Think ahead: installing a shredder to fit expected volume can require considerable research.

Metals recyclers have become more convinced than ever in the past few years of the wisdom of operating a shredding plant to process the diverse obsolete scrap stream.

During the metals price spike of the past several years, recyclers have invested in larger capacity shredders as well as in more extensive downstream systems to harvest every ounce of ferrous and nonferrous metal that goes through the mill.

Limiting factors, though, can include a realization that cash flows may not always be as healthy when prices are down, as well as the important consideration of how much scrap can be procured in a given market region.

Examining these market realities can be a critical step when recyclers work with shredding equipment suppliers to design and install a new or upgraded system.

ORDERS UP. Jim Schwartz of Metso-Texas Shredder Inc., San Antonio, determined that more than two dozen shredding plant installations were underway at the time of a presentation he gave to the Shredder Committee meeting at the Spring 2006 Bureau of International Recycling (BIR) World Recycling Convention. (The event was held at the China World Hotel in Beijing May 29-31.)

Schwartz remarked that conversations with fellow shredding equipment suppliers revealed that, as scrap recyclers ramp up their capacity to produce shredded grades of scrap, some 26 shredding plants have been installed or are underway since the committee last convened in Milan, Italy, in October of 2005.

Schwartz estimated that about 25 percent of these plants are new shredder locations, while the remainder are expansions or upgrades of existing shredder plants.

"There is a bit of shredder mania going on," said Schwartz, who noted that many of the new plants are large models powered by 6,000-hp or larger motors, as the world's scrap recyclers push past more than 100 million tons of shredded scrap produced annually.

China has only five shredding plants, Schwartz says, "plus one more on the way."

In North America, where auto shredding was born and has been taking place for several decades, investment in the technology remains considerable, with the first factor many recyclers consider being just how large of a shredding plant is practical to operate at their locations.

MATCH MAKING. Shredding equipment providers may encourage recyclers not to buy a shredder that is so small that they "outgrow" it, but at the same time they can also caution recyclers not to buy a plant that is too large for the market region.

"The buyer needs to know what his expected volume of scrap will be and whether there is any other scrap available to reach out for," says Mark Mullins, a former shredding equipment sales manager who now operates Metal Shredding Solutions, San Antonio, a shredding system consulting service.

Some of the factors are obvious: "The bigger the population, the larger volume of scrap that is generated," says Mullins. The competitive landscape should also be surveyed, according to Mullins. A prospective shredding plant buyer "should be aware of all of the other shredders already operating in the intended area."

Skip Anthony, vice president of sales and service for shredder manufacturer American Pulverizer Co., St. Louis, also says that "location is key when evaluating adding a new shredder system to an area that is already supporting several other systems."

Adds Anthony, "It doesn't make sense to put in a 98 x 104 machine if the area will only support 5,000 to 6,000 tons per month. You need to be able to comfortably purchase your raw materials without creating a price war with other existing yards."

Confidence in one's ability to compete should not turn into over-confidence that forces bad decisions, vendors seem to agree. "I agree in general that the larger shredders do operate at a lower cost per ton, but I do not advocate that everyone should buy a 120-inch mill," says Mullins.

Allocating sufficient spending on sorting technology can be even more important, according to Anthony. "We would suggest that the customer consider utilizing the proper sized shredder based on material availability (with a cushion) and spend the additional money on downstream equipment for maximum recovery," he advises. "The money is made on these capabilities."

A counter-argument is that larger machines operate at a lower cost per ton, as noted by Mullins, and that they allow an operator to run thicker, heavier objects through the mill.

Some vendors and scrap recyclers alike "believe that the cost per ton is cheaper to turn the larger shredder and that even if you only run a few hours per day, it would be beneficial," says Mullins.

This strategy can have advantages, says Anthony. "It can be cost effective to operate a larger shredder fewer hours due to the limitation of product to feed it," he says. "The more tons you can run in fewer hours will save in direct labor costs. [And] in some areas, by running on a limited time frame there are electrical cost savings."

Mullins offers a variation on this strategy. "I am not an advocate of turning on your shredder for only a few hours a day," he states. "It is a proven fact that all shredders operate at maximum efficiency when the shredder box is running full of scrap all of the time. I believe that if the shredder operator knows that he will only run three hours a day that he will 'baby' the feed and will not keep the shredder chamber full. It is also dangerous to assume that you will not have unscheduled downtime. I would rather see you run the shredder at full production for a complete day and then not run it the next day rather than [run for] three or four hours each day. Once you turn on the shredder you should run it for your full scheduled production day."

Buying a large plant just to run heavier steel through it also carries risks, says Mullins. "Bales and bundles work well in 98 x 104 and 120-inch shredders but have trouble in the smaller shredders," he comments. "The larger shredders will handle heavier scrap but they do not give you a license to shred 'everything,'" he adds.

SHOPPING TIPS. When shopping for shredders, Mullins advises listening closely to manufacturers, but also seeking input from industry peers. "I would suggest that the prospective buyer contact three suppliers for bids," he says. "The buyer should also try to visit as many shredder plants as possible, as this will allow him to pick up on the pros and cons of each manufacturer," Mullins adds.

Fellow recyclers can provide both concrete information and valuable opinions. "I would suggest the buyer try to contact other shredder operators (out of his area) to estimate costs for each size shredder and then evaluate the results," says Mullins.

Speaking on behalf of a manufacturer, American Pulverizer's Anthony agrees. "The most critical step is to have your potential customer visit or talk with existing customers to have a first-hand, impartial view of durability and support from a manufacturer."

And while determining the make and the size of the shredder are always important considerations, Anthony reminds potential shredding mill buyers to stay alert to advances in downstream sorting technology.

"When replacing a shredder, it is critical to review existing downstream [technology] so that they are sure they can handle the higher production and still get the highest recovery rates on nonferrous metals," he advises.

The author is editor of Recycling Today and can be contacted at [e-mail].