Recovering iron values from iron ore slimes using cationic and anionic collectors

Abstract

Indian iron ore industry is one of the world’s largest and growing at a rapid pace. Approximately 15% of the plant input is discarded as slime into slime ponds. Slime dams are now considered as threat, due to lack of high grade ores and acute shortage of land. More over this slime also poses threat to the environment. In addition to the economic benefit from the utilization of the waste as a resource; it also minimizes the land requirement, surface degradation, groundwater pollution, and destruction of forests. Iron ore beneficiation plants in India gives in three products, coarse ore lumps, which are directly charged to blast furnace, the classifier fines with or without beneficiation are fed to sinter plants and the slime which contain high alumina and low Fe currently discarded as waste. Slimes are to be further beneficiated to produce concentrates low in alumina and silica. These slime which after pelletization can be used as burden for the blast furnace. In order to utilize iron ore slime an efficient gangue removal flotation process is indispensable. This research work presents the flotation route for the removal of gangue in the slime to a level which is acceptable for the blast furnace route production of iron. Research has been carried out effectively and efficiently to utilize iron ore slime from the slime ponds of Joda and Noamundi region, India. This research work presents the results on the application of flotation to obtain the hematite and goethite concentrate with low gangue content from iron ore slimes. Fine particle size, complex mineralogy and presence of locked particles make it impossible for direct production of hematite concentrate by froth flotation unless mineral surface specific collectors are used. With flotation of silicates by using cationic collector and starch as a depressant for iron ore, starch adsorption occurred on quartz particles covered by iron oxides and on minerals which contain, Fe (II), Fe (III), and Al ions in their structure. An entire flotation of mineral complex is possible if the collectors used are mineral surface specific. Flotation performance was optimized by carrying out design of experiments.