Attract & retain

Magnetic separation equipment can be customized for C&D recyclers to help maximize metal recovery rates.

Courtesy of Ohio Magnetics

Metals can be valuable end products for construction and demolition (C&D) recyclers who tailor their separation systems to pull magnetic ferrous metals such as high-carbon steel from high-value nonferrous materials such as aluminum and copper, and a magnet separation system often serves as the backbone for metals recovery.

One company with extensive experience in designing magnet separation systems for the C&D space is Ohio Magnetics, a Cleveland-based company that has been in business for more than 100 years. A sister company, Stearns Magnetics, merged operations with Ohio Magnetics in the 1990s, and these days the company specializes in three main types of Stearns metal separation products—suspended magnets, drums and pulleys—all of which are manufactured, engineered and fabricated in its Cleveland facility.

Often called over-the-belt magnets, suspended magnets typically are found in C&D recycling facilities. These magnets are rectangular in shape and can be installed over conveyor belts at different distances from the belt.

Ohio Magnetics works with customers to customize Stearns suspended magnets, which can be tailored to each facility’s needs. The magnets are available in permanent and electromagnet versions as well as manual or auto-matic discharge, also called self-cleaning.

Magnetic pulleys typically are used at the end of a conveyor in a recycling setting to recover the finer materials that the suspended magnet has missed.

Construction & Demolition Recycling spoke with Walt Civovic, a Tier 3 sales manager for Ohio Magnetics who has handled domestic and international sales for the company since 1985, about choosing and maintaining magnetic separation equipment.

“Magnets are very fickle,” Civovic says. “You definitely need to have a substantial amount of knowledge and experience to understand magnets and to apply them properly.”

Construction & Demolition Recycling (C&DR): What types of businesses or facilities typically use magnets, and what are some of the uses that you see?

© Vladyslav | stock.adobe.com

Walt Civovic (WC): Our separation equipment is basically geared toward the recycling industry, as well as mining, utilities, foundries, waste recovery and pulp and paper. These are all facilities that would have conveyors, and during their process, they’re reclaiming ferrous from nonferrous [and other] materials.

For example, a foundry uses a lot of sand to make their casting molds, and one of their greatest costs is the sand that they use. So, they try to reclaim the sand that’s been used for previous castings, but there will be a ferrous material that has entered into that sand. They need to refine and reclaim the sand, and [magnetic] separation equipment is one way to do it.

 

 

C&DR: Can you explain the difference between manual and automatic discharge magnet options?

 

WC: With the manual discharge [model], basically, you have a rectangular magnet suspended above a conveyor. It … will attract any ferrous material to its body, and then once that bottom of the magnet or face of the magnet is filled with ferrous material, the customer actually has to manually swing the magnet over to the side of the conveyor and drop the ferrous material and then swing it back over the conveyor.

The magnets that are equipped with the automatic discharge feature, they actually have a belt running on pulleys being driven by a motor. The belt is constantly turning and what it’s doing is picking up the ferrous material and dropping it alongside the conveyor into a hopper. As a result, no manual power is required to clean the magnet off, so you can run the magnet all day long.

 

C&DR: What would be the benefit of a manual over an automatic model?

WC: I would think two main reasons. One is cost. Obviously, the automatic discharge, with many more bells and whistles, will be more costly and more to maintain. You have more moving parts and components, so you have to maintain it more regularly.

The production [volume], the amount of material that you’re running over the conveyor, [is also a factor in making the decision].

If you’re a high-production facility, then you would probably tend to go with the automatic discharge. With a manual clean, you’re not recovering as much ferrous material on a daily basis, so you don’t need to have your workforce constantly clean it off.

 

C&DR: What volume of metal would a C&D recycling facility need to handle that would make it a good decision to put in magnet separation?

WC: I don’t think we can actually specify a specific volume of metals. It would just make sense to us that the higher the production rate, the more beneficial it would be to invest in magnet separation equipment.

Now, keep in mind, [magnets are] only one part of the complete system. With these types of systems, you have conveyors, you have crushers [and] you have pulverizers, so there’s much more involved in such a process, and we believe that a company that is going to invest in such a system would also want to utilize separation equipment. Otherwise, the only other option you have is manually separating.

 

C&DR: What are some factors that potential customers should keep in mind as they’re choosing magnetic separation equipment?

WC: The customer will come to us and they’ll provide us with specifications as far as the type of material that they’re processing, the rate at which the conveyor will be moving, the amount of material or burden that is required [and] the amount of material stacked on top of the conveyor. So, there’s a lot of specifications that the customer provides, along with their requirements as far as what they’re trying to do.

Courtesy of Ohio Magnetics

Once we have these specifications and requirements, then we can proceed to the next step and send them out what we call an application data form, which requests a good amount of specific information, such as speed, burden, depth, size of pieces, min and max that are possibly ferrous. Is it metal, is it paper, is it wood? Is it coal that we’re cleaning and running through the conveyor?

In this case, it would be C&D markets, so there are a lot of different factors that are considered with the customer. I would think his main consideration is his cost and his process that he’s looking to incorporate as far as recovering the ferrous material.

 

C&DR: What are the challenges that C&D recyclers face when they’re trying to separate out metal?

WC: The challenge in our mind is … No. 1, maintaining the equipment. Some of these applications are very demanding. So, their equipment definitely needs to be maintained properly to run [at] peak efficiency.

Also, they need to make sure that when they are processing the material that [they are staying] within the initial given specifications and requirements that were provided to us.

 

C&DR: What are some of the maintenance needs recyclers must keep in mind with magnets?

Courtesy of Ohio Magnetics

WC: Most of the maintenance would be typically with the self-cleaning units because of the number of moving components. When you’re talking motors, gears, drives [and] oil, you need to maintain the proper oil level.

These over-the-belt magnets are basically energized for most of the … day. They actually have a coolant that’s poured inside these magnets. So, we want to make sure that the oil level is always at the proper height. We want to make sure that there aren’t any [oil leaks], which occur over time, and then just general wear and tear on the magnet itself or the pulley itself or the drum itself. On those, the wear problem is easily visible.

But just general regular inspection and maintenance is the proper way to maintain your equipment, and it goes a long way in making it last.

 

C&DR: What is the typical lifespan of these magnet components?

WC: A lot depends on the customer and how they maintain equipment. How they use equipment also reflects the life expectancy of the magnet. We have magnets out there that have been out for 20, 30 years and then we have some that have been out for only five to 10 years. It all depends on how well they’ve been taken care of. It’s like your car at home, right?

Interviewing and editing by the managing editor of Construction & Demolition Recycling. She can be reached via email at smann@gie.net.

May/June 2025
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