Fluidized bed process for producing alumina from aluminum hydroxide

US6015539A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Hans-Werner Schmidt · Bayreuth, DE
• Martin Rahn · Frankfurt am Main, DE
• Werner Stockhausen · Bad Vilbel, DE
• Dietrich Werner · Messel, DE
• Martin Hirsch · Friedrichsdorf, DE

Key dates

• Filing date: Sep 3, 1998
• Grant date: Jan 18, 2000
• Expiry date: Sep 3, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01F7/445
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

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 The solids and the exhaust gas are transported to a second separating means and an exhaust gas stream is withdrawn and fed into the first suspension preheater.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