JP4567303B2 - Method for treating arsenic-containing sulfuric acid - Google Patents
Method for treating arsenic-containing sulfuric acid Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は、ヒ素含有硫酸の処理方法に関し、詳しくは、１０００ｐｐｍ以下、特に、５００ｐｐｍ以下の希薄濃度のヒ素を含有する硫酸からヒ素を固形化して除去する方法に関する。
【０００２】
【従来の技術】
数千〜数万ｐｐｍのヒ素を含有する鉱酸、例えば硫酸からヒ素を１０ｐｐｍ以下までに除去する方法として、ヒ素含有硫酸に水溶性硫化物や硫化水素ガスを添加し、硫酸中のヒ素を硫化ヒ素として不溶化させた後、これを硫酸中から固液分離する方法が一般的に行われている。しかし、ヒ素濃度が１０００ｐｐｍ以下の希薄ヒ素を含有する鉱酸の場合は、硫化ヒ素の結晶生成が極めて遅くなり、鉱酸中のヒ素を一定濃度以下に除去するために数日間という比較的長時間を要し、実用性に難点がある。また、鉱酸中のヒ素を一定濃度以下にまで除去した後も、鉱酸中に残存するヒ素と硫化物とが反応し、沈降しにくい微細な硫化ヒ素が析出し続けるという問題がある。
【０００３】
このため、希薄なヒ素を含有する鉱酸廃液は、従来は再利用せずに廃液処理して排出しているのが実情である。廃液処理の方法として、例えば、希薄ヒ素含有鉱酸廃液のｐＨを７以上に調整して硫化ヒ素を形成させた後、鉄塩化合物を加えて凝集沈殿させる方法が知られている（例えば、特許文献１参照。）。
【０００４】
【特許文献１】
特開平１１−２７７０７５号公報
【０００５】
【発明が解決しようとする課題】
しかしながら、希薄ヒ素含有鉱酸廃液のｐＨを７以上にするためには、多大なアルカリ性物質が必要であり、また、ヒ素を含有した沈殿物の量が鉄塩等の凝集剤の添加によって大きく増加するため、ヒ素含有沈殿物の最終処分コストが大きくなるなどの問題を抱えていた。
【０００６】
そこで本発明は、ヒ素濃度が１０００ｐｐｍ以下の希薄ヒ素を含有した硫酸からヒ素を効率よく除去することができるヒ素含有硫酸の処理方法を提供することを目的としている。
【０００７】
【課題を解決するための手段】
上記目的を達成するため、本発明のヒ素含有硫酸の処理方法は、ヒ素濃度が１０００ｐｐｍ以下である希薄ヒ素を含有する硫酸からヒ素を除去するヒ素含有硫酸の処理方法であって、２ｇ／Ｌ以上の割合で添加した固形硫化ヒ素の存在下で前記希薄ヒ素含有硫酸に硫化ナトリウム水溶液及び／又は水硫化ナトリウム水溶液を、ヒ素に対する硫黄の重量比が１〜１０の間になるように添加してヒ素を固形硫化ヒ素に変換し、次いで固液分離手段により前記固形硫化ヒ素を除去することを特徴としている。
【０００８】
本発明の処理対象となるヒ素含有硫酸は、希薄濃度のヒ素を含有する硫酸溶液であり、具体的には、ヒ素濃度が１０００ｐｐｍ以下、特に５００ｐｐｍ以下の硫酸溶液である。前記硫酸の酸濃度は特に限定されない。また、ヒ素以外の不純物を含有している硫酸であっても、その不純物が硫化ヒ素の形成を阻害するものでなければよい。
【０００９】
このようなヒ素含有硫酸としては、例えば、鉱山排水、精錬工場のプロセス排水、化学工業、電子工業の排水等を挙げることができる。また、水に含まれるヒ素をヒ素吸着材に吸着させることによって水中からヒ素を除去する水処理において、ヒ素を吸着したヒ素吸着材を硫酸で再生したときに発生するヒ素含有硫酸廃液や、硫酸で処理したヒ素吸着材を水洗するときに発生する水洗水も本発明の処理対象となる。
【００１０】
処理対象のヒ素含有硫酸は、そのｐＨが４以下、特に、ｐＨ３以下であることが望ましい。ヒ素含有硫酸のｐＨが４を超えている場合は、適当な酸、通常は同種の硫酸を使用してｐＨを調整すべきである。
【００１１】
このようなヒ素含有硫酸からヒ素を除去するにあたり、該ヒ素含有硫酸を、固形硫化ヒ素の存在下でヒ素含有硫酸に硫化ナトリウム水溶液及び／又は水硫化ナトリウム水溶液を添加する。このように、固形硫化ヒ素及び／又は硫黄が存在する状態で、硫酸中に溶存しているヒ素を硫化ナトリウムや水硫化ナトリウムと接触させることにより、硫化ヒ素の析出を促進することができるとともに、後段の固液分離も容易となる。このとき、固形硫化物、例えば硫化銅を用いると、硫化ヒ素の結晶生成に寄与しないだけでなく、自ら溶解して銅イオンを放出するため好ましくない。
【００１２】
前記固形硫化ヒ素は、固形であれば形状は問わないが、後段の固液分離を考慮すると、平均粒径が０．１ｍｍ以上のものが好ましい。固形硫化ヒ素の添加方法は、粉末状の形でそのまま添加してもよいし、加水してスラリー状で添加してもよい。固形硫化ヒ素の添加量は、ヒ素含有硫酸の処理量に比例し、１Ｌ／ｈｒのヒ素含有硫酸処理量に対して、固形硫化ヒ素は、１ｇ以上、好ましくは２ｇ以上、特に４ｇ以上であることが好ましい。
【００１３】
硫化剤として用いられる前記硫化ナトリウム及び／又は水硫化ナトリウムは、市販の硫化ナトリウムや水硫化ナトリウムを使用することができる。硫化剤として硫化ナトリウム及び／又は水硫化ナトリウムを用いることにより、硫酸中での反応で硫化ヒ素が生成し、あらかじめ添加された固形硫化ヒ素を種結晶としてその表面に析出し、後段の固液分離装置で容易に除去可能な状態となる。
【００１４】
硫化剤（硫化ナトリウム及び／又は水硫化ナトリウム）の添加量は、少なくとも生成される硫化ヒ素に必要な硫黄当量以上であることが必要であるが、当量より多少過剰に添加したほうが反応速度は大きくなる。しかし、大過剰に添加しては無駄になるので、ヒ素に対する硫黄の重量比が１〜１０の間になるように硫化剤の添加量を設定する。
【００１５】
ヒ素含有硫酸と硫化剤との接触時間は１０分以上、好ましくは１５分以上である。接触時間が１０分未満の場合は、ヒ素除去率が不十分になることがある。硫化剤と接触させる際のヒ素含有硫酸の温度は、２０〜９０℃の範囲が適当であり、特に、３０〜６０℃の範囲が好ましい。温度が高いほど反応速度が速くなり、除去率が向上して短時間で処理を終えることができるが、温度を高くし過ぎると加熱のために多くのエネルギーを必要とするため、コスト的に問題となることがある。
【００１６】
固形硫化ヒ素の存在下でヒ素含有硫酸と硫化剤とを接触させるための固液接触装置には、従来から用いられている公知の装置を使用できる。固形硫化ヒ素は、固液接触装置内に滞留して固定床あるいは流動床を形成するようにしてもよく、原液に必要量を添加し、完全混合固液接触装置を経て後段の固液分離装置で分離するようにしてもよい。
【００１７】
生成した硫化ヒ素の結晶は、固液接触装置に固液分離機能を付加して分離してもよいが、結晶が小さくて沈降性が悪いため、固液接触装置の後段に固液分離装置を設け、この固液分離装置で確実に分離除去することが望ましい。固液分離装置としては、通常用いられている重力沈降やろ過等を含む公知の物理的固液分離装置を利用することができる。
【００１８】
このようにしてヒ素含有硫酸中からヒ素を効率よく除去できるが、硫化剤として使用した硫化ナトリウムや水硫化ナトリウムと硫酸とが反応して硫化水素ガスが生成し、この硫化水素ガスが処理後の硫酸中に溶存していることがある。処理硫酸中に硫化水素ガスが溶存していると、処理硫酸中に残留しているヒ素と反応して硫化ヒ素を生成したり、分解して硫黄を生成することがあるため、処理硫酸の後処理や再利用を行う際に不都合が発生することがある。
【００１９】
このように、処理硫酸中の硫化水素ガスの溶存が問題となる場合は、処理硫酸中から硫化水素ガスを除去する必要がある。処理硫酸からの硫化水素ガスの除去処理は、曝気処理、加熱処理、酸化処理及び減圧吸引処理のいずれか、あるいは、これらを適当に組み合わせて行うことができる。
【００２０】
曝気処理は、空気や窒素等の気体を用いた通常の曝気処理でよく、従来から用いられている種々の散気装置を用いて行うことができる。この曝気処理を行うことにより、処理硫酸中に溶存している硫化水素ガスは、散気空気等に同伴されて処理硫酸から除去され、あるいは、空気中の酸素によって酸化されて硫酸となる。この曝気処理の時間や散気量は、処理硫酸中の硫化水素溶存量や液温に応じて設定すればよい。
【００２１】
加熱処理は、前記固液接触処理の温度より高い温度に処理硫酸を保持し、硫化水素ガスの溶解度を低減することによって処理硫酸中から硫化水素ガスを放出させるものであり、加熱温度や処理時間は、処理硫酸中の硫化水素ガスの溶存量や液温に応じて設定することができるが、加熱温度は、通常は、５０℃以上が好ましい。
【００２２】
酸化処理は、酸素や過酸化水素等の酸化剤を処理硫酸に添加し、処理硫酸中の硫化水素ガスを酸化剤で酸化して硫酸とすることにより、処理硫酸中から硫化水素ガスを除去するものである。酸化剤の使用量は、処理硫酸中の硫化水素ガスの溶存量に応じて設定すればよい。
【００２３】
減圧吸引処理は、真空ポンプ等を使用して処理硫酸を減圧環境に保持し、硫化水素ガスの溶解度を低減させることによって処理硫酸中から硫化水素ガスを放出させるものである。このときの圧力や処理時間は、処理硫酸中の硫化水素ガスの溶存量や液温に応じて設定することができる。
【００２４】
また、本発明方法でヒ素を除去した処理硫酸中のヒ素濃度は、数ｐｐｍ〜数十ｐｐｍとなる。この濃度は、排水の放出基準である０．１ｐｐｍを満たすものではなく、処理硫酸を外部へ排出するためには、さらに第２の処理を行う必要がある。この第２の処理としては、ヒ素吸着材を用いた吸着や、凝集沈殿等の公知の方法を用いることができる。本発明の方法と第２の処理方法とを組み合わせることにより、第２の処理にかかるヒ素負荷が今までの数十分の一から数百分の一に大きく低減され、第２の処理装置の規模を小さくできるとともに、ヒ素含有沈殿物の発生量が大幅に低減し、処分コストの大幅な低減も図れる。さらに、本発明方法で生成して固液分離された硫化ヒ素は、純度が高く、再利用に繋がりやすいという利点もある。
【００２５】
【実施例】
実施例１及び比較例１
ヒ素（Ａｓ５＋）濃度１００ｍｇ／Ｌの２Ｎ硫酸５００ｍＬに、Ａｓ２Ｓ５スラリーを４ｇ／Ｌ（実施例１）、ＣｕＳスラリーを２０ｇ／Ｌ（比較例１）それぞれ添加し、５０℃に加温して硫化ナトリウム水溶液を滴下しながら４時間反応させた。硫化ナトリウムの添加量は、４００ｍｇ−Ｓ／Ｌになるよう調節した。その後、ろ紙で固液分離し、ろ液の硫酸中の残存Ａｓ濃度を測定した。各実験条件と測定結果とを表１にまとめて示す。
【００２６】
表１
実施例１ 比較例１
添加物 Ａｓ２Ｓ５ ＣｕＳ
添加物濃度 ４ｇ／Ｌ ２０ｇ／Ｌ
１L/hr処理量換算添加量 １６ｇ ８０ｇ
ヒ素除去率 87.3% ０％
【００２７】
比較例２
ヒ素（Ａｓ５＋）濃度１００ｍｇ／Ｌの２Ｎ硫酸２００ｍＬに、室温で水硫化ナトリウム水溶液を２１４ｍｇ−Ｓ／Ｌになるように添加した。次いで、ろ紙で固液分離し、ろ液の硫酸中の残存Ａｓ濃度を測定した。実験条件と測定結果を表２に示す。
【００２８】
表２
添加物 なし
添加物濃度 −
反応時間 ２４時間
１L/hr処理量換算添加量 −
硫化剤添加量 ２１４ｍｇ−Ｓ／Ｌ
反応温度 室温
ヒ素除去率 ４０．０％
【００２９】
実施例２，３
ヒ素（Ａｓ５＋）濃度１００ｍｇ／Ｌの２Ｎ硫酸５００ｍＬに、硫化ヒ素スラリーを表３の条件で添加し、室温（実施例２）、５０℃（実施例３）で水硫化ナトリウム水溶液を滴下しながら４時間反応させた。水硫化ナトリウムの添加量は、４００ｍｇ−Ｓ／Ｌになるように調節した。次いで、ろ紙で固液分離し、ろ液の硫酸中の残存Ａｓ濃度を測定した。実験条件と測定結果を表３にまとめて示す。
【００３０】
表３
実施例２ 実施例３
添加物 硫化ヒ素 硫化ヒ素
添加物濃度 ４ｇ／Ｌ ４ｇ／Ｌ
反応時間 ４時間 ４時間
１L/hr処理量換算添加量 １６ｇ １６ｇ
反応温度 室温 ５０℃
ヒ素除去率 65.4% 93.7%
【００３１】
【発明の効果】
以上説明したように、本発明のヒ素濃度が１０００ｐｐｍ以下、さらには５００ｐｐｍ以下の希薄ヒ素を含むヒ素含有硫酸の処理方法によれば、硫酸中に溶存しているヒ素を効率よく除去することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for treating arsenic-containing sulfuric acid , and more particularly to a method for solidifying and removing arsenic from sulfuric acid containing dilute arsenic of 1000 ppm or less, particularly 500 ppm or less.
[0002]
[Prior art]
As a method of removing arsenic from mineral acids containing thousands to tens of thousands of ppm of arsenic, for example, sulfuric acid to 10 ppm or less, water-soluble sulfide or hydrogen sulfide gas is added to sulfuric acid containing arsenic, and arsenic in sulfuric acid is sulfided. After insolubilizing as arsenic, a method of solid-liquid separation from sulfuric acid is generally performed. However, in the case of a mineral acid containing dilute arsenic with an arsenic concentration of 1000 ppm or less, arsenic sulfide crystal formation becomes extremely slow, and it takes a relatively long time of several days to remove arsenic in the mineral acid below a certain concentration. It is difficult to use. In addition, even after removing arsenic in the mineral acid to a certain concentration or less, there is a problem that arsenic remaining in the mineral acid reacts with the sulfide, and fine arsenic sulfide that hardly settles continues to precipitate.
[0003]
For this reason, the mineral acid waste liquid containing a dilute arsenic is the fact that the waste liquid treatment and discharge | emission were not carried out conventionally, but recycling. As a waste liquid treatment method, for example, a method is known in which the pH of a dilute arsenic-containing mineral acid waste liquid is adjusted to 7 or more to form arsenic sulfide, and then an iron salt compound is added to cause aggregation precipitation (for example, patents). Reference 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-277075
[Problems to be solved by the invention]
However, in order to increase the pH of the dilute arsenic-containing mineral acid waste solution to 7 or more, a large amount of alkaline substance is required, and the amount of the arsenic-containing precipitate is greatly increased by the addition of a flocculant such as iron salt. As a result, the final disposal cost of the arsenic-containing precipitate is increased.
[0006]
Accordingly, an object of the present invention is to provide a method for treating arsenic-containing sulfuric acid that can efficiently remove arsenic from sulfuric acid containing dilute arsenic having an arsenic concentration of 1000 ppm or less.
[0007]
[Means for Solving the Problems]
To achieve the above object, the processing method of the arsenic-containing sulfuric acid of the present invention is a method of treating arsenic-containing sulfuric acid arsenic concentration to remove arsenic from sulfuric acid containing dilute arsenic is 1000ppm or less, 2 g / L or more aqueous sodium and / or sodium hydrosulfide aqueous sulfide in said dilute arsenic containing sulfuric acid in the presence of added solid sulfide arsenic at a ratio of the weight ratio of sulfur relative to arsenic is added to be between 1 and 10 The arsenic is converted into solid arsenic sulfide, and then the solid arsenic sulfide is removed by solid-liquid separation means.
[0008]
Arsenic-containing sulfuric acid to be processed by the present invention is a sulfuric acid solution containing arsenic dilute concentration, specifically, the arsenic concentration is 1000ppm or less, less sulfuric acid solution in particular 500 ppm. The acid concentration of the sulfuric acid is not particularly limited. Moreover, even if it is a sulfuric acid containing impurities other than arsenic, it should just be that the impurities do not inhibit formation of arsenic sulfide.
[0009]
Examples of such arsenic-containing sulfuric acid include mine drainage, smelting factory process wastewater, chemical industry, electronic industry wastewater, and the like. In addition, in water treatment where arsenic is removed from water by adsorbing arsenic contained in water to the arsenic adsorbent, arsenic-containing sulfuric acid waste generated when sulfuric acid is regenerated with arsenic adsorbent, and sulfuric acid . Washing water generated when the treated arsenic adsorbent is washed is also a treatment target of the present invention.
[0010]
It is desirable that the arsenic-containing sulfuric acid to be treated has a pH of 4 or less, particularly 3 or less. If the pH of the arsenic-containing sulfuric acid exceeds 4, a suitable acid, usually the same type of sulfuric acid, should be used to adjust the pH.
[0011]
Upon removing arsenic from such arsenic containing sulfate,該Hiso containing sulfuric acid, the addition of aqueous sodium and / or sodium hydrosulfide aqueous sulfide arsenic-containing sulfuric acid in the presence of a non-solid sulfide-containing. In this way, in the presence of solid arsenic sulfide and / or sulfur, by bringing arsenic dissolved in sulfuric acid into contact with sodium sulfide or sodium hydrosulfide, precipitation of arsenic sulfide can be promoted, Subsequent solid-liquid separation is also facilitated. At this time, it is not preferable to use a solid sulfide such as copper sulfide because it does not contribute to crystal formation of arsenic sulfide but also dissolves itself to release copper ions.
[0012]
The solid sulfide arsenic is not shaped matter if solids, considering the solid-liquid separation in the subsequent stage, the average particle diameter is preferably not less than 0.1 mm. The method of adding the solid sulfide arsenic is to in powdered form may be added as it is, or may be hydrolyzed to be added in a slurry form. The addition amount of the solid sulfide arsenic is proportional to throughput of arsenic-containing sulfuric acid, relative to the arsenic content sulfuric acid treatment of 1L / hr, the solid sulfide arsenic is more than 1g, preferably 2g or more, particularly 4g or more Preferably there is.
[0013]
As the sodium sulfide and / or sodium hydrosulfide used as the sulfiding agent, commercially available sodium sulfide or sodium hydrosulfide can be used. The use of sodium sulfide as a sulfurizing agent and / or sodium hydrosulfide, and produce sulfide arsenic in reaction in sulfuric acid was precipitated on the surface of the solid sulphide arsenide which is previously added as seed crystals, subsequent It can be easily removed by the solid-liquid separator.
[0014]
The addition amount of the sulfurizing agent (sodium sulfide and / or sodium hydrosulfide) must be at least the sulfur equivalent required for the arsenic sulfide to be produced, but the reaction rate is higher if it is added slightly more than the equivalent. Become. However, since a large excess wasted with the addition, to set the amount of the sulfurizing agent so that the weight ratio of sulfur relative to arsenic is between 1 and 10.
[0015]
The contact time between the arsenic-containing sulfuric acid and the sulfurizing agent is 10 minutes or longer, preferably 15 minutes or longer. When the contact time is less than 10 minutes, the arsenic removal rate may be insufficient. The temperature of the arsenic-containing sulfuric acid when contacting with the sulfurizing agent is suitably in the range of 20 to 90 ° C, and particularly preferably in the range of 30 to 60 ° C. The higher the temperature, the faster the reaction rate and the higher the removal rate, so that the treatment can be completed in a short time. However, if the temperature is too high, a large amount of energy is required for heating, which is a problem in terms of cost. It may become.
[0016]
The solid-liquid contact device for contacting the arsenic-containing sulfuric acid and sulfiding agent in the presence of a solid sulfide arsenic, a known apparatus which has been conventionally used can be used. Solid sulfide arsenic may be formed a fixed bed or a fluidized bed by staying in the solid-liquid contact apparatus, and addition of the necessary amount of stock solution, the subsequent solid-liquid separation through the complete mixing solid-liquid contacting device You may make it isolate | separate with an apparatus.
[0017]
The produced arsenic sulfide crystals may be separated by adding a solid-liquid separation function to the solid-liquid contact device. However, since the crystals are small and the sedimentation property is poor, a solid-liquid separation device is placed after the solid-liquid contact device. It is desirable to provide and reliably remove with this solid-liquid separator. As the solid-liquid separation device, known physical solid-liquid separation devices including commonly used gravity sedimentation and filtration can be used.
[0018]
In this way, arsenic can be efficiently removed from the arsenic-containing sulfuric acid , but hydrogen sulfide gas is produced by the reaction of sodium sulfide or sodium hydrosulfide used as a sulfiding agent with sulfuric acid, and this hydrogen sulfide gas is treated. May be dissolved in sulfuric acid . When hydrogen sulfide gas into the process in the sulfuric acid is dissolved, or generate arsenic sulfide reacts with arsenic remaining in the sulfuric acid treatment, the decomposition to sometimes produce sulfur, after processing sulfate Inconvenience may occur when processing or reusing.
[0019]
Thus, if the dissolved hydrogen sulfide gas in the process sulfuric acid is a problem, it is necessary to remove hydrogen sulfide gas from the treatment in sulfuric acid. The removal treatment of hydrogen sulfide gas from the treated sulfuric acid can be performed by any one of aeration treatment, heat treatment, oxidation treatment and vacuum suction treatment, or a combination thereof.
[0020]
The aeration process may be a normal aeration process using a gas such as air or nitrogen, and can be performed using various conventionally used aeration devices. By performing this aeration process, hydrogen sulfide gas dissolved in this process sulfuric acid is removed from the entrained processing sulfate diffuser air or the like, or a sulfuric acid is oxidized by oxygen in air. What is necessary is just to set the time and the amount of aeration of this aeration process according to the amount of hydrogen sulfide dissolved in process sulfuric acid and liquid temperature.
[0021]
The heat treatment is to release the hydrogen sulfide gas from the treated sulfuric acid by holding the treated sulfuric acid at a temperature higher than the temperature of the solid-liquid contact treatment and reducing the solubility of the hydrogen sulfide gas. Can be set according to the amount of dissolved hydrogen sulfide gas in the treated sulfuric acid and the liquid temperature, but the heating temperature is usually preferably 50 ° C. or higher.
[0022]
In the oxidation treatment, hydrogen sulfide gas is removed from the treated sulfuric acid by adding an oxidizing agent such as oxygen or hydrogen peroxide to the treated sulfuric acid , and oxidizing the hydrogen sulfide gas in the treated sulfuric acid with an oxidizing agent to produce sulfuric acid. Is. What is necessary is just to set the usage-amount of an oxidizing agent according to the dissolved amount of the hydrogen sulfide gas in a process sulfuric acid .
[0023]
The vacuum suction process is to release hydrogen sulfide gas from the treated sulfuric acid by holding the treated sulfuric acid in a reduced pressure environment using a vacuum pump or the like and reducing the solubility of the hydrogen sulfide gas. The pressure and treatment time at this time can be set according to the dissolved amount of hydrogen sulfide gas in the treated sulfuric acid and the liquid temperature.
[0024]
Further, the arsenic concentration in the treated sulfuric acid from which arsenic has been removed by the method of the present invention is several ppm to several tens of ppm. This concentration does not satisfy the discharge standard for wastewater of 0.1 ppm. In order to discharge the treated sulfuric acid to the outside, it is necessary to perform a second treatment. As this second treatment, a known method such as adsorption using an arsenic adsorbent or coagulation precipitation can be used. By combining the method of the present invention and the second processing method, the arsenic load required for the second processing is greatly reduced from a few tenths to a few hundredths up to now. In addition to being able to reduce the scale, the amount of arsenic-containing precipitates is greatly reduced, and the disposal cost can be greatly reduced. Furthermore, arsenic sulfide produced by the method of the present invention and separated into solid and liquid has an advantage that it has high purity and easily leads to reuse.
[0025]
【Example】
Example 1及 beauty Comparative Example 1
4 g / L of As2S5 slurry (Example 1 ) and 20 g / L of CuS slurry (Comparative Example 1) were respectively added to 500 mL of 2N sulfuric acid having an arsenic (As5 +) concentration of 100 mg / L, and the mixture was heated to 50 ° C. and sulfided. It was made to react for 4 hours, adding sodium aqueous solution. The amount of sodium sulfide added was adjusted to 400 mg-S / L. Then, it separated into solid and liquid with the filter paper, and the residual As density | concentration in the sulfuric acid of a filtrate was measured. Table 1 summarizes each experimental condition and measurement result.
[0026]
Table 1
Example 1 Comparative Example 1
Additives As2S5 CuS
Additive concentration 4g / L 20g / L
1L / hr processing amount conversion addition amount 16g 80g
Arsenic removal rate 87.3% 0%
[0027]
Comparative Example 2
To 200 mL of 2N sulfuric acid having an arsenic (As5 +) concentration of 100 mg / L, an aqueous sodium hydrosulfide solution was added to room temperature to 214 mg-S / L. Subsequently, it separated into solid and liquid with the filter paper, and the residual As density | concentration in the sulfuric acid of a filtrate was measured. Table 2 shows experimental conditions and measurement results.
[0028]
Table 2
Additive None Additive concentration −
Reaction time 24 hours 1L / hr Addition amount in terms of throughput-
Sulfurizing agent addition amount 214mg-S / L
Reaction temperature Room temperature Arsenic removal rate 40.0%
[0029]
Examples 2 and 3
Arsenic sulfide slurry was added to 500 mL of 2N sulfuric acid having an arsenic (As5 +) concentration of 100 mg / L under the conditions shown in Table 3, and a sodium hydrosulfide aqueous solution was added dropwise at room temperature (Example 2 ) and 50 ° C. (Example 3 ). Reacted for hours. The amount of sodium hydrosulfide added was adjusted to 400 mg-S / L. Subsequently, it separated into solid and liquid with the filter paper, and the residual As density | concentration in the sulfuric acid of a filtrate was measured. Table 3 summarizes the experimental conditions and measurement results.
[0030]
Table 3
Example 2 Example 3
Additives Arsenic sulfide Arsenic sulfide additive concentration 4g / L 4g / L
Reaction time 4 hours 4 hours 1L / hr Treated amount addition 16g 16g
Reaction temperature Room temperature 50 ℃
Arsenic removal rate 65.4% 93.7%
[0031]
【The invention's effect】
As described above, according to the method for treating arsenic-containing sulfuric acid containing dilute arsenic having an arsenic concentration of 1000 ppm or less, further 500 ppm or less, arsenic dissolved in sulfuric acid can be efficiently removed. .
Claims (2)
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4889194A (en) * | 1972-02-29 | 1973-11-21 | ||
| JPS4896446A (en) * | 1972-03-25 | 1973-12-10 | ||
| JPS4929298A (en) * | 1972-07-15 | 1974-03-15 | ||
| JPS5732786A (en) * | 1980-08-02 | 1982-02-22 | Nippon Mining Co Ltd | Method and device for dearsenization |
| JPH11277075A (en) * | 1998-03-31 | 1999-10-12 | Dowa Mining Co Ltd | Method for removing/fixing arsenic existing in iron sulfate solution |
| JP2005041707A (en) * | 2003-07-23 | 2005-02-17 | Maezawa Ind Inc | Method of regenerating arsenic-containing mineral acid |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4889194A (en) * | 1972-02-29 | 1973-11-21 | ||
| JPS4896446A (en) * | 1972-03-25 | 1973-12-10 | ||
| JPS4929298A (en) * | 1972-07-15 | 1974-03-15 | ||
| JPS5732786A (en) * | 1980-08-02 | 1982-02-22 | Nippon Mining Co Ltd | Method and device for dearsenization |
| JPH11277075A (en) * | 1998-03-31 | 1999-10-12 | Dowa Mining Co Ltd | Method for removing/fixing arsenic existing in iron sulfate solution |
| JP2005041707A (en) * | 2003-07-23 | 2005-02-17 | Maezawa Ind Inc | Method of regenerating arsenic-containing mineral acid |
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