Promoter material and inhibitor material for dioxins formation in sintering process

Abstract

Raw materials of the iron ore sinter contain certain amounts of carbon and chlorine sources, which are indispensable elements to form dioxins. It has been also pointed out that the properties and contents of the solid fuels and chlorides in the raw mixture significantly affect the dioxin emissions during the iron ore sintering process. However, their control is not always practically possible because coke is the main fuel of the process and chlorides are unavoidable impurities contained in the raw materials. It has been reported that some substances act as catalysts to promote the formation of dioxins or as inhibitors to suppress it, although the detailed mechanisms have not been comprehensively understood yet. In the present study, the effect of the various additives to the raw mixture was examined by some series of sinter pot tests. Especially, copper compounds, e.g., metallic copper, copper oxide and copper chloride, were employed as catalysts and ammonia and its relating compounds to release the active nitrogen components in elevating temperatures, e.g., ammonium sulfate, urea, ethylene-di-amine and mono-ethanolamine, were acted as inhibitors. Further, the effects of the kinds of lime resources and iron ores on the dioxins emissions were studied.