Selective depression by using environment-friendly depressant pectin in apatite and dolomite flotation system.

[Display omitted] • Pectin can achieve selectively separation between apatite and dolomite. • Quantum chemistry was used to predict the reactive site of the polymer depressant molecule. • FTIR spectrum and Raman spectrum were used to analysis the selectively mechanism of pectin. • Pectin adsorbed on the dolomite surface by chelating with calcium and magnesium ions due to COO. The difficulty of apatite and dolomite to be efficiently separated by froth flotation due to similar physical and chemical properties of both minerals in using fatty acid collectors without any depressants. In this study, pectin was explored as an efficient and environment-friendly depressant in flotation to separate apatite and dolomite. In the micro-flotation experiments, pectin displayed an intense depressing effect in dolomite flotation and slightly affected apatite flotation. Quantum chemical calculation was used to predicated the reactive site of pectin, the results demonstrated that oxygen atoms of COO , OH and C O C in pectin display the most negative regions. The Zeta potential results indicated pectin was adsorbed on the dolomite surface selectively and depressed the adsorption of sodium oleate on the dolomite surface due to electrostatic repulsion effect. The Fourier transform infrared (FTIR) spectrum measurements uncovered that the selective separation of pectin was due to OH of pectin molecules. The Raman spectrum demonstrated that weak adsorption of pectin on the apatite surface was due to C O of pectin molecule, while the strong adsorption is regard as COO and C O C of pectin for dolomite. XPS results indicated that COO of pectin can chelate with Ca2+ and Mg2+ of dolomite surface and depress dolomite flotation. Hence, pectin was be utilised as an eco-friendly and highly selective depressant. [ABSTRACT FROM AUTHOR]