Exploration of disodium methylenebis naphthalene sulfonatea as a novel depressant for the flotation separation of apatite from dolomite

To address the flotation separation problem between apatite and dolomite, DMNS (disodium methylenebis naphthalene sulfonate) was selected as a depressant in this research. Micro-flotation results showed NaOl exhibited good floatability for dolomite and apatite, with no significant difference in the floatability between these two minerals. The addition of DMNS completely depressed the floatability of dolomite but slightly affected the floatability of apatite. The artificial minerals mixture flotation ensured that DMNS achieved the separation between apatite and dolomite when the NaOl was used. The adsorption measurement illustrated adsorption amount of DMNS on dolomite surface was more than that of it on apatite surface, the Zeta potential results illustrated NaOl still adsorbed on the apatite surface but did not adsorbed on the dolomite surface after conditioning with DMNS. XPS analysis verified that no effective interaction occurred between DMNS and apatite surface, and DMNS chemically adsorbed on the dolomite surface by the interaction between -SO3H groups of DMNS and Ca2+/Mg2+ of the dolomite surface. First-principles calculations further ensured the higher adsorption energy of DMNS on the dolomite surface. The computational calculation also revealed that the interaction of DMNS with the dolomite surface was much stronger than that with the apatite surface.