Improving the dewatering performance of red sludge with alternative methods in Eti Aluminum Plant in Seydisehir, Konya province, Turkey

increment of usage area of aluminum in the world. One ton of red
sludge on dry bases has come out as a bauxite residue in the course
of 1 ton of alumina and 0.5 tons of aluminum production
respectively. Especially the high liquid ratio significantly reduces
the life of the red sludge dam used as a disposal area. In this study,
alternative techniques have been investigated to improve the
dewatering performance of red sludge in ETI Aluminum Inc. For
this purpose, the vacuum rotary drum filter, decanter centrifuge, and
filter press methods have been searched, and the effects on ETI red
sludge dewatering properties have been obtained. The dewatering
studies have been performed not only at the laboratory scale but
also at the pilot scale to determine the optimum technique and to
achieve the most efficient performance. As a result of dewatering
the 30% solids red sludge with vacuum rotary drum filter, decanter
centrifuge, and press filter methods, solids ratios of 48%, 65%, and
70% were obtained, respectively. While the amount of caustic in the
red sludge produced by the present method was between 1.5 and
3%, the amount of caustic remaining in the cake was reduced to
0.22%, 0.15%, and 0.95%, respectively, by vacuum filtration,
decanter centrifuge, and press filter methods. Thus, reducing the
amount of caustic in the red sludge has reduced its negative impact
on the environment, and a significant amount of caustic has been
recovered.