Abstract:

The use of bromine-containing plastics, which have been widely used in electrical equipment as flame-retardant plastics, are now restricted by the Restriction of Hazardous Substances directive (RoHS) established in 2006. Currently, waste bromine-containing plastics are removed from the recycling flow to prevent mixing with other recycled products, and most of them are landfilled.

In this study, the use of these type of plastics for metal volatilizations has been considered to establish new effective use way. The purpose of this study is to elucidate the mechanism of metal volatilization by bromine-containing plastics from a phenomenological viewpoint. Mixed material of zinc oxide and lead oxide, which is the simulated material of steelmaking dust, was pelletized with bromine-containing plastics and was combusted in an electric furnace to observe the metal volatilization behavior. Based on the results of experiment, it was found that lead was selectively volatilized due to brominated gases generated by the combustion of bromine-containing plastics. In addition, it was also suggested that carbon monoxide gas generated by incomplete combustion of the plastics may have an intense effect on the volatilization behavior of these metals. Finally, it was confirmed that sufficient supply of air can promote the selective volatilization of lead.

Keywords: bromination volatilization, bromine-containing plastics, steelmaking dust, pelletizing, zinc, lead

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Mr. Katsuyuki Ishibashi