Abstract: The magnetic iron concentrate (91.60% -0.074 mm) of an iron plant in eastern Hebei province is fine disseminated.Its degree of iron liberation reaches 94.4%，and is obviously enriched in fine fractions.In order to increase the iron grade of the concentrate，iron increase and silicon reduction experiments was carried out with on-site concentrate as the object，micro-bubble countercurrent contacting flotation column as equipment，and GE-609 as the cationic reverse flotation collector.The results showed that iron concentrate with iron grade of 68.12%，recovery of 98.88% were obtained with pulp density of 35%，feeding speed of 893 mL/min，GE-609 dosage of 60 g/t，inflating volume of 2.0 L/min，foam layer of 30 cm through process of one roughing，two scavenging，middles back to the flow-sheet in turn,and 9.92% iron in iron tailings.It indicates that it is rational to deal the ore with micro-bubble countercurrent contacting flotation column and cationic collector GE-609.

Key words: Flotation column, Cationic collector GE-609, Reverse flotation, Iron increase and silicon reduction