Abstract: The energy consumption of crushing and grinding accounts for a large proportion of the total energy consumption in the concentrator， but only 1% of the energy is used for the generation of new surfaces， resulting in a great waste of resources. As an effective pretreatment method， microwave irradiation can significantly improve the grinding effect of ore. In order to research the influence of microwave irradiation on the grinding effect of Anshan-type hematite ore， the conditions tests of microwave irradiation power， microwave irradiation time， ore block size and cooling method were carried out， and the grinding effect of Anshan-type magnetite ore was compared. The results showed that : ① Microwave irradiation can significantly improve the grinding effect of Anshan-type hematite， and the best microwave irradiation conditions are as follows: ore fragmentation from 20 to 25 mm， microwave irradiation power of 3 kW， irradiation time of 45 s， water quenching and cooling. Under these conditions， the contents of -0.074 mm particle size in the grinding products is 65.80%， which is 5.57 percentage points higher than that of the ore samples without microwave treatment. ② Under the same microwave irradiation conditions， the grinding effect of hematite is significantly better than that of magnetite. Microwave irradiation can significantly reduce the maximum compressive strength of Anshan hematite and magnetite， and the reduction of hematite is greater than that of magnetite. ③ The SEM microstructure analysis results show that obvious cracks appear between hematite and quartz after microwave irradiation， which is helpful to improve the selective grinding effect. The temperature rise curves of hematite and quartz showed that the temperature at the top of the center of hematite can reach more than 600 °C when the microwave irradiation power is 3 kW and the microwave irradiation time is 60 s， while the temperature of quartz almost does not change with the microwave heating time， which is helpful to realize the effective separation of useful ores and gangue minerals.

Key words: microwave irradiation, hematite ore, magnetite ore, grinding effect