关键词: 含碳酸铁矿石, 弱磁选, 强磁选, 混磁精, 正浮选, 反浮选

Abstract: As mining depth increases in a domestic iron mine，the proportion of siderite-bearing iron ore rises.Due to its easy sliming characteristics，the traditional single reverse flotation process is un ⁃ able to produce qualified iron concentrate.To ensure stable operation of the processing plant and improve iron resource recovery，an optimization study on the beneficiation process of siderite-bearing iron ore was carried out based on process mineralogy analysis.The raw ore has an iron grade of 29.84%，with iron minerals mainly composed of hematite and limonite，accounting for a distribution rate of 54.26%.The sid⁃ erite content is 5.45%，with a distribution rate of 18.26%.The iron minerals are finely disseminated with a relatively narrow particle size distribution.A process of stage grinding—stage magnetic separation— stepwise flotation of mixed magnetic concentrate was adopted.Under the conditions of a grinding fineness of -74 μm accounting for 60%，a first-stage low-intensity magnetic separation field intensity of 135 mT， a high-intensity magnetic separation field intensity of 1.0 T，a tower mill grinding fineness of -45 μm ac⁃ counting for 90%，a second-stage low-intensity magnetic separation field intensity of 125 mT，and a high-intensity magnetic separation field intensity of 1.0 T，a mixed magnetic concentrate was obtained. Subsequently，through a process of direct flotation—reverse flotation of underflow—reverse flotation of froth，an iron concentrate with a yield of 26.62%，an iron grade of 65.36%，and a recovery rate of 58.31%was ultimately achieved，with an integrated tailings iron grade of 16.95%.The research results provide technical support for the efficient separation of siderite-bearing iron ore and have promising indus ⁃ trial application prospects.

Key words: carbonate-bearing iron ore, low-intensity magnetic separation, high-intensity magnetic separation, magnetic mixed concentrate, direct flotation, reverse flotation