For this FocusOn Mining, Aggregates and Construction feature, we turned to Eriez for insight into the various types of metal removal & magnetic purification.
To eliminate the metal that tear belts, damages crushers, and causes unnecessary downtime to processing equipment, we take a look at Suspended Electromagnets, Permanent Magnets and Magnetic Pulleys as viable solutions.

Suspended Permanent Magnets

Suspended Magnetic separators have proven to be the most effective for the removal of unwanted iron from heavy burdens of material being conveyed on fast moving belts. They are ideal for separation applications on wet or dry, fine or coarse materials in large or small tonnages. Safe, sure, tramp iron removal protects costly processing machinery and assures the purity of the product.

The uniquely designed magnetic circuit is long and flat, providing a greater area of magnetic coverage with a maximum depth of field and with less head room required than with an electromagnet. Operating advantages are many, possibility of accidental shutdown and shutdown due to power failure is eliminated – strength never varies. The unit operates at peak efficiency at all times – no heat is generated. Elevated temperatures in the 100° to 200°F (38° to 93°C) range have virtually no effect on these separators.

Two Models and Two Configurations Available

• Model CP Permanent Magnets
  The CP Magnet are ideal for general tramp iron removal from a range of materials. CP magnets utilize a permanent magnet circuit to provide a continuous and uniform magnetic field across the feed belt to optimize separation efficiency of damaging tramp iron. The self cleaning feature supplied with the unit provides for automatic removal of accumulated tramp metal.

  Features and Benefits:

  • Low operating cost
  • No electrical maintenance on magnet
  • No costly shutdowns
  • Uninterrupted magnetic protection
  • Simple installation
  • Powerful magnetic field
  • Permanent magnet requires no power

  The magnet is placed across the conveyor belt. A moving continuous belt surrounds the magnet box. Ferrous material is attracted by the magnet and is held on the belt. As the belt moves clear of the magnetic field, ferrous metals fall away into bins for collection and disposal. The CP is designed for a maximum suspension height of approximately 10 inches (250 mm) on belts less than 36 inches (1 m) wide. Applications involving wider belts or higher suspension may require a larger suspended permanent magnet.

• Model TP Permanent Magnets
  
  The TP Magnets incorporate a higher strength, dual pole magnet design to offer improved seperation of smaller tramp iron. TP magnets utilize a permanent magnet circuit to provide a continuous and uniform magnetic field across the feed belt to optimize separation efficiency of damaging tramp iron. The self cleaning feature supplied with the unit provides for automatic removal of accumulated tramp metal.

  Features and Benefits:

  • Low operating cost
  • No electrical maintenance on magnet
  • No costly shutdowns
  • Uninterrupted magnetic protection
  • Simple installation
  • Powerful magnetic field
  • Permanent magnet requires no power

  The magnet is placed across the conveyor belt. A moving continuous belt surrounds the magnet box. Ferrous material is attracted by the magnet and is held on the belt. As the belt moves clear of the magnetic field, ferrous metals fall away into bins for collection and disposal. The TP is designed for a maximum suspension height of approximately 12 inches (300 mm) on belts less than 36 inches (1 m) wide. Applications involving wider belts or higher suspension may require a larger suspended permanent magnet.

Eriez Magnetic Pulleys

Eriez provides a uniform permanent magnetic pulley that will transform your belt conveyor into a powerful self cleaning magnetic separator. The axial interpole magnetic circuit provides a uniform magnetic field to remove tramp iron from material on almost any belt conveyor.

Eriez Magnetic Pulleys provide ideal automatic removal of unwanted iron from materials conveyed on belts to prevent machinery damage and product contamination for sand, gravel, limestone, recyclables, wood products, food, chemical, mining, rock products, ceramic, paper, plastic, rubber, coal handling and foundry operations.

Features & Benefits:

• Powerful and reliable
• Prevents machinery damage and product contamination
• Automatic separation of heavy tramp iron from conveyor transported materials

Principle of Operation

Eriez Magnetic Pulleys are widely used as head pulleys in belt conveyors for continuous automatic removal of damaging tramp iron from a variety of materials.
As illustrated in graphic (left), tramp–iron contaminated material comes within the pulley’s magnetic field, the tramp iron is attracted and held to the belt until it reaches the underside, passes out of the magnetic field, and is separately discharged. The cleaned, nonmagnetic material is discharged over the pulley in a normal trajectory.

A stainless steel splitter assembly is required to separate segmented material fractions. An adjustable splitter will permit separation fine tuning and provide optimum separation performance for your application.

Eriez DF High Speed Drum Magnets

Eriez has the separator capable of dry treatment of finely ground iron ore, slag, fly ash and other difficult ferromagnetic concentration and removal problems. High strength, high capacity and a complete range of models and options are available in the Eriez DF High Speed Drum line. Adequate water supply considerations are a thing of the past with this equipment. Areas for exploration and development which formerly could not have been considered for magnetic treatment are now getting another look.

DF Drum Separators operate in a way similar to other drums but with some important differences. Older type, slow, agitating or radial field drums employ only magnetic attraction and gravity as the separating forces. Their capacity is limited due to the slow speed of rotation of the drum shell. The DF High Speed Drums employ high strength magnetic elements and high speed shell rotation. This makes it possible to introduce a third factor in the separation of materials – inertia.

To take maximum advantage of all these forces, Eriez engineered new, powerful magnetic circuits which permit high rotational speeds for the drum shell. Carefully balanced magnetic attraction, field depth and shell speed achieve an efficient, high-capacity machine which effectively throws out fine non-magnetics and retains the magnetics.

For more information of the extensive line of Magnetic Separation products by Eriez, click HERE.