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Drum separators are used in applications where there is a high throughput of material to be processed and where there is a need to extract smaller ferrous particles from a given product stream. Our magnetic separator range is available in a wide range of sizes to suit a customers specific throughput requirements and can either have an internal permanent or electromagnet system depending on the application.

Operating Principle

Magnetic drums are constructed with a 180-degree stationary magnet system, around which a cover revolves. The material is fed onto the drum cover at the leading point of the magnet section. Magnetic materials will adhere to the drum cover as it revolves and will then be discharged behind the normal trajectory. Non-magnetic materials will free-fall forward following their normal trajectory.

For applications that may involve co-mingled materials, Bunting can offer a magnet system that features an alternating pole arrangement as shown in the image below. This magnetic separator system enables the entrapped ferrous materials to flip over the magnetic poles as they move over the surface of the drum and become free from the non-metallic product.



Permanent Drums

Permanent Drums Separators are designed for the continuous extraction of ferrous materials from a product being fed uniformly on to the face of the drum. As the material is fed onto the drum, ferrous materials are extracted and are firmly held to the drum face by the magnetic separator until they move away from the magnets influence and discharge, leaving any non-ferrous materials to free fall.

Permanent Drums have a 180 degree stationary magnet system within a revolving cover. The magnet system is constructed using fully stabilised strontium ferrite permanent magnets. The magnets are mounted on to heavy-duty back plates, to optimise the magnetic strength directed at the product stream. This not only enhances the Drums performance but also reduces the magnetic fields in the shaft and bearings, helping to extend their service life.

High Intensity Rare Earth Drums

For applications that require a much greater level of magnetic separation, Permanent Drum Magnets can be constructed using the highest grade of Neodymium Iron Boron magnets. High-Intensity Rare Earth Drums are capable of extracting fine ferromagnetic and paramagnetic materials, which may not be extracted using a standard Permanent Drum. Rare Earth Drums are most often fitted into totally enclosed housings described in more detail below.

Totally Enclosed Permanent Drums

In applications where product needs to be kept from external contamination or where dusty product must be contained from escaping into the working environment, Permanent Drums can be supplied with totally enclosed housings.

Housings can be manufactured in robust mild steel or stainless steel. Inspection covers, aspirators and diverter plates are provided as standard.

Fragmentiser Electro Drums

Fragmentiser Electro Magnetic Drum Separators are used to continuously remove ferrous metals from a product stream in applications such as municipal refuse and vehicle recycling plants.

These particular Drums are typically used where magnetic materials may be entrapped or buried beneath non-metallic materials. The Fragmentiser Drums are designed to allow extracted magnetic materials to roll over the face of the drum to release any non-metallic materials that may be caught between the ferrous material and the magnet.

Advantages of Mastermag Fragmentiser Electro Drums

1. The axial pole design gives continuous high field strength at the separation zone. The effective magnet width is maximised thus ensuring even cover wear and minimum burden depth of material.

2. The bipolar alternate pole arrangement ensures a cleaner separation of ferrous and non-magnetic materials. This is because materials, which may be entrapped are allowed to roll over the face of the drum, helping to release the non-metallic materials from the magnetic materials being extracted.

3. The high-intensity primary coil concentrates maximum flux at the point of extraction whilst the lower intensity secondary coil ensures that ferrous material is transported to the point of discharge.

4. Ducted coils give an improved cooling, this results in a low winding temperature allowing higher intensity and a longer coil life.

5. Wear covers 8mm thick minimum in manganese steel incorporate bolted joints for ease of cover replacement.

Slag Processing Drums

Master Mag Slag Drums are used for heavy-duty continuous separation of ferrous from non-ferrous material. There is a 180 degrees stationary magnet, with two heavy-duty 8mm thick manganese covers that revolve around it, with the outer one being replaceable. The Slag Drum has a very powerful magnet system capable of extracting ferrous material, which may be entrapped within non-metallic materials.

The Slag drum differs from fragmentiser drums, having a radial pole rather than an alternate pole. This is to ensure that extracted ferrous materials are firmly held to the drum face through its entire 180-degree cycle, allowing for the highest levels of separation.

Wet Drum Separators

Wet Drum Separators are mainly used for the recovery of magnetic/ferrosilicon in dense media plants and iron ores. Wet drum separators work on a similar principle to our other existing drum separators. A stationary magnet system with several radial poles attracts the magnetic material to the drum face. The rotating cover then carries the magnetics from one pole to another, at the same time rotating the magnetic particle to allow trapped non magnetics to free fall.

This should then produce a clean magnetic product completing the magnetic separation process. Wet drum separators have three basic designs that work with 3 different types of application, they are concurrent, counter flow and counter current. The purpose of this is to ensure that we can meet recovery figures of 99.9% when dealing with different solid to liquid ratios.


Typical applications for the Mastermag range of permanent and electro drums are;

  • Removal of ferrous contaminants from glass cullet
  • Recovery of scrap ferrous metals in ELV plants
  • Removal of ferrous particles from powder or granular materials
  • Recovery of ferrous materials from incinerator bottom ash
  • Removal of fine ferrous particles from foodstuffs
  • Separation of ferrous in slag processing applications
  • Recovery of ferrous metals from municipal solid waste