Development and application of a novel fluxing compound for improving sintering performance of high alumina iron ore

ABSTRACT

Blast furnaces (BF) ferrous burden consist of sinter (>50%) with rest being pellets and lump ore. Good sinter quality is necessary for efficient BF operation which depends on iron ore quality and its gangue. In gangue, alumina has a strong influence that adversely affects product quality and productivity. To address those effects this study presents a two-stage method. It involves the development of a novel low temperature melting synthetic flux i.e. Iron Rich Calcium Ferrite (IRCF) at Stage-1 and its addition in high alumina sinter feed at stage-II. Microstructural and dilatometry studies show that IRCF encourages the formation of silico-ferrite of calcium and aluminum (SFCA-1). The IRCF addition (6% max) in the high alumina (3.1%) sinter feed improves the Tumble index by 4.7 points, lowers the Abrasion index by 2.7 points, and decreases the return fines by 4.4%. Moreover, the Reduction degradation index (RDI) was also improved by 7.9 points.

KEYWORDS:

• Iron ore sintering
• high alumina iron ore
• novel flux for sintering
• RDI
• abrasion index
• tumbler index
• return fines
• SFCA

Acknowledgements

The authors thank the management of Tata Steel, especially Mr Vinay V Mahashabde (Chief R&D and Product Technology) and Mr Surajit Sinha (Chief of Agglomerate), for the permission to use the necessary data in this publication. Thanks are also due to Mr Sajid Ansari, Mr Irfan Ansari, and Mr Anand Kumar Jha for experimental support. The authors also thank Dr Debashish Bhattacharjee (Vice President – Technology and New Material Business) for their support of this project.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was conducted internally by Tata Steel Ltd, India. No external agency was involved and no external funding was obtained to carry out this work.