Abstract: In order to study the effect of molecular structure of dodecylamine， tetradecylamine， hexadecylamine and decyl ether amine on the flotation properties of foam， the bubble size in gas-liquid two phase system， and the foamability of the collectors， the amount of ore in unit volume of foam and recovery rate of foam water in gas-liquid-solid three phase system were studied with the aid of high-speed cameras and other testing equipment. The results indicated that: ① In the condition of the temperature of 15 ℃， pH value of 6.0 and the concentration below the critical coalescence concentration， the sauter diameter size of the bubble when the critical coalescence concentration was reached is in the following order: dodecylamine < decyl ether amine < tetradecylamine < hexadecylamine. ② With the increase of reagents dosage， the foam volume of dodecylamine， tetradecylamine and decyl ether amine after the action with quartz increased first and then decreased， while the foam volume of hexadecylamine decreased. ③ The amount of ore in unit volume of foam for dodecylamine almost does not change with the increase of the dosage of reagents. While the amount of ore in unit volume of foam for tetradecylamine， hexadecylamine and decyl ether amine increase first and then decrease， among which the change rate of hexadecylamine is the fastest， obviously higher than that of dodecylamine and tetradecylamine. ④ With the increase of the reagents dosage， recovery rate of foam water after the action with quartz of dodecylamine， tetradecylamine and hexadecylamine increased gradually， while the recovery rate of foam water of decyl ether amine decreased gradually. ⑤ The collision probability Pc increases with the decrease of the sauter diameter. Reducing the bubble diameter is an effective means to increase the flotation recovery rate， but the recovery of foam water increases， which made the gangue entrainment phenomenon serious.

Key words: Amine collectors, Bubble size, Foam properties, Mechanism