Abstract:The gold grade in the desilting process of the second stage regrinding cyclone in the concentrator of Yinshan mine is 13.35 g/t, which is 1.35 times of the gold grade in the feed ore and 2.02 times of the gold grade in the overflow. By direct flotation of twostage regrinding cyclone, the copper concentrate grade is 27.55% , the copper recovery rate is 54.46% , the copper concentrate contains 366.31 g/t of gold and the recovery of gold in copper is 55.33% , the results show that there are some separated copper minerals and gold minerals in the sand-settling, and by pre-flotation, the fine minerals in the desilting can be reduced, and the re-grinding of the separated minerals in the vertical mill can be avoided, which leads to over-grinding, can achieve the goal of early harvest.