Magnetic and Electrostatic Separation are two physical separation techniques used to separate materials based on their magnetic or electrical properties. These methods are widely applied in mineral processing, recycling, and material science.
1. Magnetic Separation
Magnetic separation exploits differences in the magnetic susceptibility of materials to separate them using a magnetic field.
# Principle:
– Materials are classified as:
– Ferromagnetic (strongly attracted, e.g., iron, nickel, cobalt)
– Paramagnetic (weakly attracted, e.g., some metal oxides)
– Diamagnetic (repelled, e.g., quartz, bauxite)
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# Types of Magnetic Separators:
– Low-intensity magnets: For ferromagnetic materials (e.g., drum separators).
– High-intensity magnets (HGMS): For weakly paramagnetic minerals.
– Electromagnetic separators: Adjustable field strength for fine separations.
– Eddy current separators: For non-ferrous metals (e.g., aluminum) using repulsion.
# Applications:
– Iron ore beneficiation.
– Removal of tramp iron from coal or food products.
– Recycling (separating me
s from waste).
– Purification of ceramics and glass raw materials.
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2. Electrostatic Separation
Electrostatic separation separates particles based on their electrical conductivity or surface charge differences when exposed to an electric field.
# Principle:
– Materials are charged by:
– Conductive induction (conductors lose charge quickly).
– Frictional charging (triboelectrification).
– A high-voltage electrode attracts or repels particles based on charge.
# Types of Electrostatic Separators:
– Plate/Screen separators: For coarse conductive vs. non-conductive minerals.
– Roll-type separators: Used in mineral sands (e.g., zircon, rutile).
– Triboelectric separators: Based on frictional charging (e.g., plastic recycling).
# Applications:
– Mineral sands processing (ilmenite, monazite).
– Recycling of electronic waste (PCB metal recovery).
– Food industry (removing husks from grains).
– Plastic sorting (PET from PVC).
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Comparison Between Magnetic & Electrostatic Separation
| Feature | Magnetic Separation | Electrostatic Separation |
|——————–|———————|————————–|
| Basis of Separation | Magnetic susceptibility | Electrical conductivity/surface charge |
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