Advanced Alumina Dissolution Modelling

Abstract

Alumina feeding requires optimization for the feed amount, timing, and point feeder locations. The alumina raft formation and dispersion are the essential stages leading to the particles of various sizes travel with the bath flow along anodes in the central channel, in the bath volume beneath the anodes, and gradually dissolving. The raft motion and particles are traced accounting for their inertia, drag in the turbulent flow, the dome-shaped anode bottom shape. Large-scale MHD-driven circulation in the cell is modelled using specific inputs corresponding to real commercial cells of various types. The feed material forming rafts and particles is added periodically, moves with the flow, and gradually dissolves depending on the local turbulence and instantaneous concentration in a location. The newly developed modelling technique is applied to illustrate possible optimization of the feeder locations, the variable mass, and feeding time intervals for possible adjustments suitable for commercial cells.