Investigation on the application of by-product steam in iron ore sintering: performance and function mechanism

The combustion-supporting effect of steam to coke breeze in sintering has the potential to improve sinter quality and reduce pollutants emissions. The results show that increasing the by-product steam injection concentration (0.32-0.47vol%) and prolonging the injection time (5 min) within a proper range (10-15 min) can improve sinter quality. 2.13kgce/t_-sinter of the fuel consumption was decreased by reducing coke breeze usage from 5.60 to 5.45% under the recommended parameters, with 15.16% decrease of CO in sintering waste gas. By comparing experimental data with thermodynamic calculations, although the reaction between CO and steam can reduce CO emission and generate H₂, steam tends to react with coke breeze to generate H₂ and CO (react at 674℃), and OH radical produced by H₂ which can reduce the activation energy of CO oxidation reaction is the key to reducing pollutant emissions. The potential economic benefit of steam injection technology was calculated based on a 360m² sintering machine (the annual sinter output is 3.2million tons), excluding the equipment modification and steam injection cost of $300,000; a profit of $737491.2 per year or 0.23 dollars per ton sinter can be achieved. Therefore, low-carbon and cleaner iron ore sintering production can be realized through applying by-product steam.