Abstract: In order to improve the underflow yield of [?]660 mm hydrocyclone in Qidashan iron ore concentrator and increase the ore feed of subsequent gravity separation operation， the influence of hydrocyclone structure parameters on the separation performance of hydrocyclone was systematically investigated based on numerical simulation method. The results showed that the recovery of each particle size in the underflow can be increased by increasing the diameter of the spigot and the height of the column section， while increasing the diameter of the vortex finder and the cone angle presents the opposite trend. According to the results of numerical simulation， the industrial test of hydrocyclone used for coarse and fine classification was carried out. Compared with the original hydrocyclone， the underflow yield of the optimized hydrocyclone increased by 7.67 percentage， which can effectively increase the underflow yields under the premise of ensuring the separation efficiency. The ore feed of gravity separation operation can be increased by optimized hydrocyclone，which provides reference to the structural design of hydrocyclone in similar mines.

Key words: hydrocyclone, numerical simulation, separation performance, structure parameters