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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. [ABSTRACT FROM AUTHOR]

Surface ignition is the first and also the important step for iron ore sintering, which provides the initial source of energy to trigger the whole reactions. This investigation mainly focused on revealing the relationship between surface ignition and sintering performance, and elucidated the deep mechanism. Results indicate that the quality of sinter in the surface layer can be effectively improved by adjusting the ignition parameters. The preferred ignition parameters include ignition temperature of 1050 °C, ignition duration of 1 min and heat preservation of 1−2 min. The function mechanism of improved sinter quality is attributed to the increased high temperature duration for minerals melting, the enlarged melting zone, and the decreased cooling velocity. These changes facilitate the formation of enough adhesive phase of calcium ferrite, more of which generated in acicular morphology with high mechanical strength. Optimizing the ignition process reduced the solid fuel consumption due to the improved sintering performance, which then decreased the emission of NO and SO 2. The research findings are of great significance for providing a guide for the design of desirable ignition system and making further contributions to energy conservation and emission reduction during sintering. [ABSTRACT FROM AUTHOR]

• Injection parameters of H 2 -rich gas over sintering process were optimized. • Experiment and numerical simulation were used to elucidate function mechanism. • A novel method on hydrogen-rich energy application in practical plants was developed. H 2 -rich gas has been widely regarded as a promising energy to substitute fossil energy in iron ore sintering process for CO 2 reduction. This investigation mainly focused on researching the influences of H 2 -rich gas injection parameters over sintering bed on sintering performance, and elucidated the potential function mechanism through both experiment and numerical simulation. Results indicated that increasing injection concentration and prolonging injection time within a proper range improved sinter quality, and the recommended value was 0.6∼0.8 % and 8 min, respectively. Injecting H 2 -rich gas at earlier sintering stages achieved greater improvement in sintering quality compared with the ones injecting at later sintering stages, and the recommended injection area was 5∼13min. Both experiment and numerical simulation results indicated that injecting H 2 -rich improved the thermal patterns of sintering bed, with extended high-temperature areas for increasing the generation of high-strength calcium ferrite. Especially when injecting H 2 -rich gas under the recommended parameters, the heat distribution in sintering bed was optimized and the sintering quality of upper sintering layer was obviously improved. Finally, an injection method for guiding the industrial application with its essence to inject H 2 -rich at earlier sintering stages was proposed. The research findings provide a promising way for the efficient utilization of clean energy in iron ore sintering plants. [ABSTRACT FROM AUTHOR]