Primary Reduction Equipment by Mark Henricks

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Construction and demolition companies, landfill operators, recyclers and others faced with the diversity and challenge of the items in United States construction and demolition material flow are flocking to a relatively new solution: low-speed, high-torque shredders. These recycling workhorses can take cement blocks and mattresses as well as wood chunks and other materials and reduce their volume while preparing them for recycling or secondary grinding.

Compared to high-speed grinders, primary reduction equipment is quieter, generates less dust, requires less frequent repair and maintenance and, most importantly, does all this while handling more diverse materials. Other solutions include using low-speed shears, and simply trucking material to landfills without reducing volume, where it is disposed of without recycling.

Machines on the Market
SSI Shredding Systems Inc. of Wilsonville, Oregon, has manufactured high-speed shredders for 20 years, but a few years ago began making low-speed primary shredders, says Terri Ward, sales & marketing director. SSI’s Pri-Max machines feature an open-grate cutting table that allows rock and dirt to fall through without passing through the cutters and generating wear on the cutting teeth. “Pri-Max processes the broadest range of material possible, without bridging, jamming, or overloading,” Ward says.

The Pri-Max comes in several basic models, from the PR-560 capable of handling 1 to 10 tons per hour to the PR-5000 with capacity of up to 150 tons per hours. Prices range from $150,000 for the PR-560 to $950,000 for a loaded PR-6000. The capital cost is an obstacle for many customers, Ward says. “But, overall,” she adds, “a primary reducer can help lower costs, improve recovery and improve the work environment.”

At Granutech-Saturn Systems of Grand Prairie, sales manager, Mike Hinsey says their Model 7246-HT Saturn twin-shaft shredder is the most common one sold for construction and demolition applications. The shredder sells for $228,000 and is sold primarily in Europe and Asia. “We do far more bulky shredding for C&D outside North America than inside North America.” says Hinsey.

Badger Shredding Products Inc. in Sturgeon Bay, Wisconsin, employs a patented blade and shaft design that allows it to process concrete containing up to one-inch rebar. “One of the unique features of our machine is the ability to crush concrete with rebar in it,” says Bob Lamer, vice president and general manager. “And it also handles asphalt and aggregate materials.”

The B-2060 from Badger is priced at $440,000 to $525,000, depending on features such as an optional magnet that pulls rebar out of the crushed concrete to facilitate recycling. Another special feature of the B-2060, Lamer says, is its outrigger system that jacks the machine up for easy loading and unloading from a trailer for transport.

The Annihilator from Continental Biomass Industries Inc. of Newton, Ohio, uses a single shaft instead of the dual-shaft design of most primary reducers. Hydraulic engineer Eric Eskeland says the design is intended to break less often than twin-shaft, metal gearbox types when encountering un-shreddable items. “A hydraulic system drives it so there are no gearboxes,” Eskeland explains. “I can cut the pressure spikes off on that machine and never exceed the torque limit of the shaft and motors.”

Annihilators cost from $750,000 to $800,000. Eskeland says the price is warranted by reduced downtime. Annihilators process the full range of C&D materials, from concrete and granite to cast-iron manhole covers and mattresses. “That kind of material goes through without causing a blip on the screen,” Eskeland says. “The only thing the machine won’t eat is solid steel structural pieces.”

Another approach to primary reduction is taken by the PowerMaster, manufactured by Karl W. Schmidt & Associates Inc. of Commerce City, Colorado. Rather than attacking with tempered steel teeth and brute strength, the PowerMaster employs a tornado-force air stream to reduce wood, concrete, glass, and similar C&D materials. Chunky materials are reduced by the force of impacts against other items in the C&D stream, as well as against the armored sides of the unit.

Jeffrey B. Van Galder, sales manager, says the PowerMaster also employs inexpensive sacrificial parts to reduce maintenance costs. “The things that make it stand out in the marketplace are low operating cost, minimal maintenance cost and extreme ease of repairs on site,” says Van Galder. Depending on configuration, a PowerMaster is priced at $175,000 to $275,000. Complete systems including conveyors, sorting stations, eddy currents and other equipment can cost up to $750,000, Van Galder says.

Primary Challenges
Primary reduction equipment is up to most challenges in a typical C&D stream. Structural steel I-beams of 12 inches or more in size will, however, choke low-speed high-torque shredders. Big chunks of concrete, especially when laced with reinforcing bars, also generate mixed success when fed into primary reducer hoppers. Depending on the technology, state of repair and other factors, items such as steel cables and manhole covers may also process incompletely or not at all, while also generating costly downtime while machines are cleared of jams, wraps and other obstructions.

Typically, primary reducers will sense indigestible items and, after attempting to process the piece a few times, reverse and disgorge the item. Not infrequently, tough cases remain wedged between the shredding teeth or rollers and must be dragged out with a chain connected to an excavator. Sometimes wire, carpeting or other material becomes wrapped around the cutting teeth, reducing the machine’s efficiency and requiring time-consuming removal with a cutting torch.

In the worst case, despite the slow speeds as low as a few dozen revolutions per minute, the shredder will damage its transmission or other critical part. However, at best, primary reduction equipment turns the vast majority of C&D debris into six-inch or smaller chunks well suited to sorting and picking on recyclable recovery lines, as well as being much easier to haul and compact into landfills than unreduced debris.

Primary Future
Primary reducers are relatively recent introductions to the recycler’s arsenal. Part of the reason for the introduction of the machines has to do with longstanding problems with processing C&D material with high-speed grinders. Increased prices for recyclables, such as rebar, encourage efforts to recycle instead of dispose of C&D materials. Higher fuel costs and regulations making it tougher to cost-effectively transport materials from construction or demolition site to landfills also play role. In areas with limited landfill space, primary reducers can help get more use out of available landfills.

The natural disasters of 2005, which left vast areas with mountains of recyclables that challenge high-speed grinders, are yet another force drawing people to primary reducers. “That’s a huge market for us,” confirms Badger Shredding’s Lamer. “We’ve been talking to several people in hurricane stricken areas that are very interested in our machine.”