DIELECTRIC STUDY OF SODIUM DODECYL-SULFATE (SDS) ADSORPTION ONTO GALENA - COMPARISON WITH SODIUM AMYL XANTHATE AND DODECYL AMMONIUM

The strong decrease of the permittivity of powdered galena with the ad dition of sodium dodecyl sulphate (SDS) can be linked, as in the case of sodium amyl xanthate, to the chemical nature of its bond with the g alena surface: physical adsorption of dodecyl ammonium chloride has no dielectric effect in the range 0.4-100 MHz. Voltammetry and electroki netic measurements show that the adsorption is independent of potentia l, contrary to the case of xanthate, and results from an exchange betw een SDS and anionic species onto the surface, X-ray photoelectron (XPS ) and diffuse reflectance by infrared Fourier transform (DRIFT) spectr oscopies have been investigated to identify the species responsible fo r the collection mechanism. (C) 1997 Elsevier Science B.V.