Density separation of materials by using magnetic fluids
The magnetic fluid is a colloidal suspension of magnetite in kerosene, prepared by a low-cost process. Separation is accomplished in an open trough filled with magnetic fluid. A magnetic field is established in the fluid, by energizing an electromagnet having poles on each side of the trough. Due to the design of the magnet poles and air gaps, the magnetic field is strongest at the bottom, about 10,000 oersteds, and uniformly decreases in strength to about 2000 oersteds at the top of the fluid. Therefore, the magnetic field gradient increases with depth. The magnetic force attracts the entire separation medium (magnetic fluid) creating a reaction force of equal magnitude and acting in the opposite direction. This reaction created within a magnetic fluid/magnetic field combination is called a magnetic levitation force. It increases with the field strength. In this case because the magnetic field is strongest at the bottom of the trough, the magnetic levitation force will quickly float lighter material while heavier material sinks. The separated materials are removed from the trough by two conveyor belts. Sink materials are collected near the bottom while float materials are collected near the surface. Changing the magnetic field strength, by changing the current through the electromagnet and/or the magnetic strength of the magnetic fluid allows wide variations.
- OSTI ID:
- 5424644
- Journal Information:
- Bur. Mines Technol. News; (United States), Vol. 76
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COAL PREPARATION
MAGNETIC SEPARATORS
KEROSENE
MAGNETITE
CHALCOGENIDES
COMMINUTION
CONCENTRATORS
FUELS
IRON COMPOUNDS
IRON ORES
IRON OXIDES
LIQUID FUELS
MINERALS
ORES
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PETROLEUM PRODUCTS
TRANSITION ELEMENT COMPOUNDS
013000* - Coal
Lignite
& Peat- Transport
Handling
& Storage