New Process to Increase Efficiency of Aluminum Recycling

A new recycling process using advanced lasers to improve automotive scrap sorting can help bring even more environmentally friendly cars and trucks to market, according to an announcement today by the auto and aluminum industries, made through their Auto Aluminum Alliance, in conjunction with the U.S. Department of Energy.

By employing lasers to identify and recover metals from scrapped vehicles, researchers have demonstrated the ability to separate cast from wrought alloys, as well as the ability to separate wrought alloys from each other at commercially viable rates.

The announcement is a potential boon to automakers and suppliers since this advanced recycling process promises to improve economic efficiency by recovering greater quantities of high-value, high-strength, high-performance aluminum from scrapped motor vehicles. Ultimately, this will allow greater use of either recycled or primary automotive aluminum -- which weigh significantly less than steel -- and will help produce even more environmentally friendly autos since lighter vehicles get higher gas mileage and emit fewer emissions.

For the 2001 model year, aluminum passed plastics and became the third most-used material in cars and trucks. Nearly 90% of automotive aluminum today is recovered and recycled. While this aluminum represents less than 10% of the average motor vehicle by weight, it already accounts for roughly half of the vehicle's value as scrap.

``Each year, automakers are using greater amounts of aluminum to help boost fuel economy and performance while maintaining safety. This advanced scrap sorting process will help ensure that automakers have a more affordable supply of recycled aluminum for the future. It also shows the great strides that can occur when the auto, the aluminum and the scrap industries work together to solve technical challenges,'' added Dr. Richard Klimisch, Vice President of The Aluminum Association.

This advanced method of separating scrap materials is being evaluated by a Belleville, Mich. metals processing firm, Huron Valley Steel Corporation. The Auto Aluminum Alliance is working with Huron Valley as part of a one-year agreement launched Aug. 24. Using a sophisticated technique called Laser Induced Breakdown Spectroscopy (LIBS), the new process uses a laser to first clean the surface of the particle by laser ablation, and then it employs a laser pulse to hit the same spot on the particle as it moves down a conveyer belt. This second laser pulse vaporizes a small amount of material from the metal's surface creating a small, highly luminescent plume of plasma, or ionized gas. To quantitatively determine the metal's chemical makeup, the plume is then analyzed by a technique called optical emission spectroscopy. Once the verification is made, the scrap is sorted by alloy on a piece-by-piece basis.

This breakthrough process is significant because it provides a practical way of sorting the scrap at commercially viable rates. Up to now, such alloys were sorted manually, which is a slow and costly process. It is estimated that the first commercial sorting center will be able to analyze and sort 100 million pounds of aluminum per year.

Increasing the efficiency of recycling aluminum does more than add value to recycling aluminum for automakers, it also reduces energy consumption. The production of recycled aluminum requires just 5% of the energy needed to produce primary materials.

The Auto Aluminum Alliance is an inter-industry collaborative research effort between USCAR and The Aluminum Association, Inc., and it is reviewing technical projects to further accelerate the use of new and improved aluminum technologies for motor vehicles.

USCAR is the umbrella organization of DaimlerChrysler, Ford and General Motors, formed in 1992 to further strengthen the technology base of the domestic auto industry through cooperative, pre-competitive research, carried out in conjunction with the U.S. Department of Energy.

Source: The Aluminum Association