Settling Characteristics of Qal Red Mud

D D De e ep p pa a ar r rt t tm m me e en n nt t t O O Of f f C C Ch h he e em m mi i ic c ca a al l l E E En n ng g gi i in n ne e ee e er r ri i in n ng g g b b by y y T T To o ob b by y y M M Ma a ar r rs s sh h h S S Su u up p pe e er r rv v vi i is s so o or r r: : : D D Dr r r T T To o on n ny y y H H Ho o ow w we e es s s S S Su u ub b bm m mi i it t tt t te e ed d d: : : O O Oc c ct t to o ob b be e SUMMARY Red mud is a waste product of Bayer process. The composition of the red mud is mostly oxides of iron, titanium, soda-alumina-silicate compounds, unreacted quartz, and other insolubles in the bauxite. It must be removed from the pregnant caustic liquor prior to precipitation or impurities will be present in the final product. The removal is achieved in gravity settling tanks under flocculated conditions. The size of these settling tanks is determined by the rate at which the red mud settles. The initial aim of this thesis was to develop a simple, reproducible test that could be used to assess the performance of flocculents in aiding settling. However, due to equipment constraints, the aim was changed to developing an understanding of the settling characteristics of the mud. This was investigated using a settling vessel equipped with light sensors. Some difficulties were experienced owing to the fact that the intensity of the light was not sufficient to obtain readings at all but very low concentrations. Hence, the settling characteristics of the red mud slurry could not be obtained. Other deficiencies in the experimental process were identified as the method of flocculent preparation, the dispersion of flocculent in the slurry and influence of wall effects on the settling of flocculated particles. This thesis did not achieve the aim that it set out to, but it is the opinion of the …