Smithsonite flotation using mixed anionic/cationic collector

Abstract

The surface interaction and adsorption of the components in a mixture of surfactants are of considerable interest for both practical and theoretical reasons. The flotation behaviour of smithsonite in the presence of sodium sulphide (Na₂S) and a mixture of potassium amyl xanthate (KAX) and dodecylamine (DDA) and its adsorption on smithsonite surface at various concentration ratios have been investigated using zeta potential, contact angle, microflotation and diffuse reflectance FTIR studies. The smithsonite mineral has weak response to flotation in the presence of KAX alone as a collector. The presence of KAX enhanced the amine flotation recovery in the presence of sodium sulphide. The flotation results using mixed collectors showed the maximum recovery and contact angle were 95·5% and 104° at pH 12 respectively. The FTIR spectra revealed the coadsorption as amine–xanthate complex when mixed collector is used. The presence of KAX increased the DDA adsorption due to decrease in the electrostatic head–head repulsion between the two adjacent surface ammonium head group cations because the anionic KAX sitting between these two cations screens the electrostatic repulsion and increased the lateral tail–tail hydrophobic bonds.