Abstract: The TFe grade of iron ore produced from Jingtieshan V ore body of Jiusteel is about 23%.Due to the restriction of the technical level and economic conditions of mineral processing for many years,it has not been rationally utilized.The TFe grade of the selected ore is significantly improved by the single high intensity magnetic pre-selection process,but the TFe grade of the tailings is high and the iron loss is large.In order to further improve the effect of pre-selection,the combined discarding test of intelligent pre-selection and high intensity magnetic pre-selection was carried out.The results showed that:① For the samples with TFe grade of 23.92% and particle size of 15~45 mm,the optimal discarding rate was 16.31% with TFe grade of 26.53% and recovery rate of 92.83%.The stability test results of discarding rate of 13.20% and 20.39% are basically consistent with the conditional test results,indicating the reliability of intelligent pre-selection test data.② The suitable linear velocity of barrel surface in roughing for A1 sample (30~45 mm) was 0.70 m/s with TFe grade of 29.03% and recovery rate of 70.91% in concentrate.The suitable linear velocity on the surface of barrel in roughing for A2 sample (15~30 mm) was 0.85 m/s with TFe grade of 30.03% and recovery rate of 78.09% in concentrate.③ The intelligent pre-selection concentrate with particle size of 30~45 mm could remove tailings with yield of 15.04% and recovery rate of 8.29% by high intensity dry pre-selection,and TFe grade of concentrate increases by 2.04 percentage points.The intelligent pre-selection concentrate with particle size of 15~30 mm could remove tailings with yield of 10.97% and recovery rate of 5.79% by high intensity dry pre-selection,and TFe grade of concentrate increases by 1.54 percentage points.The intelligent pre-selection concentrate with particle size of 30~45 mm has better effect in high intensity dry pre-selection.④ The process of intelligent pre-selection and high intensity dry pre-selection (one roughing and one scavenging) was used to treat tailings with the particle size of 15~45 mm,and the tailings with the total yield of 24.12% and TFe recovery rate of 11.95% could be discarded.The TFe grade of concentrate was improved by 3.85 percentage points,indicating the better pre-selection effect.

Key words: V orebody in Jingtieshan, low grade, intelligent pre-selection, high magnetic dry pre-selection, particle size