Selective inhibition of sodium tripolyphosphate on calcite in the process of magnesite flotation

In the flotation of magnesite, it is not easy to separate magnesite from calcite. Under this study, Sodium tripolyphosphate (STSP) was considered to be an inhibitor for improving the flotation separation efficiency of magnesite from calcite. Through relevant analysis, such as potentiodynamic potential measurement, infrared spectrum analysis, XPS testing and Quantum chemistry calculation, the selective inhibition of STSP on calcite was proved. Flotation results of pure minerals showed that the floating rate of calcite declined quickly from 90% to 15% in the wake of raise of STSP dosage, but the flotation recovery of magnesite remains high (recovery 90%) at pH 10.0. Then it was proved that the flotation separation of magnesite and calcite could be realized effectively under the right dosage of the reagent through the experiment of artificial mixed ore. Potentiodynamic potential changes and infrared spectrum analysis showed that STSP is easier to react with calcite, which prevented from the adsorption of NaOl on the calcite surface further. XPS analysis and DFT calculation further showed that STSP was strongly bound to Ca sites on the surface of calcite, but weakly bound to Mg sites on the surface of magnesite. Therefore, STSP is an effective flotation inhibitor for magnesite and calcite. (C) 2021 Published by Elsevier B.V.

Automated summary

In this study, the inhibitory effect of STSP on the flotation separation efficiency of magnesite from calcite was investigated. It was demonstrated that STSP selectively inhibits calcite, leading to effective flotation separation of magnesite and calcite under the right dosage of the reagent. Experimental results and analysis further confirmed the mechanism of STSP in inhibiting calcite and enhancing the recovery of magnesite.