LAUSR

Abstract The dissolved components of calcium-bearing gangue minerals that are adsorbed on the surface of magnesite can make it difficult to effectively separate magnesite from dolomite. In this study, ethylene glycol–bis(β–aminoethyl ether)–N,N,N′,N′–tetraacetic acid (EGTA) is used to enhance the effect of sodium hexametaphosphate (SHMP) and improve the separation of magnesite and dolomite using sodium oleate (NaOL) as a collector. A micro-flotation experiment demonstrates that a combination of EGTA and SHMP is more selective than SHMP alone. Inductively coupled plasma emission spectrometry and zeta potential measurements reveal that EGTA can strongly inhibit the dissolution of calcium ions on the dolomite surface and also decrease the effect of dissolved calcium ions on magnesite flotation. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy further suggest that EGTA, which is a Ca-selective chelator, could initially be adsorbed on the Ca adsorption sites of dolomite and act synergistically with SHMP to enhance the depression of dolomite.