Abstract: Fine grained iron concentrate in concentrated filter link has problems of slow sedimentation rate，large overflow suspended solid value，high concentrate filter cake moisture content and so on.By adding flocculants，the mineral grains floccules based on cohesion and bridging function，which promotes the sedimentation of fine ore grain.A hematite concentrate were as research object，the anionic，cationic，nonionic and amphoteric polyacrylamide as the flocculating agents，through the sedimentation test and Zeta potential measurement to examine the effects of polyacrylamide on flocculation and sedimentation behavior of fine-grained hematite.Test results show that,the interactions between ore grain and flocculation drug molecules include electrostatic force and hydrogen bond，Van Der Waals force，chemical adsorption，and Zeta potential plays a main role in this process or not and promotes or weakens this process which mainly depends on the type，the dosage of flocculants and pH value of the slurry.It provides theoretical basis and guidance for adding flocculants to select appropriate flocculant to promote the settlement of fine iron concentrate.

Key words: Fine-grained hematite concentrate, Flocculation, Sedimentation rate, Zeta potential