Abstract: The iron grade of the extremely poor iron ore used in the test is 13.90%,the harmful element phosphorus content is 0.86%,and the magnetic iron accounts for 46.04% of the total iron,mainly in the form of maghemite and magnetite,maghemite and magnet.The ore is dominated by a semi-self-morphing crystal structure with an inlaid grain size of more than 75% greater than 0.1 mm,and about 5% of the maghemite has a size of less than 0.05 mm.In order to determine the development and utilization process of the ore,a mineral processing experiment was conducted.The results show that the ore is treated by three-stage grinding process: the first stage grinding fineness is -0.076 mm 38.5%,the magnetic field intensity of low intensity magnetic separation is 115 kA/m,the second stage grinding fineness is -0.076 mm 74%,the magnetic field intensity of low intensity magnetic separation is 115 kA/m,the third stage grinding fineness is -0.043 mm 92%,and the magnetic field intensity of low intensity magnetic separation is 115 kA/m.Iron concentrate with 60.12% iron grade and 40.22% iron recovery was obtained.The sulphur and phosphorus content of iron concentrate is low,which meets the requirements of product quality.

Key words: Low grade iron ore, Stage grinding, Low intensity magnetic separation