Abstract: In order to reduce the wet tailings and alleviate the pressure of tailings storage，Meishan Mining has carried out the process optimization research on the 0.5~0 mm fine-grained pre-concentration system of gravity separation in mineral processing，aiming at the problem that the geological grade of raw ore has decreased year by year and the mud content of raw ore has gradually increased in recent years. The research focuses on the detailed sampling，investigation and research of each section of the whole gravity separation 0.5~ 0 mm system，and analyzes the influence of the decrease of geological grade and the change of raw ore properties on the system. The data analysis results show that the iron concentrate with iron grade of about 50% can be separated from the slime of the raw ore by the gravity separation 0.5~0 mm system，which has a great effect on reducing the wet tailings of beneficiation. However，the current concen⁃ tration capacity has reached a bottleneck and needs further optimization.

Key words: fine, quality index, concentration