Importance

Loading Importance Indicators...

Abstract

A 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 The solids and the exhaust gas are transported to a second separating means and an exhaust gas stream is withdrawn and fed into the first suspension preheater.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.degree. 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.

Loading the Abstract Image...

First Claim