Consideration of Diluents Selection and Input Amounts of the Hunter Process for Tantalum Production


Tantalum (Ta) is a heavy refractory metal with an atomic weight of 180.95 g/mol, a density of 16.6 g/cm3, and a high melting point of 3017 °C. With its refractory characteristics, it shows excellent chemical and physical stability as well as corrosion and heat resistance at elevated temperatures. The demand for Ta metal and related compounds is increasing with the expansion of the electronics and chemical industries. The Hunter process was proven to be effective in producing Ta powder in 1953. Hunter proposed a method in which potassium heptafluorotantalate (K2TaF7) was reduced by sodium (Na). Thus far, this process has been the primary commercial method to produce Ta powder. In this study, quantitative differences were analyzed for diluent selection. Additionally, consideration was given to changes in the caloric value depending on the input amount of diluents. Finally, the optimum material input and the properties of the prepared Ta were analyzed. Stoichiometric ratios of K2TaF7(1 mol), NaCl (6.2–6.7 mol), Na (5–7 mol) were weighed, to perform a metallothermic reduction reaction. After the reaction, the tantalum powder was recovered and the flush process was carried out. After that, it was dried in a vacuum atmosphere. Physical properties such as oxygen concentration, PSA, ICP-OES, and XRD of powder were conducted to evaluate the characteristics of Ta powder that was finally manufactured.

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This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20195210100070, Upcycling techniques of low grade tantalum scraps by intergrated hydro- and pyro-metallurgical process) and Korea Evaluation Institute of Industrial Technology (KEIT) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea(No. 20010585, 3 N grade smelting technology for toxic salts and fluoride gas for Ti-metallic metal materialization).

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Correspondence to Seok-Jun Seo or Kyoung-Tae Park.

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Sim, JJ., Choi, SH., Lee, YK. et al. Consideration of Diluents Selection and Input Amounts of the Hunter Process for Tantalum Production. Met. Mater. Int. (2021).

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  • Tantalum
  • Hunter process
  • Metallothermic reduction
  • Powder
  • Diluent