Abstract: The tin oxide ore from Yunnan with tin contents of 0.170% and iron contents of 4.66% is extremely sliming， which was considerated an iron-containing， low-grade， high slime and refractory tin ore. In order to develop appropriate dressing process and determine the optimal process conditions， the beneficiation process of the ore was studied based on study of properties of the ore. The results showed that: ① The ore contains 0.170% tin and the fine slime content of -0.019 mm is 12.74%. The main valuable mineral in the tin ore is cassiterite， followed by limonite， and the main gangue mineral is quartz. The tin mainly exists in the form of cassiterite and acid soluble tin， which is difficult to separate. ② Pre-discarding with spiral chute is a suitable pre-discarding method for the ore， and the optimal technological conditions are the +0.212 mm washing fraction ground to -0.074 mm occupying for 56.25%， the cut pocket width for concentrate end of spiral chute of 55 mm， the feeding pulp concentration of spiral chute of 30%， and the feeding pulp speed of spiral chute of 3.0 m3/h. The chute concentrate with yield of 32.65%， tin grade of 0.424% and tin recovery rate of 81.43% was obtained under those conditions. ③ Higher grade tin concentrate could be obtained after cleaning with shaking table， and high grade qualified tin concentrate could be obtained after deironing by high magnetic separation with tin shaking table concentrate. ④ After the combined process flowsheet of pre-discarding with spiral chute， cleaning with shaking table and iron removal by high intensity magnetic separation， the tin concentrate with yield of 0.22%， tin grade of 41.860%， tin recovery rate of 54.17% and tin rich middling with yield of 0.68%， tin grade of 4.950%， tin recovery rate of 19.80% were obtained. The cumulative recovery rate of tin concentrate and tin rich middling was 73.97% and impurity content of products did not exceed the standard， which realized separation of tin ore. Keywords Low-grade tin ore|High slime|Pre-discarding|Cleaning with shaking table|Iron removal by high intensity magnetic separation

Key words: Low-grade tin ore, High slime, Pre-discarding, Cleaning with shaking table, Iron removal by high intensity magnetic separation