Investigation of the interfacial adsorption mechanisms of 2-hydroxyethyl dibutyldithiocarbamate surfactant on galena and sphalerite

To enhance the selective separation of galena and sphalerite from their mixture minerals, 2-hydroxyethyl dibutyldithiocarbamate (HEBTC) surfactant was synthesized and its first applications on the flotation of galena and sphalerite were studied. The interfacial adsorption mechanisms of HEBTC on galena and sphalerite surfaces were also investigated by wettability measurements, FTIR measurements, XPS analyses and adsorption experiments. Compared with the two common collectors, sodium isobutyl xanthate (SIBX) and O-isopropyl-N-ethyl thionocarbamate (IPETC), HEBTC exhibited better selectivity for galena against sphalerite. The separation of galena from sphalerite can be achieved by using 4 × 10−4 mol·L−1 HEBTC as flotation collector. The results of the adsorption mechanisms demonstrated that HEBTC could improve the hydrophobicity of galena surface by chemisorption, but had weak effect on the hydrophobicity of sphalerite with no obvious chemical reaction. Adsorption kinetics and adsorption isotherm experiments revealed that the adsorption of HEBTC on galena surface could be well described by the Pseudo-second-order model and Langmuir model, respectively. The adsorption of HEBTC on galena surface was an endothermic and spontaneous process.