Abstract

Water recirculation in the mineral processing industry is a widely used alternative to address water scarcity. However, the quality of the recirculated process water is affected by the presence of undesirable species, such as residual flocculants, which can affect upstream processes such as flotation. In this work, the impact of an anionic polyacrylamide (PAM) on the flotation of chalcopyrite using potassium amyl xanthate (PAX) as a collector was investigated, considering different pH conditions, residual concentrations, and mechanical degradation of PAM molecules. The experimental methodology included microflotation tests, induction time measurements, reagents adsorption isotherms, and cyclic voltammetry. The results indicate that the presence of PAM in chalcopyrite flotation has a negative impact on its recovery across all evaluated levels of flocculant degradation and pH. This effect is mainly due to the adsorption of PAM molecules onto chalcopyrite particles, forming a hydrophilic surface coating which acts as a steric barrier that inhibits electrochemical reactions between PAX and chalcopyrite, affecting collector adsorption. Additionally, the increase in hydroxylated sites on the chalcopyrite surface with increasing pH, and polymer fragmentation due to mechanical degradation are key factors influencing this interaction mechanism. This background could be very useful for the proper management of recirculated process water and the optimization of the flotation process, contributing to improving the efficiency of copper production in the mineral processing industry. © 2025 Elsevier Ltd