We conducted thermal tests using the reagent tetrabromobisphenol A (TBBPA) and various Pd compounds to study the chemical forms of Pd obtained during the pyrolytic and oxidative decomposition of TBBPA. Thermal testing...We conducted thermal tests using the reagent tetrabromobisphenol A (TBBPA) and various Pd compounds to study the chemical forms of Pd obtained during the pyrolytic and oxidative decomposition of TBBPA. Thermal testing was conducted in an electric furnace at temperatures of 280°C - 800°C in an Ar or Ar-O2 (5%) atmosphere for a heating period of 40 min. Scanning electron microscopy-energy dispersive X-ray spectroscopy results revealed that Pd bromide was formed in the mixture of TBBPA and PdO after heating to 450°C in the Ar atmosphere. In addition, thermogravimetry-differential thermal analysis showed that as the heating temperature was increased from 350°C to 730°C, weight loss occurred at a nearly constant rate, indicating that Pd bromide decomposed in this temperature range.展开更多
Thermal degradation of a FR-4 type printed circuit board, PCB, containing brominated flame retardant has been studied both in inert and oxidative atmosphere for the emission control of harmful brominated compounds. Th...Thermal degradation of a FR-4 type printed circuit board, PCB, containing brominated flame retardant has been studied both in inert and oxidative atmosphere for the emission control of harmful brominated compounds. The presence of oxygen in atmosphere resulted in the reduction of the yield of hydrogen bromide, one of the major brominated compounds in thermal treatment, and in the enhancement of the formation of bromine and hypobromous acid. The intentional addition of zinc oxide to the PCB powder sample gave rise to the fixation of Br as zinc bromide. It also resulted in the promotion of the release of brominated compounds in comparison to the case of pure PCB. Thus, the addition of the oxide can be a benefit with respect to the bromine fixation and the kinetics of thermal treatment of PCB as well as metal recovery.展开更多
文摘We conducted thermal tests using the reagent tetrabromobisphenol A (TBBPA) and various Pd compounds to study the chemical forms of Pd obtained during the pyrolytic and oxidative decomposition of TBBPA. Thermal testing was conducted in an electric furnace at temperatures of 280°C - 800°C in an Ar or Ar-O2 (5%) atmosphere for a heating period of 40 min. Scanning electron microscopy-energy dispersive X-ray spectroscopy results revealed that Pd bromide was formed in the mixture of TBBPA and PdO after heating to 450°C in the Ar atmosphere. In addition, thermogravimetry-differential thermal analysis showed that as the heating temperature was increased from 350°C to 730°C, weight loss occurred at a nearly constant rate, indicating that Pd bromide decomposed in this temperature range.
文摘Thermal degradation of a FR-4 type printed circuit board, PCB, containing brominated flame retardant has been studied both in inert and oxidative atmosphere for the emission control of harmful brominated compounds. The presence of oxygen in atmosphere resulted in the reduction of the yield of hydrogen bromide, one of the major brominated compounds in thermal treatment, and in the enhancement of the formation of bromine and hypobromous acid. The intentional addition of zinc oxide to the PCB powder sample gave rise to the fixation of Br as zinc bromide. It also resulted in the promotion of the release of brominated compounds in comparison to the case of pure PCB. Thus, the addition of the oxide can be a benefit with respect to the bromine fixation and the kinetics of thermal treatment of PCB as well as metal recovery.
