Polyethylene oxide assisted separation of molybdenite from quartz by flotation

Abstract

Low flotation efficiency has been suffered in beneficiation of low-grade molybdenum ores due to finer size liberation and crystal anisotropy. As reported, polyethylene oxide (PEO) was proved to improve flotation efficiency of micro-fine molybdenite particles visibly. In this study, PEO was employed to investigate the influence on flotation of micro-fine molybdenite particles from mixed ores and the underlying mechanisms were fully discussed by Atomic Force Microscopy (AFM), Focused Beam Reflectance Measurement (FBRM), Dynamic Light Scattering etc. The results showed that high consumption of kerosene could not achieve a desired recovery in flotation of micro-fine molybdenite from quartz. The introduction of PEO considerably increased flotation efficiency of molybdenite from quartz, and flotation selectivity was improved via pH and stirring speed adjustment. In the presence of PEO, pH affected flocculation capacity of molybdenite slightly while the flocculation capacity of quartz had a strong dependence on the pH. Adsorption amount and hydrodynamic radius of PEO molecules resulted in the phenomenon jointly. Stirring speed had a prominent effect on flocculation, de-flocculation and re-flocculation behaviors of molybdenite and quartz. Higher stirring speed scrubbed quartz from flocs due to weak attractive forces between molybdenite and quartz to reduce heterogeneous flocculation. Moreover, strong attractive forces drove molybdenite flocs reformation when suspensions were re-submitted to low stirring speed while quartz lost the flocculation ability. Hence, higher selectivity was achieved in the flotation of molybdenite from quartz with appropriate pH and stirring speed.