Tantalum Recycling by Solvent Extraction: Chloride Is Better than Fluoride

The recycling of tantalum (Ta) is becoming increasingly important due to the criticality of its supply from a conflict mineral. It is used extensively in modern electronics, such as in capacitors, and so electronic waste is a potentially valuable secondary source of this metal. However, the recyclin...

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Bibliographic Details
Published inMetals (Basel ) Vol. 10; no. 3; p. 346
Main Authors Kinsman, Luke M. M., Crevecoeur, Rosa A. M., Singh-Morgan, Amrita, Ngwenya, Bryne T., Morrison, Carole A., Love, Jason B.
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.03.2020
Subjects
Aqueous solutions
chemical separation
Chloride
Chlorides
Electronic waste
Fluorides
Halides
Ions
Leaching
Reagents
Recycling
Solvent extraction
Solvent extraction processes
Solvents
Tantalum
weee
United Kingdom > UK
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Summary:The recycling of tantalum (Ta) is becoming increasingly important due to the criticality of its supply from a conflict mineral. It is used extensively in modern electronics, such as in capacitors, and so electronic waste is a potentially valuable secondary source of this metal. However, the recycling of Ta is difficult, not least because of the challenges of its leaching and subsequent separation from other metals. In this work, we show that Ta(V) halides, such as TaCl5 and TaF5, which can potentially be accessed from Ta metal upon acid halide leaching, can be recovered by solvent extraction using a simple primary amide reagent. The need for high halide concentrations in the aqueous phase implies the formation of the hexahalide salts [TaX6]− (X = F, Cl) and that an anion-swing mechanism operates. While extraction of the fluorides is poor (up to 45%), excellent extraction under chloride conditions is found (>99%) and presents an alternative route to Ta recycling.
ISSN:2075-4701
2075-4701
DOI:10.3390/met10030346