Abstract: Based on the research of various distribution of flotation feeding size on the reverse flotation process and results, it is concluded that large quantity of middlings will produced, both the reverse flotation process and indicators are destabilize, when the content of poorly liberated inter-particles is high in the feed. In comparison, when the grain size distribution of feeding is uniform, iron ore is well liberated, few of middlings quantity from reverse flotation, stability and balance of the reverse flotation process will easily achieved.

Key words: Anionic reverse flotation, Distribution of particles sizes, Inter-particle grains, Middlings quantity