Abstract: This paper optimized the synthesis conditions such as molar ratio, temperature and time by examining quartz recovery and the active content of quaternary ammonium. The reverse-flotation results using roast-magnetite separation of Jiugang iron show that a concentrate with a grade of 56.54% and a recovery rate of 77.33% are obtained using M-N as collector. At 5-30℃, the reverse flotation result is stable, as well as the low-temperature resistance is excellent. Selectivity of M-N is superior to the traditional collector dodecylamine and ether amines. The result of Zeta potential and infrared spectroscopy reveals that the successful separation effect of M-N is due to electrostatic adsorption and hydrogen bonding on quartz.