Abstract: Aiming at the problems of low tin grade, high content of fine slime and low recovery rate in the flotation process of fine tin ore in a tin oxide concentrator in Yunnan, a new reagent combination flota⁃ tion test was carried out with benzohydroxamic acid Bq collector as the core, foaming agent 2# oil and regula⁃ tor sodium carbonate. The closed-circuit test results show that the new reagent combination can obtain the index of tin concentrate grade of 5.89% and recovery rate of 80.90%, which is 3.83 percentage points higher than that of the original reagent. The industrial test further verified the applicability of the new reagent. Un⁃ der the condition of similar feed grade, the tin content of tailings decreased from 0.134% to 0.080%, the op⁃ eration recovery rate increased by 12.23 percentage points, and the concentrate grade of roughing 1 in⁃ creased from 0.770% to 10.37%, which could directly produce rich and medium ore and reduce the subse⁃ quent cleaning load. Although the new pharmaceutical system increased the cost by 9.54 RMB/t, the net in⁃ crease benefit was 72 RMB/t, and the annual economic benefit was about 8.63 million RMB. The research results provide a feasible technical route and practical basis for the efficient flotation of high mud and fine cassiterite.

Key words: tin ore flotation, Bq collector, fine-grained, industrial test