Probing the improved collecting ability of dodecyl phosphate/poly-amine cation-anion association collector towards scheelite

Efficient flotation of scheelite is very important for the safety of tungsten resources. A brand new collector, i.e., cation–anion association, was designed by mixing potassium dodecyl phosphate (MAP-K) with amines including diethylenetriamine (DETA), triethylene tetramine (TETA) and tetraethylenepentamine (TEPA). The collecting performance of these cation–anion association collectors toward scheelite were systematically studied through micro-flotation, zeta potential, contact angle and adsorption capacity detection. The micro-flotation results implied that cation–anion association collector TTK (MAP-K and TETA at 2:1 M ratio) performed excellent collecting ability toward scheelite, and the recovery reached to 97.53% under concentration of 5.0×10⁻⁴ mol/L TTK, while that was only 70.37% with MAP-K. It was found that the zeta potential of TTK-treated scheelite was positive shifted, implying that the amino group was protonated in cation–anion association of TTK. The positively charged TTK may have an electrostatic attraction of scheelite, facilitating the adsorption of phosphate groups in TTK on scheelite surface. The adsorption energy of the TTK (−11.082 eV) was nearly the twice that of MAP⁻ (−5.072 eV). Therefore, DETA facilitated the adsorption of MAP-K on scheelite and strengthened the hydrophobicity of scheelite.