The production of calcium magnesium phosphate fertilizer by blast furnace method has certain requirements on the particle size of phosphate rock and flux entering the furnace. Screening off fine ore less than 10mm is one of the important prerequisites for smooth operation, high yield, stable yield and low consumption of blast furnace. However, at present, the content of fine ore in the raw phosphate ore is as high as 20-40%, so the treatment of fine ore has become an urgent problem to be solved in the current phosphate fertilizer plant.