Abstract: Aiming at the problems of low efficiency and high energy consumption in the conventional crushing and grinding process of low-grade，difficult-to-grind and difficult-to-separate iron ore，a high�efficiency and energy-saving crushing and grinding process with high pressure roller grinding as the core was developed by taking several concentrators of Masteel Mining as the research objects. A new crushing and grinding process of crushing-high pressure roller grinding-ball mill was formed by using high pres⁃ sure roller grinding as ultra-fine crushing equipment and combining dry and wet pre-selection tail discard⁃ ing technology，and two-stage series high pressure roller grinding and tower mill process tests were fur⁃ ther carried out. The results show that the high pressure roller grinding-preconcentration process can re⁃ duce the particle size from 18~0 mm to 3~0 mm，and the series roller mill test can reduce the particle size to -0.5 mm，and the content of -0.074 mm is more than 41%. The tower grinding process can reduce the power consumption by 35%，the ball consumption by 40%，and the concentrate grade by more than 65%. This process has achieved the goal of more crushing and less grinding，early throwing，significantly reduced the production cost of crushing and grinding，and improved the development ability of low-grade magnetite. The high pressure roller grinding series and tower mill process is an important development di⁃ rection to further save energy and reduce consumption and simplify the process. It has typical demonstra⁃ tion and promotion value in metallurgical mines.

Key words: high pressure roller grinding（HPRG）, prediscarding, tower mill, high efficiency and en? ergy saving, magnetite