금속열환원법에 의한 희유금속계 니오븀 분말의 제조기술개발

다국어 초록 (Multilingual Abstract)

In this study, niobium powder was made from potassium heptafluoroniobite(K2NbF7) using sodium(Na) as a reductant and KCl, KF as a diluent based on the hunter metallothermic reduction method. The excesses of reductant were varied from 0%, 3%, 5% and 7%. When 7% excess of sodium was used, the un-reacted sodium remained in the reacted product. The niobium powder has been achieved by reducing 50g of K2NbF7 with 5% sodium excess in a charge at a reduction temperature of 850℃. The proportion of fine fraction decreased appreciably and the yield of niobium powder improved from 65% to 85% with the increase of sodium excess. The average particle size of niobium powder is improved from 0.2 microns to 0.3 microns in the 5% excess sodium. The niobium particle size greatly decreased from 0.7um to 0.2um as the amount of diluent increased. However if a higher surface area of powder is required, more diluents need to be used in the said method in order to produce niobium powder. The niobium powder morphology and particle size are very sensitive to a amount of sodium excess. The particle size of niobium powder increased with a increasing amount of sodium excess. When more diluent and sodium are used, the niobium powder will be contaminated with more impurities such as Fe, Cr, Ni so on. The niobium particle size greatly increased as the reduction temperature increased from 710℃ to 800℃. The particle size was fairly uniform, varying from 0.09um to 0.4um 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.

목차 (Table of Contents)

• Ⅰ. 서론 1
• Ⅱ. 이론적 배경 3
• 2.1 니오븀의 개요 및 특성 3
• 2.2 니오븀의 산출광물 및 용도 6
• 2.2.1 산출광물 6
• 2.2.2 용도 8
• 2.3 탄탈륨 및 니오븀 산화물 제조공정 10
• 2.4 추출공정 10
• 2.4.1 염소화반응 10
• 2.4.2 알칼리용융법 13
• 2.4.3 불산침출법 15
• 2.5 니오븀 금속 제조공정 15
• 2.5.1 나트륨(Na) 환원법 15
• 2.5.2 탄소(C) 환원법 17
• 2.5.3 수소 환원법 17
• 2.6 금속열환원 제조공정 17
• 2.6.1 환원반응 기구 17
• 2.6.2 제조방법 19
• Ⅲ. 실험방법 21
• Ⅳ. 결과 및 고찰 24
• 4.1 환원제 첨가량이 니오븀 분말특성에 미치는 영향 24
• 4.2 환원 반응온도가 니오븀 분말특성에 미치는 영향 33
• 4.3 희석제 양의 변화가 니오븀 분말특성에 미치는 영향 46
• Ⅴ. 결론 58
• 참고문헌 60