Bromine fixation by metal oxide in pyrolysis of printed circuit board containing brominated flame retardant

Pyrolysis study of a printed circuit board (FR-4 type, epoxy resin reinforced by glass fibers) under the presence of metal oxide, such as ZnO, Fe2O3, La2O3, CaO and CuO, has been carried out in the view of the emission control of waste electrical and electronic equipment (WEEE) containing brominated flame retardants by metallurgical wastes like slags and dusts. The oxide content is of 2–10 mass% to the printed circuit board on the basis of the stoichiometric reaction of oxide and bromine to the corresponding metal bromide or oxybromide. It has been revealed that the formation of hydrogen bromide and brominated organic compounds is significantly suppressed by the addition of ZnO and La2O3. The bromine fixation ability of various oxides is compared and discussed.

► A printed circuit board is pyrolyzed under the presence of metal oxide.
► Examined oxides include ZnO, Fe2O3, La2O3, CaO and CuO.
► The oxide content is of 2–10 mass% to the printed circuit board.
► ZnO and La2O3 suppress the yield of HBr and brominated organic compounds.
► The mechanism is considered as the reaction of oxide and flame retardants.