Updated for 2026: Selecting the right magnetic separator requires more than comparing Gauss levels or choosing the strongest magnet. Correct separator selection depends on the application, metal contamination risk, material flow, installation position, and separation objective.
Choosing the best magnetic separator for an application is not always straightforward. Many suppliers provide technical details such as Gauss levels, magnetic strength claims, and estimated metal capture rates, but those figures can be difficult to verify and may not tell the full story.
This guide explains five common magnetic separator myths and helps buyers understand what really matters when selecting magnetic separation equipment for food processing, plastics, recycling, quarrying, mineral processing, and general industrial applications.
Contents
One of the most common magnetic separator myths is that the strongest magnet is always the best choice. In reality, the best magnetic separator is the one correctly matched to the application.
Customers often ask for the strongest magnetic separator available, but “strongest” can mean different things depending on how the magnetic field is measured, where it is measured, and what metal contamination needs to be removed.
Before quoting for any magnetic separator, it is important to understand the application fully. Key questions include:
Once this information is understood, experienced engineers can recommend the right separator design, magnetic strength, and installation position.
In many cases, the recommended separator may not be the strongest magnet available. It will be the separator best suited to the process.
Another common misconception is that all rare earth magnetic separators perform the same way. They do not.
A customer may know they need a rare earth magnetic separator because the contamination is small or difficult to remove. However, the term “rare earth magnet” is broad and does not define the magnet grade, construction method, temperature rating, or performance characteristics.
Rare earth magnets are strong permanent magnets made from alloys of rare earth elements, such as Neodymium Iron Boron or Samarium Cobalt. They are significantly stronger than traditional ferrite or alnico magnets.
The two main types of rare earth magnet are:
Neodymium Iron Boron magnets are commonly used in magnetic separation because they provide very high magnetic strength. However, they are available in different forms.
Samarium Cobalt magnets are more expensive than neodymium magnets but are well suited to very high-temperature applications. They maintain magnetic integrity at higher temperatures and are used where standard neodymium magnets may not be suitable.
In magnetic separation, the most common rare earth magnets are neodymium iron boron magnets. However, buyers should ask whether the magnets inside cartridge magnets, tube magnets, or plate magnets are sintered or bonded.
High-quality magnetic separators generally use sintered rare earth material because it provides better physical strength and stronger magnetic performance.
Gauss is often quoted when comparing magnetic separators, but the highest Gauss reading does not automatically mean the best separation performance.
Gauss is a unit of measurement for magnetic field strength, also known as magnetic flux density. However, a Gauss reading only tells part of the story.
There are several problems with basing a purchasing decision on Gauss value alone:
A more practical way to assess magnetic attractive force on smaller magnetic separators, such as tube magnets, grid magnets, and plate magnets, is to conduct a pull test.
A pull test typically involves:
This provides a real, repeatable measurement that can be used as part of an internal audit process.
If magnetic force is important in a purchasing decision, buyers should not only ask for a Gauss level. They should also ask for the pull force required to remove a defined test piece from the magnetic separator surface.
In normal operating conditions, a high-quality magnetic separator should not experience significant magnetic strength loss over time.
However, certain factors can reduce magnetic performance.
The most common causes of magnetic strength loss include:
Regular checks, audits, and pull testing help ensure that magnetic separators continue to perform as intended.
For a deeper explanation of this topic, see Bunting’s article on whether magnets lose strength over time.
In a perfect world, installing a magnetic separator would deliver 100% metal separation with 0% product loss. In reality, this is not achievable in normal processing environments.
Material flow can vary. Contamination size, shape, magnetic properties, product depth, speed, moisture, installation position, and maintenance condition can all affect separation performance.
Before estimating a separation target, several questions should be asked:
In recycling, the objective may be to recover valuable metal. In food, pharmaceutical, and plastics processing, the priority may be to protect product quality and prevent contamination.
If a metal separation target is part of a project specification, there should be an agreed process for measuring performance after installation.
A claim of guaranteed 100% metal separation should be treated with caution. Even carefully controlled processes are subject to variations that affect separation performance.
The right magnetic separator depends on the application, contamination risk, material flow, and separation objective.
Before selecting magnetic separation equipment, consider:
Bunting’s technical team can help evaluate the application and recommend the most suitable separator design.
Magnetic separator selection should be based on application data, not myths. Stronger is not always better, Gauss does not tell the whole story, and no separator can guarantee perfect metal separation in every process condition.
The most effective results come from understanding the material, contamination risk, process flow, and separation objective before choosing a separator.
For further information on magnetic separators, electrostatic separators, metal detectors, or to discuss a specific project, contact Bunting’s technical sales team.