Potassium ethyl xanthate

About: Potassium ethyl xanthate is a research topic. Over the lifetime, 191 publications have been published within this topic receiving 2790 citations.

The role of metal hydroxides at mineral surfaces in dextrin adsorption, II. Chalcopyrite-galena separations in the presence of dextrin

Abstract: The adsorption of dextrin on chalcopyrite and galena was studied with a concomitant examination of the flotation behaviour of these minerals in the presence of dextrin. It was found that dextrin adsorbs on the sulphide surfaces through interactions with the surface metal hydroxide species. Since lead hydroxide and copper hydroxide appear in different pH ranges, selection of proper pH values, in line with these findings, was shown to lead to the separation of the chalcopyrite/galena mixtures when potassium ethyl xanthate (KEX) and dextrin were used.

Oxidation-Reduction effects in the flotation of chalcocite and cuprite

Abstract: A laboratory study of the batch flotation of chalcocite from chalcocite-quartz mixtures and of cuprite from cuprite-quartz mixtures with potassium ethyl xanthate as collector has shown that the oxidation-reduction state of the flotation pulp can have a pronounced influence on mineral floatabilities. At pH 11 chalcocite floated over a relatively narrow Eh range of about 300 mV; pH had no influence on the potential of the lower flotation boundary in reducing conditions but had a significant effect on the potential of the upper boundary in oxidizing conditions. Below this upper limit, the floatability was reversible with respect to Eh. Provided the Eh was in correct region chalcocite could be floated in the absence of measurable concentrations of dissolved oxygen. Cuprite displayed a high level of floatability with ethyl xanthate for which, by contrast with chalcocite, no flotation limit in reducing conditions was found; over a small range of potentials close to zero, its behaviour was strongly pH dependent. An attempt to account for the floatabilities of chalcocite and cuprite in terms of the formation of cuprous ethyl xanthate on their surfaces did not lead to correlations with the observed behaviour in reducing conditions but provided a rough correlation with the upper flotation potential limit. It is believed that more detailed and properly controlled comparative flotation studies of the chalcocite-xanthate and cuprite-xanthate systems could help to resolve some of the uncertainties associated with the effects of Eh, pH and oxygen concentration in sulphide mineral flotation.

Integrated copper-containing wastewater treatment using xanthate process.

Abstract: Although, the xanthate process has been shown to be an effective method for heavy metal removal from contaminated water, a heavy metal contaminated residual sludge is produced by the treatment process and the metal-xanthate sludge must be handled in accordance with the Taiwan EPA’s waste disposal requirements. This work employed potassium ethyl xanthate (KEX) to remove copper ions from wastewater. The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) were used to determine the leaching potential and stability characteristics of the residual copper xanthate (Cu-EX) complexes. Results from metal removal experiments showed that KEX was suitable for the treatment of copper-containing wastewater over a wide copper concentration range (50, 100, 500, and 1000 mg/l) to the level that meets the Taiwan EPA’s effluent regulations (3 mg/l). The TCLP results of the residual Cu-EX complexes could meet the current regulations and thus the Cu-EX complexes could be treated as a non-hazardous material. Besides, the results of SDLT indicated that the complexes exhibited an excellent performance for stabilizing metals under acidic conditions, even slight chemical changes of the complexes occurred during extraction. The xanthate process, mixing KEX with copper-bearing solution to form Cu-EX precipitates, offered a comprehensive strategy for solving both copper-containing wastewater problems and subsequent sludge disposal requirements.

Floatability of chalcopyrite and molybdenite in the presence of lignosulfonates. Part I. Adsorption studies

Abstract: The adsorption of six lignosulfonates on molybdenite and chalcopyrite was studied through direct adsorption measurements and size exclusion chromatography at natural pH (5.0–5.5) and pH 11. The tests were carried out using different reagents for pH adjustments, i.e., potassium hydroxide (KOH), lime (CaO), and sodium carbonate (soda ash – Na 2 CO 3 ). In the case of chalcopyrite, all the tests were performed in the presence of potassium ethyl xanthate – a chalcopyrite collector – added ahead of lignosulfonates. Overall, lignosulfonates give higher adsorption densities on chalcopyrite than on molybdenite. The adsorption density on both minerals was a function of not only the pH but also of the type of pH modifier used. Additions of lime enhanced lignosulfonate adsorption at higher pH but the adsorption of lignosulfonates dramatically decreased when soda ash or KOH were used for pH control. For all the lignosulfonates tested, higher molecular weight fractions tended to preferentially adsorb over lower molecular weight components. The results also indicated that electrostatic forces and chemical interactions between the anionic polyelectrolytes and metal-hydroxy sites on the mineral surfaces largely controlled the adsorption process.