To produce low-oxygen silicon granules capable of efficiently producing silicon nitride having a high α-silicon nitride content by direct nitriding and suitable for use as starting material for direct nitriding and to produce silicon nitride using the low-oxygen silicon granules.
An org. binder is added to silicon powder of 4-10μm average particle diameter by 0.3-3wt.% of the amt. of the powder and they are mixed and granulated. The resultant granules are heated at 1,320-1,400°C for 0.5-5hr while circulating an inert gas other than nitrogen to obtain the objective low- oxygen silicon granules having ≥0.5m2/g specific surface area, ≤0.4wt.% oxygen content and <1wt.% carbon content. These silicon granules are nitrided in an atmosphere of nitrogen contg. hydrogen to produce the objective silicon nitride.
WATANABE MAKI
KONYA YOSHIHARU
FUKUHIRA MASANORI
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