Optimisation of FeO in iron ore sinter at JSW Steel Limited

Abstract

Coke breeze is the most common fuel used in sintering, and its usage depends on the alumina content and fineness of the sinter mix. The coke breeze consumption in the JSW Steel Limited sinter plant was high compared to many other sinter plants in the world, and as there was a local shortage, optimisation in the sinter plants was necessary. FeO is an indicator of the thermal state of the sintering process and is employed as a quality control tool at many plants. Laboratory pot sinters were made, and the variation in FeO was affected by varying the amount of coke breeze in the green mix from 55 to 85 kg t⁻¹ of sinter. The produced sinters were evaluated with respect to productivity, strength (tumbler index), reduction degradation index (RDI), reducibility and microstructural phases in the FeO range between 6·2 and 14·8%. It was found that the sinter with FeO range of 8·60–9·88% showed higher productivity and higher strength with desired RDI of ⩽27% and reducibility of >60%. Analysis of plant data has revealed that the sinter with FeO of 8·5–10·0% showed higher productivity, higher strength and lower RDI.