Some fines solutions

Making money from auto shredder residue (ASR) requires more than simply bringing cars in the front gate. A huge factor, as Earl Weber Jr., owner of Garden Street Iron and Metal in Cincinnati, knows, is recovering all the metals possible. That means the big stuff and the fines. Gathering fines not only adds to the amount of aluminum, copper, stainless and other metals recovered, it also reduces expenses on the back end.

Keeping an eye on details is one reason the family-owned operation is celebrating its 55th year in business this year. “Our goal is to recover more metal out of the fluff,” Weber says. He figures Garden Street’s installation of an Eriez FineSort allows the company to do just that.

“Our goal is to pull more minus-5-millimeter material out of the fluff,” Weber says. “We are getting an extra 3 percent, conservatively.”

He says he is less fixed on the exact percentage than he is on knowing that Garden Street’s processing line is more efficient and effective. “I don’t have as much of a trash bill for shredder residue,” Weber says.

Think small

“Fines are something that can’t be overlooked anymore,” agrees Ryan Njavro, general manager for ferrous and nonferrous products at U.S. Shredder and Castings Group, headquartered in Miramar Beach, Florida. “The value is huge, and the system is too easy to operate now not to use.”

A microfines system can recover materials as small as 1 millimeter. This can be done on and off location, Njavro says.

Today, small to midsize shredder operators represent 90 percent of the market, according to Bill Close, applications engineer at Wendt Corp., Buffalo, New York. He says all those shredder operators should be making fines and ultrafines concentrates for sale to others. Simple and relatively inexpensive technologies, such as screening, magnetic separators, high-frequency eddy current separators (ECS), ultra-high-frequency ECS, ballistic separators and air prep, all play a role in creating concentrates for others to upgrade.

The remaining 10 percent of the market—those with large shredders or multiple shredders located closely together—have the volume to consider making additional investments that put them in the position to make high-quality refinery products. “These same fines processors will be in the business of buying the concentrates from the other 90 percent of the market,” Close says.

Fines often are referred to as “undersize” materials. Eventually, a high volume of fines will result in quality and profit issues for companies that do not ride herd on their operations.

“Fines ASR will typically constitute anywhere from 40 to 60 percent (by weight) of the ASR,” says Mike Shattuck, market manager of recycling for Eriez, Erie Pennsylvania. ASR fines can contain up to 60 percent ferrous dirt, which needs to be removed prior to processing.

“In today’s market, a SGM Micro-Fines Plant (MFP) can earn $50 to $55 per ton of ASR fines processed, or $4 to $5 per ton of shredder infeed,” says Didier Haegelsteen, managing director of SGM Magnetics, with North American headquarters in Bradenton, Florida.

He notes that the figure will vary from operation to operation, depending on the shredder feedstock and the equipment installed at the residue plant. Regardless of where on the spectrum a recycler falls, Haegelsteen says his company’s system will leave no more than 0.2 percent of nonferrous metals in the MFP (microfines plant) waste.

In a typical auto shredding system, roughly 2 percent to 3 percent of the fines stream is nonferrous, with an additional 5 to 7.5 percent being ferrous, according to Haegelsteen.

Concentrated effort

A certain volume of fines must be generated before a recycler can consider investing in fines recovery equipment. Njavro says he would like to see around 1,000 tons per month going to the landfill. “In some cases, lately people are seeing their 5/8-inch and under [fines] making up 50 percent of the total weight generated in ASR,” he says.

Close says 1.5 percent of the typical total ASR stream easily can be concentrated with screening and ECS technologies that are well-applied. An additional 0.75 percent can be concentrated using sensor-based and other technologies. Shredder operations of all sizes can benefit from screening and ECS technologies, while midsize and large shredder operations can benefit from the addition of sensor-based technologies.

“All recyclers should make concentrates,” Close says, adding that some should go even further.

In automobile shredding operations, typically nonferrous materials less than 1 inch in size are considered fines. Materials smaller than 1/4-inch are considered by most as microfines. ASR fines are typically treated magnetically not only to remove the saleable ferrous that is present but also to remove the ferritic dirt.

As much as 10 percent nonferrous can be recovered from the ASR between the zorba fraction and the microfines. “It’s fair to say with the correct ferrous recovery system you could pull a few percent on top of your nonferrous with clean ferrous material,” Njavro says.

“Magnetic dirt will affect the recovery and grade of the zorba product produced on the eddy current,” Shattuck says. “For fines material, we will typically use eddy current separators with additional poles (frequency changes) to react better with the smaller nonferrous metals,” he says. The process for microfines is similar; however, the ECS will have more frequency changes.

In fact, one of the main reasons nonferrous metals are lost in ASR fines is because of the entrapment of that valuable fraction in the magnetic dirt. Haegelsteen says that can represent 30 percent to 40 percent of the fines.

“The higher the moisture content of the fines, the more entrapment and the higher the loss of valuable metals in the magnetic dirt fraction,” he says.

Making it work

When Garden Street purchased its FineSort, the company’s goal was to recover 1-inch-minus ASR. However, the line failed to capture some of the finer nonferrous metals. So, Weber purchased another ESC to follow the FineSort. The strategy was to set the FineSort up to produce a dirty zorba, which then passes to the second ECS for further cleaning.

Weber says he is recovering an additional 400 pounds of zorba per hour.

When Weber sold the zorba his operation was producing, he was getting deducted for the 1/4-inch-minus microfines of nonferrous metals that were present. That material would flash off when introduced into a smelter. He decided to buy another ECS, which he uses to cull the microfines.

“We get a mix of aluminum, copper and zinc but not iron,” Weber says. “It tends to run high in copper. There are lots of small wires that we were missing that we now get.”

Garden Street’s microfines output is high in reds, running 20 percent or more. The company also captures a lot of bare copper wire.

The misses from the FineSort, which contain that fine bare copper wire, and the misses from the second ECS with the intentional losses of the 1/4-inch-minus aluminum are presented to an ultra-high-frequency ECS to recover the microfines.

This process is netting more than 300 pounds of microfines per hour, which puts a smile on the face of 87-year-old Earl Weber Sr., who still works from 6 a.m. to 5:30 p.m. at Garden Street

Recovery targets

In addition to ASR, among the other applications that generate recoverable metallic fines are electronics recycling, ash from municipal solid waste incineration and wire chopping, Haegelsteen says.

Wherever the operation, certain areas almost always will profit from a once-over on the fines system. Be aware, however, that such special situations require a bit of rethinking in terms of handling the product, sources say.

“Every processor, regardless of capacity, should at least have basic recovery on the fines ASR,” Shattuck states. “ROI (return on investment) is typically short with the high volumes of nonferrous metal available in the minus-1-inch ASR stream,” he says.

Microfines cost a little more to recover and the percentage of metals is less, so ROI on a microfines recovery system typically will be a bit longer.

A small shredder producing 50 tons per hour typically will produce 10 tons to 12 tons of ASR per hour. This equates to 5 or 6 tons per hour of fines that can contain better than 20 percent nonferrous metals.

Fine zorba is typically sold as a zorba product. A zorba 90 would contain 90 percent metallic material and would fetch a better price than, say, a zorba 70.

Sizing materials is critical to success, Close says, adding that higher volumes and tighter cuts will improve the efficiency of all separators. To that end, his company now offers newly patented ECS technology that recovers metals more efficiently and more cost-effectively, he says.

Most processors earn a small premium for zorba fines over the regular (1-inch-plus) zorba because the red metals percentage is typically much higher. This is what Garden Street realized.

“I’d do it again for sure,” Weber says of his fines recovery project.

The author is a contributing editor to Recycling Today and can be contacted via email at curt@curtharler.com.