Recycling of Waste Flame-Retarded ABS (Acrylonitrile Butadiene Styrene) Plastics into Bromine, Antimony and Hydrocarbons

Brominated flame retardants (BFR) reduce the flammability of plastics when applied together with antimony trioxide as a synergist. The effect is significant and noticeable in delaying ignition. Statistics of fire fatalities succumb both from the widespread application of flame retardants, especially BFR, and declining smoking. Unfortunately, there is no commercially viable technology to recycle bromine and antimony-laden plastics, except for energy recovery from incineration. In this situation, governments around the globe may proceed to ban plastics containing BFR. Viable technologies to recycle BFR-retarded plastics into bromine, antimony and high-value oils or monomers are urgently needed. This PhD project aims to investigate the efficiency of calcium hydroxide in removing bromine and antimony from oil and fixing them in the solid residue, in a pyrolysis-based process. We focus on recycling plastics of brominated acrylonitrile butadiene styrene (ABS). Our target is to decrease the concentration of bromine and antimony in the pyrolysis oil to less than 1 ppm, and to produce separate streams of bromine and antimony, thus fostering a circular economy. Our technology needs to be energy-efficient and environmentally friendly and be able to handle varying compositions of bromine and antimony in plastic waste. Finally, to gain acceptance from the community, our process needs to produce high purity and high-value oils or monomer mixtures, readily usable in a range of applications.