In June 1997, the Vehicle Recycling Partnership (VRP) and the American Plastics Council (APC) asked MBA Polymers to conduct a study to determine the technical and economic feasibility of recovering metals and plastics from end-of-life radiator end caps (RECs). The VRP worked with the Institute of Scrap Recycling Industries (ISRI) to obtain samples of RECs from two metal recycling companies, SimsMetal America and Aaron Metals.
MBA performed its standard Recyclability Assessment on the materials, which included a detailed density and material characterization study and an actual processing study using its pilot processing line. It was found that the polyamide from RECs could be recovered in reasonably high yield and purity using tight density separations.
The recycling of the REC samples used for this study generated about 40% nonferrous metal, 19% mixed ferrous and nonferrous metal and about 20% polyamide flakes. The composite recovered material values were estimated to be about $0.15 to $0.25 per pound of incoming material, including subtraction for disposal cost of unrecovered material. The range is due to material value ranges for the nonferrous, ferrous/nonferrous mix, and polyamide fractions.
MBA believes that the yields could be improved to about 52%, 6%, and 29%, for the nonferrous, ferrous, and plastic fractions, respectively, with minor processing changes in a production operation. These changes would significantly improve the estimated composite recovered material values to between $0.19 and $0.32 per pound of incoming material.
The testing of the polyamide material demonstrated that it could be blended with virgin material to create a 25% post-consumer recycled content material exhibiting very good properties (near that of virgin). A significant drying challenge was encountered, however, by all three of the laboratories testing the material. The material had to be dried much longer than virgin material to prevent outgassing during extrusion, presumably due to absorbed coolant that is more difficult to evaporate than water. It is not clear if the residual coolant leads to property degradation during melt processing, therefore, extensive drying may not be an absolute requirement. Vented extrusion might be a possibility.
Additional testing with larger volumes is recommended to better determine processing economics, investigate coolant extraction techniques, and to generate material for additional evaluation and possibly part molding trials.