Surface chemical studies on pyrite in the presence of polysaccharide-basedflotation depressants

The interaction of dextrin and guar gum with pyrite has been investigated t hrough adsorption, flotation, and electrokinetic measurements. The adsorpti on densities of the polysaccharides onto pyrite reveal a region of higher a dsorption density in the pH range 7.5-11, with a maximum around pH 10 for b oth polymers. The isotherms exhibit Langmuirian behavior. The adsorption de nsity of guar gum onto pyrite is higher than that of dextrin. Electrokineti c measurements indicate a decrease in the electrophoretic mobility values i n proportion to the concentration of the polymer added. Co-precipitation te sts confirm polymer-ferric species interaction in the bulk solution, especi ally in the pH range 5.5-8.5. The pH range for higher adsorption, significa nt co-precipitation, and appreciable depression of pyrite encompass each ot her. XPS and FTIR spectroscopic studies provide evidence in support of chem ical interaction between hydroxylated pyrite and the hydroxyl groups of the polymeric depressants. (C) 2000 Academic Press.