Biopolymer use as a sand filter aid

摘要

In the Bayer process for producing alumina from bauxite of the type wherein the bauxite is added to a caustic solution to produce a soluble aluminate solution and an insoluble red mud fraction which is then subjected to one or more separation steps to produce a thickener overflow which is then subjected to a Sand Filter to polish the thickener overflow the improvement which comprises treating the thickener overflow with a solids removal efficiency improving amount of a biopolymer.