Abstract: This is an article in the field of mining engineering. Ca²⁺ and Mg²⁺ are easily dissolved from fluorapatite and dolomite in the acid medium of reverse flotation, and there is a "cumulative effect" in the process of backwater circulation, which has an adverse effect on the flotation indexes. Taking fluorapatite, dolomite and quartz as the research objects, the effect of different recycle times of backwater on the flotation recovery of three single minerals was studied. The results showed that when pH value was 5, the recovery difference between dolomite and fluorapatite decreased from 72.21% to 64.19%, and the recovery of quartz maintained at about 10%; When the number of cycles reached 5, the recovery difference between dolomite and fluorapatite slightly increased to 69.74%, and the recovery of quartz slightly decreased to 11.22%. In this study, the mechanism of dissolved ions in backwater for three kinds of single minerals was revealed by measuring the number of dissolved ions, zeta potential of mineral surface and ions adsorption capacity of mineral surface under backwater circulation system.