Insights into the synergistic adsorption mechanism of mixed SDS/DDA collectors on biotite using quartz crystal microbalance with dissipation

Abstract

Biotite is critical in numerous fields. The conventional magnetic separation method has many disadvantages. Herein, the flotation behaviors and mechanisms of sodium dodecylsulfonate (SDS)/dodecylamine (DDA) collectors on the biotite surface were investigated systematically by various characterizations, including surface tension measurement, fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) analyses, and quartz crystal microbalance with dissipation (QCM-D). Micro-flotation experiments showed that the recovery of biotite increased to above 90 % upon adding mixed SDS/DDA collectors under the concentration of 5 × 10−4 mol/L with a molar ratio of 5:1 at alkaline pH (10–11), while that of quartz was below 10 %. The surface tension tests showed that the mixed collectors were easier to absorb on interface due to a strong synergistic effect. The FTIR and XPS measurements indicated that DDA was absorbed on biotite through electrostatic attraction and hydrogen bonds, and SDS could be co-adsorbed by the interaction with DDA and the electrostatic attraction with metal ions of the biotite. The QCM-D data revealed that a rigid and thin adsorption film formed when DDA reacted with the biotite surface. After continuing to inject SDS, a rigid and compact multilayer was generated.