Flotation separation of magnesite and dolomite regulated by synergistic effect of acid etching and inhibitors

Abstract

ABSTRACT In this work, the synergistic effect of hydrochloric-acid etching and inhibitors on the flotation separation of magnesite and dolomite in the sodium oleate (NaOL) system was studied. Flotation tests revealed that the synergistic effect of acid etching and sodium hexametaphosphate, sodium alginate, and sodium lignosulfonate on the separation of magnesite and dolomite was poor. Meanwhile, the synergistic effect of acid etching with sodium carboxymethyl cellulose (CMC) could regulate the flotation separation of magnesite and dolomite over a wide pH range. Moreover, the synergistic effect of acid etching and CMC increased the flotation difference between magnesite and dolomite from 15.73% to 67.17%, and the selective separation index increased from 1.38 to 2.89. Characterization by atomic force microscopy revealed that acid etching altered the surface morphology of magnesite and dolomite, roughening their surfaces. Contact angle measurements, Fourier transform infrared spectroscopy analysis, and zeta potential measurements indicated that the synergistic effect of acid etching and CMC changed the wettability, charge, and adsorption performance of dolomite, selectively inhibiting the adsorption of NaOL onto the surface of dolomite, thereby inhibiting dolomite flotation. However, it has minimal effect on the floatability of magnesite.