Amine collectors are also called cationic collectors because they can produce cations with hydrophobic hydrocarbon groups after dissociation. They are mainly used to collect quartz, silicates, aluminosilicates, non-ferrous metal oxides and potassium salts, and are also used for the reverse flotation of iron ore to remove quartz. In order to better exert their efficacy, the following points should be noted when using them: (1) Prepare an amine salt that is easily soluble in water before use. Amine is a pale yellow waxy paste that is insoluble in water. In order to improve its water solubility, before use, hydrochloric acid and amine can be mixed in a 1:1 ratio to prepare an amine salt, which is easily soluble in water. After dissolving in hot water, dilute it with water to a 0.1% to 1% aqueous solution for use. The reaction formula is as follows: RNH₂ + HCl — RNH₂·HCl (2) Control the pH value of the slurry. When the pH of the pulp is greater than 10.65, amines exist in the pulp in a molecular state (RNH₂); when the pH of the pulp is less than 10.65, they mainly exist in a cationic state (RNH+). Some minerals (such as smithsonite) mainly react with molecular amines, requiring a pulp pH of 11 for flotation; while other minerals mainly react with cationic amines (such as using amines to collect quartz in iron ore reverse flotation), requiring a pulp pH of 8-9. Therefore, when using amine collectors, different pH ranges must be determined for different minerals to achieve good collection results.

(3) Slime should be removed before flotation. If the flotation material contains slime, amines are preferentially adsorbed by the slime, reducing their selectivity. In addition, because amines also have foaming properties, they will form a large amount of viscous foam with slime, making the operation difficult to control and dewatering difficult. Therefore, slime should be removed before flotation. (4) Amine collectors should not be added simultaneously with anionic collectors. This is because the ions of these two types of agents will react with each other in solution, forming insoluble salts with higher relative molecular mass, thus reducing the collecting effect of the amine.

(5) Amines can be used with neutral oils (kerosene or diesel oil), which can improve the collecting effect and reduce the amount of amine used.