Abstract: There is 32.45% Fe in iron ore from Donganshan Sintering Plant.The ore has the characteristics of poor iron and high silicon，main iron ore is hematite，main gangue mineral is quartz，there is also contains a small amount of siderite and magnetite.The ore belongs to siderite-bearing hematite ore.Sieve analysis on ground products of 70% -0.074 mm results indicated that，with the increase of particle size，the grade of iron grade increases gradually，monomer dissociation degree decreases.Classification closed circuit flotation experiment under the condition of the grinding fineness was carried out，-0.074 mm fraction using citric acid as dispersing agent，CaO as activator，starch as inhibitor，KS-Ⅲ as collector，+0.074 mm fraction using starch as inhibitor，dodecylamine as the collector，iron concentrate with iron grade of 63.30% and recovery of 71.32% was obtained.Compared with full fraction flotation，classification flotation can decrease the microgranular mineral adhesion cover cap，improve the flotation index.

Key words: Hematite, Siderite, Classification flotation, Dispersion flotation