Metallic tantalum powder is manufactured by reducing tantalum oxide (Ta₂O₅) with magnesium gas at 1,073–1,223 K in a reactor under argon gas. The high thermodynamic stability of magnesium oxide makes the reduction reaction from tantalum oxide into tantalum powder possible. The microstructure after the reduction reaction has the form of a mixture of tantalum and magnesium oxide, and the latter could be entirely eliminated by dissolving in weak hydrochloric acid. The powder size in SEM microstructure for the tantalum powder increases after acid leaching in the range of 50–300 nm, and its internal crystallite sizes are observed to be 11.5 to 24.7 nm with increasing reduction temperatures. Moreover, the optimized reduction temperature is found to be 1,173 K as the minimum oxygen concentration is approximately 1.3 wt.%.

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• A review of tantalum resources and its production
  Xue WEI, Long-gong XIA, Zhi-hong LIU, Le-ru ZHANG, Qi-hou LI
  Transactions of Nonferrous Metals Society of China.2023; 33(10): 3132.     CrossRef
• Valuable metal recovery from waste tantalum capacitors via cryogenic crushing-alkaline calcination-leaching process
  Longgong Xia, Xue Wei, Hongjun Wang, Fengchun Ye, Zhihong Liu
  Journal of Materials Research and Technology.2022; 16: 1637.     CrossRef

In this study, an experiment is performed to recover the Li in Li₂CO₃ phase from the cathode active material NMC (LiNiCoMnO₂) in waste lithium ion batteries. Firstly, carbonation is performed to convert the LiNiO, LiCoO, and Li₂MnO₃ phases within the powder to Li₂CO₃ and NiO, CoO, and MnO. The carbonation for phase separation proceeds at a temperature range of 600°C~800°C in a CO₂ gas (300 cc/min) atmosphere. At 600~700°C, Li₂CO₃ and NiO, CoO, and MnO are not completely separated, while Li and other metallic compounds remain. At 800 °C, we can confirm that LiNiO, LiCoO, and Li₂MnO₃ phases are separated into Li₂CO₃ and NiO, CoO, and MnO phases. After completing the phase separation, by using the solubility difference of Li₂CO₃ and NiO, CoO, and MnO, we set the ratio of solution (distilled water) to powder after carbonation as 30:1. Subsequently, water leaching is carried out. Then, the Li₂CO₃ within the solution melts and concentrates, while NiO, MnO, and CoO phases remain after filtering. Thus, Li₂CO₃ can be recovered.

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• Metals Recovery from Spent Lithium-ion Batteries Cathode Via Hydrogen Reduction-water Leaching-carbothermic or Hydrogen Reduction Process
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  Mining, Metallurgy & Exploration.2024;[Epub]     CrossRef
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  Metals.2023; 13(5): 923.     CrossRef
• Holistic Investigation of the Inert Thermal Treatment of Industrially Shredded NMC 622 Lithium-Ion Batteries and Its Influence on Selective Lithium Recovery by Water Leaching
  Christin Stallmeister, Bernd Friedrich
  Metals.2023; 13(12): 2000.     CrossRef
• Environmentally Friendly Recovery of Lithium from Lithium–Sulfur Batteries
  Lilian Schwich, Bernd Friedrich
  Metals.2022; 12(7): 1108.     CrossRef
• Early-Stage Recovery of Lithium from Tailored Thermal Conditioned Black Mass Part I: Mobilizing Lithium via Supercritical CO2-Carbonation
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  Metals.2021; 11(2): 177.     CrossRef
• Exploring a green route for recycling spent lithium-ion batteries: Revealing and solving deep screening problem
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Titanium carbide (TiC) powders are successfully synthesized by carburization of titanium hydride (TiH₂) powders. The TiH₂ powders with size lower than 45 μm (-325 Mesh) are optimally produced by the hydrogenation process, and are mixed with graphite powder by ball milling. The mixtures are then heat-treated in an Ar atmosphere at 800-1200oC for carburization to occur. It has been experimentally and thermodynamically determined that the dehydrogenation, “TiH₂ = Ti + H₂”, and carburization, “Ti + C = TiC”, occur simultaneously over the reaction temperature range. The unreacted graphite content (free carbon) in each product is precisely measured by acid dissolution and by the filtering method, and it is possible to conclude that the maximal carbon stoichiometry of TiC_0.94 is accomplished at 1200°C.

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• Pre-treatments of initial materials for controlling synthesized TaC characteristics in the SHS process
  Jae Jin Sim, Sang Hoon Choi, Ji Hwan Park, Il Kyu Park, Jae Hong Lim, Kyoung Tae Park
  journal of Korean Powder Metallurgy Institute.2018; 25(3): 251.     CrossRef