March 2006

Equipment Spotlight

Ferrous Shredders
by Mark Henricks

—View a list of manufacturers at the bottom of the page

At the heart of every ferrous recycling installation, a shredder labors away reducing sheets, bars and blocks of steel and iron into more easily managed strips and chunks. Automobiles, white goods, mattresses and many other recyclable items are dealt with by ferrous shredders, densifying the metal for easy hauling or reducing it for additional processing. High prices for both fuel and scrap are driving solid demand for ferrous shredders for clients from scrap yards to automakers.

Shred-TechShredders come in two main varieties. High-speed, high-horsepower hammermills are favored by auto shredders and others for their ability to process large volumes of heavy steel and iron objects. They pound materials destined for recycling into bits, using club-studded shafts rotating at around 1,000 rpm to crush input against the sides of steel drums until particles fit through a sized grate.

Low-speed, high-torque shear shredders typically operating at 30 rpm or slower pull and cut apart materials using knives mounted on electrically or hydraulically rotated shafts. While not as frequently used for shredding automobiles, shear shredders excel as low-horsepower solutions for shredding steel drums, filing cabinets and metal turnings.

Metso Texas Shredder’s high-speed hammermills are primarily used for automobile recycling, according to Jim Schwartz, technology and international sales liaison for the San Antonio-based company. Metso Texas also sells into applications for handling steel logs and miscellaneous scrap, at rates from 30 tons to 350 tons per hour. Williams Crusher

Metso models are denominated according to hammer diameter multiplied by rotor width and range from 60 x 80 to 122 x 108. Primary drive electric motors vary from 1,000 to 10,000 horsepower. Metso’s computer-controlled water injection system reduces smoke, dust and overall pollution while reducing the danger of fire in the rapidly spinning mill.

Metso Texas Shredder resulted from the combination last year of Texas Shredder with a unit of Finland-based Metso Corp. Schwartz, formerly a principal of Texas Shredder, says demand is strong from scrap companies and steel companies with their own scrap operations. “Because scrap prices were low for several years, there was apparently pent-up demand,” he says.

Shred Pax Inc.’s low-speed, high-torque shear shredders utilize two shafts bristling with knives and rotating in opposite directions. Direct drive motors range from 5 to 10 horsepower for the AZ-7, used for shredding metal turnings, to up to 100 horsepower for the AZ 160 and AZ 200, suitable for car bodies.

Pieper says Shred Pax machines are in size reduction applications from recycling to manufacturing. “Business is strong,” says Pieper. “If it continues the way it started, we’re off to one of our best years in the last couple.”

Shred PaxTwin-shaft shredders from Shred-Tech of Cambridge, Ontario, may employ electric or hydraulic power trains. Hydraulic shredders shine at handling jams, says Sean Richter, senior technical salesman. “It allows the machine to slow to almost zero rpm to cut through tougher materials,” Richter says. Shred-Tech’s ST models used in ferrous shredding applications go from 600 horsepower to 1,200 horsepower.

In recent years Shred-Tech introduced an offset hex knife configuration to reduce load on the machines while also allowing processing of larger materials. Machines have gotten larger. Until fairly recently, the largest was the ST-500, with an 8-inch hex-shaped shaft driving 235,000 lbs. of cutting force. “Then for a magnesium application a few years back we designed the ST-1200,” says Richter. That model’s 10 7/8-inch shaft produces 300,000 of cutting force. “It allows you to reduce bigger products, multiple layers and nested products,” Richter says.

SSI Shredding Systems Inc. of Wilsonville, Oregon, produces both twin- and four-shaft low-speed shredders. Most applications are for mixed-waste streams that include ferrous content, such as turnings and other manufacturing byproduct, file cabinets and fork lift battery casings. “The advantage of shredding is to improve material handling and facilitate further recycling,” says Dave Wilson, technical salesman.

SSI shredding SystemsSSI’s twin-shaft models, ranging from the 30 horsepower M55 to the 600 horsepower M160 are suitable for white goods, cast metal, mattresses and the like. Cutting chambers vary from 23 inches by 31 inches to 64 inches by 101 inches. Hopper openings go from 42 inches by 51 inches to 94 inches by 144 inches.

SSI’s four-shaft Quad system is a recent introduction. Quad models come in configurations of power, cutting chamber and hopper size similar to the company’s twin-shaft models.

Wilson says the Quad’s four close-tolerance cutting disk-equipped shafts allows more control over particle size. Twin-shaft shredders typically produce long strips, which make it difficult to separate materials for further processing, Wilson says.

“With the SSI Quad shredder it is possible to shred a mixed waste stream that contains ferrous, non-ferrous, fabric, plastic, etc. and produce a uniform particle size with one machine in one step using desirable low-speed technology,” he says.

Whether they produce hammermills or shear shredders, no matter what the features and technology, manufacturers all report strong demand for ferrous shredding applications. “Probably the biggest thing in the market is steel price,” says Shred Pax’s Pieper. “With steel prices doing what they are, the steel industry is looking for shredders. The phone’s starting to ring with people asking what do you have and what can I get quickly.”

Company Name
Contact Person
American Pulverizer Skip Anthony 314-781-6100
Granutech Saturn Systems Inc. Damon Dedo 877-582-7800
Harris Waste Management Group Coleen Helland 800-373-9131
Metso Texas Shredder Jim Schwartz 210-581-7921
SSI Shredding Systems Inc. Dave Wilson 800-537-4733
Shred Pax Inc. Paul Pieper 630-694-1100
Shred-Tech Sean Richter 519-621-3560
Williams Crusher Carl Rehmer 314-621-3348



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