this method is applied to concentrated phosphoric acid, the purification purity of phosphoric acid hemihydrate crystals depends on the concentration of the mother liquor metal, so the yield is limited to about 80% by weight in terms of quality. From this point, it is desired to further increase the yield.
本発明に関連する共沈については、非特許文献2に次のように記載されている。
「共沈とは、ある沈殿物が沈殿するとき、可溶性の物質がそれに伴って沈殿する現象をいう。共沈現象は、混晶の生成によって起こることもあり、沈殿の生成過程でイオンが吸着されるために起こることもある。前者の場合は不純物が沈殿物の結晶格子の中に実際に入り込む。後者の場合は、吸着されたイオンが凝析の過程で沈殿物に引きずられてしまう現象である。」
しかし、非特許文献2は一般的な共沈現象について説明しているだけであり、本発明のような濃縮リン酸中の金属イオンの共沈については全く記載されていない。
The coprecipitation related to the present invention is described in Non-Patent Document 2 as follows.
“Co-precipitation is a phenomenon in which a soluble substance precipitates when a certain precipitate is precipitated. Co-precipitation may occur due to the formation of a mixed crystal, and ions are adsorbed during the formation of the precipitate. In the former case, impurities actually enter the crystal lattice of the precipitate, and in the latter case, the adsorbed ions are dragged by the precipitate during the coagulation process. Is. "
However, Non-Patent Document 2 only describes a general coprecipitation phenomenon, and does not describe coprecipitation of metal ions in concentrated phosphoric acid as in the present invention.
特願2005−142444号Japanese Patent Application No. 2005-142444 特願2004−255388号Japanese Patent Application No. 2004-255388 特許第3382561号公報Japanese Patent No. 3382561
従来、金属エッチング工程で排出される複数の金属イオンを含んだ混酸水溶液廃液は、金属イオン濃度の上昇に伴いエッチング能力が低下するため廃棄処分していた。
そこで、本発明では、複数の金属イオンを含むリン酸水溶液から金属イオンを分離除去して精製リン酸を得る方法及び装置の提供、更には、金属エッチング工程で排出される高濃度のリン酸を含む混酸水溶液廃液に応用することにより、回収した精製リン酸を再利用するシステムの提供を目的とする。
Conventionally, mixed acid aqueous solution waste liquid containing a plurality of metal ions discharged in the metal etching process has been discarded because the etching ability decreases with increasing metal ion concentration.
Therefore, in the present invention, a method and an apparatus for obtaining purified phosphoric acid by separating and removing metal ions from a phosphoric acid aqueous solution containing a plurality of metal ions, and further, high-concentration phosphoric acid discharged in the metal etching step are provided. It aims at providing the system which reuses the collect | recovered purified phosphoric acid by applying to the mixed acid aqueous solution waste liquid containing.
上記課題は、次の1)〜8)の発明によって解決される。
1) 〔1〕複数の金属イオンを含むリン酸水溶液に無機塩水溶液を混合し、次いでリン酸に可溶でかつ無機塩を溶解しない有機溶媒(以下、貧溶媒という)を加えて混合することにより無機塩の結晶を析出させると同時に、前記金属イオンを共沈させた後、該金属イオンを含む無機塩の結晶を濾過して固液分離する工程、
〔2〕濾過した濾液中の貧溶媒及び水を蒸発させる工程、
を含むことを特徴とする精製リン酸を得る方法。
2) 〔1〕〔2〕の工程を複数回繰り返すことを特徴とする1)記載の精製リン酸を得る方法。
3) 複数の金属イオンを含むリン酸水溶液が、重量基準で500ppm〜金属イオンとしてリン酸水溶液に溶解する上限までの金属イオンを含むことを特徴とする1)又は2)記載の精製リン酸を得る方法。
4) 金属イオンを共沈させ濾過した無機塩の結晶を温水で溶解し、次いで、無機塩の結晶を析出させ、共沈していた金属を無機塩から分離した後、濾過して無機塩を回収し再利用することを特徴とする1)〜3)の何れかに記載の精製リン酸を得る方法。
5) 少なくとも、無機塩を溶解する機能を有する無機塩溶解槽、複数の金属イオンを含むリン酸水溶液と貧溶媒と無機塩水溶液を混合するための攪拌機を具備した晶析・共沈槽、無機塩結晶の濾過装置、及び、濾液から貧溶媒と水を蒸発させるための加熱設備を具備した有機溶媒蒸発装置を有することを特徴とする1)〜3)の何れかに記載の方法を実施するための装置。
6) 濾過した無機塩の結晶を温水で溶解し再度結晶を析出させるための無機塩精製晶析槽、及び、析出させた無機塩の結晶を分離するための濾過装置を有することを特徴とする5)記載の装置。
7) 金属エッチング装置、エッチング後液を貯留する混酸水溶液タンク、混酸水溶液廃液タンク、混酸水溶液廃液から硝酸・酢酸・水を蒸発させて留去する装置(蒸発装置)、及び5)又は6)記載の装置を有し、混酸水溶液を再利用するように設計されていることを特徴とする金属のエッチングシステム。
8) 更に、前記蒸発装置で硝酸・酢酸・水を留去した後の濃縮リン酸の溶融晶析装置を有することを特徴とする7)記載の金属のエッチングシステム。
The above problems are solved by the following inventions 1) to 8).
1) [1] An inorganic salt aqueous solution is mixed with a phosphoric acid aqueous solution containing a plurality of metal ions, and then an organic solvent that is soluble in phosphoric acid and does not dissolve the inorganic salt (hereinafter referred to as a poor solvent) is added and mixed. The step of precipitating inorganic salt crystals and co-precipitating the metal ions, followed by filtering the inorganic salt crystals containing the metal ions to separate into solid and liquid,
[2] a step of evaporating the poor solvent and water in the filtered filtrate;
A method for obtaining purified phosphoric acid comprising
2) The method of obtaining the purified phosphoric acid according to 1), wherein the steps [1] and [2] are repeated a plurality of times.
3) phosphoric acid aqueous solution containing a plurality of metal ions, purification phosphorus Weight 1, characterized in that it comprises a metal ion at the upper limit or criteria in dissolved in phosphoric acid aqueous solution as 500ppm~ metal ions) or 2), wherein How to get acid.
4) The inorganic salt crystals co-precipitated and filtered with metal ions are dissolved in warm water, and then the inorganic salt crystals are precipitated. The coprecipitated metal is separated from the inorganic salt, and then filtered to remove the inorganic salt. The method for obtaining the purified phosphoric acid according to any one of 1) to 3), wherein the purified phosphoric acid is recovered and reused.
5) At least an inorganic salt dissolution tank having a function of dissolving an inorganic salt, a crystallization / coprecipitation tank equipped with a stirrer for mixing a phosphoric acid aqueous solution containing a plurality of metal ions, a poor solvent and an inorganic salt aqueous solution, inorganic The method according to any one of 1) to 3), which comprises a salt crystal filtration device and an organic solvent evaporation device equipped with a heating facility for evaporating the poor solvent and water from the filtrate. Equipment for.
6) It is characterized by having an inorganic salt refining crystallization tank for dissolving a filtered inorganic salt crystal with warm water and precipitating the crystal again, and a filtration device for separating the precipitated inorganic salt crystal. 5) The apparatus described.
7) Metal etching apparatus, mixed acid aqueous solution tank for storing the solution after etching, mixed acid aqueous solution waste tank, apparatus for evaporating nitric acid / acetic acid / water from the mixed acid aqueous solution waste liquid (evaporation apparatus), and 5) or 6) A metal etching system, characterized in that it is designed to reuse a mixed acid aqueous solution.
8) The metal etching system according to 7), further comprising a melt crystallizer for concentrated phosphoric acid after the nitric acid, acetic acid and water are distilled off by the evaporator.
以下、上記本発明について詳しく説明する。
本発明者等は、鋭意研究を行った結果、高濃度、即ち、重量基準で500ppm〜金属イオンとしてリン酸水溶液に溶解する上限までの金属イオンを含むリン酸水溶液に対して特に有効な、晶析・共沈現象を利用することにより金属イオンを分離除去し精製リン酸を得る方法及び装置を見出し、更に金属エッチング工程における複数の金属イオンを含む濃縮リン酸に応用すれば、リン酸を高収率で回収して再利用できることを見出した。なお、本発明でいう精製リン酸とは、金属イオンを分離除去したリン酸のことであり、リン酸の濃度は90重量%程度である。
処理対象となるリン酸水溶液中の金属イオン濃度は重量基準で500ppm程度以上が好ましい。本発明では金属イオンを晶析・共沈させるのに無機塩を用いるが、除去対象の金属イオンの濃度が低くなると、晶析・共沈、固液分離後の濾液中に含まれる陽イオンのうち、無機塩を構成する陽イオンの占める割合が大きくなり、除去したい金属イオンと無機塩の陽イオンとを交換したに過ぎないことになってしまうので、本発明の効果が得難くなる。
また、処理対象となるリン酸水溶液中のリン酸濃度は約90重量%以上が好ましい。リン酸濃度が低いと水の割合が増えるため、水に溶けた無機塩中の陽イオンが濾液中に多く残ることになり、本発明の効果が得にくくなる。
Hereinafter, the present invention will be described in detail.
The present inventors, as a result of intense study, high concentration, i.e., particularly effective against phosphate aqueous solution containing metal ions in the upper or dissolved in phosphoric acid aqueous solution as 500ppm~ metal ions by weight, Finding a method and apparatus for obtaining purified phosphoric acid by separating and removing metal ions by utilizing crystallization / coprecipitation phenomenon, and further applying phosphoric acid to concentrated phosphoric acid containing multiple metal ions in the metal etching process. It was found that it can be recovered and reused in high yield. The purified phosphoric acid referred to in the present invention is phosphoric acid from which metal ions have been separated and removed, and the concentration of phosphoric acid is about 90% by weight.
The metal ion concentration in the phosphoric acid aqueous solution to be treated is preferably about 500 ppm or more by weight. In the present invention, an inorganic salt is used to crystallize and coprecipitate metal ions. However, when the concentration of metal ions to be removed decreases, the cation contained in the filtrate after crystallization and coprecipitation and solid-liquid separation. Among them, the proportion of the cation constituting the inorganic salt is increased, and the metal ion to be removed and the cation of the inorganic salt are merely exchanged, so that it is difficult to obtain the effect of the present invention.
The phosphoric acid concentration in the phosphoric acid aqueous solution to be treated is preferably about 90% by weight or more. If the phosphoric acid concentration is low, the proportion of water increases, so that a large amount of cations in the inorganic salt dissolved in water remain in the filtrate, making it difficult to obtain the effects of the present invention.
本発明の実施形態例として、金属エッチング工程で排出される複数の金属イオンを含む混酸水溶液廃液を処理する方法及び装置について、図面を参照しつつ説明する。
図1は、金属エッチング工程の装置の概要を示す図であり、エッチング液受槽を備えたエッチングを行なう部分、混酸水溶液タンク、混酸水溶液廃液タンク、本発明に係る混酸水溶液精製装置、及びこれらを結ぶ配管などからなる。工程の流れは次の通りである。
まず混酸水溶液新液を混酸水溶液タンクに供給し、次いで、混酸水溶液タンクから混酸水溶液を汲み上げ、シャワーリングしながら被エッチング材をエッチングする。
エッチングを終えた混酸水溶液は、エッチング液受槽を経てエッチング後液として混酸水溶液タンクに戻す。
混酸水溶液新液を混酸水溶液廃液タンクに供給した際に、混酸水溶液タンクから溢れた混酸水溶液を、混酸水溶液廃液として混酸水溶液廃液タンクに移送する。
混酸水溶液廃液タンクに集めた混酸水溶液廃液を、混酸水溶液精製装置に供給し、エッチングの際に混酸水溶液に溶解した金属イオンを晶析・共沈法により分離精製し、処理済の混酸水溶液を回収して混酸水溶液タンクに戻す。一部は廃液として排出する。
As an embodiment of the present invention, a method and apparatus for treating a mixed acid aqueous solution waste solution containing a plurality of metal ions discharged in a metal etching step will be described with reference to the drawings.
FIG. 1 is a view showing an outline of an apparatus for a metal etching process, and includes an etching portion equipped with an etching solution receiving tank, a mixed acid aqueous solution tank, a mixed acid aqueous solution waste liquid tank, a mixed acid aqueous solution purifying device according to the present invention, and connecting them. It consists of piping. The process flow is as follows.
First, a new mixed acid aqueous solution is supplied to the mixed acid aqueous solution tank, then the mixed acid aqueous solution is pumped from the mixed acid aqueous solution tank, and the material to be etched is etched while showering.
After the etching, the mixed acid aqueous solution is returned to the mixed acid aqueous solution tank as a post-etching solution through an etching solution receiving tank.
When the new mixed acid aqueous solution is supplied to the mixed acid aqueous solution waste tank, the mixed acid aqueous solution overflowing from the mixed acid aqueous solution tank is transferred to the mixed acid aqueous solution waste tank as the mixed acid aqueous solution waste.
The mixed acid aqueous solution waste liquid collected in the mixed acid aqueous solution waste tank is supplied to the mixed acid aqueous solution purification device, and metal ions dissolved in the mixed acid aqueous solution are separated and purified by crystallization and coprecipitation during etching, and the treated mixed acid aqueous solution is recovered. Return to the mixed acid solution tank. Some are discharged as waste liquid.
図2は、混酸水溶液精製装置の一部である蒸発装置の概要を示す図である。蒸発装置は一般的なものでよいが、リン酸の粘性が高いため薄膜流下式蒸発装置が望ましい。装置の操作・機能は次の通りである。
まず図1の混酸水溶液廃液タンクから供給される混酸水溶液廃液をリボイラーを介して液受槽に供給する。
次いで、系内を2000〜7000Pa程度の減圧に保持し、ポンプにより混酸水溶液廃液を液受槽とリボイラーの間で循環させながら、リボイラーにスチームを通して混酸水溶液廃液を加熱し、硝酸・酢酸・水を蒸発させて留去する。
留去した硝酸・酢酸・水は、冷却水を通したコンデンサーで凝縮し、留出液受けに貯留した後、エッチング液濃度調整の原料として再利用する。
硝酸・酢酸・水を留去した濃縮リン酸は、晶析・共沈工程又は溶融晶析工程へ移送する。
FIG. 2 is a diagram showing an outline of an evaporation apparatus which is a part of the mixed acid aqueous solution purification apparatus. Although a general evaporator may be used, a thin film flow-down evaporator is desirable because of high viscosity of phosphoric acid. The operation and functions of the device are as follows.
First, the mixed acid aqueous solution waste liquid supplied from the mixed acid aqueous solution waste tank shown in FIG. 1 is supplied to the liquid receiving tank through the reboiler.
Next, the system is maintained at a reduced pressure of about 2000 to 7000 Pa, and while the mixed acid aqueous solution waste liquid is circulated between the liquid receiving tank and the reboiler by the pump, the mixed acid aqueous solution waste liquid is heated through steam through the reboiler to evaporate nitric acid / acetic acid / water. And distill off.
The distilled nitric acid, acetic acid, and water are condensed in a condenser through which cooling water is passed, stored in a distillate receiver, and then reused as a raw material for adjusting the etching solution concentration.
The concentrated phosphoric acid from which nitric acid, acetic acid and water have been distilled off is transferred to a crystallization / coprecipitation step or a melt crystallization step.
図3は、本発明に係る精製リン酸を得る装置を金属エッチング装置のオンライン上に組み込んだ金属エッチング液リサイクルシステムの一例の概要を説明する図である。
エッチング装置及び蒸発装置はそれぞれ図1、図2で説明したのと同様の装置である。特に説明がない限り、操作温度及び圧力は常温・常圧である。
前述したように、エッチング装置から排出された混酸水溶液廃液を蒸発装置に移送し、濃縮リン酸と留出液(硝酸・酢酸・水)とに分離する。
留出液はエッチング液濃度調製装置に移送し再利用する。
濃縮リン酸は晶析・共沈槽に移送し、無機塩溶解槽で予め混合しておいた無機塩水溶液と混合する。無機塩としては、リン酸二水素ナトリウム、リン酸二水素カリウム、リン酸二水素アンモニウム、リン酸マグネシウムなどのリン酸塩、或いは硫酸ナトリウム、硫酸アンモニウムなどの硫酸塩、酢酸ナトリウム、酢酸アンモニウムなどの酢酸塩などが挙げられるが、リン酸塩、硫酸塩が好ましい。
十分に混合したら、貧溶媒を添加し、無機塩の結晶を析出させると共に、濃縮リン酸中の金属を共沈させる。貧溶媒の量は、容量比でリン酸の2〜10倍、好ましくは3〜5倍程度とする。貧溶媒としては、アルコール類、ケトン類など、無機塩を0.1重量%未満程度しか溶解しないものを用いる必要がある。具体例としてはイソプロピルアルコール(以下、IPAという)、イソブタノール、アセトン、メチルイソブチルケトンなどが挙げられる。
晶析・共沈が完了したら、スラリーを濾過装置へ移送し固液分離を行う。濾過装置は、フィルタープレス又はヌッチェ式濾過器が好ましい。
なお、無機塩や貧溶媒の種類とその添加量は、濃縮リン酸中の金属イオン濃度により適宜決めればよい。
FIG. 3 is a diagram for explaining an outline of an example of a metal etchant recycling system in which an apparatus for obtaining purified phosphoric acid according to the present invention is incorporated on-line of a metal etching apparatus.
The etching apparatus and the evaporation apparatus are the same apparatuses as described with reference to FIGS. Unless otherwise specified, the operating temperature and pressure are normal temperature and normal pressure.
As described above, the mixed acid aqueous solution waste liquid discharged from the etching apparatus is transferred to the evaporation apparatus and separated into concentrated phosphoric acid and distillate (nitric acid / acetic acid / water).
The distillate is transferred to the etching solution concentration adjusting device and reused.
Concentrated phosphoric acid is transferred to a crystallization / coprecipitation tank and mixed with an aqueous inorganic salt solution previously mixed in an inorganic salt dissolution tank. Inorganic salts include phosphates such as sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, and magnesium phosphate, or sulfates such as sodium sulfate and ammonium sulfate, and acetic acid such as sodium acetate and ammonium acetate. Examples of the salt include phosphates and sulfates.
Once mixed well, a poor solvent is added to precipitate inorganic salt crystals and coprecipitate the metal in the concentrated phosphoric acid. The amount of the poor solvent is about 2 to 10 times, preferably about 3 to 5 times that of phosphoric acid by volume ratio. As the poor solvent, it is necessary to use a solvent that dissolves an inorganic salt of less than about 0.1% by weight, such as alcohols and ketones. Specific examples include isopropyl alcohol (hereinafter referred to as IPA), isobutanol, acetone, methyl isobutyl ketone and the like.
When crystallization and coprecipitation are completed, the slurry is transferred to a filtration device and solid-liquid separation is performed. The filter device is preferably a filter press or a Nutsche filter.
In addition, what kind of inorganic salt and poor solvent and the addition amount thereof may be appropriately determined depending on the metal ion concentration in the concentrated phosphoric acid.
濾過装置を通った濾液(リン酸、貧溶媒、水の混合物)は有機溶媒蒸発装置へ移送し、貧溶媒と水を留去する。貧溶媒は、有機溶媒脱水装置で脱水精製した後、晶析・共沈槽で再利用する。
貧溶媒を留去した精製リン酸は、エッチング液濃度調整装置で前記蒸発装置留出液と混合し、混酸水溶液新液と同程度となるように不足成分を補充して、リサイクル混酸水溶液としてエッチング装置で循環使用する。
本発明の方法及び装置は、溶融晶析法・溶媒抽出法などで比較的低濃度(重量基準で500ppm未満)の金属イオンを1次処理したのち廃棄される高濃度、即ち、重量基準で500ppm〜金属イオンとしてリン酸水溶液に溶解する上限までの金属イオンを含むリン酸水溶液の処理に好適である。
The filtrate (a mixture of phosphoric acid, poor solvent and water) that has passed through the filtration device is transferred to an organic solvent evaporation device, and the poor solvent and water are distilled off. The poor solvent is dehydrated and purified by an organic solvent dehydrator and then reused in a crystallization / coprecipitation tank.
Purified phosphoric acid from which the poor solvent has been distilled off is mixed with the above-mentioned evaporator distillate with an etching solution concentration adjusting device, supplemented with insufficient components so as to be about the same as the new mixed acid aqueous solution, and etched as a recycled mixed acid aqueous solution. Recycle in equipment.
The method and apparatus of the present invention is a high concentration that is discarded after the primary treatment of metal ions having a relatively low concentration (less than 500 ppm on a weight basis) by a melt crystallization method, a solvent extraction method , or the like, that is, 500 ppm on a weight basis. ~ is suitable aqueous solution of phosphoric acid processes including metal ions in the upper dissolved in phosphoric acid aqueous solution or as a metal ion.
濾過装置残渣(含共沈金属無機塩)は、水を供給(図示せず)して溶解し、無機塩精製晶析槽へ移送する。水の量は、残渣量の1.5倍程度とする。
無機塩精製晶析槽では、水を一定量留去したのち、槽内を冷却して無機塩を晶析させ、0.5〜1時間程度保持した後に遠心濾過装置へ移送し精製無機塩と廃水とに分離する。精製無機塩は無機塩溶解槽で再利用する。
前記晶析・共沈槽における無機物の結晶は貧溶媒の添加により添加した場所の極所的な溶解度変化により発生するため、結晶形状が粗く微孔を有し、この粗い組織に吸着された状態で金属イオンが共沈する。しかし、無機塩精製晶析槽では、液の濃縮及び冷却により槽全体が均一な状態に保持されるため、発生する結晶は強固で緻密となり、結晶表面に付着した母液を遠心濾過装置(G=1500以上)で精製することにより、金属イオンを含まない結晶を取り出すことが出来る。
The filter residue (coprecipitated metal-containing inorganic salt) is dissolved by supplying water (not shown) and transferred to an inorganic salt refining crystallization tank. The amount of water is about 1.5 times the amount of residue.
In the inorganic salt refining crystallization tank, after a certain amount of water is distilled off, the inside of the tank is cooled to crystallize the inorganic salt, and after holding for about 0.5 to 1 hour, it is transferred to a centrifugal filtration device and purified inorganic salt and Separated into wastewater. The purified inorganic salt is reused in the inorganic salt dissolution tank.
Inorganic crystals in the crystallization / coprecipitation tank are generated due to extreme changes in solubility at the place where the poor solvent is added, so the crystal shape is coarse and has micropores, and is adsorbed by this coarse structure. Metal ions co-precipitate. However, in the inorganic salt refining crystallization tank, since the entire tank is maintained in a uniform state by concentration and cooling of the liquid, the generated crystals become strong and dense, and the mother liquor adhering to the crystal surface is removed from the centrifugal filtration device (G = (1500 or more), a crystal containing no metal ions can be taken out.
図5は、本発明に係る精製リン酸を得る装置を金属エッチング装置のオンライン上に組み込んだ、金属エッチング液リサイクルシステムの他の例の概要を説明する図である。
図3に示したシステムとの大きな違いは、晶析・共沈槽の前に溶融晶析装置を設けたことであり、その他は図3の場合とほぼ同じである。
蒸発装置で分離した濃縮リン酸を溶融晶析装置に移送し、10℃前後に冷却してリン酸半水結晶を析出させた後、濾過装置(図示せず)で固液分離する。
分離したリン酸半水結晶は加熱溶解してエッチング液濃度調整装置に移送し、不足成分を補充した後、金属エッチング工程で再利用する。
濾液として排出される金属濃縮リン酸は、晶析・共沈槽に移送し、以下、図3の場合と同様に処理する。
但し、有機溶媒蒸発装置で貧溶媒を留去した精製リン酸に含まれる金属イオンの濃度が十分満足できないレベルである場合には、溶融晶析装置に戻して(図5中の点線で示した経路)再処理してもよい。
なお、図5には晶析・共沈槽の前に溶融晶析装置を設ける例を示したが、溶融晶析装置から排出されるリン酸半水結晶中の金属量は母液金属濃度に依存するため、濃縮リン酸の金属イオン濃度が極めて高い場合には、溶融晶析装置と晶析・共沈槽の順序を入れ替えるとよい。
FIG. 5 is a diagram for explaining the outline of another example of the metal etchant recycling system in which the apparatus for obtaining purified phosphoric acid according to the present invention is incorporated on-line of the metal etching apparatus.
A major difference from the system shown in FIG. 3 is that a melt crystallizer is provided in front of the crystallization / coprecipitation tank, and the other points are almost the same as those in FIG.
The concentrated phosphoric acid separated by the evaporator is transferred to a melt crystallizer, cooled to around 10 ° C. to precipitate a phosphoric acid hemihydrate crystal, and then solid-liquid separated by a filtration device (not shown).
The separated phosphoric acid hemihydrate crystal is heated and dissolved, transferred to an etching solution concentration adjusting device, supplemented with insufficient components, and then reused in a metal etching step.
The metal-enriched phosphoric acid discharged as a filtrate is transferred to a crystallization / coprecipitation tank and treated in the same manner as in FIG.
However, when the concentration of metal ions contained in the purified phosphoric acid obtained by distilling off the poor solvent with an organic solvent evaporator is at a level that is not sufficiently satisfactory, it is returned to the melt crystallizer (shown by the dotted line in FIG. 5). Path) may be reprocessed.
FIG. 5 shows an example in which a melt crystallizer is provided in front of the crystallization / coprecipitation tank. However, the amount of metal in the phosphoric acid hemihydrate discharged from the melt crystallizer depends on the concentration of the mother liquor metal. Therefore, when the metal ion concentration of concentrated phosphoric acid is extremely high, the order of the melt crystallization apparatus and the crystallization / coprecipitation tank may be changed.
本発明によれば、複数の金属イオンを含むリン酸水溶液から簡便に金属イオンを除去して精製リン酸を得る方法及び装置を提供でき、更には、金属エッチング工程で排出される高濃度のリン酸を含む混酸水溶液廃液に応用することにより、回収した精製リン酸を再利用するシステムを提供できる。
また、金属エッチング装置のオンライン上に本発明の精製リン酸を得る装置を組み込むことにより、混酸水溶液タンクの金属イオン濃度を常に一定以下に保持することが可能となり、エッチング工程が安定すると共に、混酸水溶液新液の補給量を大幅に減らす(従来の10重量%以下)ことができる。
According to the present invention, it is possible to provide a method and an apparatus for obtaining purified phosphoric acid by simply removing metal ions from a phosphoric acid aqueous solution containing a plurality of metal ions, and further, high concentration phosphorous discharged in the metal etching step. By applying it to a mixed acid aqueous solution waste containing acid, a system for reusing the recovered purified phosphoric acid can be provided.
In addition, by incorporating the apparatus for obtaining the purified phosphoric acid of the present invention on-line of the metal etching apparatus, it becomes possible to keep the metal ion concentration in the mixed acid aqueous solution tank always below a certain level, the etching process is stabilized and the mixed acid The replenishment amount of the new aqueous solution can be greatly reduced (10% by weight or less of the conventional solution).
以下、実施例を示して本発明を更に具体的に説明するが、本発明はこれらの実施例により限定されるものではない。   EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
実施例1
図3に示すリサイクルシステムを用いてAlエッチング工程の混酸水溶液廃液の処理を行った。なお、組成の単位は「kg」であり、「N.D.」は検出下限以下を表す。
エッチング工程から排出される混酸水溶液廃液(約100kg)の組成は次の通りであった。AlとMo以外の金属イオンは極めて少量のため無視した。
リン酸 硝酸 酢酸 水 Al Mo
65 10 3.5 21.5 0.030 0.045
また、蒸発装置からの留出液(約27.8kg)の組成は次の通りであった。
リン酸 硝酸 酢酸 水 Al Mo
N.D. 10 3.5 14.3 N.D. N.D.
また、蒸発装置を通った濃縮リン酸(約72.2kg)の組成は次の通りであった。
リン酸 硝酸 酢酸 水 Al Mo
65 N.D. N.D. 7.2 0.030 0.045
Example 1
The recycling system shown in FIG. 3 was used to treat the mixed acid aqueous solution waste liquid in the Al etching process. The unit of composition is “kg”, and “ND” represents the lower limit of detection.
The composition of the mixed acid aqueous solution waste liquid (about 100 kg) discharged from the etching process was as follows. Since metal ions other than Al and Mo were very small, they were ignored.
Phosphoric acid Nitric acid Acetic acid Water Al Mo
65 10 3.5 21.5 0.030 0.045
The composition of the distillate from the evaporator (about 27.8 kg) was as follows.
Phosphoric acid Nitric acid Acetic acid Water Al Mo
N. D. 10 3.5 14.3 N.P. D. N. D.
The composition of concentrated phosphoric acid (about 72.2 kg) that passed through the evaporator was as follows.
Phosphoric acid Nitric acid Acetic acid Water Al Mo
65 N.R. D. N. D. 7.2 0.030 0.045
次に、リン酸二水素ナトリウム7.4kgを水10kgに溶解し、晶析・共沈槽に加え、濃縮リン酸液と充分に混合した。充分攪拌した後、攪拌しながら無水IPAを260kg添加した。この段階での処理液(約349.6kg)の組成は次の通りであった。
なお、Naは無機物由来のものであり無機物に含まれるが、金属イオンについて説明する都合上、組成を記載した。後述する濾液、残渣、精製リン酸についても同様である。
リン酸 水 無機物 IPA Al Mo (Na)
65 17.2 7.4 260 0.030 0.045 1.43
また、濾過装置を通った濾液(約338.7kg)の組成は次の通りであった。
リン酸 水 無機物 IPA Al Mo (Na)
64 16.7 0.04 258 0.003 0.016 0.008
また、濾過装置の残渣(約10.9kg)の組成は次の通りであった。
リン酸 水 無機物 IPA Al Mo (Na)
1 0.5 7.36 2 0.027 0.029 1.422
上記濾液と残渣中のAl、Mo量を比較すると、Al、Moが残渣の方へ移行(共沈)しており、この操作で濃縮リン酸中のAl、Moが分離されていることが分かる。しかし添加した無機物によりNaイオンが付加されたため、これをできる限り除く必要があり、また、リン酸の純度を上げるため、濃縮リン酸中に溶解している無機物をできる限り除く必要がある。
Next, 7.4 kg of sodium dihydrogen phosphate was dissolved in 10 kg of water, added to the crystallization / coprecipitation tank, and thoroughly mixed with the concentrated phosphoric acid solution. After sufficiently stirring, 260 kg of anhydrous IPA was added while stirring. The composition of the treatment liquid (about 349.6 kg) at this stage was as follows.
In addition, although Na originates from an inorganic substance and is contained in an inorganic substance, the composition is described for convenience of explaining metal ions. The same applies to the filtrate, residue, and purified phosphoric acid described later.
Phosphoric acid Water Inorganic substance IPA Al Mo (Na)
65 17.2 7.4 260 0.030 0.045 1.43
The composition of the filtrate (about 338.7 kg) that passed through the filtration apparatus was as follows.
Phosphoric acid Water Inorganic substance IPA Al Mo (Na)
64 16.7 0.04 258 0.003 0.016 0.008
The composition of the filter residue (about 10.9 kg) was as follows.
Phosphoric acid Water Inorganic substance IPA Al Mo (Na)
1 0.5 7.36 2 0.027 0.029 1.422
When the amounts of Al and Mo in the filtrate and the residue are compared, it can be seen that Al and Mo are transferred (co-precipitated) toward the residue, and that Al and Mo in the concentrated phosphoric acid are separated by this operation. . However, since Na ions are added by the added inorganic substance, it is necessary to remove this as much as possible, and in order to increase the purity of phosphoric acid, it is necessary to remove as much as possible the inorganic substance dissolved in the concentrated phosphoric acid.
次に、濾液を有機溶媒蒸発装置に移送し、IPAと水を蒸発分離し、図示しないIPA回収用蒸留装置でIPAを回収し再利用した。更に、リン酸から完全にIPAを留去するため、IPA留去後のリン酸に水を加え、再蒸発させて共沸による脱溶媒を行った。有機溶媒蒸発装置の底から精製リン酸を得た。
得られた精製リン酸(約71.1kg)の組成は次の通りであった。
リン酸 水 無機物 IPA Al Mo (Na)
64 7.1 0.04 N.D. 0.003 0.016 0.008
上記精製リン酸は晶析・共沈操作を1回行ったものであるが、この組成で満足できない場合は、再度同様の操作を行い、金属イオンの除去を行えばよい。次にその例を示す。
1回目より母液の金属イオン濃度が低いため、無機物(リン酸二水素ナトリウム)の添加量を1/5量として行った。
得られた精製リン酸(約70.5kg)の組成は次の通りであり、更に純度の高い精製リン酸を得ることができた。
リン酸 水 無機物 IPA Al Mo
63.5 7.0 0.02 N.D. 0.00004 0.00061
(Na)
0.004
Next, the filtrate was transferred to an organic solvent evaporation apparatus, IPA and water were evaporated and separated, and IPA was recovered and reused by an IPA recovery distillation apparatus (not shown). Furthermore, in order to completely distill off IPA from phosphoric acid, water was added to the phosphoric acid after distilling off IPA, and it was re-evaporated to remove the solvent by azeotropic distillation. Purified phosphoric acid was obtained from the bottom of the organic solvent evaporator.
The composition of the obtained purified phosphoric acid (about 71.1 kg) was as follows.
Phosphoric acid Water Inorganic substance IPA Al Mo (Na)
64 7.1 0.04 N.P. D. 0.003 0.016 0.008
The purified phosphoric acid is obtained by performing the crystallization / coprecipitation operation once. However, if this composition is not satisfactory, the same operation may be performed again to remove metal ions. An example is shown below.
Since the metal ion concentration of the mother liquor was lower than the first time, the amount of inorganic substance (sodium dihydrogen phosphate) added was set to 1/5.
The composition of the obtained purified phosphoric acid (about 70.5 kg) was as follows, and purified phosphoric acid with higher purity could be obtained.
Phosphoric acid Water Inorganic substance IPA Al Mo
63.5 7.0 0.02 N.E. D. 0.00004 0.00061
(Na)
0.004
前記残渣(約10.9kg)を無機塩精製晶析槽に移送して処理した精製無機塩(約7.5kg)の結晶の組成は次の通りであり、無機物溶解槽で再利用したが問題は無かった。
リン酸 水 無機物 IPA Al Mo (Na)
N.D. 0.5 7.0 N.D. N.D. N.D. 1.34
以上のように、本発明のシステムによれば、混酸水溶液廃液中のリン酸の約98重量%を再利用することができ、混酸水溶液新液の投入量を大幅に削減することが可能である。
The composition of the crystal of purified inorganic salt (about 7.5 kg) obtained by transferring the residue (about 10.9 kg) to the inorganic salt refining crystallization tank is as follows. There was no.
Phosphoric acid Water Inorganic substance IPA Al Mo (Na)
N. D. 0.5 7.0 N.I. D. N. D. N. D. 1.34
As described above, according to the system of the present invention, about 98% by weight of phosphoric acid in the mixed acid aqueous solution waste liquid can be reused, and the input amount of the new mixed acid aqueous solution can be greatly reduced. .
実施例2
実施例1と同じAlエッチング工程の混酸水溶液廃液の処理を行った。
エッチング工程から排出される混酸水溶液廃液(約100kg)の組成、蒸発装置からの留出液(約27.8kg)の組成、蒸発装置を通った濃縮リン酸(約72.2kg)の組成は実施例1と同じである。
次に、無機塩を硫酸ナトリウム4.43kgに変え、水18kgに溶解して用いた点以外は実施例1と同様の操作を行った。この段階での処理液(約354.6kg)の組成は次の通りであった。
なお、Na量と無機物量の関係については、実施例1と同様である。
リン酸 水 無機物 IPA Al Mo (Na)
65 25.2 4.43 260 0.030 0.045 1.43
また、濾過装置を通った濾液(約346.5kg)の組成は次の通りであった。
リン酸 水 無機物 IPA Al Mo (Na)
64 24.5 0.02 258 0.002 0.010 0.006
また、濾過装置の残渣(約8.1kg)の組成は次の通りであった。
リン酸 水 無機物 IPA Al Mo (Na)
1 0.7 4.41 2 0.028 0.035 1.424
上記濾液と残渣中のAl、Mo量を比較すると、Al、Moが残渣の方へ移行(共沈)しており、この操作で濃縮リン酸中のAl、Moが分離されていることが分かる。しかし添加した無機物によりNaイオンとSO 2−イオンが付加されたため、これをできる限り除く必要があり、また、リン酸の純度を上げるため、濃縮リン酸中に溶解している無機物をできる限り除く必要がある。
次に、濾液を有機溶媒蒸発装置に供給し、実施例1と同様の操作を行った結果、得られた精製リン酸(約71.1kg)の組成は次の通りであった。SO 2−イオンについては、除去されずに僅かに残ったNa(0.006kg)と硫酸ナトリウム塩を形成する分が残存している。
リン酸 水 無機物 IPA Al Mo (Na)
64 7.1 0.02 N.D. 0.002 0.010 0.006
Example 2
The mixed acid aqueous solution waste liquid of the same Al etching process as Example 1 was processed.
The composition of the mixed acid aqueous solution waste solution (about 100 kg) discharged from the etching process, the composition of the distillate from the evaporator (about 27.8 kg), and the composition of concentrated phosphoric acid (about 72.2 kg) that passed through the evaporator were implemented. Same as Example 1.
Next, the same operation as in Example 1 was performed except that the inorganic salt was changed to 4.43 kg of sodium sulfate and dissolved in 18 kg of water. The composition of the treatment liquid (about 354.6 kg) at this stage was as follows.
The relationship between the amount of Na and the amount of inorganic material is the same as in Example 1.
Phosphoric acid Water Inorganic substance IPA Al Mo (Na)
65 25.2 4.43 260 0.030 0.045 1.43
The composition of the filtrate (about 346.5 kg) that passed through the filtration device was as follows.
Phosphoric acid Water Inorganic substance IPA Al Mo (Na)
64 24.5 0.02 258 0.002 0.010 0.006
The composition of the filter residue (about 8.1 kg) was as follows.
Phosphoric acid Water Inorganic substance IPA Al Mo (Na)
1 0.7 4.41 2 0.028 0.035 1.424
When the amounts of Al and Mo in the filtrate and the residue are compared, it can be seen that Al and Mo are transferred (co-precipitated) toward the residue, and that Al and Mo in the concentrated phosphoric acid are separated by this operation. . However, since Na ions and SO 4 2− ions were added by the added inorganic substances, it is necessary to remove them as much as possible. In order to increase the purity of phosphoric acid, the inorganic substances dissolved in the concentrated phosphoric acid should be removed as much as possible. It is necessary to remove.
Next, the filtrate was supplied to an organic solvent evaporator, and the same operation as in Example 1 was performed. As a result, the composition of the obtained purified phosphoric acid (about 71.1 kg) was as follows. For SO 4 2-ions, minutes to form a slightly remaining Na (0.006 kg) and sodium sulfate not removed is left.
Phosphoric acid Water Inorganic substance IPA Al Mo (Na)
64 7.1 0.02 N.R. D. 0.002 0.010 0.006
実施例3
図3に示すリサイクルシステムを用いて、実施例1と同様にしてAlエッチング工程の混酸水溶液廃液の処理を行った。図4は基本ブロック毎の物質収支を示したものである。
本実施例において、混酸水溶液タンクの金属イオン濃度(Al、Mo、Naの総量)を重量基準で500ppm以下に保持するためには、混酸水溶液廃液の処理量を100kg/h、リサイクル混酸水溶液を90kg/hとし、リサイクル混酸水溶液の金属イオン濃度を重量基準で30ppm以下に抑え、混酸水溶液新液(補充用)を10kg/h補充するとした場合、エッチング金属量の上限は、次式のように、0.0473kg/hとなる。
100kg/h×0.0005−100kg/h×0.9×0.00003
=0.0473kg/h
Example 3
Using the recycling system shown in FIG. 3, the mixed acid aqueous solution waste liquid in the Al etching process was treated in the same manner as in Example 1. FIG. 4 shows the material balance for each basic block.
In this example, in order to maintain the metal ion concentration (total amount of Al, Mo, Na) in the mixed acid aqueous solution tank at 500 ppm or less on the weight basis, the treatment amount of the mixed acid aqueous solution waste liquid is 100 kg / h, and the recycled mixed acid aqueous solution is 90 kg. / H, the metal ion concentration of the recycled mixed acid aqueous solution is suppressed to 30 ppm or less on a weight basis, and the new mixed acid aqueous solution (for replenishment) is replenished at 10 kg / h, the upper limit of the etching metal amount is as follows: 0.0473 kg / h.
100kg / h × 0.0005-100kg / h × 0.9 × 0.00003
= 0.0473kg / h
実施例4
図5に示すリサイクルシステムを用いてAlエッチング工程の混酸水溶液廃液の処理を行った。エッチング工程から排出される混酸水溶液廃液(約100kg)の組成、蒸発装置からの留出液(約27.8kg)の組成、蒸発装置を通った濃縮リン酸(約72.2kg)の組成は実施例1と同じである。
次に、濃縮リン酸を溶融晶析装置に移送し、約10℃に冷却してリン酸半水結晶を晶析させた。次いで、濾過装置でリン酸半水結晶を固液分離した後、加熱溶解してエッチング液濃度調整装置に移送し、不足成分を補充して金属エッチング工程で再利用した。得られたリン酸半水結晶の組成は次の通りである。
リン酸 水 Al Mo
52 4.8 0.001 0.0015
また、濾液の組成は次の通りである。
リン酸 水 Al Mo
13 2.4 0.029 0.0435
上記濾液を晶析・共沈槽に移送し、実施例1と同様な処理を行った結果、得られた精製リン酸(13.8kg)の組成は次の通りであった。
リン酸 水 無機物 IPA Al Mo
12.4 1.4 0.01 N.D. 0.0008 0.0035
(Na)
0.002
上記精製リン酸を溶融晶析工程へ戻して、再度上記と同様の処理を行ったところ、次のような組成の精製リン酸が得られた。
リン酸 水 無機物 IPA Al Mo
9.9 0.9 0.0003 N.D. 0.00003 0.0001
(Na)
0.00007
上記のように溶融晶析を繰り返せば、純度の高い精製リン酸が得られることが分かる。
Example 4
The recycling system shown in FIG. 5 was used to treat the mixed acid aqueous solution waste liquid in the Al etching process. The composition of the mixed acid aqueous solution waste solution (about 100 kg) discharged from the etching process, the composition of the distillate from the evaporator (about 27.8 kg), and the composition of concentrated phosphoric acid (about 72.2 kg) that passed through the evaporator were implemented. Same as Example 1.
Next, the concentrated phosphoric acid was transferred to a melt crystallizer and cooled to about 10 ° C. to crystallize the phosphoric acid hemihydrate crystal. Next, the phosphoric acid hemihydrate crystal was solid-liquid separated by a filtration device, heated and dissolved, transferred to an etching solution concentration adjusting device, supplemented with insufficient components, and reused in the metal etching step. The composition of the obtained phosphoric acid half-water crystal is as follows.
Phosphoric acid water Al Mo
52 4.8 0.001 0.0015
The composition of the filtrate is as follows.
Phosphoric acid water Al Mo
13 2.4 0.029 0.0435
The filtrate was transferred to a crystallization / coprecipitation tank and subjected to the same treatment as in Example 1. As a result, the composition of the obtained purified phosphoric acid (13.8 kg) was as follows.
Phosphoric acid Water Inorganic substance IPA Al Mo
12.4 1.4 0.01 N.I. D. 0.0008 0.0035
(Na)
0.002
When the purified phosphoric acid was returned to the melt crystallization step and the same treatment as described above was performed again, purified phosphoric acid having the following composition was obtained.
Phosphoric acid Water Inorganic substance IPA Al Mo
9.9 0.9 0.0003 N. D. 0.00003 0.0001
(Na)
0.00007
It can be seen that purified phosphoric acid with high purity can be obtained by repeating melt crystallization as described above.
実施例5
図5に示すリサイクルシステムを用いて、実施例1と同様にしてAlエッチング工程の混酸水溶液廃液の処理を行った。図6は基本ブロック毎の物質収支を示したものである。
本実施例において、混酸水溶液タンクの金属イオン濃度(Al、Mo、Naの総量)を重量基準で500ppm以下に保持するためには、混酸水溶液廃液の処理量を100kg/h、リサイクル混酸水溶液を98kg/hとし、リサイクル混酸水溶液の金属イオン濃度を重量基準で30ppm以下に抑え、混酸水溶液新液(補充用)を2kg/h補充するとした場合、エッチング金属量の上限は、次式のように、0.04706kg/hとなる。
100kg/h×0.0005−100kg/h×0.98×0.00003
=0.04706kg/h
Example 5
The recycling system shown in FIG. 5 was used to treat the mixed acid aqueous solution waste liquid in the Al etching step in the same manner as in Example 1. FIG. 6 shows the material balance for each basic block.
In this example, in order to maintain the metal ion concentration (total amount of Al, Mo, Na) in the mixed acid aqueous solution tank at 500 ppm or less on the weight basis, the treatment amount of the mixed acid aqueous solution waste liquid is 100 kg / h, and the recycled mixed acid aqueous solution is 98 kg. / H, when the metal ion concentration of the recycled mixed acid aqueous solution is suppressed to 30 ppm or less on a weight basis, and 2 kg / h of the mixed acid aqueous solution new solution (for replenishment) is replenished, the upper limit of the etching metal amount is as follows: 0.04706 kg / h.
100kg / h × 0.0005-100kg / h × 0.98 × 0.00003
= 0.04706 kg / h
金属エッチング工程の装置の概要を示す図。The figure which shows the outline | summary of the apparatus of a metal etching process. 混酸水溶液精製装置の一部である蒸発装置の概要を示す図。The figure which shows the outline | summary of the evaporation apparatus which is a part of mixed acid aqueous solution refinement | purification apparatus. 金属エッチング液リサイクルシステムの一例の概要を説明する図。The figure explaining the outline | summary of an example of a metal etching liquid recycling system. 実施例3における基本ブロック毎の物質収支を示す図。The figure which shows the material balance for every basic block in Example 3. FIG. 金属エッチング液リサイクルシステムの他の例の概要を説明する図。The figure explaining the outline | summary of the other example of a metal etching liquid recycling system. 実施例5における基本ブロック毎の物質収支を示す図。The figure which shows the material balance for every basic block in Example 5. FIG.

Claims (8)

  1. 〔1〕複数の金属イオンを含むリン酸水溶液に無機塩水溶液を混合し、次いでリン酸に可溶でかつ無機塩を溶解しない有機溶媒(以下、貧溶媒という)を加えて混合することにより無機塩の結晶を析出させると同時に、前記金属イオンを共沈させた後、該金属イオンを含む無機塩の結晶を濾過して固液分離する工程、
    〔2〕濾過した濾液中の貧溶媒及び水を蒸発させる工程、
    を含むことを特徴とする精製リン酸を得る方法。
    [1] An inorganic salt aqueous solution is mixed with a phosphoric acid aqueous solution containing a plurality of metal ions, and then an inorganic solvent that is soluble in phosphoric acid and does not dissolve the inorganic salt (hereinafter referred to as a poor solvent) is added and mixed. A step of co-precipitating the metal ions at the same time as the salt crystals are precipitated, and then filtering the inorganic salt crystals containing the metal ions for solid-liquid separation;
    [2] a step of evaporating the poor solvent and water in the filtered filtrate;
    A method for obtaining purified phosphoric acid comprising
  2. 〔1〕〔2〕の工程を複数回繰り返すことを特徴とする請求項1記載の精製リン酸を得る方法。   The method of obtaining purified phosphoric acid according to claim 1, wherein the steps [1] and [2] are repeated a plurality of times.
  3. 複数の金属イオンを含むリン酸水溶液が、重量基準で500ppm〜金属イオンとしてリン酸水溶液に溶解する上限までの金属イオンを含むことを特徴とする請求項1又は2記載の精製リン酸を得る方法。 Phosphoric acid aqueous solution containing a plurality of metal ions, purification phosphate according to claim 1 or 2, wherein the containing metal ions in the upper or dissolved in phosphoric acid aqueous solution as 500ppm~ metal ions in heavy basis How to get.
  4. 金属イオンを共沈させ濾過した無機塩の結晶を温水で溶解し、次いで、無機塩の結晶を析出させ、共沈していた金属を無機塩から分離した後、濾過して無機塩を回収し再利用することを特徴とする請求項1〜3の何れかに記載の精製リン酸を得る方法。   The inorganic salt crystals that have been co-precipitated and filtered are dissolved in warm water, and then the inorganic salt crystals are precipitated. After the coprecipitated metal is separated from the inorganic salt, the inorganic salt is recovered by filtration. The method for obtaining purified phosphoric acid according to any one of claims 1 to 3, wherein the phosphoric acid is reused.
  5. 少なくとも、無機塩を溶解する機能を有する無機塩溶解槽、複数の金属イオンを含むリン酸水溶液と貧溶媒と無機塩水溶液を混合するための攪拌機を具備した晶析・共沈槽、無機塩結晶の濾過装置、及び、濾液から貧溶媒と水を蒸発させるための加熱設備を具備した有機溶媒蒸発装置を有することを特徴とする請求項1〜3の何れかに記載の方法を実施するための装置。   At least an inorganic salt dissolution tank having a function of dissolving an inorganic salt, a crystallization / coprecipitation tank equipped with a stirrer for mixing a phosphoric acid aqueous solution containing a plurality of metal ions, a poor solvent and an inorganic salt aqueous solution, an inorganic salt crystal The organic solvent evaporation apparatus provided with the heating equipment for evaporating a poor solvent and water from a filtration apparatus and a filtrate is used for implementing the method in any one of Claims 1-3 characterized by the above-mentioned. apparatus.
  6. 濾過した無機塩の結晶を温水で溶解し再度結晶を析出させるための無機塩精製晶析槽、及び、析出させた無機塩の結晶を分離するための濾過装置を有することを特徴とする請求項5記載の装置。   An inorganic salt refining crystallization tank for dissolving a filtered inorganic salt crystal with warm water and precipitating the crystal again, and a filtration device for separating the precipitated inorganic salt crystal. 5. The apparatus according to 5.
  7. 金属エッチング装置、エッチング後液を貯留する混酸水溶液タンク、混酸水溶液廃液タンク、混酸水溶液廃液から硝酸・酢酸・水を蒸発させて留去する装置(蒸発装置)、及び、請求項5又は6記載の装置を有し、混酸水溶液を再利用するように設計されていることを特徴とする金属のエッチングシステム。   The metal etching apparatus, the mixed acid aqueous solution tank for storing the liquid after etching, the mixed acid aqueous solution waste tank, the apparatus for evaporating and distilling nitric acid / acetic acid / water from the mixed acid aqueous solution waste liquid (evaporation apparatus), and claim 5 or 6 Metal etching system characterized in that it has an apparatus and is designed to reuse mixed acid aqueous solution.
  8. 更に、前記蒸発装置で硝酸・酢酸・水を留去した後の濃縮リン酸の溶融晶析装置を有することを特徴とする請求項7記載の金属のエッチングシステム。   The metal etching system according to claim 7, further comprising a melt crystallizer for concentrated phosphoric acid after the nitric acid, acetic acid, and water are distilled off by the evaporator.
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JP4766858B2 (en) * 2004-09-02 2011-09-07 日本リファイン株式会社 Method and apparatus for recovering phosphoric acid from metal-containing mixed acid aqueous solution containing phosphoric acid and at least one acid other than phosphoric acid
JP2006315931A (en) * 2005-05-16 2006-11-24 Nippon Refine Kk Method and apparatus for recovering phosphoric acid from metal ion-containing mixed acid aqueous solution containing phosphoric acid and at least one kind of acid except phosphoric acid
JP4873894B2 (en) 2005-06-27 2012-02-08 下関三井化学株式会社 Method for producing high purity purified phosphoric acid
KR100655429B1 (en) * 2005-11-10 2006-12-08 삼성전자주식회사 System and method for regenerating the phosphoric acid solution, and apparatus for treating substrate with the system

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