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탈수소화 분위기가 탄탈륨 분말 수소농도에 미치는 영향 연구
이지은(Ji-eun Lee),윤진호(Jin-Ho Yoon),이찬기(Chan Gi Lee) 강원대학교 산업기술연구소 2021 産業技術硏究 Vol.41 No.1
Hydride-dehydride process for efficient recycling of tantalum (Ta) is used for manufacturer of Ta powder. In case of metal powder, Impurities as like nitride, oxygen, hydrogen is decreased of physical properties. For manufacture of Ta powder, control of theses impurities is important. In this study, to decreased of impurities on Ta powder using HDH process optimize dehydride condition. Dehydration behavior of Ta is depended on temperature, time, and atmosphere. Phase transition of Ta hydride is analyzed by X-ray diffraction (XRD). Concentration of hydrogen is decreased with temperature increased. At high temperature, concentration of hydrogen in Ta is similar according to time increased. Size and morphology of powder is not observed after dehydride. Ta powder, which is less than 20 um, concentration of hydrogen under 800 ppm is obtain.
이승영 ( Seung Young Lee ),이상일 ( Sang Il Lee ),원창환 ( Chang Whan Won ) 대한금속재료학회 ( 구 대한금속학회 ) 2009 대한금속·재료학회지 Vol.47 No.6
The purpose of this study is to make the tantalum powder for solid electrolyte capacitor with SHS (self-propagating high-temperature synthesis) process. Raw materials for manufacturing Ta powder were used Ta2O5, Mg and NaCl. While progressing SHS process, Ta2O5 powder was reduced by Mg powder. The combustion temperature and velocity were easily controled by the varying mole ratio of NaCl, Mg and initial reaction pressure. In the case of only using NaCl as an inorganic agent, the shape is unagglomerated and has high surface area. whereas we were given the powder which has good net structure by the addition of excessive Mg as a diluent. (Received January 13, 2009)
Consideration of Diluents Selection and Input Amounts of the Hunter Process for Tantalum Production
Jae‑Jin Sim,Sang‑Hoon Choi,Yong‑Kwan Lee,Sung Gue Heo,Taek‑Soo Kim,Seok‑Jun Seo,Kyoung‑Tae Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7
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 meltingpoint of 3017 °C. With its refractory characteristics, it shows excellent chemical and physical stability as well as corrosionand heat resistance at elevated temperatures. The demand for Ta metal and related compounds is increasing with the expansionof the electronics and chemical industries. The Hunter process was proven to be effective in producing Ta powder in1953. 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 wereanalyzed for diluent selection. Additionally, consideration was given to changes in the caloric value depending on the inputamount of diluents. Finally, the optimum material input and the properties of the prepared Ta were analyzed. Stoichiometricratios 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 avacuum atmosphere. Physical properties such as oxygen concentration, PSA, ICP-OES, and XRD of powder were conductedto evaluate the characteristics of Ta powder that was finally manufactured.
MR-EMR 복합공정에 의한 탄탈륨분말의 제조시 과잉첨가 환원제 양에 따른 분말의 특성
배인성,윤재식,박형호,김병일,이현우,김낙찬,설경원 한국분말야금학회 2004 한국분말재료학회지 (KPMI) Vol.11 No.4
In this study, tantalum powder has been producted by MR-EMR combination process. MR-EMR combination process is a method that is able to improve demerits of MR(metallothermic reduction) and EMR(electronically mediated reaction) process. This study examined the characteristics of powder with the amount of reductant excess using $K_2$TaF$_{7}$ as feed materials, Na as a reductant and KCl/KF as a diluent. In addition, this study examined acid treatment that affect the high purification of powder. The impurities contained in powder was removed in various conditions of acid treatment. The total charge passed through external circuit and average particle size(FSSS) were increased with increasing amount of sodium excess. The proportion of fine particle(-325mesh) was decreased with increasing amount of sodium excess. The yield was improved from 70% to 76% with increasing amount of sodium excess. Considering the impurities, charge, morphology, particle size and yield, an amount of sodium excess of 10wt% were found to be optimum conditions for MR-EMR combination process.s.
탄탈륨 산화물의 마그네슘 가스환원에 의한 탄탈륨 금속분말 제조
이동원,Lee, Dong-Won 한국분말야금학회 2018 한국분말재료학회지 (KPMI) Vol.25 No.5
Metallic tantalum powder is manufactured by reducing tantalum oxide ($Ta_2O_5$) 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.%.
도전체 매개반응(EMR)법에 의한 미세 Ta 분말 제조
박일,이철로,이오연,Park Il,Lee Chuel Ro,Lee Oh Yeon 한국재료학회 2004 한국재료학회지 Vol.14 No.10
Production of fine tantalum powder by calciothermic reduction of tantalum oxides ($Ta_{2}O_5$) pellet through an electronically mediated reaction (EMR) has been investigated. $Ta_{2}O_5$ pellet feed and reductant calcium-nickel (Ca-Ni) alloy were charged into electronically isolated locations in a molten $CaCl_2$ bath. The current flow through an external path between the feed (cathode) and reductant (anode) locations was monitored. The current approximately 4.7A was measured during the reaction in the external circuit connecting cathode and anode location. Tantalum powder with approximately 99 $mass\%$ purity was readily obtained after each experiment. Tantalum powder by EMR using $Ta_{2}O_5$ pellet feed was fine compared with that of metal powder by metallothermic reduction and EMR using $Ta_{2}O_5$ powder feed.
윤재식,박형호,배인성,이상백,윤동주,김병일,Yun, Jae-Sik,Park, Hyeong-Ho,Bae, In-Seong,Lee, Sang-Baek,Yun, Dong-Ju,Kim, Byeong-Il 한국재료학회 2001 한국재료학회지 Vol.11 No.12
Purity tantalum powder has been produced by sodium reduction of potassium tantalum fluoride($K_2TaF_7$)in a stainless steel bomb. The influence of experimental variable, such as excess of reductant and temperature of reduction on the yield and quality of the Ta powder has been studied. The excesses of reductant were varied from -20%, -10%, 0%, 5%, 10%, 20%. When -20% excess of sodium was used, the un-reacted sodium remained in the reacted product. The yield of 81% of Ta powder has been achieved by reducing 50g of$K_TaF_7$with 5% sodium in excess of stoichiometric amount in presence of 16.8g of sodium chloride in the charge at a reduction temperature of$905{\circ}C$. The proportion of fine fraction(~325mesh) decreased appreciably with the increase of sodium excess, and the yield of tantalum powder improved from 65% to 94%. The average particle size of Ta Powder is improved from 3 microns to 4 microns in the 5% excess sodium.
MR-EMR 복합제조공정에서 환원제 위치가 탄탈륨 분말 특성에 미치는 영향
박형호,윤재식,배인성,김양수,윤동주,원대희,김병일,Park, Hyeoung-Ho,Yoon, Jae-Sik,Bae, In-Sung,Kim, Yang-Soo,Yoon, Dong-Ju,Won, Dae-Hee,Kim, Byung-Il 한국분말야금학회 2007 한국분말재료학회지 (KPMI) Vol.14 No.3
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.
박형호,윤재식,배인성,김양수,윤동주,원대희,김병일,Park, Hyeoung-Ho,Yoon, Jae-Sik,Bae, In-Sung,Kim, Yang-Soo,Yoon, Dong-Ju,Won, Dae-Hee,Kim, Byung-Il 한국분말야금학회 2007 한국분말재료학회지 (KPMI) Vol.14 No.3
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 $({\sim}34{\mu}m)$, while those prepared via EMR were of uniform $(13{\mu}m)$. In the MR process, the Ta powder recovery rate increased from 37% to 83% at 1123K in constrat with EMR process.
MR-EMR 복합공정에 의한 탄탈륨분말의 제조시 온도변화에 따른 분말의 특성
배인성,윤재식,박형호,윤동주,이민호,설경원,김병일 한국분말야금학회 2003 한국분말재료학회지 (KPMI) Vol.10 No.6
In the conventional metallothermic reduction (MR) process for obtaining tantalum powder in batch-type operation. it is difficult to control morphology and location of deposits. On the other hand, a electronically mediated reaction (EMR) process is capable to overcome these difficulties and has a merit of continuous process, but it has the defect that the reduction yield is poor. MR-EMR combination process is a method that is able to overcome demerits of MR and EMR process. In this study, a MR-EMR combination process has been applied to the production of tantalum powder by sodium reduction of $K_2$TaF$_{7}$. The total charge passed through external circuit and average particle size (FSSS) were increased with increasing reduction temperature. The proportion of fine particle (-325 mesh) was decreased with increasing reduction temperature. The yield was improved from 65% to 74% with increasing reduction temperature. Considering the charge, impurities, morphology, particle size and yield, an reduction temperature of 1,123 K was found to be optimum temperature for MR-EMR combination process.