Aluminum innovation cuts waste
Pittsburgh Business Times - by Cesca Antonelli
OAKLAND -- Solid waste has been an obstacle to productivity and profit in the aluminum industry for a century now, but local researchers may have found a way to melt the problem down.
A new smelting technology, being pioneered by a Carnegie Mellon University-sponsored center, has increased the aluminum yield of test batches while nearly eliminating waste.
Dross is a waste byproduct produced when chips of aluminum scrap are remelted in large baths to make clean aluminum for new products. The process is known as smelting.
The new hardware, known as a low-dross melter, works on the same basic principles as traditional smelters.
"We had found a problem in the aluminum industry that required a solution," said Frank Kemeny, president of Grand Island, N.Y.-based Process Engineering Dynamics, an engineering firm that worked with CMU researchers in the effort.
"The problem was that (used scraps of) aluminum weren't being dealt with in an environmentally friendly and efficient manner. So we looked for an alternative method."
Two units have been installed so far (one in Cleveland and one in Los Angeles), and Mr. Kemeny said there are 40 inquiries right now. He expects to start $2.5 million worth of projects this year.
In the low-dross method, the heat for smelting is provided by high-voltage graphite electrodes, instead of the traditional gas-fired oven.
Electric-powered furnaces are common in modern steelmaking, but they have been slow to catch on in the production of aluminum.
About half the steel made each year comes from such electric furnaces. But nearly 90 percent of the 10 million tons of aluminum produced in the United States annually is made using conventional, gas-fired furnaces.
The Electric Power Research Institute at CMU had done some lab work on the use of electricity and its effect on dross production. Mr. Kemeny said the results looked promising, and the EPRI offered funding to develop the technology.
There are other differences in the new unit's design as well, intended help separate aluminum and air. When the aluminum being processed is exposed to air, oxidation creates dross, causing waste and trimming production. The technology also uses argon gas, which prevents oxidation.
As much as 10 or 15 percent of a melt using traditional methods can end up as dross, said Bob Schmitt, associate director of the EPRI's Center for Materials Production, which helped developed the technology.
"Aluminum has a tremendous affinity for air and oxidizes rapidly," he said. "We can prevent much of that."
In the new method, any dross created can be captured and processed.
These differences could translate into profits for aluminum makers.
The new technology has a yield of nearly 99 percent, based on nearly a year's worth of tests done at Wabash Alloys in Cleveland.
In a typical smelter, this technology would produce an extra half-ton of aluminum every hour. Another unit will be installed this year at TIMCO in Los Angeles, and a spokeswoman for local aluminum giant Alcoa said the company was monitoring developments.
The new approach has caught national media attention as well. The low-dross process won an "R&D 100 Award," sponsored by R&D Magazine. The awards are given for the 100 most significant technological innovations of the year.
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