(241b) Chemical Recycling of Mixed Plastics in the Electronic Waste Using Solvent-Based Processing

Currently, less than 20% of e-waste is recycled in the United States because the options for making high‐value products using mixed waste are either limited or too costly. To address this concern, the aims of this study are: 1) to achieve cost parity for secondary materials, 2) to enable cross-industry reuse of recycled e-waste, 3) to reduce primary e-waste consumption and increase secondary by 30%, 4) to identify major plastic and metal compositions in the electronics shredder residue (ESR), and 5) to formulate solvents and process conditions to separate 90% of the plastics targeted from consumer shred ESR. In this study, a heterogeneous electronic scrapper residue (ESR) feedstock, in which the valuable aluminum, magnetic components, and hazardous battery material were hand-sorted and collected. The major compositions in the ESR were characterized. It is found that 25% is plastic, 6 % is rubber, 27% is PCB (Printed Circuit Board), 23% is wired coatings. In the plastic portion, polystyrene (PS, 40 wt.%), acrylonitrile butadiene styrene (ABS, 25 wt.%), and styrene-acrylonitrile (SAN, 9wt.%) are identified as the major plastic using Fourier transform infrared spectroscopy (FTIR). Next, selective mixed solvents are screened using the Hansen Solubility Parameter Theory in Practice (HSPiP) software for dissolving PS and ABS. The HSPiP gives 3 dimensions: dispersion (D), polar (P), and hydrogen bonding (H) are intermolecular forces that when square and summed will give you the squared of the cohesion energy density of a solvent to a solute. Our preliminary prediction results using HSPiP software indicate Butyl Benzoate and Cyclohexanone are suitable to optimize the dissolution processes for waste ABS, PS-based (including polystyrene and high impact polystyrene), and styrene-acrylonitrile (SAN). It is expected that results from this project will prove the potential of solvent-based processing to produce secondary materials (plastics and metals) from e-waste for cross-industry reuse.