금속열환원법에 의한 니오븀 분말제조시 환원제의 영향

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.