Interactions between Sulfide Minerals and Alkylxanthate Ions .2. A Vibration Spectroscopic and Atomic-Absorption Spectrophotometric Study of the Interactions between Sphalerite and Copper-Activated Sphalerite, and Ethyl-Decylxanthate and N-Decylxanthate Ions in Aqueous and Acetone Solutions
The reactions between three sphalerite samples and ethyl- and n-decylxanthate ions have been studied in aqueous and acetone solutions. Qualitative analysis of the species present on the sphalerite surfaces before and after treatment with these ions have been performed by means of diffuse reflectance infrared Fourier transform spectroscopy. Atomic absorption spectrophotometry has been used to determine the total zinc, iron and lead concentrations in the aqueous phase of sphalerite slurries before and after treatment with alkylxanthate ions. Sphalerite surfaces are hardly oxidized in air, and only small amounts of zinc are dissolved. No iron is dissolved from sphalerite with a low iron content, 0.5-1.0%, while both iron and lead are dissolved from a sphalerite sample containing 7% iron and 1% lead during the preparation of aqueous sphalerite slurries. Alkylxanthate ions are coordinated to sphalerite as surface complexes where the xanthate group is coordinated to the zinc sites in covalent interactions if no solid ethylxanthate species is formed on the surface. Lead-containing sphalerite acts like galena, and lead (II) alkylaxanthate precipitates on the surface. Zinc (II) ions in the sphalerite surface are exchanged for copper(II) ions during activation of sphalerite with copper(II) ions. In the reaction between copper(II)-activated sphalerite and alkylxanthate ions, copper(I) alkylxanthate and dialkyl dixanthogen are formed on the sphalerite surface.