PURPOSE: To manufacture the high purity ferrochrome having high Cr content and low content of other impurities by reducing SiO2 in low carbon ferrochrome into Si, thereafter nitriding the low carbon ferrochrome into ferrochrome nitride, pulverizing the ferrochrome nitride, treating it with an acid soln, removing iron therefrom and thereafter executing deoxidization.
CONSTITUTION: Low carbon ferrochrome usually placed on the market is pulverized, is heated in a vacuum heating furnace to reduce the included SiO2 into Si by the reaction of the SiO2 with C. Next, an N2 gas is introduced into the heating furnace, and nitriding treatment is executed to transform the low carbon ferrochrome into ferrochrome nitride. The fine-powdery ferrochrome nitride is charged to a vessel 1 in the shape of fine powder of ≤1mm, to which the water soln. of sulfuric acid is added to form a suspension 2 of the ferrochrome nitride, which is stirred by an impeller 4, and Fe in the ferrochrome nitride is melted by the sulfuric acid and is removed. The ferrochrome nitride is filtered, cleaned and dried, by which the high Cr ferrochrome constituted of 70 to 95wt.% Cr and the balance Fe and having extremely low content of other impurities can be manufactured.
KAWASAKI KIYOSHI
KATO YOSHINORI
