Separation Operations Flashcards
(44 cards)
-separation of ore particles according to their sizes
-separation of ore particles according to a property where valuable mineral particles are different from gangue mineral particles in that property
-separation of ore particles from the mixture of solids and fluids
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Separation Operations
As the ore contains different minerals, the ____ of an ore varies depending on the minerals it contains
Density
Combination of Particles and Space
Bulk Solid (bulk material)
Mixture of water and solid particles
Pulp
when the solid particles are held up in the water and are well dispered throughout
solids float evenly in water
Suspension
Mixture of fine solids (slimes) and water
Slurry
thick pulp (pulp with less quantity of water)
Sludge
ratio of the weight of the water to the weight of the solids in the slurry
Dilution Ratio
The act of settling of solid particles in a fluid medium under the force of gravity
solids settling at the bottom
Sedimentation
Principles of Settling
If the two particles have the same specific gravity?
if same daw silag density?
the larger diameter particle has higher terminal velocity
bigger particles fall faster
Principles of Settling
If two particles have the same diameter?
then the heavier particle has higher terminal velocity
Principles of Settling or Basic Principle of Classification?
The coarser, heavier, and rounder particles settle faster than the finer, lighter, and more angular particles
Max Velocitiy and Resistance
maximum velocity attained by the particle of Vm. Once the particle attains this velocity, it will fall with the same velocity thereafter.
When the acceleration is zero, the particle attains the ____.
Terminal Velocity
Max Velocity and Resistance
the resistance to the motion is due to the shear forces or viscosity of the fluid.
Viscous Resistance
Max Velocity and Resistance
at high velocities, the main resistance is due to the displacement of fluid by the particle.
Turbulent Resistance
in a large volume of fluid, the particle settles by its own specific gravity, size and shape and uninfluenced by the surrounding particles as the particles are not crowded
free settling
when the particles settle in a relatively small volume of fluid, they are crowded in a pulp and are very close to each other. As a result, the settling of a particle is influenced by surrounding during their settling and this collision affects their settling velocities.
hindered settling
if they have the same terminal velocities in the same fluid and in the same fluid of force
equal settling particles
the ratio of the sizes of two particles of different specific gravities
that fall at equal rates.
settling ratio
when the terminal velocities of these two particles are the same and the particles are fine, obeying Strokes’ law of settling,
Free Settling Ratio
where n = 0.5 for fine particles obeying Strokes’ law and n = 1 for coarse
particles obeying Newton’s law. The value of n lies in the range 0.5 – 1 for
particles in the intermediate size range of 100-2000 microns.
General Equation for Free Settling Ratio
the effective density and viscosity of a concentrated suspension are much larger
than those of a clear liquid. The settling medium therefore offers high resistance
and this resistance to fall is mainly due to the turbulence created. Hence
Newton’s law can be used to determine the approximate terminal velocity of the
particles.
hindered settling ratio
- a method of separating mixtures of particles of different sizes,
shapes and specific gravities into two or more products on the basis
of the velocity with which the particles fall through a fluid medium
i.e., settling velocity
classification
Generally, ____ is employed for those particles which are considered too fine to be separated efficiently by screening
classification
