Adsorption

Engineering

Nanoparticle

Metallurgy

Materials science

Calcium

Mineralogy

Inorganic chemistry

Arsenopyrite

Chemical engineering

Nanotechnology

Organic chemistry

Chalcopyrite

X-ray photoelectron spectroscopy

Zeta potential

Chemistry

Alkalinity

Copper

Applied Surface Science

Herein, the effect of calcium ions on surface properties of chalcopyrite and arsenopyrite and its response to flotation separation under low-alkalinity conditions were investigated by flotation tests, zeta potential measurements, solution chemistry analysis, XPS tests, and DFT calculations. The flotation test results showed that calcium ions can selectively decrease the arsenopyrite floatability. The analysis results of zeta potential and solution chemistry showed that the positively charged Ca2+ and Ca(OH)+ were adsorbed on the chalcopyrite and arsenopyrite surfaces, and more adsorption of which on the arsenopyrite surface was found. Furthermore, the pre-adsorption of calcium ions greatly hindered the collector adsorption on the arsenopyrite surface while did not hinder that on the chalcopyrite surface. The XPS test results further demonstrated that CaOH+ was covered on the arsenopyrite surface via interaction with the Fe atom and S atom. Moreover, DFT calculation results revealed that the Ca-S bond can form on the chalcopyrite surface while the Fe-O bond cannot form. However, the Fe-O bond and Ca-S bond were both formed on the arsenopyrite surface, and the formed Ca-S bonds on the chalcopyrite surface were weaker than that on the arsenopyrite surface. Thus, a more hydrophilic surface of arsenopyrite was generated, which decreased its floatability.

Effect of calcium ions on surface properties of chalcopyrite and arsenopyrite and its response to flotation separation under low-alkalinity conditions