Utilization and Mechanisms of Tannic Acid as a Depressant for Chalcopyrite and Pyrite Separation

Abstract

Current flotation practices using lime or cyanide as depressants in chalcopyrite and pyrite separation have significant disadvantages, such as substantial reagent consumption, high slurry pH, and environmental hazards. This work aimed to explore the utilization and mechanisms of tannic acid (TA) as an eco-friendly alternative to lime or cyanide in chalcopyrite–pyrite separation. Flotation results showed that TA selectively depressed pyrite yet allowed chalcopyrite to float at neutral or alkaline pH. Adsorption density and zeta potential results indicated that TA adsorbed intensely on pyrite but minorly on chalcopyrite. Besides, potassium ethyl xanthate was still largely adsorbed on chalcopyrite but not on pyrite after TA adsorption. Surface analysis by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy further showed that the oxidation species of FeOOH and Fe2 (SO4)3, particularly FeOOH were the main active sites for TA chemical adsorption. Owing to the greater and faster oxidation of pyrite, more FeOOH and Fe2 (SO4)3 were generated on the pyrite surface, and the chemical adsorption of TA was more pronounced on the pyrite surface than on the chalcopyrite surface.

Synthesis of S-Allyl-O, O′-Dibutyl Phosphorodithioate and Its Adsorption Mechanism on Chalcopyrite Surface

“…Among them, copper metal is a very important basic material and strategic resource, which has been widely used in such important fields as electric power, electronics, machinery manufacturing, and national defense engineering, with large consumption [1][2][3][4][5]. Chalcopyrite (CuFeS 2 ) is the main source mineral of copper metal, but chalcopyrite often coexists with other sulfide ores, for example, pyrite [6][7][8]. Traditionally, chalcopyrite/pyrite separation is achieved under high alkalinity conditions by using inexpensive lime to depress pyrite flotation.…”