Flaxseed gum as new depressant in the separation of apatite and dolomite and its mechanism

Abstract

Apatite was firstly separated from dolomite by utilizing flaxseed gum as depressant and NaOL as collector. Single mineral and apatite-dolomite binary mixed ore flotation experiments were performed. The results revealed that under the conditions of pH 8, flaxseed gum 40 mg/L and NaOL 40 mg/L, single apatite and dolomite recovery was 78.47% and 1.98% respectively. For the apatite-dolomite binary mixed ore flotation experiments, the P2O5 recovery and P2O5 grade of the concentrate was 76.43% and 39.39% respectively. Flaxseed gum could selectively depress dolomite flotation and achieve the separation of apatite from dolomite. Atomic force microscope (AFM), zeta potential measurements, Fourier transformed infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) were carried out to reveal the mechanism. The results revealed that flaxseed gum could not be adsorbed on apatite at pH 8, while it was chemisorbed on dolomite by the sites of Ca and Mg. Therefore, the NaOL could still be adsorbed on apatite at pH 8 and flaxseed gum could not impede it, but the further adsorption of NaOL on dolomite was hindered by flaxseed gum. Thus, flaxseed gum selectively depressed the flotation of dolomite and realized the separation of apatite from dolomite.