Abstract: Research was done on grinding effect of 7 kinds of grinding aids to a magnetite in Hubei Province. The results indicated, under the condition of grinding concentration 70%,grinding time 2 min, proper grinding aids were all have remarkable grinding aid effect for grinding of magnetite. Lime, sodium hexametaphosphate, sodium tripolyphosphate, sodium pyrophosphate could increase the content of 0.075～0.045 mm size fraction in milling mineral discharging products greatly; sodium hydroxide, sodium silicate, sodium carbonate could increase the content of -0.045 mm size fraction in milling products greatly. Excess grinding aids not only have no grinding aid effect, instead it is against grinding.

Key words: Magnetite, Grinding aids, Particle size