Abstract: Flotation behavior of quartz， magnesite and dolomite in the presence of N，N-2 (3-chloride，2-hydroxypropyl)dodecylamine(NCDA) was investigated by flotation experiments. Properties and adsorption mechanism of NCDA were analyzed by zeta potential test， group electronegativity criteria and quantum chemistry calculation. Flotation results showed that， under the natural pH value of ore pulp， while the same dosages of collectors are added， NCDA has better ability to collect quartz than DDA， but the collecting ability of NCDA to magnesite and dolomite is obviously weaker than that of DDA. Results of zeta potential tests showed that NCDA adsorb on quartz surface by electrostatic adsorption and hydrogen-bond interaction. The calculation results of group electronegativity， hydrophile-lipophile balance and frontier molecular orbital energy indicated that NCDA has better collecting and foaming properties than DDA. Meanwhile， it is easier to interact with the quartz surface.

Key words: cationic collector, quartz, magnesite, dolomite, quantum chemistry, zeta potential