Brominated Dioxins & Furans
Brominated flame retardants in end-of-life management are not problematic regarding formation of brominated dioxins/furans.
The data demonstrate that under the conditions employed a typical HIPS/Sb2O3/DecaBDE plastic can be recycled at least five consecutive times without debromination of the flame retardant DecaBDE to lower brominated diphenyl ethers and fully maintaining the plastics fire safety. The reprocessed (recycled) plastic was found to fully comply with the German Chemicals Banning Ordinance on the formation of PBDD/Fs.
A high impact polystyrene (HIPS) plastic, flame retarded with decabromodiphenyl ether (DecaBDE) and antimony trioxide has been repeatedly processed and the amount of debromination of the flame retardant and possible formation of PBDD/F was monitored . The amount of PBDD/F formed during processing of plastic/FR combinations strongly depends on the processing conditions, namely the processing temperature and the purity of the flame retardant. The conditions employed in this study represent conditions typically used for the processing of HIPS/Sb2O3/DecaBDE formulations.
- Studies of interest
- Benefits in terms of energy recovery and recycling goals
- Comments on Greenpeace technical background document on mixed halogenated dioxins & furan
Studies of interest:
-
GfA Gesellschaft fur Arbeitsplatz- und Umweltanalytik mbH. 1999 "Determination of polybrominated diphenyl ethers and PBDD/Fs during the recycling of high impact polystyrene containing decabromodiphenyl ether and antimony oxide"
-
Pinkerton et al. 1989. A preliminary report on the investigation of the comparative toxicity of combustion products of high impact polystyrene with and without decabromodiphenyl oxide/antimony trioxide as a flame retardant using 2,3,7,8-tetrabromodibenzo-p-dioxin and 2,3,78-tetrabromodibenzofuran as positive controls. Chemosphere 1-6:1243-9
-
Hardy et al. 1990. 2,3,7,8-Tetrabromodibenzofurn (TBDF): 4 week subchronic study in the rat. Organohalgoen Compounds 1:313-6
-
Ivens et al. 1993. Subchronic toxicity of 2,3,7,8-tetrabromodibenzo-p-dioxin in rats. Toxicology 83(1-3):181-201
-
Ranken et al. 1994. Definitive study of the determination of polybrominated dibenzo-p-dioxins and polybrominated dibenzofurans in decabromodiphenyl oxide and tetrabromobisphenol A. Bull Soc Chim Belg. 103(5-6):219-33 [European Section].
-
PBDD/F in a commercial polymer extrusion facility. 1988. Reported in WHO 1994.
-
McAllister et al. 1990. Analysis of polymers containing brominated dipenyl ethers as flame retardants after molding under various conditions. Chemosphere 20(10-12):1537-41.
-
Tondeur et al. 1990. Analytical procedures for the determination of polybrominated dibenzo-p-dioxins and dibenzofurans in tetrabromobisphenol A and 1,4,6-tribromophenol. Organohalogen Compounds 2:373-6.
Benefits in terms of energy recovery and recycling goals
Currently, there is an increasing demand for the recycling of plastics; this is in large part because of rising oil prices - oil being the raw material needed for producing plastic. Recycling plastic also has a high potential for energy recovery, because it is energy efficient, all of which lowers.
A practical example this type of energy recovery is the Umicore integrated metals smelter. Integrated metal smelters offer several advantages for recycling WEEE plastics containing flame retardants. The metal content of the waste can be recovered for recycling: copper, tin, lead, nickel, arsenic, antimony, indium, silver, gold or palladium. Meanwhile, the polymer content serves as an energy source and reducing agent for the smelter process (partially replacing coke consumption). In the end, all contaminants are eliminated in a high temperature smeltering process and in the existing smeltering emission controls systems.
Study results confirm the advantages and feasibility of this type of energy recovery for WEEE plastics with higher contents of precious metals, in particular with plastics that may contain flame retardants (with a content of bromine, antimony, phosphorus, aluminium, magnesium, nitrogen or other elements). Umicore is specifically focused on the recovery of precious metals and therefore WEEE fraction from IT equipment is of great interest.
For more information on technical recycling solutions click here.
