Evaluation of the Suitability of Alternative Binder to Replace OPC for Iron Ore Slime Briquetting

Abstract

Iron ore slime is a powdery material of very fine size (<50 µm) generated during washing of iron ores. Despite of high iron oxide content, it can’t be used in the iron making process because of its higher alumina and silica content. In recent times, we have developed the process of making briquettes from iron ore slime as a coolant to replace iron ore lump in basic oxygen furnaces (BOF). Slime is hydraulically compacted using 10 wt% ordinary Portland cement (OPC) for binding to briquette shape and around 8 wt% of total charging material is fed to the BOF along with hot metal. The main objective of the present work is to find out an environment friendly, economically viable alternative of OPC binder for briquetting. Binder selection is done in such way that the total cost of briquette does not to exceed a 10 wt% OPC based reference. A range of binders which includes organic, inorganic and combinations of both are tested. It is observed that OPC and lime combination produces comparable properties. The replacement of OPC by lime can reduce the total cost of the binder and can lower the consumption of energy, as OPC production is energy intensive. It has less environmental impact than OPC, because the total CO2 emission is reduced.