Three novel dithiocarbamate surfactants: Synthesis, DFT calculation and flotation mechanism to chalcopyrite

Three novel dithiocarbamate surfactants including 2-hydroxypropyl diethyldithiocarbamate (HPD-2), 3-hydroxypropyl diethyldithiocarbamate (HPD-3), and 2-(2-hydroxyethoxy)ethyl diethyldithiocarbamate (HED-2) were prepared and characterized by FTIR, 1 H/ 13 C NMR and HRMS. They were first employed as collectors to float chalcopyrite. DFT calculations were performed to anticipate the structure–reactivity of the novel dithiocarbamates, revealing that the reaction sites were primarily distributed in C S and OH groups. Compared with HPD-2 and HPD-3, HED-2 possessed a higher chemical reactivity owing to the C-O-C group. Microflotation results indicated that the collecting ability of the three dithiocarbamate collectors towards chalcopyrite followed as HPD-3 > HED-2 > HPD-2. FTIR and XPS demonstrated that HED-2 chemisorbed onto the surface of chalcopyrite through newly generated Cu S and Cu O bonds.