Combined inhibitory effect of calcium hypochlorite and dextrin on flotation behavior of pyrite and galena sulphides

Selective separation of pyrite from base minerals is very important and challenging. This research investigates the combined inhibitory effect of two novel reagents on flotation behaviors of pyrite and galena under the low alkaline conditions. The depression and adsorption mechanism of calcium hypochlorite [Ca(ClO)(2)] and dextrin (DX) on pyrite and galena were systematically studied via the microflotation experiments, reagent adsorption measurements and X-ray photoelectron spectroscopy. Flotation results showed that the combined effect of Ca (ClO)(2) and DX depressed the flotation of pyrite more strongly than that of their individual effect. An improved recovery difference of more than 60% between the galena and pyrite was achieved at pH 10 while using Ca (ClO)(2) and DX as depressant system and diethyldithiocarbamate (DDTC) as collector. Reagent adsorption measurements showed that the adsorption amount of DDTC onto pyrite surface was decreased significantly with the prior addition of Ca(ClO)(2) and DX. On the contrary, the surface of galena remained mildly inert in the presence of Ca(ClO)(2) and DX and thus adsorbed significantly more amount of DDTC. XPS analysis showed that, in the presence of Ca(ClO)(2), the surface of pyrite was severely oxidized to iron oxide/hydroxide species that promoted the adsorption of DX onto the pyrite surface. Based on the XPS analysis, an adsorption and depression mechanism of Ca(ClO)(2) and DX on pyrite and galena was also proposed.