Using new flotation reagents to directly float niobium oxide and iron oxide

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Many of the iron ore mines, including ArcelorMittal Mines Canada (AMMC) and Cliffs Wabush Mines who support this proposal, use gravity separation and magnetic separation to upgrade the iron ores to smelter grades. However, these separation technologies are not effective in recovering fine iron oxide minerals, which are lost to the tailings. For instance, Cliffs Wabush loses 5.6% of total iron value to the hydrocyclone overflow. Even if half of this amount is recoverd, it would mean an additional revenue of $12 million. AMMC loses the majority of the -75 µm iron oxide value to the spiral tailings. Therefore, it is important that suitable froth flotation reagent schemes and processing technologies, such as proposed in this project, be developed to directly recover the fine iron oxide value from the tailings. The proposed project will also develop flotation depressants to upgrade a niobium oxide concentrate, produced from Niobec Mine by a new collector hydroxamic acid, to market grade. Niobec Mine has been using a cationic collector to recover the niobium value from its ores. However, the cationic collector is not selective to niobium oxide so that the waste rock minerals need to be removed prior to the niobium recovery, which not only leads to complicated processes but also heavy losses of the value. Niobec Mine currently can only recover about 59% of the niobium because of the use of the cationic collector. With the support of a previous NSERC CRD grant, we have identified an anionic hydroxamic acid collector which can directly float the niobium oxide from the Niobec Mill Feed (0.7% niobium oxide), at niobium recovery of over 95% at a rougher concentrate grade of 1.4% niobium oxide. The proposed work is a continuation of the project to increase the concentrate grade to market value (40% niobium oxide) while maintaining high niobium recovery.