Reclaiming Bromine, Antimony, and Carbon Species from Plastics Containing Brominated Flame Retardants and Antimony Trioxide

It is estimated that more than half of discarded electrical and electronic equipment is incinerated, landfilled, or smelted to recover the metals. However, these pathways are not optimal with respect to environmental footprint and do not facilitate the full recovery of all valuable elements in the plastics. In the case of plastics using brominated flame retardants (BFR) and antimony synergist, more value could be extracted if bromine, antimony, and hydrocarbons could be reclaimed for reprocessing, a circular strategy that significantly reduces the negative environmental impacts of these waste streams, such as the formation of brominated and mixed-halogenated dibenzo-p-dioxins and dibenzofurans or dispersion of BFR into the environment in dust particles. These considerations have prompted us to develop new technologies that recycle bromine, antimony, and hydrocarbons from BFR-containing plastics in environmentally safe operations that are scalable to industrial through-puts and are economically viable. Our approach is to pyrolyse BFR-laden plastics mixed with inexpensive catalysts that constitute waste streams themselves. These catalysts comprise the electric arc furnace dust supported on aluminosilicate particles; the latter arise as by-products of refining lithium minerals. We have applied density functional theory to understand the possible reaction pathways, acquire governing electronic attributes, and compute the kinetic rates for the reactions between BFR and the catalysts.