Abstract: To address the challenge in the flotation separation of molybdenite and talc due to their similar surface properties,
a reverse flotation system using xanthan gum (XG) as a depressant and dodecylamine (DDA) as a collector was developed
to achieve selective separation. The separation efficiency was evaluated through flotation tests on single minerals and artificially
mixed ores. The depression mechanism of XG on molybdenite and talc was systematically investigated using Zeta potential
measurements,contact angle tests,Fourier transform infrared spectroscopy (FTIR),SEM-EDS,and X-ray photoelectron
spectroscopy (XPS). Single-mineral flotation results showed that without DDA,XG significantly depressed both molybdenite
and talc. However,after the addition of DDA,the floatability of talc was restored,while molybdenite remained depressed. The
artificially mixed ore flotation results further confirmed that the combined action of XG and DDA enables effective separation of
molybdenite from talc. Mechanism studies revealed that in the system with XG alone,XG covered the surfaces of both minerals
through physical adsorption. In the XG+DDA system,XG formed a dense hydrophilic barrier on the molybdenite surface,blocking
the electrostatic adsorption of DDA and maintaining molybdenite in a hydrophilic,depressed state. In contrast,on the talc
surface,the pre-adsorption of XG did not hinder the further electrostatic adsorption of DDA,thereby restoring the hydrophobic
floatability of talc. The reverse flotation system composed of XG and DDA achieves efficient separation of molybdenite from talc
through a selective adsorption mechanism,providing a feasible approach for the flotation separation of talc-bearing molybdenum
ores.