Selective adsorption of a new depressant Na2ATP on dolomite: Implications for effective separation of magnesite from dolomite via froth flotation

Up to now, there is still a great challenge to efficiently separate magnesite from calcium-bearing carbonate minerals, especially dolomite, via froth flotation owing to their similar physicochemical properties. In this investigation, a novel depressant adenosine 5'-triphosphate disodium salt (Na(2)ATP) was introduced into the flotation process using the collector sodium oleate (NaOl), which was proved to be effective for the separation of dolomite and magnesite. The flotation results demonstrate that Na(2)ATP exhibits a more intense depression on the flotation of dolomite than that of magnesite and can separate effectively magnesite from dolomite, which depends on much less NaOl adsorption onto dolomite in the presence of Na(2)ATP. Zeta-potential detection and adsorption amount tests illustrate that the pre-addition of Na(2)ATP strongly interferes with the interaction between NaOl and dolomite so that a more significant reduction in adsorption of NaOl on the surface of dolomite in comparison with magnesite. Moreover, infrared spectral (IR) and X-ray photoelectron spectroscopy (XPS) measurements further confirm that the depressant Na(2)ATP is adsorbed more strongly onto dolomite than magnesite. And the selective adsorption of Na(2)ATP onto dolomite rather than magnesite was mainly due to the strong bonding of its phosphate groups and the calcium sites only exposed to the dolomite surface, resulting in selectively depressing the flotation of dolomite.