Study on the foam behavior of amine reagents adsorbed at gas-liquid and gas-liquid-solid interfaces

Alkyl amines are widely used as cationic collectors in flotation. In this work, the flotation foaming behaviors of alkyl amines, including dodecylamine (DDA), di-n-hexylamine (DHA), octadecylamine (ODA), oleylamine (OLA), in the presence or absence of quartz were investigated by a new approach, "foam analyzer". The effects of pH, reagent dosage, concentration of quartz powder, and particle size on foaming property and stability of bubble were explored, and the physical model of foam structure evolution was established. The adsorption mechanism of amines on quartz surface was studied from molecular structure, surface tension, zeta potential, charging mode, and adsorption form. The results show the foam stability of four amine collectors as follows: OLA > ODA > DHA > DDA. In the range of pH=6-10, the foam properties of the four amines are better. Under the same conditions, the longer carbon chain of aliphatic amine, the more unsaturated bonds, the fewer hydrogen atoms of the amine group, and the corresponding foam properties are better. When the concentration of quartz powder is 8-10%, the foaming and stability of the foam of four kinds amines are the best, The finer quartz powder particle size, the more stable the amine foam and the stronger the foamability.