WO2018225738A1 - Palladium extraction agent, palladium extraction method, palladium recovery method, method of regenerating palladium extraction agent, and repeated palladium recovery method - Google Patents

Palladium extraction agent, palladium extraction method, palladium recovery method, method of regenerating palladium extraction agent, and repeated palladium recovery method Download PDF

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WO2018225738A1
WO2018225738A1 PCT/JP2018/021569 JP2018021569W WO2018225738A1 WO 2018225738 A1 WO2018225738 A1 WO 2018225738A1 JP 2018021569 W JP2018021569 W JP 2018021569W WO 2018225738 A1 WO2018225738 A1 WO 2018225738A1
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palladium
organic phase
extractant
extraction
extracting
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French (fr)
Japanese (ja)
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山田　学
ラジブ ガンジー ムニヤパン
一寿 芳賀
柴山　敦
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国立大学法人秋田大学
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D11/00—Solvent extraction
    • B01D11/04—Solvent extraction of solutions which are liquid
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B11/00—Obtaining noble metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

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  • the present invention relates to a palladium extractant, a palladium extraction method, a palladium recovery method, a palladium extractant regeneration method, and a palladium repeated recovery method.
  • Electrolytic deposition, ion exchange, and precipitation methods have been proposed for purification in the platinum group metal separation process, but solvent extraction methods are widely adopted from the viewpoint of selectivity, economy, and operability. .
  • Various extractants used for this purpose have been developed and used.
  • dialkyl sulfide is used as a known palladium extractant (for example, Patent Documents 1 and 2), and is characterized by being easily back-extracted with an aqueous ammonia solution.
  • the automobile exhaust gas catalyst containing a platinum group metal is made into an aqueous solution by acid treatment to form an acidic aqueous solution, and a solvent extraction method is applied thereto.
  • a solvent extraction method is applied thereto.
  • DAS when DAS is used, palladium is selectively extracted from an acidic aqueous solution containing palladium, platinum, rhodium, and base metal, but DAS and the acidic aqueous solution are in contact with each other for a long time.
  • the site is subjected to oxidation, and the ability to extract palladium decreases, resulting in poor reusability.
  • DAS also has a problem that the extraction rate of palladium is slow.
  • the first embodiment of the present invention is a palladium extractant containing an alkyl sulfide group-containing disubstituted aromatic compound represented by the following general formula (I) as an active ingredient.
  • R represents an optionally branched hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 5 to 7 carbon atoms, or an aromatic hydrocarbon group having 7 to 8 carbon atoms. .
  • a step of preparing an organic phase containing the palladium extractant of the first aspect palladium is extracted into the organic phase by contacting the acidic aqueous solution containing palladium with the organic phase. This is a method for extracting palladium.
  • the acidic aqueous solution containing palladium is an acid leaching solution obtained by converting a waste containing various metals containing at least palladium into an aqueous solution by acid treatment.
  • the various metals containing at least palladium preferably contain at least one selected from platinum, rhodium, lanthanum, rare earth, zirconium, and base metal in addition to palladium.
  • the organic phase obtained by extracting palladium obtained by the palladium extraction method of the second aspect and a hydrochloric acid aqueous solution containing thiourea are brought into contact with each other, so that palladium is back-extracted into the aqueous phase. It is the recovery method of palladium provided with the process.
  • the palladium-extracted organic phase obtained by the palladium extraction method of the second aspect is brought into contact with a hydrochloric acid aqueous solution containing thiourea to back-extract palladium into the aqueous phase.
  • a method for regenerating a palladium extractant comprising a step of regenerating the palladium extractant of the first form in the organic phase.
  • a first step of preparing an organic phase containing the palladium extractant of the first aspect contacting an acidic aqueous solution containing palladium with the organic phase, thereby bringing palladium into the organic phase.
  • a second step of extracting the palladium into the aqueous phase by bringing the organic phase from which palladium has been extracted into contact with an aqueous hydrochloric acid solution containing thiourea, and the second step and the second step.
  • WHEREIN It further has a 4th process of wash
  • the said 2nd process, 3rd process, and 4th process Is preferably repeated.
  • the palladium extractant of the first form is capable of (1) selectively extracting only palladium from a solution in which platinum, rhodium, base metal and the like are mixed, and (2) in contact with an acidic solution for a long time. (3) It is possible to extract palladium in a short time.
  • the palladium extractant which is the first embodiment of the present invention is a palladium extractant containing an alkyl sulfide group-containing disubstituted aromatic compound represented by the following general formula (I) as an active ingredient.
  • R represents an optionally branched hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 5 to 7 carbon atoms, or an aromatic hydrocarbon group having 7 to 8 carbon atoms. .
  • the palladium extractant of the present invention is crab-capped into the pincer ligand, which is a characteristic of the pincer-type ligand, which is a characteristic of crab-crushing the metal of the pincer ligand.
  • Pd (II) specifically capture with metal reduction
  • R in one molecule may be the same or different, but is preferably the same from the viewpoint of ease of synthesis.
  • R is an optionally branched hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 5 to 7 carbon atoms, or an aromatic hydrocarbon group having 7 to 8 carbon atoms, preferably carbon A linear or branched alkyl group having 1 to 12 carbon atoms, more preferably a linear or branched alkyl group having 6 to 10 carbon atoms, and even more preferably a linear or branched alkyl group having 7 to 9 carbon atoms. And more preferably a linear alkyl group having 7 to 9 carbon atoms.
  • the alkyl sulfide group-containing disubstituted aromatic compound of the general formula (I) can be synthesized by a known method. For example, it can be synthesized by using ⁇ , ⁇ ′-dihydroxy-1,3-diisopropylbenzene as a starting material and reacting it with a predetermined thiol. The reaction can be carried out in the presence of a given catalyst in a given solvent.
  • thiols examples include alkyl thiols such as 1-octanethiol, 1-heptanethiol, 1-nonanethiol, 2-methyl-1-propanethiol, and 2-ethylhexanethiol, and fats such as cyclohexanethiol and cyclohexylthiol.
  • alkyl thiols such as 1-octanethiol, 1-heptanethiol, 1-nonanethiol, 2-methyl-1-propanethiol, and 2-ethylhexanethiol
  • fats such as cyclohexanethiol and cyclohexylthiol
  • aromatic thiols such as cyclic thiol, benzyl mercapton and phenylethyl mercapton.
  • the solvent for example, dichloromethane or dichloroethane can be used.
  • the catalyst
  • the reaction is preferably performed in an inert atmosphere such as a nitrogen atmosphere.
  • the reaction time and reaction temperature are not particularly limited.
  • the reaction time and the reaction temperature are 1 hour or longer, preferably 2 hours or longer, and the reaction is preferably performed near room temperature.
  • the compound of formula (I) can be obtained through a predetermined purification step.
  • the palladium extraction method according to the second aspect of the present invention is a step of preparing an organic phase containing the palladium extractant of the first aspect described above, contacting an acidic aqueous solution containing palladium and the organic phase. A step of extracting palladium into the organic phase.
  • the alkylsulfide group-containing disubstituted aromatic compound represented by the general formula (I) is usually dissolved in a solvent to form an organic phase.
  • the solvent used for the organic phase containing the palladium extractant is a water-insoluble solvent, and two or more solvents may be used in combination.
  • the water-insoluble solvent is not particularly limited as long as the alkyl sulfide group-containing disubstituted aromatic compound represented by the general formula (I) can be dissolved.
  • Mineral oil such as petroleum and kerosene; hexane, heptane, octane, etc.
  • the concentration of the alkylsulfide group-containing disubstituted aromatic compound represented by formula (I) in the organic phase is not particularly limited except that the upper limit is limited by the solubility of the alkylsulfide group-containing disubstituted aromatic compound. If the concentration is too low, the palladium extraction effect cannot be obtained, and therefore, it is usually used in the range of 1 ⁇ 10 ⁇ 3 to 1M.
  • the acid concentration for example, hydrochloric acid concentration, nitric acid concentration, or hydrochloric acid-nitric acid mixed solution concentration in the acidic aqueous solution containing palladium is preferably 0.1 to 8.0 M, and corresponds to a wide range of acid concentrations. can do.
  • the acid contained in the acidic aqueous solution is not particularly limited as long as it is water-soluble, and an inorganic acid can be used.
  • inorganic acids include hydrochloric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, chlorous acid, sulfuric acid, nitric acid, phosphoric acid, hydrogen peroxide, and the like. Two or more kinds of acids may be contained. From the viewpoint of metal solubility, hydrochloric acid, nitric acid, or a mixture thereof is preferred.
  • the concentration of palladium in the acidic aqueous solution containing palladium is not particularly limited, and is usually about 100 to 1000 ppm.
  • the acidic aqueous solution containing palladium is preferably an acid leaching solution obtained by converting a waste containing various metals containing at least palladium into an aqueous solution by acid treatment. By doing so, it becomes possible to exhibit the outstanding recognizability, selectivity, efficiency, and quickness of the palladium extractant of the present invention.
  • the waste in which various metals including at least palladium are mixed include an automobile exhaust gas catalyst.
  • the metal other than palladium contained in the acid leaching solution is not particularly limited, and may include alkali metals, alkaline earth metals, transition metals, 3B metals, etc., and among them, the selectivity of the palladium extractant of the present invention. From the point of exhibiting, it is preferable to include at least one selected from platinum, rhodium, lanthanum, rare earth, zirconium, and base metal. Thereby, the rare and useful palladium can be recycled. Moreover, since the amount of palladium contained in the acid leaching solution after separating palladium can be greatly reduced, it can also be used as an operation for removing palladium. Therefore, this invention can be utilized also as a pre-processing at the time of isolating useful metals other than palladium from the acid leaching solution which turned waste into aqueous solution by acid treatment.
  • the extraction temperature is not particularly limited as long as it is not higher than the boiling point of the solvent to be used, and is usually performed at around room temperature.
  • the extraction operation is performed by bringing the organic phase containing the palladium extractant and the acidic aqueous solution containing palladium into contact with each other by shaking or stirring. Shaking is usually performed about 100 to 500 times per minute.
  • the palladium extractant of the present invention can extract palladium in a short time, and the shaking time is about 30 minutes, and almost the entire amount can be extracted.
  • the shaking time can be appropriately adjusted depending on the conditions of the extractant and the acidic aqueous solution.
  • the lower limit of the shaking time is preferably 5 minutes or more, more preferably 10 minutes or more, and even more preferably 30 minutes or more, and the upper limit is preferably 2 hours or less, more preferably 1 hour or less.
  • the palladium recovery method according to the third aspect of the present invention is a method of bringing palladium into an aqueous phase by bringing an organic phase obtained by extracting palladium into contact with an aqueous hydrochloric acid solution containing thiourea. A back extraction step is provided.
  • the concentration of thiourea in the aqueous hydrochloric acid solution containing thiourea is preferably 0.01M or more, more preferably 0.05M or more, and the upper limit is preferably 1M or less, more preferably 0.5M or less.
  • the lower limit of the hydrochloric acid concentration in the aqueous hydrochloric acid solution containing thiourea is preferably 0.1 M or more, more preferably 0.5 M or more, and the upper limit is preferably 10 M or less, more preferably 5 M or less.
  • the back extraction temperature is not particularly limited as long as it is equal to or lower than the boiling point of the solvent to be used, and is usually performed around room temperature.
  • the back extraction operation is performed by bringing the organic phase from which palladium has been extracted and the aqueous hydrochloric acid solution containing thiourea into contact with each other by shaking or stirring. Shaking is usually performed about 100 to 500 times per minute.
  • the lower limit of the shaking time is preferably 10 minutes or more, more preferably 20 minutes or more, and even more preferably 30 minutes or more, and the upper limit is preferably 3 hours or less, more preferably 2 hours or less.
  • a fourth aspect of the present invention there is provided a method for regenerating a palladium extractant, wherein the palladium-extracted organic phase obtained by the palladium extraction method is brought into contact with a hydrochloric acid aqueous solution containing thiourea to remove palladium. Back-extracting into the phase and regenerating the palladium extractant of the invention in the organic phase.
  • the palladium recovery method according to the third aspect of the present invention is a regeneration method for the palladium extractant according to the fourth aspect from another viewpoint. That is, in the palladium recovery method, after the palladium is back-extracted into the aqueous phase, the extractant of the present invention remains in the regenerated form in the organic phase.
  • the organic phase containing the regenerated palladium extractant is preferably washed with distilled water as necessary, and the temperature and shaking conditions during the washing are the same as those used in the back extraction.
  • a first step of preparing an organic phase containing the palladium extractant of the first aspect contacting an acidic aqueous solution containing palladium and the organic phase.
  • a second step of extracting palladium into the organic phase, and a third step of back extracting palladium into the aqueous phase by contacting the organic phase from which palladium has been extracted with a hydrochloric acid aqueous solution containing thiourea By repeating the second step and the third step, the palladium extractant can be recovered repeatedly by regenerating the palladium extractant and repeatedly recovering palladium.
  • the palladium extractant of the present invention has resistance to an acidic solution, it is not oxidized even if it contacts the acidic solution multiple times.
  • the method further includes a fourth step of washing the organic phase containing the regenerated palladium extractant with distilled water, the second step, It is preferable to repeat the third step and the fourth step.
  • this washing operation when impurities are contained in the organic phase, the impurities can be removed before the next extraction step, and the extraction efficiency in the next extraction step can be increased.
  • E% [M] org / [M] aq, init ⁇ 100
  • [M] org ([M] aq, init ⁇ [M] aq )
  • [M] org concentration of palladium in the organic phase after extraction (ppm)
  • [M] aq, init concentration of palladium in the aqueous phase before extraction (ppm)
  • [M] aq aqueous phase after extraction
  • E1 Example
  • DOS Comparative Example
  • E1 was diluted to 10 mM with a kerosene solvent
  • DOS was diluted to 20 mM with the same solvent.
  • an equal volume of a palladium single solution prepared to a concentration of 100 ppm using 0.1 M to 8.0 M nitric acid was added, and shaken vigorously (300 rpm) for 1 hour to extract palladium into the organic phase. Went.
  • E1 Example
  • DOS Comparative Example
  • E1 was diluted to 10 mM with a kerosene solvent
  • DOS was diluted to 100 mM with the same solvent.
  • an equal volume of a palladium single solution prepared to a concentration of 100 ppm using a mixed solution of 2.0 M hydrochloric acid / 1.0 M nitric acid is added and shaken vigorously (300 rpm). As time passed, palladium was extracted into the organic phase.
  • FIG. 3 shows the change in extraction rate when the shaking time from the hydrochloric acid / nitric acid mixed solution is changed.
  • the (E%) was calculated by Equation (2) Equation (1) described above (Example).
  • An extraction experiment was also performed using a 20 mM solution of DOS diluted with kerosene (Comparative Example). The extraction rate of each metal is shown in FIG. As shown in FIG. 6, DOS was not able to extract the whole amount of palladium, and the extraction rate was 89.6%. Other metals such as cerium and zirconium were also extracted, though slightly, 1.1% and 2.7%, respectively. On the other hand, it was found that E1 can extract almost all of palladium. From this result, it can be concluded that palladium can be selectively and almost completely extracted by bringing the kerosene solution having E1 of 10 mM into contact with the acid solution.
  • the palladium concentration in the aqueous phase was analyzed with an ICP emission analyzer, and the back extraction rate (S%) was calculated by the following formula (3) based on the obtained results.
  • S% [Pd (II)] aq / [Pd (II)] org ⁇ 100 Formula (3),
  • [Pd (II)] aq Palladium concentration in the aqueous phase after back extraction (ppm)
  • [Pd (II)] org Palladium concentration in the organic phase before back extraction (ppm) Table 1 shows the back extraction rate when each back extractant was used.
  • palladium is completely removed by contacting the organic phase containing E1 with an acid leachate obtained by acid treatment of the waste containing various metals including at least palladium discharged from the factory. It is clear that palladium can be recovered by bringing the organic phase from which palladium has been extracted into contact with a hydrochloric acid solution containing thiourea.
  • FIG. 7 shows the E% and S% of the reused extractant.
  • E1 as an extractant does not show a decrease in extraction efficiency and back-extraction efficiency even in a process including 5 extraction operations and back-extraction operations, and almost completely separates palladium. It can be concluded that it can be recovered. That is, it has been clarified that E1 can be repeatedly used without reducing the extraction rate and the back extraction rate by combining the back extractant and washing with distilled water after back extraction.
  • the pincer-type palladium extractant of the present invention has high palladium selectivity, high extraction speed, can be efficiently back-extracted by using a thiourea / hydrochloric acid solution, and can be reused. From these things, it can adapt also to continuous extraction and is useful also from an industrial viewpoint.
  • the compound of formula (I) has advantages that it is easy to synthesize, does not require a purification operation, and is easy to handle.

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Abstract

This palladium extraction agent, which comprises an alkyl-sulfide-group-comprising disubstituted aromatic compound represented by general formula (I) as an active ingredient, can be used to selectively extract only palladium from a solution in which a mixture of platinum, rhodium, base metals, etc., is present, will not oxidize even after extended contact with acidic solutions, and can be used to extract palladium in a short length of time. (In the formula, R represents an optionally branched hydrocarbon group comprising 1–12 carbon atoms, an alicyclic hydrocarbon group comprising 5–7 carbon atoms, or an aromatic hydrocarbon group comprising 7 or 8 carbon atoms.)

Description

パラジウム抽出剤、パラジウムの抽出方法、パラジウムの回収方法、パラジウム抽出剤の再生方法、および、パラジウムの反復回収方法Palladium extractant, palladium extraction method, palladium recovery method, palladium extractant regeneration method, and palladium repeated recovery method
　本発明は、パラジウム抽出剤、パラジウムの抽出方法、パラジウムの回収方法、パラジウム抽出剤の再生方法、および、パラジウムの反復回収方法に関する。 The present invention relates to a palladium extractant, a palladium extraction method, a palladium recovery method, a palladium extractant regeneration method, and a palladium repeated recovery method.
　パラジウム、白金、ロジウムの３種白金族金属の多くは自動車排ガス触媒に使用されている。排ガス規制並びに規制強化が世界的に広がり、これらの金属の需要が高まったため、これらの金属資源の安定確保は難しくなっている。また、その需要の高まりに伴って使用済み自動車排ガス触媒も増加の一途を辿っている。これらの金属は高価であり、資源として貴重な金属であることから、使用後には回収してリユースすることが行われている。
白金族金属を一定量供給するためには、使用済み製品から白金族金属を高効率で分離することが重要となる。 Many of the three platinum group metals, palladium, platinum, and rhodium, are used in automobile exhaust gas catalysts. Exhaust gas regulations and stricter regulations have spread worldwide, and the demand for these metals has increased, making it difficult to ensure the stability of these metal resources. In addition, with increasing demand, used automobile exhaust gas catalysts have been increasing. Since these metals are expensive and valuable as resources, they are collected and reused after use.
In order to supply a certain amount of platinum group metal, it is important to separate the platinum group metal from the used product with high efficiency.
　市販の抽出剤は白金族元素が複数種類存在する際に、これらのうち一種類の白金族元素に選択性を発現することは難しい。特に、パラジウムと白金とは化学的性質が類似していることから分離に難がある。さらに、強酸性下での抽出条件となるため抽出剤の不安定性も重大な解決問題となっており、新規抽出剤の開発が求められている。 When there are a plurality of types of platinum group elements in a commercially available extractant, it is difficult to express selectivity for one type of platinum group element. In particular, palladium and platinum are difficult to separate because of their similar chemical properties. Furthermore, since the extraction conditions are under strong acidity, the instability of the extractant is also a serious problem to be solved, and the development of a new extractant is required.
　白金族金属の分離工程おける精製には、電解析出法、イオン交換法、沈殿法が提案されているが、選択性、経済性及び操作性の点から、溶媒抽出法が広く採用されている。この用途に使用する様々な抽出剤が開発され利用されている。 Electrolytic deposition, ion exchange, and precipitation methods have been proposed for purification in the platinum group metal separation process, but solvent extraction methods are widely adopted from the viewpoint of selectivity, economy, and operability. . Various extractants used for this purpose have been developed and used.
　現在、公知のパラジウム抽出剤として用いられているのがジアルキルスルフィド（ＤＡＳ）であり（例えば、特許文献１、２）、アンモニア水溶液により容易に逆抽出できることが特徴である。 Currently, dialkyl sulfide (DAS) is used as a known palladium extractant (for example, Patent Documents 1 and 2), and is characterized by being easily back-extracted with an aqueous ammonia solution.
特開平１０－１３０７４４JP-A-10-130744 特開２００５－１４６３２６JP-A-2005-146326
　白金族金属を含む自動車排ガス触媒は、酸処理により水溶液化させて酸性水溶液とし、これに対して、溶媒抽出法を施す。この条件下で、ＤＡＳを使用した場合には、パラジウム、白金、ロジウム、ベースメタルを含む酸性水溶液からパラジウムを選択的に抽出するものの、ＤＡＳと酸性水溶液とが長時間接触するため、ＤＡＳのスルフィド部位が酸化を受け、パラジウムの抽出能力が低下してしまい、再利用性に乏しい。さらに、ＤＡＳはパラジウムの抽出速度が遅いという問題もある。 The automobile exhaust gas catalyst containing a platinum group metal is made into an aqueous solution by acid treatment to form an acidic aqueous solution, and a solvent extraction method is applied thereto. Under these conditions, when DAS is used, palladium is selectively extracted from an acidic aqueous solution containing palladium, platinum, rhodium, and base metal, but DAS and the acidic aqueous solution are in contact with each other for a long time. The site is subjected to oxidation, and the ability to extract palladium decreases, resulting in poor reusability. Furthermore, DAS also has a problem that the extraction rate of palladium is slow.
　以上、本発明は、（１）白金及びロジウム、ベースメタル等が混在する溶液から選択的にパラジウムのみを抽出することが可能であり、（２）酸性溶液と長時間接触しても酸化されず、（３）短時間でパラジウムを抽出することが可能である、パラジウム抽出剤を提供することを課題とする。 As described above, according to the present invention, (1) it is possible to selectively extract only palladium from a solution in which platinum, rhodium, base metal, etc. are mixed, and (2) it is not oxidized even when contacted with an acidic solution for a long time. (3) It is an object to provide a palladium extractant that can extract palladium in a short time.
　本発明者は、鋭意検討の結果、抽出剤の構造を特定のピンサー型構造とすることにより、上記課題を解決可能であることを見出した。 As a result of intensive studies, the present inventor has found that the above problem can be solved by making the extractant structure a specific pincer structure.
　本発明の第１の形態は、下記一般式（Ｉ）で示されるアルキルスルフィド基含有２置換芳香族化合物を有効成分とするパラジウム抽出剤である。 The first embodiment of the present invention is a palladium extractant containing an alkyl sulfide group-containing disubstituted aromatic compound represented by the following general formula (I) as an active ingredient.
Figure JPOXMLDOC01-appb-C000002
 （式中、Ｒは分岐していてもよい炭素数１～１２の炭化水素基、炭素数５～７の脂環式炭化水素基、または、炭素数７～８の芳香族炭化水素基を表す。）
Figure JPOXMLDOC01-appb-C000002
 (In the formula, R represents an optionally branched hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 5 to 7 carbon atoms, or an aromatic hydrocarbon group having 7 to 8 carbon atoms. .)
　本発明の第２の形態は、第１の形態のパラジウム抽出剤を含有する有機相を準備する工程、パラジウムを含む酸性水溶液と前記有機相とを接触させることにより、パラジウムを前記有機相に抽出する工程を備えた、パラジウムの抽出方法である。 According to a second aspect of the present invention, a step of preparing an organic phase containing the palladium extractant of the first aspect, palladium is extracted into the organic phase by contacting the acidic aqueous solution containing palladium with the organic phase. This is a method for extracting palladium.
　第２の形態において、前記パラジウムを含む酸性水溶液は、少なくともパラジウムを含む多種の金属が混在する廃棄物を酸処理により水溶液化した酸浸出液であることが好ましい。 In the second embodiment, it is preferable that the acidic aqueous solution containing palladium is an acid leaching solution obtained by converting a waste containing various metals containing at least palladium into an aqueous solution by acid treatment.
　第２の形態において、前記少なくともパラジウムを含む多種の金属は、パラジウム以外に、白金、ロジウム、ランタン、レアアース、ジルコニウム、および、ベースメタルから選ばれる少なくとも１種を含むことが好ましい。 In the second embodiment, the various metals containing at least palladium preferably contain at least one selected from platinum, rhodium, lanthanum, rare earth, zirconium, and base metal in addition to palladium.
　本発明の第３の形態は、第２の形態のパラジウムの抽出方法により得られたパラジウムを抽出した有機相と、チオ尿素を含む塩酸水溶液とを接触させて、パラジウムを水相に逆抽出する工程を備えたパラジウムの回収方法である。 In the third aspect of the present invention, the organic phase obtained by extracting palladium obtained by the palladium extraction method of the second aspect and a hydrochloric acid aqueous solution containing thiourea are brought into contact with each other, so that palladium is back-extracted into the aqueous phase. It is the recovery method of palladium provided with the process.
　本発明の第４の形態は、第２の形態のパラジウムの抽出方法により得られたパラジウムを抽出した有機相と、チオ尿素を含む塩酸水溶液とを接触させて、パラジウムを水相に逆抽出すると共に、有機相中の第１の形態のパラジウム抽出剤を再生させる工程を備えた、パラジウム抽出剤の再生方法である。 In the fourth aspect of the present invention, the palladium-extracted organic phase obtained by the palladium extraction method of the second aspect is brought into contact with a hydrochloric acid aqueous solution containing thiourea to back-extract palladium into the aqueous phase. A method for regenerating a palladium extractant comprising a step of regenerating the palladium extractant of the first form in the organic phase.
　本発明の第５の形態は、第１の形態のパラジウム抽出剤を含有する有機相を準備する第１工程、パラジウムを含む酸性水溶液と前記有機相とを接触させることにより、パラジウムを前記有機相に抽出する第２工程、および、パラジウムを抽出した有機相と、チオ尿素を含む塩酸水溶液とを接触させて、パラジウムを水相に逆抽出する第３工程を備え、前記第２工程および前記第３工程を繰り返し行うことにより、パラジウム抽出剤を再生しつつ、パラジウムを繰り返して回収可能なパラジウムの反復回収方法である。 According to a fifth aspect of the present invention, there is provided a first step of preparing an organic phase containing the palladium extractant of the first aspect, contacting an acidic aqueous solution containing palladium with the organic phase, thereby bringing palladium into the organic phase. A second step of extracting the palladium into the aqueous phase by bringing the organic phase from which palladium has been extracted into contact with an aqueous hydrochloric acid solution containing thiourea, and the second step and the second step. This is a method for repeatedly collecting palladium by repeatedly performing three steps to regenerate the palladium extractant while repeatedly collecting palladium.
　第５の形態において、前記第３工程の後に、再生したパラジウム抽出剤を含有する有機相を蒸留水により洗浄する第４工程をさらに備え、前記第２工程、第３工程、および、第４工程を繰り返し行うことが好ましい。 5th form WHEREIN: It further has a 4th process of wash | cleaning the organic phase containing the regenerated palladium extractant with distilled water after the said 3rd process, The said 2nd process, 3rd process, and 4th process Is preferably repeated.
　第１の形態のパラジウム抽出剤は、（１）白金及びロジウム、ベースメタル等が混在する溶液から選択的にパラジウムのみを抽出することが可能であり、（２）酸性溶液と長時間接触しても酸化されず、（３）短時間でパラジウムを抽出することが可能である。 The palladium extractant of the first form is capable of (1) selectively extracting only palladium from a solution in which platinum, rhodium, base metal and the like are mixed, and (2) in contact with an acidic solution for a long time. (3) It is possible to extract palladium in a short time.
塩酸濃度に対する抽出率を示すグラフである。It is a graph which shows the extraction rate with respect to hydrochloric acid concentration. 硝酸濃度に対する抽出率を示すグラフである。It is a graph which shows the extraction rate with respect to nitric acid concentration. 塩酸／硝酸混合溶液からパラジウムを抽出する際の抽出率の時間依存性を示すグラフである。It is a graph which shows the time dependence of the extraction rate at the time of extracting palladium from hydrochloric acid / nitric acid mixed solution. 塩酸溶液からパラジウムを抽出する際の抽出率の時間依存性を示すグラフである。It is a graph which shows the time dependence of the extraction rate at the time of extracting palladium from hydrochloric acid solution. パラジウム、白金、ロジウム、レアアース、ジルコニウム、及びベースメタル共存酸性溶液からパラジウムを抽出する際の選択性を示す図である。It is a figure which shows the selectivity at the time of extracting palladium from palladium, platinum, rhodium, a rare earth, a zirconium, and base metal coexistence acidic solution. 自動車排ガス触媒を酸浸出した溶液からパラジウムを抽出する際の選択性を示す図である。It is a figure which shows the selectivity at the time of extracting palladium from the solution which carried out the acid leaching of the automobile exhaust gas catalyst. パラジウムを繰り返し抽出した際の、抽出率（Ｅ％）および逆抽出率（Ｓ％）を示す図である。It is a figure which shows the extraction rate (E%) and back extraction rate (S%) at the time of extracting palladium repeatedly.
　＜パラジウム抽出剤＞
　本発明の第一の形態であるパラジウム抽出剤は、下記一般式（Ｉ）で示されるアルキルスルフィド基含有２置換芳香族化合物を有効成分とするパラジウム抽出剤である。 <Palladium extractant>
The palladium extractant which is the first embodiment of the present invention is a palladium extractant containing an alkyl sulfide group-containing disubstituted aromatic compound represented by the following general formula (I) as an active ingredient.
Figure JPOXMLDOC01-appb-C000003
 （式中、Ｒは分岐していてもよい炭素数１～１２の炭化水素基、炭素数５～７の脂環式炭化水素基、または、炭素数７～８の芳香族炭化水素基を表す。）
Figure JPOXMLDOC01-appb-C000003
 (In the formula, R represents an optionally branched hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 5 to 7 carbon atoms, or an aromatic hydrocarbon group having 7 to 8 carbon atoms. .)
　本発明者は、本発明のパラジウム抽出剤は、ピンサー型配位子の特性である「ピンサー配位子の金属をカニばさみする特性」及び「ピンサー配位子にカニばさみされる金属の還元を伴った特異的な捕捉（Ｐｄ（ＩＩ）をＰｄ（Ｉ）として捕捉）」を利用したことにより、パラジウム抽出剤として優れた認識性・選択性・効率性・迅速性を発揮できたと予測している。 The present inventor has found that the palladium extractant of the present invention is crab-capped into the pincer ligand, which is a characteristic of the pincer-type ligand, which is a characteristic of crab-crushing the metal of the pincer ligand. By using “specific capture with metal reduction (Pd (II) is captured as Pd (I))”, it is possible to demonstrate excellent recognition, selectivity, efficiency and speed as a palladium extractant. I have predicted.
　一般式（Ｉ）において、一分子中のＲは同一であっても異なっていてもよいが、合成のしやすさの点から、同一であることが好ましい。Ｒは分岐していてもよい炭素数１～１２の炭化水素基、炭素数５～７の脂環式炭化水素基、または、炭素数７～８の芳香族炭化水素基であり、好ましくは炭素数１～１２の直鎖または分岐のアルキル基であり、より好ましくは炭素数６～１０の直鎖または分岐のアルキル基であり、さらに好ましくは炭素数７～９の直鎖または分岐のアルキル基であり、さらに好ましくは、炭素数７～９の直鎖のアルキル基である。 In general formula (I), R in one molecule may be the same or different, but is preferably the same from the viewpoint of ease of synthesis. R is an optionally branched hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 5 to 7 carbon atoms, or an aromatic hydrocarbon group having 7 to 8 carbon atoms, preferably carbon A linear or branched alkyl group having 1 to 12 carbon atoms, more preferably a linear or branched alkyl group having 6 to 10 carbon atoms, and even more preferably a linear or branched alkyl group having 7 to 9 carbon atoms. And more preferably a linear alkyl group having 7 to 9 carbon atoms.
　（アルキルスルフィド基含有２置換芳香族化合物の合成方法）
　一般式（Ｉ）のアルキルスルフィド基含有２置換芳香族化合物は、公知の方法で合成できる。例えば、α，α´－ジヒドロキシ－１，３－ジイソプロピルベンゼンを出発物質とし、これと所定のチオールとを反応させることにより合成することができる。反応は、所定の溶媒中で、所定の触媒の存在化において行うことができる。チオールとしては、例えば、１－オクタンチオール、１－ヘプタンチオール、１－ノナンチオール、２-メチル-１-プロパンチオール、２-エチルヘキサンチオール等のアルキルチオール、シクロヘキサンチオールやシクロへキシルチオール等の脂環式チオール、ベンジルメルカプトンやフェニルエチルメルカプトン等の芳香族チオールが挙げられる。
　溶媒としては、例えば、ジクロロメタン、ジクロロエタンを使用することができる。触媒としては、例えば、ヨウ化亜鉛を使用することができる。
　反応は、例えば、窒素雰囲気等の不活性雰囲気において行うことが好ましい。反応時間、反応温度は特に限定されないが、例えば、１時間以上、好ましくは２時間以上であり、室温付近において反応させることが好ましい。反応後は、所定の精製工程を経て、式（Ｉ）の化合物を得ることができる。 (Synthesis method of alkyl sulfide group-containing disubstituted aromatic compound)
The alkyl sulfide group-containing disubstituted aromatic compound of the general formula (I) can be synthesized by a known method. For example, it can be synthesized by using α, α′-dihydroxy-1,3-diisopropylbenzene as a starting material and reacting it with a predetermined thiol. The reaction can be carried out in the presence of a given catalyst in a given solvent. Examples of thiols include alkyl thiols such as 1-octanethiol, 1-heptanethiol, 1-nonanethiol, 2-methyl-1-propanethiol, and 2-ethylhexanethiol, and fats such as cyclohexanethiol and cyclohexylthiol. Examples thereof include aromatic thiols such as cyclic thiol, benzyl mercapton and phenylethyl mercapton.
As the solvent, for example, dichloromethane or dichloroethane can be used. As the catalyst, for example, zinc iodide can be used.
The reaction is preferably performed in an inert atmosphere such as a nitrogen atmosphere. The reaction time and reaction temperature are not particularly limited. For example, the reaction time and the reaction temperature are 1 hour or longer, preferably 2 hours or longer, and the reaction is preferably performed near room temperature. After the reaction, the compound of formula (I) can be obtained through a predetermined purification step.
　＜パラジウムの抽出方法＞
　本発明の第二の形態である、パラジウムの抽出方法は、上記した第一の形態のパラジウム抽出剤を含有する有機相を準備する工程、パラジウムを含む酸性水溶液と前記有機相とを接触させることにより、パラジウムを前記有機相に抽出する工程、を備えている。本発明のパラジウムの抽出方法を実施する場合において、通常、一般式（Ｉ）で表されるアルキルスルフィド基含有２置換芳香族化合物は溶媒に溶解され有機相とされる。該有機相に、パラジウムが溶解した酸性水溶液を接触させることにより、パラジウムが有機相に移行し、パラジウムが抽出される。 <Palladium extraction method>
The palladium extraction method according to the second aspect of the present invention is a step of preparing an organic phase containing the palladium extractant of the first aspect described above, contacting an acidic aqueous solution containing palladium and the organic phase. A step of extracting palladium into the organic phase. In carrying out the palladium extraction method of the present invention, the alkylsulfide group-containing disubstituted aromatic compound represented by the general formula (I) is usually dissolved in a solvent to form an organic phase. By contacting the organic phase with an acidic aqueous solution in which palladium is dissolved, palladium moves to the organic phase and palladium is extracted.
　（パラジウム抽出剤を含有する有機相）
　パラジウム抽出剤を含有する有機相に使用する溶媒は、非水溶性の溶媒であり、２種以上の溶媒を組み合わせて使用してもよい。非水溶性の溶媒としては、一般式（Ｉ）で表されるアルキルスルフィド基含有２置換芳香族化合物を溶解することができれば特に制限はなく、石油、ケロシン等の鉱油；ヘキサン、ヘプタン、オクタン等の脂肪族炭化水素；トルエン、キシレン等の芳香族炭化水素；四塩化炭素、塩化メチレン、クロロホルム、塩化エチレン等のハロゲン化溶媒等が挙げられる。 (Organic phase containing palladium extractant)
The solvent used for the organic phase containing the palladium extractant is a water-insoluble solvent, and two or more solvents may be used in combination. The water-insoluble solvent is not particularly limited as long as the alkyl sulfide group-containing disubstituted aromatic compound represented by the general formula (I) can be dissolved. Mineral oil such as petroleum and kerosene; hexane, heptane, octane, etc. Aliphatic hydrocarbons; aromatic hydrocarbons such as toluene and xylene; halogenated solvents such as carbon tetrachloride, methylene chloride, chloroform, and ethylene chloride.
　有機相における、一般式（Ｉ）で表されるアルキルスルフィド基含有２置換芳香族化合物の濃度は該アルキルスルフィド基含有２置換芳香族化合物の溶解度によって上限が限定される以外は特に制限はないが、あまりに濃度が低いとパラジウム抽出効果が得られないため、通常１×１０－３～１Ｍの範囲で使用される。 The concentration of the alkylsulfide group-containing disubstituted aromatic compound represented by formula (I) in the organic phase is not particularly limited except that the upper limit is limited by the solubility of the alkylsulfide group-containing disubstituted aromatic compound. If the concentration is too low, the palladium extraction effect cannot be obtained, and therefore, it is usually used in the range of 1 × 10 −3 to 1M.
　（パラジウムを含む酸性水溶液）
　パラジウムを含む酸性水溶液における、酸の濃度、例えば、塩酸濃度、硝酸濃度、または、塩酸－硝酸混合溶液の濃度は、好ましくは、０．１から８．０Ｍであり、幅広い範囲の酸濃度に対応することができる。 (Acid aqueous solution containing palladium)
The acid concentration, for example, hydrochloric acid concentration, nitric acid concentration, or hydrochloric acid-nitric acid mixed solution concentration in the acidic aqueous solution containing palladium is preferably 0.1 to 8.0 M, and corresponds to a wide range of acid concentrations. can do.
　酸性水溶液に含まれる酸としては、水溶性であれば特に制限はなく、無機酸を使用することができる。無機酸としては、塩酸、臭化水素酸、ヨウ化水素酸、次亜塩素酸、亜塩素酸、硫酸、硝酸、リン酸、過酸化水素等が挙げられる。また、２種類以上の酸が含まれていても良い。金属の溶解性の観点から、塩酸、硝酸、または、これらの混合物が好ましい。 The acid contained in the acidic aqueous solution is not particularly limited as long as it is water-soluble, and an inorganic acid can be used. Examples of inorganic acids include hydrochloric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, chlorous acid, sulfuric acid, nitric acid, phosphoric acid, hydrogen peroxide, and the like. Two or more kinds of acids may be contained. From the viewpoint of metal solubility, hydrochloric acid, nitric acid, or a mixture thereof is preferred.
　パラジウムを含む酸性水溶液中におけるパラジウムの濃度は特に制限はなく、通常は１００～１０００ｐｐｍ程度である。 The concentration of palladium in the acidic aqueous solution containing palladium is not particularly limited, and is usually about 100 to 1000 ppm.
　本発明の抽出方法において、前記パラジウムを含む酸性水溶液は、少なくともパラジウムを含む多種の金属が混在する廃棄物を酸処理により水溶液化した酸浸出液であることが好ましく、このような酸浸出液を対象とすることにより、本発明のパラジウム抽出剤の優れた認識性、選択制、効率性、迅速性をより発揮させることが可能となる。少なくともパラジウムを含む多種の金属が混在する廃棄物としては、例えば、自動車排ガス触媒を挙げることができる。 In the extraction method of the present invention, the acidic aqueous solution containing palladium is preferably an acid leaching solution obtained by converting a waste containing various metals containing at least palladium into an aqueous solution by acid treatment. By doing so, it becomes possible to exhibit the outstanding recognizability, selectivity, efficiency, and quickness of the palladium extractant of the present invention. Examples of the waste in which various metals including at least palladium are mixed include an automobile exhaust gas catalyst.
　酸浸出液に含まれるパラジウム以外の金属としては、特に限定されず、アルカリ金属、アルカリ土類金属、遷移金属、３Ｂ金属等が含まれていても良く、中でも本発明のパラジウムの抽出剤の選択性を発揮する点から、白金、ロジウム、ランタン、レアアース、ジルコニウム、および、ベースメタルから選ばれる少なくとも１種を含むことが好ましい。これにより、希少性が高く有用なパラジウムをリサイクル利用することができる。また、パラジウムを分離した後の酸浸出液に含まれるパラジウムの量を大きく低減させることができるため、パラジウムを除去する操作としても利用できる。よって、本発明は、廃棄物を酸処理により水溶液化した酸浸出液からパラジウム以外の有用金属を単離する際の、前処理としても利用できる。 The metal other than palladium contained in the acid leaching solution is not particularly limited, and may include alkali metals, alkaline earth metals, transition metals, 3B metals, etc., and among them, the selectivity of the palladium extractant of the present invention. From the point of exhibiting, it is preferable to include at least one selected from platinum, rhodium, lanthanum, rare earth, zirconium, and base metal. Thereby, the rare and useful palladium can be recycled. Moreover, since the amount of palladium contained in the acid leaching solution after separating palladium can be greatly reduced, it can also be used as an operation for removing palladium. Therefore, this invention can be utilized also as a pre-processing at the time of isolating useful metals other than palladium from the acid leaching solution which turned waste into aqueous solution by acid treatment.
　（抽出条件）
　抽出温度は使用する溶媒の沸点以下であれば特に制限はなく、通常、室温付近で行われる。抽出操作はパラジウム抽出剤を含有する有機相とパラジウムを含む酸性水溶液とを振とう、撹拌などにより互いに接触させることにより行われる。振とうは通常毎分１００～５００回程度行えばよい。
　また、本発明のパラジウム抽出剤は短時間でパラジウムを抽出することが可能であり、振とう時間は、３０分程度でほぼ全量の抽出が可能となる。また、抽出剤や酸性水溶液の条件によって、適宜、振とう時間を調整することができる。振とう時間としては、下限が好ましくは５分以上、より好ましくは１０分以上、さらに好ましは３０分以上であり、上限は好ましくは２時間以下、より好ましくは１時間以下である。 (Extraction condition)
The extraction temperature is not particularly limited as long as it is not higher than the boiling point of the solvent to be used, and is usually performed at around room temperature. The extraction operation is performed by bringing the organic phase containing the palladium extractant and the acidic aqueous solution containing palladium into contact with each other by shaking or stirring. Shaking is usually performed about 100 to 500 times per minute.
Moreover, the palladium extractant of the present invention can extract palladium in a short time, and the shaking time is about 30 minutes, and almost the entire amount can be extracted. Moreover, the shaking time can be appropriately adjusted depending on the conditions of the extractant and the acidic aqueous solution. The lower limit of the shaking time is preferably 5 minutes or more, more preferably 10 minutes or more, and even more preferably 30 minutes or more, and the upper limit is preferably 2 hours or less, more preferably 1 hour or less.
　＜パラジウムの回収方法＞
　本発明の第三の形態であるパラジウムの回収方法は、上記したパラジウムの抽出方法により得られたパラジウムを抽出した有機相と、チオ尿素を含む塩酸水溶液とを接触させて、パラジウムを水相に逆抽出する工程を備えている。 <Palladium recovery method>
The palladium recovery method according to the third aspect of the present invention is a method of bringing palladium into an aqueous phase by bringing an organic phase obtained by extracting palladium into contact with an aqueous hydrochloric acid solution containing thiourea. A back extraction step is provided.
　（チオ尿素を含む塩酸水溶液）
　チオ尿素を含む塩酸水溶液における、チオ尿素の濃度は、下限が好ましくは０．０１Ｍ以上、より好ましくは０．０５Ｍ以上であり、上限が好ましくは１Ｍ以下、より好ましくは０．５Ｍ以下である。 (HCl aqueous solution containing thiourea)
The concentration of thiourea in the aqueous hydrochloric acid solution containing thiourea is preferably 0.01M or more, more preferably 0.05M or more, and the upper limit is preferably 1M or less, more preferably 0.5M or less.
　また、チオ尿素を含む塩酸水溶液における、塩酸濃度は、下限が好ましくは０．１Ｍ以上、より好ましくは０．５Ｍ以上であり、上限が好ましくは１０Ｍ以下、より好ましくは５Ｍ以下である。 The lower limit of the hydrochloric acid concentration in the aqueous hydrochloric acid solution containing thiourea is preferably 0.1 M or more, more preferably 0.5 M or more, and the upper limit is preferably 10 M or less, more preferably 5 M or less.
　（逆抽出条件）
　逆抽出温度は使用する溶媒の沸点以下であれば特に制限はなく、通常室温付近で行われる。逆抽出操作はパラジウムを抽出した有機相とチオ尿素を含む塩酸水溶液とを振とう、撹拌などにより互いに接触させることにより行われる。振とうは通常毎分１００～５００回程度行えばよい。振とう時間としては、下限が好ましくは１０分以上、より好ましくは２０分以上、さらに好ましは３０分以上であり、上限は好ましくは３時間以下、より好ましくは２時間以下である。 (Back extraction condition)
The back extraction temperature is not particularly limited as long as it is equal to or lower than the boiling point of the solvent to be used, and is usually performed around room temperature. The back extraction operation is performed by bringing the organic phase from which palladium has been extracted and the aqueous hydrochloric acid solution containing thiourea into contact with each other by shaking or stirring. Shaking is usually performed about 100 to 500 times per minute. The lower limit of the shaking time is preferably 10 minutes or more, more preferably 20 minutes or more, and even more preferably 30 minutes or more, and the upper limit is preferably 3 hours or less, more preferably 2 hours or less.
　以上の逆抽出により、ほぼ全量のパラジウムを有機相から水相に回収することができる。 By the above back extraction, almost the whole amount of palladium can be recovered from the organic phase to the aqueous phase.
　＜パラジウム抽出剤の再生方法＞
　本発明の第四の形態であるパラジウム抽出剤の再生方法は、上記したパラジウムの抽出方法により得られたパラジウムを抽出した有機相と、チオ尿素を含む塩酸水溶液とを接触させて、パラジウムを水相に逆抽出すると共に、有機相中の本発明のパラジウム抽出剤を再生させる工程を備えている。 <Regeneration method of palladium extractant>
According to a fourth aspect of the present invention, there is provided a method for regenerating a palladium extractant, wherein the palladium-extracted organic phase obtained by the palladium extraction method is brought into contact with a hydrochloric acid aqueous solution containing thiourea to remove palladium. Back-extracting into the phase and regenerating the palladium extractant of the invention in the organic phase.
　本発明の第三の形態であるパラジウムの回収方法は、別の観点から見ると、第四の形態のパラジウム抽出剤の再生方法となる。つまり、パラジウムの回収方法において、パラジウムを水相に逆抽出した後は、有機相には本発明の抽出剤が再生された形で残存していることになる。 The palladium recovery method according to the third aspect of the present invention is a regeneration method for the palladium extractant according to the fourth aspect from another viewpoint. That is, in the palladium recovery method, after the palladium is back-extracted into the aqueous phase, the extractant of the present invention remains in the regenerated form in the organic phase.
　再生したパラジウム抽出剤を含有する有機相は必要に応じて、蒸留水により洗浄することが好ましく、該洗浄の際の温度、振とう条件は上記逆抽出の際における条件と同様である。 The organic phase containing the regenerated palladium extractant is preferably washed with distilled water as necessary, and the temperature and shaking conditions during the washing are the same as those used in the back extraction.
　＜パラジウムの反復回収方法＞
　本発明の第５の形態であるパラジウムの反復回収方法は、第１の形態のパラジウム抽出剤を含有する有機相を準備する第１工程、パラジウムを含む酸性水溶液と前記有機相とを接触させることにより、パラジウムを前記有機相に抽出する第２工程、および、パラジウムを抽出した有機相と、チオ尿素を含む塩酸水溶液とを接触させて、パラジウムを水相に逆抽出する第３工程を備え、前記第２工程および前記第３工程を繰り返し行うことにより、パラジウム抽出剤を再生しつつ、パラジウムを繰り返して回収可能なパラジウムの反復回収方法である。 <Palladium repetitive recovery method>
In the method for repeatedly collecting palladium according to the fifth aspect of the present invention, a first step of preparing an organic phase containing the palladium extractant of the first aspect, contacting an acidic aqueous solution containing palladium and the organic phase. A second step of extracting palladium into the organic phase, and a third step of back extracting palladium into the aqueous phase by contacting the organic phase from which palladium has been extracted with a hydrochloric acid aqueous solution containing thiourea, By repeating the second step and the third step, the palladium extractant can be recovered repeatedly by regenerating the palladium extractant and repeatedly recovering palladium.
　上記逆抽出では、ほぼ全量のパラジウムを水相に回収することができる。これは、つまり、有機相においてほぼ全量のパラジウム抽出剤がもとの状態（パラジウムに吸着する前の状態）に再生されていることを意味する。また、本発明のパラジウム抽出剤は、酸性溶液対する耐性を有しているため、たとえ酸性溶液と複数回接触したとしても酸化されることはない。 In the back extraction, almost the entire amount of palladium can be recovered in the aqueous phase. This means that almost the entire amount of the palladium extractant is regenerated to the original state (the state before adsorbing to palladium) in the organic phase. Moreover, since the palladium extractant of the present invention has resistance to an acidic solution, it is not oxidized even if it contacts the acidic solution multiple times.
　よって、本発明のパラジウム抽出剤を含有する有機相をパラジウムを含む酸性水溶液と接触させてパラジウムを抽出し、その後、チオ尿素を含む塩酸水溶液と接触させてパラジウムを逆抽出するという操作を、複数回繰り返すことにより、同じパラジウム抽出剤を使用しつつ複数の酸浸出液からパラジウムをくり返し抽出することが可能であり、工業的観点から効率がよい抽出方法である。 Therefore, a plurality of operations in which the organic phase containing the palladium extractant of the present invention is contacted with an acidic aqueous solution containing palladium to extract palladium, and then contacted with an aqueous hydrochloric acid solution containing thiourea to back-extract palladium. By repeating the process, palladium can be repeatedly extracted from a plurality of acid leaching solutions using the same palladium extractant, which is an efficient extraction method from an industrial viewpoint.
　上記した第５の形態のパラジウムの反復回収方法においては、前記第３工程の後に、再生したパラジウム抽出剤を含有する有機相を蒸留水により洗浄する第４工程をさらに備え、前記第２工程、第３工程、および、第４工程を繰り返し行うことが好ましい。この洗浄操作により、有機相中に不純物が含まれている場合にその不純物を、次の抽出工程の前に除去し、次の抽出工程における、抽出効率を上げることができる。 In the above-described method for repeatedly collecting palladium according to the fifth aspect, after the third step, the method further includes a fourth step of washing the organic phase containing the regenerated palladium extractant with distilled water, the second step, It is preferable to repeat the third step and the fourth step. By this washing operation, when impurities are contained in the organic phase, the impurities can be removed before the next extraction step, and the extraction efficiency in the next extraction step can be increased.
　＜ピンサー型のパラジウム抽出剤（Ｅ１）の合成＞ <Synthesis of Pincer type palladium extractant (E1)>
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　２００ｍＬ容の二口フラスコにα，α’－ジヒドロキシ－１，３－ジイソプロピルベンゼン（１．５５ｇ，７．９８ｍｍｏｌ）とヨウ化亜鉛（２．５６ｇ，８．０２ｍｍｏｌ）、１－オクタンチオール（２．４５ｇ，１６．７８ｍｍｏｌ）をジクロロメタン（５０ｍＬ）に加えて、窒素雰囲気下、室温で２時間攪拌した。反応溶液にジクロロメタンをさらに加えて希釈し、３００ｍＬ容の分液ロートに移して水で洗浄した。有機層を１Ｍ水酸化ナトリウム水溶液で洗浄後、無水の硫酸ナトリウムで脱水した。 脱水後の有機層から溶媒を留去することで無色油状物の目的物（収量３．４５ｇ、収率９６%）を得た。
　得られた目的物の分析結果は以下のとおりであった。
FT-IR (ATR) ν/cm－1: 2922 (C-H), 703 (C－S).  1H NMR (300 MHz, CDCl3, TMS) δ 7.76 (s, 1H, ArH), 7.33 (dd, 2H, ArH), 7.26 (t, 1H, ArH), 2.18 (t, 4H, -SCH 2-), 1.70 (s, 12H, -ArC(CH 3)2-), 1.34 (m, 4H, -SCH2CH 2-), 1.30-1.10 (m, 20H, -SCH2CH2(CH 2)5-), 0.85 (t, 6H, -SCH2CH2(CH2)5CH 3). In a 200 mL two-necked flask, α, α′-dihydroxy-1,3-diisopropylbenzene (1.55 g, 7.98 mmol), zinc iodide (2.56 g, 8.02 mmol), 1-octanethiol (2. 45 g, 16.78 mmol) was added to dichloromethane (50 mL), and the mixture was stirred at room temperature for 2 hours under a nitrogen atmosphere. Dichloromethane was further added to the reaction solution for dilution, transferred to a 300 mL separatory funnel and washed with water. The organic layer was washed with 1M aqueous sodium hydroxide solution and then dehydrated with anhydrous sodium sulfate. The solvent was distilled off from the organic layer after dehydration to obtain the desired product (yield 3.45 g, yield 96%) as a colorless oil.
The analysis result of the obtained target product was as follows.
FT-IR (ATR) ν / cm -1 : 2922 (CH), 703 (C-S). 1 H NMR (300 MHz, CDCl 3 , TMS) δ 7.76 (s, 1H, ArH), 7.33 (dd, 2H, Ar H ), 7.26 (t, 1H, Ar H ), 2.18 (t, 4H, -SC H 2- ), 1.70 (s, 12H, -ArC (C H 3 ) 2- ), 1.34 (m, 4H, -SCH 2 C H 2- ), 1.30-1.10 (m, 20H, -SCH 2 CH 2 (C H 2 ) 5- ), 0.85 (t, 6H, -SCH 2 CH 2 (CH 2 ) 5 C H 3 ).
　＜塩酸濃度の異なる溶液からのパラジウム抽出実験＞
　本例では、ピンサー型のパラジウム抽出剤（Ｅ１）をパラジウム抽出剤とした、パラジウム単独酸性溶液からの抽出実験を行った（実施例）。また、公知のパラジウム抽出剤であるＤＡＳの一種のジ－ｎ－オクチルスルフィド（ＤＯＳ）を用いて同様の実験を行った（比較例）。Ｅ１はケロシン溶媒に希釈して１０ｍＭとし、ＤＯＳも同様の溶媒にて希釈して２０ｍＭとした。これら有機相１０ｍＬに、０．１Ｍ～８．０Ｍ塩酸を用いて１００ｐｐｍの濃度に調製したパラジウム単独溶液を等体積加え、１時間、激しく振とう（３００ｒｐｍ）することで、有機相へパラジウムの抽出を行った。
その後、水相中のパラジウム濃度をＩＣＰ発光分析装置にて分析し、その得られた結果をもとに抽出率（Ｅ％）を下記の式（１）と式（２）にて算出した。
Ｅ％＝［Ｍ］ｏｒｇ／［Ｍ］ａｑ，ｉｎｉｔ×１００　　式（１）
［Ｍ］ｏｒｇ＝（［Ｍ］ａｑ，ｉｎｉｔ－［Ｍ］ａｑ）　　式（２）
　ただし、［Ｍ］ｏｒｇ：抽出後の有機相中のパラジウム濃度（ｐｐｍ）、［Ｍ］ａｑ，ｉｎｉｔ：抽出前の水相中のパラジウム濃度（ｐｐｍ）、［Ｍ］ａｑ：抽出後の水相中のパラジウム濃度、
塩酸濃度を変えた際の抽出率の変化を図１に示す。 <Palladium extraction experiment from solutions with different hydrochloric acid concentrations>
In this example, an extraction experiment was performed from an acidic solution of palladium alone using Pincer type palladium extractant (E1) as a palladium extractant (Example). Further, a similar experiment was conducted using a kind of di-n-octyl sulfide (DOS) of DAS which is a known palladium extractant (Comparative Example). E1 was diluted to 10 mM with a kerosene solvent, and DOS was diluted to 20 mM with the same solvent. To 10 mL of these organic phases, add an equal volume of a palladium single solution prepared to a concentration of 100 ppm using 0.1 M to 8.0 M hydrochloric acid, and shake vigorously (300 rpm) for 1 hour to extract palladium into the organic phase. Went.
Thereafter, the palladium concentration in the aqueous phase was analyzed with an ICP emission analyzer, and the extraction rate (E%) was calculated by the following formulas (1) and (2) based on the obtained results.
E% = [M] org / [M] aq, init × 100 Formula (1)
[M] org = ([M] aq, init − [M] aq ) Formula (2)
[M] org : concentration of palladium in the organic phase after extraction (ppm), [M] aq, init : concentration of palladium in the aqueous phase before extraction (ppm), [M] aq : aqueous phase after extraction Palladium concentration in the
The change in the extraction rate when the hydrochloric acid concentration is changed is shown in FIG.
　図１に示すとおり、塩酸濃度が上昇するとともに、抽出剤としてＤＯＳ（●）を用いた場合は、パラジウムの抽出率が約９０％まで減少したが、Ｅ１（■）を用いた場合では、どの塩酸濃度であっても、抽出率に影響がないことがわかった。このことから、塩酸濃度の変化におけるパラジウムの抽出能力に関しては、ＤＯＳよりも、Ｅ１の方が影響を受けず、安定してパラジウムを抽出できると結論付けることができる。酸溶解させる対象物によって、適用される酸濃度は様々であり、酸濃度の調整工程を不要とする観点から、幅広い酸濃度にて使用できる本願発明の抽出剤は好ましい。 As shown in FIG. 1, when the concentration of hydrochloric acid was increased and DOS (●) was used as the extractant, the extraction rate of palladium decreased to about 90%, but when E1 (■) was used, which It was found that the extraction rate was not affected even by the hydrochloric acid concentration. From this, it can be concluded that E1 is not affected more than DOS, and palladium can be extracted stably with respect to the palladium extraction ability in the change of hydrochloric acid concentration. The acid concentration to be applied varies depending on the object to be acid-dissolved, and the extractant of the present invention that can be used in a wide range of acid concentrations is preferable from the viewpoint of eliminating an acid concentration adjustment step.
　＜硝酸濃度の異なる溶液からのパラジウム抽出実験＞
　本例では、抽出剤としてＥ１（実施例）およびＤＯＳ（比較例）を用いた。Ｅ１はケロシン溶媒に希釈して１０ｍＭとし、ＤＯＳも同様の溶媒にて希釈して２０ｍＭとした。これら有機相１０ｍＬに、０．１Ｍ～８．０Ｍ硝酸を用いて１００ｐｐｍの濃度に調製したパラジウム単独溶液を等体積加え、１時間、激しく振とう（３００ｒｐｍ）することで、有機相へパラジウムの抽出を行った。
その後、水相中のパラジウム濃度をＩＣＰ発光分析装置にて分析し、その得られた結果をもとに抽出率（Ｅ％）を上記の式（１）と式（２）にて求めた。硝酸濃度を変えた際の抽出率の変化を図２に示す。 <Palladium extraction experiment from solutions with different nitric acid concentrations>
In this example, E1 (Example) and DOS (Comparative Example) were used as the extractant. E1 was diluted to 10 mM with a kerosene solvent, and DOS was diluted to 20 mM with the same solvent. To 10 mL of these organic phases, an equal volume of a palladium single solution prepared to a concentration of 100 ppm using 0.1 M to 8.0 M nitric acid was added, and shaken vigorously (300 rpm) for 1 hour to extract palladium into the organic phase. Went.
Thereafter, the palladium concentration in the aqueous phase was analyzed with an ICP emission spectrometer, and the extraction rate (E%) was determined by the above formulas (1) and (2) based on the obtained results. The change in extraction rate when the nitric acid concentration is changed is shown in FIG.
　図２からわかるように、硝酸濃度が上昇するとともに、抽出剤としてＤＯＳ（●）を用いた場合は、パラジウムの抽出率が約７０％まで減少したのに対し、Ｅ１（■）を用いた場合では、どの硝酸濃度であっても、抽出率に影響がないことがわかった。このことから、硝酸濃度の変化におけるパラジウムの抽出能力に関しては、ＤＯＳよりも、Ｅ１の方が影響を受けず、安定してパラジウムを抽出できると結論付けることができる。酸溶解させる対象物によって、適用される酸濃度は様々であり、酸濃度の調整工程を不要とする観点から、幅広い酸濃度にて使用できる本願発明の抽出剤は好ましい。 As can be seen from FIG. 2, when the concentration of nitric acid increased and DOS (●) was used as the extractant, the extraction rate of palladium decreased to about 70%, whereas E1 (■) was used. Thus, it was found that the extraction rate was not affected at any nitric acid concentration. From this, it can be concluded that E1 is not affected more than DOS, and palladium can be extracted stably with respect to the ability to extract palladium in the change in nitric acid concentration. The acid concentration to be applied varies depending on the object to be acid-dissolved, and the extractant of the present invention that can be used in a wide range of acid concentrations is preferable from the viewpoint of eliminating an acid concentration adjustment step.
　＜塩酸/硝酸混合溶液からパラジウムを抽出する際の抽出率の時間依存性＞
　本実施例では、抽出剤としてＥ１（実施例）およびＤＯＳ（比較例）を用いた。Ｅ１はケロシン溶媒に希釈して１０ｍＭとし、ＤＯＳも同様の溶媒にて希釈して１００ｍＭとした。これら有機相１０ｍＬに、２．０Ｍ塩酸/１．０Ｍ硝酸を混合した溶液を用いて１００ｐｐｍの濃度に調製したパラジウム単独溶液を等体積加え、激しく振とう（３００ｒｐｍ）し、振とう時間を最長１６８時間までとして、有機相へパラジウムの抽出を行った。
その後、水相中のパラジウム濃度をＩＣＰ発光分析装置にて分析し、抽出率（Ｅ%）を上記の式（１）と式（２）にて求めた。塩酸／硝酸混合溶液中からの振とう時間を変えた際の抽出率の変化を図３に示す。 <Time dependence of extraction rate when extracting palladium from hydrochloric acid / nitric acid mixed solution>
In this example, E1 (Example) and DOS (Comparative Example) were used as the extractant. E1 was diluted to 10 mM with a kerosene solvent, and DOS was diluted to 100 mM with the same solvent. To 10 mL of these organic phases, an equal volume of a palladium single solution prepared to a concentration of 100 ppm using a mixed solution of 2.0 M hydrochloric acid / 1.0 M nitric acid is added and shaken vigorously (300 rpm). As time passed, palladium was extracted into the organic phase.
Thereafter, the palladium concentration in the aqueous phase was analyzed with an ICP emission spectrometer, and the extraction rate (E%) was determined by the above formulas (1) and (2). FIG. 3 shows the change in extraction rate when the shaking time from the hydrochloric acid / nitric acid mixed solution is changed.
　図３からわかるように、振とう時間が増加するごとに、ＤＯＳ（●）を用いた場合は、パラジウムの抽出率が急激に減少し、振とう時間１６８時間付近では約４０％まで低下したが、Ｅ１（■）を用いた場合では、抽出率の減少が見られず、一定の割合で抽出できることがわかる。このことから、塩酸/硝酸混合溶液中であっても、Ｅ１は影響を受けずに安定してパラジウムを抽出できると結論付けることができる。 As can be seen from FIG. 3, every time the shaking time is increased, when DOS (●) is used, the extraction rate of palladium sharply decreases, and it decreases to about 40% around the shaking time of 168 hours. When E1 (■) is used, it can be seen that the extraction rate does not decrease and extraction can be performed at a constant rate. From this, it can be concluded that even in the hydrochloric acid / nitric acid mixed solution, E1 can extract palladium stably without being affected.
　＜パラジウム抽出率の抽出時間依存性＞
　本例では、Ｅ１（実施例）とＤＯＳ（比較例）を用いて実験を行った。Ｅ１はケロシン溶媒に希釈して１０ｍＭとし、ＤＯＳも同様の溶媒にて希釈して２０ｍＭとした。これら有機相１０ｍＬに、８．０Ｍ塩酸を用いて１００ｐｐｍの濃度に調製したパラジウム単独酸性溶液を等体積加え、激しく振とう（３００ｒｐｍ）することで、有機相へパラジウムの抽出を行った。
抽出率は振とう前後の水相のパラジウム濃度をＩＣＰ発光分析装置にて求め、上記の式（１）と式（２）から算出した。振とう時間を変えた際の抽出率の変化を図４に示す。
　図４に示すように、ＤＯＳ（●）を用いた場合では、パラジウムをほぼ全量を抽出するのに、１８０分程度を要するが、Ｅ１（■）を用いた場合は、３０分程度でパラジウムの全量を抽出できることがわかった。パラジウムの抽出時間に関しては、ＤＯＳよりも、Ｅ１の方が速いこと明らかであった。 <Extraction time dependence of palladium extraction rate>
In this example, an experiment was performed using E1 (Example) and DOS (Comparative Example). E1 was diluted to 10 mM with a kerosene solvent, and DOS was diluted to 20 mM with the same solvent. To 10 mL of these organic phases, an equal volume of an acidic solution of palladium alone prepared to a concentration of 100 ppm using 8.0 M hydrochloric acid was added and shaken vigorously (300 rpm) to extract palladium into the organic phase.
The extraction rate was calculated from the above formulas (1) and (2) by determining the palladium concentration in the aqueous phase before and after shaking with an ICP emission spectrometer. FIG. 4 shows changes in the extraction rate when the shaking time is changed.
As shown in FIG. 4, in the case of using DOS (●), it takes about 180 minutes to extract almost the entire amount of palladium, but in the case of using E1 (■), the palladium is extracted in about 30 minutes. It was found that the whole amount can be extracted. Regarding the extraction time of palladium, it was clear that E1 was faster than DOS.
　＜パラジウム、白金、ロジウム、レアアース、ジルコニウム、及びベースメタル共存酸性溶液からパラジウムを抽出する際の選択性＞
　本例では、一次・二次資源からのパラジウム分離精製で用いられる酸性溶液を想定し、パラジウム、白金、ロジウム、レアアース、ジルコニウム、及びベースメタルとしてバリウム、アルミニウム、鉄、銅、亜鉛、ニッケルが共存する、各金属濃度が１００ｐｐｍになるように調製した、３Ｍ塩酸溶液から、Ｅ１をケロシンにて希釈した１０ｍＭの溶液への各金属の抽出率を求めた（実施例）。また、ＤＯＳをケロシンにて希釈した２０ｍＭの溶液も用いて抽出実験を行った（比較例）。有機相と水相とを、１時間激しく振とう（３００ｒｐｍ）し、その後、水相中の各金属の濃度をＩＣＰ発光分析装置にて分析し、その得られた結果をもとに抽出率（Ｅ％）を上記の式（１）と式（２）にて求めた。各金属の抽出率を図５に示す。 <Selectivity when extracting palladium from acidic solution coexisting with palladium, platinum, rhodium, rare earth, zirconium, and base metal>
In this example, an acidic solution used for separation and purification of palladium from primary and secondary resources is assumed, and palladium, platinum, rhodium, rare earth, zirconium, and barium, aluminum, iron, copper, zinc, and nickel as base metals coexist. The extraction rate of each metal from a 3M hydrochloric acid solution prepared so that the concentration of each metal was 100 ppm was obtained in a 10 mM solution in which E1 was diluted with kerosene (Example). An extraction experiment was also performed using a 20 mM solution of DOS diluted with kerosene (Comparative Example). The organic phase and the aqueous phase are shaken vigorously (300 rpm) for 1 hour, and then the concentration of each metal in the aqueous phase is analyzed with an ICP emission spectrometer, and the extraction rate ( E%) was determined by the above formulas (1) and (2). The extraction rate of each metal is shown in FIG.
　図５に示すように、ＤＯＳはパラジウムの全量を抽出できておらず、抽出率８２．２％であった。また、他の金属のジルコニウムや鉄もわずかはであるが抽出されており、それぞれ、３．５％、３．２％であった。一方で、Ｅ１はパラジウムを９９．９％とほぼ全量を抽出でき、その他の金属を抽出しないことがわかった。この結果から、Ｅ１を１０ｍＭとしたケロシン溶液とパラジウム、白金、ロジウム、レアアース、ジルコニウム、及びベースメタルが共存する塩酸溶液とを接触させると、パラジウムは選択的かつほぼ全量抽出できると結論付けることができる。 As shown in FIG. 5, DOS was not able to extract the whole amount of palladium, and the extraction rate was 82.2%. In addition, other metals such as zirconium and iron were extracted although they were a little, which were 3.5% and 3.2%, respectively. On the other hand, it was found that E1 can extract almost the entire amount of palladium as 99.9% and does not extract other metals. From this result, it can be concluded that when a kerosene solution with E1 of 10 mM is brought into contact with a hydrochloric acid solution in which palladium, platinum, rhodium, rare earth, zirconium, and base metal coexist, palladium can be selectively and almost entirely extracted. it can.
　＜自動車排ガス触媒を酸浸出した溶液からパラジウムを抽出した際の選択性＞
　工場より排出された少なくともパラジウムを含む多種の金属が混在する廃棄物を酸処理により水溶液化した酸浸出液を蒸留水にて５倍に希釈した水溶液（Ｐｄ（ＩＩ）：９２．８ｐｐｍ，Ｐｔ（ＩＶ）：５４．２ｐｐｍ，Ｒｈ（ＩＩＩ）：３７．２ｐｐｍ，Ｌａ（ＩＩＩ）：８６．７ｐｍ，Ｃｅ（ＩＩＩ）：６０８．８ｐｐｍ，Ｙ（ＩＩＩ）：３．８ｐｐｍ，Ｚｒ（ＩＶ）：２５．６ｐｐｍ，Ｂａ（ＩＩ）：２８９．３ｐｐｍ，Ａｌ（ＩＩＩ）：３２０．９ｐｐｍ）１０ｍＬ（ｐＨ０．８）を水相とし、Ｅ１をケロシン溶媒に希釈し１０ｍＭとして有機相（１０ｍＬ）とし、これら有機相と水相とを、１時間激しく振とう（３００ｒｐｍ）し、その後、水相中の各金属の濃度をＩＣＰ発光分析装置にて分析し、その得られた結果をもとに抽出率（Ｅ%）を上記の式（１）と式（２）にて求めた（実施例）。
また、ＤＯＳをケロシンにて希釈した２０ｍＭの溶液も用いて抽出実験を行った（比較例）。各金属の抽出率を図６に示す。
　図６に示すように、ＤＯＳはパラジウムの全量を抽出できておらず、抽出率８９．６％であった。また、他の金属のセリウムやジルコニウムもわずかはであるが抽出されており、それぞれ、１．１％、２．７％であった。一方で、Ｅ１はパラジウムをほぼ全量抽出することができることがわかった。この結果から、Ｅ１を１０ｍＭとしたケロシン溶液と前記酸溶液とを接触させると、パラジウムは選択的かつほぼ全量抽出できると結論付けることができる。 <Selectivity when palladium is extracted from a solution obtained by acid leaching of an automobile exhaust gas catalyst>
An aqueous solution (Pd (II): 92.8 ppm, Pt (IV) obtained by diluting an acid leachate obtained by acid treatment of a waste mixed with various metals including at least palladium discharged from a factory with distilled water. ): 54.2 ppm, Rh (III): 37.2 ppm, La (III): 86.7 pm, Ce (III): 608.8 ppm, Y (III): 3.8 ppm, Zr (IV): 25.6 ppm , Ba (II): 289.3 ppm, Al (III): 320.9 ppm) 10 mL (pH 0.8) as the aqueous phase, E1 diluted in kerosene solvent to 10 mM as the organic phase (10 mL), Shake vigorously for 1 hour (300 rpm), then analyze the concentration of each metal in the aqueous phase with an ICP emission spectrometer and extract based on the results obtained. The (E%) was calculated by Equation (2) Equation (1) described above (Example).
An extraction experiment was also performed using a 20 mM solution of DOS diluted with kerosene (Comparative Example). The extraction rate of each metal is shown in FIG.
As shown in FIG. 6, DOS was not able to extract the whole amount of palladium, and the extraction rate was 89.6%. Other metals such as cerium and zirconium were also extracted, though slightly, 1.1% and 2.7%, respectively. On the other hand, it was found that E1 can extract almost all of palladium. From this result, it can be concluded that palladium can be selectively and almost completely extracted by bringing the kerosene solution having E1 of 10 mM into contact with the acid solution.
　＜自動車排ガス触媒を酸浸出した溶液からパラジウムを抽出した有機相から、パラジウムを逆抽出した際の逆抽出率＞
　前記の自動車排ガス触媒を酸浸出した溶液からパラジウムを抽出した後の有機相を分取し、水相として同体積の各１Ｍ塩酸、 １Ｍ硝酸、１Ｍ硫酸、５％アンモニア水溶液、０．１Ｍチオ尿素／１．０Ｍ塩酸溶液を用い、これら有機相および水相を１時間振とうさせ、パラジウムの水相への逆抽出を行った。水相中のパラジウム濃度をＩＣＰ発光分析装置にて分析し、その得られた結果をもとに逆抽出率（Ｓ％）を下記の式（３）にて算出した。
Ｓ％＝［Ｐｄ（ＩＩ）］ａｑ／［Ｐｄ（ＩＩ）］ｏｒｇ×１００　　　式（３）、
ただし、［Ｐｄ（ＩＩ）］ａｑ：逆抽出後の水相中のパラジウム濃度（ｐｐｍ）、［Ｐｄ（ＩＩ）］ｏｒｇ：逆抽出前の有機相中のパラジウム濃度（ｐｐｍ）
　各逆抽出剤を用いたときの逆抽出率を表１に示す。
表１に示すように、Ｅ１によるパラジウムの捕捉力が強いがために、各１Ｍ塩酸、１Ｍ硝酸、１Ｍ硫酸、５％アンモニア水溶液の逆抽出率はそれぞれ、６．５％、１５．１％、８．６％、１０．４％と効率的な逆抽出はできなかった。一方で、０．１Ｍチオ尿素／１．０Ｍ塩酸溶液を用いた場合では、ほぼ全量のパラジウムを有機相から水相へ回収でき、逆抽出率は９９．９％であった。 <Back extraction rate when palladium is back-extracted from an organic phase obtained by extracting palladium from a solution obtained by acid leaching of an automobile exhaust gas catalyst>
The organic phase after extracting palladium from the solution obtained by acid leaching of the automobile exhaust gas catalyst is separated, and each volume of 1M hydrochloric acid, 1M nitric acid, 1M sulfuric acid, 5% ammonia aqueous solution, 0.1M thiourea is used as the aqueous phase. The organic phase and aqueous phase were shaken for 1 hour using a /1.0 M hydrochloric acid solution, and palladium was back-extracted into the aqueous phase. The palladium concentration in the aqueous phase was analyzed with an ICP emission analyzer, and the back extraction rate (S%) was calculated by the following formula (3) based on the obtained results.
S% = [Pd (II)] aq / [Pd (II)] org × 100 Formula (3),
However, [Pd (II)] aq : Palladium concentration in the aqueous phase after back extraction (ppm), [Pd (II)] org : Palladium concentration in the organic phase before back extraction (ppm)
Table 1 shows the back extraction rate when each back extractant was used.
As shown in Table 1, because of the strong trapping ability of palladium by E1, the back extraction rates of 1M hydrochloric acid, 1M nitric acid, 1M sulfuric acid, and 5% ammonia aqueous solution were 6.5%, 15.1%, Back extraction as efficient as 8.6% and 10.4% was not possible. On the other hand, when a 0.1 M thiourea / 1.0 M hydrochloric acid solution was used, almost the entire amount of palladium could be recovered from the organic phase to the aqueous phase, and the back extraction rate was 99.9%.
　すなわち、以上の結果に基づけば、工場より排出された少なくともパラジウムを含む多種の金属が混在する廃棄物を酸処理により水溶液化した酸浸出液に、Ｅ１を含む有機相を接触させることによりパラジウムを完全に分離できること、また、パラジウムが抽出された有機相に、チオ尿素を含む塩酸溶液を接触させることによりパラジウムを回収できることが明らかである。 That is, based on the above results, palladium is completely removed by contacting the organic phase containing E1 with an acid leachate obtained by acid treatment of the waste containing various metals including at least palladium discharged from the factory. It is clear that palladium can be recovered by bringing the organic phase from which palladium has been extracted into contact with a hydrochloric acid solution containing thiourea.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　＜逆抽出後のＥ１を含む有機相を用いて、二次資源の自動車排ガス触媒を酸浸出した溶液からパラジウムを繰り返し抽出＞
　前記のパラジウムが逆抽出された後の有機相を分取し、等体積の蒸留水と、接触させた後、有機相を分取した。この有機相を、前記酸浸出液と、１時間激しく振とう（３００ｒｐｍ）した（Ｅｘｔ．２）。また、前記のように逆抽出を行い（Ｓｔｒ．２）、有機相を蒸留水で洗浄し、前記酸浸出液からパラジウムの抽出実験を行った。このように抽出および逆抽出の操作を全体で５回実施し（Ｅｘｔ．／Ｓｔｒ．１～Ｅｘｔ．／Ｓｔｒ．５）、各回のその後、水相中の各金属の濃度をＩＣＰ発光分析装置にて分析した結果から、上記の式（１）、式（２）および式（３）を用いてＥ％とＳ％を求めた。再利用した抽出剤のＥ％とＳ％を図７に示す。
　図７に示すように、抽出剤としてＥ１は、５回の抽出操作と逆抽出操作を含めた工程であっても、抽出効率及び逆抽出効率の低下は見られず、パラジウムをほぼ全量を分離し、回収することができると結論付けることができる。
　すなわち、Ｅ１は前記逆抽出剤と逆抽出後の蒸留水での洗浄を組み合わせることで、抽出率及び逆抽出率の低下なく、繰り返し利用が可能であることが明らかとなった。 <Palladium is repeatedly extracted from a solution obtained by acid leaching of an automobile exhaust gas catalyst as a secondary resource using an organic phase containing E1 after back extraction>
The organic phase after the palladium was back-extracted was separated and contacted with an equal volume of distilled water, and then the organic phase was separated. The organic phase was vigorously shaken (300 rpm) with the acid leaching solution for 1 hour (Ext. 2). Further, back extraction was performed as described above (Str. 2), the organic phase was washed with distilled water, and palladium was extracted from the acid leaching solution. Thus, the extraction and back-extraction operations were carried out five times in total (Ext./Str. 1 to Ext./Str. 5), and after each round, the concentration of each metal in the aqueous phase was transferred to the ICP emission spectrometer. From the analysis results, E% and S% were determined using the above formula (1), formula (2), and formula (3). FIG. 7 shows the E% and S% of the reused extractant.
As shown in FIG. 7, E1 as an extractant does not show a decrease in extraction efficiency and back-extraction efficiency even in a process including 5 extraction operations and back-extraction operations, and almost completely separates palladium. It can be concluded that it can be recovered.
That is, it has been clarified that E1 can be repeatedly used without reducing the extraction rate and the back extraction rate by combining the back extractant and washing with distilled water after back extraction.
　このように本発明のピンサー型のパラジウム抽出剤は、パラジウムの選択性が高く、抽出速度も速く、チオ尿素/塩酸溶液を用いることで効率良く逆抽出でき、再利用も可能である。これらのことから、連続的な抽出にも適応することができ、工業的な観点からも有用である。また、式（Ｉ）の化合物は、合成が容易であり、精製操作も必要ないこと、取り扱いが容易であるという利点もある。 Thus, the pincer-type palladium extractant of the present invention has high palladium selectivity, high extraction speed, can be efficiently back-extracted by using a thiourea / hydrochloric acid solution, and can be reused. From these things, it can adapt also to continuous extraction and is useful also from an industrial viewpoint. In addition, the compound of formula (I) has advantages that it is easy to synthesize, does not require a purification operation, and is easy to handle.

Claims (8)

  1. 下記一般式（Ｉ）で示されるアルキルスルフィド基含有２置換芳香族化合物を有効成分とするパラジウム抽出剤。
    Figure JPOXMLDOC01-appb-C000001
     （式中、Ｒは分岐していてもよい炭素数１～１２の炭化水素基、炭素数５～７の脂環式炭化水素基、または、炭素数７～８の芳香族炭化水素基を表す。）     A palladium extractant containing an alkyl sulfide group-containing disubstituted aromatic compound represented by the following general formula (I) as an active ingredient.
    Figure JPOXMLDOC01-appb-C000001
     (In the formula, R represents an optionally branched hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 5 to 7 carbon atoms, or an aromatic hydrocarbon group having 7 to 8 carbon atoms. .)
  2. 　請求項１に記載のパラジウム抽出剤を含有する有機相を準備する工程、パラジウムを含む酸性水溶液と前記有機相とを接触させることにより、パラジウムを前記有機相に抽出する工程を備えた、パラジウムの抽出方法。 A step of preparing an organic phase containing the palladium extractant according to claim 1, and a step of extracting palladium into the organic phase by bringing an acidic aqueous solution containing palladium into contact with the organic phase. Extraction method.
  3. 　前記パラジウムを含む酸性水溶液が、少なくともパラジウムを含む多種の金属が混在する廃棄物を酸処理により水溶液化した酸浸出液である、請求項２に記載のパラジウムの抽出方法。 3. The palladium extraction method according to claim 2, wherein the acidic aqueous solution containing palladium is an acid leaching solution obtained by acidifying a waste containing various metals containing at least palladium.
  4. 　前記少なくともパラジウムを含む多種の金属が、パラジウム以外に、白金、ロジウム、ランタン、レアアース、ジルコニウム、および、ベースメタルから選ばれる少なくとも１種を含む、請求項３に記載のパラジウムの抽出方法。 The method for extracting palladium according to claim 3, wherein the various metals containing at least palladium include, in addition to palladium, at least one selected from platinum, rhodium, lanthanum, rare earth, zirconium, and base metal.
  5. 　請求項２に記載のパラジウムの抽出方法により得られたパラジウムを抽出した有機相と、チオ尿素を含む塩酸水溶液とを接触させて、パラジウムを水相に逆抽出する工程を備えたパラジウムの回収方法。 A method for recovering palladium, comprising the step of bringing the organic phase obtained by extracting the palladium obtained by the palladium extraction method according to claim 2 into contact with an aqueous hydrochloric acid solution containing thiourea and back-extracting the palladium into the aqueous phase. .
  6. 　請求項２に記載のパラジウムの抽出方法により得られたパラジウムを抽出した有機相と、チオ尿素を含む塩酸水溶液とを接触させて、パラジウムを水相に逆抽出すると共に、有機相中の請求項１に記載のパラジウム抽出剤を再生させる工程を備えた、パラジウム抽出剤の再生方法。 The organic phase obtained by extracting palladium obtained by the palladium extraction method according to claim 2 is brought into contact with a hydrochloric acid aqueous solution containing thiourea to back-extract palladium into the aqueous phase, and the claim in the organic phase. A method for regenerating a palladium extractant, comprising the step of regenerating the palladium extractant according to 1.
  7. 　請求項１に記載のパラジウム抽出剤を含有する有機相を準備する第１工程、パラジウムを含む酸性水溶液と前記有機相とを接触させることにより、パラジウムを前記有機相に抽出する第２工程、および、パラジウムを抽出した有機相と、チオ尿素を含む塩酸水溶液とを接触させて、パラジウムを水相に逆抽出する第３工程を備え、前記第２工程および前記第３工程を繰り返し行うことにより、パラジウム抽出剤を再生しつつ、パラジウムを繰り返して回収可能なパラジウムの反復回収方法。 A first step of preparing an organic phase containing the palladium extractant according to claim 1, a second step of extracting palladium into the organic phase by contacting an acidic aqueous solution containing palladium and the organic phase, and A third step of contacting the organic phase from which palladium has been extracted with an aqueous hydrochloric acid solution containing thiourea and back-extracting palladium into the aqueous phase, by repeating the second step and the third step, A method for repeatedly collecting palladium, which can be repeatedly recovered while regenerating the palladium extractant.
  8. 　前記第３工程の後に、再生したパラジウム抽出剤を含有する有機相を蒸留水により洗浄する第４工程をさらに備え、前記第２工程、第３工程、および、第４工程を繰り返し行う、請求項７に記載のパラジウムの反復回収方法。 The method further comprises a fourth step of washing the organic phase containing the regenerated palladium extractant with distilled water after the third step, and repeatedly performing the second step, the third step, and the fourth step. 8. The method for repeatedly collecting palladium according to 7.
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JPS62246823A (en) * 1986-04-21 1987-10-28 Daihachi Kagaku Kogyosho:Kk Method for recovering palladium and/or silver
JP2003119032A (en) * 2001-10-17 2003-04-23 Japan Science & Technology Corp Noble metal extraction agent consisting of thioaniline derivative, and method of separating noble metal using the extraction agent
JP2014172838A (en) * 2013-03-07 2014-09-22 Dowa Holdings Co Ltd Novel compounds, metal extractants, and methods of extracting at least one of palladium and platinum

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JPS62246823A (en) * 1986-04-21 1987-10-28 Daihachi Kagaku Kogyosho:Kk Method for recovering palladium and/or silver
JP2003119032A (en) * 2001-10-17 2003-04-23 Japan Science & Technology Corp Noble metal extraction agent consisting of thioaniline derivative, and method of separating noble metal using the extraction agent
JP2014172838A (en) * 2013-03-07 2014-09-22 Dowa Holdings Co Ltd Novel compounds, metal extractants, and methods of extracting at least one of palladium and platinum

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