Selective flotation separation of chalcopyrite and sphalerite by thermal pretreatment under air atmosphere

Thermal pretreatment was performed to enhance the flotation separation of chalcopyrite and sphalerite under the air atmosphere for the first time. Microflotation experiment showed that the floatability of chalcopyrite vanished after thermal pretreatment at above 170 degrees C. By contrast, the floatability of sphalerite was well maintained with a flotation recovery of 90%. In artificial mixed mineral flotation experiments, the separation of sphalerite and chalcopyrite was successfully realized by thermal pretreatment. Results of Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses indicated that the chalcopyrite surface was oxidized dramatically at 170 degrees C, and hydrophilic species such as sulfate (SO42-), oxides (CuO and Fe2O3), and hydroxyl species (Fe(OH)(3)) were formed on the surface. Hence, the adsorption of potassium butyl xanthate on chalcopyrite decreased significantly after thermal pretreatment. The reason for the higher oxidation speed of chalcopyrite than that of sphalerite was also analyzed.

Automated summary

Thermal pretreatment was used to enhance the flotation separation of chalcopyrite and sphalerite for the first time in this study. The results showed that thermal pretreatment at above 170 degrees C caused the floatability of chalcopyrite to vanish, while maintaining the floatability of sphalerite. Successful separation of the two minerals was achieved through thermal pretreatment, with the surface oxidation of chalcopyrite being a key factor.