A DISCUSSION

ON

MAGNETIC SEPARATION

By :- SHISHIR VIKRANT (495/08)

& RAJESH PASWAN (290/08)

INTRODUCTION

# Magnetic separation is a process in which magnetically susceptible material is extracted from a mixture using a magnetic force.

# Since 19th century magnetic separation processes have been used to concentrate and separate minerals.

INTRODUCTION

# By combining the different forces of magnets with gravitational or frictional forces a separation of mineral particle is possible. Two or more products are obtained depending on their commercial value, these products are concentrates, middlings, or tailings. # Ferromagnetism, paramagnetism and diamagnetism are the three important properties of the minerals which is used for Magnetic separation.

APPLICATION OF MAGNETISM AS SEPARATOR

Basically Magnetism is used for five distinct type of separation :

1.For the removal of tramp iron in coarse and intermediate- crushing circuits, as a protection to the crushing machinery.2.For the concentration of magnetite ores.3.For the concentration of iron ore other than magnetite, after preliminary conversion of iron minerals to artificial magnetite by suitable Roasting.

4. For the removal of small quantities of iron ore minerals from Ceramic raw materials.

5. For the concentration of slightly Paramagnetic minerals such as those of Manganese, tungsten, chromium, tin, zinc, titanium, etc.

ELEMENTS OF DESIGN OF MAGNETIC SEPARATORS

1.Production of suitably converging magnetic field.2.Even feeding of ore particles as a stream or sheet.3.Control of speed of passage of ore through the magnetic field.4.Avoidance and / or correction of occlusion or non magnetic material between or within magnetic flux.5.Provision of suitable means for disposing of separated products.6.Provision for production of a middling.7.Elimination or reduction to a minimum of moving (wearing ) parts.

CLASSIFICATION OF MAGNETIC SEPARATOR

It can be classified according to the medium in which the separation is made, the mode of the presentation of the feed, the mode of disposal of the products, & whether the magnets are stationary or moving.

IMPORTANT TYPES OF MAGNETIC SEPARATOR

1.EDISON SEPARATOR2.BALL NORTON SEPARATOR3.MAGNETIC DRUM SEPARATOR4.ROLLAR TYPE SEPATOR5.GRAVITY FEED MAGNETIC SEPARATOR6.MAGNETIC COOLENT SEPARATOR7.WET DRUM SEPRATOR

EDISON SEPARATOR

Edison separator consists of a bar magnet . The ore as thin streams falls in front of the poles, susceptible particles being deflected inwards & nonsusceptible particles continuing to fall undeflected. This separator was not wholly successful because of inability of control flow of solid in a thin sheet, & because of lack of control over the speed of the falling particles.

Ball Norton SeparatorUnlike most magnetic separators which are used to remove relatively small amounts of metal, the Ball Norton Separator is designed to handle large amounts of ferrous material - removing other undesirable elements. A unique combination of alternating magnetic poles and vibratory conveying works to clean the magnetic material. Applications include foundry shot, crushed borings, slag and magnetic ores.

MAGNETIC DRUM SEPARATOR

Magnetic drum separators are important magnetic separators that removes ferrous metal from dry bulk products in free-flowing processing systems. They are self cleaning unit consisting of drums and housing normally of stainless steel. The magnets used by the magnetic drum separators are either ceramic magnets or rare earth magnets. The magnetic drum separators are available both in single or double drum configuration.

How it Works?The processing materials enters the top of the magnetic drum separator and flows across the surface of the drum. The rotatory drum in the magnetic field captures the ferrous tramps whereas non ferrous falls free from the drum into the cleaned material flow. As the drum rotates, the ferrous metal so captured is carried past the diverter and released outside of the magnetic field.Types

Magnetic drum separators are of different types like: •Electro drum separators •Wet drum separators Double drum separators

ApplicationsThe magnetic drum separator is ideal for separating iron particles from granules & powders It is widely used in the following industries: •Glass•Ceramic •Chemical •Fertilizer •Plastic •Food industry •Iron and steel slag treatment •Reduced pyrite ash separation •Calcined ilmenite production Metal powder production

How it Works? The material is discharge on the belt by the feeder. The magnetic roll is enveloped by the conveyor. The para and ferro magnetic ingredients remains stuck to the belt whereas non magnetic ingredients passes freely at the end of the conveyor.

Roller type magnetic separator is meant to separate ferrous contaminants from the flimsy magnetized dry granular metallic and nonmetallic materials. Roller type magnetic separator has wide application in industries and mineral technology. The separator uses high powered rare earth magnets with very low dimensional tolerance. The other components of the machine are conveyor and vibratory feeder. The magnetic rolls are available in different widths and magnetic strength

ApplicationsRoller type magnetic separator finds applications in the following areas like: •Glass industries•Abrasive refractory •Quartz cleaning •Upgrading of graphite •Recovery of metals from slag removal of ferro silicates •Chemical industries

Gravity feed magnets separates ferrous tramp metal through gravity system. These magnets are constructed out of welded stainless steel and are available in stainless steel structure. The gravity magnet comes in different shapes and sizes and are ideal for narrow chute applications. Gravity feed magnets are normally used in vertical flow system.

ApplicationsGravity magnetic separators have different industrial and commercial usage. They are applied in industries like: •Food industry •Chemical industry •Grain processing industries Pharmaceutical industries

MAGNETIC COOLENT SEPARATOR

Magnetic coolant separator is a device which cleans the coolant liquid of very fine ferrous particles. It removes the iron chips from the milling or grinding liquid. It is light and compact structure having strong magnetic power which can remove very fine ferrous particles. For precise grinding operations uninterrupted flow of oil is must. The coolant magnetic separator ensures the uninterrupted flow of the liquid.

WET DRUM SEPARATOR

Features Wet drum magnets have high magnetic recovery and discharge. The feed slurries recover the magnetics. Available in single or multiple drum applications. Recover magnetic solids in as clean a magnetic concentrate as possible . Permanent magnet assembly eliminates coil burn-outs . The magnet / pole elements are bolted to a mild steel shaft. The drum is made from thick stainless steel for long service life. Wet drum separators are available in different configuration like single drum,double drum and multiple drum. In double drum two separators are arranged back to back with a common feed back.

Applications

Glass industry Chemical industry Plastic industry Mining industry Food industry Pharmaceuticals industry Foundry industry

REFERENCES :

1. Principles of Mineral dressing by A. M. Gaudin

2.www.themagnetguide.com3.www.en.wikipedia.org4.Mineral processing design & operation by A.Gupta & D.S. Yan

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