Bromine removal from resin particles of crushed waste printed circuit boards by vacuum low-temperature heating

摘要

y Uncontrolled dumping and incineration of resin particles of waste printed circuit boards had caused serious pollution due to the contained brominated flame retardants. High-temperature vacuum pyrolysis was proposed to treat the resin particles. However, due to the generation of brominated gases and solid floc, high-temperature vacuum pyrolysis reproduced more hazardous wastes. In this paper, resin particles of crushed waste circuit board were processed by vacuum heating at the temperature of 300 degrees C and condensation at 180 degrees C. Resin particles were converted into residue and oil with the mass ratios 84.0 wt% and 16.0 wt% respectively. Content of organic bromine in residue was reduced to 0.082 wt%. Meanwhile, morphology of resin in residue was basically unchanged, which could be directly recycled as the filler for building materials. About 95.4 wt% of bromine in resin particles was transferred to oil. These results achieved the reduction of the hazardous wastes. Compared with the high-temperature vacuum pyrolysis, low-temperature heating not only reduce energy consumption, but also reduce the generation of toxic products. This paper might be the first time to report low-temperature heating of resin particles of waste printed circuit boards. This study contributed a novel technology to remove bromine from brominated substrates. (C) 2020 Elsevier Ltd. All rights reserved.