A fundamental study of chalcopyrite flotation in sea water using sodium silicate

Abstract

Due to the shortage of fresh water, sea water has been considered as a promising alternative for mineral flotation. Sodium silicate (SS) was used to eliminate the negative influence due to the application of sea water for chalcopyrite flotation and the related mechanisms were studied. Flotation results showed that the most detrimental compound in sea water was the divalent ion of Mg2+. Contact angle measurements suggested that SS increased chalcopyrite hydrophobicity in sea water and MgCl2 solution. The zeta potential of chalcopyrite became more negative while that of Mg(OH)2 was reversed from positive to negative upon the addition of SS, preventing the adsorption of hydrophilic Mg(OH)2 precipitates on chalcopyrite surface. FTIR and XPS analyses further confirmed that the presence of SS in sea water reduced the adsorption of Mg(OH)2 on chalcopyrite surface. In addition, Derjguin-Landau-Verwey-Overbeek (DLVO) calculation indicated that SS can prevent the adsorption of Mg(OH)2 on chalcopyrite surface, thereby increasing chalcopyrite recovery. Therefore, this study presents an effective method to improve chalcopyrite flotation recovery in sea water.