FREQUENTLY ASKED QUESTIONS

Q- What is tramp iron?

A- It is any shape of ferrous material which may damage crushers and belt conveyors.

Q- What are the most difficult or easiest pieces of magnetic material to be removed?

A- Particle shapes such as spheres, cubes and hex nuts are the most difficult. Shapes such as plates, rods or shredder scrap are easily removed by the appropriate magnets.

Q- Why is a suspended magnet best placed over the head pulley or trajectory of the material?

A- The impetus of the belt velocity provides an assist in moving the ferrous particle into the face of the magnet. A transverse arrangement is more difficult.

Q- Why is knowing the bulk density of the product important to tramp iron removal?

A- If the bulk density number is increased it becomes more difficult to remove a ferrous particle. If the bulk number decreases the easier it is to be removed. For instance copper ore versus wood chips.

Q- Can a 300 Series stainless steel particle be recovered by a magnet?

A- 300 Series Stainless is austenitic (non-magnetic) in fabrication. If, however, it is work hardened or shredded, it may change characteristics to martensitic (weakly magnetic).

Q- Can a 300 Series stainless steel particle be removed by eddy current separation?

A- Yes and no. If it is weakly magnetic, it will be attracted and be ejected into the ferrous partition. If If it is totally non-magnetic, it will be ejected.

Q- What does the terminology “axial” or “radial” pole mean in magnetic devices?

A- The terminology is primarily used on magnetic drums. An axial pole unit is designed with magnetic poles alternating along the circumference of the drum, remaining the same along the drum width. A radial pole is designed with magnetic poles alternating across the width of the drum, and remaining the same along the drum circumference.

Q- Why is the polarity of these drums important?

A- Ferrous shapes, if fairly uniform in size, can be separated with axial pole units. Rod shapes such as sprews and gaggers in foundry scrap require the orientation that the radial poles produce, affording the particle to be oriented along the drum width.

Q- Can eddy current separators produce a separation between a variety of non ferrous metals?

A- This is a roll of the dice. If all the materials being fed to the EC are uniform in size then it may be possible. If they are not, then all the recovery will be mixed metals, with the recovery position located on the material with highest conductivity and lowest density.