Recycling asphalt shingles with a portable plant that traditionally grinds wood is no simple task, says Todd Dunderdale, vice president of marketing at Komptech Americas. The equipment on the market generally isn’t designed to recycle shingles specifically. But recyclers have improved their shingle-recycling processes over time through trial and error and identified equipment that does the job most efficiently.
“We have a big customer in Kansas City who has learned through trial and error using the Crambo, a low-speed shredder,” Dunderdale says. “They’ve been trying to use high-speed systems, but we use a different method – a low-speed shredder – and we don’t have to add water.”
According to Dunderdale, most recyclers recycle asphalt shingles using high-speed wood grinders.
“The mill’s spinning at 1,200 rpm on average,” he says. “They add water to it, but that’s not what the asphalt company (customer) obviously likes because it lowers the temperature of the material.”
The Crambo’s shaft speed is about 35 rpm, Dunderdale adds. He says a Crambo shredder can process the same shingle tonnage as a high-speed grinder – and the material produced is dry.
“There’s no one-pass solution,” Dunderdale says. “We get 65 to 75 percent finished in one pass with no water. It’s dry to 3/8-in. minus.”
Dunderdale adds that most customers using a Crambo to shred shingles use a star screen in tandem with it.
“We use a 2-in. screen in our Crambo, and eventually we get a finished product,” he says.