Abstract: Changsha Non-ferrous Metallurgical Design and Research Institute Co.，Ltd.） Abstract The mineral composition of a tin polymetallic ore in Hunan Province is complex，among which the main valuable metallic minerals are cassiterite，galena，brittle antimonite，chalcopyrite and sphalerite，and the main gangue minerals are quartz，topaz，feldspar，mica and chlorite. The cassiterite in the ore is distributed unevenly and easy to be crushed in the grinding process. In order to improve the recovery effect of cassiterite，in the new system，the SnO₂ beneficiation process was optimized based on the test results and the original production process. High frequency fine screen was used as classification equipment to reduce the overcrushing of cassiterite. The classification-gravity separation technology was introduced to improve the separation of cassiterite by shaking. For the microfine cassiterite which was difficult to be recovered by gravity separation，the tin concentrate with Sn grade of 55% and recovery rate of 68.4% was obtained by flotation-centrifuge separator cleaning process after desliming. The production indexes and economic benefits by the new process are better than those by the original process.

Key words: tin polymetallic ore, screening, classification, gravity-flotation combination beneficiation