PCT No. PCT / EP96 / 04764 Sec. 371 Date Sep. 3, 1998 Sec. 102(e) Date Sep. 3, 1998 PCT Filed Nov. 2, 1996 PCT Pub. No. WO97 / 18165 PCT Pub. Date May 22, 1997A process is disclosed for preparing
anhydrous alumina from aluminum
hydroxide which comprises feeding aluminum
hydroxide into a first suspension preheater and partially dehydrating the aluminum
hydroxide with a hot
exhaust gas, transporting the partially dehydrated aluminum hydroxide with said
exhaust gas to a first separating means and separately withdrawing the
exhaust gas and the partially dehydrated aluminum hydroxide, and dividing the partially dehydrated aluminum hydroxide into a first and second partial
stream of solids. The process uses a circulating
fluidized bed comprising a
fluidized bed reactor, a recycle separator connected to the upper portion of said
fluidized bed reactor, and a return line for leading solids from said recycle separator to the lower portion of said fluidized
bed reactor. The second partial
stream of solids is fed into a second suspension preheater and contacted with hot exhaust gas from the recycle separator. The solids and the exhaust gas are transported to a second separating means and an exhaust gas
stream is withdrawn and fed into the first suspension preheater. A dehydrated solids stream is fed into the fluidized
bed reactor and the reactor temperature is adjusted to 850 to 1000 DEG C. A third partial stream of solids is mixed with the first partial stream of solids to form a hot solids mixture. The hot solids mixture is cooled in at least one fluidized
bed cooler and then is fed into the fluidized bed reactor. The hot solids mixture is cooled in at least one fluidized bed cooler.