Flotation of Molybdenite in the Presence of Sheared Polyacrylamide Flocculants

Flocculants type polyacrylamide (PAM) plays an important role in mineral processing circuits. It is common practice to reuse water from the thickening stages to other unit operations such as grinding and flotation. In the case of molybdenite flotation, an important depressing effect on mineral particles has been demonstrated by the residual flocculant dissolved in the recycled water. The aim of this work was to evaluate the effect of the degradation of a PAM type of flocculant on the flotation recovery of molybdenite. The study considered experiments of microflotation, adsorption isotherms, electrophoretic mobility, and intrinsic viscosity measurements. Molecular dynamic simulations were used to look for mechanisms of interactions between PAM and molybdenite. The results showed that molybdenite recovery was less affected by the flocculant when PAM molecules were subjected to more intense conditions of mechanical shearing. This behavior is related to the adsorption of flocculant on the mineral and the disposition and shape anisotropy of the flocculant chains.