NEW YORK Aluminum scrap turnings are increasingly being compressed into pucks to boost recovery rates, traders and recyclers told AMM.
A growing numbers of producers are installing pucking machines, with high-grade, 7000-series and 6000-series turnings said to be the most commonly traded, aluminum scrap traders said.
The main advantage of pucked turnings is said to be their reduction is moisture content, which boosts recovery rates and removes the need for drying.
"I think the briquettes typically arent as dry," one aluminum scrap trader said. "If they run over 4- to 5-percent moisture, then you have to run them though the crusher and dryer. But pucks are so dense that you can direct charge those, which saves on processing costs. Its almost like melting a solid."
Reduced moisture also increases the weight of the metal being shipped, achieving greater economy in freight.
"If youve got 40,000 pounds of loose turnings, youve got a lot of dead weight," a second trader said.
Pucks are also easier to ship, some market sources said.
"You can put them in a box and not have to store loose, wet turnings," the second trader said. "That increases the value of the finished product."
However, one trader said he refuses to buy pucks, citing concerns over whether the recovery rates have been overstated.
"You need to be careful with the furnace you introduce (the pucks) to," the trader said. "They seem to do better with rotary furnaces than reverb furnaces. In the reverbs, they tend to float when you need to get them below the molten line."
Even though most consumers have tried pucks and some swear by them, "others wont touch them because they cant get them under the molten line and get the proper recoveries," the trader said. "If something has 4- to 5-percent moisture, thats going to stick to the material and stay in there. And the colder the weather, the more likely it will stay on there."
The first trader also cautioned against pucks that use a binding material. "Ive seen some pucks with a recovery of 70 percent because of the binder in there," he said.