{"title":"Intensification of Opening a Thrust Alloy Based on Platinum and Rhodium","authors":"A. V. Egoshina, G. B. Slepchenko","doi":"10.1134/s0020168524700110","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Alloys based on platinum group metals have high chemical resistance, which causes a number of difficulties when dissolving them. Currently, among hydrometallurgical methods, dissolution in aqua regia is one of the most effective methods for opening corrosion-resistant alloys. The main disadvantage of this method is the release of toxic gases such as nitrosyl chloride and nitrogen oxides. To reduce the volume of released gases without reducing the oxidation-reduction potential (ORP) of the system, a method for dissolving a Pt–Rh alloy in HCl–HNO<sub>3</sub> with dosed addition of HNO<sub>3</sub> at a given value of the redox potential of the system is proposed in this study. The system potential chosen on the basis of the potentials of the HNO<sub>3</sub>–HCl–Pt and HNO<sub>3</sub>–HCl–Rh systems is 0.85 and 0.9 V. The influence of dispersion and defectiveness of the Pt–Rh alloy on its dissolution indices is also investigated. As a result, it is shown that the dissolution of the Pt–Rh alloy with a rhodium content of 15% in HCl–HNO<sub>3</sub> at a constant ORP value of 0.9 V compared to the use of classical mixture (HCl : HNO<sub>3</sub> = 1 : 3 (vol)) decreases the nitric acid consumption by 40%, reduces the process time, and increases the recovery factor as for platinum, and for rhodium, and also reduces the volume of released nitrogen oxides by half (theoretical calculation). It is established that the process of mechanical activation of the alloy reduces the dissolution time and leads to almost quantitative dissolution of the sample.</p>","PeriodicalId":585,"journal":{"name":"Inorganic Materials","volume":"253 1","pages":""},"PeriodicalIF":0.9000,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Inorganic Materials","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1134/s0020168524700110","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Alloys based on platinum group metals have high chemical resistance, which causes a number of difficulties when dissolving them. Currently, among hydrometallurgical methods, dissolution in aqua regia is one of the most effective methods for opening corrosion-resistant alloys. The main disadvantage of this method is the release of toxic gases such as nitrosyl chloride and nitrogen oxides. To reduce the volume of released gases without reducing the oxidation-reduction potential (ORP) of the system, a method for dissolving a Pt–Rh alloy in HCl–HNO3 with dosed addition of HNO3 at a given value of the redox potential of the system is proposed in this study. The system potential chosen on the basis of the potentials of the HNO3–HCl–Pt and HNO3–HCl–Rh systems is 0.85 and 0.9 V. The influence of dispersion and defectiveness of the Pt–Rh alloy on its dissolution indices is also investigated. As a result, it is shown that the dissolution of the Pt–Rh alloy with a rhodium content of 15% in HCl–HNO3 at a constant ORP value of 0.9 V compared to the use of classical mixture (HCl : HNO3 = 1 : 3 (vol)) decreases the nitric acid consumption by 40%, reduces the process time, and increases the recovery factor as for platinum, and for rhodium, and also reduces the volume of released nitrogen oxides by half (theoretical calculation). It is established that the process of mechanical activation of the alloy reduces the dissolution time and leads to almost quantitative dissolution of the sample.
期刊介绍：
Inorganic Materials is a journal that publishes reviews and original articles devoted to chemistry, physics, and applications of various inorganic materials including high-purity substances and materials. The journal discusses phase equilibria, including P–T–X diagrams, and the fundamentals of inorganic materials science, which determines preparatory conditions for compounds of various compositions with specified deviations from stoichiometry. Inorganic Materials is a multidisciplinary journal covering all classes of inorganic materials. The journal welcomes manuscripts from all countries in the English or Russian language.
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