PRODUCTION METHOD OF HIGH-PURITY Ir POWDER

• Main Authors: WATANABE TOMONOBU, SUMIYAMA HIROAKI, TOMIOKA RYOSUKE, HAYASHI TATSUHIKO, TAKAHASHI SHIGEKI, MAEKAWA MANAMI, SHIBATA KOKICHI, UCHIUMI TATSUYA
• Format: Patent
• Language: English; Japanese
• Published: 21.10.2021
• Subjects: CASTING; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; MAKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; METALLURGY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; POWDER METALLURGY; PRETREATMENT OF RAW MATERIALS; PRODUCTION AND REFINING OF METALS; SEPARATION; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WORKING METALLIC POWDER

To provide a novel production method suitable for reduction of impurities and mass production of high-purity Ir powder of 99.95% purity or more.SOLUTION: A method for producing Ir powder includes a dissolution step, an impurity removal step, a crystal precipitation step, a baking step, and a grinding step. In the dissolution step, an Ir material containing impurities is reacted with an alkali metal salt having oxidizing power at a temperature higher than a predetermined temperature, and then dissolved with an acid to obtain an Ir solution A. The impurity removal step includes: an impurity removing step I comprising adding Fe to the Ir solution A to reduce and precipitate impurities contained in the solution, and removing the precipitate which is reduced and precipitated to obtain an Ir solution B; an impurity removing step II for bringing the Ir solution B into contact with DBC to extract Fe dissolved in the Ir solution B into the DBC, and then oil-water separating the Ir solution to obtain an Ir solution C; an impurity removing step III for bringing the Ir solution C into contact with TBP to extract Ir in the Ir solution C into the TBP, and then oil-water separating the Ir solution to obtain the TBP containing Ir; and an impurity removing step IV for bringing the TBP containing Ir into contact with pure water to extract Ir into the pure water, and then oil-water separating the Ir solution to obtain an Ir solution D.SELECTED DRAWING: None 【課題】不純物量を低減させることができ、純度99.95%以上の高純度Ir粉末の量産に適した新規製造方法を提供する。【解決手段】溶液化工程、不純物除去工程、結晶沈殿化工程、焼成工程、粉砕工程を含むIr粉末の製造方法である。溶液化工程では、不純物を含むIr材を酸化力のあるアルカリ金属塩と所定温度以上の温度で反応させた後、酸で溶液化してIr水溶液Aを得る。不純物除去工程は、Ir水溶液AにFeを加えてその水溶液に含まれている不純物を還元析出させ、その還元析出した沈殿物を除去してIr水溶液Bを得ることを含む不純物除去工程Ｉと、Ir水溶液BとDBCを接触させて、Ir水溶液Bに溶け込んだFeをDBCに抽出させ、次に、油水分離してIr水溶液Cを得る不純物除去工程IIと、Ir水溶液CとTBPを接触させて、Ir水溶液C中のIrをTBPに抽出させ、次に油水分離してIrを含んだTBPを得る不純物除去工程IIIと、Irを含んだTBPを純水と接触させて、Irを純水に抽出させ、次に油水分離してIr水溶液Dを得る不純物除去工程IVを含む。【選択図】なし