PRODUCTION OF HIGH-PURITY FERROBORON

摘要

PURPOSE:To enable production of Fe-B contg. less impurities such as Al, Ti and of low carbon in the stage of producing Fe-B in an electric furnace by forming first a hardly meltable material in the furnace then detecting the point of the time when said material is formed and the amt. thereof and changing a reducing agent. CONSTITUTION:A B source such as B2O3, H3BO3 or the like and an Fe source and Si source such as Fe-Si or the like are mixed in an electric furnace 8 provided with an electrode 6 and further a reducing agent effecting weak reduction reaction such as coke or the like is added thereto as a rueduing agent for B2O3 and H3BO3. Electricity is conducted to these materials through the electrode 6 to form a hardly meltable material layer 20 consisting mainly of C and consisting of the reduced B and the carbide thereof. The formation of such hardly meltable material layer is detected by detecting the higher harmonic voltage generated between the electrode 6 and the bottom 8A of the electric furnace by a higher harmonic frequency analyzer 26 and at the same time the amt. thereof is estimated from the temp. detected by a temp. detector 18 embedded in the refractories 18 of the furnace bottom. The reducing agent is changed with charcoal or the like having excellent reactivity at the point of the time when the temp. decreases and when the crest of the higher harmonic component increases, by which the low carbon Fe-B 12 contg. less Al and Ti and having high purity is produced.