Abstract: A low−temperature reverse flotation experimental study was carried out on the mixed magnetic concentrate from a processing factory in Anshan using a new fatty acid−based low−temperature resistant collector KDB−3. The results showed that the reverse flotation process of "one stage rougher flotation, one stage cleaning and three stage scavenging" was adopted for the mixed magnetic concentrate with 50.10% iron grade. When the roughing slurry temperature was 10 ~ 15 ℃, the dosage of inhibitor caustic starch was 650 g/t, the dosage of activator calcium oxide was 900 g/t, the dosage of collector was 1 150 g/t, and the dosage of adjusting agent sodium hydroxide was 900 g/t, and the dosage of sodium hydroxide was 900 g/t (pH=11.5), an iron ore concentrate with iron grade of 67.80% and recovery of 87.46% was obtained using KDB−3, while only an iron ore concentrate with iron grade of 66.57 % and recovery of 67.16% was obtained using sodium oleate as collector under the same experimental conditions, showing the remarkable effect of the novel collector. When the novel collector KDB−3 was used, an iron ore concentrates with an iron grade of 67.90% was obtained at room temperature (25 ℃), with a recovery of 89.18%, which was similar to the indexes under low−temperature conditions, indicating the applicability of the novel fatty acid type collector KDB−3 under both low−temperature and room−temperature conditions. Effective low−temperature flotation of iron ore from a processing plant in Anshan city was achieved.