Abstract: Analyzed the size composition of tin product separated by centrifugal gravity separation from yunnan tin corporation a tailings pond, and the distribution characteristic, phase,liberation of tin mineral. carried out the reelection test to the sample.The results show that from the gravity separation product can get tin concentrate with 4.28% grade and 46.71% recovery, and ferromagnetic middlings product with 36.79% iron grad and 77.78% recovery through the closed circuit of high intensity magnetic separation removing iron, settlement desliming, twice roughings once cleaning once scanvenging positive flotation, once roughing once cleaning once scanvenging reverse flotation, middlings return in order.

Key words: Cassiterite, Degree of liberation, Positive flotation, Reverse flotation