Abstract: Problems of weak treatment capacity of reverse flotation system of high intensity magnetic mineral of Sijiaying iron ore concentration plant are analyzed briefly, combined with treatment capacity of field devices, resonable reagent system test with pulp density around 50% was made in laboratory, phosphorus concentrate with iron grade above 67.50% were obtained at production field based on the best reagent system, grade of reverse flotation tailings was only 16%.

Key words: Oxide ore, High concentration, Flotation