Abstract: BK414 was a new lepidolite flotation reagent developed by Beijing General Research Institute of Mining and Metallurgy. For the tantalum & niobium gravitation separation tailings with a Li₂O grade of 1.08% from Yichun tantalum & niobium ore, a concentrate of 3.79% Li₂O with a recovery of 63.09% could be obtained with BK414 as a collector through lepidolite flotation industrial test. Compared with cocoanut oil amine which had been used in Yichun tantalum & niobium ore, the lepidolite concentrate recovery could be improved by 8.07% with BK414 as a collector. BK414 has the advantages of good flotation index, low freezing point, little causticity and so on.