Adsorption mechanism of green efficient chelating poly-L-aspartic acid in flotation separation of brucite and dolomite

Abstract

Green and efficient reagents have gained considerable attention in flotation research, where poly-L-aspartic acid (PASP) is an effective reagent to realize the flotation separation of brucite and dolomite. The effect of PASP on the flotation of brucite and dolomite and its mechanism were studied using flotation tests and modern detection methods. Microflotation tests show that PASP can considerably reduce the flotation recovery of dolomite in the Sodium dodecyl sulfonate (‘SDS) system, whereas it only slightly affects the flotation recovery of brucite. Under ‘SDS, PASP can selectively reduce the contact angle of dolomite but only slightly affect that of brucite. Furthermore, atomic force microscopy detection and zeta potential tests demonstrate that PASP can strongly adsorb on the dolomite surface, considerably changing its roughness and potential value but slightly affecting brucite. The infrared spectrum analysis shows that PASP is selectively strongly adsorbed on dolomite, causing strong and weak ‘SDS adsorption on the surfaces of brucite and dolomite, respectively. Moreover, X-ray photoelectron spectroscopy demonstrates that PASP strongly impacts the Ca site of dolomite, and selective chelation of Ca is a key factor in inhibiting dolomite flotation.