Magnetic Separators

Magnetic Separators — Clean Out Iron Contamination

Magnetic separators form the core of magnetic separation technology. By removing unwanted metal contamination from solid, powder or liquid product streams they protect machines, finished products and processes. Whether the product is food, plastic granulate, powder or liquid, a well-designed magnetic separator is indispensable for safe, efficient and reliable production.

What is a magnetic separator?

A magnetic separator is a system that uses magnetic fields to remove iron (ferromagnetic) and weakly magnetic metal particles from the product stream. Depending on the product form and the process step, the separation can take place in free fall, under pressure or on a conveyor belt. This prevents plant damage, reduces downtime and improves product quality.

The performance of a separator depends on three factors:

• Magnetic flux density (the strength of the field)
• Contact time (between the product and the magnetic surface)
• Flow dynamics (free fall, pressure, conveying)

A well-designed separator combines these elements; metal contamination is captured efficiently without obstructing the product flow.

Types of magnetic separator

• Free fall — for dry streams where powders, granulate and pellets fall vertically (drawer, grate, bar, hopper, chute and rotary types).
• Pipeline — for liquid and paste products such as sauce, oil and coatings in closed pipelines; 316 stainless steel, CIP compatible.
• Conveyor belt — for bulk streams on a belt (overband/suspended, head-pull or drum); recycling, mining, cement.
• Other — special applications such as coolant, bag filters or the laboratory.

Material selection and magnetic force

The strength and efficiency of a separator depend on the magnet material used. Most modern separators use Neodymium magnets because of their high flux density and their resistance to loss of magnetization. In high temperature or aggressive chemical conditions Samarium-Cobalt (SmCo) is preferred. The right material choice determines both the separation force and the service life of the system.

Areas of application

They are used in the food, animal feed, chemical, mining, recycling, plastics processing and pharmaceutical sectors. Their principal functions are: removing metal contamination from bulk streams; protecting sensitive machines such as mills, pumps and extruders; food safety and product purity; preventing ignition sources in ATEX-sensitive environments.

What to watch for when choosing a separator

• Insufficient magnetic force: too low a flux density leaves fine magnetic particles in the product, leading to rejects, wear and downtime caused by blockages.
• Wrong placement: a separator that is not put at the right point loses much of its effectiveness. The most efficient separation is done ahead of critical machines or at the inlet of a silo, mixer or pump.
• Lack of maintenance and inspection: even the strongest magnets require periodic cleaning; accumulated particles spoil the magnetic contact and the purity of the product.
• Non-ATEX version: in dusty environments static electricity can cause ignition; only ATEX-certified separators (zone 1, 2, 3) ensure safe operation.