The adsorption of isopropyl xanthate ions, (CH3)(2)CH-OCS2-, onto arsenopyrite (FeAsS) was studied through electrokinetics, voltammetry and rest potential measurements at pH 6. The electrokinetic behavior of droplets of isopropyl dixanthogen, (CH3)(2)CH-OCS2-S2CO-CH(CH3)(2), in solutions of isopropyl xanthate ions was also determined at the same pH value. Adsorption occurred first as isopropyl dixanthogen through an anodic oxidation reaction of the xanthate ions on arsenopyrite, with no effect on the zeta potential of arsenopyrite. Then as isopropyl xanthate ions through hydrophobic bonding with the dixanthogen adsorbed at the arsenopyrite/aqueous solution interface, increasing negatively the zeta potential of arsenopyrite. The negative electric charge at the dixanthogen-arsenopyrite/aqueous solution interface limited the two adsorption steps. Microflotation studies showed that arsenopyrite floated highly owing to dixanthogen. This flotation was not affected by the polar group (OCS2-) of the isopropyl xanthate ions at the dixanthogen-arsenopyrite/aqueous solution interface. (C) 2003 Elsevier Science B.V All rights reserved.