A new surfactant dihexyl (2-amino-2-(hydroxyimino)ethyl) phosphonate as a collector to flotation separation of wolframite against quartz

Herein, a novel surfactant dihexyl (2-amino-2-(hydroxyimino)ethyl) phosphonate (DHAHEP) was synthesized by combining phosphonate and amidoxime groups in the same molecule, and used as a flotation collector for quartz vein-type wolframite. The Micro-flotation results showed that DHAHEP has excellent collection performance for wolframite, at pH 2 ∼ 4.5, the flotation recovery of DHAHEP for wolframite was over 90 %, while that for quartz was less than 60 %. The wolframite-quartz artificial mixed ores experiments demonstrated that at pH ∼ 4 and DHAHEP concentration of 8 × 10^-5 mol·L^-1, the flotation recovery of wolframite was 64.5 % and the grade was 48.9 %. Zeta potential and contact angle experiments elucidated that DHAHEP anchored on the wolframite surface mainly in the form of cations, increasing the hydrophobicity of the surface and thus separating the wolframite from quartz by flotation. FTIR, XPS, and DFT calculation further revealed that DHAHEP had an obvious flotation separation effect on quartz vein-type wolframite, it was mainly electrostatically adsorbed on the WO₄^2- sites on the wolframite surface in the form of cations, and also captured wolframite by forming chemical bonds with the Fe active sites through the phosphoryl and amidoxime groups in its molecular structure.