- The Effect of Reduction Temperature on the Characteristic Variation of Niobium Powder During Metallothermic Reduction Process
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Jae-Sik Yoon, Young-Mi Lee, Sun-Ho Hwang, Byung-Il Kim
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J Korean Powder Metall Inst. 2009;16(2):104-109.
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DOI: https://doi.org/10.4150/KPMI.2009.16.2.104
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 Abstract
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- Niobium powder was made from potassium heptafluoroniobite (K_2NbF_7) as the raw material using sodium (Na) as a reducing agent based on the hunter process. The apparatus for the experiment was designed and built specifically for the present study. The niobium particle size greatly increased as the reduction temperature increased from 710°C to 800°C. The particle size was fairly uniform, varying from 0.09µm to 0.4µm depending on the reduction temperatures. The niobium powder morphology and particle size are very sensitive to a reaction temperature in the metallothermic reduction process. The yield of niobium powder increased from 55% to 80% with a increasing a reaction temperature.
- Characteristics of Tantalum Powder Manufactured by the MR and EMR Process
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Hyeoung-Ho Park, Jae-Sik Yoon, In-Sung Bae, Yang-Soo Kim, Dong-Ju Yoon, Dae-Hee Won, Byung-Il Kim
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J Korean Powder Metall Inst. 2007;14(3):173-179.
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DOI: https://doi.org/10.4150/KPMI.2007.14.3.173
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- In the metallothermic reduction (MR) process used to obtain tantalum powder in one batch, it is difficult to control the morphology and location of the tantalum deposits. On the other hand, an electronically mediated reaction (EMR) process is capable of overcoming this difficulty. The effect of using K_2TaF_7 as the raw material and sodium as the reducting agent on the characteristics of tantalum powder are investigated. As the temperature of the reduction varied from 1023K to 1223K, the powder particles obtained with MR were relatively large (sim34µm), while those prepared via EMR were of uniform (13µm). In the MR process, the Ta powder recovery rate increased from 37% to 83% at 1123K in constrat with EMR process.
- Characteristics of Tantalum Powder on the Location of Reductant by MR and EMR Combination Process
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Hyeoung-Ho Park, Jae-Sik Yoon, In-Sung Bae, Yang-Soo Kim, Dong-Ju Yoon, Dae-Hee Won, Byung-Il Kim
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J Korean Powder Metall Inst. 2007;14(3):190-196.
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DOI: https://doi.org/10.4150/KPMI.2007.14.3.190
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Abstract
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- A process known as the MR and EMR combination process is able to overcome the shortcomings of the MR (metallothermic reduction) and EMR (electronically mediated reaction) process. The effects of K_2TaF_7 as the raw material, sodium as the reducing agent and KCl/KF as the diluent on the characteristics of tantalum powder are investigated. In this study, a MR-EMR combination process has been employed to tantalum powder on the location of reductant. The excess of reductant were varied from 25, 50 to 75 wt%. The total charge and external circuit decreases as the amount of reductant increases. The average particle size increases with increasing the amount of reductant.
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