Abstract: In view of the problem that the flotation concentration increased from 32% to 38% ~ 42%，exceeding the design range of the original GF-40 flotation machine due to the increase of production and capacity expansion in a copper ore dressing plant，which leads to insufficient aeration of the equip⁃ ment，sink，efficiency decline and other problems，a systematic technical transformation was carried out. Based on the structural principle of XCF flotation machine，the optimization of core components such as spindle，impeller and stator and the construction of external aeration system were carried out for GF-40 flotation machine. After the transformation，the settling tank failure of the flotation machine was cured， and the operation stability was significantly improved. Under the premise of stable copper concentrate grade（>23%），the recovery rate increased slightly from 93.08% to 93.09%. The process transformation has also achieved the effect of reducing the cost of spare parts and reducing the labor intensity of workers， creating considerable economic benefits in the short term，and laying the equipment foundation for the sub⁃ sequent process optimization of the concentrator.

Key words: high-concentration flotation, air volume, flotation machine optimization, economic benefits