Identification the Content of the Windbox Dust Related to the Formation of PCDD/Fs during the Iron Ore Sintering Process

Abstract

This study measured the contents of the ionic and elemental constituents, and the chemical compounds containing in windbox (WB) dusts collected from a commercial iron ore sintering plant, then the results were used to identify possible PCDD/Fs formation pathways in the WB. We found that the abundance in both KCl and NaCl may provide a suitable condition for de novo synthesis of PCDD/Fs in the WB. Al, Fe, K, Ca, and Pb were the top five contents in WB16 dusts, but the co-existence of the above five metal contents warrants the need for further investigation on their roles in PCDD/F formation processes in the future. Although a low concentration of Cu was detected, it might be of importance to PCDD/Fs formation inside the WB. A total of 29 chemical compounds were identified. Among them, several oxygenated organic compound might be associated with PCDD/F formations at the beginning stage, but the roles of aromatic oxygenates on the formation of PCDD/Fs required further investigation. Finally, possible de novo synthesis pathways of PCDD/Fs were proposed based on the above findings. However, the above pathways are required further laboratory studies for validation before possible formation suppression approaches can be determined.

An Overview of PCDD/F Inventories and Emission Factors from Stationary and Mobile Sources: What We Know and What is Missing

“…The raw material can contain substances that have been reported to be essential or facilitate the formation of PCDD/Fs e.g., chlorine, organic compounds and metal catalysts like Cu (Cieplik et al, 2003). However, though the current understanding is that PCDD/F are majorly formed within the sinter bed, an analysis of the dust particles in wind boxes revealed that it contains significant amounts of Cl and unburnt carbon (Tsubouchi et al, 2006;Kuo et al, 2011) making it a potential area for PCDD/F formation. The contribution from each region to the total PCDD/Fs emitted is still not fully investigated and understood.…”

Fate of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans during the Thermal Treatment of Electric Arc Furnace Fly Ash

“…In addition, the total PCDD/F I-TEQ emissions had adverse health effects on employees in the affected workplaces during the treatment process (Wang et al, 2003a;Wang et al, 2010a). Moreover, the Waelz process increased the fraction of low-chlorinated congeners, because it is more difficult to decompose the aromatic rings of PCDD/Fs than to dechlorinate from the high-chlorinated congeners to the lower ones Li et al, 2007c;Li et al, 2008;Shih et al, 2008;Shih et al, 2009;Yu et al, 2010;Chiu et al, 2011;Kuo et al, 2011). Therefore, the PCDD/F formation, emission, transportation, reduction and risk assessment for the Waelz process need to be evaluated, (Huang et al, 2011), and to treat EAF fly ash needs to be developed.…”

Effect of Temperature and CaO Addition on the Removal of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Fly Ash from a Medical Waste Incinerator

“…Many studies have focused on PCDD/F emissions in thermal reaction facilities, including sinter plants, electric arc furnaces, secondary aluminum smelters, coal-fired power plants, and crematories (Rappe, 1992;Wang et al, 2003a;Wang et al, 2003c;Chen et al, 2004;Lee et al, 2004;Lee et al, 2005;Lin et al, 2007;Lin et al, 2010;Chen et al, 2011;Chiu et al, 2011;Kuo et al, 2011). Generally, the combustion temperature and chlorine content of raw materials plays an important role in PCDD/F formation (Lee et al, 2003;Wang et al, 2003b;.…”