Abstract: In order to realize the efficient utilization of a high-silicon low-grade fluorite ore re⁃ source，aiming at the problem of the quality deviation of the fluorite concentrate，the experimental re⁃ search on the optimization of the flotation reagent system，the regrinding of the coarse concentrate and the addition of acidified water glass are systematically carried out.The test results show that the grade of CaF2 in concentrate is increased to 95.30% after the optimization of flotation reagent system. The regrinding of rough concentrate is beneficial to the increase of CaF2 grade of concentrate，but the recovery rate of CaF2 of concentrate decreases obviously. When the rough concentrate is reground to -0.075 mm 97.23%，the CaF2 grade of concentrate reaches 98.46% and the recovery rate is 40.58%.Acidified water glass is used as the inhibitor. When the coarse concentrate is reground to -0.075 mm97.23%，the CaF2 grade of the concen⁃ trate is 98.66% and the recovery rate is 44.74%. However，the industrial applicability of acid water glass is poor.In the flotation verification test，one roughing-one scavenging-one cleaning process and six cleaning processes after regrinding of coarse concentrate are adopted. Under the conditions of one-stage grinding fineness of -0.075 mm 50%，roughing sodium carbonate dosage of 1 000 g/t，sodium silicate dosage of 200 g/t，oleic acid dosage of 200 g/t and roughing concentrate regrinding fineness of -0.075 mm 97.23%， the high-quality fluorite concentrate with CaF2 grade of 98.55%，recovery of 41.99% and SiO2 content of 1.11% is obtained.It meets the requirements of fluorite concentrate quality standard（YB/T 5217—2019） FC-97.5C，and has remarkable economic benefits. It can provide technical support and theoretical basis for the efficient development and utilization of similar high-silicon low-grade fluorite ore.

Key words: fluorite ore, high silicon, flotation, quality improvement, regrinding, flotation reagent