关键词: 铁矿石, 预选, 阶段磨矿阶段弱磁选, 浮选

Abstract: An iron ore in Australian has a TFe grade of 36.36%，with magnetite as the main iron mineral，mFe distribution rate of 78.69%. The main gangue minerals are quartz，amphibole and mica， with SiO₂ content as high as 41.64%，while harmful impurities P and S are low. The ore is classified as acidic primary magnetite，with magnetite disseminated in a uniform medium-to-fine grain size，requiring fine grinding for satisfactory liberation. A beneficiation process comprising coarse wet pre-concentration， stage grinding and stage low intensity magnetic separation，reverse flotation and scavenging magnetic sepa⁃ ration was tested on this ore. The results show that the -4 mm HPGR product，after coarse wet pre-concen⁃ tration，can discard tailings with a yield of 20.16% and an mFe grade of only 0.21%，with an mFe loss rate as low as 0.14%，achieving effective early tailings rejection. The pre-concentrate，after first stage grinding to 87.70% passing 0.075 mm，yields a rougher concentrate of 56.66% TFe by low intensity magnetic sepa⁃ ration. After second stage grinding to 86.55% passing 0.038 mm，the second stage magnetic concentrate is further upgraded by cationic reverse flotation，and the flotation tailings are treated by scavenging magnetic separation followed by regrinding and reconcentration. The full scale locked cycle test finally produces an iron concentrate with a TFe grade of 67.15%，TFe recovery of 75.55%，and mFe recovery of 98.53%. This process effectively mitigates the adverse effects of increasing ore hardness and property fluctuations，signif⁃ icantly improves concentrate quality and recovery，and provides a technical reference for the efficient de⁃ velopment and utilization of similar magnetite resources.

Key words: iron ore, pre-concentration, stage grinding and stage low intensity magnetic separation, flo? tation