JP2008272687A - Method for reducing amount of waste liquid and method for treating waste liquid - Google Patents

Method for reducing amount of waste liquid and method for treating waste liquid Download PDF

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JP2008272687A
JP2008272687A JP2007120387A JP2007120387A JP2008272687A JP 2008272687 A JP2008272687 A JP 2008272687A JP 2007120387 A JP2007120387 A JP 2007120387A JP 2007120387 A JP2007120387 A JP 2007120387A JP 2008272687 A JP2008272687 A JP 2008272687A
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waste liquid
inorganic salt
liquid
sodium sulfate
amount
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JP4588045B2 (en
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Hiroyuki Ito
博之 伊藤
Sadaki Yoshino
節己 吉野
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SANBO CHEMICAL INDUSTRY Inc
Daiseki Co Ltd
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SANBO CHEMICAL INDUSTRY Inc
Daiseki Co Ltd
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00Technologies relating to the processing of minerals
    • Y02P40/10Production of cement, e.g. improving or optimising the production methods; Cement grinding

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  • Treatment Of Sludge (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for reducing the amount of a waste liquid by concentrating a waste liquid and subjecting the concentrate to solid liquid separation to give a waste liquid of which the inorganic salt content has been lowered, and to provide a method for treating a waste liquid by subjecting a specific component contained in a recovered inorganic salt and the like to purification and the like for reutilization of the purified component. <P>SOLUTION: The method for reducing the amount of a waste liquid is characterized by concentrating a waste liquid containing an inorganic salt (for example, sodium sulfate) to give a concentrated waste liquid and separating the concentrated waste liquid into a solid component and a liquid component (for example, by centrifugation). The method for treating a waste liquid is characterized by comprising the amount reduction step in the method for reducing the amount of a waste liquid. For example, a method may be adopted in which a calcium compound is added to a liquid component containing sulfate ions to give sludge, and the sludge is dehydrated to give a dehydrate which is then reutilized as a material for cement. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は廃液の減量方法及び廃液の処理方法に関する。更に詳しくは、廃液を濃縮し、含有される無機塩の一部を晶析させ、次いで、固液分離して、無機塩が含有される固形状分を除去し、処理すべき廃液を減量させる廃液の減量方法、及びこの減量方法における減量工程を備える廃液の処理方法に関する。   The present invention relates to a waste liquid reduction method and a waste liquid treatment method. More specifically, the waste liquid is concentrated, a part of the contained inorganic salt is crystallized, and then solid-liquid separation is performed to remove the solid component containing the inorganic salt, thereby reducing the waste liquid to be treated. The present invention relates to a waste liquid reduction method and a waste liquid treatment method including a weight reduction step in the weight reduction method.

工場等で発生する廃液は、処理場まで、車両により運搬するにしても、パイプライン等により搬送するにしてもコストがかかり、更に処理費用も処理量に応じて発生するため可能な限り減量することが好ましい。この処理すべき廃液を減量するため、従来、廃液の濃縮がなされているが(例えば、特許文献1参照。)、濃縮は無機塩が析出するまでが限度であり、必ずしも十分に処理すべき廃液を減量することはできなかった。また、無機塩が析出するまで濃縮した場合、有用な無機塩を回収し、再利用するときに、この無機塩により多くの有害物及び不純物等が混入し、商品価値の高い再利用品とすることができなかった。更に、従来、回収し、再利用する価値のある無機塩である場合、この無機塩を効率よく回収するため、回収に適した特定の廃液が用いられるのが一般的であり、廃液の種類によらず効率よく、高い品質で有用な無機塩を回収し、且つ処理すべき廃液の総量を減量させることができる技術が必要とされている。   Waste liquid generated in factories, etc. is costly whether it is transported to a treatment plant by a vehicle or transported by a pipeline, etc. Further, since the processing costs are generated according to the processing amount, the amount is reduced as much as possible. It is preferable. In order to reduce the amount of waste liquid to be treated, the waste liquid has been conventionally concentrated (for example, see Patent Document 1). However, the concentration is limited until the inorganic salt is precipitated, and the waste liquid to be sufficiently treated is not necessarily used. Could not lose weight. In addition, when the inorganic salt is concentrated until it precipitates, when the useful inorganic salt is recovered and reused, many harmful substances and impurities are mixed into the inorganic salt, resulting in a reusable product with high commercial value. I couldn't. Furthermore, conventionally, when an inorganic salt is worth recovering and reusing, in order to efficiently recover this inorganic salt, a specific waste liquid suitable for recovery is generally used. Regardless, there is a need for a technique that can efficiently recover high-quality and useful inorganic salts and reduce the total amount of waste liquid to be treated.

特開平9−327688号公報JP-A-9-327688

本発明は、上記の従来の状況に鑑みてなされたものであり、廃液を濃縮し、含有される無機塩の一部を晶析させ、固液分離して、無機塩が含有される固形状分を除去し、処理を必要とする廃液を減量させる廃液の減量方法、及び回収された無機塩及び/又は無機塩の含有量が減少した廃液に含有される無機塩のうち商品価値のある特定の成分を精製し、又は加工し、製品として再利用する廃液の処理方法を提供することを目的とする。   The present invention has been made in view of the above-described conventional situation, and concentrates the waste liquid, crystallizes a part of the contained inorganic salt, solid-liquid separates, and solids containing the inorganic salt A method for reducing the amount of waste liquid that removes waste and reduces the amount of waste liquid that needs to be treated, and identification of the inorganic salt contained in the recovered waste liquid and / or inorganic salt that has a reduced content of inorganic salt that has commercial value It aims at providing the processing method of the waste liquid which refine | purifies or processes the component of this and reuses it as a product.

本発明は以下のとおりである。
1.無機塩を含有する廃液を濃縮して濃縮廃液とし、該濃縮廃液から該無機塩の一部を晶析させ、次いで、固形状分と液状分とに分離することを特徴とする廃液の減量方法。
2.上記液状分を再濃縮する上記1.に記載の廃液の減量方法。
3.上記無機塩を100質量%とした場合に、上記固形状分に含有される該無機塩は60〜90質量%である上記1.又は2.に記載の廃液の減量方法。
4.上記無機塩が、硫酸ナトリウム、塩化ナトリウム、亜硫酸ナトリウム及び亜硝酸ナトリウムのうちの少なくとも1種である上記1.乃至3.のうちのいずれか1項に記載の廃液の減量方法。
5.上記無機塩が硫酸ナトリウムであり、該硫酸ナトリウムが、硫酸を含有する廃液を水酸化ナトリウムにより中和した廃液、又は水酸化ナトリウムを含有する廃液を硫酸により中和した廃液に含有されるものである上記1.乃至4.うちのいずれか1項に記載の廃液の減量方法。
6.上記固形状分に含有される上記無機塩を精製し、及び/又は加工し、再利用する上記1.乃至5.のうちのいずれか1項に記載の廃液の減量方法。
7.上記無機塩が硫酸ナトリウムであり、上記濃縮廃液から硫酸ナトリウム十水和物を晶析させ、その後、該硫酸ナトリウム十水和物を用いて硫酸ナトリウム無水物を生成させる上記6.に記載の廃液の処理方法。
8.無機塩を含有する廃液の処理方法であって、上記1.乃至7.のうちのいずれか1項に記載の廃液の減量方法における減量工程を備えることを特徴とする廃液の処理方法。
9.上記液状分が硫酸イオンを含有し、該液状分にカルシウム化合物を添加して汚泥を生成させ、その後、該汚泥を脱水して脱水物とし、該脱水物をセメント原料として用いる上記8.に記載の廃液の処理方法。
10.上記液状分が硫酸イオンを含有し、該液状分を上記減量工程がなされる場所から他場所に運搬し、その後、該液状分にカルシウム化合物を添加して汚泥を生成させ、次いで、該汚泥を脱水して脱水物とし、該脱水物をセメント原料として用いる上記8.に記載の廃液の処理方法。
The present invention is as follows.
1. A waste liquid reducing method comprising concentrating a waste liquid containing an inorganic salt to obtain a concentrated waste liquid, crystallizing a part of the inorganic salt from the concentrated waste liquid, and then separating it into a solid part and a liquid part .
2. 1. Reconcentrate the liquid component. The method for reducing the amount of waste liquid described in 1.
3. When the inorganic salt is 100% by mass, the inorganic salt contained in the solid content is 60 to 90% by mass. Or 2. The method for reducing the amount of waste liquid described in 1.
4). The above 1. wherein the inorganic salt is at least one of sodium sulfate, sodium chloride, sodium sulfite and sodium nitrite. To 3. The method for reducing the amount of waste liquid according to any one of the above.
5. The inorganic salt is sodium sulfate, and the sodium sulfate is contained in a waste liquid obtained by neutralizing a waste liquid containing sulfuric acid with sodium hydroxide or a waste liquid obtained by neutralizing a waste liquid containing sodium hydroxide with sulfuric acid. Certain above 1. To 4. The method for reducing the amount of waste liquid according to any one of the above.
6). 1. The inorganic salt contained in the solid content is purified and / or processed and reused. To 5. The method for reducing the amount of waste liquid according to any one of the above.
7). 6. The inorganic salt is sodium sulfate, and sodium sulfate decahydrate is crystallized from the concentrated waste liquid, and then sodium sulfate decahydrate is produced using the sodium sulfate decahydrate. A method for treating a waste liquid according to 1.
8). A method for treating a waste liquid containing an inorganic salt, comprising: To 7. A waste liquid treatment method comprising a weight reduction step in the waste liquid reduction method according to claim 1.
9. The liquid component contains sulfate ions, and a calcium compound is added to the liquid component to generate sludge. Thereafter, the sludge is dehydrated to obtain a dehydrated product, and the dehydrated product is used as a cement raw material. A method for treating a waste liquid according to 1.
10. The liquid content contains sulfate ions, and the liquid content is transported from the place where the weight reduction process is performed to another place, and then a calcium compound is added to the liquid content to generate sludge. 8. Dehydration to obtain a dehydrated product, which is used as a cement raw material. A method for treating a waste liquid according to 1.

本発明の廃液の減量方法によれば、濃縮廃液から無機塩の一部を晶析させ、その後、固形状分と液状分とが分離されるため、処理を必要とする廃液を効率よく減量させることができる。また、処理すべき廃液が十分に減量されるため、専用の車両等により運送するとき、又は配管等により移送するときの搬送費を低減させることができる。更に、固形状分及び/又は液状分から有用な無機塩等を回収する場合、全量を固形分として回収するときと比べて高品質の商品価値の高い再利用品とすることができる。また、高濃度の無機塩を含有する廃液を河川等に放流することは環境保全上望ましくなく、更に、活性汚泥処理等の生物処理においても、高濃度の無機塩を含有する廃液は処理を困難にする要因となり、無機塩の濃度には自ずと上限があるが、本願発明では、廃液における無機塩の含有量が十分に低減されて廃液の処理が容易となり、且つ処理すべき廃液量も低減され、廃液処理が容易となる。このように、本願発明の廃液の減量方法は極めて有用な技術である。
また、液状分を再濃縮する場合は、特に、上記と同様の操作とすることにより、処理すべき廃液をより減量させることができる。
更に、無機塩を100質量%とした場合に、固形状分に含有される無機塩が60〜90質量%である場合は、廃液の減量が効率よくなされ、処理すべき廃液を十分に減量させることができ、且つ有用な無機塩を回収し、再利用する場合、有害物及び不純物等の混入が少ない品質の高い再利用品とすることができる。
また、無機塩が、硫酸ナトリウム、塩化ナトリウム、亜硫酸ナトリウム及び亜硝酸ナトリウムのうちの少なくとも1種である場合は、廃液の中和等により多量に生成するこれらの無機塩を含有する廃液を効率よく減量させることができる。
更に、無機塩が硫酸ナトリウムであり、硫酸ナトリウムが、硫酸を含有する廃液を水酸化ナトリウムにより中和した廃液、又は水酸化ナトリウムを含有する廃液を硫酸により中和した廃液に含有されるものである場合は、酸洗、脱硫等により多量に発生するこれらの廃液を効率よく減量させることができる。
また、固形状分に含有される無機塩を精製し、及び/又は加工し、再利用する場合は、有害物等の多くが液状分に含有されているため、より純度及び商品価値の高い再利用品とすることができる。
更に、無機塩が硫酸ナトリウムであり、濃縮廃液から硫酸ナトリウム十水和物を晶析させ、その後、硫酸ナトリウム十水和物を用いて硫酸ナトリウム無水物を生成させる場合は、廃液の種類を特定することなく、硫酸ナトリウム十水和物及び無水物を同一の廃液から容易に回収することができ、且つ高品質で商品価値の高い十水和物又は無水物として回収することができる。
本発明の廃液の処理方法によれば、本発明の廃液の減量方法における減量工程を備えるため、廃液を効率よく処理することができ、特に有害物及び不純物等の混入が少ない品質の高い再利用品を回収することができる。
また、液状分が硫酸イオンを含有し、この液状分にカルシウム化合物を添加して汚泥を生成させ、その後、汚泥を脱水して脱水物とし、脱水物をセメント原料として用いる場合は、廃液に含有される無機塩を容易に減量させることができるとともに、回収したものをセメント原料として有効に活用することができる。このように、廃液に含有される成分のうちの無用な不純物等を除くほとんど全ての成分を回収し、有効に再利用することができる。
更に、液状分が硫酸イオンを含有し、この液状分を減量工程がなされる場所から他場所に運搬し、その後、液状分にカルシウム化合物を添加して汚泥を生成させ、その後、汚泥を脱水して脱水物とし、脱水物をセメント原料として用いる場合は、廃液が十分に減量されているため、運搬コストを低減させることができ、無機塩をセメント原料として回収することと併せて廃液処理のコストを大きく削減させることができる。
According to the method for reducing the amount of waste liquid of the present invention, a part of the inorganic salt is crystallized from the concentrated waste liquid, and then the solid part and the liquid part are separated, so that the waste liquid that requires treatment can be efficiently reduced. be able to. In addition, since the amount of waste liquid to be processed is sufficiently reduced, it is possible to reduce the transportation cost when transported by a dedicated vehicle or the like or transported by piping or the like. Furthermore, when recovering useful inorganic salts and the like from the solid and / or liquid components, it is possible to obtain a recycled product with high quality and high commercial value as compared with the case where the entire amount is recovered as a solid component. In addition, it is not desirable for environmental conservation to discharge waste liquid containing high concentration inorganic salt to rivers, etc. Further, in biological treatment such as activated sludge treatment, waste liquid containing high concentration inorganic salt is difficult to treat. However, in the present invention, the content of the inorganic salt in the waste liquid is sufficiently reduced to facilitate the treatment of the waste liquid, and the amount of the waste liquid to be treated is also reduced. , Waste liquid treatment becomes easy. Thus, the method for reducing the amount of waste liquid according to the present invention is an extremely useful technique.
Moreover, when reconcentrating a liquid content, the waste liquid which should be processed can be reduced more by carrying out operation similar to the above especially.
Furthermore, when the inorganic salt is 100% by mass and the inorganic salt contained in the solid content is 60 to 90% by mass, the waste liquid is efficiently reduced, and the waste liquid to be treated is sufficiently reduced. In the case where the useful inorganic salt can be recovered and reused, it is possible to obtain a high-quality reuse product with less contamination of harmful substances and impurities.
In addition, when the inorganic salt is at least one of sodium sulfate, sodium chloride, sodium sulfite and sodium nitrite, the waste liquid containing these inorganic salts produced in large quantities by neutralization of the waste liquid can be efficiently used. Can be reduced.
Further, the inorganic salt is sodium sulfate, and the sodium sulfate is contained in a waste liquid obtained by neutralizing a waste liquid containing sulfuric acid with sodium hydroxide or a waste liquid obtained by neutralizing a waste liquid containing sodium hydroxide with sulfuric acid. In some cases, these waste liquids generated in large quantities by pickling, desulfurization, etc. can be efficiently reduced.
In addition, when the inorganic salt contained in the solid content is purified and / or processed and reused, many of harmful substances are contained in the liquid content. It can be used.
Furthermore, when the inorganic salt is sodium sulfate and sodium sulfate decahydrate is crystallized from the concentrated waste liquid and then sodium sulfate decahydrate is produced using sodium sulfate decahydrate, the type of waste liquid is specified. Therefore, sodium sulfate decahydrate and anhydride can be easily recovered from the same waste liquid, and can be recovered as decahydrate or anhydride having high quality and high commercial value.
According to the waste liquid treatment method of the present invention, since the waste liquid reduction method of the present invention includes a weight reduction step, the waste liquid can be efficiently processed, and in particular, high quality reuse with less contamination of harmful substances and impurities. Goods can be collected.
In addition, if the liquid component contains sulfate ions, a calcium compound is added to this liquid component to produce sludge, and then the sludge is dehydrated to give a dehydrated product. It is possible to easily reduce the amount of the inorganic salt to be collected and to effectively use the recovered material as a cement raw material. Thus, almost all components except unnecessary impurities among the components contained in the waste liquid can be recovered and reused effectively.
Furthermore, the liquid component contains sulfate ions, and this liquid component is transported from the place where the weight reduction process is performed to another place, and then a calcium compound is added to the liquid component to generate sludge, and then the sludge is dehydrated. When the dehydrated product is used as a cement raw material, the waste liquid is sufficiently reduced, so the transportation cost can be reduced, and the waste liquid treatment cost is combined with the recovery of the inorganic salt as the cement raw material. Can be greatly reduced.

以下、本発明を詳しく説明する。
本発明の廃液の減量方法は、無機塩を含有する廃液を濃縮して濃縮廃液とし、濃縮廃液から無機塩の一部を晶析させ、次いで、固形状分と液状分とに分離することを特徴とする。
上記「廃液」は無機塩を含有するものであればどのような廃液であってもよく、無機塩を含有することを除いて特に限定はされない。
The present invention will be described in detail below.
The method for reducing the amount of waste liquid according to the present invention comprises concentrating a waste liquid containing an inorganic salt to obtain a concentrated waste liquid, crystallizing a part of the inorganic salt from the concentrated waste liquid, and then separating the solid salt into a liquid component. Features.
The “waste liquid” may be any waste liquid as long as it contains an inorganic salt, and is not particularly limited except that it contains an inorganic salt.

上記「無機塩」は特に限定されないが、例えば、硫酸ナトリウム、塩化ナトリウム、亜硫酸ナトリウム及び亜硝酸ナトリウム等が挙げられる。これらの無機塩は酸洗、脱硫等の操作にともなって発生するアルカリ性又は酸性の廃液を酸又はアルカリにより中和するときなどに生成し、多くの廃液に含有されている。これらの無機塩は廃液に1種のみ含有されていることもあり、2種以上含有されていることもある。   The “inorganic salt” is not particularly limited, and examples thereof include sodium sulfate, sodium chloride, sodium sulfite, and sodium nitrite. These inorganic salts are produced when an alkaline or acidic waste liquid generated by operations such as pickling and desulfurization is neutralized with an acid or alkali, and are contained in many waste liquids. Only one of these inorganic salts may be contained in the waste liquid, or two or more thereof may be contained.

上記「濃縮」では、廃液を無機塩の飽和濃度以下の濃度範囲で濃縮してもよく、飽和濃度を越えて濃縮し、直接無機塩を晶析させてもよい。廃液は、含有される無機塩(無機塩は廃液に溶解しているが、本明細書では、これを無機塩が廃液に含有されているという。)の飽和濃度以下の濃度範囲で濃縮され、又は飽和濃度を越えて濃縮され、上記「濃縮廃液」とされる。廃液をどの程度濃縮するかは特に限定されないが、濃縮の程度が低すぎると廃液を十分に減量させることができないため好ましくない。一方、濃縮の程度が高くなるほど、分離後の固形状分に有害物等が混入し易くなる。特に、固形状分から硫酸ナトリウム等の有用な無機塩を回収し、再利用する場合は、回収された無機塩に含有される有害物及び不純物等を除くため、より十分に精製等をする必要が生じる。   In the above “concentration”, the waste liquid may be concentrated in a concentration range below the saturation concentration of the inorganic salt, or may be concentrated beyond the saturation concentration to directly crystallize the inorganic salt. The waste liquid is concentrated in a concentration range equal to or lower than the saturation concentration of the contained inorganic salt (the inorganic salt is dissolved in the waste liquid, but in this specification, the inorganic salt is contained in the waste liquid). Or it concentrates exceeding a saturated density | concentration and is set as the said "concentrated waste liquid." The degree of concentration of the waste liquid is not particularly limited, but if the degree of concentration is too low, it is not preferable because the waste liquid cannot be reduced sufficiently. On the other hand, as the degree of concentration increases, harmful substances and the like are easily mixed into the solid after separation. In particular, when a useful inorganic salt such as sodium sulfate is recovered from a solid content and reused, it is necessary to purify it sufficiently in order to remove harmful substances and impurities contained in the recovered inorganic salt. Arise.

上記「晶析」では、濃縮廃液に含有されていた無機塩の一部を晶析させる。晶析の方法は特に限定されず、濃縮廃液の温度を低下させる等の方法が挙げられる。晶析させる無機塩の、無機塩の全量に対する質量割合も特に限定されず、この質量割合は晶析時の温度等によって調整することができる。この質量割合は、無機塩の全量を100質量%とした場合に、固形状分に含有される無機塩が、60〜90質量%、特に70〜80質量%となる質量割合であることが好ましい。固形状分に含有される無機塩が全量の60〜90質量%であれば、この無機塩を回収することにより、残部の処理すべき廃液を十分に減量させることができる。また、無機塩が有用なものであり、これを回収する場合に、有害物等の混入の少ないより商品価値の高い再利用品とすることができる。
尚、廃液を濃縮せず、温度を低下させる等の方法により無機塩の一部を晶析させることもできる。このようにして晶析させ、その後、廃液を濃縮する場合と同様にして、固形状分と液状分とに分離し、固形状分を除去することによって廃液を減量させることもできる。
In the above “crystallization”, a part of the inorganic salt contained in the concentrated waste liquid is crystallized. The method of crystallization is not particularly limited, and examples thereof include a method of reducing the temperature of the concentrated waste liquid. The mass ratio of the inorganic salt to be crystallized with respect to the total amount of the inorganic salt is not particularly limited, and this mass ratio can be adjusted by the temperature at the time of crystallization. This mass proportion is preferably such that the inorganic salt contained in the solid component is 60 to 90 mass%, particularly 70 to 80 mass% when the total amount of inorganic salt is 100 mass%. . When the inorganic salt contained in the solid content is 60 to 90% by mass of the total amount, the remaining waste liquid to be treated can be sufficiently reduced by collecting the inorganic salt. In addition, an inorganic salt is useful, and when it is recovered, it can be made into a recycled product having a higher commercial value than a mixture of harmful substances.
A part of the inorganic salt can be crystallized by a method such as reducing the temperature without concentrating the waste liquid. In the same manner as in the case of crystallization in this way, and then concentrating the waste liquid, the solid can be separated into a liquid and a liquid, and the liquid can be reduced by removing the solid.

濃縮廃液の上記「分離」の方法は特に限定されず、例えば、遠心分離及び沈降分離等の各種の方法が挙げられる。この分離によって濃縮廃液は上記「固形状分」と上記「液状分」とに分離される。濃縮廃液には相当量の液状分(水分)が残存しているため、分離後の固形状分には水分が付着、含有されており、無機塩が有用なものであるときは、洗浄、精製及び乾燥等の処理を施して回収することができる。また、有害物等が固形状分に混入し難いため、回収される無機塩の品質を高めることができる。一方、無機塩が無用なものであるときは、廃棄物として処分することになる。   The method of “separation” of the concentrated waste liquid is not particularly limited, and examples thereof include various methods such as centrifugation and sedimentation separation. By this separation, the concentrated waste liquid is separated into the “solid component” and the “liquid component”. Since a considerable amount of liquid content (water) remains in the concentrated waste liquid, the solid content after separation contains and contains water, and when inorganic salts are useful, washing and purification And it can collect | recover by giving processes, such as drying. Moreover, since harmful substances and the like are hardly mixed into the solid content, the quality of the recovered inorganic salt can be improved. On the other hand, when the inorganic salt is useless, it is disposed as waste.

濃縮は一度のみでもよいが、分離後の液状分を更に濃縮してもよい。これにより処理すべき廃液をより減量させることができる。この再濃縮も、液状分を無機塩の飽和濃度以下の濃度範囲で実施してもよく、飽和濃度を越えて濃縮し、無機塩を晶析させてもよい。また、液状分を再濃縮し、その後、一度目の濃縮の後工程と同様にして無機塩を晶析させ、更に固形状分と液状分とに分離させることもできる。これにより、処理すべき廃液をより減量させることができる。更に、この固形状分からは、一度目の濃縮のときと同様にして有用な無機塩を回収することができ、無用な無機塩は同様に廃棄物として処分することになる。このように、液状分の濃縮と無機塩の回収を繰り返すことにより、処理すべき廃液を更に減量させることができる。   Concentration may be performed only once, but the liquid after separation may be further concentrated. As a result, the amount of waste liquid to be treated can be further reduced. This reconcentration may also be carried out in a concentration range that is not more than the saturation concentration of the inorganic salt, or may be concentrated beyond the saturation concentration to crystallize the inorganic salt. Further, the liquid component can be re-concentrated, and then the inorganic salt can be crystallized in the same manner as in the post-concentration step for the first time, and further separated into a solid component and a liquid component. Thereby, the waste liquid which should be processed can be reduced more. Further, useful inorganic salts can be recovered from the solid content in the same manner as in the first concentration, and unnecessary inorganic salts are similarly disposed as waste. Thus, the waste liquid to be treated can be further reduced by repeating the concentration of the liquid and the recovery of the inorganic salt.

無機塩が硫酸ナトリウムである場合、この硫酸ナトリウムは、硫酸を含有する廃液を水酸化ナトリウムにより中和した廃液、又は水酸化ナトリウムを含有する廃液を硫酸により中和した廃液等に含有され、この廃液は酸洗等にともなって産業界では多量に発生する廃液の一種である。この硫酸ナトリウムは、ガラス、パルプ等の製造、洗剤のビルダー、及び染料の希釈剤等の用途があり、無水物は吸湿性があるため、有機溶媒の乾燥剤等としても用いられる。このように硫酸ナトリウムは廃液に含有される無機塩のうちでは有用なものであり、再利用の対象となる無機塩である。   When the inorganic salt is sodium sulfate, the sodium sulfate is contained in a waste liquid obtained by neutralizing a waste liquid containing sulfuric acid with sodium hydroxide or a waste liquid obtained by neutralizing a waste liquid containing sodium hydroxide with sulfuric acid. Waste liquid is a kind of waste liquid that is generated in large quantities in the industry due to pickling. This sodium sulfate has uses such as glass and pulp production, detergent builders, and dye diluents, and the anhydride is hygroscopic, and is also used as a desiccant for organic solvents. As described above, sodium sulfate is useful among the inorganic salts contained in the waste liquid, and is an inorganic salt to be reused.

廃液からの硫酸ナトリウムの回収は、これまで十水和物及び無水物の各々の回収に適した廃液を用いてなされており、それぞれ特定の廃液が用いられてきたが、本発明の廃液の減量方法では、廃液の種類は特定されず、且つ無機塩として硫酸ナトリウムが含有される同一の廃液から十水和物及び無水物を回収することができる。即ち、濃縮廃液から硫酸ナトリウム十水和物を晶析させ、その後、この十水和物を用いて硫酸ナトリウム無水物を生成させることができる。硫酸ナトリウムは32.4℃以下の温度では十水和物が安定であり、32.4℃を越えると無水物が安定である。従って、32.4℃以下の温度範囲で濃縮廃液から硫酸ナトリウムを晶析させると十水和物が得られ、その後、32.4℃を越える温度範囲に昇温させて回収操作をすることにより容易に硫酸ナトリウム無水物として回収することができる。また、硫酸ナトリウムを十水和物として晶析させるときの温度は32.4℃以下であればよいが、0〜30℃、特に0〜25℃、更に3〜20℃とすることができる。更に、無水物として回収するときの温度は32.4℃を越えておればよいが、40〜90℃、特に50〜85℃、更に60〜80℃とすることができる。
尚、廃液から同様にして回収することができる無機塩としては、硫酸ナトリウムの他に塩化ナトリウム等が挙げられる。
The recovery of sodium sulfate from waste liquid has so far been performed using waste liquids suitable for recovery of decahydrate and anhydride, and specific waste liquids have been used, respectively. In the method, the type of waste liquid is not specified, and decahydrate and anhydride can be recovered from the same waste liquid containing sodium sulfate as an inorganic salt. That is, sodium sulfate decahydrate can be crystallized from the concentrated waste liquid, and then sodium sulfate anhydride can be produced using this decahydrate. Sodium sulfate is stable in decahydrate at a temperature of 32.4 ° C. or lower, and anhydrous in stable at temperatures higher than 32.4 ° C. Therefore, when sodium sulfate is crystallized from the concentrated waste liquid in a temperature range of 32.4 ° C. or less, decahydrate is obtained, and then the temperature is raised to a temperature range exceeding 32.4 ° C. It can be easily recovered as sodium sulfate anhydride. Moreover, although the temperature when crystallizing sodium sulfate as a decahydrate should just be 32.4 degrees C or less, it can be 0-30 degreeC, especially 0-25 degreeC, Furthermore, it can be 3-20 degreeC. Furthermore, although the temperature at the time of collect | recovering as an anhydride should just exceed 32.4 degreeC, it can be set to 40-90 degreeC, especially 50-85 degreeC, Furthermore, 60-80 degreeC.
In addition, examples of the inorganic salt that can be similarly recovered from the waste liquid include sodium chloride in addition to sodium sulfate.

更に、十水和物は晶析の際に多量の水をともなうため(NaSOの分子量は134であり、水和する水の式量は180である。)、濃縮廃液から硫酸ナトリウム十水和物を晶析させるときに、硫酸ナトリウムの分離とともに多量の水が固形状分に移行する。これによって、処理すべき廃液を極めて効率よく減量させることができる。且つ冷却により溶解度の差を利用して回収するため、液状分に含有される有害物等の不純物の濃縮が少なく、固形状分に付着して持ち出される不純物も少なくなる。このようにして回収された硫酸ナトリウム十水和物であるため、この十水和物を用いて硫酸ナトリウム無水物を生成させることにより、廃液の種類によらず、より高純度の硫酸ナトリウム無水物を得ることができる。また、不純物量の少ない硫酸ナトリウム十水和物を加熱濃縮して無水物を回収する際に蒸発する水分は純度が高く、純水製造原料としての利用も可能となる。 Furthermore, since decahydrate is accompanied by a large amount of water during crystallization (Na 2 SO 4 has a molecular weight of 134 and the formula amount of water to be hydrated is 180), sodium sulfate-rich water is concentrated from the concentrated waste liquid. When the hydrate is crystallized, a large amount of water moves into a solid content along with the separation of sodium sulfate. As a result, the amount of waste liquid to be processed can be reduced extremely efficiently. In addition, since the recovery is performed by utilizing the difference in solubility by cooling, the concentration of impurities such as harmful substances contained in the liquid content is small, and the impurities that adhere to the solid content are also reduced. Since it is sodium sulfate decahydrate recovered in this way, by using this decahydrate to produce sodium sulfate anhydrous, regardless of the type of waste liquid, higher purity sodium sulfate anhydrous Can be obtained. In addition, water evaporated when sodium sulfate decahydrate having a small amount of impurities is concentrated by heating to recover an anhydride has high purity, and can be used as a raw material for producing pure water.

本発明の廃液の処理方法は、無機塩を含有する廃液の処理方法であって、本発明の廃液の減量方法における減量工程を備えることを特徴とする。
この廃液の処理方法では、濃縮廃液から無機塩を晶析させ、その後、分離し、得られる固形状分及び液状分のいずれからも、精製及び/又は加工等により有用な無機塩を回収することができる。
尚、この廃液の処理方法における無機塩、濃縮、濃縮廃液、晶析、固形状分、液状分及び分離の各々については、前記の廃液の減量方法におけるそれぞれに関する記載をそのまま適用することができる。
The waste liquid treatment method of the present invention is a waste liquid treatment method containing an inorganic salt, and is characterized by comprising a weight reduction step in the waste liquid reduction method of the present invention.
In this waste liquid treatment method, the inorganic salt is crystallized from the concentrated waste liquid, and then separated, and the useful inorganic salt is recovered by purification and / or processing etc. from both the solid and liquid components obtained. Can do.
In addition, about each of the inorganic salt, concentration, concentrated waste liquid, crystallization, solid content, liquid content, and separation in this waste liquid treatment method, the description regarding each of the waste liquid reduction methods can be applied as it is.

濃縮廃液からは、例えば、前記のようにして、硫酸ナトリウムを十水和物又は無水物の形態で回収し、再利用することができる。また、同様に、洗浄、精製等により塩化ナトリウム等を回収し、再利用することもできる。   From the concentrated waste liquid, for example, as described above, sodium sulfate can be recovered in the form of decahydrate or anhydride and reused. Similarly, sodium chloride or the like can be recovered and reused by washing, purification, or the like.

また、液状分が硫酸イオンを含有する場合、この液状分にカルシウム化合物を添加して汚泥を生成させ、その後、この汚泥を脱水して脱水物とし、この脱水物、即ち、硫酸カルシウムを回収し、セメント原料として再利用することができる。カルシウム化合物としては、酸化カルシウム、水酸化カルシウム、炭酸カルシウム、石灰乳等を用いることができ、これらは単独で用いてもよく、2種以上を混合して用いてもよい。前記のように、硫酸ナトリウム等の硫酸イオンが含有される廃液は多量に発生しており、従って、多くの廃液から分離された液状分に硫酸イオンが含有されている。本発明の廃液の処理方法では、この液状分から硫酸カルシウムを回収することにより、硫酸ナトリウム等が回収された後の液状分に残存する硫酸イオンも有効に活用することができ、廃液に含有される有用な無機塩等のほとんど全てを回収し、有効に再利用することができる。尚、カルシウム化合物として石灰乳等の水溶液を用いたときは、必ずしも廃液の減量につながらないこともあるが、用いるカルシウム化合物の種類によっては、液状分から硫酸カルシウムを回収し、セメント原料として再利用することにより、処理すべき廃液の減量とともに、処理すべき固形状分を減量することもでき、処理量の総量を減量することもできる。   In addition, when the liquid component contains sulfate ions, a calcium compound is added to the liquid component to produce sludge, and then the sludge is dehydrated to obtain a dehydrated product, and the dehydrated product, that is, calcium sulfate is recovered. It can be reused as a cement raw material. As the calcium compound, calcium oxide, calcium hydroxide, calcium carbonate, lime milk and the like can be used, and these may be used alone or in admixture of two or more. As described above, a large amount of waste liquid containing sulfate ions such as sodium sulfate is generated. Therefore, sulfate ions are contained in a liquid component separated from many waste liquids. In the waste liquid treatment method of the present invention, by recovering calcium sulfate from this liquid content, sulfate ions remaining in the liquid content after sodium sulfate or the like is recovered can also be effectively used and contained in the waste liquid. Almost all useful inorganic salts can be recovered and reused effectively. Note that when an aqueous solution such as lime milk is used as the calcium compound, it may not necessarily reduce the amount of waste liquid, but depending on the type of calcium compound used, calcium sulfate may be recovered from the liquid and reused as a cement raw material. As a result, the amount of waste liquid to be processed can be reduced, the solid content to be processed can be reduced, and the total amount of the processed amount can also be reduced.

上記の硫酸カルシウムの回収は、特定の設備、操作等を必要とするため、酸洗、脱硫等をする工場内等では実施されず、通常、廃液処理を専業とする事業所等で実施される。そのため、減量された廃液の減量工程を実施した場所、即ち、廃液が発生した事業所等から廃液処理を専業とする事業所等の他場所に専用の車両等により運搬し、その後、カルシウム化合物の添加、汚泥の脱水、及び硫酸カルシウムの回収がなされることが多く、この硫酸カルシウムがセメント原料として再利用される。また、廃液の減量を実施する場所と硫酸カルシウムの回収を実施する場所との間が近距離であるときは、配管等により移送することもできる。このように、廃液(液状分)を運搬し、又は移送する必要があるため、処理すべき廃液を減量することは、回収し、再利用される硫酸カルシウムのコストの観点でも極めて有利である。
以上、詳述したように、本発明の廃液の処理方法では、処理すべき廃液が十分に減量され、専用の車両等により運送するにしても、配管等により移送するにしても、搬送費用を大きく低減させることができ、且つ廃液に含有される成分のうちの多くを効率よく回収し、高品質の商品価値の高い再利用品とすることができ、総体的にみて極めて有用なリサイクルシステムであるといえる。
The above-mentioned recovery of calcium sulfate requires specific equipment, operation, etc., so it is not carried out in factories where pickling and desulfurization are carried out, and is usually carried out in establishments that specialize in waste liquid treatment. . Therefore, it is transported by a dedicated vehicle etc. to the place where the waste liquid reduction process is carried out, that is, the place where the waste liquid is generated, etc. Addition, sludge dehydration, and recovery of calcium sulfate are often performed, and this calcium sulfate is reused as a cement raw material. Further, when the place where the waste liquid is reduced and the place where the calcium sulfate is recovered is a short distance, it can be transferred by piping or the like. As described above, since it is necessary to transport or transfer the waste liquid (liquid component), reducing the amount of the waste liquid to be treated is extremely advantageous from the viewpoint of the cost of calcium sulfate to be recovered and reused.
As described above in detail, in the waste liquid processing method of the present invention, the waste liquid to be processed is sufficiently reduced, and even if transported by a dedicated vehicle or the like or transported by piping or the like, the transportation cost is reduced. It is a very useful recycling system as a whole because it can be greatly reduced, and many of the components contained in the waste liquid can be efficiently recovered, resulting in a high-quality, highly reusable product. It can be said that there is.

以下、実施例により本発明を具体的に説明する。
本実施例で使用した試料廃液は、100g当たり、硫酸ナトリウムを17.0g、炭酸ナトリウム2.0g、塩化ナトリウムを1.0g、フッ化ナトリウム1.0g及びリン酸第二鉄を1.0g含有しており、比重が1.15(15℃)の廃液である。
Hereinafter, the present invention will be described specifically by way of examples.
The sample waste solution used in this example contains 17.0 g of sodium sulfate, 2.0 g of sodium carbonate, 1.0 g of sodium chloride, 1.0 g of sodium fluoride and 1.0 g of ferric phosphate per 100 g. The waste liquid has a specific gravity of 1.15 (15 ° C.).

実施例1
試料廃液を濃縮して濃縮廃液とし、その後、濃縮廃液を15℃に冷却し、硫酸ナトリウム十水和物を析出させた。析出した結晶を遠心分離により液状分と分離して回収し、表面を水により洗浄した。結晶を回収した後の液状分と洗浄水とを混合し、その後、この混合液を濃縮廃液と同比重まで濃縮し、減量化させた。次いで、濃縮液を5℃に冷却し、上記の工程を繰り返した。これにより処理すべき廃液を十分に減量させることができた。
Example 1
The sample waste liquid was concentrated to obtain a concentrated waste liquid, and then the concentrated waste liquid was cooled to 15 ° C. to precipitate sodium sulfate decahydrate. The precipitated crystals were separated from the liquid component by centrifugation and collected, and the surface was washed with water. The liquid after recovering the crystals was mixed with the washing water, and then this mixed solution was concentrated to the same specific gravity as the concentrated waste liquid to reduce the amount. The concentrate was then cooled to 5 ° C. and the above process was repeated. As a result, the amount of waste liquid to be treated could be reduced sufficiently.

実施例2
試料廃液を減圧下70℃で濃縮して硫酸ナトリウム無水物を析出させた。析出した結晶を遠心分離により液状分と分離して回収し、表面を70℃の温水により洗浄した。結晶を回収した後の液状分と洗浄水とを混合し、その後、この混合液を濃縮廃液と同比重まで濃縮し、減量化させた。次いで、濃縮、減量化させた液を用いて上記の工程を繰り返した。これにより処理すべき廃液を十分に減量させることができた。
Example 2
The sample waste liquid was concentrated at 70 ° C. under reduced pressure to precipitate sodium sulfate anhydride. The precipitated crystals were separated from the liquid component by centrifugation and collected, and the surface was washed with hot water at 70 ° C. The liquid after recovering the crystals was mixed with the washing water, and then this mixed solution was concentrated to the same specific gravity as the concentrated waste liquid to reduce the amount. Next, the above steps were repeated using the concentrated and reduced liquid. As a result, the amount of waste liquid to be treated could be reduced sufficiently.

実施例3
実施例1で回収した硫酸ナトリウム十水和物100質量部に対して50質量部の水を添加して再溶解させ、その後、水溶液を加温して70℃に昇温させ、次いで、濃縮して硫酸ナトリウム無水物の結晶を析出させた。その後、析出した結晶を回収し、表面を70℃の温水により洗浄した。次いで、結晶を回収した後の液状分と洗浄水とを混合し、再び濃縮し、減量させた。
以上、実施例1〜3の各々における廃液の減量率を算出し、回収した硫酸ナトリウムの組成を蛍光X線により分析した。結果は表1のとおりである。
Example 3
50 parts by mass of water was added to 100 parts by mass of sodium sulfate decahydrate recovered in Example 1 and redissolved. Thereafter, the aqueous solution was heated to 70 ° C. and then concentrated. In this way, crystals of sodium sulfate anhydride were precipitated. Thereafter, the precipitated crystals were collected, and the surface was washed with warm water at 70 ° C. Next, the liquid after recovering the crystals and the washing water were mixed and concentrated again to reduce the amount.
As mentioned above, the reduction | decrease rate of the waste liquid in each of Examples 1-3 was computed, and the composition of the collect | recovered sodium sulfate was analyzed with the fluorescent X ray. The results are shown in Table 1.

Figure 2008272687
Figure 2008272687

表1の結果によれば、実施例1〜3のいずれの場合も、多くのSO及びNaOが検出され、Cl、F等の有害物及び微量不純物等は極く僅かであり、品質の高い硫酸ナトリウム十水和物又は無水物が回収されていることが分かる。特に、硫酸ナトリウム十水和物を回収し、その後、この十水和物を用いて硫酸ナトリウム無水物を生成させた実施例3では、より高純度の硫酸ナトリウムを得ることができた。 According to the results of Table 1, in any of Examples 1 to 3, a large amount of SO 3 and Na 2 O were detected, and harmful substances such as Cl and F, trace impurities, and the like were very little. It can be seen that high sodium sulfate decahydrate or anhydride is recovered. In particular, in Example 3 in which sodium sulfate decahydrate was collected and then sodium sulfate anhydride was produced using this decahydrate, higher-purity sodium sulfate could be obtained.

Claims (10)

無機塩を含有する廃液を濃縮して濃縮廃液とし、該濃縮廃液から該無機塩の一部を晶析させ、次いで、固形状分と液状分とに分離することを特徴とする廃液の減量方法。   A waste liquid reduction method comprising concentrating a waste liquid containing an inorganic salt to obtain a concentrated waste liquid, crystallizing a part of the inorganic salt from the concentrated waste liquid, and then separating it into a solid part and a liquid part . 上記液状分を再濃縮する請求項1に記載の廃液の減量方法。   The method for reducing the amount of waste liquid according to claim 1, wherein the liquid is re-concentrated. 上記無機塩を100質量%とした場合に、上記固形状分に含有される該無機塩は60〜90質量%である請求項1又は2に記載の廃液の減量方法。   The method for reducing the amount of waste liquid according to claim 1 or 2, wherein the inorganic salt is 60 to 90 mass% when the inorganic salt is 100 mass%. 上記無機塩が、硫酸ナトリウム、塩化ナトリウム、亜硫酸ナトリウム及び亜硝酸ナトリウムのうちの少なくとも1種である請求項1乃至3のうちのいずれか1項に記載の廃液の減量方法。   The method for reducing the amount of waste liquid according to any one of claims 1 to 3, wherein the inorganic salt is at least one of sodium sulfate, sodium chloride, sodium sulfite, and sodium nitrite. 上記無機塩が硫酸ナトリウムであり、該硫酸ナトリウムが、硫酸を含有する廃液を水酸化ナトリウムにより中和した廃液、又は水酸化ナトリウムを含有する廃液を硫酸により中和した廃液に含有されるものである請求項1乃至4うちのいずれか1項に記載の廃液の減量方法。   The inorganic salt is sodium sulfate, and the sodium sulfate is contained in a waste liquid obtained by neutralizing a waste liquid containing sulfuric acid with sodium hydroxide, or a waste liquid obtained by neutralizing a waste liquid containing sodium hydroxide with sulfuric acid. The method for reducing the amount of waste liquid according to any one of claims 1 to 4. 上記固形状分に含有される上記無機塩を精製し、及び/又は加工し、再利用する請求項1乃至5のうちのいずれか1項に記載の廃液の減量方法。   The method for reducing the amount of waste liquid according to any one of claims 1 to 5, wherein the inorganic salt contained in the solid component is purified and / or processed and reused. 上記無機塩が硫酸ナトリウムであり、上記濃縮廃液から硫酸ナトリウム十水和物を晶析させ、その後、該硫酸ナトリウム十水和物を用いて硫酸ナトリウム無水物を生成させる請求項6に記載の廃液の減量方法。   The waste liquid according to claim 6, wherein the inorganic salt is sodium sulfate, and sodium sulfate decahydrate is crystallized from the concentrated waste liquid, and then sodium sulfate anhydrous is produced using the sodium sulfate decahydrate. Weight loss method. 無機塩を含有する廃液の処理方法であって、
請求項1乃至7のうちのいずれか1項に記載の廃液の減量方法における減量工程を備えることを特徴とする廃液の処理方法。
A method for treating a waste liquid containing an inorganic salt,
A waste liquid treatment method comprising a weight reduction step in the waste liquid reduction method according to any one of claims 1 to 7.
上記液状分が硫酸イオンを含有し、該液状分にカルシウム化合物を添加して汚泥を生成させ、その後、該汚泥を脱水して脱水物とし、該脱水物をセメント原料として用いる請求項8に記載の廃液の処理方法。   The liquid component contains sulfate ions, and a calcium compound is added to the liquid component to generate sludge. Thereafter, the sludge is dehydrated to obtain a dehydrated product, and the dehydrated product is used as a cement raw material. Waste liquid treatment method. 上記液状分が硫酸イオンを含有し、該液状分を上記減量工程がなされる場所から他場所に運搬し、その後、該液状分にカルシウム化合物を添加して汚泥を生成させ、次いで、該汚泥を脱水して脱水物とし、該脱水物をセメント原料として用いる請求項8に記載の廃液の処理方法。   The liquid content contains sulfate ions, and the liquid content is transported from the place where the weight reduction process is performed to another place, and then a calcium compound is added to the liquid content to generate sludge. The method for treating a waste liquid according to claim 8, wherein the dehydrated product is dehydrated to be used as a cement raw material.
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JP2009136843A (en) * 2007-12-10 2009-06-25 Daiseki:Kk Method of treating waste liquid
KR20140128272A (en) * 2013-04-26 2014-11-05 콘 프로덕츠 디벨롭먼트, 인크. Elimination of sodium sulfate from biologically treated wastewater
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009136843A (en) * 2007-12-10 2009-06-25 Daiseki:Kk Method of treating waste liquid
KR20140128272A (en) * 2013-04-26 2014-11-05 콘 프로덕츠 디벨롭먼트, 인크. Elimination of sodium sulfate from biologically treated wastewater
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CN114804396A (en) * 2021-01-28 2022-07-29 无锡中天固废处置有限公司 High-salinity lye pool wastewater treatment process
CN114804396B (en) * 2021-01-28 2023-04-07 无锡中天固废处置有限公司 High-salinity lye pool wastewater treatment process

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