UTILIZATION OF FLUXED IRON ORE PELLETS IN BLAST FURNACE: A CRITICAL STUDY
Abstract - Iron ore pellets are major iron-bearing material for iron making units. Acid pellets are commonly used but they offer poor metallurgical properties like strength and poor high-temperature properties. So now a days more attention is towards developing fluxed pellets to improve the behavior and properties of iron ore pellets. Generally, pellets basicity varies from 0.3 to 0.5 in practical pellet plant. Flux addition not only improves physical and other metallurgical properties but also makes iron making process more economical by reducing the coke rate and improving the productivity of iron making units. Trials have been carried out to understand the effect of variation of basicity on different metallurgical properties of iron ore pellets by gradually increasing the basicity from 0.09 to 1.04 using bentonite as a binder. The second part of the study is consists of replacing bentonite by organic binder. Fluxed pellets with varying basicity from 0.16 to 1.16 are developed using lime as flux and organic binder. Lime is hardly used in iron ore pelletization because of its adverse effect on bentonite and it leads to crack formation in pellets. CaO affects the properties of bentonite at the beginning but at higher basicity, the CaO forms Ca(OH)2 which acts as a binding agent and improve green ball properties. Pellets of different basicity are tested for Green, Dry, and Fired pellet properties. Addition of lime results in improvements in the physical properties of pellets. Results suggest that organic binder pellets till
0.81 basicity satisfy all the requirement of green and fired pellet properties tested. In the case of bentonite pellets, CCS is low at low basicity while at higher basicity porosity is low hence pellets of basicity 0.27, 0.36. 0.48 have good properties.
Keywords - Fluxed Sintered; Basicity; Palletization; Organic Binders