The utilization of tamarind seed gum as a novel dolomite depressant in the selective flotation of apatite from dolomite

Abstract

In this study, the separation of apatite from dolomite was first investigated by using tamarind seed gum (TSG) to depress the flotation of dolomite in sodium oleate (NaOL) collector system. The effects of pH and flotation reagents concentration were studied, and the results indicated that TSG could strongly depress the dolomite floatability rather than apatite floatability. A satisfactory separation effect was realized when pH was 9.0, TSG dosage was 10 mg/L and NaOL dosage was 40 mg/L, at which the recovery of single apatite and dolomite was 80.28 % and 3.46 % respectively, and the grade of P2O5 and the recovery of P2O5 of the concentrate was 35.86 % and 76 % respectively in mixed ore flotation experiments. To reveal the adsorption mechanism, the flotation reagents adsorption morphology, adsorption type, and adsorption site were analyzed through AFM images, zeta potential measurements, FT-IR spectra, and XPS spectra, respectively. It was found that TSG was adsorbed on apatite by hydrogen bond while adsorbed on dolomite by chemical bond. Hydrogen bond was weaker than chemical bond, thus NaOL could still express the strong adsorption on apatite surface when TSG was used as depressant, while TSG could impede NaOL to be adsorbed on dolomite. Therefore, TSG selectively restrained the flotation of dolomite, achieving the separation. Furthermore, the XPS results uncovered that the Ca and Mg of dolomite were the main active sites that react with TSG.