Selective flotation separation of scheelite from apatite by application of ATMP as an efficient depressant

Abstract

The efficient separation of scheelite from apatite is still a big challenge by using froth flotation because of their similar surface’s properties. In this study, the novel apatite depressant of nitrilotri(methylphosphonic acid) (ATMP) was first used to separate scheelite from apatite. The selective depression behavior and adsorption mechanism of ATMP on the two minerals were explored by a serie of experiments and surface analyses. The flotation experiments results showed that ATMP exhibited an intense inhibition effect on the flotation of apatite rather than scheelite. A satisfactory separation result with scheelite recovery of 85.22% and apatite recovery of 23.6% was achieved when ATMP was used as the depressant in the sodium oleate (NaOL) system. AFM detection and Zeta potential measurements indicated that ATMP could selectively adsorb onto apatite surface and intensively impede the further adsorption of NaOL, while the adsorption of NaOL onto scheelite surface was rarely affected by the pre-addition of ATMP. Moreover, FTIR and XPS analyses revealed that ATMP was chemisorbed onto apatite surface, and the interaction sites between ATMP and apatite were phosphate groups of ATMP and calcium species of apatite, respectively. Therefore, ATMP could be applied as a potential apatite depressant for effectively separating scheelite from apatite.