It is proved that the process of cation reverse flotation is reliable to produce high purity iron concentrate with low silicon content.

Since 1978,Changsha Research Institute of Mining and Metallurgy had done various of deep and wide researches on this iron ore from laboratory tests to pilot tests,the pilot tests with the scale of dealing with 15 thousand tons of crude ore annually had been done by the flowsheet of magnetic roasting by rotary kiln-staged grinding-low intensity magnetic separation-cationic reverse flotation.

Based on the study of the properties of a micro-grained dissemination magnetite ore in Qinghai province and the analysis and comparison of experiments,the experimental research of the beneficiation flowsheet was made,namely the flowsheet consisting of staged grinding and low intensity magnetic separation and anionic reverse flotation,which obtained concentrates having 62.

78% iron was separated in the laboratory by using the craft flow of staged grinding and classification-gravity separation-magnetic separation-anionic reverse flotation.

The paper describes the characteristics of the technological of Nanfen red iron ore,beneficiation test research and the results of enlarged continuous test of the flowsheet consisting of the staged grinding,low intensity magnetic separation,high intensity magnetie separation,anionic reverse flotation.