Abstract: A low-grade scheelite（WO₃ content of 0.062%）beneficiation plant in He'nan uses Y1 as an inhibitor，but the quality improvement effect is not satisfactory.In order to improve the situation，a large number of inhibitor optimization experiments have been carried out. The results showed that the SH series inhibitors have poor applicability to the scheelite，and the effect of improving the rough concentrate grade is not obvious.The WT series inhibitors have strong applicability and can effectively improve the grade of scheelite rough concentrate. Compared with the single inhibitor，the combined use of WT series inhibitors has a more obvious effect on improving the grade of scheelite rough concentrate. Compared with the on-site inhibitor Y1，the combined inhibitor SG-1 has a lower dosage of 120 g/t.The WO₃ grade of the rough con⁃ centrate was increased from 0.805% to 1.257%，and the recovery rate only decreased by 0.46 percentage points. SG-1 has an excellent effect on enhancing the grade of low-grade scheelite rough concentrate.

Key words: scheelite, flotation, single inhibitor, combined inhibitor