Road to Innovation

Features - Auto Shredding Focus

The auto shredder has become a lynchpin in the harvesting of scrap metal for global markets

July 17, 2013
Brian Taylor


Among the maxims that guide inventors are “Necessity is the mother of invention” and “Genius is 1 percent inspiration and 99 percent perspiration.”

Each of those sayings can apply to the story of the auto shredder’s invention and evolution, a development that has changed the way the scrap industry processes and packages a considerable amount of its metal.

Shredders initially helped scrap processors solve one specific problem, but their implementation and spread allowed recyclers to recover metal in efficient and automated ways from an increasingly complex obsolete scrap stream.

Mill Ready

Observers of the growth of auto shredding might be tempted to think that steel mills buy increasing amounts of ferrous shredded scrap because that is what is now available.

But shredding pioneers and advocates also point to many advantages ferrous shred offers to steelmakers. Electric arc furnace (EAF) steelmakers were especially hungry for the new shredded grade.

In addition to potentially hiding contaminants, bundled automobiles (or baled scrap in general) caused other problems for EAF steelmakers. “Those bundles were bulky and left a lot of unfilled space in each charge. They would have to put in four to five charges to get a melt in those days," says shredder co-inventor Sam Proler.

As well, expensive EAF electrodes were prone to snapping and breaking if they were pressed against a charge made up of bundled scrap, and those same bundles, if dropped into furnace at the wrong angle, could break the expensive refractory lining.

Shredded scrap, by its very nature, has helped provide a sensible solution to all of these dilemmas. “As a dense charge, it could increase melting capacity by 35 or 40 percent,” says Proler. “You’re talking about big money, not even considering the savings from less electrode and refractory breakage.”

Scott Newell of The Shredder Co., Canutillo, Texas, helped take part in a study that he says demonstrates exactly why ferrous shred is the ideal feedstock for electric arc furnace EAF steel mills.

Speaking at the 2013 Middle East Metals Recycling Conference in Dubai, United Arab Emirates, Newell said his company was part of a test at an Ecuadorian EAF steel mill that demonstrated that by using 80 percent ferrous shred, the mill was able to reduce its “tap-to-tap” production time from 67 minutes to 40 minutes.

This gain in production speed turned the mill from a 14,000-tons-per-month mill into a 26,000-tons-per-month mill while also decreasing power usage at the mill. “The use of shredded scrap has saved $35 to $40 per ton in power, electrodes and [melting] additives,” Newell said.

Newell predicted that results like these will help convince more steelmakers that the EAF process fed with ferrous shred is the best way to compete in the future. He says the advantages of the feedstock include high yield, good density, no electrode breakage, less air pollution or emissions and reduced “tap-to-tap” time in the steelmaking process.

A Bundle of Worries

The company that receives credit for having deployed the first auto shredder was motivated specifically by the declining quality of the grade then known as No. 2 auto bundles.


As steel mills during and after World War II looked for scrap metal to make up part of their furnace charge, scrap metal dealers used baling machines to create these bundles.

In the mid-1950s Houston-based Proler Steel Corp. had a problem. The company possessed some 40,000 tons of No. 2 auto bundles but was seeing an absence of interest from steel mills in its product. “Most steel mills didn’t want them—they had too many contaminants, like copper and rubber,” retired Proler Steel executive Sam Proler told Recycling Today for a 2009 story.

“We had to find a way in which to remove the residuals that were in auto scrap—like copper, aluminum, lead and the upholstery,” recalled Herman (Hymie) Proler, former chairman and CEO of the company, which has since been disbanded. Hymie was interviewed for a 2002 Recycling Today story.

Proler Steel’s problem was not unique, according to retired metallurgist and former Luria Brothers employee Dr. Richard Burlingame, interviewed for the same 2002 Recycling Today story. “In those days, to make a No. 2 auto bundle, the standard practice all over the U.S. was for scrap yards to buy auto bodies from the wrecker yards—they had been stripped to some extent—and they would typically torch off heavy components like the frame and cut those up into pieces,” says Burlingame. “Those heavy pieces were called hard steel. Then the hulk that was left had few high-density sections, so it was easily baled. That was your No. 2 bundle.”

When the Armco steel mill in Houston refused to buy Proler Steel’s auto bundles, the alternative for the company was labor-intensive: using torch cutters to “debundle” the auto bales and then trying to harvest the clean iron and steel portions of the bales.

As Sam Proler tells it, during this same time frame on a flight from Utah to Omaha, Neb., he was drinking screwdrivers and trying to think through this problem when the idea of deploying a hammermill on entire automobiles came to him. “I asked the stewardess for paper and a pencil and started sketching what this thing would look like,” Sam told Recycling Today.

Such mills could be found widely in mining applications and even at scrap companies, including Proler Steel and at LA By-products in Los Angeles. The design, consisting of a rotor with attached swinging hammers, was used in smaller machines by scrap companies to crush grades such as turnings and steel can scrap before they headed into the detinning process.

After Sam landed in Omaha he couldn’t wait to tell his brothers Israel (Izzy), Hymie and Jackie, and he was equally eager to contact equipment suppliers who might want in on his idea of running whole automobiles through a hammermill.

Sam says he soon approached existing manufacturers of hammermill-style crushers to see if they would be interested in fabricating his automobile shredder.

One manufacturer “said they could build one if the car is quartered and the motor is removed,” Sam recalls. But that didn’t match Sam’s vision. “That’s going back to the blacksmith era, chopping with a hammer and cutting with a torch,” he states.

“They kept telling me why it wouldn’t work,” says Sam of his discussions with potential suppliers at that time. Eventually Sam found a machine shop willing to work with drawings he supplied to them to fabricate custom parts, while he says he used scrap from inventory to fabricate other parts of his first auto shredder.

“We started in 1956 and it took about a year to build it,” Sam recalls. “We built it near the Southern Pacific railway tracks in our Houston yard and used mule power to help us dig the ditches for the foundation,” says Sam. The mule played a part in a new machine that was about to bring rapid changes to both scrap processing and steelmaking.

Problem Solved

While Proler Steel’s solution to its problem was unique, the problem of unwanted No. 2 auto bundles was becoming common throughout the U.S.

Burlingame, who worked for Cleveland-based Luria Bros. Inc. from 1961 to 1986, says the auto bundles were a low grade of scrap that basic oxygen furnace operators would consume only if the bundles could be diluted in a large melt.

“Everything in that car got baled together—including plastics and glass,” he remarks. “There was no mystery or conniving or dishonesty. Everyone knew what a No. 2 auto bundle was. Steel mills bought them cheap and used them for decades.”

He continues, “In the late 1950s, the total amount of nonmetallics and nonferrous metals was up to 15 percent in a typical body that had been stripped down. It’s hard to believe now that there was any market for these bundles, but there was much more iron and steel used in cars then.”

However, by the mid-1950s, Armco in Houston was not the only mill concerned about the future of the bundles. “More and more plastic and composites and nonferrous metals came into the picture [in scrapped autos],” says Burlingame.

The time was right for the shredder, but Hymie Proler recalls that beyond Sam’s airplane inspiration, there was plenty of trial-and-error-related perspiration involved in the brothers’ efforts to build the first shredder.

When it was difficult for the brothers to recruit existing hammermill manufacturers to help them build a machine, they functioned as their own designers, engineers and fabricators, with Sam and Hymie in particular working up design drawings

Although some experimentation was involved in designing such things as the bearing housings, lubrication systems and dust control system, Hymie says the results were encouraging from the start. “It was amazing that the first time we built it, the shredder was better than we anticipated,” he comments. “We dropped a whole car in there, and there she went.”

Their earliest models—dubbed Prolerizers—did not lack for horsepower. “The original motors were taken from naval destroyer escort vessels and had 12-foot flywheels and 6,000 horsepower,” recalls Hymie.

Prolerizer became a trademarked name, and Sam Proler received a patent for the shredding unit when coupled with the use of bottom grates to produce a sized grade of ferrous scrap.

To produce a marketable ferrous grade, the recovery of clean iron-bearing scrap picked up by drum and belt magnets was the focus of the first machines.

“Initially, we tried a lot of things,” says Hymie, who says they experimented with an oven to burn off the upholstery from shredded pieces. “We didn’t know the magnets would do such a good job. Our first magnet was a belt magnet, but we went to drums because the scrap was wearing the heck out of the belt. The drum had to be strong enough to draw the ferrous scrap to the center without also drawing the residue.”

Much of the engineering and design behind the Prolerizer was indeed homegrown. “Sam Proler is just a good engineer,” says Burlingame. “The Prolers deserve the plaudits and commendations for starting the shredding revolution.”

The Proler family was able to turn its name into a trademarked word that has lived on thanks to a 45-year-old patent. Two years after the Proler Steel Corp. applied for a patent for the automobile shredder it designed, the company filed for another patent that allowed Sam to claim a trademarked name for the process.

In 1962, the word “Prolerized” was trademarked to the Proler Steel Corp., three years after the company wrote to the Patent Office to use the term to describe the scrap created from its new processing method.

The inspiration for the name? “I got the idea from a bottle of milk that said ‘pasteurized,’” Sam recalls.

Proper Feeding

During the 50-year history of Recycling Today, the way scrap recyclers process their metal (more shredding) has been joined by an evolution in the way they move, load and unload it as well.

In the early 1960s, the lattice-boom or cable crane was the workhorse at iron and steel scrap yards. The machines required considerable training, coordination and strength to operate, but with a magnet attached they could suitably move ferrous scrap in and out of rail cars or trucks or into a large baler or shear.

In the 1970s and 1980s, recyclers increasingly began entrusting tasks to hydraulic excavators, which were generally smaller in size and easier to operate. Although the machines were originally designed to dig dirt, they offered scrap recyclers faster cycle times and, in many cases, measurable increases in productivity.

Soon, both manufacturers and dealers of these machines began to offer customized conversions, making modifications to turn excavators designed for digging into material handlers better equipped to lift and move scrap.

Excavator companies offering converted models were joined by specialists offering handlers designed specifically for scrap applications. In a 2001 Recycling Today article, Bill Allen of Liebherr master dealer Republic Crane & Equipment, headquartered in Charlotte, N.C., said Switzerland-based Liebherr had been designing such machines since the 1970s.

By the early 1990s, cable cranes were on the road to becoming the distinct minority in the scrap industry crane population, relegated to a handful of specialized tasks. Feeding shredders was not one of those tasks, as hydraulic handlers became the machine of choice at auto shredder yards.

“Since the beginning of Republic Crane in the 1970s, the entire industry has made virtually a complete transformation from cable cranes to hydraulic machines,” Allen tells Recycling Today in 2013. “These new advanced and highly productive machines made the cable cranes go the way of the dinosaurs.”

European companies such as Liebherr, Sennebogen and Fuchs (now Terex Fuchs) have earned considerable market share in the U.S. by offering machines designed for and dedicated to scrap applications.

In 2012, Caterpillar Inc., Peoria, Ill., acquired part of Wisconsin-based Exodus Machines Inc. to offer its line of U.S.-designed and built scrap handlers under the Caterpillar name.

Innovation and Advancement

The development of the Prolerizer was watched at a distance with intrigue—and in some cases skepticism—by competing scrap companies. “The rest of the scrap industry was stupefied by this,” says Burlingame. “How could you put a car body in a machine and do anything but just stall the mill? They couldn’t imagine enough rotor radius, horsepower and hammer speed to do this.”

But the Prolerizers were powerful enough not just to shred the doors and fenders that typically made up No. 2 auto bundles, but it was soon discovered they also could handle the steel frames and cast iron engine parts that initially were withheld from the shredder.

The Prolerizer shredder worked, but would the resulting product be of interest to steel mills? The answer turned out to be yes, and the person who helped steel mills arrive at that answer was Izzy Proler.

“Izzy had to go out and sell the product, and he was able to make the mills understand what this product was,” recalls Hymie Proler. “He was the one who merchandized it, and he did an excellent job of it.”

The buyer at Armco’s Houston mill was among the most impressed with the new ferrous shred product. According to Hymie, Armco subsequently bankrolled the building of the next Prolerizer in Kansas City to produce feedstock for its mill there.

As shredding plants improved, the grade quickly came to be a premium desired by electric arc furnace (EAF) mills. “It was terrific EAF feed, because it wouldn’t break the electrodes like bales could,” says Hymie. “With this material, electrodes could just penetrate through it.”

With the acceptance of the grade, the rush was on by scrap companies and manufacturers to join the shredder revolution. Companies that built hammermills and shredders for other purposes began offering powerful shredders that could handle automobiles and white goods. A variety of manufacturers began working on equipment that could improve downstream separation of shredded materials, most notable in the U.S. being the work of the Fritz family and Huron Valley Steel of Belleville, Mich.

In Texas, Alton Newell, his family members and co-workers introduced a number of innovations to the shredder, concentrating on ways shredders could operate more efficiently and cost effectively.

Alton’s son Scott Newell, interviewed in early 2013, in particular credits his father for designing a limited-feed system that he says greatly increased the efficiency of auto shredders. As well, he pioneered the use of a reject door for unshreddable objects.

Like the Proler family, the Newell family remained in the scrap processing business in the 1960s while also selling and licensing its shredding technology throughout the country and around the world.

Newell shredders gained considerable market share not only in the United States but also could be found throughout the world by the 1980s and 1990s. “Many of the shredder manufacturers operating today have roots tracing back to a Newell origin,” says Scott, noting that a 20-year licensing agreement in Europe resulted in 40 Newell shredders being built there.

In the early 1960s, potential customers and joint investors also visited Houston to see the Prolers and get into the field of Prolerizing. The Hugo Neu Co. and representatives from one of its Japanese steelmaking customers was one of those visitors. The company eventually signed a deal to bring Prolerizing to Los Angeles, where a Prolerizer was deployed and ships were loaded with ferrous shred and sent to the Japanese mills. Prolerizers also were built in Jersey City, N.J., and Everett, Mass., in part so Hugo Neu Co. could serve additional overseas steelmaking customers.

Other scrap firms throughout North America, some of whom may have scoffed at the Prolerizer idea initially, soon began designing and building their own plants. “They found out we weren’t as crazy as they thought we were,” says Sam.

Operators and equipment makers have subsequently experimented with wet, dry and damp shredding; different rotor speeds; different grate and liner configurations; sophisticated downstream magnetic sorting systems; computer control systems to monitor infeed and energy efficiency; and any number of other techniques to shred autos quickly and efficiently while producing a premium grade of scrap.

Although still known commonly as “auto shredders,” the hammermill metal shredding plants operated today commonly handle appliances and a wide variety of obsolete scrap beyond the autos for which they were originally designed.

A Slow Burn

As Proler Steel Co. in Houston built its first shredders, other scrap companies were trying different ways to make marketable scrap from abandoned autos.

At a Brooklyn, N.Y., location, Luria Brothers Inc. experimented with a system to burn away undesirable portions of automobile hulks.

“The idea was to burn everything that would burn (plastics, textiles, rubber) to get an improved melting yield,” Dr. Richard Burlingame, a metallurgist who worked for Luria Brothers in those days, told Recycling Today for a 2002 article.

The process was labor intensive, however. A disassembly line was set up for workers to remove copper wiring and other nonferrous materials, as well as engine blocks and other cast grade materials. The stripped hulks were sent into a homemade incinerator, where the organics were burned off. “They took the hulks and quenched them, and that released a whole lot of ash,” says Burlingame. “Finally, they put the incinerated and washed hulks into a baler and called the resulting product Luria Blox.”

“They were pretty popular,” says Burlingame of the Luria Blox, “because they did improve melting yield and improved the chemistry.” But the combination of labor-intensive costs and environmental pressures brought about by the handling of the ash, the run-off water and incinerator emissions meant, “it really wasn’t a very profitable product,” the metallurgist notes.

A Place of Prominence

Several yardsticks exist to measure the success of the auto shredding process, including a list maintained and published every two years by Recycling Today.

By 1998, the publication’s auto shredder list included more than 200 known auto shredding plant locations in the U.S.

In the subsequent years, that number has grown by another 50 percent, with more than 300 shredders identified on the 2012 version of the list.

The continued growth is reflective of a number of trends, including:

  • Smaller shredding plants that can be affordable to a wider customer base, including smaller companies and facilities outside of large metropolitan areas;
  • An increase in obsolete scrap as a percentage of total scrap and the desire by small- and medium-sized recyclers to bid for this material; and
  • The use of compatible downstream systems that provide additional return on investment in the form of nonferrous recovery.

As well, the increased shredder population is creating scrap grades desired by customers. On the nonferrous side, the recovered zorba, twitch and other grades recovered by downstream systems have provided much needed metallic units to the booming secondary nonferrous industry in China.

Closer to home, ferrous shred remains a preferred grade for EAF steelmakers in the United States. A survey of U.S. Geological Survey (USGS) figures shows that shredded or fragmentized ferrous scrap has grown from providing 2 million tons of scrap to domestic mills in 1978 to 11.3 million tons 30 years later in 2008.

Economic cycles will continue to cause the number of shredders and the amount of ferrous shred produced to fluctuate.

Few industry observers, however, seem willing to predict that shredding’s overall market share as a processing technique is likely to recede anytime soon.