DIGESTER VESSEL DESIGN

The Ras Al-Khair aluminium complex is a fully integrated aluminium production facility consisting of a 1.8 Million tonne per year alumina refinery. The Ma’aden alumina refinery is adopting a single stream digestion process which couples jacketed pipe unit technology with traditional autoclave digestion technology. The bauxite to be digested has a total available alumina of approximately 50% half of which is boehmitic with a broad particle size distribution, requiring a high digestion temperature and appropriate residence time. A combination of physical modelling and direct steam injection design principles were used to assess residence time distributions of the selected particle sizes of the bauxite. Two types of arrangements of feed slurry geometries were studied. Residence time distribution of solid phase bauxite particles were shown to be sensitive to different slurry inlet configurations.