Download - Separator Efficiency Calculations
By Dr Y C Naidu
Types of classsificationBasis of Volume ie geometric dimension-
screeningBasis of Mass ie materila properties
Cyclone SeparatorsAir Separators
Principles of SeparationA particle is subjected to three sets of
forces Fd-Force exerted by airFc- Centrifugal forceFg- Force of gravityIf Fd> Fc and Fg, particle air borneFg prevails particle sinkFc prevails particle flung outward of
separator
Particle Size DistributionCumulative distribution curve
On different sieves/micron sizes, the cumulative passing % is plotted.
Independent particle size distribution curve
Size Distribution Curve
Particle Size Distribution
Classification A= F+GA- Classifier feed rate, tphF-Fines output, tphG- Tailing outputa,f,g- proportion of undersize in A,F,and G in
%∆a, ∆f, ∆g – Proportion of particular size
fraction of A,F, G in %
Equations- SeparatorsA.a = F.f+G.gA. ∆a = F. ∆f+G. ∆gVf- % of output finesVg- % of output tailingsP- Precipitation efficiencyµ- recycle ratio
Fines OutputVf =F/Ax100
Vg=G/Ax100
Vf+Vg =100
Calculated from particle size
Vf= a-g x 100 f-g Vg = f-a x 100 f-g
Recycle ratio = A/F = (f-g)/(a-g)
Precipitation Efficiency = (Fxf)/(Axa)x100= Vfxf/ax100
SelectivityIt is characterized by what % of given
particle size in classifier feed is discharged in tailings
T – (Gxdg)/(A.da) x100 = Vg x dg/da
Cut SizeParticle size dt of which half the particles are
discharged in fines and half in tailings.If sharpness of separation poor, more than
50% of even finest particles may end up in tailings, so no definite cut size exists