Experimental and molecular dynamics simulation study on DDA/DDTC mixed collector co-adsorption on sulfidized smithsonite surfaces

The significance of zinc oxide ore as an important supplementary source to meet the growing demand for zinc resources has been underscored. In this study, a combination of dodecylamine (DDA) and sodium diethyl dithiocarbamate (DDTC) was employed as a mixed collector system to enhance the flotation of smithsonite. The utilization of the DDA/DDTC mixed collector led to a remarkable flotation performance improvement of nearly 30% compared to using 2 x 10-4 M DDA alone. The evidence for the synergistic effect of DDA and DDTC was demonstrated through measurements of adsorption capacity and zeta potential. Moreover, solution surface tension measurements indicated that the mixed collector system contributed to a decrease in surface tension. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were employed to verify the simultaneous physisorption and chemisorption of DDA and DDTC on the sulfidized smithsonite surface. Additionally, the variation in contact angles demonstrated that the mixed collector effectively enhanced the hydrophobicity of smithsonite. Molecular dynamics (MD) simulations revealed that DDTC and DDA undergo multilayer adsorption on the smithsonite (101) surface, with DDTC promoting the adsorption of DDA.