Thermal Analysis on the Pyrolysis of Tetrabromobisphenol A and Electric Arc Furnace Dust Mixtures
- PDF / 3,655,846 Bytes
- 16 Pages / 593.972 x 792 pts Page_size
- 94 Downloads / 181 Views
I.
INTRODUCTION
STEEL can be considered as the most recycled material, with more than 650 Mt tonnes recycled annually[1] According to the World Steel Association,[1] electric arc furnaces produce about 29 pct of worldwide steel, of which most is produced from recycled material. This recycling process generates enormous amounts of electric arc furnace dust (EAFD). It is estimated that a tonne of molten metal produces about 11 to 20 kg of EAFD.[2,3] This implies that about 8 to 13 Mt of EAFD is generated annually. This dust is considered a secondary source for zinc; it contains 7 to 40 pct zinc depending on the proportion of galvanized steel scrap
MOHAMMAD AL-HARAHSHEH, AWNI AL-OTOOM, and MUHANNAD AL-JARRAH are with the Chemical Engineering Department, Jordan University of Science and Technology, Irbid, 22110, Jordan. Contact email: [email protected] MOHAMMEDNOOR ALTARAWNEH is with the School of Engineering and Information Technology, Murdoch University, Murdoch, WA 6150, Australia. SAM KINGMAN is with the Faculty of Engineering, University of Nottingham, Nottingham, NG7-2RD, UK. Manuscript submitted July 3, 2017.
METALLURGICAL AND MATERIALS TRANSACTIONS B
recycled.[2,4] Therefore, zinc recovery from EAFD is of prime importance in terms of energy efficiency and resource conservation. The only industrial process currently employed for zinc recovery from EAFD is the Waelz Kiln process. This technology is applied in 30 to 35 locations across the world in order to recycle about 45 pct of EAFD.[5] The attempts to use alternative technologies for recycling EAFD, such as hydrometallurgical methods, have failed so far due to technical, environmental, or economic constraints. Recently, recycling EAFD combined with plastic waste has been a thematic research topic with a number of reported studies. This technology uses the presence of halogens in plastics, such as chlorides in PVC and bromides in brominated flame retardant (BFR) materials, to react with the metal oxides present in the EAFD. Upon decomposition of these plastics, the corresponding hydrogen halides of HCl or HBr are released, converting metal oxides into chlorides or bromides at moderate temperatures [below 573 K (300 C)]. Metal halides formed can be either heated further to evaporate them[4,6–9] or leached with water from the pyrolysis residue, as demonstrated in recent studies.[10–13] Understanding the interaction between the EAFD and PVC/BFRs is important for process development, especially the thermodynamics of pyrolysis. To the
authors’ best knowledge, the literature provides no account of the thermodynamics underpinning the pyrolysis of EAFD-BFR/Tetrabromobisphenol A (TBBPA) mixtures, although one can find several publications on the interaction between metal oxides or EAFD with TBBPA.[4,8,9,12,14–16] Likewise, quantum chemical calculations have mapped out reaction pathways between Fe2O3 (a minor constituent in EAFD) with products from thermal decomposition of TBBPA.[17] TBBPA is considered as one of the most important feed materials for the manufa
Data Loading...
