Flotation separation scheelite from calcite by using a novel depressant of Poly(sodium 4-styrenesulfonate)

Scheelite and calcite was firstly separated by new depressant Poly(sodium 4-styrenesulfonate) (PSS) with NaOL system. The recovery of scheelite was 87.18 % and the recovery of calcite was 5.57 % in single flotation experiments, the recovery and grade of WO₃ was 70.53 % and 61.08 % respectively in artificial mixed ore flotation under the optimal conditions of 10 mg/L NaOL, 10 mg/L PSS and pH of 8. Contact angle measurements, atomic force microscope (AFM) analysis, zeta potential analysis, fourier transforming infrared spectra (FT-IR) analysis and X-ray photoelectron spectroscopy (XPS) analysis were performed to uncover the reaction mechanism. The results showed that PSS could not adsorbed on scheelite by chemical reaction, and PSS had no impact on the further adsorption of NaOL onto the scheelite surface. Therefore, scheelite could still keep a high recovery with PSS. However, PSS could be strongly adsorbed on calcite by chemisorption between the Ca site of calcite and O site of PSS, which increased the hydrophilia of calcite and imped the further adsorption of NaOL. Therefore, it could selectively depress the flotation of calcite.