Abstract: The specific rate of breakage(S_○1)and primary breakage distribution(B_i,j)of untreated and microwave-treated vanadium titano-magnetite(VTM) with different particle size were investigated using grinding kinetics， and the variations of surface topography and phase composition of ground products were analyzed. The results show that the breakages of both untreated and microwave-treated VTM obey the first-order grinding kinetics. The S_○1 of microwave-treated VTM is higher than that of untreated ore and the S₁ increment increases with increasing particle size. The primary breakage distribution parameters(γ) are dependent upon the feed particle size. The γ value of B_i,j of microwave-treated VTM is less than that of untreated ore. The SEM analysis shows that the ground products have smaller particle size and rougher surface after microwave treatment. The XRD analysis shows that microwave-treated VTM has stronger diffraction peaks and larger amounts of gangue phases after ball mill， compared to those of untreated ore， which indicates that the degree of dissociation of ore is improved.

Key words: microwave pretreatment, vanadium titano-magnetite, specific rate of breakage, primary breakage distribution function