Figure 14: (a) shear stress vs shear rate (b) viscosity vs shear rate
(Kumar et al, 2022)
Solid concentration and particle diameter
In fig. 15(a) and fig. 15(b) it is seen that as particle size is
decreasing there is increase in yield stress of about 4-5 times
at all solid concentration
also as solid concentration
increased, yield stress increased from 62.5% to 72.5%.
Therefore, it is beneficial to add
fine particles to red mud
slurry as it can increase yield stress and decrease flow.
Figure 15: (a)Yield stress vs solid concentration (b) tailing gradation
(Kumar et al, 2022)
Times
Study of time dependent nature of rheology of tailing is done
because it is necessary to understand and get an idea about
time up to which flow will take place after the failure of dam.
Dependence on time of yield stress and viscosity is shown in
fig 16(a) and fig 16(b). It is also observed that viscosity is
more at longer time in comparison to initial time. Therefore,
at more time flow will reduce.
Figure 16: (a) shear stress vs shear rate (b) shear stress vs viscosity
V.POSSIBLE SOLUTION
Tailings thickening might be a feasible remedy. The idea is
to get rid of the water. The idea is simple: at the completion
of the operation, water is removed from the trash before it is
sent to a dumping place.
The characteristics of the
suspension shift from Newtonian to non-Newtonian when
the moisture is withdrawn. As more water is withdrawn from
the system, the material changes from a thick effluent to a
paste. The difference between thickened tailings and paste is
substantial in terms of rheology.
Figure 17: Paste tailing of iron ore (Boger, 2013)
VI.ADVANTAGES
At plant it increases the water recovery and achievement of
high storage density.
It increases stability as it settles rapidly and once it settles it
does not segregate.
There is very less requirement of large dams and problem of
seepage of water from tailings in groundwater has reduced
drastically and thus minimises
the contamination of
groundwater.
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