Abstract: Sinosteel Maanshan Institute of Mining Research Co.,Ltd To the low grade iron ores from masteel nanshan mine area, taking completed Ultra-fine crushing circuit flow sheet with high pressure grinding roll, composed of high pressure grinding roll and wet-rough magnetic machine, can decrease the crushing size from -20 mm to -3 mm, realize the dressing idea of "more crushing and less grinding, energy-saving and cost-reducing". Ultra-fine with high pressure grinding roll, wet classification, pre-selecting rough particle size and discarding waste are important breakthrough to low grade iron ores. Pre-election of rough concentrate with staged grinding, using high efficient magnetic machines can get high grade iron concentrate even though the grade of feed ores are low.

Key words: Low grade iron ores, Ultra-fine, High pressure grinding roll, Wet classification, Pre-election of rough particle size