| 摘要 |
<p>1404543 Production of alumina in bead form BAYER AG 8 June 1973 [8 June 1972] 27334/73 Heading C1A A process for the treatment of aluminium oxide comprises (a) effecting partial dehydration of aluminium oxide trihydrate by heating it to a temperature of from 350-800‹ C. in from 0À1-1 sec. in a high-turbulence zone of a hot gas stream having a temperature of from 500- 1200‹ C., the hot gas stream entering an axially symmetrical reaction zone tangentially at a rate of flow of from 30-150 m./sec., and the partially dehydrated Al 2 O 3 having the heavily distorted crystalline structure of Chi-Al 2 O 3 , a specific surface (BE7) of >300 m.<SP>2</SP>/g., a residual water content of from 2-15% by wt., and a water absorption capacity at 50% relative humidity of more than 15% (b) grinding the partially dehydrated Al 2 O 3 until the screening residue on a 40 Á screen amounts to <20% (c) adding water and forming the Al 2 O 3 into shaped bodies and (d) drying and actuating the shaped bodies with a dry inert gas at from 200-500‹ C.</p> |
