Strong spherical granules of active alumina are prepd. by granulating a mixt. of an aluminium oxide hydrate (opt. preliminary dehydrated and ground) and carbon with addn. of an ammonia soln.; drying the granules; heating them at 250-500 degrees C; and finally calcining at 1000-1200 degrees C. The granulation is carried out with addn. of long-chain aliphatic cpds. and/or clay. The granular alumina can be impregnated with a catalyst soln. and used as a mobile catalytic bed; the mechanical strength and abrasion resistance of the granules is very high. The addn. of the long-chain aliphatic cpds. diminished the width of the particle size spectrum, whilst the ave. size can be adjusted to the reqd. value by known methods. The addn. of clay improves the workability of the mixt. of starting matls., reduces the bulk density of the prod. (by 0.15-0.20 kg/l) and increases its specific surface area (by 30-70 m2/g).
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