Alternative Method for Pyrometallurgical Recycling of EAF Dust Using Plastic Waste Containing Tetrabromobisphenol A

摘要

Tetrabromobisphenol A (TBBPA) is the largest volume brominated flame retardant (BFR) in production to- day, used in more than 70% of the world’s electronic and electric (E&E) appliances as well as in many plastics, tex- tiles and so forth. There is constant growth in the produc- tion of such products and they become obsolete quickly, this generates huge amounts of BFR-containing wastes and causes significant problems for their safe disposal and recy- cling. The most common way to use them is in thermal process- ing. TBBPA easily decomposes during this process, gen- erating significant amounts of gaseous HBr. The HBr is present mostly in the flue gas and can act as a bromination agent for selective bromination-evaporation of heavy metals present in co-combusted metallurgical dusts, like zinc and lead-rich electric arc furnace (EAF) dust. EAF dust, though classified by various government regu- latory agencies as hazardous waste, is considered a valu- able secondary raw material in the production of zinc. The worldwide generation of EAF dust represents a possible re- covery of approximately 1.4 million tons of zinc. Thus the co-combustion of the mixed wastes can be chance for simul- taneous recovery of both, energy from waste plastics and inorganic fractions from the dust, while the separated iron oxide-rich residues can be used as iron-making and steel- making resources. In this study, a laboratory-scale furnace was used to inves- tigate (1) the reactivity of zinc with the product of the ther- mal decomposition of TBBPA, and effect of (2) temperature on the efficiency of the bromination and vaporization pro- cesses.