Synthesis of a cationic organic silicone surfactant and its application in the flotation of smithsonite

•A new surfactant DTA was synthesized as collector for smithsonite flotation.•DTA displays superior flotation performances than conventional amine surfactants.•DTA exhibits superior selectivity for smithsonite against gangue minerals.

A cationic organic silicone surfactant (DTA) with specially designed functional groups was developed as a flotation collector for smithsonite. This surfactant was synthesized via the reaction between hexaethyldisiloxane and N-β-(aminoethyl)-γ-aminoisobutylmethyldimethoxy silane using tetramethylammonium hydroxide as a catalyst. Its flotation performance was validated by flotation tests using pure minerals. The results illustrated that DTA has strong collecting ability and better selectivity for smithsonite against quartz, calcite and dolomite compared to the traditional collectors such as octadecylamine, tetradecylamine and dodecylamine. Based on the analysis of FTIR spectra, zeta-potential measurements, X-ray photoelectron spectroscopy and density functional theory calculations, it can be concluded that the adsorption mechanism of DTA on the surface of smithsonite was mainly dominated by chemisorption and electrostatic adsorption. DTA's unique properties, which include two coordination sites (NH2 and NH), and the “parachute” shape structure of OSi(C2H5)3, resulted in superior collecting powers for smithsonite.