The modified fatty acid collector α-bromododecanoic acid (α-BDDA) had a significant effect on the separation of chlorite and kaolinite. In this paper, the flotation separation of the independent lithium bearing mineral chlorite (cookeite) from the main gangue mineral kaolinite in clay-type lithium ore was studied. The results showed that when pH was 9, the concentration of CaCl2 was 1.64×10−4 mol/L, and the concentration of α-BDDA was 5.82×10−4 mol/L, the flotation separation effect of chlorite and kaolinite was the best, and the floating difference between them was 91.12 %. The flotation results of artificially mixed ore also proved that α-BDDA could realize the separation of chlorite and kaolinite. Adsorption amount analysis revealed that α-BDDA could adsorb both on chlorite and kaolinite, however, the amount of α-BDDA adsorbed on chlorite was much higher than that on kaolinite. Zeta potential analysis, FT-IR spectra analysis, and XPS analysis confirmed that α-BDDA could produce chemisorption on the surface of chlorite activated by CaCl2. The Al, Mg, Fe and Ca sites on chlorite could reacted with α-BDDA to form new chemical bonds. However, α-BDDA was adsorbed on kaolinite by weak physical adsorption, which was easily de-adsorbed by strong agitating or water washing.