Abstract: The flotation recovery rate of a refractory gold mine is only 80.95%，and the gold grade of tailings is as high as 1.0 g/t. In order to improve the flotation process index and strengthen the recovery of lost gold，the optimization test of flotation reagent system and the optimization test of middle ore regrinding process were carried out. The test results show that when the dosage of sodium carbonate，copper sulfate， butyl xanthate + ammonium dibutyl dithiophosphate and 2# oil is 5 000，500，470+250，100 g/t respective⁃ ly，the gold concentrate grade of 17.63 g/t，tailings gold grade of 0.74 g/t and gold recovery of 83.31% can be obtained by the combined middling regrinding process. After optimization，the flotation index of the pro⁃ cess is significantly improved，the gold concentrate grade is increased by 1.22 g/t，the gold grade of tail⁃ ings is reduced by 0.26 g/t，the gold recovery rate is increased by 2.36 percentage points，and the econom⁃ ic benefit is remarkable.

Key words: gold ore, flotation, pharmaceutical system, medium ore regrind, recovery rate, tailings grade