Magnetic & Electrostatic Separation

Question 1

utilizes the force of magnetic field to produce different movement of
mineral particles through a magnetic field

Answer 1

Magnetic Separation

Question 2

Purposes:
• Separation of magnetic valuable minerals from gangue
• Removal of tramp metals

Answer 2

Magnetic Separation

Question 3

What are the 3 classifications of magnetic attraction?

Answer 3

Diamagnetics, Paramagnetics, Ferromagnetics,

Question 4

nonmagnetic materials,
which are repelled along the lines of
magnetic force to a point where the field
intensity is small. The forces involved
here are very small and they cannot be
concentrated magnetically.

Answer 4

Diamagentics

Question 5

copper, mercury, gold, bismuth

Answer 5

Diamagnetics

Question 6

weakly magnetic
materials, which are attracted along the
lines of magnetic force to points of
greater field intensity. They can be
concentrated in high-intensity magnetic
separators

Answer 6

Paramagnetics

Question 7

ilmenite (FeTiO3), rutile (TiO2),
siderite (FeCO3), pyrrhotite (FeS), and
hematite (Fe2O3)

Answer 7

Paramagnetics

Question 8

strongly magnetic
minerals, which have very high
susceptibility to magnetic forces and
retain some magnetism when removed
from the field (remanence). They can be
concentrated in low-intensity magnetic
separators.

Answer 8

Ferromagnetics

Question 9

magnetite (Fe3O4), cobalt, nickel

Answer 9

Ferromagnetics

Question 10

– the prime requirement is the provision of a

high-intensity field in which there is a steep field strength gradient

Answer 10

Magnetic Field Gradient

Question 11

– the intensity must be regulated in order to deal with various types of material

Answer 11

Magnetic Field Intensity

Question 12

What are the two types of magnetic separators?

Answer 12

Low- intensity & High- intensity

Question 13

– for ferromagnetic and highly paramagnetic minerals

Answer 13

Low- Intensity

Question 14

– for very weakly paramagnetic minerals

Answer 14

High- Intensity

Question 15

What are the 3 methods under low-intensity magnetic separators?

Answer 15

magnetic pulley, drum separator, cross- belt separator

Question 16

a LIMS that were used for tramp iron removal

Answer 16

Magnetic Pulley

Question 17

• separation occurs by the “pick-up”

principle

Answer 17

Drum Separator

Question 18

Drum separator:

used for concentrating coarse sands which are strongly magnetic (cobbing)

Answer 18

Dry LIMS

Question 19

Drum separator:

used for recycling and
cleaning magnetic media in DMS and
processing of ferromagnetic sands

Answer 19

Wet LIMS

Question 20

What are the three types of Drum Separators?

Answer 20

concurrent, counter- current, counter- rotation

Question 21

What are the 2 methods for High- Intensity Magnetic Separators?

Answer 21

induced roll magnetic separator & wet high- intensity magnetic separator (WHIMS)

Question 22

• widely used to treat beach sands,
  wolframite and tin ores, glass sands,
  phosphate rock and weakly magnetic
  iron ores

Answer 22

Induced Roll Magnetic Separator

Question 23

• widely used to concentrate low-grade iron ores containing hematite

Answer 23

Wet High-Intensity Magnetic Separator (WHIMS)

Question 24

• uses difference in electrical conductivities of ore feed for separation
• limited to dry, fine particle size, small capacity operation

Answer 24

Electrostatic Separation

Question 25

high surface charge

Answer 25

Insulators

Question 26

no charging effect

Answer 26

Conductors

Question 27

What are the different charging mechanisms of electrostatic separation?

Answer 27

Ion Bombardment, Conductive Induction, Triboelectric Charging

Question 28

– a high voltage is applied between 2 electrodes so that the gas near the electrodes ionizes and forms a corona discharge, a continuous flow of gaseous ions

Answer 28

Ion Bombardment

Question 29

– polarization of a mineral particle occurs | upon exposure to an electric field

Answer 29

Conductive Induction

Question 30

– an uncharged particle develops an opposite charge relative to the electrode at its surface closest to the electrode, and a corresponding like charge to the electrode on the particle surface furthest from the electrode

Answer 30

Polarization

Question 31

``` – contact electrification – two materials of dissimilar electrical properties exchange electrons upon coming into contact with one another ```

Answer 31

Triboelectric Charging

Question 32

What are the two mechanisms of separation?

Answer 32

lifting effect & pinning effect

Question 33

the attraction of particles carrying one kind of charge toward an electrode of the opposite charge. Particles are lifted from the separating surface toward the electrode.

Answer 33

Lifting Effect

Question 34

non-conducting mineral particles, having received a surface charge from the electrode, retain this charge and are pinned to the oppositely charged separator surface by positive-negative attraction.

Answer 34

Pinning Effect