PREMISE: Exploratory Research: An Alternative Process Model for Printed Circuit Board Recycling

Texas Tech University, Lubbock TX

Investigators

Abstract

The objectives of this Product Realization and Environmental Manufacturing Innovative Systems (PREMISE) Exploratory Research project are: (1) To conduct exploratory research into the feasibility of an alternative PCB recycling process based on cryogenic decomposition of the PCBs; (2) To establish an interdisciplinary research team that can develop a long-term collaboration that builds on the understanding developed in this project; (3) To evaluate the proposed recycling process against traditional PCB recycling processes in terms of recycle rate economics, energy consumption, and environmental performance; and (4) To examine the feasibility of reusing plastics in the proposed recycling process. The proposed recycling process is cryogenic decomposition of the PCBs. The process takes advantage of the fact that at very low temperatures, polymeric materials become highly brittle. In addition, the residual stresses set-up in the PCB resins due to thermal expansion mismatch between the polymers and other materials on the PCB is expected to lead to a better separation than might otherwise be possible simply due to the embrittlement of the plastics. Actual laboratory experiments will be performed using a cryogenic test system. Wide diffusion of electronic equipment and shortening of product lifecycles have caused a serious problem: how to deal with large quantities of end-of-life or obsolete electronic equipment. While there are various technical challenges for electronic product recovery and recycling, this research focuses on printed circuit boards (PCBs) or printed wiring boards (PWBs). PCBs are primary components in many electronic products built for both military and commercial applications. Due to their complex construction and the consequent complicated mixture of materials, PCB recycling presents a serious challenge to today's industry. The rich content of precious metals provides a strong economic justification for materials recovery and recycling. On the other hand, large amounts of toxic components and fiber-reinforced polymers create difficulties for recycling and adverse environmental impact.