Permanent Magnet

PERMANENT MAGNET

The magnet system in ferrous separation applications as used for raw materials is built from permanent magnet or electromagnets, plus other components some magnetically conducting and others not. "emi-magnetee" pays particular attention during the design and construction of magnet systems to the design and dimensions of the various components. Even the combination of the various material properties is of utmost importance in arriving at a system with the best performance. To ensure that this excellent performance is retained in during operation, particular attention must be paid to the choice of components used when constructing the conveyor belt for use with the ferrous separation unit. For example, you shouldn't use any magnetically conducting materials in the operational area of the magnet system. If you do, these materials could become magnetised which would lead to accumulations of ferrous contamination in the wrong places or adversely influence the efficiency of the ferrous separation process. Materials that can be used in the construction are, for example, aluminium, brass, stainless steel (AISI 300 series) and plastics. "emi-magnetee" technicians will be pleased to advise you on integrating ferrous separation systems in your environment. In the construction of magnet systems, various magnetic materials can be used. The selection is made depending on the requirements which can vary from situation to situation. Some of the groups of materials frequently used by "emi-magnetee" are explained in the following sections.

Ceramic
This magnetic material is used in many in ferrous separation systems. In normal use, a lifetime auarantee is given for its magnetic properties. The material can be recognised by its matt black colour.

AINiCo
AINiCo is an alloy made from aluminium, nickel, cobalt and steel. It is used in situations where great mechanical strength is required. The material is also able to withstand high temperatures and temperature changes. It is recognisable by its typical metallic appearance.

Samarium Cobalt
Samarium Cobalt is a powerful magnetic material made from rare earth minerals. It is almost impossible to demagnetise and always retains a very strong magnetic power. The material can be recognised by its dull metalic colour.

Neodymium
This is the strongest magnetic material currently available. It is used in situations which demand a very through ferrous separation. "emi-magnetee" uses this material in systems for separating ferous contamination from raw materials in which very small particles ( range) are present or the types of steel to be extracted have weak magnetic properties. Neodymium magnetyics can also be used successfully for ferrous separation from viscous fluids. Neodymium is a rare earth material.

Temperature Stability of magnetic materials

Generally, the effectiveness of a magnet of a magnet system drops as the temperature rises. In practive, this has to be taken into account only rarely because mosty applications run at normal ambient temperature. However, every magnetic material has a critical temperature at which its magnetic properties can be demaged. If the limits are not exceeded, the loss of magnetic power will only be temporary and the original magnetic power will be regained when it cools. Naturally, it is sensible to keep a good safety margin. For applications in which there is a chance that higher temperature could occur, it is recommended to seek advice from in advance. Our extensive experience gained over many years in the application of magnet systems in industrial environments ensure the best solution for every ferrous separation problem.

his magnetic material is used in many in ferrous separation systems. In normal use, a lifetime auarantee is given for its magnetic properties. The material can be recognised by its matt black colour.

Neodymium
This is the strongest magnetic material currently available. It is used in situations which demand a very through ferrous separation. Bakker Magnetics uses this material in systems for separating ferous contamination from raw materials in which very small particles ( range) are present or the types of steel to be extracted have weak magnetic properties. Neodymium magnetyics can also be used successfully for ferrous separation from viscous fluids. Neodymium is a rare earth material.

Temperature Stability of magnetic materials

Generally, the effectiveness of a magnet of a magnet system drops as the temperature rises. In practive, this has to be taken into account only rarely because mosty applications run at normal ambient temperature. However, every magnetic material has a critical temperature at which its magnetic properties can be demaged. If the limits are not exceeded, the loss of magnetic power will only be temporary and the original magnetic power will be regained when it cools. Naturally, it is sensible to keep a good safety margin. For applications in which there is a chance that higher temperature could occur, it is recommended to seek advice from Bakker Magnetics in advance. Our extensive experience gained over many years in the application of magnet systems in industrial environments ensure the best solution for every ferrous separation problem.

Magnetic Properties

Magnetic Properties Rel.strength	BHmax KJ/m³	Br mT	IH_c kA/m	Rel. Strength	Curie temp.°C
Ceramic	27.8	390	255	100	450
AlniCo	44	1270	51	80	860
Samarium Cobalt	154	890	1200	400	720
Neodymium	280	1150	1000	500	310

Custom-made ferrous separation and metal detection systems

"emi-magnetee" field engineers will be pleased to assist you in specifying the optimum solution for your specific ferrous separation problem. If you would like to make use of this service, please fill in a copy of the questionnaire on page 38 . You will then quickly get your tailor-made advice.