Abstract: An anion collector DZN-1 synthesized by Northeastern University was used to float the mixed magnetic concentrate of Qidashan dressing plant in Anshan Iron and Steel Company. The optimal rougher floatation condition is flotation temperature 25℃, pH of pulp 11.52, dosage of DZN-1 800 g/t, dosage of depressor CaCl₂ 200 g/t, and dosage of depressor carboxymethyl starch 600 g/t. At appropriate technical conditions, a closed circuit flotation flowsheet of single-stage roughing, single-stage scavenging, and middles returning was adopted to handle a mixed magnetic concentrate with Fe 46.02%. A concentrate of Fe concentrate grade 65.38% and recovery 89.56% was obtained. Test results showed that the characteristics of the anion collector DZN-1 are less activator dosage, lower flotation temperature, and better collecting ability.