Vehicle Recycling Partnership Plastics Separation Pilot Plant

Separating plastics at high concentrations from waste streams has been a challenge because many conventional separation methods depend on material density or employ organic solvents. Many plastics have overlapping densities and, therefore, could not be separated from each other based on density differences alone. Organic solvents pose environmental risks. Argonne has developed a process for separating individual polymers and groups of compatible polymers from various polymer rich waste streams. The Argonne process includes froth flotation techniques to separate materials that have over lapping densities. Argonne's process successfully produced recycled acrylonitrile-butadiene-styrene (ABS) with a purity of greater than 98% from waste generated by shredding home appliances. The process was also successful in separating ABS and polystyrene from electronics scrap.

In 2003, Argonne, the U.S. Department of Energy, the Vehicle Recycling Partnership of USCAR (a partnership of Chrysler, Ford Motor Co. and General Motors Corp.), and the American Chemistry Council/Plastics Division announced the signing of a five-year, multi-million dollar cost-shared Cooperative Research and Development Agreement (CRADA) designed to enable cost-effective recycling of end-of-life vehicles. Much of the work is conducted at Argonne's pilot plant recycling facility.

As part of the pilot plant, Argonne designed, built and tested a 1000 pound per hour, six-stage plastics recycling facility. The new recycling process works for just about all mixtures of plastics generated by industry. The plant recovers up to five products from a single waste stream. The new plant advanced the state of the art because it can be used to separate plastics with overlapping density ranges — and it can do so cost-effectively. Data produced from running the plant were used to design a full-scale (5000 lb/hr) flotation module which is now part of the pilot plant.

The process has been used to recover polyolefins from automobile shredder residue at 95% concentration. It also recovered, from shredder residue, styrenics, rubber and residual metals.

June 2008