Abstract: In order to study the effects of carboxymethyl amide inhibitors in hematite reverse flotation for silicate removal，using Polypropylene Carboxylic Acid(HPAM) and DWP-3 (compound of HPAM and small molecule anionic inhibitor DNL with mass ratio of 7∶3) as inhibitor，influence of the inhibitor on single mineral floatability of hematite and quartz were investigated.Single mineral flotation results indicated that，DWP-3 has poorer inhibitive ability than polypropylene carboxylic acid，but intense inhibitive ability on hematite.Zeta potential and infrared spectrum measurement results indicated that，as pH<2.95，there is electrostatic adsorption on quartz surface with HPAM and DWP-3，as pH>2.95，there is hydrogen-bonding adsorption on quartz surface with HPAM and DWP-3，as pH<3.53，there is electrostatic adsorption on hematite surface with HPAM and DWP-3，as pH>3.53，there is hydrogen-bonding adsorption and chemical adsorption on hematite surface with HPAM and DWP-3.

Key words: Carboxymethyl amide depressor, Hematite, Reverse flotation, Inhibition mechanism