Customization called critical in shredding applications

To optimize safety, productivity and return on investment, size-reduction systems in recycling applications should be designed and maintained as an integrated system by a sole supplier that also offers postinstallation support, according to U.S.-based equipment maker BCA Industries.

The practice of recycling involves a “virtually endless” variety of materials, processes, infeed sizes and desired outputs, according to the equipment company, with a partial list including paper, plastic bottles, aluminum cans, obsolete electronics, batteries, catalytic converters with precious metals, medical supplies and construction and demolition (C&D) materials.

“There is so much variability in recycling material, size and processes that each shredding system really needs to be customized to meet the requirements of a specific application, with consideration of the desired throughput and profitability objectives,” says John Neuens, an industrial consultant with BCA Industries, which is based in Milwaukee.

Complicating matters, Neuens says, is that some recycling equipment providers manufacture only segments of a complete system, necessitating the involvement of engineering firms for the specification and assembly of component parts into a more cohesive shredding system.

Neuens says this can lead to a “Frankenstein” system that may never work as intended, requires extensive troubleshooting or may even lack the necessary reliability and safety standards. When multiple equipment sources are involved, resulting technical issues can devolve into “finger-pointing” and blaming others, he warns.

“For optimal efficiency, the shredding system should be designed by a single supplier to ensure seamless coordination and communication among the system’s component parts for achieving the desired output,” Neuens says.

He calls ongoing postinstallation technical support and maintenance a requirement and says it is common for recyclers to reach out to vendors months or years later with the desire to process new materials, many of which have different dimensions and feedstock.

“A single point of contact and accountability is really necessary to design and maintain a custom [recycling] system for optimal productivity throughout its lifespan,” Neuens.

The need for a recycling system often begins with simply the identification of a material that requires shredding, says the consultant. However, the ultimate requirements can involve a complex process of reduction, separation and destruction, according to Neuens.

Given the array of potential outcomes, Neuens estimates a company like BCA has the capability to design and manufacture thousands of shredder systems when considering all the potential markets.

Although BCA frequently collaborates with engineering firms on large projects, the company has an in-house engineering staff that can design what Neuens calls complete recycling systems.

“Naturally, customers are looking for durable, quality recycling equipment at a reasonable cost, but the primary reason we are hired is because of our critical thinking [about shredder design], as well as our in-house design and manufacturing capabilities,” Neuens says.

According to Neuens, BCA’s client roster includes Fortune 500 companies in numerous industry sectors, including aerospace, automotive, electronics, energy and consumer goods, plus the United States armed forces and “some of the world’s largest recyclers.”

“Working with diverse manufacturers over the years has presented complex problems requiring unique solutions,” says Neuens. “Each time we’ve worked with a different material or a novel recycling situation, we’ve learned something and applied the lesson to the next project.”

The emergence of the electric vehicle (EV) industry has provided a new example of designing and manufacturing a shredding and recycling system for the large battery cells configurations found in EVs, which BCA Industries says can be as large as 8 feet long, 4 feet wide and 1 foot thick.

According to Neuens, the first goal is to separate and reduce the material to a more manageable size. To facilitate that task, BCA may use vibratory conveyors, which help to separate the packing material from the product and promote feed regularity.

The vibratory conveyors often move partially separated materials to shredders designed to provide primary destruction. A second or even third shredder may be required to reduce the material to achieve the required minimal size.

The shredded material is then separated using various techniques. Steel, for example, can be separated using stationary overhead, head pulley or cross-belt magnets. While a magnetic separator may not capture all stainless steel, BCA employs rare earth magnets to attract and capture what it calls a significant percentage of that metal.

Nonferrous metals such as copper and aluminum can be effectively separated using a combination of density separation and eddy current separators. Density separation differentiates materials according to varying weights while eddy current separators use a robust magnetic field.

When very fine material sizes are required, such as 10-to-20 millimeter mesh, granulator or turbo mill systems can be deployed. For rubber, a cracker mill with a chilled roller is used for breaking apart, plasticizing and mixing rubber materials, says BCA Industries.

As part of the overall system design, Neuens says it is important to consider how the material will be packaged for shipping. This could involve totes, steel drums, super sack bags or open-top truck trailers. “The outfeed system needs to be designed to accommodate how the client wants to ship the material,” he remarks.

Ensuring seamless integration and communication among all component parts through the programmable logic controller (PLC)-based control system with user-friendly touchscreen interfaces is another critical challenge in shredding system design, according to the vendor.

A quality system includes programmable software to adapt the system for various input types and materials.

“When it comes to recycling batteries, the process varies depending on the size of the battery packs or individual cells being handled,” Neuens says. “To optimize the system effectively, programming software is essential to accommodate for this variability.”

Postinstallation modifications and support can entail being prepared to make adjustments when customers reach out in the future to modify the system for new material types or sizes, Neuens says. Implementing system changes may not be as straightforward as customers perceive.

“Often the customer doesn’t know what the future holds in terms of recycling,” he continues, adding that it is common for recyclers to start with one feedstock and then request processing of additional materials of different types, sizes or geometries.

“If a system is initially designed for processing specific feedstock, customers might seek to modify it to handle tougher materials or larger sizes,” Neuens says. The requested adaptation could necessitate adjustments such as upgrading to a larger shredder, chamber or knives, according to the consultant.

Even the seemingly straightforward decision to switch to a hopper of a different size can pose challenges.

“The geometry of the hopper significantly impacts performance," Neuens says. "The hopper plays a crucial role in material orientation during the feeding process and, therefore, must be properly implemented."

“The variability in materials and processes calls for recycling systems that are not only tailored to specific applications but also maintained as cohesive units," BCA Industries concludes.