Amyl xanthate uptake by natural and sulfide-treated cerussite and galena

The interaction of cerussite and galena with hydrosulfide and aqueous amyl xanthate at pH 9.5 has been investigated through zeta potential measurement s. Zeta potential results indicate that the hydrosulfide and xanthate anion s chemisorb or participate in surface reactions at both the cerussite and g alena/solution interfaces. Molecular lead xanthate appears to cover the sur face of amyl xanthate-treated cerussite whereas chemisorbed xanthate cowers the surface of galena under the same conditions. Sulfidization of the mine ral surface, which sets in only after sufficient sulfide is added to precip itate aqueous lead as lead sulfide, causes the zeta potential to drop sharp ly to highly negative values. The redox potential sensed by a Pt electrode remains almost constant at low reagent dosages, and becomes more negative o nce the hydrosulfide and amyl xanthate report to the solution. Excess sulfi de in solution, an indication of oversulfidized mineral surfaces, lowers th e redox potential and inhibits amyl xanthate adsorption. Redox potential me asurements may aid in achieving an efficient sulfidization of cerussite and oxidized galena for optimum xanthate adsorption and therefore flotation. ( C) 1998 Elsevier Science B.V. All rights reserved.