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Our company is a specialist in field of magnetic separation

We develop, produce and apply devices for magnetic separation. Our magnetic separators are designed and manufactured exactly in a made-to-measure way as per your needs.

16. 11. 2023

Suspended magnet - limestone processing equipment protection (case study)

Initial status

Our customer specializes in the mining and processing of limestone. When transporting limestone on a belt conveyor, problems arise with metallic impurities such as bolts, nuts, and other larger ferromagnetic particles. These impurities can damage subsequent devices (mills, crushers) and cause an interruption in the production process.


As the excavated limestone is transported on a conveyor to the mills, crushers and other equipment, the ferrous objects can damage the processing equipment and cause production shutdown as well as costly repairs. In particular, larger ferromagnetic objects caused damage to the mill and also to the conveyor belt. The company was unnecessarily burdened by the cost of repairing the mill and the production shutdowns.

During processing, the limestone is transported on a belt conveyor with a width of 1,200 mm, the speed of the conveyor is 2 m/s and the height of the limestone layer on the conveyor is around 250 mm. 


First, we checked the amount of the tramp iron. Together with the customer, we found out that the occurrence of the metal objects was only low. Therefore we designed a suspension magnet with manual cleaning as a suitable separation solution. Since the occurrence of ferromagnetic particles was low, there was no need to install an overband magnet with automatic cleaning (and burden the customer with unneeded higher acquisition costs). However, the installation of a magnetic separator was necessary, as even a single ferrous object could cause serious great damage to the processing equipment.

For the given application, we proposed to use a ferrite suspended magnet, as ferrite magnets can generate a sufficiently strong and deep magnetic field needed for this application.

We produce suspended permanent magnets in several series according to the required magnetic strength and suspension height. We chose a suspended magnet of the DND-MC Mp series, which allows extracting ferrous particles from a depth of 340 mm (it was necessary due to the height of the limestone layer on the conveyor).

The magnet is suspended above equipment using chains, it extracts ferrous contaminant material from the product stream and holds it against the face of the magnet until it is manually cleaned by the operator.

Benefits of using the DND-MC Mp4 F suspended magnet:

The application of the DND-MC Mp4 suspended magnet on the limestone processing line has proven to be an effective way to limit crusher and mill failures and reduce the occurrence of the magnetic  contaminants. It also brings financial savings thanks to the reduction in production downtime.

The company can now run its operations more efficiently and at lower costs, which increases its competitiveness.

The use of the DND-MC Mp4 F suspended magnet had the following positive consequences:

  • Cost reduction - separation of ferrous contaminant material from the product stream results in equipment damage prevention and significant reduction of repair costs.
  • Quality assurance - the material transported on the conveyor is now clean and free of tramp metal -  this improves the quality of the company's final products.
  • Increased efficiency – downtime, originally caused by the ferrous contaminants, was eliminated, what enhanced the overall company's efficiency and productivity.
  • Quick investment return thanks to significant financial savings.

Applied equipment: DND-MC Mp4 F suspended magnet

Advantages of the DND-MC suspended magnet 

  • Installation height up to 450 mm
  • Separation of ferrous particles in size from 0.5 up to 300 mm
  • Max. speed of the conveyor belt: 3 m/s
  • 10-year warranty
  • Light neodymium alternatives
  • Made to measure separators
  • Selected models permanently in store