Article Number 200110, November 2001

IMPROVEMENTS IN THE DESIGN AND OPERATION OF ALUMINA FLASH CALCINERS
JENKINS Barrie* and BERTRAND Christine**

* 349, Desborough Avenue, High Wycombe, Bucks., HP11 2TH. U.K.
Click here to send an e-mail message (IFRF Exchange member).

** CINAR Ltd., 11, Elvaston Place, South Kensington, LONDON SW7 5QG. U.K.
christine@cinar.co.uk

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ABSTRACT:

Alumina hydrate produced by the Bayer-Hall-Heroult process is calcined at ~1100°C in either a rotary kiln, or a stationary vertical flash or fluid bed calciner. The latter calcination process is more thermally efficient than the rotary kiln, but the difficult nature of the process environment (pressurised, high temperature combustion in an abrasive dust laden atmosphere) makes any investigation of the furnace operation very difficult. This paper describes how physical and mathematical models have been developed to enable operators and designers to understand the process dynamics. A number of modelling techniques are used to fully simulate the system, including physical modelling of the aerodynamics and mixing, zero and one dimensional heat transfer models, and CFD models of the two-phase material flows. These models have been validated against unique plant measurements using special probe techniques. The resulting models have been used to improve existing designs, and to develop a new generation of larger, more efficient flash calcination units.

Key Words: Modelling, Calcination, Alumina.

Corresponding Author:

JENKINS Barrie
349, Desborough Avenue,
High Wycombe,
Bucks., HP11 2TH. U.K.

Tel.: + 44 1494 521 001

E-mail: Click here to send an e-mail message (IFRF Exchange member).