Effect of Polymer–Surfactant Adsorption on the Hindered Settling of a Mineral Suspension

Competitive adsorption between anionic surfactant (SDS) and neutral poly(ethylene oxide) polymers (PEO) on carbonate mine tailings was investigated, with experiments being performed to check the order of reagent addition. The PEO adsorption plateaux were strongly affected by the presence of pre-adsorbed surfactant molecules, while surfactant adsorption increased in the presence of pre-adsorbed polymer. Polymer–surfactant interaction at the solid–liquid interface depended on the order of reagent addition which significantly affected the floc diameter. Increasing floc diameter was attributed to the formation of a polymer–surfactant complex on the solid surface.