APPLICATION OF PLATE AND FRAME PRESSURE FILTERS TO RED MUD RESIDUE

Cooling, D.J., Myers, L., Bosworth, L.

The extraction of alumina from bauxite produces a residue which is typically stored in secure impoundments adjacent to the alumina refinery. At Alcoa’s Western Australian refineries, the fine fraction of this residue is thickened and deposited across large drying areas, where solar evaporation reduces the water content and increases the strength of the deposited residue. Alcoa has been assessing the viability of plate and frame pressure filtration of red mud residue to enable mechanical stacking of the residue as an alternative to this current method of deposition and evaporative drying of the thickened slurry. This paper outlines some of the development work and an overall assessment of this alternative technology undertaken by Alcoa.