JP2014043611A - Method for recovering ruthenium - Google Patents
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本発明は、ルテニウムの回収方法に関し、詳細にはルテニウム含有酸性溶液から酸化蒸留によってルテニウムを回収する方法に関するものである。 The present invention relates to a method for recovering ruthenium, and more particularly to a method for recovering ruthenium from a ruthenium-containing acidic solution by oxidative distillation.
ルテニウムは自動車用触媒や電子機器の薄膜など各種産業分野で様々な用途に用いられている。ルテニウムは貴重な希少金属であるため、回収し、再利用することが求められている。 Ruthenium is used for various applications in various industrial fields such as automobile catalysts and electronic device thin films. Since ruthenium is a valuable rare metal, it must be recovered and reused.
使用済みスパッタリングターゲット材に代表されるルテニウム含有廃棄物には、ルテニウム以外にも白金、コバルト、クロム、鉄等の金属が含まれていることがあるため、ルテニウムを回収するにはルテニウムをこれら金属から分離することが必要となる。ルテニウムを他の金属と分離して回収する方法として、四酸化ルテニウムの揮発性を利用した酸化蒸留法が知られている。酸化蒸留法とは、ルテニウム含有廃棄物を酸に溶解させたルテニウム含有酸性溶液を反応槽に入れ、そこへ臭素酸ナトリウムなどの酸化剤を添加してルテニウムを四酸化ルテニウム（ＲｕＯ4）まで酸化して揮発させ、揮発した四酸化ルテニウムを酸・アルカリなどが入ったルテニウム吸収槽（回収槽）に導入して、他の金属と分離してルテニウムを回収する方法である。 Ruthenium-containing wastes such as used sputtering target materials may contain metals such as platinum, cobalt, chromium, and iron in addition to ruthenium. Need to be separated from As a method for separating and recovering ruthenium from other metals, an oxidative distillation method using the volatility of ruthenium tetroxide is known. Oxidation The oxidation distillation method, until the ruthenium-containing acidic solution dissolved in acid the ruthenium-containing waste is placed in a reaction vessel, wherein the addition to ruthenium tetroxide and ruthenium an oxidizing agent such as sodium bromate (RuO 4) The volatilized ruthenium tetroxide is introduced into a ruthenium absorption tank (recovery tank) containing an acid / alkali, and separated from other metals to recover ruthenium.
上記従来の酸化蒸留法によるルテニウム回収方法の問題点として、蒸留中に二酸化ルテニウム（ＲｕＯ2）の析出物が生じてルテニウムの収率が低下することや蒸留途中でルテニウム含有酸性溶液のｐＨが上昇して四酸化ルテニウムの酸化蒸留が進まなくなることが指摘されている。一般にルテニウム含有酸性溶液中のルテニウムは、二酸化ルテニウムを経て揮発性の四酸化ルテニウムに酸化される（ＲｕＯ2＋２Ｈ2Ｏ→ＲｕＯ4＋４Ｈ+＋４ｅ-）。四酸化ルテニウムは揮発性が高いため、気体状態でルテニウム吸収槽に導入されて回収されるが、反応槽内の酸化力が酸化剤の不足等によって低下すると、酸化反応が停止したり、反応槽に滞留した四酸化ルテニウムが二酸化ルテニウムに還元されたりするため、反応槽内の酸化剤溶液中の二酸化ルテニウムの濃度が上昇して酸化剤溶液中や反応槽内壁に二酸化ルテニウムの析出物（黒色物）が生成・付着するようになる。一度析出した二酸化ルテニウムの析出物は蒸留中に再溶解し難く、反応槽内に残留するため、ルテニウムの収率が低下する原因となっていた。 Problems with the above-described conventional ruthenium recovery method by oxidative distillation include that ruthenium dioxide (RuO 2 ) precipitates during distillation, resulting in a decrease in the yield of ruthenium and an increase in the pH of the ruthenium-containing acidic solution during the distillation. Thus, it has been pointed out that oxidative distillation of ruthenium tetroxide does not proceed. In general, ruthenium in a ruthenium-containing acidic solution is oxidized to volatile ruthenium tetroxide via ruthenium dioxide (RuO 2 + 2H 2 O → RuO 4 + 4H + + 4e − ). Since ruthenium tetroxide is highly volatile, it is introduced into the ruthenium absorption tank and recovered in the gaseous state. However, if the oxidizing power in the reaction tank decreases due to lack of oxidant, the oxidation reaction stops or the reaction tank Since the ruthenium tetroxide staying in the reactor is reduced to ruthenium dioxide, the concentration of ruthenium dioxide in the oxidant solution in the reaction vessel increases, and the ruthenium dioxide precipitate (black matter) in the oxidant solution and on the inner wall of the reaction vessel ) Will be generated and adhered. The precipitate of ruthenium dioxide once precipitated is difficult to redissolve during distillation and remains in the reaction tank, causing a decrease in the ruthenium yield.
また、蒸留が進むとルテニウム含有溶液中の酸との反応によって酸化剤が分解されて酸が消費され、それに伴ってｐＨが高くなるが、酸化剤が機能しルテニウムを四酸化ルテニウムに変換できる最適ｐＨ領域を超えると、酸化蒸留が進まないという問題があった。 Also, as the distillation proceeds, the oxidant is decomposed by reaction with the acid in the ruthenium-containing solution and the acid is consumed, and the pH increases accordingly, but the oxidant functions and can convert ruthenium to ruthenium tetroxide. When the pH range was exceeded, there was a problem that oxidative distillation did not proceed.
このような問題を解決する技術として例えば特許文献１には、酸化剤として臭素酸ナトリウム（ＮａＢｒＯ3）を用い、ルテニウム含有酸性溶液のｐＨを０．５〜２．５に調整し、ルテニウムを四酸化ルテニウムに変換して酸化蒸留し、臭素酸ナトリウムの添加量がルテニウムから四酸化ルテニウムの酸化に必要な１当量に加え、臭素酸ナトリウム濃度が８０ｇ／Ｌ以上となるように過剰に加えることによって、白金族を含む溶液からルテニウムを分離回収する方法が開示されている。 As a technique for solving such a problem, for example, in Patent Document 1, sodium bromate (NaBrO 3 ) is used as an oxidizing agent, the pH of a ruthenium-containing acidic solution is adjusted to 0.5 to 2.5, and ruthenium is converted into four. By converting to ruthenium oxide and oxidatively distilling, adding sodium bromate in an amount equivalent to 1 equivalent required for oxidation of ruthenium tetroxide from ruthenium, and adding excessively so that the sodium bromate concentration is 80 g / L or more A method for separating and recovering ruthenium from a solution containing a platinum group is disclosed.
上記特許文献１では、酸化剤の分解によってｐＨが上昇する前に、ルテニウムに対して過剰量の酸化剤である臭素酸ナトリウムを一度に加えて酸化反応を速やかに終了させている。 In Patent Document 1, before the pH rises due to decomposition of the oxidizing agent, an excessive amount of sodium bromate, which is an oxidizing agent with respect to ruthenium, is added at once to quickly terminate the oxidation reaction.
しかしながら、上記特許文献１のようにルテニウム含有酸性液中に過剰量の酸化剤を一度に添加する方法は、次のような問題がある。 However, the method of adding an excessive amount of oxidizing agent at once to the ruthenium-containing acidic liquid as in Patent Document 1 has the following problems.
第一に、高濃度のルテニウム含有溶液を回収対象材料とした場合、酸化剤の添加量をルテニウム濃度に応じて増やす必要があるが、酸化剤の溶解度との関係で上限が存在するため、二酸化ルテニウムの析出やｐＨ上昇を抑止する根本的な解決法でない。 First, when a high-concentration ruthenium-containing solution is used as the material to be recovered, it is necessary to increase the amount of oxidant added according to the ruthenium concentration, but there is an upper limit in relation to the solubility of the oxidant. It is not a fundamental solution to suppress ruthenium precipitation and pH increase.
第二に、反応槽内のルテニウムが一度に四酸化ルテニウムまで変換され、四酸化ルテニウムが飽和溶解度を超えてルテニウム含有酸性液から分相して反応槽の底部に溜まるため、揮発が困難になる。第三に、一度に多量の四酸化ルテニウムが揮発すると不純物を含んだミストが回収槽まで運ばれてしまい、回収したルテニウムの純度が低下するだけでなく、吸収設備の大型化も必要となる。 Second, ruthenium in the reaction tank is converted to ruthenium tetroxide at a time, and ruthenium tetroxide exceeds the saturation solubility and separates from the ruthenium-containing acidic liquid and accumulates at the bottom of the reaction tank, making volatilization difficult. . Third, if a large amount of ruthenium tetroxide volatilizes at a time, the mist containing impurities is transported to the recovery tank, which not only lowers the purity of the recovered ruthenium, but also requires a larger absorption facility.
本発明は上記のような事情に着目してなされたものであって、その目的は、酸化蒸留法によるルテニウムの回収技術に伴う上記問題点である蒸留時の二酸化ルテニウムの析出や、一度に大量の四酸化ルテニウムが生成することに伴う四酸化ルテニウムの分相化、回収したルテニウムの純度低下等の問題を解消して、高純度のルテニウムを高収率で回収する方法を提供することにある。 The present invention has been made paying attention to the above-mentioned circumstances, and its purpose is to precipitate ruthenium dioxide during distillation, which is the above-mentioned problem associated with the ruthenium recovery technique by oxidative distillation, and to produce a large amount at a time. It is intended to provide a method for recovering high-purity ruthenium in a high yield by solving the problems such as phase separation of ruthenium tetroxide associated with the formation of ruthenium tetroxide and reduction in purity of the recovered ruthenium. .
上記課題を解決し得た本発明のルテニウム回収方法は、ルテニウム含有酸性溶液中のルテニウムを酸化反応によって揮発性の四酸化ルテニウムに酸化し、蒸留してルテニウムを回収する方法において、前記酸化反応は、酸化反応に必要な当量以上の酸化剤を含有する酸化剤溶液中に、前記ルテニウム含有酸性溶液を添加して行うことに要旨を有する。 The ruthenium recovery method of the present invention that has solved the above problems is a method in which ruthenium in a ruthenium-containing acidic solution is oxidized to volatile ruthenium tetroxide by an oxidation reaction, and the ruthenium is recovered by distillation. The present invention is summarized in that the ruthenium-containing acidic solution is added to an oxidant solution containing an oxidant of an equivalent amount or more necessary for the oxidation reaction.
また前記酸化反応は、前記酸化剤溶液に前記ルテニウム含有酸性溶液を添加した反応液の中で四酸化ルテニウムが前記反応液と分相しないように、前記反応液中の四酸化ルテニウム濃度を調整しながら行うものであることも好ましい実施態様である。 In the oxidation reaction, the ruthenium tetroxide concentration in the reaction solution is adjusted so that ruthenium tetroxide does not phase-divide with the reaction solution in the reaction solution in which the ruthenium-containing acidic solution is added to the oxidant solution. However, it is also a preferred embodiment.
本発明の方法によれば、酸化蒸留法によるルテニウムの回収方法において、従来のように酸化剤溶液をルテニウム含有酸性溶液中に添加して揮発性の四酸化ルテニウムを蒸留してルテニウムを回収するのではなく、ルテニウム含有酸性溶液を酸化反応に必要な当量以上の酸化剤を含有する酸化剤溶液中に添加しているため、酸化剤の追加投入を行わなくても、常にルテニウムに対して、酸化剤が不足しない反応状態を維持することができる。その結果、酸化力低下による酸化剤溶液中への二酸化ルテニウムの析出、および未反応のルテニウム残留が抑制されるほか、酸化剤の使用量を従来の方法に比べて低減することができる。 According to the method of the present invention, in the method for recovering ruthenium by the oxidative distillation method, the oxidant solution is added to the ruthenium-containing acidic solution and the volatile ruthenium tetroxide is distilled to recover ruthenium as in the prior art. Instead, the ruthenium-containing acidic solution is added to the oxidant solution containing an oxidant in an amount equivalent to or more than that required for the oxidation reaction. The reaction state in which the agent is not insufficient can be maintained. As a result, precipitation of ruthenium dioxide in the oxidant solution due to a reduction in oxidizing power and unreacted ruthenium residue are suppressed, and the amount of oxidant used can be reduced as compared with conventional methods.
また本発明の方法によれば、好ましくは、四酸化ルテニウムがルテニウム含有酸性溶液を添加した酸化剤溶液（以下、反応液ということがある）と分相しないように、反応液中の四酸化ルテニウム濃度を調整しながら酸化反応を行なっているため、反応液内に滞留した四酸化ルテニウムが二酸化ルテニウムに還元されて反応槽内に析出し、ルテニウムの回収率が低下することを防止できる。 In addition, according to the method of the present invention, preferably, ruthenium tetroxide in the reaction solution is not separated from the oxidant solution (hereinafter sometimes referred to as reaction solution) to which ruthenium-containing acidic solution is added. Since the oxidation reaction is carried out while adjusting the concentration, it is possible to prevent ruthenium tetroxide retained in the reaction solution from being reduced to ruthenium dioxide and precipitated in the reaction vessel, thereby reducing the ruthenium recovery rate.
また、反応液中で四酸化ルテニウムが滞留し、分相しない速度でルテニウム含有酸性溶液を定量的に酸化剤溶液に添加することにより、一度に揮発する四酸化ルテニウムの量を制御できるため、不純物を含んだミストの発生を抑制でき、ミストトラップなしに純度を確保できる。更に上記のように添加することにより、四酸化ルテニウムの揮発速度を制御できるため、四酸化ルテニウムの回収(吸収)設備を小型化できる。 In addition, ruthenium tetroxide stays in the reaction solution, and the amount of ruthenium tetroxide volatilized at a time can be controlled by quantitatively adding the ruthenium-containing acidic solution to the oxidant solution at a rate that does not cause phase separation. The generation of mist containing can be suppressed, and purity can be secured without a mist trap. Furthermore, by adding as described above, the volatilization rate of ruthenium tetroxide can be controlled, so that the ruthenium tetroxide recovery (absorption) facility can be downsized.
その結果、本発明によれば、ルテニウムの回収率が向上し、高純度（おおむね９９．９％以上）のルテニウムを高収率（おおむね９９％以上）で回収できるという効果が得られる。 As a result, according to the present invention, it is possible to improve the recovery rate of ruthenium and to obtain an effect that high-purity (approximately 99.9% or more) ruthenium can be recovered in a high yield (approximately 99% or more).
前述した特許文献１との関係において本発明の最も大きな特徴部分は、ルテニウム含有酸性溶液中のルテニウムを酸化反応によって揮発性の四酸化ルテニウムに酸化するに当たり、酸化剤溶液中に、ルテニウム含有酸性溶液を添加して酸化反応を行なうところにある。 In relation to the above-mentioned Patent Document 1, the most important feature of the present invention is that when ruthenium in a ruthenium-containing acidic solution is oxidized to volatile ruthenium tetroxide by an oxidation reaction, the ruthenium-containing acidic solution is included in the oxidizing agent solution. In the oxidation reaction.
以下、本発明に到達した経緯について説明する。 Hereinafter, the process of reaching the present invention will be described.
本発明者らは、上記問題を解消し、高純度のルテニウムを高収率で、しかも通常用いられる装置で回収する方法を提供するため、ルテニウムと酸化剤の反応に留意して検討を行なった。 In order to solve the above problems and to provide a method for recovering high-purity ruthenium in a high yield and using a commonly used apparatus, the present inventors have studied paying attention to the reaction between ruthenium and an oxidizing agent. .
上述したようにルテニウムと酸化剤の反応は非常に早く、両者が混合された時点で酸化反応が直ちに進行する。そのため、両者の混合時点でのルテニウムと酸化剤の量が酸化反応に大きく影響することになり、酸化剤が不足していれば、前述したような反応性の低下やｐＨ変動による二酸化ルテニウムの析出が起るようになる。 As described above, the reaction between ruthenium and the oxidizing agent is very fast, and when both are mixed, the oxidation reaction proceeds immediately. Therefore, the amount of ruthenium and oxidant at the time of mixing of both greatly affects the oxidation reaction. If the oxidant is insufficient, the precipitation of ruthenium dioxide due to a decrease in reactivity or pH fluctuation as described above. Comes to happen.
これに対し、本発明では、酸化剤溶液にルテニウム含有酸性溶液を添加し、酸化反応時、ルテニウムに対して常に、酸化剤が不足しない反応状態を維持している。本発明の方法によれば、上記特許文献１で懸念された二酸化ルテニウムの析出は起こらず、添加したルテニウムは全て四酸化ルテニウムまで酸化することができる。 On the other hand, in the present invention, a ruthenium-containing acidic solution is added to the oxidant solution, and during the oxidation reaction, a reaction state in which the oxidant is not insufficient is always maintained with respect to ruthenium. According to the method of the present invention, precipitation of ruthenium dioxide, which has been a concern in Patent Document 1, does not occur, and all the added ruthenium can be oxidized to ruthenium tetroxide.
さらに四酸化ルテニウムの分相が生じないようにルテニウム含有酸性溶液の添加量を調整し、反応液中の四酸化ルテニウム濃度が過剰にならないようにするため、四酸化ルテニウムは反応液中に滞留せず、したがって分相も起こらない。 Furthermore, the amount of ruthenium-containing acidic solution added is adjusted so that ruthenium tetroxide phase separation does not occur, so that the ruthenium tetroxide concentration in the reaction solution does not become excessive, so that ruthenium tetroxide stays in the reaction solution. Therefore, no phase separation occurs.
以下、本発明について説明する。 The present invention will be described below.
本発明において、ルテニウム含有酸性溶液とは、ルテニウム含有廃棄物（例えば使用済みスパッタリングターゲット材など）を適当な酸で溶解させた溶液である。用いる酸はルテニウムを溶解できれば特に限定されず、例えば塩酸、硝酸、王水などが挙げられる。 In the present invention, the ruthenium-containing acidic solution is a solution in which ruthenium-containing waste (for example, a used sputtering target material) is dissolved with an appropriate acid. The acid to be used is not particularly limited as long as it can dissolve ruthenium, and examples thereof include hydrochloric acid, nitric acid, aqua regia and the like.
本発明のルテニウム含有酸性溶液には、ルテニウム以外の金属（不純物金属）が含まれていてもよく、不純物金属としては、例えばＰｔ、Ｐｄなどの白金族、Ｃｏ、Ｃｒなどの重金属が挙げられる。本発明では、四酸化ルテニウムの揮発性を利用した蒸留方法を採用しているため、ルテニウム含有酸性溶液に白金族元素や重金属元素などの不純物金属が含まれていても、ルテニウムを容易に分離・回収できる。 The ruthenium-containing acidic solution of the present invention may contain a metal (impurity metal) other than ruthenium. Examples of the impurity metal include platinum groups such as Pt and Pd and heavy metals such as Co and Cr. In the present invention, since a distillation method utilizing the volatility of ruthenium tetroxide is adopted, ruthenium can be easily separated even if the ruthenium-containing acidic solution contains an impurity metal such as a platinum group element or a heavy metal element. Can be recovered.
また本発明において、酸化剤溶液とは、酸化剤を水、或いは酸化剤の最適ｐＨに調整した水（例えばｐＨ０．５〜２．５程度に調整した水）に溶解させたものである。酸化剤としては、ルテニウムを四酸化ルテニウムまで酸化できると共に、水またはｐＨを調整した水に対して易溶解性のものであれば特に限定されない。このような性質を有する酸化剤としては、例えば過塩素酸、塩素酸、臭素酸、過マンガン酸などのアルカリ金属塩が挙げられる。これらの中でも臭素酸ナトリウムが好適である。 In the present invention, the oxidizing agent solution is a solution in which an oxidizing agent is dissolved in water or water adjusted to the optimum pH of the oxidizing agent (for example, water adjusted to about pH 0.5 to 2.5). The oxidizing agent is not particularly limited as long as it can oxidize ruthenium to ruthenium tetroxide and is easily soluble in water or water adjusted in pH. Examples of the oxidizing agent having such properties include alkali metal salts such as perchloric acid, chloric acid, bromic acid, and permanganic acid. Of these, sodium bromate is preferred.
さらに本発明において、反応液とは、上記ルテニウム含有酸性溶液が上記酸化剤溶液に添加された溶液をいう。なお、本発明ではルテニウム含有酸性溶液を添加する前の酸化剤溶液と、ルテニウム含有酸性溶液を添加した後の酸化剤溶液（反応液）を特に区別する必要がない場合は、両者を含む意味で酸化剤溶液ということがある。 Furthermore, in the present invention, the reaction solution refers to a solution in which the ruthenium-containing acidic solution is added to the oxidant solution. In the present invention, when it is not necessary to particularly distinguish the oxidant solution before adding the ruthenium-containing acidic solution and the oxidant solution (reaction solution) after adding the ruthenium-containing acidic solution, the meaning includes both. Sometimes referred to as an oxidizer solution.
本発明の方法を実施するにあたっては、酸化剤溶液中の酸化剤量は酸化反応時、ルテニウムに対して常に、酸化剤が不足しない反応状態が維持されていればよい。具体的には酸化反応に必要な当量以上であるが、ルテニウム含有酸性溶液による酸化剤の分解や反応速度向上の観点からは酸化剤量は多い程望ましく、ルテニウム含有酸性溶液中のルテニウム総量に対して好ましくは１当量を超える量、より好ましくは１．５当量以上である。一方、薬品使用量低減の観点から、酸化剤量は添加するルテニウム総量に対して４当量以下が好ましく、より好ましくは２当量以下である。 In carrying out the method of the present invention, the amount of the oxidant in the oxidant solution may be maintained in a reaction state in which the oxidant is not insufficient with respect to ruthenium during the oxidation reaction. Specifically, it is more than the equivalent amount required for the oxidation reaction, but from the viewpoint of decomposition of the oxidant by the ruthenium-containing acidic solution and improvement of the reaction rate, it is desirable that the amount of the oxidant is larger. The amount is preferably more than 1 equivalent, more preferably 1.5 equivalents or more. On the other hand, from the viewpoint of reducing the amount of chemicals used, the amount of oxidizing agent is preferably 4 equivalents or less, more preferably 2 equivalents or less, based on the total amount of ruthenium added.
また酸化剤溶液に添加する前のルテニウム含有酸性溶液中のルテニウム濃度も特に限定されない。ルテニウム含有酸性溶液中のルテニウム濃度が高い場合であっても、酸化剤量やルテニウム濃度、反応温度などの反応条件を考慮してルテニウム含有酸性溶液の添加量を調整すれば、上記諸問題を解決して高純度のルテニウムを高収率で回収することができる。またルテニウム濃度を高くすることによって処理するルテニウム含有酸性溶液の総液量を低減でき、蒸留装置の小型化や処理時間の短縮を図ることができる。ルテニウム含有酸性溶液中のルテニウム濃度は、好ましくは１０ｇ／Ｌ以上、より好ましくは４０ｇ／Ｌ以上としてもよい。またルテニウム濃度の上限は好ましくは２００ｇ／Ｌ以下である。 Further, the ruthenium concentration in the ruthenium-containing acidic solution before being added to the oxidant solution is not particularly limited. Even if the ruthenium-containing acidic solution has a high ruthenium concentration, the above problems can be solved by adjusting the addition amount of the ruthenium-containing acidic solution in consideration of the reaction conditions such as the amount of oxidizing agent, ruthenium concentration, reaction temperature Thus, high-purity ruthenium can be recovered with a high yield. Further, by increasing the ruthenium concentration, the total amount of the ruthenium-containing acidic solution to be treated can be reduced, and the distillation apparatus can be miniaturized and the treatment time can be shortened. The ruthenium concentration in the ruthenium-containing acidic solution is preferably 10 g / L or more, more preferably 40 g / L or more. The upper limit of the ruthenium concentration is preferably 200 g / L or less.
本発明の方法を実施する際の反応開始時、および反応中の酸化剤溶液の温度は特に限定されず、室温でもよいが、温度を高くすると、ルテニウムと酸化剤との反応速度が向上して短時間で四酸化ルテニウムに酸化できる。また反応温度を高くすることで四酸化ルテニウムの反応液に対する溶解度が上がるため、分相しにくくなる。したがって酸化剤溶液の温度は好ましくは４０℃以上、より好ましくは６０℃以上である。一方、酸化剤溶液の温度が高くなり過ぎると液体（たとえば水分）の蒸発量が多くなり、ルテニウム吸収槽の液量が増加して、吸収槽中の液からルテニウムを還元等により回収する際の回収率低下につながる可能性があるため、好ましくは９５℃以下、より好ましくは８０℃以下である。 The temperature of the oxidant solution during the start of the reaction when the method of the present invention is performed and during the reaction is not particularly limited, and may be room temperature. However, when the temperature is increased, the reaction rate between ruthenium and the oxidant is improved. It can be oxidized to ruthenium tetroxide in a short time. Moreover, since the solubility with respect to the reaction liquid of ruthenium tetroxide will raise by raising reaction temperature, it will become difficult to phase-separate. Therefore, the temperature of the oxidant solution is preferably 40 ° C. or higher, more preferably 60 ° C. or higher. On the other hand, if the temperature of the oxidizer solution becomes too high, the amount of evaporation of liquid (for example, moisture) increases, the amount of liquid in the ruthenium absorption tank increases, and when ruthenium is recovered from the liquid in the absorption tank by reduction or the like. Since it may lead to a reduction in recovery, it is preferably 95 ° C. or lower, more preferably 80 ° C. or lower.
また本発明の方法を実施する際の反応開始時、および反応中の酸化剤溶液のｐＨは、酸化剤の最適ｐＨ（反応時のｐＨが酸化剤として機能するのに適したｐＨ）に維持されていることが必要であるため、ルテニウム含有酸性溶液の添加に先立って、予め、或いは反応時に酸化剤溶液のｐＨを酸化剤の最適ｐＨに調節しておくことが好ましい。 In addition, the pH of the oxidant solution during the start of the reaction when the method of the present invention is carried out and during the reaction is maintained at the optimum pH of the oxidant (the pH during the reaction is suitable for functioning as an oxidant). Therefore, prior to the addition of the ruthenium-containing acidic solution, it is preferable to adjust the pH of the oxidant solution to the optimum pH of the oxidant in advance or during the reaction.
酸化剤溶液のｐＨ調整方法は特に限定されず、各種公知の方法を採用できる。例えば酸化剤溶液に酸などを添加してｐＨを調整してもよいし、或いは酸化剤溶液の調製に際して予めｐＨを調整した溶媒に酸化剤を溶解させて酸化剤溶液のｐＨを調整してもよい。例えば、臭素酸ナトリウムの場合、酸化剤として働く適正ｐＨ範囲はおおむね０．５〜２．５である。 The pH adjustment method of the oxidizing agent solution is not particularly limited, and various known methods can be employed. For example, the pH may be adjusted by adding an acid or the like to the oxidant solution, or the pH of the oxidant solution may be adjusted by dissolving the oxidant in a solvent whose pH has been adjusted in advance when preparing the oxidant solution. Good. For example, in the case of sodium bromate, the proper pH range that acts as an oxidizing agent is approximately 0.5 to 2.5.
また添加したルテニウム含有酸性溶液のｐＨによって酸化剤溶液のｐＨが変動するのを抑制するために、ルテニウム含有酸性溶液のｐＨも上記酸化剤溶液の場合と同様、最適なｐＨに調整しておくことが好ましい。例えば、酸化剤が臭素酸ナトリウムの場合、酸化剤として働く適正ｐＨ範囲（０．５〜２．５）となるようにルテニウム含有酸性溶液のｐＨを調整（０．５〜２．５）することが望ましい。 In addition, in order to prevent the pH of the oxidant solution from fluctuating due to the pH of the added ruthenium-containing acidic solution, the pH of the ruthenium-containing acidic solution should be adjusted to an optimum pH as in the case of the oxidant solution. Is preferred. For example, when the oxidizing agent is sodium bromate, the pH of the ruthenium-containing acidic solution is adjusted (0.5 to 2.5) so that the proper pH range (0.5 to 2.5) that acts as the oxidizing agent is obtained. Is desirable.
上記したようにルテニウムは酸化剤によって二酸化ルテニウムを経て揮発性の四酸化ルテニウムに酸化される（ＲｕＯ2＋２Ｈ2Ｏ→ＲｕＯ4＋４Ｈ+＋４ｅ-）。一方、反応液中のルテニウム以外の金属は揮発しないため、反応液中に残存する。そのため酸化蒸留方法によって、ルテニウムを他の金属から分離して高純度で回収できる。 As described above, ruthenium is oxidized to volatile ruthenium tetroxide through ruthenium dioxide by an oxidizing agent (RuO 2 + 2H 2 O → RuO 4 + 4H + + 4e − ). On the other hand, since metals other than ruthenium in the reaction solution do not volatilize, they remain in the reaction solution. Therefore, ruthenium can be separated from other metals and recovered with high purity by oxidative distillation.
また上記酸化反応は、反応液中の四酸化ルテニウム濃度が飽和溶解度を超えないような条件で行うことが好ましい。このような条件で酸化反応を行うことによって、反応液中の四酸化ルテニウムの滞留を抑制でき、四酸化ルテニウムの分相や二酸化ルテニウムへの還元を防止できる。 The oxidation reaction is preferably performed under conditions such that the ruthenium tetroxide concentration in the reaction solution does not exceed the saturation solubility. By performing the oxidation reaction under such conditions, the retention of ruthenium tetroxide in the reaction solution can be suppressed, and the phase separation of ruthenium tetroxide and ruthenium dioxide can be prevented.
四酸化ルテニウム濃度が反応液中で飽和溶解度を超えない条件としては以下のような条件が例示されるが、これに限定されない。 Examples of the conditions under which the ruthenium tetroxide concentration does not exceed the saturation solubility in the reaction solution include the following conditions, but are not limited thereto.
酸化反応は、四酸化ルテニウムが反応液と分相しないように、反応液中の四酸化ルテニウム濃度を調整しながら行うことが望ましい。例えば、四酸化ルテニウムは飽和溶解度を超えると四酸化ルテニウムが反応槽の底部にオレンジ色の相となって滞留するため、目視により着色の有無を確認しながら、酸化反応を行えばよい。その際、飽和溶解度を超えない条件としては、例えば、四酸化ルテニウムに酸化される反応速度と四酸化ルテニウムが揮発してルテニウム吸収槽へ移動する速度を考慮すればよい。四酸化ルテニウムに酸化される反応速度が、四酸化ルテニウムがルテニウム吸収槽へ移動する速度を上回ると、反応液中の四酸化ルテニウム濃度が高くなる。このような状態を抑制するために、反応槽内に空気を供給して、四酸化ルテニウムがルテニウム吸収槽に移動する速度の向上を図ることが好ましい。供給された空気によって四酸化ルテニウムがルテニウム吸収槽に移動し易くなり、四酸化ルテニウムの滞留を抑制できる。四酸化ルテニウムは空気よりも比重が重いため、空気を反応槽下部（反応液中、もしくは酸化剤溶液近傍）に供給すると四酸化ルテニウムの滞留抑制に効果的である。更に、反応槽内の気体を吸引して反応槽内を減圧状態にすると四酸化ルテニウムがルテニウム吸収槽に移動する速度を向上できる。 The oxidation reaction is desirably performed while adjusting the ruthenium tetroxide concentration in the reaction solution so that ruthenium tetroxide does not phase-divide with the reaction solution. For example, when ruthenium tetroxide exceeds the saturation solubility, ruthenium tetroxide stays in an orange phase at the bottom of the reaction tank, so that the oxidation reaction may be carried out while visually confirming the presence or absence of coloring. In this case, as conditions for not exceeding saturation solubility, for example, the reaction rate of oxidation to ruthenium tetroxide and the rate at which ruthenium tetroxide volatilizes and moves to the ruthenium absorption tank may be considered. When the reaction rate of oxidation to ruthenium tetroxide exceeds the rate at which ruthenium tetroxide moves to the ruthenium absorption tank, the ruthenium tetroxide concentration in the reaction solution increases. In order to suppress such a state, it is preferable to improve the speed at which ruthenium tetroxide moves to the ruthenium absorption tank by supplying air into the reaction tank. The supplied air makes it easier for ruthenium tetroxide to move to the ruthenium absorption tank, and the retention of ruthenium tetroxide can be suppressed. Since ruthenium tetroxide has a higher specific gravity than air, supplying air to the lower part of the reaction tank (in the reaction solution or in the vicinity of the oxidant solution) is effective in suppressing the retention of ruthenium tetroxide. Furthermore, when the gas in the reaction tank is sucked to reduce the pressure in the reaction tank, the speed at which ruthenium tetroxide moves to the ruthenium absorption tank can be improved.
また反応条件などを考慮してルテニウム含有酸性溶液の添加量を調整、すなわち、ルテニウム含有酸性溶液の添加速度をコントロールすることも好ましい。 It is also preferable to adjust the addition amount of the ruthenium-containing acidic solution in consideration of the reaction conditions, that is, to control the addition rate of the ruthenium-containing acidic solution.
ルテニウム含有酸性溶液の好ましい添加速度は、酸化剤溶液に対する四酸化ルテニウムの飽和溶解度よりも低く保持できる添加速度である。 A preferred addition rate of the ruthenium-containing acidic solution is an addition rate that can be kept lower than the saturation solubility of ruthenium tetroxide in the oxidant solution.
また、ルテニウム含有酸性溶液の添加速度は、例えば四酸化ルテニウムの飽和溶解度を超えないようにルテニウム含有酸性溶液を定量的に添加することにより、一度に揮発する四酸化ルテニウムの量を制御できるため、不純物を含んだミストの発生を抑制でき、ミストトラップなしに純度を確保できる。更に上記のように添加することにより、一定速度で四酸化ルテニウムが揮発するため、ガス発生量にピークが存在せず、四酸化ルテニウムの回収(吸収)設備を小型化できる。 Moreover, the addition rate of the ruthenium-containing acidic solution can control the amount of ruthenium tetroxide volatilized at a time by quantitatively adding the ruthenium-containing acidic solution so as not to exceed the saturation solubility of ruthenium tetroxide, for example. Generation of mist containing impurities can be suppressed, and purity can be secured without a mist trap. Further, by adding as described above, ruthenium tetroxide is volatilized at a constant rate, so that there is no peak in the amount of gas generated, and the ruthenium tetroxide recovery (absorption) facility can be downsized.
以下、蒸留方法について説明する。 Hereinafter, the distillation method will be described.
本発明の好ましいルテニウム回収方法について図１の蒸留装置を参照しながら具体的に説明するが、図１に限定されるものではなく、前後記の記載に基づいて適当に変更を加えて実施することも可能であり、それらはいずれも本発明の技術的範囲に包含される。 The preferred method for recovering ruthenium of the present invention will be described in detail with reference to the distillation apparatus of FIG. 1, but is not limited to FIG. 1 and should be carried out with appropriate modifications based on the descriptions given before and after. Are all possible and are within the scope of the present invention.
図１はルテニウム含有酸性溶液からルテニウムを分離回収する蒸留装置の構成例である。蒸留装置は、ルテニウムを酸化反応させる反応槽１と、揮発性の四酸化ルテニウムを回収するルテニウム吸収槽６、有害ガスを回収するガス吸収槽７が順次接続された構成となっている。図１ではルテニウム吸収槽６は２つの吸収槽（６ａ〜６ｂ）からなるが、吸収槽の数は限定されない。またガス吸収槽７は１段であるが、必要に応じて任意の段数設けることができる。
FIG. 1 is a configuration example of a distillation apparatus for separating and recovering ruthenium from a ruthenium-containing acidic solution. The distillation apparatus has a configuration in which a reaction tank 1 for oxidizing ruthenium, a
まず、反応槽１に酸化剤溶液（例えば臭素酸ナトリウム）を所定量充填する。続いてヒーター２によって酸化剤溶液を所定の温度に加熱をする（図示例では温度計８で温度を測定している）。 First, the reaction tank 1 is filled with a predetermined amount of an oxidizing agent solution (for example, sodium bromate). Subsequently, the oxidant solution is heated to a predetermined temperature by the heater 2 (in the illustrated example, the temperature is measured by the thermometer 8).
次に、ルテニウム含有酸性溶液は定量ポンプなどで一定量を連続的、あるいは所定量を断続的（バッチ式）に供給路３から反応槽１内に添加する。 Next, the ruthenium-containing acidic solution is added into the reaction tank 1 from the supply path 3 continuously or in a predetermined amount intermittently (batch type) with a metering pump or the like.
反応槽１内で供給したルテニウム含有酸性溶液中のルテニウムは酸化剤による酸化反応によって揮発性の四酸化ルテニウムに酸化されて蒸留ガスとしてルテニウム吸収槽６に導入される。各ルテニウム吸収槽６の中には吸収液（好ましくは塩酸（ＨＣｌ））が入っており、蒸留ガスはルテニウム吸収槽（６ａ〜６ｂ）に導入され、吸収される。ルテニウム吸収後の液は別途取り出されてルテニウムが回収される。
Ruthenium in the ruthenium-containing acidic solution supplied in the reaction tank 1 is oxidized into volatile ruthenium tetroxide by an oxidation reaction with an oxidizing agent and introduced into the
また反応槽１内で副生した有毒ガス（臭素ガス、塩素ガス、窒素酸化物ガスなど）は、吸収液（好ましくは水酸化ナトリウム溶液（ＮａＯＨ））が入っているガス吸収槽７に導入され、回収される。 In addition, toxic gases (bromine gas, chlorine gas, nitrogen oxide gas, etc.) by-produced in the reaction tank 1 are introduced into a gas absorption tank 7 containing an absorption liquid (preferably sodium hydroxide solution (NaOH)). To be recovered.
上記蒸留方法によって、ルテニウム含有酸性溶液に含まれる不純物金属は反応槽１でルテニウムと分離され、反応槽１の反応液中に残存するため、ルテニウム吸収槽６の吸収液からは高純度のルテニウムを回収できる。ルテニウム吸収槽６の塩化ルテニウム酸溶液は公知の方法によってルテニウムとして回収することができる。例えばギ酸などの還元剤を塩化ルテニウム酸溶液に加えて還元することによってルテニウムを回収できる。
By the distillation method, the impurity metal contained in the ruthenium-containing acidic solution is separated from ruthenium in the reaction tank 1 and remains in the reaction liquid in the reaction tank 1, so that high-purity ruthenium is obtained from the absorption liquid in the
蒸留に際しては、人体に有害な四酸化ルテニウムが系外に流出しないように吸引ポンプなどの減圧ポンプ４などを用いて蒸留系内の気体を吸引して減圧下で酸化蒸留を行うことが好ましい。また反応槽１内の四酸化ルテニウムを速やかにルテニウム吸収槽６に導くために、空気などの気体を供給してもよい。図示例では、減圧ポンプ４によって蒸留装置内を減圧にすると共に、空気供給路５から反応槽１内に空気を供給している。
In the distillation, it is preferable to perform oxidative distillation under reduced pressure by sucking the gas in the distillation system using a vacuum pump 4 such as a suction pump so that ruthenium tetroxide harmful to the human body does not flow out of the system. Further, a gas such as air may be supplied in order to quickly guide ruthenium tetroxide in the reaction tank 1 to the
また添加したルテニウム含有酸性溶液は、反応槽１内で速やかに酸化剤溶液中に分散させることが反応速度向上の観点から好ましいため、反応槽１内には攪拌手段を設けることが好ましく、攪拌手段としては例えば供給した空気によるバブリングやスクリューなどによる機械的な攪拌が挙げられる。図１ではヒーター２が攪拌機能を有しており、反応槽１内に攪拌子を入れて攪拌を行っている。 Moreover, since it is preferable from the viewpoint of improving the reaction rate that the added ruthenium-containing acidic solution is quickly dispersed in the oxidizing agent solution in the reaction tank 1, it is preferable to provide a stirring means in the reaction tank 1, Examples thereof include bubbling with supplied air and mechanical stirring with a screw. In FIG. 1, the heater 2 has a stirring function, and stirring is performed by putting a stirring bar in the reaction tank 1.
以下、実験例を挙げて本発明をより具体的に説明するが、本発明はもとより下記実験例によって制限を受けるものではなく、前・後記の趣旨に適合し得る範囲で適当に変更を加えて実施することも勿論可能であり、それらはいずれも本発明の技術的範囲に包含される。 Hereinafter, the present invention will be described more specifically with reference to experimental examples.However, the present invention is not limited by the following experimental examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.
実験１（発明例）
（ルテニウム含有酸性溶液）
ルテニウム含有材料を塩酸で溶解させたルテニウム含有塩酸酸性溶液に水酸化ナトリウムを添加してｐＨを０．５に調整したルテニウム含有酸性溶液（ルテニウム濃度：５０ｇ／Ｌ、白金濃度：２．５ｇ／Ｌ）を作製した。
Experiment 1 (Invention example)
(Ruthenium-containing acidic solution)
Ruthenium-containing acidic solution in which ruthenium-containing material is dissolved in hydrochloric acid and sodium hydroxide is added to adjust the pH to 0.5 by adding sodium hydroxide (ruthenium concentration: 50 g / L, platinum concentration: 2.5 g / L) ) Was produced.
（酸化剤溶液）
塩酸でｐＨ＝１に調整した水に臭素酸ナトリウムを溶解し、臭素酸ナトリウム２５０ｇ／Ｌの酸化剤溶液を作製した。
(Oxidant solution)
Sodium bromate was dissolved in water adjusted to pH = 1 with hydrochloric acid to prepare an oxidizing agent solution of 250 g / L of sodium bromate.
（ルテニウムの蒸留・回収）
図１と同じ構成の蒸留装置を用いて、ルテニウム含有酸性溶液中のルテニウムを酸化蒸留して回収した。具体的には上記酸化剤溶液（０．０４９Ｌ）を反応槽１内に供給した後、温度計８で計測しながら反応槽１内を６０℃に加熱してから、ルテニウム含有酸性溶液（０．１Ｌ）を図示しないルテニウム含有酸性溶液槽から定量ポンプを介して供給路３から反応槽１に添加した。なお、酸化剤溶液の温度は６０℃に保持してルテニウムの蒸留を行った。ルテニウム含有酸性溶液（０．１Ｌ）は４０分かけて反応槽１に添加した（０．１５Ｌ／ｈ）。その際、反応液中に四酸化ルテニウムの分相（オレンジ色の液体）が生じていないか目視で確認すると共にルテニウム濃度や酸化剤溶液のｐＨを測定しながらルテニウム含有酸性溶液を添加した。また蒸留中は、減圧ポンプ４を使って蒸留装置内を減圧状態に維持すると共に、空気供給路５から空気を供給（１Ｌ／ｍｉｎ）した。
(Ruthenium Distillation / Recovery)
The ruthenium in the ruthenium-containing acidic solution was recovered by oxidative distillation using a distillation apparatus having the same configuration as in FIG. Specifically, after supplying the oxidant solution (0.049 L) into the reaction vessel 1, the reaction vessel 1 is heated to 60 ° C. while measuring with a
反応槽１で酸化反応によって揮発した四酸化ルテニウムは、反応槽１の上部に設けた抜き出し管から塩酸（０．０９８Ｌ）が入っているルテニウム吸収槽６（６ａ、６ｂ）に導入して捕集した。塩素ガスと臭素ガスは水酸化ナトリウム（１６％ＮａＯＨ溶液）が入っているガス吸収槽７に導入して捕集した。蒸留はルテニウム含有酸性溶液の添加開始後２時間経過した時点で終了した。 Ruthenium tetroxide volatilized by the oxidation reaction in the reaction tank 1 is introduced into the ruthenium absorption tank 6 (6a, 6b) containing hydrochloric acid (0.098 L) from the extraction tube provided at the top of the reaction tank 1 and collected. did. Chlorine gas and bromine gas were introduced into a gas absorption tank 7 containing sodium hydroxide (16% NaOH solution) and collected. The distillation was completed when 2 hours had elapsed after the start of the addition of the ruthenium-containing acidic solution.
蒸留中、及び蒸留終了後、反応槽１内（反応槽の壁面、及び液中）での二酸化ルテニウムの析出物（黒色物）の有無を目視で調べると共に、四酸化ルテニウムの分相（オレンジ色の液体）の有無を目視で調べた。その結果、二酸化ルテニウムの析出物、および四酸化ルテニウムの分相はなかった。 During distillation and after completion of distillation, the presence or absence of ruthenium dioxide precipitates (black matter) in the reaction vessel 1 (in the reaction vessel wall and in the liquid) is visually checked, and the phase separation of ruthenium tetroxide (orange) The presence or absence of liquid) was examined visually. As a result, there was no ruthenium dioxide precipitate and ruthenium tetroxide phase separation.
またルテニウム溶液の添加を開始後、２時間経過するまで反応液中のルテニウム濃度をＩＣＰ発光分光分析装置で測定した結果を図２に示す。 FIG. 2 shows the results of measuring the ruthenium concentration in the reaction solution with an ICP emission spectroscopic analyzer until 2 hours had elapsed after the start of the addition of the ruthenium solution.
図２に示すように、反応液中のルテニウム濃度は常に１０ｇ／Ｌ（１００００ｍｇ／Ｌ）以下を保っていた。またルテニウム含有酸性溶液の添加終了後、ルテニウム濃度は低下し、ルテニウム含有酸性溶液添加開始後２時間経過した時点のルテニウム濃度は、０．００１ｇ／Ｌ未満であった。 As shown in FIG. 2, the ruthenium concentration in the reaction solution was always kept at 10 g / L (10000 mg / L) or less. Further, after the addition of the ruthenium-containing acidic solution, the ruthenium concentration decreased, and the ruthenium concentration at the time when 2 hours had elapsed after the start of the addition of the ruthenium-containing acidic solution was less than 0.001 g / L.
酸化剤溶液のｐＨを調べたところ、蒸留開始直後のｐＨはおおむね１．４であった。酸化剤溶液のｐＨは、ルテニウム含有酸性溶液の添加終了後（４０分経過後）から徐々に上昇したが、蒸留終了後（２時間経過後）のｐＨは２．３であり、酸化剤溶液のｐＨは酸化剤の最適範囲を維持していた。 When the pH of the oxidant solution was examined, the pH immediately after the start of distillation was about 1.4. The pH of the oxidant solution gradually increased after the end of addition of the ruthenium-containing acidic solution (after 40 minutes), but the pH after the end of distillation (after 2 hours) was 2.3. The pH maintained the optimal range of oxidizer.
蒸留前（添加前）のルテニウム含有酸性溶液、蒸留後（２時間経過後）の反応槽１内の酸化剤溶液、蒸留後の吸収槽６ａ、６ｂの吸収液を採取してＩＣＰ発光分光分析装置によってルテニウム濃度、白金濃度を測定して回収率、および純度を調べた。結果を表１に示す。 A ruthenium-containing acidic solution before distillation (before addition), an oxidizer solution in the reaction tank 1 after distillation (after 2 hours), and an absorption liquid in the absorption tanks 6a and 6b after distillation are collected to obtain an ICP emission spectrometer. Was used to measure the ruthenium concentration and platinum concentration, and the recovery and purity were examined. The results are shown in Table 1.
吸収槽６ａから回収した吸収液のルテニウム濃度は５０．５ｇ／Ｌであったのに対し、白金濃度は０．００１ｇ／Ｌ未満であり、本発明の方法によれば、ルテニウム中の白金を２０ｐｐｍ以下まで低減することができた。 The ruthenium concentration of the absorption liquid recovered from the absorption tank 6a was 50.5 g / L, whereas the platinum concentration was less than 0.001 g / L. According to the method of the present invention, platinum in ruthenium was 20 ppm. It was possible to reduce to the following.
またルテニウム吸収槽６ａ、６ｂから回収した吸収液には、蒸留前ルテニウム含有酸性溶液に含まれていたルテニウムの９９．９％を回収することができた。 Further, 99.9% of ruthenium contained in the ruthenium-containing acidic solution before distillation could be recovered in the absorption liquid recovered from the ruthenium absorption tanks 6a and 6b.
実験２（添加するルテニウム濃度を１００ｇ／Ｌにした例）
（ルテニウム含有酸性溶液）
上記実験１と同様にしてｐＨを０．５に調整したルテニウム含有酸性溶液（ルテニウム濃度：１００ｇ／Ｌ、白金濃度：５．０ｇ／Ｌ）を作製した。
Experiment 2 (example in which the concentration of ruthenium added is 100 g / L)
(Ruthenium-containing acidic solution)
A ruthenium-containing acidic solution (ruthenium concentration: 100 g / L, platinum concentration: 5.0 g / L) having a pH adjusted to 0.5 was prepared in the same manner as in Experiment 1.
（酸化剤溶液）
上記実験１と同じ酸化剤溶液を作製した。
(Oxidant solution)
The same oxidant solution as in Experiment 1 was prepared.
（ルテニウムの蒸留・回収）
ルテニウム含有酸性溶液０．０５Ｌを０．０７５Ｌ／ｈで反応槽１に添加した以外は、上記実験１と同じ方法でルテニウムの蒸留・回収を行った。またルテニウム吸収槽６ａ、６ｂの液量はそれぞれ０．０９９Ｌ、０．０９８Ｌとした。
(Ruthenium Distillation / Recovery)
Ruthenium was distilled and collected in the same manner as in Experiment 1 except that 0.05 L of ruthenium-containing acidic solution was added to the reaction vessel 1 at 0.075 L / h. The liquid amounts of the ruthenium absorption tanks 6a and 6b were 0.099L and 0.098L, respectively.
蒸留中、及び蒸留終了後、反応槽１内（反応槽の壁面、及び液中）を目視で調べた結果、二酸化ルテニウムの析出物、および四酸化ルテニウムの分相は確認できなかった。 As a result of visual inspection of the inside of the reaction tank 1 (the wall of the reaction tank and in the liquid) during and after the distillation, no ruthenium dioxide precipitates and ruthenium tetroxide phase separation could be confirmed.
またルテニウム溶液の添加を開始後、２時間経過するまで反応液中のルテニウム濃度をＩＣＰ発光分光分析装置で測定した結果を図３に示した。 FIG. 3 shows the result of measuring the ruthenium concentration in the reaction solution with an ICP emission spectroscopic analyzer until 2 hours had elapsed after the start of the addition of the ruthenium solution.
図３に示すように、反応液中のルテニウム濃度は常に１５ｇ／Ｌ（１５０００ｍｇ／Ｌ）以下を保っていた。またルテニウム含有酸性溶液の添加終了後、ルテニウム濃度は低下し、ルテニウム含有酸性溶液添加開始後２時間経過した時点のルテニウム濃度は、０．００１ｇ／Ｌ未満であった。 As shown in FIG. 3, the ruthenium concentration in the reaction solution was always kept at 15 g / L (15000 mg / L) or less. Further, after the addition of the ruthenium-containing acidic solution, the ruthenium concentration decreased, and the ruthenium concentration at the time when 2 hours had elapsed after the start of the addition of the ruthenium-containing acidic solution was less than 0.001 g / L.
酸化剤溶液のｐＨを調べたところ、蒸留開始直後はｐＨはおおむね１．４であった。酸化剤溶液のｐＨは、ルテニウム含有酸性溶液の添加終了後（４０分経過後）から徐々に上昇したが、蒸留終了後（２時間経過後）のｐＨは２．３であり、酸化剤溶液のｐＨは酸化剤の最適範囲を維持していた。 When the pH of the oxidant solution was examined, the pH was about 1.4 immediately after the start of distillation. The pH of the oxidant solution gradually increased after the end of addition of the ruthenium-containing acidic solution (after 40 minutes), but the pH after the end of distillation (after 2 hours) was 2.3. The pH maintained the optimal range of oxidizer.
蒸留前（添加前）のルテニウム含有酸性溶液、蒸留後（２時間経過後）の反応槽１内の酸化剤溶液、蒸留後の吸収槽６ａ、６ｂの吸収液を採取してＩＣＰ発光分光分析装置によってルテニウム濃度、白金濃度を測定して回収率、および純度を調べた。結果を表２に示す。 A ruthenium-containing acidic solution before distillation (before addition), an oxidizer solution in the reaction tank 1 after distillation (after 2 hours), and an absorption liquid in the absorption tanks 6a and 6b after distillation are collected to obtain an ICP emission spectrometer. Was used to measure the ruthenium concentration and platinum concentration, and the recovery and purity were examined. The results are shown in Table 2.
吸収槽６ａから回収した吸収液のルテニウム濃度は５０．１ｇ／Ｌであったのに対し、白金濃度は０．００１ｇ／Ｌ未満であり、本発明の方法によれば、ルテニウム中の白金を２０ｐｐｍ以下まで低減することができた。 The ruthenium concentration of the absorption liquid recovered from the absorption tank 6a was 50.1 g / L, whereas the platinum concentration was less than 0.001 g / L. According to the method of the present invention, platinum in ruthenium was 20 ppm. It was possible to reduce to the following.
またルテニウム吸収槽６ａ、６ｂから回収した吸収液には、蒸留前ルテニウム含有酸性溶液に含まれていたルテニウムの９９．９％以上を回収することができた。 Moreover, 99.9% or more of ruthenium contained in the ruthenium-containing acidic solution before distillation could be recovered in the absorption liquid recovered from the ruthenium absorption tanks 6a and 6b.
実験３（温度を８０℃にした例）
（ルテニウム含有酸性溶液）
実験１と同じルテニウム含有酸性溶液を作製した。
Experiment 3 (example of setting the temperature to 80 ° C.)
(Ruthenium-containing acidic solution)
The same ruthenium-containing acidic solution as in Experiment 1 was prepared.
（酸化剤溶液）
上記実験１と同じ酸化剤溶液を作製した。
(Oxidant solution)
The same oxidant solution as in Experiment 1 was prepared.
（ルテニウムの蒸留・回収）
反応槽１内の酸化剤溶液を８０℃まで加温・保持したこと以外は、上記実験１と同じ方法でルテニウムの蒸留・回収を行った。また吸収槽ルテニウム６ａ、６ｂの液量はそれぞれ０．１０２Ｌ、０．１００Ｌとした。
(Ruthenium Distillation / Recovery)
Ruthenium was distilled and collected in the same manner as in Experiment 1 except that the oxidant solution in the reaction vessel 1 was heated and maintained up to 80 ° C. Moreover, the liquid volume of absorption tank ruthenium 6a, 6b was 0.102L and 0.100L, respectively.
蒸留中、及び蒸留終了後、反応槽１内（反応槽の壁面、及び液中）を目視で調べた結果、二酸化ルテニウムの析出物、および四酸化ルテニウムの分相はなかった。 As a result of visual inspection of the inside of the reaction tank 1 (the wall of the reaction tank and in the liquid) during and after the distillation, there was no ruthenium dioxide precipitate and ruthenium tetroxide phase separation.
またルテニウム溶液の添加を開始後、２時間経過するまで反応液中のルテニウム濃度をＩＣＰ発光分光分析装置で測定した結果を図４に示す。 FIG. 4 shows the results of measuring the ruthenium concentration in the reaction solution with an ICP emission spectroscopic analyzer until 2 hours had elapsed after the start of the addition of the ruthenium solution.
図４に示すように、反応液中のルテニウム濃度は常に１０ｇ／Ｌ（１００００ｍｇ／Ｌ）以下を保っていた。またルテニウム含有酸性溶液の添加終了後、ルテニウム濃度は低下し、ルテニウム含有酸性溶液添加開始後２時間経過した時点のルテニウム濃度は、０．００１ｇ／Ｌ未満であった。 As shown in FIG. 4, the ruthenium concentration in the reaction solution was always kept at 10 g / L (10000 mg / L) or less. Further, after the addition of the ruthenium-containing acidic solution, the ruthenium concentration decreased, and the ruthenium concentration at the time when 2 hours had elapsed after the start of the addition of the ruthenium-containing acidic solution was less than 0.001 g / L.
また酸化剤溶液のｐＨを調べたところ、蒸留開始直後のｐＨはおおむね１．４であった。酸化剤溶液のｐＨは、ルテニウム含有酸性溶液の添加終了後（４０分経過後）から徐々に上昇したが、蒸留終了後（２時間経過後）のｐＨは２．４であり、酸化剤溶液のｐＨは酸化剤の最適範囲を維持していた。 Further, when the pH of the oxidant solution was examined, the pH immediately after the start of distillation was about 1.4. The pH of the oxidant solution gradually increased from the end of addition of the ruthenium-containing acidic solution (after 40 minutes), but the pH after the end of distillation (after 2 hours) was 2.4. The pH maintained the optimal range of oxidizer.
蒸留前（添加前）のルテニウム含有酸性溶液、蒸留後（２時間経過後）の反応槽１内の酸化剤溶液、蒸留後の吸収槽６ａ、６ｂの吸収液を採取してＩＣＰ発光分光分析装置によってルテニウム濃度、白金濃度を測定して回収率、および純度を調べた。結果を表３に示す。 A ruthenium-containing acidic solution before distillation (before addition), an oxidizer solution in the reaction tank 1 after distillation (after 2 hours), and an absorption liquid in the absorption tanks 6a and 6b after distillation are collected to obtain an ICP emission spectrometer. Was used to measure the ruthenium concentration and platinum concentration, and the recovery and purity were examined. The results are shown in Table 3.
吸収槽６ａから回収した吸収液のルテニウム濃度は４８．６ｇ／Ｌであったのに対し、白金濃度は０．００２ｇ／Ｌであり、本発明の方法によれば、ルテニウム中の白金を４１ｐｐｍまで低減することができた。またルテニウム吸収槽６ａ、６ｂから回収した吸収液には、蒸留前ルテニウム含有酸性溶液に含まれていたルテニウムの９９．９％以上を回収することができた。 The ruthenium concentration of the absorbing solution recovered from the absorption tank 6a was 48.6 g / L, whereas the platinum concentration was 0.002 g / L. According to the method of the present invention, platinum in ruthenium was reduced to 41 ppm. It was possible to reduce. Moreover, 99.9% or more of ruthenium contained in the ruthenium-containing acidic solution before distillation could be recovered in the absorption liquid recovered from the ruthenium absorption tanks 6a and 6b.
１ 反応槽
２ ヒーター
３ 供給路
４ 減圧ポンプ
５ 空気供給路
６ ルテニウム吸収槽
６ａ ルテニウム吸収槽（１段）
６ｂ ルテニウム吸収槽（２段）
７ ガス吸収槽
８ 温度計
1 Reaction tank 2 Heater 3 Supply path 4 Pressure reducing pump 5
6b Ruthenium absorption tank (two steps)
7
Claims (2)
前記酸化反応は、酸化反応に必要な当量以上の酸化剤を含有する酸化剤溶液中に、前記ルテニウム含有酸性溶液を添加して行うことを特徴とするルテニウムの回収方法。 In a method of recovering ruthenium by oxidizing ruthenium in an acidic solution containing ruthenium to volatile ruthenium tetroxide by an oxidation reaction and distilling it,
The ruthenium recovery method, wherein the oxidation reaction is performed by adding the ruthenium-containing acidic solution to an oxidizing agent solution containing an oxidizing agent of an equivalent amount or more necessary for the oxidation reaction.
The oxidation reaction is performed while adjusting the ruthenium tetroxide concentration in the reaction solution so that ruthenium tetroxide does not phase-divide with the reaction solution in the reaction solution in which the ruthenium-containing acidic solution is added to the oxidant solution. The ruthenium recovery method according to claim 1, which is performed.
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| JP2020090430A (en) * | 2018-12-07 | 2020-06-11 | ▲キン▼鼎奈米科技股▲分▼有限公司 | Manufacturing method of inorganic platinum compound |
| US10865121B2 (en) | 2018-12-07 | 2020-12-15 | Tripod Nano Technology Corporation | Method of making an inorganic platinum compound |
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